موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Determination of point and extended source parameters of 5 April 2017 Sefid-Sang earthquake (Ml 6.0) in time and frequency domains using KIWI toolsتعیین پارامترهای چشمه نقطهای و گسترده زمینلرزه 5 آوریل 2017 سفیدسنگ (0/6Ml ) در حوزه زمان و فرکانس با استفاده از مجموعهابزار KIWI1207472510.22059/jesphys.2020.279918.1007111FAعلیرضانیکسجلدانشآموخته کارشناسی ارشد، گروه زلزله شناسی، مؤسسه ژئوفیزیک، دانشگاه تهران، تهران، ایرانظاهر حسینشمالیدانشیار، گروه زلزله شناسی، مؤسسه ژئوفیزیک، دانشگاه تهران، تهران، ایران0000-0001-6254-7560Journal Article20190601KIWI (KInematic Waveform Inversion) is a recently developed multi-step inversion tools at the Institute of Geophysics of University of Hamburg. The main aim of developing this method is to perform moment tensor inversion retrieving the point and extended source parameters in regional distances. In KIWI tools, point and kinematic source parameters are retrieved in a sequential process in three inversion steps in time and frequency domains using different inversion methods, parts of waveforms and so on. After the point source inversion done, the method retrieves the radiation pattern, including fault plain parameters, Scalar moment and centroid depth. Also, for large enough earthquakes (Mw>5.5), extended source inversion retrieves finite source parameters such as rupture directivity, rupture area and velocity, rise and rupture time, average slip and nucleation point regarding to the point source centroid location. KIWI tools uses pre-calculated Greens functions, hence, the inversion process is quite fast. Due to the same reason, this method is rendered for automatic real-time retrieval of point and extended source parameters. In general, we can highlight the most important characteristics and applications of KIWI tools as follows: ability of easy implementation for real-time retrieval of source parameters, stability of inversion, rapid directivity detection, no requirements of aftershocks and foreshocks, no limitation in depth and magnitude and ability of retrieving reliable results even in absence of accurate velocity model used to build the Green’s functions and large stations azimuthal gap. In this research, we introduce the KIWI tools and use its applications to study of the April 5, 2017 (Ml 6.0) Sefidsang-Fariman earthquake. The data used in this research were recorded by permanent broadband stations of International Institute of Earthquake Engineering and Seismology (IIEES) and some global broadband stations from IRIS network at a minimum epicenteral distance of 200 kilometers. To have a better evaluation of KIWI tools functionality, we made inversion of source parameters using six different set of information (including IASP91 and IRSC velocity models and the mentioned set of data). Then, the information set including IRSC velocity model and all available data considered as the optimum one. Comparing the obtained results using the optimum set of information and the remaining sets, Maximum difference in centroid depth, Latitude and Longitude is 1.9 kilometer, 0.23 and 0.5 degree related to information sets including only IRIS network data, while there is a good consistency in retrieved focal mechanisms. After all, it is tried to run a sensitivity test using the optimum information set to have a better assessment on KIWI tools stability in source parameters analysis. Based on the achieved results, the erroneous input parameters (e.g. Latitude, Longitude and Depth) had a low influence on our optimum results. The final results in this research represents the centroid of earthquake in a shallow depth (7.1 km) with a magnitude slightly larger than those published by other institutions like USGS (Mw 6.2). Retrieved focal mechanism shows mainly reverse faulting with small dextral strike-slip component dipping north-east which is in a good accordance with the Kashafrood fault characteristics as the closest active fault to the epicenter. Also, extended source inversion revealed mostly unilateral source directivity toward SE with a rupture area, rupture time and approximate average sleep of 300 km<sup>2</sup>, 9.3 seconds and 16 cm.مجموعه ابزار KIWI (KInematic Waveform Inversion)، یک روش جدید در تعیین سازوکار کانونی و پارامترهای چشمه زمینلرزههای ناحیهای است که در آن با انجام برگردان در دو حوزه زمان و فرکانس، پارامترهای چشمه نقطهای و گسترده تعریف شده در مدل چشمه اِیکونال (eikonal) طی فرآیندی مرحلهای تعیین میشود. هدف از این مطالعه، تعیین پارامترهای چشمه نقطهای و گسترده زمینلرزه 5 آوریل 2017 سفیدسنگ (0/6Ml ) ضمن تشریح مراحل برگردان در مجموعه ابزار KIWI است. شکل موجهای استفاده شده در این تحقیق برگرفته از ایستگاههای دائمی باندپهن پژوهشگاه بینالمللی زلزلهشناسی و مهندسی زلزله (IIEES) و شبکه جهانی IRIS است. بهمنظور ارزیابی عملکرد مجموعه ابزار KIWI، فرآیند برگردان با استفاده از شش زیرگروه اطلاعاتی مختلف (شامل مدل پوسته IASP91، مدل پوسته میانگین ایران (IRSC) و دادههای مذکور) انجام شده که در این بین مجموعه متشکل از مدل سرعتی IRSC و کل دادههای موجود بهعنوان مجموعه اطلاعاتی بهینه در نظر گرفته شده است. نتایج حاصل از برگردان با استفاده از مجموعه اطلاعاتی بهینه بیانگر جنبش عمدتاً معکوس با مؤلفه راستالغز راستگرد با شیب بهسمت شمالشرق است که با مشخصات گسل کشفرود همخوانی دارد. پارامترهای چشمه نقطهای نظیر عمق مرکزوار و بزرگای گشتاوری زمینلرزه بهترتیب 1/7 کیلومتر و 2/6 بهدست آمد. برگردان پارامترهای چشمه گسترده نیز نتایجی چون جهتیافتگی عمدتاً یک طرفه بهسمت جنوب شرق، مدتزمان شکست 3/9 ثانیه، مساحت شکست 300 کیلومتر مربع و نیز میانگین لغزش 16 سانتیمتر را بهدست داده است.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Curie point depth from spectral analysis of aeromagnetic data for reconnaissance exploration of geothermal potential; Case study: east of Kerman Provinceتخمین عمق کوری با استفاده از آنالیز طیفی دادههای مغناطیسی هوابرد جهت پتانسیلیابی منابع زمینگرمایی؛ مطالعه موردی: شرق استان کرمان21347473010.22059/jesphys.2020.284503.1007134FAمحمدفهیمآویشدانشجوی کارشناسی ارشد، گروه مهندسی معدن، دانشکده فنی و مهندسی، دانشگاه شهید باهنر کرمان، کرمان، ایرانحجتالهرنجبراستاد، گروه مهندسی معدن، دانشکده فنی و مهندسی، دانشگاه شهید باهنر کرمان، کرمان، ایرانآزادهحجتاستادیار، گروه مهندسی معدن، دانشکده فنی و مهندسی، دانشگاه شهید باهنر کرمان، کرمان، ایران0000-0002-1950-3607سعیدکریمینسبدانشیار، گروه مهندسی معدن، دانشکده فنی و مهندسی، دانشگاه شهید باهنر کرمان، کرمان، ایرانJournal Article20190720In the recent decade, there has been an increasing interest in developing various resources of renewable energy as an alternative to fossil fuels in Iran. Geothermal energy is one of the promising reservoirs and exploration of geothermal favorability has become one of the main research interests in most parts of the country. Some reconnaissance studies have shown that the Kerman Province can be one of the geothermal potential regions in Iran. Different studies are being performed to prepare the geothermal favorability map for Kerman Province. <br />The aim of this study is to estimate the Curie point depth (CPD), heat flow and geothermal gradient from spectral analysis of aeromagnetic data for reconnaissance exploration of geothermal resources in the east of Kerman Province, southeast of Iran. This area is selected because it is characterized by thermal manifestations such as several hot springs with temperatures between 20–73°C, faults, and igneous rocks in the southern and southwestern parts. <br />Aeromagnetic data were first processed for removing the geomagnetic main field (using the International Geomagnetic Reference Field (IGRF)), reduced to pole (RTP) and band-pass filter. Then, we used spectral analysis technique to estimate the top and bottom boundaries of the magnetized crust. Comparison of magnetic map with geologic map shows a good correlation between the exposed geological units and magnetic signatures. Strong variations in magnetic intensity suggest a variety of magnetic properties. Bandpass filtered data were produced from the RTP aeromagnetic anomalies to isolate near surface and undesired deep effects. Then, the map was divided into thirty blocks, each having 50% of overlap with the adjacent block. A first-order trend was removed from each block, and grids were expanded by 10% using the maximum entropy method to make the edges continuous. Then, each block was analyzed using the spectral centroid method to obtain the depths to the top, centroid and bottom of magnetic sources. First, we calculated the radially averaged log power spectrum of each block. To compute the spectrum of the data, the magnetic anomaly of the area was transformed by 2D Fourier to obtain the average Curie depth. From the slope of the very long wavelength part of the spectrum, the centroid depth (Z<sub>0</sub>) was estimated, while the average depth to the top (Z<sub>t</sub>) was estimated from the second longest wavelength part of the spectrum. Using the values obtained for Z<sub>0</sub> and Z<sub>t</sub>, the depth to the bottom (Z<sub>b</sub>) was calculated for each block using the equation Z<sub>b</sub>=2Z<sub>0</sub>−Z<sub>t</sub>. The depths obtained for the bottom of the magnetized crust are assumed to correspond to Curie point depths where the magnetization of the layer disappears. Variations of the Curie isotherm level can correlate to some indices of geothermal activity (e.g., geothermal gradient and near-surface heat flow) in the study area. <br />The results showed that Curie point depth in the study area varies from 8.5km to 18.2km, and accordingly, the geothermal gradient ranges between 31-67°C/km. The heat flow was estimated in the range 139-294mW/m<sup>2</sup> in the study area. The results showed the shallowest Curie depths occurring in the southern part of the area. This is the zone which mainly hosts volcanic rocks and hot springs.در این مطالعه از آنالیز طیفی دادههای مغناطیسی هوابرد در محدودهای در شرق استان کرمان جهت شناسایی مناطق دارای شار زمینگرمایی استفاده شد. ابتدا تصحیح مربوط به میدان مغناطیسی مرجع با مدل <em>IGRF</em> انجام و سپس فیلتر برگردان به قطب بر روی دادهها اعمال شد. سپس بهمنظور حذف اثرات ناشی از توپوگرافی، خصوصیات زمینشناسی و میدانهای مغناطیسی هسته، از فیلتر میانگذر استفاده شد. پس از بلوکبندی محدوده و انتقال دادهها به فاز فوریه، طیف توان هر بلوک محاسبه شد. عمق بالایی ( ) و عمق مرکزی ( ) هر بلوک از منحنیهای لگاریتمی طیف توان بهدست آمدند. عمق کف منابع مغناطیسی ( ) که بهعنوان عمق کوری در نظر گرفته میشود از رابطه محاسبه و برای تخمین گرادیان زمینگرمایی و شار زمینگرمایی منطقه استفاده شد. نتایج نشان داد کمترین عمق کوری (5/9-5/8 کیلومتر) با بیشترین گرادیان دما و شار زمینگرمایی در جنوب کویر لوت (جنوب شرق محدوده) و جنوب غرب گلباف در محدوده راین با واحدهای آذرین متنوع و بیشترین عمق کوری در کویر لوت و واحدهای رسوبی شمال منطقه قرار دارد.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Investigation of pre-seismic activity effect on recorded VLF signals in
Tehran receiverبررسی اثر فعالیتهای پیش لرزهای در سیگنالهای VLF ثبت شده در گیرنده تهران35497473110.22059/jesphys.2020.285776.1007139FAمعصومهالهی سرشتدانشآموخته کارشناسی ارشد، گروه زلزله شناسی، مؤسسه ژئوفیزیک، دانشگاه تهران، تهران، ایرانمهدیرضاپوراستاد، گروه زلزله شناسی، مؤسسه ژئوفیزیک، دانشگاه تهران، تهران، ایران0000-0002-8112-7083Journal Article20190803Electromagnetic phenomena such as disturbance of VLF (very low frequency) radio signals, have been used for prediction of short-term earthquakes in the world from some years ago. VLF signals are reflected from the lower bound of the ionosphere, so any change in the ionosphere D region leads to changes in the conditions of the VLF wave propagation. One of the factors that influences the various parameters of the ionosphere is the processes surrounding the earthquake center before it occurs. So far, several hypotheses have been proposed for the mechanism of energy penetration from the earthquake to the ionosphere in theory. One of the most appropriate hypotheses is the role of atmospheric gravitational waves in this regard. However, there are not many observational evidence. In this study, after a review of variations in VLF signals received at the receiver of Tehran University's Institute of Geophysics (TEH), significant disturbances were observed several days prior to the onset of the Mn 5.8 Sirch earthquake that occurred on 22 July, 2018, in Kerman province, southeastern Iran. These abnormalities appeared as decreasing in the night range and increasing in the amplitude of the day and were only in the VTX3-TEH pathway, so they did not have any relation to the disorder in the transmitter or receiver. The association of these abnormalities with the factors affecting the ionosphere, including Solar flares, Lightning, Meteorological and geomagnetic activities was also studied and risk associated with these factors were rejected. These abnormalities began about four days before the earthquake and continued until the day of the earthquake; therefore, they are probably related to the precursor effects of the Sirch Kerman earthquake. Spectral analysis of signals was also performed and a 20 minutes harmonic was found in the spectrum of days before the earthquake. This period is not observed in the quiet days. This result, in addition to denying the probability of a geomagnetic effect on the signal, shows the effect of atmospheric gravitational waves in the lithosphere-atmospheric-ionospheric coupling mechanism for this earthquake. Based on these observations, the radio anomaly under study can be considered as a precursor of the Sirch earthquake in Kerman. The 22 July 2018 Mn 5.8 Sirch earthquake disturbances in Kerman provide another evidence of radio frequency disturbances at the VLF frequency before the earthquake. However, for more accurate monitoring of these signals, regular monitoring of long-term data as well as the number of more receivers in the country is required. In this case three important features, an earthquake pre-indicator, the time, location and magnitude of the earthquake in VLF/LF anomalies, occur from about a week to a maximum of 10 days before the earthquakes (Biagi, 2009) and are suitable for short-term forecasting, but still the exact time of earthquake is not clear. The disturbances do not appear for earthquakes with magnitude less than 5.5 and for earthquakes between 5-6 disturbances are less severe than earthquakes larger than 6, so this method may estimate the magnitude of the earthquake. Also, using an appropriate network coverage of the VLF/LF receivers and the use of appropriate processing methods, it is possible to locate somewhat an earthquake. Finally, it can be said that this new field of science is considered as a promising candidate for short-term earthquake prediction to reduce earthquake damage in active area such as Iran.پدیدههای الکترومغناطیسی ازجمله اختلال در سیگنالهای رادیویی (VLF, Very Low Frequency) برای پیشبینی کوتاهمدت زمینلرزه از چند سال پیش در دنیا مورداستفاده قرارگرفتهاند. سیگنالهای VLF از مرز پایینی یونوسفر بازتاب مییابند بنابراین هر تغییری در منطقه D یونوسفر شرایط بازتاب امواج VLF را تغییر میدهد. احتمالاً یکی از عواملی که پارامترهای مختلف یونوسفر را تحتتأثیر قرار میدهد، فرآیندهای اطراف کانون زمینلرزه قبل از وقوع آن است. تاکنون چند فرضیه برای مکانیسم نفوذ انرژی از کانون زمینلرزههای با عمق کمتر از 40 کیلومتر به یونوسفر بهصورت تئوری پیشنهاد شده است. یکی از مناسبترین فرضیهها نقش امواج گرانشی جوی در این رابطه است با این حال مدارک مشاهدهای زیادی وجود ندارد. در این تحقیق تغییرات مشاهده شده در سیگنالهای VLF دریافت شده در گیرنده مؤسسه ژئوفیزیک دانشگاه تهران (TEH)، بهعنوان پیشنشانگر قبل از وقوع رخداد لرزهای مورد بررسی قرار گرفته است. در بازه زمانی و مسیرهای مورد مطالعه تنها زمینلرزه نسبتا بزرگ، زمینلرزه 5.8 Mn سیرچ کرمان در تاریخ 22/07/2018 میباشد. نتایج نشان میدهد که اختلالات واضحی چند روز قبل از وقوع زمینلرزه سیرچ کرمان مشاهده میشود که پس از بررسی عوامل مختلف مؤثر بر سیگنال میتوان آن را بهعنوان یک پیشنشانگر برای این زمینلرزه در نظر گرفت. همچنین تحلیل طیفی سیگنالهای VLF فرستنده VTX3 در جنوب هند که در گیرنده تهران دریافت شدهاند، بررسی شده است و نتایج آن نقش نوسانات گرانشی جوی را بهعنوان مکانیسم اتصال لیتوسفر- یونوسفر بهصورت مشاهدهای تأیید میکند.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Using fuzzy inference system to model the Earth’s displacement fieldاستفاده از سیستم استنتاج فازی (FIS) برای مدلسازی میدان جابهجایی پوسته زمین51667473210.22059/jesphys.2020.286298.1007141FAمیررضاغفاری رزیناستادیار، گروه مهندسی نقشهبرداری، دانشکده مهندسی علوم زمین، دانشگاه صنعتی اراک، اراک ایران0000-0002-5579-5889مهدیمحسنیدانشجوی کارشناسی ارشد، گروه مهندسی نقشهبرداری، دانشکده دانشکده فنی مهندسی، دانشگاه آزاد اسلامی واحد اهر، اهر، ایرانJournal Article20190805Today, by the expansion of geodetic networks and the creation of base points for geodetic applications, the study of the motion of the earth's crust and the study of the activity of faults are the most important tasks of geodesic. With the establishment of satellite positioning systems, the creation of base points in geodetic networks has been substantial. The basic point in creating base points is the estimation and obtaining the velocity field and the displacement of these points in a reference framework. Determining velocity field with the high precision and the displacement of the base points in geodetic networks is of great importance. With the availability of information on the velocity of GPS stations in a geodetic network, one can model the kinematics and dynamics of the earth's crust in that area. In this regard, extensive research on these problems has been conducted around the world. <br />The main objective of this paper is the use of Fuzzy Inference System (FIS) for modeling the surface displacement field in Iran. The concept and study of fuzzy logic began in 1920, but the fuzzy logic was first used by Lotfizadeh (1921-2017) in 1965 at Berkeley University. FIS can formulate the behavior of a phenomenon in terms of the use of descriptive and empirical rules without the need for an accurate analytical model. The fuzzy inference system is the tool for formulating a process with the help of rules as if-then. The set of these fuzzy rules is called the fuzzy rules base. Argumentation is done using a fuzzy inference system. The fuzzy inference system is generally made up of the following components: <br />1. Fuzzy, 2. Base rules, 3. Fuzzy Inference Engine, 4. Diffusion. <br />The process of converting explicit variables into linguistic variables is called fuziation. The inference engine evaluates and deduces the rules using inference algorithms, and after the rules are combined, the output is converted by the divisible unit into an explicit or numerical value. The most common type of fuzzy inference system is the Tacagi-Sugeno fuzzy system. <br />In this paper, the FIS is used to model the surface displacement field of the Earth's crust in Iran. A fuzzy inference system is a system that uses the rules of the if-then-fuzzy rules to recognize the properties of the phenomenon. Since this system is capable of modeling nonlinear phenomena, in this paper it is used to model the surface variations. For better and more accurate evaluation, the results of the fuzzy inference system were compared with the results of GPS velocity field observations as well as the results of the artificial neural network (ANNs). To do this, 5 test stations have been considered and observations of these 5 stations have not been used in fuzzy network and neural network training. Based on the analysis, the maximum relative error calculated at the 5 test stations for the fuzzy network and the neural network in the eastern component were calculated to be 20.02% and 29.74%, respectively. The results indicate that the fuzzy network has more accuracy than the artificial neural network in speed field modeling.در این مقاله از سیستم استنتاج فازی (FIS) جهت مدلسازی میدان جابهجایی سطحی پوسته زمین در منطقه ایران استفاده شده است. سیستم استنتاج فازی سیستمی است که از پایگاه قواعد اگر-آنگاه فازی برای شناخت ویژگیهای پدیده مورد نظر استفاده میکند. با توجه به اینکه این سیستم قابلیت مدلسازی پدیدههای غیرخطی را داراست، در نتیجه در این مقاله از این روش جهت مدلسازی تغییرات سطحی پوسته زمین در فلات ایران استفاده شده است. همچنین برای ارزیابی بهتر و دقیقتر، نتایج حاصل از سیستم استنتاج فازی با نتایج مشاهدات میدان سرعت حاصل از ایستگاههای GPS و همچنین نتایج حاصل از شبکه عصبی مصنوعی (ANNs) مورد مقایسه قرار گرفته است. برای انجام اینکار پنج ایستگاه آزمون درنظر گرفته شده و مشاهدات مربوط به این پنج ایستگاه در آموزشهای شبکه فازی و شبکه عصبی مورد استفاده قرار نگرفته است. براساس آنالیزهای انجام گرفته، بیشینه مقدار خطای نسبی محاسبه شده در پنج ایستگاه آزمون برای شبکه فازی و شبکه عصبی در مؤلفه شرقی (V<sub>e</sub>) بهترتیب برابر با 02/20 درصد و 74/29 درصد محاسبه شده است. همچنین برای مؤلفه شمالی (V<sub>n</sub>) میدان سرعت، بیشینه مقدار خطا برای هر دو روش بهترتیب برابر با 80/18 درصد و 05/27 درصد تعیین شده است. نتایج بیانگر این موضوع است که شبکه فازی از دقت و صحت بیشتری نسبت به شبکه عصبی مصنوعی در مدلسازی میدان سرعت برخوردار است.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Total electron content modeling in terms of spherical radial basis functions over Iranمدلسازی محتوای الکترونی کلی بر حسب توابع پایه شعاعی کروی در منطقه ایران67807473310.22059/jesphys.2020.286297.1007142FAشایانخوشگواریدانشجوی کارشناسی ارشد، گروه ژئودزی، دانشکده مهندسی نقشهبرداری، دانشگاه صنعتی خواجهنصیرالدینطوسی، تهران، ایرانیزدانعامریاناستادیار، گروه ژئودزی، دانشکده مهندسی نقشهبرداری، دانشگاه صنعتی خواجهنصیرالدینطوسی، تهران، ایران0000-0003-4854-3402هانیمحبوبیدانشجوی دکتری، گروه ژئودزی، دانشکده مهندسی نقشهبرداری، دانشگاه صنعتی خواجهنصیرالدینطوسی، تهران، ایرانJournal Article20190805Satellite positioning using single frequency receivers and space technologies such as radar and communication systems all demand a precise knowledge of the ionosphere. Ionosphere is the upper layer of atmosphere which is ionized and affects the transmission of electromagnetic waves depending on their frequencies. Parameters that characterize this layer of the atmosphere are the Ionospheric Electron Density (IED) and the Total Electron Content (TEC). Hence, modeling and understanding of TEC in a precise way is an undeniable necessity. International Reference Ionosphere (IRI) and Global Ionospheric Maps (GIMs) are the sources of information that provide TEC values globally for all users. It could be expected that the accuracy of such global models in some regions like Iran are not suitable since these models are obtained from the global data sources which they lack a good density in Iran plateau. Thus, regional TEC modeling over Iran needs more attention. In this study, the total electron content obtained from the permanent dual-frequency GPS receivers are utilized in regional TEC modeling. Estimation of TEC requires satellites and receivers Differential Code Biases (DCB) to be known. DCB values for satellites and the International GNSS Service (IGS) receivers can be observed from IGS analysis centers e.g. the Center for Orbit Determination in Europe (CODE). However, for local dual frequency receivers to be used for the purpose of TEC monitoring, their DCB should be estimated. In this research, the DCB value of each station is computed from observations which their corresponding elevation angles are more than 60 degrees. The DCB computation process consists of 3 steps. First, Vertical Total Electron Content (VTEC) is obtained from the spatial and temporal interpolation of (IGS-IONEX) files. Second, each interpolated VTEC is multiplied by a mapping function. After that, the difference of the observed pseudo-range of the two frequencies is denoised via a moving average filter. Eventually utilizing the interpolated VTEC and smoothed difference of the observed pseudo-ranges and the mapping function, DCB values of all stations are estimated. Thereafter, a parameterization of the estimated VTEC over the study area is implemented. For this purpose, the Spherical Radial Basis Function (SRBF) method is used. These functions are compact support and more practical for interpolation of observations on a regional scale. It is necessary to mention that the optimization of the depth of SRBFs plays an important role in increasing the accuracy of the regression. The coefficients of the expansion are computed by least squares estimation, and the Tikhonov regularization method is used in which the regularization parameter is obtained from L-curve. Some of the observations are excluded from the dataset as check points for evaluation of the constructed model. In this research, once the modeling process is conducted over Iran and also the north-western region of Iran which has a more proper distribution of data, is parameterized on the 124th day of 2016. The height of the ionosphere layer is assumed 450 km above the earth's surface. Then aregular grid of point-mass functions that has the simplest form of SRBFs is constructed. Then, by changing the depth of the grid, an optimal depth is estimated at which the best accuracy is obtained at the check points. The results reveal that the parameterization of TEC with a regular grid of SRBFs in which the number of grid points are approximately 10% of the number of data, leads to the construction of a model whose accuracy in the check points is significantly enhanced comparing to GIMs. In addition, the accuracy of the modeling is better in areas where data density and distribution are more appropriate. The results of this research show that the accuracy of VTEC modeling in the whole region of Iran in 0 to 1 Universal Time (UT) and 10 to 11 UT are 0.87 and 1.30 TECU respectively. According to the GIMs VTEC accuracy of 1.91 and 1.97 TECU in the same periods of time, it is concluded that the accuracy of VTEC modeling in this research is improved by 1.04 and 0.67 TECU with respect to GIM. In addition, with increasing the density of data distribution and limiting the study region to the north west of Iran, the accuracy of the proposed model is equal to 0.33 and 1.66 TECU. With respect to the GIMs accuracy this is equal to 1.87 and 1.92 TECU, the proposed method has an improvement of about 1.54 and 0.86 TECU comparing to the GIMs model.مدلسازی پارامترهای چگالی الکترونی یونسفر (IED) و محتوای الکترونی کلی (TEC) در تعیین موقعیت ماهوارهای با گیرندههای تک فرکانسه، مطالعات فیزیک فضا، عملکرد سیستمهای راداری و ارتباطات مخابراتی ضروری است. مدلهای مرجع بینالمللی یونسفر (IRI) و نقشههای جهانی یونسفر (GIMs) منابع اطلاعاتی هستند که TEC را در مقیاس جهانی در اختیار کاربران قرارمیدهند. این مدلها از منابع دادههای جهانی بهدست آمدهاند که در منطقه ایران دارای تراکم مناسبی نیستند، بنابراین دقت آنها در این ناحیه کم است. لذا مطالعه و مدلسازی محلی TEC در منطقه ایران دارای اهمیت است. در این مطالعه مدلسازی TEC برحسب توابع پایه شعاعی کروی (SRBF) و با استفاده از مشاهدات شبکه دائم GPS ایران انجام شده است. در این مطالعه مدلسازی TEC در روز 124ام سال 2016 در کل منطقه ایران که دادهها دارای تراکم یکنواخت نیستند و همچنین در محدوده شمال غرب ایران که دادهها دارای تراکم یکنواختتری هستند، صورت گرفته است. نتایج مدلسازی نشان میدهند که مدل ارائهشده از GIMs دقیقتر است و همچنین دقت مدلسازی در منطقه شمال غرب ایران که توزیع مشاهدات یکنواختتر است، بیشتر میباشد. در کل منطقه ایران دقت مدلسازی VTEC با روش مقاله برای بازه زمانی 0 تا 1 و 10 تا 11 ساعت جهانی بهمیزان 04/1 و 67/0 در مقیاس TECU نسبت به GIMs بهبود مییابد. همچنین محدود کردن ناحیه مدلسازی به شمال غرب ایران و افزایش تراکم توزیع دادهها، موجب بهبود دقت بهمیزان 54/1 و 86/0 TECU نسبت به GIMs میشود.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Introducing an integrated strategy in fault modelling with multi-attributes in 3D seismic data in a field from Persian Gulfارائه استراتژی ترکیبی مدلسازی گسلها بهروش چند نشانگری در دادههای لرزهای سهبعدی در یکی از میادین خلیج فارس81967473610.22059/jesphys.2020.286837.1007147FAایمانصمدیدانشآموخته کارشناسی ارشد، گروه مهندسی نفت و ژئوفیزیک، دانشکده مهندسی معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود، شاهرود، ایرانمعصومهکردیاستادیار، گروه مهندسی نفت و ژئوفیزیک، دانشکده مهندسی معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود، شاهرود، ایرانمهردادسلیمانی منفرددانشیار، گروه مهندسی نفت و ژئوفیزیک، دانشکده مهندسی معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود، شاهرود، ایرانامیراحمدیکارشناس ارشد، شرکت نفت فلات قاره ایران، تهران، ایرانJournal Article20190824Fault and fracture modelling is an important step in reservoir engineering which is required for any reservoir characterization and production management. There are various types of methods and strategies for building such models, however, each has its own advantages and drawbacks. The most important issue that should be considered is the ability to model both large- and small-scale faults, simultaneously. It is important, as large faults define geological frameworks of the reservoir, while small faults influence fluid movement in the reservoir. In this study, we introduce an integrated strategy for modelling small- and large-scale faults by seismic data, using multi-attributes. Large faults are defined by hand picking from seismic data using attributes, and small faults are modelled by an automatic ant tracking algorithm. Then, two separated models are integrated to build a unique, but multi-scale fault model. Result of each step of modelling is evaluated by well data. The methodology is applied on a hydrocarbon reservoir from the Persian Gulf. Results show that the multi scale fault model is accurate when evaluated by well data. <br />Integrated modelling of faults of fractures to obtain a unique multi-scale model is an interesting topic in reservoir engineering. Normally fractured reservoirs are divided into several production zones based on division made by large faults, while fluid movement in each zone is controlled by small fracturs and faults. Thus, obtaining a unique model which contain information of faults in several scale is under investigation. However, conventional methods use separate sources of information for modelling faults in various scales. Large scale faults are normally modelled by seismic data while well data are used for modelling small faults. Ozkaya (2019) stated that modelling of faults both with seismic and well data would reduce uncertainty in reservoir fracture modelling. Cao et al. (2019) introduced an integrated strategy for modeling faults with two scales in 2D seismic data, but using seismic and well data. Kurison et al. (2019) have modelled faults and fractures in reservoir with 3D seismic data and well data, but in separate manners. But their final interpretation has shown that using both types of model would result in better reservoir modelling. Xu et al. (2019) introduced an integrated strategy for modelling faults and fractures in two scales simultaneously using seismic and well data. In this study, we introduce an integrated strategy for multi-scale fault modelling using only seismic data, which could be used in reservoirs which lack of well data. <br />The proposed strategy introduced here, initiates with a geological model building. Subsequently, large faults can be defined on seismic data and related attributes. Simultaneously, small scale faults can be modelled by an ant tracking algorithm in an automatic manner, then it would be refined by interpreter to remove other lineaments than fault that was modelled by the algorithm. Each model then would be evaluated by well data and in case of any error in the model, they would be removed by more ant tracking parameter optimizations and also deeper investigation by the interpreter. In the final step, both fault model would be integrated to build a unique informative multi-scale fault model which contains information of all faults in various sizes. Other characteristics of faults in the integrated model would be investigated for further analysis. <br />Large scale fault model showed major faults with northwest-southeast trending acting in the center of the reservoir, which has a dome shaped structure, and some minor faults with various trending around the major one. Through this modeling curvature, chaos and variance attributes were used for better fault detection. Small faults obtained by ant tracking distributed around the center of the field. Ant tracking algorithm parameter were optimized through sensitivity analysis prior to application. Afterwards, fault model was refined to remove non-fault lineament. Both models were evaluated by a fullbore formation microimager (FMI) log which proved fractures and faults that were obtained by seismic data. One fault that was detected by the proposed strategy were also captured by well. Then both fault models were integrated to a unique model and faults were modeled by deterministic method. <br />The integrated fault model obtained by the proposed strategy revealed the importance of a multi-scale fault model in reservoir engineering. Large faults of the study reservoir showed different zones of fractures in the formation reservoir, while small faults in the same model built a discrete network of fractures which provides canals for fluid movement. The integrated model shows that large faults in the study field are mostly in the center of the reservoir, while small faults are distributed through the edges of the formation reservoir, which could be used for further investigation of locating for production and/or injection wells.شناسایی و مطالعه گسلها در مخازن هیدروکربنی، اهمیت ویژهای در مراحل ازدیاد برداشت و توسعه میدان دارد. در بررسی ساختارهای با زمینشناسی پیچیده، تفسیر گسلها با عدمقطعیت بالایی همراه خواهد بود. روشهای متعارف تفسیر و مدلسازی گسلها در دادههای لرزهای علاوه بر نیاز به دانش زمینشناسی مفسر که خود میتواند بهعنوان منشأ عدم قطعیت باشد، فرآیندی بسیار دشوار و وقتگیر است. بدینمنظور در این مطالعه یک استراتژی خودکار و ترکیبی بهمنظور افزایش دقت و سرعت مدلسازی گسلها و شکستگیها در داده لرزهای معرفی میشود. گسلها بهطور معمول با استفاده از نشانگرهای لرزهای تفسیر میشوند. بهمنظور تفسیر گسلهای میدان مورد نظر در این تحقیق، ابتدا نشانگرهای آشفتگی، واریانس، انحنا و الگوریتم ردیابی مورچه از دادههای لرزهای استخراج شد. از بین نشانگرهای موجود، نشانگرهای آشفتگی، واریانس و انحنا بهطور واضح گسلهای بزرگمقیاس را مشخص کردند. گسلهای کوچکمقیاس که شناسایی آنها در دادههای لرزهای دشوار است، بهکمک الگوریتم ردیابی مورچه مدلسازی شدند. بهکارگیری روشهای بیانشده در تفسیر ساختاری مخزن در کنار مدلسازی قطعی گسلها بهروش ترکیبی بر روی دادههای لرزهای، نشاندهنده شناسایی و تفسیر بهتر گسلها با استفاده از استراتژی پیشنهادی و رویکرد ترکیب روشهای موجود بود. نتایج حاصل از تفسیر چند نشانگری و همچنین مدلسازی گسلها در میدان مورد مطالعه، انطباق خوبی با اطلاعات زمینشناسی نشان داد. لذا میتوان پیشنهاد داد استراتژی بهکار گرفتهشده در مدلسازی و استفاده از یافتههای مطالعات چند نشانگری میتوانند بهمنظور افزایش دقت در مطالعات ساختاری مخزن، مورد استفاده قرارگیرند.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Investigation of sensitivity to noise in the three-dimensional displacement field retrieval problem, generated by radar interferometry (Case study: Sefidsang and Ezgeleh earthquakes of 21 March and 12 November 2017, respectively)بررسی حساسیت به نویز مسأله بازیابی میدان جابهجایی سهبعدی حاصل از تداخلسنجی راداری (مطالعه موردی: بهترتیب زلزلههای 16 فروردین و 21 آبان سال 1396 سفیدسنگ و ازگله)971157473710.22059/jesphys.2020.287063.1007149FAسید ساسانباباییدانشجوی دکتری، گروه ژئودزی، دانشکده مهندسی نقشهبرداری، دانشگاه صنعتی خواجهنصیرالدین طوسی، تهران، ایرانمسعودمشهدی حسینعلیدانشیار، گروه ژئودزی، دانشکده مهندسی نقشهبرداری، دانشگاه صنعتی خواجهنصیرالدین طوسی، تهران، ایران0000-0001-9428-366Xسمیعسمیعی اصفهانیاستادیار، دانشکده مهندسی نقشهبرداری و اطلاعات مکانی، پردیس دانشکده های فنی، دانشگاه تهران، تهران، ایرانJournal Article20190918In recent decades, Interferometric Synthetic Aperture Radar (InSAR) technology has been an efficient tool in quantitatively measuring of the earth's deformation, influenced by natural and human factors, such as the overexploitation of water from underground aquifers, mining, subsidence, earthquake, and landslide. However, in the nature of the displacement measurement in the satellite's line of sight (LOS) in this technology, the possibility of extracting a three-dimensional displacement field has faced challenges. Especially in the study of many tectonic phenomena requiring a comprehensive understanding of the three-dimensional displacement components. Therefore, at least three independent radar geometries or InSAR-derived LOS displacements are always needed to solve the problem of retrieval of the three-dimensional (3D) displacement field. However, the polar geometry of imaging radar satellites is such that the contribution of the displacement and effect of the noise of the observations on the estimated parameters (Three-dimensional components) will be different, even in some cases, the problem will be unstable. Therefore, in this research, the noise sensitivity of the three-dimensional displacement field retrieval problem in independent and differential radar geometries is investigated and also based on the orbit overlapping method in the Sentinel radar satellite, using simulated and real data, the three-dimensional displacement of the Sefidsang and Ezgeleh earthquakes of 21 March and 12 November 2017 respectively is retrieved and the efficiency of this method is evaluated. In fact, in this study, considering the importance of knowing and measuring the components of the 3D surface displacement field, the problem of three-dimensional displacement field retrieval was investigated using a combination of independent radar geometries. Then, according to the variance-covariance matrix structure of the problem and the principal component analysis (PCA) method, the sensitivity of recovering each component of the displacement field to the input data noise by taking measurements of three independent radar geometries was discussed. The results show that the north-south displacement component has the highest sensitivity to the input data noise and has the least contribution of displacement along with the satellite LOS. Then the east-west and up-down components have approximately the same sensitivity to noise, although, for some specific incidence angles, the sensitivity to noise for the up-down component will be increased. Also, the condition number of the design matrix in the 3D field retrieval problem show that in most cases (except when the incidence angles of the two geometries are equal or have very slight differences), it is a well-established and stable problem and there is no need to solve it with regularization method. In the second part of the paper, remembering that in the Sentinel radar satellite, each sub-swath is imaged at different angles (with a difference of about 10 degrees), so the concept of overlap between the orbits (at least three different geometries) can be used to retrieve the 3D displacement field in most regions. The feasibility and efficiency of this method were evaluated with real and simulated data. The results showed that in the absence of noise components, the orbit overlap interferometry (OOI) method could be well used in 3D field reconstruction.در دهههای اخیر فناوری تداخلسنجی راداری ابزاری کارا را برای اندازهگیری کمی تغییرشکل زمین، تحتتأثیر عوامل طبیعی و انسانی نظیر فرونشست، زلزله، زمینلغزش، برداشت بیرویه از سفرههای آب زیرزمینی و معدنکاری فراهم کرده است. با این وجود ماهیت اندازهگیری جابهجایی در راستای خط دید ماهواره در این فناوری، امکان استخراج میدان جابهجایی سهبعدی سطح زمین مخصوصاً در مطالعه بسیاری از پدیدههای زمینساختی که نیازمند درک جامعی از مؤلفههای جابهجایی سهبعدیشان است را با چالش مواجه میکند، لذا همواره حداقل سه هندسه مستقل راداری نیاز است تا حل مسأله بازیابی میدان جابهجایی سهبعدی امکانپذیر شود. با این حال هندسه قطبی تصویربرداری ماهوارههای راداری بهنحوی است که سهم جابهجایی و تأثیر نویز مشاهدات بر پارامترهای مجهول (مؤلفههای سهبعدی) متفاوت میشود و حتی در برخی از موارد مسأله ناپایدار خواهد شد. لذا در این تحقیق حساسیت به نویز مسأله بازیابی میدان جابهجایی سهبعدی در هندسههای مستقل و متفاوت راداری بررسی و همچنین براساس روش همپوشانی بین مدارها در ماهواره راداری سنتینل، با استفاده از دادههای شبیهسازیشده و واقعی میدان جابهجایی سهبعدی زلزلههای بهترتیب 16 فروردین و 21 آبان سال 1396 سفیدسنگ و ازگله بازیابی میشود و کارایی این روش مورد ارزیابی قرار میگیرد.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Investigation of the Effect of Atmospheric Correction (DOS) On Water-Vegetations Indexes Mapping (Case Study: South Wetlands of Lake Urmia)بررسی اثر تصحیح جوی تفریق شیء تیره (DOS) بر نقشه شاخصهای آبی- گیاهی (مطالعه موردی: زمینهای مرطوب جنوب دریاچه ارومیه)1171287473410.22059/jesphys.2020.286445.1007143FAوحیدمحمدنژاد آروقاستادیار، گروه جغرافیا، دانشکده ادبیات و علوم انسانی، دانشگاه ارومیه، ارومیه، ایرانJournal Article20190814Wetlands comprise roughly 6–9 percent of the Earth’s surface. The role of wetlands in maintaining environmental quality includes the storage of global terrestrial carbon. In addition, they influence many aspects of ecology, economy and human welfare. Furthermore, wetlands act as an oasis in an urban area which is important in the reduction of surrounding surface air temperature. Changes in the spatial distribution of wetlands (croplands, forests, water bodies and rivers), either by natural factors or anthropogenic activities could significantly affect the ecosystem. Satellite imagery enables us to monitor short-and long-term changes in wetlands and its vegetation density. Due to the fact that the electromagnetic waves reaching the satellites pass through the Earth's atmosphere, the reflections recorded by the sensor of these satellites do not really reflect the phenomena of the Earth's surface. By applying some corrections on the images, it is possible to convert them to Top Of Atmosphere reflectance values (TOA) and the Earth's surface reflections (BOA) ones. In this paper, we have reviewed and compared the results of extraction of wetlands and water body using raw and atmospheric corrected images of Sentinel 2 in south of Lake Urmia. <br />The study area includes wetland and agricultural lands of southern Urmia Lake. Due to the existence of two large Zarrineh and Simineh rivers in the region as well as its very fertile soil, agriculture has expanded rapidly. The main data of this study is satellite images of Sentinel 2 (spring 2019). The dark object subtraction (DOS) is one of the methods of atmospheric correction of satellite images, which with a partial fraction of the dark object's reflection of the whole image, it makes an atmospheric correction of the satellite image. In this paper, this method has been used for atmospheric correction. In fact, a copy of the raw satellite image of the study area was made and the atmospheric corrections were applied. Then the results were compared with the raw images. In order to compare two raw and corrected images, it was attempted to separate the wetlands (rivers, ponds, wetlands) from non-moisturizing lands, so that the effect of atmospheric correction on the ground reflection could be observed. For this purpose, NDWI2 MNDWI, NDTI and SAVI indexes have been used in this paper. <br />To compare the effect of atmospheric correction on Sentinel satellite images, the image of the study area was first provided and entered into the QGIS software for atmospheric correction. Then, using a combination of short infrared, near-infrared and green bands, the extraction and classification of wetlands, water bodies and vegetation cover density was made by SNAP software. Due to the lack of ground control points, the images were sampled by the ArcMap software and verified by using google earth images. Three precision coefficients were used to check and compare the accuracy of raw data with the atmospheric corrected data. In order to compare the accuracy of the outputs, Kappa coefficients, users’ accuracy and producers’ accuracy were calculated using the ArcMap software. The MNDWI and NDTI indices are the best indicators for raw images and for corrected images, to extract wetlands and water bodies. Kappa values of these indicators are above 0.9 and also users’ accuracy and producers’ accuracy are above 96%. Among the four above-mentioned indicators, the NDWI2 index has the lowest accuracy as well as the minimum Kappa coefficient. The results show that corrected images have high accuracy in extracting and displaying wetlands and water bodies. The area of the wetlands and water bodies to be redirected from corrected images is closer to actual areas. The actual area in the SAVI index is 25.15 square kilometers and the redistributed area of raw and corrected images are 25.71 and 25.38 km<sup>2</sup>, respectively. The actual area in the NDWI2 index is 180 km<sup>2</sup>, with a corrected area of 178.93 square kilometers. For other indicators, NDTI and MNDWI, the actual areas are 10.37 and 29.5 km<sup>2</sup>, respectively. In general, it can be concluded that atmospheric corrected images using the DOS method show better results in showing wetlands and water bodies areas. <br />The results of this paper show that the application of atmospheric corrections to the Sentinel 2 images can increase the accuracy of the extraction of wetlands and water bodies areas and even other landcovers. Considering the four indicators and extracting the zones from raw and atmospheric corrected images, it was determined that, firstly, MNDWI and NDTI indices are the best indicators for extracting wetlands and water bodies in the south of Lake Urmia. Secondly, among these two indicators, the data from the corrected atmospheric images have high precision coefficients than raw images. Therefore, it can be said that in estimating the wetlands and water bodies using Sentinel images 2, these images must be corrected using different methods to minimize their error of representations.در مقاله حاضر بهبررسی و مقایسه نتایج حاصل از استخراج پهنههای مرطوب و آبی جنوب دریاچه ارومیه با استفاده از تصاویر خام و تصحیح جوی شده ماهواره سنتینل 2 پرداخته شده است. بدینمنظور تصویر ماهواره سنتینل 2 مربوط به بهار سال 2019 دریافت شد. با توجه به اینکه هدف مقایسه اثر تصحیحات جوی روی تصاویر است، تصویر مورد نظر با استفاده از روش تفریق شیء تیره در قالب نرمافزار QGIS تصحیح شد. سپس بهمنظور استخراج پهنههای مرطوب و آبی از دو تصویر خام و تصحیحشده، چهار شاخص NDWI2، MNDWI، NDTI و شاخص SAVI با استفاده از نرمافزار SNAP تهیه و مورد مقایسه قرار گرفت و هشت نقشه مختلف تهیه شد. این چهار شاخص بهمنظور استخراج پهنههای مرطوب، آبی و پوشش گیاهی طراحی و توسعه پیدا کردهاند. بهمنظور مقایسه دقت خروجیها نیز از ضرایب کاپا و دقت تولیدکننده و دقت کاربر استفاده شد. نتایج نشان میدهد که در بین این چهار شاخص، شاخصهای MNDWI و NDTI، با ضرایب کاپای بالا بهترین عملکرد را دارند. همچنین شاخص NDWI2 با ضریب کاپای 79/0 برای تصویر خام و 83/0 برای تصویر تصحیحشده کمترین دقت را دارد. همچنین مساحت پهنههای مرطوب و آبی استخراج شده از چهار شاخص با مقادیر واقعی مقایسه شد. مساحتهای مستخرج از تصاویر خام و تصحیحشده و مقایسه آن با مساحت واقعی پهنههای مرطوب نشان میدهد که تصاویر تصحیحشده از دقت بالایی برخوردار است.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Study of planetary boundary layer wind field over Qeshm Island, Iranمطالعه میدان باد لایه مرزی سیارهای روی جزیره قشم، ایران1291477473510.22059/jesphys.2020.286563.1007146FAمناضرغامیپوردانشجوی کارشناسی ارشد، گروه علوم غیرزیستی جوی و اقیانوسی، دانشکده علوم و فنون دریایی، دانشگاه هرمزگان، بندرعباس، ایرانحسینملکوتیدانشیار، گروه علوم غیرزیستی جوی و اقیانوسی، دانشکده علوم و فنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران0000-0003-2208-1238Journal Article20190824Since the wind pattern on various activities in islands as well as its effect on other meteorological parameters is important long – term temporal and spatial variations of the wind field are studied. Here, the warmest month (July) and the coldest month (January) 2015, are selected in order to test the sensitivity of low-level wind simulations of the Weather Research and Forecasting (WRF) model to the parameterizations of the boundary layer (PBL), the surface layer (SL) and the land surface (LSM) over Qeshm Island. As this work was focused on the simulation of near-surface and vertical wind profiles, the physical options related to the parameterizations of boundary layer processes (SL, PBL and LSM) that have significance influence for this purpose are validated. Although more physical options are available in the model (for cumulus convection, short and long wave radiation, microphysics and etc.), it is not feasible or necessary to include all the model configuration options in the sensitivity analysis to obtain an efficient model configuration optimization. The model grid comprised of four nested domains at horizontal resolutions of 45, 15, 5 and 1 km respectively. The innermost domain (D4) with 1 km spatial resolution covered the chosen area to simulate PBL wind field over Qeshm island region. The results of the simulations under five different configurations are validated with the observational wind speed data of Qeshm Airport and Marine Qeshm Stations. The results demonstrate that in both episodes, the ACM2 boundary layer scheme has presented the best performance in combination with the Pleim - Xio surface layer and the Noah land surface schemes because it considers vertical mixing both local and non-local in simulation of planetary boundary layer wind structure. The simulations of WRF are sensitive to warm and cold seasons as well as selected parameterizations. After selecting the appropriate configuration, the simulation of the wind field for one year was carried out to investigate the low level wind field, the vertical structure of the boundary layer wind and the impact of the land mask distribution on and around the Qeshm Island. These simulations indicate higher wind speed in spring and summer and the roughness of the island causes a low level wind convergence, then <em>turn</em> to the <em>left</em> on the Strait of Hormuz with decreasing wind speed. Monthly average of the wind direction during the daytime of reference month of each season are generally simulated to be southwesterly (January, April, July, October) and during the nights of January and July it is southerly to southeast and in April and October it is simulated southwesterly. The direction of the wind has significant variations at sunrise and sunset due to changes in regional scale forcing and baroclinicity behavior between the sea and the coast. Surface roughness in coastal areas, strait narrowing and sea breeze, enhance the low-level jet during summer and spring middays at <em>altitudes </em>of about 180 to 200 meters. In other words, we can say these low-level jet (Shamal winds) during summer and spring occurs as a result of the interaction of two pressure systems; the heat low pressure cell (low level cyclone) over Iran and a semi-permanent high over northwestern Saudi Arabia and it acquires some convergence because of the these factors.نظر به اهمیت الگوی باد بر فعالیتهای متعدد در جزایر و همچنین تأثیر آن بر سایر پارامترهای هواشناسی، رفتار زمانی و مکانی بلندمدت میدان باد تراز پایین مشاهداتی روی جزیره قشم مطالعه شد. بهمنظور حساسیتسنجی شبیهسازیهای عددی باد تراز پایین بهوسیله مدل WRF، پارامترسازی لایه مرزی و لایه سطحی روی جزیره قشم، در ماه منتخب از فصل گرم (جولای) و ماه منتخب از فصل سرد (ژانویه) برای سال 2015 بررسی شدهاست. نتایج شبیهسازیها در پنج پیکربندی مختلف با سرعت باد مشاهداتی ایستگاه قشم فرودگاهی و قشم دریایی اعتبارسنجی شدهاست و نتایج نشان میدهد که در هر دو ماه طرحواره لایه مرزی ACM2 بهعلت اینکه اختلاط قائم را هم بهصورت محلی و هم غیرمحلی در نظر میگیرد و در فصل گرم همرفت را بهتر از دیگر طرحوارهها لحاظ میکند در ترکیب با طرحواره لایه سطحی Pleim-Xio و پارامترسازی سطح زمین Noah شبیهسازی بهتری از سرعت و جهت باد تراز پایین ارائه میکند. پس از انتخاب پیکربندی مناسب، شبیهسازی میدان باد بهمدت یک سال (2015) بهمنظور بررسی الگوی باد جزیره قشم، ساختار قائم باد لایه مرزی و تأثیر جزیره بر روی میدان باد لایهمرزی منطقه به انجام رسید. نتایج بیانگر آن است که سرعت باد در فصول بهار و تابستان از مقادیر بالاتری برخوردار است و زبری و پسای جزیره باعث کاهش سرعت باد، رخداد همگرایی و چرخش میدان باد بر روی تنگه هرمز میشود. نسیم دریا و زبری سطح در مناطق ساحلی باعث تقویت رودباد تراز پایین در حین روز و در ارتفاعهای 180 تا 200 متر شدهاست.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Climatology of the Total Electron Content (TEC) Derived from GNSS Station Networkمطالعه اقلیمشناختی محتوای الکترون کلی (TEC) یونسپهری با استفاده از دادهای شبکهبندی شده ایستگاههای GNSS1491577473810.22059/jesphys.2020.287365.1007151FAمحمدجغتاییاستادیار، گروه فیزیک فضا، دانشکده فیزیک، دانشگاه یزد، یزد، ایران0000-0002-4639-4880نیلوفرجویندهدانشجوی کارشناسی ارشد، گروه فیزیک فضا، دانشکده فیزیک، دانشگاه یزد، یزد، ایرانمحمدحسینمعماریاناستادیار، گروه فیزیک فضا، دانشکده فیزیک، دانشگاه یزد، یزد، ایرانJournal Article20190826The Earth’s ionosphere is one of the important layers of the atmosphere, starting from 60 kilometers extending up to about 1000 kilometers. Even though the layer contains less than 1% of the total mass of the atmosphere; however, it has very important effects on the solar radiation and transmission of radio waves. The ionosphere is formed under effect of solar extreme ultraviolet (EUV), solar X-ray radiation, and electron precipitation of solar winds. The lower atmosphere also contributes to the variability of the ionosphere. In other words, ionosphere is under effects of both lower atmosphere dynamics from below and solar radiation from above boundary. Therefore, the amount of changes of particles in the ionosphere depend largely on many parameters such as time, radiation pattern, Sun-Earth geometry, ion chemistry, and solar activity. Sun’s variability is most important origin of the ionosphere long term change, so that the amount of change in the ionosphere layers depends largely on the time and mode of radiation, the Earth-Sun status, and the solar activity. Variety of periodic and nonperiodic variations should be considered in the ionosphere, which makes serious impacts on satellite and ground communication, precise navigation and radio broadcasting. In this research, the relationship between solar activity and total electron content (TEC) is investigate with gridded global TEC data. <br />Total electron content (TEC) data are important ionosphere parameter that can be derived from time delay of radio wave transmitted from satellite to ground base station. The maps of TEC are given with the resolution of 5<sup>o</sup> in longitude and with the resolution of 2.5<sup>o</sup> in latitude, 12 times every day (one map in every two hours at UTC time). In the other word, each IONEX file includes 13 maps in which one map has overlap with next day. Longitude ranges from -180 to 180 degrees that includes 73 points resolution. Latitude ranges from -87.5 to 87.5 degrees that indicates 71 points with the resolution of 2.5<sup>o</sup>. We use F10.7 index for determination of solar activity. This parameter is indicative of radio emittion of sun in 10.7 cm radio wave. This index has a good correlation with sun spot number and nowadays it is used in many research as solar activity parameter. <br />In this investigation, we used 19-years data IONEX for the period 1999 – 2017 for both 23 and 24 solar cycles. At first, we calculated zonal mean of data (in all longitudes, for every latitude) every day, then for every month and finally for every year. We had the mean data of TEC for every day, month and year of these 19 years. In the 23 solar cycle that began in August 1996 and continued to December 2008, minimum amount of TEC was 14 TECU in 2008, and maximum amount was about 57 TECU in 2000 and 2002. In this solar cycle, the time gap between minimum and maximum was 6 to 8 years. In the current solar cycle, solar cycle 24, with minimum amount of TEC was 14 TECU in 2009 and with maximum 44 TECU in 2014. The time gap between both extremes was about 5 years. In all years, maximum amount of TEC was in low and middle latitude, and minimum was in high latitude. Results indicated that maximum TEC was in southern hemisphere in December, January and February. In June, July and August, maximum TEC is located in northern hemisphere. Maximum amount of TEC was in March, April and October, and minimum was in June, July and August. It seems that maximum position and value depend on solar declination, Earth-Sun position and geometry.لایه یونسپهر از لایههای مهم جو زمین است که در اثر جذب تابش ماوراءبنفش و ایکس خورشیدی و برخورد ذرات باردار با اتمها و مولکولهای جو زمین و برهمکنش فوتوشیمیایی بین ترکیبات آن تشکیل میشود. الکترونهای آزاد در این لایه بر مسیر امواج رادیویی تأثیر میگذارد و هرگونه اختلال احتمالی در این لایه، تأثیر جدی در ارتباطات ماهوارهای، ارتباطات دقیق ناوبری و ارتباطات دوربرد میگذارد. پس شناخت مقادیر میانگین و توزیع نصف النهاری مقادیر الکترونهای آزاد کمک شایانی به شناخت پریشیدگی و اختلالهای احتمالی آن میکند. یک روش پذیرفتهشده در تحقیق ساختار زمانی و فضایی و تغییرپذیری الکترونهای آزاد یونسپهر، برآورد محتوای کلی الکترون (TEC) است. TEC مجموع الکترونهای موجود در استوانهای با سطح مقطع یک متر مربع است که در مسیر ماهواره تا گیرنده زمینی محاسبه میشود.<br /> در این پژوهش برای بررسی پریشیدگیهای یونسپهری از دادههای جهانی و شبکهبندیشده ایستگاهی GNSS، برای بازه زمانی 1999 تا 2017 استفاده شدهاست. از دادهها میانگین سالانه و ماهانه برای 19 سال گرفته شدهاست. همچنین برای فعالیت خورشیدی از شاخص F10.7 استفاده شده است که تابش خورشید در طولموج cm 7/10 است. در پژوهش انجامشده، روند تغییرات TEC، وابستگی زیادی به تغییرات چرخه خورشیدی دارد. با بررسی مقادیر TEC مشاهده شد که مقدار TEC در ماههای آوریل و مارس واکتبر بیشینه است در حالیکه در ماههای جولای و جون کمینه مقادیر را دارد. بهبیان دیگر مقادیر TEC در اعتدالین بیشتر و در انقلاب تابستانی کمترین مقدار را داراست.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420Seasonal variations of the water column structure and estimation of the mixed layer depth based on the temperature using threshold method in Babolsar and Ramsar regionsتغییرات فصلی ستون قائم آب و تخمین عمق لایه آمیخته بر پایه دما با استفاده از روش آستانه در منطقه بابلسر و رامسر1591747473910.22059/jesphys.2020.286089.1007154FAفاطمهجاننار فریدوندانشجوی کارشناسیارشد، گروه فیزیک دریا، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، نور، ایرانسمیهنهاوندیان اصفهانیاستادیار، گروه فیزیک دریا، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، نور، ایران0000-0002-8763-4983نعمتاللهمحمودیاستادیار، گروه علوم و مهندسی شیلات، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، نور، ایرانJournal Article20190903The physical processes play an important role on the biochemical phenomenal in the seas and oceans. The Mixed layer is the surface layer in which due to the air-sea exchange, the physical parameters such as temperature, salinity and density are almost constant. The layer beneath the mixed layer where the gradient of the physical parameters is large, is called thermocline, halocline and pycnocline, respectively in the temperature, salinity and density profiles. The deep part is the deepest layer where the physical parameters are nearly constant. Because the mixed layer acts as an interface between the atmosphere and deeper layers of the sea, its depth is not only influenced by weather but also strongly impacts the climate change. The mixed layer depth (MLD) has an important role in biochemical processes, gas exchanges, transferring heat, mass and momentum between the atmosphere and the sea. In this study seasonal and spatial variations of the MLD as well as the temperature and the salinity profiles are investigated in the Southern Caspian Sea in the Babolsar and Ramsar regions based on the Conductivity-Temperature-Depth (CTD) measurements conducted during fall, spring and summer 2012. According to the observations, despite the fact that the range of variations of the temperature and the salinity in the Babolsar and Ramsar is comparable, during the spring the salinity fluctuation inside the halocline is larger in Babolsar. It is worth to mention that the salinity fluctuates highly inside the halocline, contrary to the classic definition that the salinity increases with depth inside the halocline. The MLD has been estimated using the threshold method with four different threshold values (0.05, 0.5, 1 and 1.25 (°C)). In order to avoid erroneous estimation of MLD (very extreme values), each temperature profile is also carefully examined by visual investigation. Then visual inspection and statistical analysis approaches have been employed to assess the most appropriate threshold value. To this end, calculated MLDs using different threshold values have been plotted against visual MLDs. Large number of points away from line of 45° shows that the calculated MLDs using related threshold value is biased against visual MLDs. While the largest number of points around 45° line demonstrates that the MLDs estimated by both methods are similar to each other and the considered threshold value is an appropriate one. The results reveal that the seasonal hybrid algorithm with threshold values of 0.5 (°C) for fall, 1 (°C) for summer, and 1.25 (°C) for spring gives the best estimation for the MLDs. The calculated MLDs show that the MLD is maximum in the fall and minimum in the spring which is in agreement with Jamshidi et al. (2010). The reason for a deeper MLD in the summer compared to the spring can be related to the high evaporation during this season, which leads to salinity increase at the surface and augmentation of the convection. Spatial comparison of the MLDs in Babolsar and Ramsar regions shows that the MLD is slightly deeper in Ramsar and the gradient of the temperature just below the mixed layer in Ramsar is larger compared with that in Babolsar. The vertical structure of the mixed layer can be sub-divided into three principle types: the classical, stepwise and inclined types. The classical and stepwise type profiles are similar to the results reported by Tai et al. (2017) conducted in the principle northern South China Sea. The classical type has quasi isothermal mixed layer followed by a steep thermocline which is the most observed in the fall. In the stepwise type, the temperature decreases inside the mixed layer with one or more small steps before drastical decrease in the seasonal thermocline. The stepwise type has been observed more often during the summer. Finally in the inclined type which is occurred in the spring, the MLD’s temperature gently decreases with depth followed by an abrupt decrease of the temperature in the thermocline.در این تحقیق تغییرات فصلی و مکانی عمق لایه آمیخته و ساختار قائم دما و شوری در آبهای نزدیک به ساحل دریای خزر در منطقه بابلسر و رامسر در سه فصل بهار، تابستان و پاییز سال 1391 با استفاده از اندازهگیریهای CTD مورد بررسی قرارگرفت. با وجود مشابهت محدوده تغییرات دما و شوری در دو منطقه اندازهگیری، نوسانات شوری در بابلسر بالاتر از رامسر و در فصل بهار شوری در لایه سطحی در رامسر بهشکل قابلتوجهی کمتر از بابلسر است. هالوکلاین تقریباً همعمق ترموکلاین قرار داشته و بهشکل نوسانات شدید شوری خود را نشان میدهد. برای تخمین عمق لایه آمیخته از روش آستانه و با آستانههای (C˚) 05/0، (C˚) 5/0، (C˚) 1 و (C˚) 25/1 استفاده شد. بدون در نظرگرفتن تفکیک فصلی مقدار آستانه (C˚) 25/1 عمق لایه آمیخته را بهتر از مقادیر دیگر آستانه تخمین زد. در نهایت الگوریتم ترکیبی بهتفکیک فصل، با آستانه (C˚) 25/1 در بهار، 1 (C˚) در تابستان و مقدار آستانه (C˚) 5/0 در فصل پاییز برای تخمین عمق لایه آمیخته مورد استفاده قرار گرفت. کمینه و بیشینه عمق لایه آمیخته بهترتیب در بهار و پاییز مشاهده شد و طبق نتایج بهدستآمده، ساختار قائم لایه آمیخته را میتوان به سه نوع، کلاسیک در پاییز، شیبدار در بهار و پلهای در تابستان تقسیم کرد.موسسه ژئوفیزیک دانشگاه تهرانفیزیک زمین و فضا2538-371X46120200420A case study on air pollution diffusion using data from the Bushehr meteorology towerمطالعه موردی پخش آلایندهها با استفاده از دادههای برج هواشناسی بوشهر1751897474110.22059/jesphys.2020.290390.1007172FAمحمدمرادیدانشیار، پژوهشگاه هواشناسی و علوم جو، تهران، ایران0000-0002-5356-8578عباسرنجبر سعادتآبادیدانشیار، پژوهشگاه هواشناسی و علوم جو، تهران، ایرانپرویزرضازادهمشاور پیشبینی، سازمان هواشناسی کشور، تهران، ایرانJournal Article20191009A serious problem which threatens life in metropolises is air pollution released in boundary layers in local and regional scales due to human activities. Pollutants accumulate in specific meteorology conditions in cities. Air stagnation, temperature inversion, cold air damming, topography, mountain and valley winds, urban buildings wakes and atmospheric stability are metrological factors. These conditions are recorded in most air pollution episodes in the world. Many researchers have used Gaussian distribution model for analyzing the manner of pollutants distribution in long term. In these works not only Gaussian model for distribution and deposition has been analyzed but the meteorological conditions for running the model and estimation of coefficients of model have also been analyzed. <br />In this article the potential air pollution in Bushehr city is studied by the Gaussian diffusion model to calculate the horizontal and vertical standard deviations of the model outputs, using the Hosker-Smith formula. The plume rise height is calculated by Briggs method and the height of the mixed layer by the Heffter algorithm. For the model run we used 2016 archived data from the 100m height Bushehr meteorology tower. In this research for winter the months of December of 2015, January and February of 2016 are considered, for spring, March, April and May, for summer June, July and August and for fall, September, October and November are considered. The annual covers from January to December of 2016. <br />Regarding the presented conditions, Gaussian distribution model run for a hypothetical point source in open rural area. The process is as following: <br />1- Data of direction and speed of wind in height of 10 to 100 meters are analyzed in different days of 2016 and December of 2015 and after omitting doubtful data, the average values of daily, monthly, seasonal and annual wind field are extracted. <br />2- These data were used in calculation of average value of multiplying classified wind speed by normalized coefficient instability classes. <br />3- Data of radiation and temperature in different levels of meteorology tower are analyzed and after omitting the noises and attaining adequate accuracy, vertical gradient of temperature was calculated and regarding the wind speed, the stability classes for day and night were calculated. <br />4- Vertical and horizontal standard deviations were calculated based on Hosker-Smith equations. <br />5- Height of plume rise was calculated for estimating effective height by using chimney inner diameter, gas discharging velocity and its temperature in different stability classes according to Briggs method. <br />6- Mean length of mixed layer was calculated by using long term data of nearest upper air station to Bushehr meteorology tower. <br />Analysis of wind field at the height of 100 meters of Bushehr meteorology tower showed that in spring the abundance of northwesterly wind is 19.5%, north wind 11.4% and northeasterly wind is 10.4%. In summer abundance of north- northwesterly wind is 15.6% and northwesterly wind is 15.3%. In fall the abundance of northerly wind is 17.4%, northwesterly 14.5%, north- northwesterly 14.5% and north-northeasterly wind is 12.3%. In winter abundance of northerly wind is 31.6%, north- northwesterly 17.2% and north-northeasterly is 15.6%. The annual abundance in 2016 of northerly wind is 18.3% and north-northeasterly wind is 11%. <br />The vertical and horizontal standard deviations are estimated in different stability and instability classes. Calculating the horizontal standard deviation by different methods in all classes, does not make significant difference is. Calculation of vertical standard deviation by Hosker-Smith method has a significant difference in all classes. It is very similar to Briggs method in very severe instability classes and by increasing the distant from pollutant source, its quantity slightly increases. In stability classes, this method gives higher values in comparison with the others. <br />The model results show that hypothetical pollutants distribute in winter toward south, in spring southeast and Southwest, in summer to southeast and north and in fall to southeast, south and southwest. The annual distribution is toward south and southeast. The maximum values of this quantity in spring, summer and fall spread up to 2km along the mentioned directions but the maxima in summer spreads up to 3km from the source. Annual maxima do not extend more than 2 km from the source. <br />Analyzing the results and adjusting them with the results of 100-meter meteorological tower seasonal wind rose, results show that, how perfectly simplified Gaussian model depicts the manner of pollutants distribution. The model results indicate that the hypothetical pollution dispersion in winter time around the Bushehr meteorology tower is toward south, while in summer the dominant dispersion is toward southeast and north. The difference in dispersion direction between summer and winter is due to stronger sea breeze in summer. Some northward emission may exist due to southerly winds in the annual wind regime.این مقاله به پتانسیل آلایندگی در بوشهر بهکمک مدل پخش گاوس پرداخته است. در این پژوهش انحرافمعیار قائم مدل بهسبب نبود دادههای سرعت اصطکاکی و طول مونیون-ابکوف، از روابط هاسکر-اسمیت، ارتفاع خیزش پلوم از روش بریگز و ارتفاع لایه آمیخته از روش هیفتر بهدست آمد. برای تعیین کلاسهای پایداری، از دادههای تابش خورشیدی و گرادیان قائم دما و برای اجرای مدل، از دادههای برج هواشناسی بوشهر در سال 2016 استفاده شده است. <br /> نتایج حاصل از اجرای مدل نشان داد که در موقعیت برج هواشناسی بوشهر در فصل زمستان، آلایندههای فرضی از شمال بهسوی جنوب برج پخش میشود در حالیکه نحوه پخش آنها در تابستان از شمالغرب به جنوبشرق و همچنین از جنوب بهسوی شمال است. این تفاوت میتواند بهسبب قوی بودن نسیم دریا به خشکی در تابستان و ضعیف بودن آن در زمستان باشد. قسمتی از آلاینده فرضی نیز بهدلیل وجود مؤلفه جنوبی باد سالانه، بهسوی شمال پخش میشود. در فصلهای بهار و پاییز نیز نحوه پخش آلایندهها متفاوت است. در فصل بهار که باد غالب در ارتفاع 100 متری برج هواشناسی بوشهر شمالغربی است، آلایندهها بیشتر بهسوی جنوبشرق پخش میشوند در حالیکه در فصل پاییز فراوانی باد شمالی بیشتر است و آلایندههای فرضی بیشتر بهسوی جنوب پخش میشوند. همچنین بررسی روشهای برآورد ضرایب مدل گوس نشان داد که روابط هاسکر-اسمیت با در نظرگرفتن طول زبری سطح برای منابع نقطهای که فاقد دادههای سرعت باد اصطکاکی و طول مونیون-ابکوف هستند، روش مناسبی است.