تحلیل همدیدی رخداد حفره‌های کوچک ازن در منطقه ایران مرکزی (اصفهان)

نویسندگان

1 دانشجو

2 دانشگاه تربیت مدرس

3 مؤسسۀ ژئوفیزیک دانشگاه تهران

چکیده

این تحقیق با بهره‌گیری از داده‌های روزانه ازن پوشن‌سپهر روی اصفهان که از طریق سنجنده‌های زمینی بروئر و ماهواره TOMS و OMI از سال 2001 تا 2011 اندازه‌گیری شده، جهت شناسایی و مطالعه شدیدترین رخداد کاهش ازن (حفره کوچک ازن) بکار گرفته شد. با بکارگیری آستانه منفی دوبرابر انحراف معیار ماهانه، 25 رخداد حفره‌ کوچک ازن ‌در طول دوره مورد مطالعه نمایان شد که بیشترین تمرکز آنها با شانزده و هفت مورد به ترتیب در پاییز و زمستان اتفاق افتاده است. دامنه ناهنجاری منفی آنها نیز از عمق 24% در زمستان تا 6% در تابستان در نوسان بوده است. این بررسی نشان داد که در مواقع شکل‌گیری حفره‌های کوچک ازن، ارتفاع وردایست (TH) به تراز بالاتر جو هدایت شده و همزمان دما و فشار آن نسبت به میانگین درازمدت کاهش محسوسی می‌یابد. نقشه‌های سطوح زمین‌پتانسیل در ناحیه وردسپهر بالایی و پوشن‌سپهر پایینی (UTLS) مرتبط با دو حادثۀ کاهش شدید ازن روی فلات ایران، پشته عمیقی را روی شمالغربی اروپا که با فرودی در شرق دریای مدیترانه همراهی داشته نشان داده است. علاوه بر الگوی همدیدی مشاهده شده در ناحیه UTLS روی فلات مرکزی ایران که موجب تسهیل در وزش افقی هوای ازن کم از منشأ عرض‌های جنب‌حاره‌ (حادثه 7 ژانویه 2002) و عرض‌های بالا (حادثه 16 اکتبر 2011) شده است، می‌توان به عامل دینامیک دوم که با صعود محلی سطوح هم‌آنتروپی موجب تشدید کاهش ازن پوشن‌سپهر می‌شود همزمان برای شکل‌گیری چنین رخدادهایی مهم قلمداد نمود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The synoptic analysis of ozone mini-hole events over central Iran (Esfahan)

نویسنده [English]

  • Seyyed Shafi Moosavi 1
1
2
3
چکیده [English]

In this study, the daily Total Ozone Column (TOC) measured by the instruments of TOMS (2001) and OMI (2005-2011) satellites and Brewer ground station (2002-2004) is used to investigate the extreme ozone mini-holes over Esfahan. Based on previous reports on validation of the TOC data products, it is found that there is no problem with homogenization of data records, which was provided by the above measuring instruments. Firstly, it is shown that the TOC monthly mean and standard deviation over central Iran depend on the seasonal cycle with maximum values of 298 and 27 DU in winter and minimum values of 270 and 8 DU in summer, respectively. The difference between the maximum and minimum climatological monthly means is 53 DU. Regarding the absolute values of TOC, the maximum (minimum) amplitude is related to the winter season with 169 DU in Feb (summer with 39 DU in Aug). Due to the minus twice standard deviation of the monthly average which is known as the threshold chosen to identify the possible ozone mini-holes, 25 events are detected during the study period with maximum concentrations, of which 16 and 7 cases occurred in autumn and winter seasons, respectively. The most occurrences of ozone mini-hole are seen in 2005 and 2011 with 7 and 6 events, respectively. It is worthwhile to mention that the lowest levels of ozone in Arctic were also seen during the two mentioned years from 2001 to 2011. Nevertheless, no mini-holes were detected for three years 2003, 2004 and 2009. The range of ozone negative anomalies is confined from around 24% in winter (Jan) to 6% in summer (Aug). However, it was reported that ozone mini-holes in some regions have reduced the TOC up to 40% of climatology mean of mid and high latitudes over the northern hemisphere. It is found that during ozone mini-hole events, the Tropopause Height (TH) tends to move upwards (with a maximum of 5.5 km higher than monthly average on 10 March 2008) which in turn leads to decrease in the temperature and pressure of TH. Similar to its seasonal cycle, the low observed values of the tropopause temperature and pressure in summer is stronger than winter season. In general, the ranges of temperature (pressure) in the thermal tropopause during low ozone events becomes from -2.3°C (-27 hPa) in February 2006 to -15.5°C (-115 hPa) in March 2008. However, the mentioned above pattern almost explains the maximum events, the observed ozone mini-holes in January 2002 don not show similar anomalies in TH. It is more probably that low ozone events during the January of 2002 are more related to the meridional transport of air masses with climatology low ozone from the subtropical latitude which is poleward near the tropopause. Backward trajectory analysis also showed that the origins of poor ozone air masses in the spring/summer (autumn/winter) seasons are related to the eastern areas (western areas) of Iran. On 7 Jan 2002 at 16 km altitude (on 16 Oct 2011 at 22km altitude), the lower part of trajectory analysis, is more characterized by horizontal movement of poor ozone air mass from lower latitude (higher latitude). During the two extreme low ozone events over Esfahan which approximately correspond to the deepest events and eventful periods, two broad ridges are seen over coastal line of North-West Europe along with two deep troughs in the eastern-central Mediterranean Sea. The blocking ozone mini-holes over North-West Europe are related to the upward movement of geopotential height in the upper troposphere and lower stratosphere (UTLS) region which is in agreement with both the advection of poor ozone air from the sub-tropical (7 Jan 2002) and the higher latitudes (16 Oct 2011) toward the mid latitudes over central Iran.
 

کلیدواژه‌ها [English]

  • Central Iran
  • Total Ozone Column (TOC)
  • Ozone mini-hole
  • tropopause height (TH)
شرعی پور، ز.، 1391، توزیع قائم اُزن و دما روی اصفهان، پانزدهمین کنفرانس ژئوفیزیک ایران.
 
Alados, I., Gomera, M. A., Foyo-Moreno, I. and Alados-Arboledas, L., 2007, Neural network for the estimation of UV erythemal irradiance using solar broadband irradiance, Int. J. Climatol., 27, 1791-1799.
Allen, D. R. and Nakamura, N., 2002, Dynamical reconstruction of the record low column ozone over Europe on 30 November 1999, Geophys. Res. Lett., 29, 1362, doi:10.1029/2002GL014935.
Anton, M., Cancillo, L., Serrano, A., Vaquero, J. M. and Garcia, J. M., 2007, Ozone mini-hole over southwestern Spain during January 2004: Influnce over ultraviolet radiation, Geo Res., 34, 1-5.
Barriopedro, D., Anton, M. and Garcia, J. A., 2010, Atmospheric blocking signatures in total ozone and ozone miniholes, J. Climate., 23, 3967-3983.
Bojkov, R. and Balis, D., 2001, Characteristics of episodes with extremely low ozone values in the northern middle latitudes 1957-2000, Annales Geophysicae, 19, 797-807.
Hadjinicolaou, P. and Pyle, J., 2004, The impact of Arctic Ozone depletion on Northern Middle Latitudes, interannual variability and dynamical control, J. Atmos. Chem., 47, 25-43.
Hommel, R., Eichmann, K. U., Aschmann, J., Bramstedt, K., Weber, M., Savigny, C., von Richter, A., Rozanov, A., Wittrock, F., Khosravi, F., Bauer, R. and Burrows, J. P., 2014, Chemical ozone loss and ozone mini-hole event during the Arctic winter 2010/2011 as observed by SCIAMACHY and GOME-2., Atmos. Chem. Phys., 14, 3247-3276.
Hood, L. L. and Soukharev, B. E., 2005, Interannual variation of total Ozone at Northern Midlatitudes correlated with stratospheric EP flux and potential vortices, Journal of the Atmospheric sciences., 62, 3724-3740
James, P. M., 1998, A climatology of ozone mini-holes over the northern hemisphere, Int. J. Climatol., 18, 1287-1303.
Koch, G., Wernli, H., Schwierz, C., Staehelin, J. and Peter, T., 2005, A composite study on the structure and formation of ozone miniholes and minihighs over central Europe, Geophys. Res. Lett., 32, L12810, doi:10.1029/2004GL022062.
Krzyscin, J., 2002, Long-term changes in ozone mini-hole event frequency over the Northern Hemisphere derived from ground-based measurements, Int. J. Climatol., 22, 1425-1439.
Martinez-Lozano, J. A., Utrillas, M. P., Nunez, J. A., Tamayo, J., Marin, M. J., Esteve, A. R., Canada, J. and Moreno, J. C., 2011, Ozone mini-holes Valencia (Spain) and their influence on the UV Erythemal radiation, Int. J. Climatol., 31, 1554-1566.
McPeters, R., Kroon, M., Labow, G., Brinksma, E., Balis, D., Petropavlovskikh, I., Veefkind, J. P., Bhartia, P. K. and Levelt, P. F., 2008, Validation of the Aura Ozone monitoring instrument total column ozone product, Journal of Geophysical Research, 113(D15S14), 1-9.
Newman, P. A., Lait, L. R. and Schoerbel, M. R., 1988, The morphology and meteorology of southern hemisphere Spring total ozone mini-hole, Geophysical Research Letters, 15, 923-926.
Orsolini, Y., Eskes, H., Hansen, G., Hoppe, U., Kylling, A., Kyr¨o, E., Notholt, J., van der, A. R. and von der Gathen, P., 2003, Summertime lowozone episodes at northern high latitudes, Quarterly Journal Royal Meteorological Society, 129, 3265-3275.
Seman, N., Teitelbaum, H. and Basdevant, C., 2002, A very deep ozone minihole in the Northern Hemisphere stratosphere at mid-latitudes during the winter of 2000, Tellus, 54A, 382-389.
Sola, Y. and Lorent, J., 2011, Impact of two low Ozone event on surface solar UV radiation over Northeast of Spanish, Int. J. Climatol., 31, 1724-1734.
Son, S. W., Polvani, M. P., Waugh, D. W., Birner, T., Akiyoshi, H., Garcia, R. R., Gettelman, A., Plummer, D. A. and Rozanov, E., 2009, The impact of stratospheric Ozone recovery on tropopause height trends, Journal of Climate, 22, 429-445.
Stick, C., Kr¨uger, K., Schade, N., Sandmann, H. and Macke, A., 2006, Episode of unusual high solar ultraviolet radiation over central Europe due to dynamical reduced total ozone in May 2005, Atmospheric Chemistry Physics, 6, 1771-1776.
United Nation Environment Program (UNEP), 2007, Environmental effects of Ozone depletion and the interaction with climate change, 2006 Assessment, 978-92-807-2821-7, OZO/0947/NA.
Varotsos, C., Cartalis, C. and Valamakis, A., 2004, Long- term coupling between column Ozone and tropopause propertes, J. climatol., 17, 3843-3854.
Werner, R., Valev, D., Atanassov, At., Kostadinov, I., Petkov, B., Giovanelli, G., Stebel, K., Petritoli, A., Palazzi, E., Gausa, M. and Markova, T., 2009, Ozone mini-hole observation over the Balkan Peninsula in March 2005, Advances in Space Research, 43, 195-200.
WMO, 2014, Scientific assessment of Ozone depletion; 2014. Report No. 56, Global Ozone Research and Monitoring Project, Geneva, Switzerland.
WMO, 1992, International meteorological vocabulary WMO/OMM/BMO – No. 182. (Second edn). Secretariat of the World Meteorological Organization–Geneva–Switzerland: Geneva; 784.
UNEP/WMO, 1957, Definition of the thermal tropopause. 195 pp.