مقایسه مدل‌های ژئوپتانسیل جدید در منطقه جغرافیایی ایران از راه تابعک‌های متفاوت میدان گرانی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی نقشه‌برداری، قطب مهندسی نقشه‌برداری و مقابله با سوانح طبیعی، پردیس فنی دانشگاه تهران صندوق پستی 4563-11365

2 سازمان نقشه‌برداری کشور صندوق پستی 1684- 13185

چکیده

پیشرفت‌های اخیر در گرانی‌سنجی ماهواره‌ای، هوایی و زمینی باعث تولید مدل‌های ژئوپتانسیل با توان تفکیک بالا شده است. از آنجا که
این مدل‌ها ژئوپتانسیلی متکی بر مشاهدات گرانیی نوین با تراکم و دقت بالا هستند، منابع با ارزشی، خصوصاً برای بیان طول‌موج‌های بلند و متوسط، به شمار می‌روند و بدین لحاظ تبدیل به بخش‌های اصلی الگوریتم‌های جدید در مدل‌سازی میدان گرانی زمین شده‌اند. با توجه به تنوع نسبتاً زیاد این مدل‌ها، لازم است که کیفیت آنها در مناطق مختلف با مقایسه با مشاهدات گرانی کنترل شود، تا از میان آنها بهترین مدل انتخاب شود. در این مقاله مدل‌های EGM96، PGM2000A، Eigen-cgo1c و Eigen-Grace2s در منطقه جغرافیایی ایران از نظر قابلیت تولید تابعک‌های متفاوت میدان گرانی ارزیابی شده‌اند. برای این منظور از داده‌های مربوط به طول و عرض نجومی، شتاب گرانی و ژئوئید حاصل از GPS/Leveling استفاده شده است. براساس نتایج حاصل از کنترل‌های عددی مدل‌های ذکر شده، مدل EGM96 و تقریباً به‌صورت مشابه مدل PGM2000A نزدیک‌ترین مدل ژئوپتانسیلی به مشاهدات از انواع طول و عرض نجومی، شتاب گرانی و ژئوئید حاصل از GPS/Leveling در منطقه جغرافیایی ایران است.

کلیدواژه‌ها


عنوان مقاله [English]

A comparative study of the recent geopotential models for synthesizing different gravity functional at the geographical region of Iran■

نویسندگان [English]

  • Ali Reza Azmoodeh Ardalan 1
  • Abdol Reza Safari 1
  • Yahya Jamour 2
1 Department of Surveying and Geomatics Engineering, Center of Excellence of Surveying and Disaster Management, University of Tehran
2 National Cartographic Center of Iran
چکیده [English]

Recent progress in the field of satellite, airborne, and surface gravimetry has resulted in geopotential models with high resolution. Since the geopotential models are computed based on dense and highly accurate gravity data, they are valuable sources of information for presentation of long and medium wavelength spectrum of the gravity field in the computational algorithm of modern gravity field modeling techniques. Considering the variety of the geopotential models which are currently available, it is necessary to verify their accuracy in synthesizing the gravity functional so that one can select the best geopotential model for a region of interest. In this study 4 geopotential models, namely:  EGM96, PGM2000A, Eigen-cgo1c, Eigen-Grace2s, are compared for their accuracy in synthesizing gravity functional of the types: (1) astronomical longitude, (2) astronomical latitude, (3) norm of gravity acceleration, and (4) geoid from GPS/Leveling in the geographical region of Iran. Based on the numerical results EGM96 and PGM2000A perform almost the same in synthesizing the aforementioned gravity functionals in the geographical region of Iran.

کلیدواژه‌ها [English]

  • Geopotential models
  • Astronomical longitude
  • Astronomical latitude
  • Gravity acceleration
  • GPS/Leveling
Ardalan, A. A., 1999, High resolution regional geoid computation in the world geodetic datum 2000, based upon collocation of linearized observational functionals of the type GPS, gravity potential and gravity intensity , Ph.D. thesis , Stuttgart University.
Ardalan, A. A., and Grafarend, E. W., 2004, High-resolution regional geoid computation without applying Stokes’s formula: a case study of the Iranian geoid. J. Geodesy, 78, 138-156.
Bode, A., Grafarend, E.W., 1982, The telluroid mapping based on a normal gravity potential including the centrifugal term. Boll Geod. Sci. Aff., 41, 21-56.
Bruns, H., 1878, Die figur der erde. ein beitrag zur europaischen gradmessung. publ kgl Preu ß Inst, Berlin.
Featherstone, W. E., 2002a, Expected contributions of dedicated satellite gravity field missions to regional geoid determination with some examples from Australia. J. Geospatial Eng. 4, 2-19.
Featherstone, W. E., 2002b, Comparison of different satellite altimeter-derived gravity anomaly grids with ship-borne gravity data around Australia, Proceedings of GG2002, Thessaloniki,http://olimpia.topo.auth.gr/GG2002/SESSION4/session4.html.
Featherstone, W. E., and Guo, W., 2001a, A spatial evaluation of the precision of AUSGeoid98 versus AUSGeoid93 using GPS and levelling data, Geomat. Res. Australasia, 74, 75-102.
Featherstone, W. E., Kearsley, A. H. W. and Gilliland, J. R., 1997, Data preparations for a new Australian gravimetric geoid, The Aus. Surv. 42, 33-44.
Featherstone, W. E., Kirby, J. F., Kearsley, A. H. W., Gilliland, J. R., Johnston, G. M., Steed, J., Forsberg, R., and Sideris, M. G., 2001b, The AUSGeoid98 geoid model of Australia: data treatment, computations and comparisons with GPS-levelling data, J. Geodesy, 75, 313-330.
Featherstone, W. E., and Rüeger, J. M., 2000, The importance of using deviations of the vertical inthe reduction of terrestrial survey data to a geocentric datum, The Trans-Tasman Surveyor, 1(3), 46-61 (erratum in The Aus. Surv. 47, 7).
Grafarend, E. W., 1978, Dreidimensionale geodatische Abbildungs-gleichungen und die Naherungsfigur der Erde. Z., Vermess, 103, 132-140.
Grafarend, E. W., 1980, The Bruns transformation and a dual set-up of geodetic observational equations. National Oceanic and Atmospheric Administration, Rep NOS 85, NGS 16, Rockville.
Grafarend, E. W., 2001, The spherical horizontal and spherical vertical boundary value problem-vertical deflections and geoidal undulations-the complete Meissl diagram. J. Geodesy, 75, 363-390.
Grafarend, E. W., Ardalan, A. A., 1999, World Geodetic Datum 2000 , J. Geodesy, 73, 611-623.
Grafarend, E. W., Ardalan, A. A., Sideris, M., 1999, The ellipsoidal fixed-free two-boundary value problem for geoid determination (the ellipsoidal Bruns transform). J. Geod., 73, 513-533.
Heiskanen, W. A., Moritz, H., 1967, Physical Geodesy. Institue of Physical Geodesy, Technical University of Graz, Austria, W. H. Freeman.
Hirvonen, R. A., 1961a, New theory of the gravimetric geodesy. Publ Isostatic Inst, Ann Acad Sci Fenn A3: 1-50.
Hirvonen, R. A., 1961b, The reformation of geodesy. J. Geophys Res., 66, 1471-1478.
Jekeli, C., 1988, The exact transformation between ellipsoidal and spherical harmonic expansions. Manuscr. geodaet. 13, 106-113.
Jekeli, C., 1999 An analysis of vertical deflections derived from high-degree spherical harmonic models. J. Geodesy, 73, 10-22.
Krarup, T., 1969, A contribution to the mathematical foundation of physical geodesy. Internal rep, Geodetic Institute, Copenhagen.
Lemoine, F. G., Smith, D. E., Kunz, L., Smith, R., Pavlis, E. C., Pavlis, N. K., Klosko, S. M., Chinn, D. S., Torrence, M. H., Williamson, R. G., Cox, C. M., Rachlin, K. E., Wang, Y. M., Kenyon, S. C., Salman, R., Trimmer, R., Rapp, R. H., and Nerem, R. S., 1996, The development of the NASA GSFC and NIMA joint geopotential model. In: J. Segawa, H. Fujimoto, and S. Okubo (eds), Gravity, Geoid and Marine Geodesy, International Association of Geodesy Symposia, Vol. 117, Springer Berlin Heidelberg pp 461-469.
Lemoine, F. G., Smith, D. E., Kunz, L., Smith, R., Pavlis, E. C., Pavlis, N. K., Klosko, S. M., Chinn, D. S., Torrence, M. H., Williamson, R. G., Cox, C. M., Rachlin, K. E., Wang, Y. M., Kenyon, S. C., Salman, R., Trimmer, R., Rapp, R. H., and Nerem, R. S., 1998, The development of the NASA GSFC and NIMA joint geopotential model. NASA, technical report No. 206861.
Moon, P., Spencer, D. E., 1961, Field theory handbook. Springer-verlag, New york, Heidelberg, Berlin.
Pavlis, N. P., Chinn, D. S., Cox, C. M., Lemoine, F. G. 2000, Geopotential model improvement using POCM-4B Dynamic Ocean Topography Information: PGM2000A. Presented to Joint TOPEX/Poseidon and Iason-1 SWT Meeting Miami, FL. Nov. 15-17, 2000.
Pick, M., Picha, J., Vyskocil, V., 1973, Theory of the Earth’s Gravity Field. Elsevier Scientific Publishing Company.
Rapp, R. H., Wang, Y. M., Pavlis, N. K., 1991, The Ohio state 1991 geopotential and sea surface topography harmonic coefficient models. report No. 410, department of geodetic science and surveying, The Ohio State University, Columbus, Ohio.
Reigber, C., Schmidt, R., Flechtner, F., Konig, R., Meyer, U., Neumayer, K., Schwintzer, P., Zhu, S. Y., 2005, An earth gravity field model complete to degree and order 150 from GRACE:EIGEN-GRACE02S. J. Geophys. 39, 1-10.
Reigber, C., Schwintzer, P., Stubenvoll, R., Schmidt, R., Flechtner, F., Meyer, U., R., König(1), Neumayer, H., Förste, C., Barthelmes, F., Zhu, S. Y., Balmino, G., Biancale, R., Lemoine, J.-M., Meixner, H., Raimondo, J. C., 2004, A high resolution global gravity field model combining CHAMP and GRACE satellite mission and surface gravity data: EIGEN-CG01C. Accepted for publication in J. Geodesy.
Safari, A., 2004, Ellipsoidal boundary value problem for geoid computations via modulus of gravity, astronomical longitude, astronomical latitude, and satellite altimetry observations. Ph.D. thesis. Department of Surveying and Geomatics Engineering University of  Tehran (In Persian).
Safari, A., Ardalan, A. A., Grafarend, E. W., 2005, A new ellipsoidal gravimetric, satellite altimetry, astronomic boundary value problem; case study: geoid of Iran. J. Geodyn. 39, 545-568.
Sanso, F., 1979, The gravity space approach to the geodetic boundary value problem including rotational effects. Manuscr Geod., 4, 207-244.
Thong, N. C., and Grafarend, E. W., 1989, An ellipsoidal model of the terrestrial gravitational field. Manuscr Geodaet., 14, 285-304.
Tscherning, C. C., Rapp, R. H., and Goad, C., 1983, A comparison of methods for computing gravimetric quantities from high degree spherical harmonic expansions. Manuscr. geodaet. 8, 249-272.
Wenzel, H. G., 1999, Global models of gravity field of high and ultra-high resolution. In Lecture Notes of IAG’s Geoid school, Milano, Italy.