Global ocean surface geostrophic currents estimated from satellite altimetry,GRACE and GOCE
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摘要: 重力恢复和气候试验GRACE(gravity recovery and climate experiment)卫星极大地提高了地球重力场的精度和分辨率,特别是中长波分量,联合卫星测高数据可获得全球海洋表面大尺度洋流循环。另外,新一代地球重力和海洋环流探测卫星GOCE(gravity field and steady-state ocean circulation explorer)于2009年3月成功发射,采用卫星重力梯度测量原理,对重力场的高频部分非常敏感,使其高分辨率监测全球海洋循环成为可能。本文利用1~7年GRACE观测数据确定的重力场模型和18个月GOCE观测数据确定的地球重力场模型GO_CONS_GCF_2_TIM_R3,联合卫星测高确定的平均海面高模型MSS_CNES_CLS_11,分别估计全球海洋表面地转流,并且与实测浮标数据结果进行比较。分析表明GOCE重力卫星确定的重力场模型具有更高的空间分辨率,能够确定高精度和高空间分辨率的全球海洋地转流,如墨西哥湾暖流的细节和特征,并且与实测浮标结果基本一致。而基于1~4年GRACE观测资料的模型不能很好估计全球地转流特征,基于7年GRACE观测资料的重力场模型ITG-Grace2010s确定的全球地转流的精度仍低于18个月GOCE观测数据确定的地球重力场模型GO_CONS_GCF_2_TIM_R3的结果,估计的全球地转流仍含有较大的噪声,不能很好地反应中小尺度地转流细节特征。并计算ITG_Grace2010s和GOCE_TIM3的稳态海面地形和全球平均地转流的内符合精度,结果显示,在全球范围内,GOCE_TIM3的稳态海面地形和全球平均地转流的精度都比ITG_Grace2010s结果的精度有着很大的改善,其中ITG_Grace2010s的稳态海面地形的精度为21.6 cm,而GOCE_TIM3的结果则为7.45 cm,ITG_Grace2010s的全球平均地转流的精度为40.7 cm/s,而GOCE_TIM3的结果则为19.6 cm/s。Abstract: The satellite gravity mission GRACE (gravity recovery and climate experiment) has greatly improved the accuracy and resolution of the gravity field model of the earth,particularly in long-wave components. It can determine the characteristics of large scale global ocean surface currents combining satellite altimetry. In addition,the new generation GOCE (gravity field and steady-state ocean circulation explorer) mission was successfully launched in 2009 using gravity gradient measurements,which is very sensitive to the high-frequency part of the gravity field. Therefore,the GOCE is capable to determine the ocean surface currents with high spatial resolution. In this paper,the global surface geostrophic currents are determined from three models: (1)the gravity field model derived from 1 to 7 years of GRACE observations;(2)the gravity field model GO_CONS_GCF_2_TIM_R3 derived from one and half years of GOCE observations; (3) the mean sea surface topography model MSS_CNES_CLS_11 derived from satellite altimetry. It has shown that the gravity field model based on GOCE satellite gravity observations has a higher spatial resolution and can reflect more details and characteristics of the surface geostrophic currents with high accuracy and spatial resolution,e.g.,the medium and small-scale Mexico Gulf currents. Furthermore,the predictions are consistent with the in-situ drifters buoy data. However,the gravity model from 1 to 4 years of GRACE observations cannot predict global geostrophic currents accurately,and even the model from 7 years of GRACE observations is still less accurate than that from the one and half years of GOCE observations; the former one cannot reveal the details of current at the medium and small scales and has larger noises.
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Key words:
- geostrophic currents /
- GOCE /
- GRACE /
- satellite altimetry
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黄瑞新. 大洋环流:风生与热盐过程[M].乐肯堂,史久新,译.北京:高等教育出版社,2012. Tapley B D,Chambers D P,Bettadpur S,et al. Large scale ocean circulation from the GRACE GGM01 Geoid[J]. Geophys Res Lett,2003,30(22): 2163-2166. Maximenko N,Niiler P,Centurioni L,et al. Mean dynamic topography of the ocean derived from satellite and drifting buoy data using three different techniques[J]. J Atmos Oceanic Technol,2009,26(9): 1910-1919. Jin S G,Chambers D P,Tapley B D. Hydrological and oceanic effects on polar motion from GRACE and models[J]. J Geophys Res,2010,115: B02403. 张子占,陆洋,许厚泽. 利用卫星测量技术和小波滤波方法探测表层地转流[J]. 中国科学D辑: 地球科学,2007,37(6):753-760. Drinkwater M R,Floberghagen R,Haagmans R,et al. GOCE: ESA’s first Earth Explorer core mission[J]. Space Science Reviews,2003,108(1/2): 419-432. Mayer GÖrr,Eicker A,Kurtenbach E,et al. ITG-GRACE: global static and temporal gravity field models from GRACE data[M]//System Earth via Geodetic-Geophysical Space Techniques.Berlin:Springer,2010:159-168. Pail R,Bruinsma S,Migliaccio F,et al. First GOCE gravity field models derived by three different approaches[J]. J Geod,2011,85(11): 819-843. Heiskanen W A,Mori H.Physical Geodesy[M]. W H Freemand and Company,San Francisco and London,1967. Stewart R H. Introduction to Physical Oceanography[M]. California,San Diego: Texas A & M University,2008. Schaeffer P,Faugere Y,Legeais J F,et al. The CNES_CLS11 global mean sea surface computed from 16 years of satellite altimeter data[J]. Marine Geodesy,2012,35(supl): 3-19. Hughes C W,Bingham J R. An oceanographer’s guide to GOCE and the geoid[J]. Ocean Sci Discuss,2008,4: 15-29. Bingham R J,Haines K,Hughes C W. Calculating the ocean’s mean dynamic topography from a mean sea surface and a geoid[J]. J Atmos Ocean Technol,2008,25:1808-1822. Albertella A,Rummel R. On the spectral consistency of the altimetric ocean and geoid surface,a one-dimensional example[J]. J Geod,2009,83: 805-815. Jekeli C. Alternative methods to smooth the earth’s gravity field.Columbus:Ohio State University,1981. Wahr J,Molenaar M,Bryan F. Time-variability of the Earth’s gravity field: Hydrological and oceanic effects and their possible detection using GRACE[J]. J Geophys Res,1998,103:32,205-30,229. Knauss J A. Introduction to physical oceanography[M]. 2ed. New Jersey: Prentice-Hall,1997: 309-310, Lagerloef G S E,Mitchum G T,Lukas R B,et al. Tropical Pacific near-surface currents estimated from altimeter,wind,and drifter data[J]. J Geophys Res,1999,104(C10): 23313-23326. Lumpkin R,Garraffo Z. Evaluating the decomposition of tropical Atlantic drifter observations[J]. J Atmos Oceanic Technol,2005,22: 1403-1415. Lumpkin R,Pazos M. Measuring Surface currents with Surface Velocity Program Drifters: the Instrument,its Data,and some Recent Results[M]. Cambridge University Press,2007. Mann C R. The termination of the Gulf Stream and the beginning of the North Atlantic Current[J]. Deep Sea Research and Oceanographic Abstracts,1967,14(3): 337-359. Gould W J. Physical oceanography of the Azores front[J]. Prog Oceanog,1985,14: 167-190. Albertella A,Savcenko R,Janjic T,et al. High resolution dynamic ocean topography in the Southern Ocean from GOCE[J]. Geophys J Int,2012,190: 922-930.
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