Validating global hydrological models by ground and space gravimetry

作     者：ZHOU JiangCun1,2,3, SUN HePing1,2 & XU JianQiao1,2 1 Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China 2 Key Laboratory of dynamic geodesy, Chinese Academy of Sciences, Wuhan 430077, China 3 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 

作者机构：Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China Key Laboratory of dynamic geodesy Chinese Academy of Sciences Wuhan China Graduate University of Chinese Academy of Sciences Beijing China 

出 版 物：《Chinese Science Bulletin》 (CHINESE SCIENCE BULLETIN)

年 卷 期：2009年第54卷第9期

页      面：1534-1542页

核心收录：

学科分类：08[工学] 081501[工学-水文学及水资源] 0815[工学-水利工程] 

基　　金：Supported by Knowledge Innovation of Chinese Academy of Sciences (Grant No. KZCX2-YW-133) National Natural Science Foundation of China (Grant Nos. 40730316 and 40574034) Frontier Domain Item of Chinese Academy of Sciences 

主　　题：重力测量 水文模型 模型验证 和空间 地面 重力变化 季节性波动 空气压力 

摘      要：The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth s tides and variations in the Earth s rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2 in magnitude, and about 10×10-9 m s-2 for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2 induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.