IGGGRACE01S模型确定的海面地形和地转流

用IGGGRACE01S、EIGENGRACE02S和EGM96地球重力场模型的前80阶分别计算出全球大地水准面,再与多颗测高卫星资料得到的平均海面高模型KMS04差分,构制出3种海面地形,并计算出相应的地转流。与Williams绘制的全球主要海流结果相比,不难看出,重力场模型IGGGRACE01S、EIGENGRACE02S的结果能清晰地显示出大尺度海洋地转流,而EGM96模型结果在赤道地带不明显。上述结果不仅显示了GRACE地球重力场模型IGGGRACE01S和EIGENGRACE02S具有较高精度探测地转流的能力,而且也表明了它们的长波精度优于EGM96模型,从应用角度展示了GRACE结果的有效性。

SEA SURFACE TOPOGRAPHY AND GEOSTROPHIC CURRENTS DERIVED FROM IGGGRACE01S MODEL

Three kinds of sea surface topographies have been derived from the difference between the mean sea level height model KMS04 compiled from several altimeter satellite data and the geoids derived from IGGGRACE01S, EIGENGRACE02S and EGM96 gravity field models intercepted to the 80th respectively. The calculated sea surface topographies are used to derive geostrophic currents, and the results are compared with the main ocean circulations drawn by Williams. We have found that the large-scale geostrophic currents are clearly observed with IGGGRACE01S and EIGENGRACE02S solutions, but the EGM96 solution shows no strong currents in equatorial band. The results indicate that not only the GRACE gravity field model IGGGRACE01S and EIGENGRACE02S can detect geostrophic currents with high accuracy, but also the models are more accurate than EGM96 model in long-medium wave, the application validity of GRACE result is proved.