The Indian gravimetric geoid model based on the Curtin University approach with Featherstone-Evans-Olliver modification of the Stokes kernel: IndGG-CUT2021

The IndGG-CUT2021 is the Indian Gravimetric Geoid model developed using the Curtin University of Technology (CUT) approach, namely Moritz’s analytical solution to Molodensky’s problem, where Molodensky’s G₁ term is approximated by terrain correction. The method primarily calculates the quasigeoid model, which was converted to the geoid model by applying the geoid-quasigeoid separation term calculated using the method by Flury and Rummel (2009). Data used are terrestrial gravity anomalies from GETECH, satellite-altimeter derived marine gravity anomalies, MERIT digital elevation model, EIGEN6C4 and EGM2008 global geopotential models. The Featherstone-Evans-Olliver modified Stokes kernel was used in the calculations with various combinations of modification degree and integration radius. This gravimetric geoid model was obtained with the modification degree of 300 and an integration radius of 1°. The IndGG-CUT2021 model extends from 7° N to 37° N latitude and 68° E to 98° E longitude with a grid spacing of 0.02°×0.02° and it is referred to the GRS80 ellipsoid. On validation with the available GNSS/levelling data, mean±STD (in m) for India is -0.15±0.41. However, on cluster-wise validation in the four regions of the country, Uttar Pradesh West, Uttar Pradesh East, Hyderabad, and Bangalore, mean±STD (in m) are -0.57±0.12, -0.48±0.09, 0.11±0.16, and 0.77±0.03, respectively. The geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage.IndGG-CUT2021是印度重力大地水准面模型，采用科廷大学（Curtin University of Technology, CUT）方法构建，即莫里茨（Moritz）针对莫洛坚斯基（Molodensky）问题的解析解，其中莫洛坚斯基的G₁项通过地形改正进行近似。该方法首先计算似大地水准面模型（quasigeoid model），随后通过引入由弗吕里（Flury）与吕默尔（Rummel，2009）提出的方法计算得到的大地水准面-似大地水准面差值项，将似大地水准面模型转换为大地水准面模型。所用数据包括来自GETECH的陆地重力异常、卫星测高反演的海洋重力异常、MERIT数字高程模型（digital elevation model）、EIGEN6C4与EGM2008全球重力位模型。计算过程中采用了费瑟斯通-埃文斯-奥利弗改进型斯托克斯核（Featherstone-Evans-Olliver modified Stokes kernel），并对改进阶数与积分半径进行了多种组合测试。该重力大地水准面模型采用300的改进阶数与1°的积分半径生成。IndGG-CUT2021模型的覆盖范围为北纬7°至37°、东经68°至98°，网格分辨率为0.02°×0.02°，采用GRS80椭球面（GRS80 ellipsoid）作为参考椭球。利用现有GNSS/水准（GNSS/levelling）数据进行验证时，全印度范围内的平均偏差±标准差（standard deviation, STD，单位：米）为-0.15±0.41。但针对印度国内四个区域——西北方邦、东北方邦、海得拉巴以及班加罗尔——进行分区域验证时，对应的平均偏差±标准差（单位：米）分别为-0.57±0.12、-0.48±0.09、0.11±0.16与0.77±0.03。该大地水准面模型以ISG 2.0格式（ISG Format Specifications）提供，原始数据格式的文件可在该模型的ISG官方网页获取。

搜集汇总

背景与挑战

背景概述

IndGG-CUT2021是基于Curtin University方法开发的印度重力大地水准面模型，采用Featherstone-Evans-Olliver修正的Stokes核函数，整合了陆地重力、海洋卫星测高数据、数字高程模型和全球位模型等多源数据。模型覆盖印度地区（7°N-37°N, 68°E-98°E），网格精度为0.02°×0.02°，参考GRS80椭球体，整体验证精度达-0.15±0.41米，但区域精度存在差异。