按克林索求和计算大地水准面差距垂线偏差及重力异常

本文采用克林索求和的方法,应用三个重力模型计算了东经80°~120°和北纬20°~40°之间的大地水准面差距、垂线偏差和重力异常。各模型截取到22阶次为止,并且将各模型计算的5°×5°大地水准面差距和垂线偏差平均值进行了比较。另外还对模型计算的平均重力异常与实测的平均重力异常进行了比较。

The Computation of Geoidal Undulation Deflection of Vertical and Gravity Anomalies Using Clenshaw Summation

In the pysical geodesy,spherical harmonic series are frequently used to compute geoidal undulation,deflection of vertical and gravity anomalies.However if the Clen-shaw summation were used,the computation could be made more convenient. Some comparisons have been made between the initially developed models A and B in our country and Rapp model,by 5°×5°mean geoidal undulation and deflection of vertical,covering an area of 80°-120°east longitude and 20°-40°north latitude.Each model has been truncated up to 22 degree and order.The comparison of mean gravity anomalies has been made between observational and each one of three models. The results show that:(1)ΔN_A,the difference of geoidal undulations between A model and Rapp model,has a systematic tilt near east-west direction.ΔN_B,the dif-ference between B model and Rapp model,has a strong ascent in North-West China and a descend in North-West China.(2)Δξ_B,the difference of components ξ,between B model and Rapp model,has a descend in Central China,and Δη_A,the differnce of components η,between A model and Rapp model,has a systematic tilt.(3)The mean errors of the differences of mean gravity anomalies obtained by obsevations and each one of three models separately are similar. The conclusion is that A and B models are not more suitable than Rapp model for our country.