secular variation

The temporal variation of it has secular change, seasonal variation, irregular variation, and other scales variation.

重力场的时变有长期变化 、 季节性变化 、 不规则变化和其他多尺度的变化.

Analysis of the geomagnetic secular variation in eastern Asia during the last 30 years

近30年来东亚地区地磁长期变化分析

According to the observation data at Urumqi geomagnetic station since the historic times, we sum up and analyse the laws of the geomagnetic secular variation, geomagnetic short period variation and the activity of magnetic storm.

根据乌鲁木齐地磁台有史以来的地磁观测资料，对该地区地磁场的长期变，短期变及其磁暴活动规律进行了总结分析。

732 Chinese lunar records are used to study the secular variation of the earth's rotation. Ancient Astronomical Observation and Applied Historical Astronomy

地球自转长期变化的研究依赖于古代天象记录.近年来这方面研究取得明显进展.古代天象记录与应用历史天文学

Analysis on Secular Variation of Air Humidity and Precipitation in the Shihezi Oasis

石河子绿洲空气湿度和降水的长期变化趋势分析

The main geomagnetic field, B, and its secular variation,, originate from same dynamo process in the outer core.

地球主磁场B和它的长期变化.B都起源于地球外核的磁流体发电机过程，但是，它们的空间结构和时间演化特征却有很大差异。

Drift shell tracing method and the secular variation of inner radiation fluxes

漂移壳追踪方法与内辐射带的长期变化

The effects of the unusual behaviors in high-degree Gauss coefficients of IGRF 1945~ 1955 on the secular variation are studied by using the eighth generation of IGRF. By comparing the original and the revised IGRF models, the errors in the high-degree coefficients are estimated and corrected.

本文根据第八代IGRF模型，分析了IGRF1945～1955中高阶球谐系数的异常特征对长期变化的影响，然后用修正IGRF模型估计并改正了这些影响。

Study of secular variation of geomagnetic field by means of VGP

用虚地磁极（VGP）方法对地磁场随时间变化的研究