Response of geomagnetic jerk features to the geomagnetic secular acceleration in the China region

Studying the relationship between geomagnetic jerks and the geomagnetic secular acceleration (SA) in the China region is helpful for better understanding the regional characteristics of geomagnetic jerks and provides useful information for investigating the geodynamic origin of geomagnetic jerks. In this study, the spatiotemporal response relationship between geomagnetic jerks and SA in the China region since 2000 is investigated, based on data collected at geomagnetic observatories in China and the CHAOS-7 geomagnetic field model. The results show that the characteristics of the geomagnetic SA differ between the eastern and western hemispheres. In the Western Hemisphere, SA patches often occur near the equator and tend to drift westward. While in the Eastern Hemisphere, SA patches move back and forth in the north-south and eastwest directions. Geomagnetic jerks are closely related to the intensity and location of SA patches, with geomagnetic jerks typically occurring during periods of minimum geomagnetic secular acceleration intensity (SAI). Since 2000, the global SAI reached its maximum around 2006, 2009, mid-2012 and 2016, and its minimum around 2003, 2007, 2011 and 2014. As we can see, in the China region, jerks occurred in 2003 and 2014, corresponding to not only the periods of minimum SAI in the Eastern Hemisphere, but also the transition periods of the polarity-reversal of positive and negative SA patches. However, no jerks were detected in the China region in 2007 and 2011, mainly due to a lack of polarity-reversal of SA patches in the China region around these two years. Additionally, the SA pulses patches in the Eastern Hemisphere were mainly distributed in the Southern Hemisphere and thus far away from the China region. These pulse patches mainly caused small fluctuations in the geomagnetic secular variation in the China region.