Based on the very high frequency (VHF) radar data during 2014.03–2019.02 from Fuke station, we presented a statistical analysis of the presunset bottom-type scattering layers (BSLs) on geomagnetic quiet days at low latitudes and preliminarily discussed the relationship between geomagnetic activities and presunset BSLs. It is found that when the seasonally mean F10.7 index is less than 120 during the descending phase of solar cycle (2015–2018), the occurrence rate (OR) of presunset BSLs in the same season also decreases year by year. Except for 2014, all the highest OR values in each year appear in the equinoctial months, but the equinoctial asymmetry is also obvious. Besides the peak values in equinoctial months (mainly March and September), there is also a crest of OR in May during 2015–2017. As for the temporal and altitudinal characteristics, the peak OR of presunset BSLs always appears during 10:45-11:00UT (18:03–18:18LT) and the height ranges from 190 km to 306 km. In addition, it seems that the geomagnetic disturbances might have certain positive impacts on the generation of low-latitude presunset BSLs.

基于福克站2014.03-2019.02甚高频雷达资料，对低纬度地磁平静日的日落前底型散射层（BSLs）进行了统计分析，初步探讨了地磁活动之间的关系和presunset BSL。研究发现，在太阳活动周期下降阶段（2015-2018）季节性平均F10.7指数小于120时，同季日落前BSL的发生率（OR）也逐年下降。除 2014 年外，每年的最高 OR 值均出现在春分月，但春分的不对称性也很明显。2015-2017 年间，除春分月（主要是 3 月和 9 月）出现峰值外，5 月也出现 OR 峰值。至于时空特征，日落前 BSL 的 OR 峰值始终出现在 10:45-11:00UT（18:03-18:18LT），高度范围为 190 km 至 306 km。此外，地磁扰动似乎可能对低纬度日落前BSL的产生产生一定的积极影响。