An empirical formula relating the geomagnetic storm's intensity to the interplanetary parameters: -(VBz)over-bar and Delta t

作者：Wang YM^*; Shen CL; Wang S; Ye PZ

来源：Geophysical Research Letters, 2003, 30(20): 2039.

DOI：10.1029/2003GL017901

[1] We statistically study 105 geomagnetic storms with a Dst peak value less than or equal to -50 nT during 1998 - 2001 to examine the influence of the interplanetary parameters -(VB) over bar (z) and its duration Deltat on the intensity of geomagnetic storms. About 33% of the events are associated with intense storms with Dst(min) less than or equal to -100 nT. It is found that -(VB) over bar (z) is much more important than Deltat for the formation of geomagnetic storms. A stronger -(VB) over bar (z) can produce a more intense storm, whereas a longer Deltat can not. A simple empirical formula relating the Dst peak value to -(VB) over bar (z) and Deltat is obtained, which shows a good correlation ( CC = 0.9528) between the estimate value and the observations. This formula suggests that a compressed B-s field tends to have a more prominent geoeffectiveness. Moreover, we also identify 33 large -(VB) over bar (z) intervals with -(VB) over bar (z) > 5 mV/m and Deltat > 3 hours in the same study interval, and find that they all caused intense storms (Dst(min) less than or equal to - 100 nT) and 8/9 of the great storms (Dst(min) less than or equal to - 200 nT) were due to interplanetary compressed structures.

• 出版日期2003-10-22
• 单位中国科学技术大学