Evaluating a simple proxy for climatic cloud‐to‐ground lightning in Sichuan Province with complex terrain, Southwest China

Lightning matters to human life and natural fires so much that monitoring and predicting lightning are highly important. A simple proxy for climatic cloud‐to‐ground (CG) density is evaluated defined as the product of convective available potential energy (CAPE) and precipitation rate using data from 2005 to 2017 in Sichuan of Southwest China. CAPE times precipitation rate (CP) relates the monthly distribution and magnitude of negative lightning in the basin region more closely, while CP describes the monthly distribution and magnitude of positive lightning in the plateau region more appropriately. Except for individual years, the annual variation trend and magnitude of CP and positive and negative lightning are relatively consistent in the basin region, while the description of the annual variation trend and magnitude of lightning by CP in the plateau region is insufficient, especially for negative lightning. CP represents the high‐value areas of the positive and negative lightning in the basin and southern Sichuan reasonably, but misses the lightning belt in the plateau region. In general, the performance of CP for lightning in the basin is superior to that in the plateau, this may be caused by two factors, one is the particularity and complexity of lightning in the plateau resulted from special topographic and meteorological conditions, the other one is the limitation of CP caused by the fact that CP does not take into account other environmental factors contributing to lightning. The ability of this simple proxy to describe CG lightning in Sichuan is limited by vertical wind shear in the middle and lower troposphere, zero degree height, and liquid water path, mainly because the proxy does not have the ability to generalize these factors that play a key role in lightning activity. In the Sichuan region, the scaling CP can reproduce the total CG lightning reasonably, with a determination coefficient of .64. In the basin region, the scaling CP and total CG lightning show the best correlation, with a determination coefficient of .68, which is better than that in the basin region, with a determination coefficient of .54. In general, although limited by the complexity of the terrain and meteorological conditions, CP is used as a proxy for lightning prediction in the Sichuan region, which could still reasonably represent the distribution characteristics of total CG lightning.