Sub-Monthly Co-Occurrence of Low Precipitation and Low Wind-Power Density in Southwest China, 1979–2018

This study quantifies same-grid-cell, same-date co-occurrence of low precipitation and low operational wind-power density (WPD) in Southwest China during 1979–2018. Daily precipitation and WRF-derived 10 m wind fields were analyzed on a 271 × 271 grid with 10-, 15-, 20-, and 30-day rolling windows. At each grid cell, rolling precipitation totals and rolling means of the daily operational-WPD index were ranked against a fixed seasonal distribution. Low conditions were defined by u≤0.1587, with sensitivity analyses at u≤0.10 and u≤0.20. Low precipitation represented a sub-monthly meteorological-drought condition. Domain compound frequency declined from 2.207% at 10 days to 1.704% at 30 days. Warm-season frequency was highest at every window, ranging from 2.624% to 2.028%. R3 had the highest compound frequency at the central threshold, whereas R5 had the lowest. Under the 1% regional active-area rule, median compound runs lasted three to five days. Spatial-block intervals changed with block size, so the 40-year record does not support a robust domain-wide trend conclusion. The results provide a 1979–2018 climatology of atmospheric precipitation–WPD co-occurrence.