Fig.1

Precipitation division map of Southwest China"

Table 1

Persistent extreme precipitation events in Western Sichuan from 1981-2016"

Fig.2

Composited wavelet power spectrum of persistent extreme precipitation events in Western Sichuan from 1981-2016"

Fig.3

Variations of time series of daily and accumulated precipitation on 15-30 d from May to September in 1998 (a) and synthetic precipitation and 15-30 d precipitation from 1981-2016 (b) in Western Sichuan"

Fig.4

Wind fields on 15-30 d (a) and wind field before filtering (b) at 700 hPa during the persistent extreme precipitation period from 1981-2016 in Western Sichuan"

Fig.5

Geopotential anomaly fields on 15-30 d (a) and geopotential fields before filtering (b) at 500 hPa during the persistent extreme precipitation period from 1981-2016 in Western Sichuan"

Fig.6

Vertical latitude cross-section of composited wind field (a) and vertical time cross-section of composited vorticity (b) on 15-30 d during the period of persistent extreme precipitation events from 1981-2016 in Western Sichuan"

Fig.7

Latitude-time cross-section zonal wind (a) and meridional wind (b) on 15-30 d along 85°-102°E at 700 hPa from 30 d before precipitation to 15 d after precipitation from 1981-2016 in Western Sichuan"

Fig.8

Evolution of low-frequency wind field on 15-30 d from the 2nd day (a) and 0 d (b) after the onset of precipitation and the 2nd day (c), 4th day (d), 6th day (e), and 8th day (f) before the onset of precipitation at 700 hPa from 1981-2016 in Western Sichuan"

Fig.9

Latitude-time cross-section of 15-30 d geopotential height anomaly and zonal wind (a) and meridional wind (b) along 90°-120°E at 500 hPa from 30 days before precipitation to 15 days after precipitation from 1981-2016 in Western Sichuan"

Fig.10

Evolution of geopotential height anomaly on 15-30 d synthesized from the 0 day (a) after the precipitation and the 5th day (b), 10th day (c), and 14th day (d) before the precipitation at 500 hPa from 1981-2016 in Western Sichuan"

Fig.11

Evolution of divergence and wind field on 15-30 d at 200 hPa from the 0 day (a) after the precipitation and the 5th day (b), 10th day (c), and 16th day (d) before the precipitation from 1981-2016 in Western Sichuan"