中亚5月土壤湿度异常对6月降水的影响OACSTPCD

Using RA5 monthly reanalysis data from the European Centre for Medium-Range Weather Forecasts and monthly precipitation records from the Global Precipitation Climatology Centre spanning 1980 to 2019,this study examines the influence of May soil moisture anomalies on subsequent June precipitation variability in Cen-tral Asia.The findings unveil the following key insights:(1)The spatial distribution of springtime soil moisture exhibited elevated levels in Central Asia's northern and central regions and lower levels in the southwest and southeast.Maximum standard deviations occurred in southwest Central Asia during March and April.In the north of Central Asia,soil moisture experiences a noteworthy increasing trend in March but displays a declining trend from April to May.Conversely,southwest Central Asia witnessed substantial decreases in March.(2)June precipi-tation in Central Asia positively correlates with local soil moisture in May.Persistent wet soil moisture anomalies from May to June contribute to increased atmospheric precipitable water,modifying regional evaporation patterns in June.Heightened evaporation leads to increased latent heat flux and reduced sensible heat flux.A small Bowen ratio indicates a relatively shallow boundary layer that promotes low-layer moist entropy and a heightened poten-tial for convective activity.Consequently,June rainfall over the central regions of Central Asia increased.(3)A notable positive correlation exists between soil moisture in May and precipitation in June over middle Central Asia and the preceding winter Niño3.4 index.The influence of the preceding El Nino-Southern Oscillation(EN-SO)on June precipitation in middle Central Asia is mediated by May soil moisture.Nonetheless,soil moisture anomalies can independently impact the variability of June precipitation,separate from the influence of ENSO.