Sources of moisture for different intensities of summer rainfall over the Chinese Loess Plateau during 1979–2009

Abstract

ABSTRACTIn this study, moisture sources for different intensities of summer (June–July–August) rainfall over the Chinese Loess Plateau (CLP) were investigated by performing a transient simulation for the period 1979–2009 using the Lagrangian particle dispersion model FLEXPART. The results showed that continental areas surrounding the CLP, namely northwestern China–eastern central Asia and central eastern China, were major moisture source regions for summer rainfall over the CLP and that oceanic moisture originated from the East China Sea, the South China Sea, the Bay of Bengal, and the Arabian Sea played a secondary role. The moisture contribution of northwestern China–eastern central Asia to the CLP significantly decreased with increasing intensity of rainfall, whereas the contribution of central eastern China to the CLP slightly increased. Moreover, the moisture contribution of oceanic source regions to the CLP increased with the increased rainfall intensity. The East China Sea and the Bay of Bengal were the two most substantial oceanic moisture source regions for the 0–5th percentile (0–P5th) to 50th–75th percentile (P50th–P75th) rainfall classes, whereas the South China Sea and the Bay of Bengal were the two most substantial oceanic moisture source regions for the 75th–95th percentile (P75th–P95th) and the 95th–100th percentile (P95th–P100th) rainfall classes.