Spatial distribution and seasonal variation characteristics of global atmospheric moisture recycling

Abstract

This paper makes use of new definitions of moisture recycling to study the complete process of global moisture feedback. An accounting procedure based on ERA-Interim reanalysis data is used to calculate moisture recycling ratios. Furthermore, the spatial distribution and seasonal variation characteristics of global moisture recycling are analyzed. Results indicate that: a) Precipitation recycling ratio in different regions show distinct patterns. It is indicated that the dependences of precipitation in different regions on moisture transport are different. b) Spatial distribution of precipitation recycling ratio and evaporation recycling ratio are in good agreement over the lands, but show significant difference over the oceans. c) Seasonal variation characteristics of global moisture recycling ratio are significant, which are stronger in the Northern Hemisphere than in the Southern Hemisphere. d) Main oceanic sources are dominant over continental moisture recycling, and most of the evaporation is transported to other regions by advection. e) Regional moisture recycling ratio not only depends on the factors such as time, location, and shapes of the regions, but also the regional horizontal scale. The moisture recycling ratio curve rises as the regional horizontal scale increases. It is computed that, on the average, precipitation recycling ratio and evaporation recycling ratio of Chinese mainland are respectively about 32.6% and 44.9%; the main source of rainfall in China is moisture evaporated over the South China Sea, the Bay of Bengal, the Arabian Sea and the Western Australia Ocean. The atmospheric moisture recycling model in this paper is based on the atmospheric water balance equation, in terms of good mathematical and physical theory, hence the results are credible.