Moisture Transport and Contribution to the Continental Precipitation

Abstract

Understanding the water cycle change under a warming climate is essential, particularly the ocean to land moisture transport, which affects the precipitation over land areas and influences society and the ecosystem. Using ERA5 data from 1988 to 2020, the time series of moisture transport and the trend across the boundary of each continent, including Eurasia, Africa, North America, South America, Antarctic, Australia, and Greenland, have been investigated. The inflow and outflow sections of the moisture have been identified for each continent. The trends of moisture convergence over Eurasia, Africa, North America, and Antarctic are all positive, with the values of 2.59 ± 3.12, 2.60 ± 3.17, 12.98 ± 2.28, and 0.32 ± 0.47 (in 106 kg/s/decade), respectively, but only the trend over North America is statistically significant at a 0.1 significance level. The moisture convergence trend of −0.59 ± 3.63 (in 106 kg/s/decade) over South America is negative but insignificant. The positive trend of 0.10 ± 0.35 (in 106 kg/s/decade) over Greenland is very weak. The precipitation, evaporation, and moisture convergence are well balanced at middle and low latitudes, but the combination of moisture convergence and evaporation is systematically lower than the precipitation over Antarctic and Greenland. Contributions of evaporation and moisture convergence (or transport) to the continental precipitation vary with the continent, but the moisture convergence dominates the precipitation variability over all continents, and the significant correlation coefficients between the anomaly time series of continental mean moisture convergence and precipitation are higher than 0.8 in all continents.

Changes in atmospheric moisture transport over tropical South America: an analysis under a climate change scenario

“…Climate change induced by increasing GHG concentrations is expected to intensify but modify the regional characteristics of atmospheric moisture transport (Lavers et al 2015;Zhang et al 2021;Yang et al 2022). Therefore we analyzed the projected changes in the transport and recycling of atmospheric moisture contributing to PW and P over the three continental regions of interest in tropical South America by the late twenty-first century under the RCP8.5 scenario.…”