High-resolution global atmospheric moisture connections from evaporation to precipitation

Abstract. A key Earth system process is the circulation of evaporated

moisture through the atmosphere. Spatial connections between evaporation and

precipitation affect the global and regional climates by redistributing

water and latent heat. Through this atmospheric moisture recycling,

land cover changes influence regional precipitation patterns, with

potentially far-reaching effects on human livelihoods and biome

distributions across the globe. However, a globally complete dataset of

atmospheric moisture flows from evaporation to precipitation has been

lacking so far. Here we present a dataset of global atmospheric moisture

recycling on both 0.5∘ and 1.0∘ spatial resolution. We

simulated the moisture flows between each pair of cells across all land and

oceans for 2008–2017 and present their monthly climatological means. We

applied the Lagrangian moisture tracking model UTrack, which is forced with

ERA5 reanalysis data on 25 atmospheric layers and hourly wind speeds and

directions. Due to the global coverage of the simulations, a complete

picture of both the upwind source areas of precipitation and downwind target

areas of evaporation can be obtained. We show a number of statistics of

global atmospheric moisture flows: land recycling, basin recycling, mean

latitudinal and longitudinal flows, absolute latitudinal and longitudinal

flows, and basin recycling for the 26 largest river basins. We find that, on

average, 70 % of global land evaporation rains down over land, varying

between 62 % and 74 % across the year; 51 % of global land

precipitation has evaporated from land, varying between 36 % and 57 %

across the year. The highest basin recycling occurs in the Amazon and Congo

basins, with evaporation and precipitation recycling of 63 % and 36 %

for the Amazon basin and 60 % and 47 % for the Congo basin. These

statistics are examples of the potential usage of the dataset, which allows

users to identify and quantify the moisture flows from and to any area on

Earth, from local to global scales. The dataset is available at https://doi.org/10.1594/PANGAEA.912710 (Tuinenburg et

al., 2020).