Atmospheric residence times from transpiration and evaporation to precipitation: An age‐weighted regional evaporation tagging approach

Abstract

The atmospheric water residence time is a fundamental descriptor that provides information on the timescales of evaporation and precipitation. In this study, a regional climate model-based evaporation tagging algorithm is extended with an age tracer approach to calculate moisture residence times, defined as time between the original evaporation and the returning of water masses to the land surface as precipitation. Our case study addresses how long this time is for the transpired and for the direct evaporated moisture. Our study region is the Poyang Lake region in Southeast China, the largest freshwater lake in the country. We perform simulations covering the period from October 2004 to December 2005. In 2005, 11% of direct evaporated water (10% of transpired water) precipitates locally. Direct evaporated water accounts for 64% and transpired water for 36% of the total tagged moisture with a mean age of around 36 h for both. Considering precipitation, a large proportion (69%) originates from direct evaporated water with a mean atmospheric residence time of 6.6 h and a smaller amount from transpired water with a longer residence time of 10.7 h. Modulated by the East Asian monsoon, the variation of the meteorological conditions, the magnitude of the partitioned moisture, and the corresponding residence time patterns change seasonally and spatially and reveal the different fate of transpired and direct evaporated water in the atmospheric hydrological cycle. We conclude that our methodological approach has the potential to be used for addressing how timescales of the hydrological cycle changes regionally under global warming.

A Joint Soil‐Vegetation‐Atmospheric Water Tagging Procedure With WRF‐Hydro: Implementation and Application to the Case of Precipitation Partitioning in the Upper Danube River Basin

“…The atmospheric branch of the hydrological cycle simulated by a climate model can be examined with a surface evaporation tagging method, which consists in tracking the evaporated water online, that is throughout the model run, from a source region until it precipitates or is advected outside of the simulation domain (Arnault, Knoche, et al, 2016;Dominguez et al, 2016;Insua-Costa & Miguez-Macho, 2018;Knoche & Kunstmann, 2013;Sodemann et al, 2009;Wei et al, 2015Wei et al, , 2016. It is noted that Arnault, Knoche, et al (2016) and Dominguez et al (2016) and Insua-Costa and Miguez-Macho's (2018) tagging methods were independently developed in the WRF model.…”

Land Surface Processes Create Patterns in Atmospheric Residence Time of Water

“…The global average time a water molecule spends in the atmosphere is 8-10 days (e.g., Bodnar et al, 2013;Bosilovich & Schubert, 2002;Chow et al, 1988;Jones, 1997;Trenberth, 1998;Van der Ent & Tuinenburg, 2017;Ward & Robinson, 2000;Yoshimura et al, 2004). Only recently, the regional differences in atmospheric residence times have been reported (Läderach & Sodemann, 2016;Van der Ent et al, 2014;Van der Ent & Tuinenburg, 2017;Wei et al, 2016). Van der Ent and Tuinenburg (2017) defined evaporation residence times at location x as the time a water particle at location x will spend in the atmosphere from the moment it evaporates until it returns to the Earth surface as precipitation at any location.…”

Interdecadal Variability of Summer Precipitation Efficiency in East Asia

“…Many studies have estimated PE as the precipitation amount divided by the mass of associated moisture sources, but the definition may vary with the specific context of water budget estimation. For example, PE can be defined as the ratio of precipitation rate to the sum of the surface evaporation and water vapor convergence from the perspective of large-scale water vapor budgets [28][29][30]. It can also be defined as the ratio of precipitation rate to the vertical integral of condensation and deposition rates derived from the cloud microphysical budget [9,31,32].…”

“…As PE is the reciprocal of atmospheric water residence time, its variability is closely associated with the activity of the East Asia summer monsoon (EASM) [19,21]. Wei et al [29] suggested that different age patterns of tagged precipitation in Southeast China reflect the varying impact of the EASM through prevailing wind directions and wind speeds.…”