Contrasting roles of interception and transpiration in the hydrological cycle - Part 1: Temporal characteristics over land
2014 (English)In: Earth System Dynamics, ISSN 2190-4979, E-ISSN 2190-4987, Vol. 5, no 2, 441-469 p.Article in journal (Refereed) Published
Moisture recycling, the contribution of terrestrial evaporation to precipitation, has important implications for both water and land management. Although terrestrial evaporation consists of different fluxes (i.e. transpiration, vegetation interception, floor interception, soil moisture evaporation, and open-water evaporation), moisture recycling (terrestrial evaporation-precipitation feedback) studies have up to now only analysed their combined total. This paper constitutes the first of two companion papers that investigate the characteristics and roles of different evaporation fluxes for land-atmosphere interactions. Here, we investigate the temporal characteristics of partitioned evaporation on land and present STEAM (Simple Terrestrial Evaporation to Atmosphere Model) - a hydrological land-surface model developed to provide inputs to moisture tracking. STEAM estimates a mean global terrestrial evaporation of 73 900 km(3)year(-1), of which 59% is transpiration. Despite a relatively simple model structure, validation shows that STEAM produces realistic evaporative partitioning and hydrological fluxes that compare well with other global estimates over different locations, seasons, and land-use types. Using STEAM output, we show that the terrestrial residence timescale of transpiration (days to months) has larger inter-seasonal variation and is substantially longer than that of interception (hours). Most transpiration occurs several hours or days after a rain event, whereas interception is immediate. In agreement with previous research, our simulations suggest that the vegetation's ability to transpire by retaining and accessing soil moisture at greater depth is critical for sustained evaporation during the dry season. We conclude that the differences in temporal characteristics between evaporation fluxes are substantial and reasonably can cause differences in moisture recycling, which is investigated more in the companion paper (van der Ent et al., 2014, hereafter Part 2).
Place, publisher, year, edition, pages
2014. Vol. 5, no 2, 441-469 p.
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:su:diva-113142DOI: 10.5194/esd-5-441-2014ISI: 000346140900013OAI: oai:DiVA.org:su-113142DiVA: diva2:791337