文章基本信息

标题：Quantifying Topographic and Vegetation Effects on the Transfer of Energy and Mass to the Critical Zone
本地全文：下载
作者：Craig Rasmussen ; Jon D. Pelletier ; Peter A. Troch 等
期刊名称：Vadose Zone Journal
电子版ISSN：1539-1663
出版年度：2015
卷号：14
期号：11
页码：1-15
DOI：10.2136/vzj2014.07.0102
出版社：Soil Science Society of America, Inc.
摘要：Critical zone evolution, structure, and function are driven by energy and mass fluxes into and through the terrestrial subsurface. We have developed an approach to quantifying the effective energy and mass transfer (EEMT, MJ m −2 yr −1 ) to the subsurface that accounts for local variations in topography, water and energy balances, and primary production. Our objectives were to quantify how (i) local topography controls coupled energy and water transfer to the subsurface, and (ii) vegetation effects on local-scale evapotranspiration and primary production controls of energy and mass transfer to the critical zone, both at the pedon- to hillslope-scale resolution, in the context of quantifying controls on EEMT. The model was tested across a semiarid environmental gradient in southern Arizona, spanning desert scrub to mixed conifer ecosystems. Data indicated clear variations in EEMT by topography, via both aspect and local water redistribution, and with current vegetative cover. Key findings include: (i) greater values of EEMT on north-facing slopes in a given elevation zone, with a north-facing aspect equivalent to an ∼300-m elevation gain; (ii) a power law relationship between aboveground biomass and EEMT, with disturbance in the form of stand-replacing wildfire substantially reducing estimates of EEMT; and (iii) improved correlation of EEMT to pedon-scale variations in critical zone structure with EEMT values that include topography. Incorporating greater levels of environmental variation and complexity presents an improved approach to estimating the transfer of energy and mass to the subsurface, which is important to our understanding of critical zone structure and function.
关键词：AET; actual evapotranspiration; CZ; critical zone; DEM; digital elevation model; EEMT; effective energy and mass transfer; LAI; leaf area index; MCWI; mass conservative wetness index; NAIP; National Agriculture Imagery Program; NPP; net primary production; PET; potential evapotranspiration; PPT; precipitation; SCM; Santa Catalina Mountains.