Vegetation‐hydrology dynamics in complex terrain of semiarid areas: 1. A mechanistic approach to modeling dynamic feedbacks

Abstract

[1] Vegetation, particularly its dynamics, is the often-ignored linchpin of the land-surface hydrology. This work emphasizes the coupled nature of vegetation-water-energy dynamics by considering linkages at timescales that vary from hourly to interannual. A series of two papers is presented. A dynamic ecohydrological model [tRIBS + VEGGIE] is described in this paper. It reproduces essential water and energy processes over the complex topography of a river basin and links them to the basic plant life regulatory processes. The framework focuses on ecohydrology of semiarid environments exhibiting abundant input of solar energy but limiting soil water that correspondingly affects vegetation structure and organization. The mechanisms through which water limitation influences plant dynamics are related to carbon assimilation via the control of photosynthesis and stomatal behavior, carbon allocation, stress-induced foliage loss, as well as recruitment and phenology patterns. This first introductory paper demonstrates model performance using observations for a site located in a semiarid environment of central New Mexico.

Describing the interannual variability of precipitation with the derived distribution approach: effects of record length and resolution

“…Under this derived distribution (DD) approach (Benjamin and Cornell, 1970, p. 100), only a few years of continuously gauged precipitation data, from which storm arrivals and depths can be extracted and their distributions estimated, are necessary to estimate the probability distribution of annual precipitation for a site. Even though Eagleson's (1978) original paper has a large number of citations, most of these relate to ecohydrological modeling of soil moisture and vegetation dynamics (e.g., Dufrêne et al, 2005;Ivanov et al, 2008), derived distributions of runoff and flood frequency (e.g., Freeze, 1980;Díaz-Granados et al, 1984), rainfall modeling (for example, Onof et al, 1998;Willems, 2001), or morphological evolution of drainage basins (Tucker and Bras, 2000). We are not aware of any previous attempt at applying Eagleson's DD approach to the study of the interannual variability of precipitation, even though the method seems particularly well suited to deal with locations with short records, as well as to account for nonstationarities introduced by a changing climate.…”

Physically based modeling of rainfall-triggered landslides: a case study in the Luquillo forest, Puerto Rico

“…Increasing the values of anisotropy ratio enhances the ability of the model in reproducing the rapid lateral moisture exchange. A similar approach and such high values of anisotropy have been used by Ivanov et al (2008b).…”

“…Consequently, when applied to a catchment, the model offers a quasi-three-dimensional framework by which lateral moisture transfers and difference in topographic characteristics may lead to the spatio-temporal variability of states (Ivanov et al, 2008b).…”

Application of a hillslope-scale soil moisture data assimilation system to military trafficability assessment

“…A full description of the tRIBS-VEGGIE model is outside the scope of this applied study. The reader is referred to [27][28][29][30] for a more extensive overview of the model physics and [8,18,26] for its application in the development of the data assimilation framework used in this study.…”

“…The simulation core of the hillslope-scale data assimilation system is a coupled biophysical and hydrologic system referred to as the Triangulated Irregular Network (TIN)-based Realtime Integrated Basin Simulator (tRIBS) [27,28] and VEGetation Integrated Evolution (VEGGIE) [29,30] models (collectively tRIBS-VEGGIE). The tRIBS-VEGGIE resolves mass, energy and carbon balance at hillslope scales (10s to 100s of m) within a watershed.…”