An Overview of the Use of the SimSphere Soil Vegetation Atmosphere Transfer (SVAT) Model for the Study of Land-Atmosphere Interactions

George Petropoulos,Martin J Wooster,Toby N Carlson

doi:10.3390/s90604286

Abstract

Soil Vegetation Atmosphere Transfer (SVAT) models consist of deterministic mathematical representations of the physical processes involved between the land surface and the atmosphere and of their interactions, at time-steps acceptable for the study of land surface processes. The present article provides a comprehensive and systematic review of one such SVAT model suitable for use in mesoscale or boundary layer studies, originally developed by [1]. This model, which has evolved significantly both architecturally and functionally since its foundation, has been widely applied in over thirty interdisciplinary science investigations, and it is currently used as a learning resource for students in a number of educational institutes globally. The present review is also regarded as very timely, since a variation of a method using this specific SVAT model along with satellite observations is currently being considered in a scheme being developed for the operational retrieval of soil surface moisture by the US National Polar-orbiting Operational Environmental Satellite System (NPOESS), in a series of satellites that are due to be launched from 2016 onwards.

Highlights

As reported by [5], the degree of realism of a Soil Vegetation Atmosphere Transfer (SVAT) model generally depends on the models structural complexity, the representativeness and configuration of the different components, the quality of the input data used for parameterisation, and on the site-specific conditions such as local climate, biophysical and geophysical characteristics and their ability to be represented by the parameterisations contained within the model
For convenience and efficiency, we propose a categorisation of the SVAT models use into the following three main groups, based on the focus of the study in question: 1) Evaluation of the land surface parameters simulated by the SVAT model, including sensitivity analysis studies
The present article has provided, for the first time, a comprehensive and systematic overview of the use of the 1D SVAT model originally developed by [1], with the most recent implementation of this model being termed “SimSphere”. This overview complements the study of [15] which focused primarily on the description and relative advantages and disadvantages of the “triangle” method by which this SVAT model can be linked to remote sensing data obtained from satellite or airborne instruments

Summary

Introduction

Surface-Vegetation-Atmospheric Transfer (SVAT) models are mathematical representations of vertical ‘views’ of the physical mechanisms controlling energy and mass transfers in the soil/vegetation/atmosphere continuum, providing deterministic estimates of the time course of soil and vegetation state variables at time-steps compatible with the dynamics of atmospheric processes [2]. An overview of the use of this SVAT model, which here for clarity we refer to as the “SimSphere” model by the name of its most recent implementation, both as a standalone application and via its coupling to remotely sensing data in the “triangle” method and elsewhere, is at present somewhat lacking from the literature This despite the extensive use of this specific SVAT model by the scientific community in a large number of interdisciplinary science studies [16,17,18,19], and its exploitation as an educational resource in a number of Universities worldwide The article complements as well the study of [15], which focused solely on the principles and limitations of the “triangle” method alone

Overview of the SVAT Model Architecture

Overview of SVAT Model Use

Discussion and Conclusions