Comparison of land cover data products and their impact on continental water assessments

[摘要] The Australian Water Resources Assessment (AWRA) is an integrated continental modelling system for detailed water balance analysis at continental to sub-catchment scale that will form part of the Bureau of Meteorology’s Australian Water Resources Information System (AWRIS). Each grid cell in the model includes one or more Hydrological Response Units (HRUs) where water and energy fluxes are simulated separately (Van Dijk 2010). The current version of AWRA-L includes two HRUs: tall, deep rooted vegetation and short, shallow rooted vegetation. As these two HRUs use water differently, reliable estimates of these within each AWRA-L cell are required in order to accurately model water balance. There are a number of broad scale land cover products that could provide information on fractional cover. The current version of AWRA-L uses the AVHRR-based persistent and recurrent vegetation fractions described by Donohue et al. (2008) with the assumption that persistent and recurrent vegetation are proxies for tall, deep rooted and short, shallow rooted. An alternative data source is the forest, non-forest data produced from Landsat imagery as input to the National Carbon Accounting System (Furby, 2002). Each of these datasets has continental coverage and is regularly updated, thus providing a practical basis for estimates of AWRA-L HRU fractions. However, these two datasets show markedly different patterns across the landscape and their relationship to the true fractional cover of deep and shallow rooted vegetations is untested. Here we present the investigation of discrepancy and explains the sources of variation between these land cover products. A number of targeted studies were also conducted in order to explain the relationship between each product and detailed airborne Lidar-based assessments of vegetation structure. The impact of the use of each product on the ability of AWRA-L to simulate daily streamflow is also assessed at 186 catchments across Australia.References:Furby S. (2002) Land Cover Change: Specification for remote sensing analysis. National Carbon Accounting System Technical Report No.9. Australian Greenhouse Office.Donohue RJ, Roderick ML, McVicar TR(2008) Deriving consistent long-term vegetation information from AVHRR reflectance data using a cover-triangle-based framework. Remote Sensing of Environment, 112, 2938-2949.Van Dijk, AIJM. (2010). The Australian Water Resources Assessment System. Technical Report 3. Landscape Model (version 0.5) Technical Description. CSIRO: Water for a Healthy Country National Research Flagship

[发布日期] 2011-11-24 [发布机构] CSIRO

[学科分类] 地球科学(综合)