Project Funding: 2011 - 2014

NRA: 2009 NASA: The Science of Terra and Aqua   

Funded by NASA

Abstract:
Numerous papers have highlighted how land-cover change and ecosystem disturbance can alter the surface energy balance through changes in albedo, surface roughness, and evapotranspiration. In some cases, these surface changes may constitute a larger radiative forcing than those arising from related carbon emissions. Past studies on post-disturbance albedo have been limited by the resolution of available MODIS data (500m), which is significantly coarser than the characteristic scales of ecosystem disturbance and human land use. Our project addresses this issue by creating high-resolution (30m) albedo maps through the fusion of Landsat TM/ETM+ directional reflectance with MODIS BRDF/Albedo (MCD43A) data. These maps permit trends in albedo to be evaluated at the characteristic scale of vegetation change (~1 ha). Two algorithms are proposed to retrieve Landsat-resolution albedo: a "concurrent approach" which depends on overlapping MODIS and Landsat observations from the 2000-2010 period, and an "extended approach", which uses an a priori BRDF table to extend retrievals back to the 1980's. These fused products will be validated using in-situ Baseline Surface Radiation Network (BSRN) data. We will then evaluate the albedo trajectories for characteristic types of land cover conversion and disturbance across the globe. Specifically, we will (i) assemble a regional library of albedo values for IGBP land cover types; (ii) assemble time series of post-disturbance albedo from a latitudinal distribution of typical forest disturbance types (fire, insect damage, harvest); (iii) evaluate decadal trends in landscape albedo for "hotspots" of vegetation change; and (iv) assess the radiative forcing associated with historical (since 1700) and future (scenario-based) global land-cover change. The outcome of the investigation will be an improved quantification of recent and historical albedo changes associated with land cover change and forest disturbance. Such information is needed to reduce uncertainties present in the current IPCC WG1 radiative forcing budget, and to forecast the effects of land management and land cover conversion on future climate.

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Albedo Response to Land Use Change and Disturbance: A Multi-sensor Approach   --   (Jeffrey Masek, Feng Gao, Christopher A Williams, Crystal Schaaf, Yanmin Shuai, Bardan Ghimire)   [abstract]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Albedo Response to Disturbance from Integrating Landsat and MODIS Data   --   (Jeffrey Masek, Yanmin Shuai, Feng Gao, Crystal Schaaf, Christopher A Williams, Zhuosen Wang)   [abstract]   [poster]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile