Validation of Circumpolar Albedo of Northern Lands from Landsat-8 and Sentinel-2
Angela Erb, University of Massachusetts Boston, angela.erb@umb.edu (Presenter)
Crystal Schaaf, University of Massachusetts Boston, crystal.schaaf@umb.edu
Zhan Li, Canadian Forest Service, zhanli1986@gmail.com
Zhuosen Wang, NASA GSFC/University of Maryland, zhuosen.wang@nasa.gov
Ian Paynter, University of Massachusetts Boston, ian.paynter@umb.edu
Shuai Zhang, University of North Carolina Chapel Hill, zshuai@email.unc.edu
Associated with rapid climate warming are multiple biophysical feedback relationships with the potential to contribute both positively and negatively to the overall warming and cooling of these regions. As a key factor in these relationships, land albedo plays an important role in the surface energy budget as it represents the proportion of incoming solar radiation reflected directly back to space, and consequently, that which is available to drive photosynthesis and surface heating.
The NASA MODIS MCD43 product suite is an established standard for daily global albedo products at 500m resolution since 2000 and has now achieved stage 4 validation through participation in the CEOS SALVAL effort. Suomi-NPP VIIRS (2011) provides continuity and continuation of the satellite record and global daily albedo products at 500 and 1000m resolutions (VNP43). The MCD43 and VNP43 products rely on the semi-empirical linear RossThick-LiSparse Reciprocal (RTLSR) Bidirectional reflectance distribution function (BRDF) model to characterize surface anisotropy, using a 16-day moving window to accumulate multi-angle observations for each pixel. Black sky (directional component) and white sky (diffuse component) albedos are calculated using the retrieved BRDF.
The long-term record of 30m Landsat observations and the more recently launched 20m Sentinel-2 sensors provide a higher resolution record of changes on the Earth’s surface. The Harmonized Landsat Sentinel (HLS) surface reflectance product combines data from these two platforms to provide continuity and consistency across both sensors. However, since Landsat and Sentinel-2 are near-nadir instruments, they do not provide the multi-directional observations necessary to reconstruct truly hemispherical surface albedo quantities. To generate a higher resolution albedo from these sensors, simultaneous surface anisotropy information from the daily MODIS BRDF products is used in conjunction with surface reflectance data to produce diffuse white-sky albedo (bihemispherical reflectance) and direct black-sky albedo (directional hemispherical reflectance).
Here we present a comprehensive evaluation of this broad suite of satellite albedo products across a broad spatial and temporal range following the CEOS surface albedo validation best practices protocol.
Associated Project(s):
Poster Location ID: 1-3
Presentation Type: Poster
Session: Poster Session 1
Session Date: Tue (May 9) 5:00-7:00 PM
CCE Program: LCLUC