MODIS Albedo Subsets for Selected Field sites Bob Cook, Steve Margle, Susan Holladay, and Lisa Olsen Oak Ridge National Laboratory Oak Ridge, Tennessee, USA 2nd CEOS/WGCV/ Land Product Validation (LPV) Workshop on Albedo Products Vienna, Austria April 28–29, 2005

Collaborators / Contributors  Jeff Morrisette, Nazmi El Saleous (NASA GSFC)  Crystal Schaaf and Ranga Myneni (Boston University)  Steve Running and Faith Ann Heinsch (University of Montana)  Giri Palanisamy and Tammy Beaty (ORNL)

Goal  To provide subsets of MODIS Land Products in a format and spatial scale useful to field investigators Facilitates interaction between remote sensing scientists and field investigators Easily compare satellite data with ground- based measurements  Used for validation of MODIS Land Products

 Subsets of Terra and Aqua MODIS Land Products for 280 sites worldwide (field sites or flux towers) in an easy-to-use ASCII format  7 km x 7 km centered on flux tower or field sites  Two annual products, four 8-day products, two 16-day product, and calculated albedo, from 2000 to present MODIS ASCII Subsets MODIS Products Surface Reflectance Surface Temperature Land Cover NDVI / EVI LAI / fPAR Net Photosynthesis Annual NPP Albedo Reflectance – BRDF Adjusted

MODIS Subset Sites: Albedo Related BSRN Sites  Toravere, Estonia  Tateno, Japan  Payerne, Switzerland  Barrow, Alaska  S. Great Plains, Oklahoma  Fort Peck, Montana  Bondville, Illinois  Boulder Colorado  Penn State, Pennsylvania  Goodwin Creek, Mississippi Other Sites  Guzelyayla, Turkey  Ovacik, Turkey  Arabia1, Saudi Arabia  Ngotto Forest, Cent.African Rep.  RAC, Central African Republic  Nile Delta, Eqypt  Novara, Italy  Po Valley, Italy  Hapex-Sahel, Niger  Lamto, Cote D'Ivoire  Nigeria, Nigeria  Suchow, China  Mammoth Mountain, CA, USA  ARS-NE PLRC, PA, USA  Pleasant Plains, IL, USA  Allegheny Nat. Forest, PA, USA

MODIS Subset Sites: Albedo Related Greenland (Denmark)  Crawford_Point 2  Crawford_Point 1  DYE-2  JAR1  JAR2  Saddle  South Dome  SM2  Summit  ETH/CU Swiss Camp

MODIS ASCII Subset Web Site:

User-selects optical depth and szn

Albedo Calculated from MODIS BRDF Product  MODIS BRDF Albedo Model Product (MOD43B1) contains parameters for calculating albedo for visible, near-IR, and shortwave  Black Sky albedo ƒ (parm 1, parm 2, parm 3, szn)  White Sky albedo ƒ (parm 1, parm 2, parm 3)  Blue Sky albedo ƒ (white sky albedo, black sky albedo, optical thickness)

Quality Assurance  Provide quality assurance data layers Including snow Toravere BSRN, Estonia, January 1, 2005

Information at bottom of Grid Display

MODIS ASCII Subsets Web-Based Data Visualization: Grid Toravere BSRN, Estonia

Pixel Values Mean Value of Pixels Percent of Pixels that met QC Criteria Visible Broadband Blue Sky Albedo (fraction) MODIS ASCII Subsets Web-Based Data Visualization: Time Series Toravere BSRN, Estonia Year

Additional data compiled for albedo validation  Broadband Diffuse Irradiance Climatology for the selected MODIS ASCII Subset Sites (n = 254) Based on AERONET data Prepared by Privette and Hoffman Available from ORNL ftp://daac.ornl.gov/data/eos_land_val/albedo/  Subsets of Optical Depth (MOD04) for 24 sites; Summit, ETH_CU_Swiss_Camp, Tateno, Fort_Peck_Montana, Payerne, BARC, Barton_Bendish, BOREAS_BERMS, Jornada, Lake_Tahoe, Mandalgobi, Metolius_Old_Pine, Tapajos, North_Temperate_Lakes Available from NASA GSFC ftp://windhoek.nascom.nasa.gov/private/ichoku/MAPSS/

Future Plans: MODIS ASCII Subsets  Continue to offer subsets of Collection 4 MODIS Land Products from Terra and Aqua  Add Continuous Vegetation Field subsets when available  Evaluate current sites and seek additional sites for future processing / reprocessing (e.g., Collection 5 in late-2005)  To have your field site added to the MODIS Subset Collection, we need the geographic coordinates (to four significant decimal places; 10s of meters) and your commitment to share data

1 minute uncertainty yields +/- 2 km or 25 pixels Uncertainty of +/- 1 minute Need site location good to degree

Future Plans: MODIS Subset Pilot  Tool to enable on-the-fly subsetting and visualization For any area in North America up to 200 x 200 km For pre-selected sites for the rest of the world  Incorporate albedo calculation from MOD43B parameters

MODIS ASCII Subsets Web Site Contact:Bob Cook ORNL DAAC