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Update on Albedo Look-up Map

Update on Albedo Look-up Map. I. Generated albedo LUMs based on BU climatology land cover map (v5.1) (hierarchical approach) wsa and bsa monthly IGBP class based snow-free and snow-covered vis , nir and shortwave broadbands

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Update on Albedo Look-up Map

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  1. Update on Albedo Look-up Map I. Generated albedo LUMs based on BU climatology land cover map (v5.1) (hierarchical approach) • wsa and bsa • monthly • IGBP class based • snow-free and snow-covered • vis, nir and shortwave broadbands • 0.05, 0.10, 0.25, 0.50, 1.0, 2.5, 5.0, 10.0, 20.0, 30.0, 60.0, 90.0 and 180.0 degrees • Unfilled (one resolution) and filled (hierarchical resolution) II. Built snow-covered albedo at 30 arcsec based on BU land cover (neighbor searching approach) • v1 used good quality only - more gaps • v2 accepts both good and the mixed quality - less gaps

  2. MODIS IGBP Land Cover BU v5.1 2001-2009 500m majority IGBP (c5) Most IGBP classes are similar but observed changes in: - 10 (grasslands), 12 (croplands) and 14 (cropland/natural veg) - 1 (ENF) and 5 (MF)

  3. Version 1 snow-free albedo LUM (hierarchical) (pixel resolution varies from 0.05 to 20 degrees) 0 0.1 0.2 Grassland, wsa_shortwave, 0.05 degree, August)

  4. Version 2 snow-free albedo LUM (hierarchical)(pixel resolution varies from 0.05 to 60 degrees) 0 0.1 0.2 Grassland, wsa_shortwave, 0.05 degree, August)

  5. Version 2 snow-free albedo LUM (unfilled)(All pixelsare in 0.05 degree) 0 0.1 0.2 Grassland, wsa_shortwave, 0.05 degree, August)

  6. Modeled white-sky albedo for shortwave band on August (0.05°) Based on Version 1 LUMs (filled) and BU IGBP map 0 0.1 0.2 0.3

  7. Modeled white-sky albedo for shortwave band on August (0.05°) Based on Version 2 LUMs (filled) and BU IGBP map 0 0.1 0.2 0.3

  8. Climatology white-sky albedo for shortwave band on August (0.05°) 0 0.1 0.2 0.3

  9. Climatology Albedo Modeled Albedo Modeled Snow-free WSA Shortwave August 0.05 degree Climatology

  10. Modeled snow-covered white-sky albedo in January based on version 1 (assume snow occurs globally) 0 0.1 0.2 0.3 0.4 0.5

  11. Modeled snow-covered white-sky albedo in January based on version 2 (assume snow occurs globally) 0 0.1 0.2 0.3 0.4 0.5

  12. Climatology snow-covered white-sky albedo in January North America Modeled Climatology 0 0.1 0.2 0.3 0.4 0.5

  13. Uncertainty of modeled snow-covered white-sky albedo in January from version 1 0 0.05 0.10

  14. Summary I • Version 2 includes both unfilled (uniform pixel resolution) and gap-filled (hierarchical resolution) LUMs • Modeled albedo agree with climatology albedo (verification) • Uncertainties of modeled albedo are smaller when climatology albedo are available at the local scale (finer pixel resolution).

  15. II. Snow-covered albedo at 30 arcsec based on neighbor searching approach • Data • MODIS 30” CMG BRDF (MCD43D) from 2000 to 2012 • IGBP 30” CMG land cover map • Methodology • BRDF and QC -> broadband snow albedo (BSA and WSA) • 16 day data -> monthly average • Multiyear stats of monthly snow albedo for each surface type • Spatial average (21-by-21 or 31-by-31 pixels) • Output • Stats of BSA and WSA for three broadbands (SW, NIR, and VIS): mean, max, and min

  16. Jan Feb Jan Feb Mar Apr Mar Apr May Jun May Jun Global snow albedo climatology: monthly mean snow shortwave BSA in 13 years

  17. Jul Aug Sep Oct Nov Dec Global snow albedo climatology: monthly mean snow shortwave BSA in 13 years

  18. ENF EBF DNF DBF MIX CSH OSH WSV Snow shortwave albedo climatology for each of the IGBP land cover types for March

  19. SAV GRA WET CRC URB CRN GLA BRN Snow shortwave albedo climatology for each of the IGBP land cover types for March

  20. Summary II • There is 50% increase in number of pixels with snow covered albedo values by including the qc flags 0 & 1; • Snow albedo is more class-dependent and the within-class variation is much smaller using the multiyear stable classification map.

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