# Presentation: 160184

## MODIS Surface Albedos and Distribution of Global Ecosystem Types

*Eric G. Moody**1,2**, Michael D. King**1**, Steven Platnick**1,3**, Crystal Schaff**4*
*1*NASA Goddard Space Flight Center
*2*Emergent IT, Inc.
*3*University of Maryland Baltimore County
*4*Boston University
- Outline
-  Motivation
-  Issues with original albedo scheme
-  New Ecosystem-Albedo seasonal model
-  Description of ecosystem classifications
-  Implementation of new model
-  Summary and future directions

## Motivation

- Retrieval of Cloud Optical Properties (MOD06OD)
- Computes optical thickness and effective radius using White-Sky surface albedos at wavelengths of 0.659, 0.865, 1.24, 			1.6, 2.1, and 3.7 microns.
- Inaccurate albedo value will	enhance or attenuate reflectance.
- Can cause retrieval failures and unreasonable/unphysical results.
- Preparation for consistent year processing.
- Pre- and post-launch White Sky Surface Albedo scheme flagged for update.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Original Albedo Scheme

- Scheme used IGBP ecosystem classifications as a surrogate for albedo.
- eg. Table of albedos for each ecosystem.
- Albedo data obtained from CERES/SARB.
- Issues with the scheme:
- Broad-banded data.
- Led to key bands having same surface albedo.
- No seasonal variation in albedo.
- Ecosystem with growth cycles not represented.
- Coarse resolution CERES IGBP global ecosystem map.
- 1 degree resolution left signatures

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Design Parameters

- Fine resolution (10km) IGBP ecosystem and albedo data.
- Albedos at wavelengths of interest.
- Seasonally dependent albedo data set.
- Sufficient data to generate global albedo maps.
- 			-OR-
- Sufficient data to create an ecosystem-albedo surrogate.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## MODIS-Land Products.

- Drs. Alan Strahler and Crystal Schaaf
- Boson Univ. Center for BRDF/Albedo Research
- MOD12 - Ecosystem Classification
- 10 km resolution, globally.
- Includes updates of IGBP classifications.
- MOD43B - BRDF/Albedo Product
- 10 km resolution, 16-day global composites.
- Includes White-Sky Albedos at 			specific wavelengths of interest.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Sufficient  Data Available?

- NO (at the time of consistent year code delivery).
- Only 2 data sets certified for quantitative use.
- Spanned October, 2000.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Preliminary Analysis.

- Create seasonal ecosystem-albedo scheme if:
- Northern and Southern Hemispheres differ statistically.
- Sufficient data samples for each ecosystem type.
- Ecosystem-Albedo correlate.
- Analysis
- Compute statistics for “latitude belts” of varying sizes
- Mean, standard deviation, and sample size
- Albedos at various wavelengths, for each ecosystem type.
- Results
- All three criteria met.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Model Description.

- Tropics, no seasonal effect.
- Seasonally dependant.
- Transition region.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Model Data.

- Seasonally Dependent Regions.
- Northern Hemisphere values assumed to be winter albedos at the winter solstice.
- Southern Hemisphere values assumed to be summer albedos at the summer solstice.
- Sinusoidal fit of these albedos to simulate seasonality.
- Tropical Region (no seasonal effects)
- Albedos at various bands computed			 for ecosystem types
- Transition Region (some seasonal effects)
- Linear fit between tropical and north/south albedos.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## IGBP Ecosystem Classifications

- Forests:
- Evergreen Needle and Broadleaf, Deciduous Needle and Broadleaf, and Mixed
- “Savannas”
- Closed and Open Shrublands, Woody Savanna, Savanna, Grasslands
- Other Vegetation
- Permanent Wetlands, Urban and Buildup, Cropland and Cropland Mosaics
- Miscellaneous:
- Permanent Snow/Ice, Tundra, Barren/Sparse, and Water Bodies

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Global Ecosystem  Distribution

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Forest Ecosystem Distribution

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Savanna Ecosystem Distribution

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Other Vegetation Distribution

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Miscellaneous Distributions

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 16

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 17

- Eric.Moody@GSFC.NASA.gov

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## Slide 18

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 19

- Eric.Moody@GSFC.NASA.gov

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## Slide 20

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 21

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 22

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 23

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 24

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 25

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 26

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Standard Deviations.

- Albedo means at various wavelengths and times of year, for all ecosystem types, are within 7%.
- Majority are within 3%
- Suggests a reasonable correlation between ecosystem and albedo.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Slide 28

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Albedo Movies

- _Albedo Movies_
- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- _Ecosystem Color Scheme_
- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Ecosystem Color Scheme

- _Ecosystem Color Scheme_
- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- _Albedo Movies_
- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Albedo Movies

- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- _Ecosystem Color Scheme_
- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Ecosystem Color Scheme

- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- _Albedo Movies_
- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Albedo Movies

- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- _Ecosystem Color Scheme_
- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Ecosystem Color Scheme

- Pink = Crops
- Green = Trees
- Yellows = Barren/Deserts
- Blues = Savannas

- _Albedo Movies_
- Loops through bands 0.65, 0.86,
-                 1.24, 1.64, 2.1, and 3.7
- Loops through seasonal equinox
-    and solstice, progressing from
-    Julian days 91, 173, 293, 356

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Conclusions

- Improved surface albedo data for use in consistent year processing.
- Provided albedo and ecosystem data sets at a finer resolution.
- Added seasonal variability.
- Provided albedos at specific wavelengths of interest.
- Ecosystem can be used as a surrogate for albedo.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody

## Future Directions

- Use a full year’s data (from consistent year) to improve ecosystem and albedo statistics.
- Investigate global albedo maps.
- Investigate ecosystem-albedo surrogate.
- ISRSE presentation, April 2002.
- Publish this work with BU group.

- Eric.Moody@GSFC.NASA.gov

- Eric G. Moody