Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration

Journal Article · Sun Feb 01 00:00:00 EST 2009 · Global Change Biology

OSTI ID:1015732

Hollinger, D ^[1]; Ollinger, S V ^[2]; Richardson, A D ^[2]; Martin, M E ^[3]; Meyers, T P ^[4]; Dail, D B ^[5]; Scott, N A ^[6]; Arkebauer, T J ^[7]; Baldocchi, D D ^[8]; Clark, K L ^[1]; Curtis, Peter ^[9]; Davis, K J ^[10]; Desai, Desai Ankur R ^[11]; Dragoni, Danilo ^[12]; Goulden, M L ^[13]; Gu, Lianhong ^[14]; Katul, G G ^[15]; Pallardy, Stephen G ^[16]; Pawu, K T ^[17]; Schmid, H P ^[18] ; Stoy, P C ^[19]; Suyker, A E ^[7]; Verma, Shashi ^[20]

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1. USDA Forest Service
2. University of Hew Hampshire
3. University of New Hampshire
4. NOAA ATDD
5. University of Maine
6. Queens University, Kingston, ON, Canada
7. University of Nebraska, Lincoln
8. University of California, Berkeley
9. Ohio State University, The, Columbus
10. Pennsylvania State University
11. University of Wisconsin, Madison
12. Indiana University
13. University of California, Irvine
14. ORNL
15. Duke University
16. University of Missouri
17. University of California, Davis
18. IFU, FZK IMK, Institute of Meteorology & Climate, Garmisch Partenkirchen, Germany
19. University of Edinburgh
20. University of Nebraska

Vegetation albedo is a critical component of the Earth s climate system, yet efforts to evaluate and improve albedo parameterizations in climate models have lagged relative to other aspects of model development. Here, we calculated growing season albedos for deciduous and evergreen forests, crops, and grasslands based on over 40 site-years of data from the AmeriFlux network and compared them with estimates presently used in the land surface formulations of a variety of climate models. Generally, the albedo estimates used in land surface models agreed well with this data compilation. However, a variety of models using fixed seasonal estimates of albedo overestimated the growing season albedo of northerly evergreen trees. In contrast, climatemodels that rely on a common two-stream albedo submodel provided accurate predictions of boreal needle-leaf evergreen albedo but overestimated grassland albedos. Inverse analysis showed that parameters of the two-stream model were highly correlated. Consistent with recent observations based on remotely sensed albedo, the AmeriFlux dataset demonstrated a tight linear relationship between canopy albedo and foliage nitrogen concentration (for forest vegetation: albedo 50.0110.071%N, r250.91; forests, grassland, and maize: albedo50.0210.067%N, r250.80). However, this relationship saturated at the higher nitrogen concentrations displayed by soybean foliage. We developed similar relationships between a foliar parameter used in the two-stream albedo model and foliage nitrogen concentration. These nitrogen-based relationships can serve as the basis for a new approach to land surface albedo modeling that simplifies albedo estimation while providing a link to other important ecosystem processes.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge National Environmental Research Park
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1015732
• Journal Information: Global Change Biology, Vol. 16, Issue 2; ISSN 1354-1013
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALBEDO
CLIMATE MODELS
CLIMATES
CROPS
DATA COMPILATION
ECOSYSTEMS
FORESTS
LEAVES
MAIZE
NITROGEN
PLANTS
RANGELANDS
SEASONS
SIMULATION
SOYBEANS
TREES
albedo
nitrogen
vegetation