HR: 11:50h
AN: GC52A-10    [Abstracts]
TI: Climate management through agricultural albedo manipulation
AU: * Doughty, C E
EM: cdoughty@uci.edu
AF: Department of Earth System Science University of California, Irvine, Department of Earth System Science University of California, Irvine Croul Hall, Irvine, Ca 92697-3100, United States
AU: McMillan, A
EM: mcmillaa@uci.edu
AF: Department of Earth System Science University of California, Irvine, Department of Earth System Science University of California, Irvine Croul Hall, Irvine, Ca 92697-3100, United States
AU: Goulden, M
EM: mgoulden@uci.edu
AF: Department of Earth System Science University of California, Irvine, Department of Earth System Science University of California, Irvine Croul Hall, Irvine, Ca 92697-3100, United States
AB: Agriculture is the largest land surface that people actively manipulate, and it could be adversely affected by increased temperatures due to global warming. Crop species, already efficient reflectors of near infrared (NIR) radiation, could be modified to be even more reflective with the aim of causing albedo driven cooling. Agricultural scientists have bred soybean varieties with a fourfold increase in pubescence (leaf hairs) that increases shortwave reflectivity by 3-5%. We used NCAR's community atmosphere model (CAM) coupled to the community land model (CLM) to understand the effect on climate of a worldwide replacement of agriculture with crop varieties 3-5% more reflective in the shortwave. Increasing reflectance significantly decreases daily maximum temperature by an average of 1.85 ° C in agricultural regions above 30 ° latitude where lower vapor pressure deficits (VPD) cause the energy lost from increased reflectivity to be lost as sensible heat instead of latent heat. However, in latitudes between 10-30 ° N and S there are few significant temperature changes because higher vapor pressure deficits decrease latent heat, which decreases cloud formation and increased solar radiation absorbed by agricultural systems.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0402 Agricultural systems
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0429 Climate dynamics (1620)
DE: 1622 Earth system modeling (1225)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting