Observational estimates of radiative forcing due to land use change in southwest Australia

Udaysankar S Nair; Deepak K Ray; Jun Wang; Sundar A Christopher; Tom J Lyons; Ronald M Welch; R. A Pielke

doi:10.1029/2006JD007505

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Observational estimates of radiative forcing due to land use change in southwest Australia

Journal article

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Observational estimates of radiative forcing due to land use change in southwest Australia

Udaysankar S Nair, Deepak K Ray, Jun Wang, Sundar A Christopher, Tom J Lyons, Ronald M Welch and R. A Pielke

Journal of Geophysical Research: Atmospheres, Vol.112(D9), pp.D09117-n/a

05/16/2007

DOI: 10.1029/2006JD007505

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Abstract

Radiative forcing associated with land use change is largely derived from global circulation models (GCM), and the accuracy of these estimates depends on the robustness of the vegetation characterization used in the GCMs. In this study, we use observations from the Clouds and Earth's Radiant Energy System (CERES) instrument on board the Terra satellite to report top‐of‐the‐atmosphere (TOA) radiative forcing values associated with clearing of native vegetation for agricultural purposes in southwest Australia. Over agricultural areas, observations show consistently higher shortwave fluxes at the TOA compared to native vegetation, especially during the time period between harvest and planting. Estimates using CERES observations show that over a specific area originally covered by native vegetation, replacement of half the area by croplands results in a diurnally averaged shortwave radiative forcing of approximately −7 W m−2. GCM‐derived estimates for areas with 30% or more croplands range from −1 to −2 W m−2 compared to observational estimate of −4.2 W m−2, thus significantly underestimating radiative forcing due to land use change by a factor of 2 or more. Two potential reasons for this underestimation are incorrect specification of the multiyear land use change scenario and the inaccurate prescription of seasonal cycles of crops in GCMs.

Australia

land use change

radiative forcing

Details

Title: Subtitle: Observational estimates of radiative forcing due to land use change in southwest Australia
Creators: Udaysankar S Nair - University of Alabama
Deepak K Ray - University of Alabama
Jun Wang - University of Alabama
Sundar A Christopher - University of Alabama
Tom J Lyons - Murdoch University
Ronald M Welch - University of Alabama
R. A Pielke - Colorado State University
Resource Type: Journal article
Publication Details: Journal of Geophysical Research: Atmospheres, Vol.112(D9), pp.D09117-n/a
DOI: 10.1029/2006JD007505
ISSN: 0148-0227
eISSN: 2156-2202
Number of pages: 8
Language: English
Date published: 05/16/2007
Academic Unit: Electrical and Computer Engineering; Civil and Environmental Engineering; Physics and Astronomy; Chemical and Biochemical Engineering
Record Identifier: 9984104812602771

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