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Title: Regional climate effects of irrigation and urbanization in thewestern united states: a model intercomparison

Abstract

In the western United States, more than 30,500 square miles has been converted to irrigated agriculture and urban areas. This study compares the climate responses of four regional climate models (RCMs) to these past land-use changes. The RCMs used two contrasting land cover distributions: potential natural vegetation, and modern land cover that includes agriculture and urban areas. Three of the RCMs represented irrigation by supplementing soil moisture, producing large decreases in August mean (-2.5 F to -5.6 F) and maximum (-5.2 F to -10.1 F) 2-meter temperatures where natural vegetation was converted to irrigated agriculture. Conversion to irrigated agriculture also resulted in large increases in relative humidity (9 percent 36 percent absolute change). Only one of the RCMs produced increases in summer minimum temperature. Converting natural vegetation to urban land cover produced modest but discernable climate effects in all models, with the magnitude of the effects dependent upon the preexisting vegetation type. Overall, the RCM results indicate that land use change impacts are most pronounced during the summer months, when surface heating is strongest and differences in surface moisture between irrigated land and natural vegetation are largest. The irrigation effect on summer maximum temperatures is comparable in magnitude (but oppositemore » in sign) to predicted future temperature change due to increasing greenhouse gas concentrations.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
COLLABORATION - UC Santa Cruz; ScrippsInstitute of Oceanography; USGS; UC Davis
OSTI Identifier:
893610
Report Number(s):
LBNL-60284; CEC-500-2006-031
R&D Project: G2W020; TRN: US200625%%430
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AGRICULTURE; CLIMATE MODELS; CLIMATES; GREENHOUSE GASES; HEATING; HUMIDITY; IRRIGATION; LAND USE; MOISTURE; PLANTS; SOILS; URBAN AREAS

Citation Formats

Snyder, M.A., Kueppers, L.M., Sloan, L.C., Cavan, D.C., Jin, J., Kanamaru, H., Miller, N.L., Tyree, M., Du, H., and Weare, B. Regional climate effects of irrigation and urbanization in thewestern united states: a model intercomparison. United States: N. p., 2006. Web. doi:10.2172/893610.
Snyder, M.A., Kueppers, L.M., Sloan, L.C., Cavan, D.C., Jin, J., Kanamaru, H., Miller, N.L., Tyree, M., Du, H., & Weare, B. Regional climate effects of irrigation and urbanization in thewestern united states: a model intercomparison. United States. doi:10.2172/893610.
Snyder, M.A., Kueppers, L.M., Sloan, L.C., Cavan, D.C., Jin, J., Kanamaru, H., Miller, N.L., Tyree, M., Du, H., and Weare, B. Mon . "Regional climate effects of irrigation and urbanization in thewestern united states: a model intercomparison". United States. doi:10.2172/893610. https://www.osti.gov/servlets/purl/893610.
@article{osti_893610,
title = {Regional climate effects of irrigation and urbanization in thewestern united states: a model intercomparison},
author = {Snyder, M.A. and Kueppers, L.M. and Sloan, L.C. and Cavan, D.C. and Jin, J. and Kanamaru, H. and Miller, N.L. and Tyree, M. and Du, H. and Weare, B.},
abstractNote = {In the western United States, more than 30,500 square miles has been converted to irrigated agriculture and urban areas. This study compares the climate responses of four regional climate models (RCMs) to these past land-use changes. The RCMs used two contrasting land cover distributions: potential natural vegetation, and modern land cover that includes agriculture and urban areas. Three of the RCMs represented irrigation by supplementing soil moisture, producing large decreases in August mean (-2.5 F to -5.6 F) and maximum (-5.2 F to -10.1 F) 2-meter temperatures where natural vegetation was converted to irrigated agriculture. Conversion to irrigated agriculture also resulted in large increases in relative humidity (9 percent 36 percent absolute change). Only one of the RCMs produced increases in summer minimum temperature. Converting natural vegetation to urban land cover produced modest but discernable climate effects in all models, with the magnitude of the effects dependent upon the preexisting vegetation type. Overall, the RCM results indicate that land use change impacts are most pronounced during the summer months, when surface heating is strongest and differences in surface moisture between irrigated land and natural vegetation are largest. The irrigation effect on summer maximum temperatures is comparable in magnitude (but opposite in sign) to predicted future temperature change due to increasing greenhouse gas concentrations.},
doi = {10.2172/893610},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}

Technical Report:

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