13th Conference on Applied Climatology and the 10th Conference on Aviation, Range, and Aerospace Meteorology

Wednesday, 15 May 2002: 3:45 PM
Land use change and modification of near surface temperature records in the Northern Great Plains: verification of modeling results
Rezaul Mahmood, Western Kentucky Univ., Bowling Green, KY; and K. G. Hubbard and C. Carlson
Land use and land cover change can modify near surface atmospheric condition. Mesoscale modeling studies have shown that modification in land use affects near surface soil moisture storage and energy balance. Such a study in the Great Plains showed that changes in land use from natural grass to irrigated agriculture enhanced soil water storage in the root zone and increased latent energy flux. This increase in latent energy flux would correspond to a decrease in sensible heat flux and therefore modify near surface temperature records. To verify this deduction, we have investigated the changes in the historical near surface temperature records in Nebraska, USA. We have analyzed the long-term mean monthly maximum, minimum, and monthly mean air temperature data from 5 irrigated and 4 non-irrigated sites. The cooperative weather observation (coop) network is the source of the data. We have found that there is a clear trend in decreasing mean maximum and average temperature data for irrigated sites. The results from non-irrigated sites indicated an increasing trend for the same parameters. In addition, we have conducted similar analyses of temperature data for the National Climatic Data Center's (NCDC) Historical Climatic Network (HCN) data set for the same locations. The results are similar to that obtained with the coop data set. Further investigation of dew point temperature records for irrigated and non-irrigated sites also show an increasing and decreasing trend, respectively. Therefore, we conclude that the land use change in the Great Plains has modified near surface temperature records.

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