HR: 15:10h
AN: H23H-07    [Abstracts]
TI: Relations between Soil Moisture and Precipitation in the U.S. Midwest: A Long-term Climatic Study
AU: * Over, T M
EM: tmover@eiu.edu
AF: Eastern Illinois University, Department of Geology / Geography, 600 Lincoln Ave., Charleston, IL 61920 United States
AU: D'Odorico, P
EM: paolo@virginia.edu
AF: University of Virginia, Department of Environmental Sciences, PO Box 400123, Clark Hall, Charlottesville, VA 22904 United States
AU: Kunkel, K
EM: kkunkel@sws.uiuc.edu
AF: Illinois State Water Survey, Center for Atmospheric Science, 2204 Griffith Dr., Champaign, IL 61820 United States
AU: Zhang, Y
EM: yanzhang@princeton.edu
AF: Princeton University, Department of Civil and Environmental, Engineering C330 Engineering Quad, Princeton, NJ 08544 United States
AB: It has long been recognized that soil moisture plays an important role in regional climate, especially during summer. In particular, there is usually observed a positive correlation between soil moisture and subsequent precipitation in the same region. However, this phenomenon has not been well quantified, especially over long time periods. Furthermore, most studies in this region have relied on soil moisture measurements made under sod, whereas the primary land use is corn and soybean agriculture. In the present study, a 50-year (1951-2000) modeled soil moisture dataset driven by observed weather variables including daily precipitation measurements for five states in the U.S. Midwest are used to quantify the dependence of precipitation statistics on previous soil moisture during the months of May to September. The relations between daily precipitation frequency and depth in the 14 to 28-day windows following each day of modeled relative soil moisture in the top 50 cm of soil are examined. A significant positive relation between soil moisture and frequency of precipitation is found in all climate divisions and for all window lengths. The relation between soil moisture and storm depth is weaker though usually still significant and positive. The regression slopes tend to decrease slightly as the analysis window lengthens. Dependence of these statistics on month-of-the-year, depth of soil being considered, and other factors will be explored. Implications of the results for identifying and quantifying feedbacks between soil moisture and precipitation will be considered.
DE: 1818 Evapotranspiration
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1854 Precipitation (3354)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: Fall Meeting 2005