HR: 0800h
AN: H41D-0433    [Abstracts]
TI: The effect of land cover change on the convective precipitation during the growing season in the Southeastern United States
AU: * Juang, J
EM: jj19@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Porporato, A
EM: amilcare.porporato@duke.edu
AF: Department of Civil and Environmental Engineering, Duke University, Box 90287, Durham, NC 27708-0287 United States
AU: Stoy, P C
EM: pcs3@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Siqueira, M B
EM: mbs4@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Oishi, C A
EM: acoishi@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Kim, H
EM: hyunseok.kim@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Uebelherr, J
EM: joshua.uebelherr@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Katul, G G
EM: gaby@duke.edu
AF: Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, NC 27708-0328 United States
AU: Katul, G G
EM: gaby@duke.edu
AF: Department of Civil and Environmental Engineering, Duke University, Box 90287, Durham, NC 27708-0287 United States
AB: Due to the mild climate and abundant growing-season (GS) precipitation, the Southeastern United States (SE) timberland ecosystems are among the most productive ecosystems in the U.S. and act as an important carbon sink within North America. While the timberland area did not significantly change over the past 50 years, the timberland composition is undergoing significant changes. The proportion of planted pine forests (PP) to the total timberland area has dramatically increased from under 1.0% in the early 1950s to about 15.0% in 1999, and is expected to rise steadily to about 32.0% by 2040. The impact of this land-cover change on growing-season precipitation received surprisingly little attention to date. Such land-cover change may alter significantly convective precipitation during the growing season (GS). Here, we use a 7-year (1998-2004) measured water vapor and sensible heat flux record at a PP ecosystem, a 4-year record (2001-2004) from an adjacent hardwood (HW) and an old-field grassland (OF) ecosystem to investigate the possible soil moisture and atmospheric water vapor states that trigger convective precipitation during the GS. In particular, these measurements were used to investigate how eco-physiological controls on sensible heat flux affect the triggers of convective precipitation via a simple slab model for convective boundary layer growth. We showed that for a given relative humidity state, the PP ecosystem is more likely to trigger convective precipitation than HW and OF in both wet and dry soil moisture states. The broader implications of this work is that increases in PP land cover in the SE may lead to increases in convective precipitation during the growing season.
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 1632 Land cover change
DE: 1840 Hydrometeorology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: Fall Meeting 2005