HR: 08:50h
AN: H31E-03 INVITED     [Abstracts]
TI: Precipitation Recycling: a Mechanism for Hydroclimatological Stability in the North American Monsoon Region
AU: * Dominguez, F
EM: francina@hwr.arizona.edu
AF: University of Arizona, 845 N. Park Marshall Building, 5th Floor, Tucson, AZ 86701, United States
AU: Kumar, P
EM: kumar1@uiuc.edu
AF: University of Illinois, 205 N. Mathews Ave, Urbana, IL 61801, United States
AU: Vivoni, E
EM: vivoni@nmt.edu
AF: New Mexico Tech, MSEC 244 Dept. of Earth and Environmental Science, Socorro, NM 87801, United States
AB: In this work we study precipitation recycling as part of the dynamic North American Monsoon System (NAMS), using a set of land-atmosphere variables derived from North American Regional Recycling (NARR) data. The recycling ratio is estimated using the Dynamic Recycling Model which provides recycling estimates at daily timescales. We show that precipitation recycling is a significant source of moisture for monsoon precipitation, with recycling ratios consistently above 15% and sometimes as high as 25%. The 1985-1995 climatological analysis of NAMS precipitation recycling reveals a positive feedback mechanism between monsoon precipitation and subsequent increase in precipitation of recycled origin. One of the innovative features of this analysis is the delineation of the source and sink regions of recycled precipitation within the NAMS domain. While monsoon precipitation and evapotranspiration are predominantly located in the seasonally dry tropical forests in the southwestern part of the domain, recycling is enhanced northeast of this region, indicating a relocation of soil moisture further inland to drier regions in the northeast. Interestingly, the three years with longest monsoons in the 11-year period present an a-synchronous pattern between precipitation and recycling ratio. The longest monsoons have a characteristic double peak in precipitation, with enhanced recycling ratios during the intermediate dry period. Indicating that, even when large scale moisture advection decreases, evapotranspiration keeps providing moisture to the overlying atmosphere and contributing to precipitation. Through the negative feedback present during long monsoons and by relocation of soil moisture, precipitation recycling brings favorable conditions for vegetation sustenance in the NAMS region.
DE: 1813 Eco-hydrology
DE: 1833 Hydroclimatology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1866 Soil moisture
DE: 1878 Water/energy interactions (0495)
SC: Hydrology [H]
MN: 2007 Joint Assembly