HR: 0800h
AN: H41D-0428    [Abstracts]
TI: Dynamic Precipitation Recycling Model - Small Timescales Reveal new Land/Atmosphere Interactions
AU: * Dominguez, F
EM: dominguz@uiuc.edu
AF: University of Illlinois at Urbana-Champaign, Hydrosystems Lab 205 N. Mathews Ave. , Urbana, IL 61801 United States
AU: Kumar, P
EM: kumar1@uiuc.edu
AF: University of Illlinois at Urbana-Champaign, Hydrosystems Lab 205 N. Mathews Ave. , Urbana, IL 61801 United States
AB: The present work focuses on precipitation recycling, or the contribution of local evapotranspiration to precipitation events. Computations of precipitation recycling using analytical models are generally performed under the assumption of negligible change in moisture storage in the atmospheric column. Because the moisture storage term is non-negligible at smaller time scales, most recycling studies using analytical models are done at monthly or longer time scales. We present a new dynamic precipitation recycling model that incorporates the change in moisture storage. It is derived formally from the conservation of mass equation, and presented in a simple and computationally efficient form. This model allows for recycling analysis at a range of temporal scales, from daily to monthly and longer, unveiling complex relationships between recycling calculated at different scales. At a daily timescale, new links between precipitation recycling and the components of the water budget emerge. Using Reanalysis II (R-II) data, we show that evapotranspiration and the recycling ratio are not monotonically increasing/decreasing functions of precipitation. Furthermore, the daily analysis enables us to study the conditions that modulate recycling in terms of the thermodynamic structure and the humidity of the overlying atmosphere. We will also present an analysis of precipitation recycling from an ecosystem perspective. Recycling calculations are performed on selected ecological regions of the US, each presenting similar long-term climate, vegetation, soil, physiographic and land use characteristics. We focus on the characteristic scales of convection that trigger precipitation. North American Regional Reanalysis (NARR) data is used, as it provides higher spatial resolution required for this type of analysis. The results from the ecosystem perspective enable us to better understand how the land surface characteristics of a region affect the recycling process. This serves as a first approach to study precipitation recycling and the role it plays within a vegetated surface.
DE: 1622 Earth system modeling (1225)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1818 Evapotranspiration
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: Fall Meeting 2005