6.3
Orographic and meteorological influences on the space-time scaling of convective precipitation
Deborah K. Nykanen, Minnesota State University, Mankato, MN; and A. Rubert Godoy
Characterizing the space-time scaling and dynamics of convective precipitation, especially in mountainous terrain, and the development of downscaling methods to transfer precipitation fields from one scale to another is the overall motivation for this research project. Space-time scale gaps continue to exist between distributed hydrologic models and numerical weather prediction (NWP) forecasts. This study attempts to address the open research problem of scaling thunderstorms and convection in mountainous terrain down to 1 ~ 4 km scales. The key objective of the study is to investigate the meteorological and orographic influences on the space-time scaling and dynamics of convective precipitation over complex topography and address the following questions: (1) does spatial and space-time scaling exist as a common feature in convective orographic precipitation?, (2) at what spatial and temporal scales do meteorological and orographic controls manifest themselves in the space-time variability of convective precipitation fields?, and (3) how does meteorological forcings and geographic location impact trends in orographic influences on the multi-scale statistical properties of convective precipitation?
In this paper, multi-scale statistical analysis will be used to study the space-time organization of several heavy convective rainfall events in mountainous terrain. Focus is placed on the Appalachian region and the Front Range of the Rocky Mountains and on linking changes in the multi-scale parameters with topographic and meteorological influences on the rainfall. Differences in geographic region and predominant orographic controls (e.g., windward versus leeward forcing) on trends in multi-scale properties of precipitation will be investigated. Several case studies of non-orographic convective precipitation events will also be included to provide insight on the linkages between multi-scale behavior and meteorological differences between storms without the presence of orographic influences. The potential for developing a statistical downscaling model for orographic convective precipitation based on the interplay between meteorological forcings and orographic influences on the multi-scale properties of orographic precipitation will be assessed.
.Session 6, Scale Issues in Weather and Climate Modeling, Including Downscaling and Validation (Room 6E)
Thursday, 15 January 2004, 1:30 PM-5:00 PM, Room 6E
Previous paper Next paper