HR: 09:25h
AN: H31E-05    [Abstracts]
TI: Hydroclimatic variability in the North American Monsoon region of northwest Mexico
AU: * Gochis, D J
EM: gochis@rap.ucar.edu
AF: National Center for Atmospheric Research, 3450 Mitchell Lane, Boulder, CO 80304, United States
AU: Brito-Castillo, L
EM: lbrito04@cibnor.mx
AF: Centro de Investigaciones Biologicas del Noroeste, Carreter a Las Tinajas P.O. Box 349, Guaymas, Son , Mexico
AB: River systems in southwestern North America exhibit a strong gradient in their seasonal runoff climatologies which are attributed to regional transitions in climatic forcing. Those basins draining the Sierra Madre Occidental of western Mexico are strongly influenced by summer monsoon rainfall while river systems in the southern and central Rocky Mountains are largely snowmelt or cool-season dominated. While much research has focused on the interannual variability of streamflow in snow-melt dominated basins in the U.S., comparatively less research has documented the interannual variability and long-term changes in summer streamflow in northwest Mexico. In this work, interannual variations in regionalized streamflow and rainfall-runoff relationships from northwest Mexico are explored. Long term trends between summer and cool-season streamflow exhibit markedly different structures in some regions. Partitioning between cool season and warm season streamflow shows a marked transition in correspondence with the 1976-1977 climate regime shift as well as significant interannual modulation that appears to be linked to ENSO. Similarly, significant changes in the fraction of seasonal streamflow to seasonal rainfall (ie runoff fractions) exhibit an ENSO-like influence. Recent work on characterizing the relationship between seasonal precipitation structures across the SMO and runoff responses during both the warm and cool seasons will be presented.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1833 Hydroclimatology
DE: 1840 Hydrometeorology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
SC: Hydrology [H]
MN: 2007 Joint Assembly