Thursday, 26 January 2012
Predictability of Flooding Events in Southern Mexico
Hall E (New Orleans Convention Center )
Two thirds of available water resources in Mexico are located on the southern part of the country. The spatial distribution and temporal variability of available water resources is closely linked to precipitation events occurred over steep topography areas and regions affected by the Atlantic and Pacific tropical storms and hurricanes. Hydrometeorological events such as flooding have often caused huge socio-economic losses to southern Mexican states such as Tabasco, Chiapas, and Veracruz among others. Recently, the Mexican government has incentivized improvements in scientific research and technological development to better understand the hydroclimatological processes and the improvement of the current hydrometeorological forecasting tools in the region. As part of the initial stages of the mentioned endeavors, the present study aims to assess the prevalent surface hydrologic conditions associated with flooding events over 1925 to 2008 in the Grijalva River Basin, located in the Mexican states of Tabasco Chiapas and the Republic of Guatemala. We created a consistent long term data set (over 1925-2008) of streamflow, soil moisture and evapo-transpiration for the Grijalva River Basin using the Variable Infiltration Capacity (VIC) model. The model was forced with historical precipitation, minimum and maximum temperature, and wind speed data and was calibrated against the observed streamflow data for the basin. To examine the influence of climate variability on surface hydrology during flooding events we considered wet years to be the years with simulated streamflows above percentile 90th at four stations along the Grijalva River. Assuming streamflow as an integrative hydrological variable we assessed the correlation between simulated monthly streamflows and the Monthly Bivariate ENSO Time Series (BEST) Index. Preliminary results show a positive correlation between wet years and La Niņa conditions. The assessment of the spatial distribution and temporal variability of simulated surface hydrological variables provides elements to understand some of the links between major flooding events at the low-altitude plains of the Grijalva River basin and large-scale climate phenomena such as La Niņa.
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