Rainfall Generated By The Incidence Of Two Simultaneous Tropical Cyclones In Mexico

Abstract:

The objective of this study is to characterize the registered rainfall originated from the simultaneous incidence of two tropical cyclones in Mexico, during September 2013. Tropical Storm Manuel in the Pacific and Hurricane Ingrid (category 1) in the Gulf of Mexico, made landfall during a 24 hours period on September 15 and 18, 2013. Both systems, affected 77% of Mexican territory with heavy rainfall producing landslides and severe flooding. The unprecedented occurrence of two simultaneous tropical cyclones, along with the large damages registered in the country; make evident the need for a careful examination of the rainfall produced by their simultaneous incidence. For this, we utilize information from the Tropical Rainfall Measurement Mission (TRMM), in combination with data from the rain gauge observations (from 1^st to 16^th September 2013). The selected remotely sensed products correspond to the TRMM Multi-Satellite Precipitation Analysis (TMPA), 3B42RT and 3B42V7. Additionally, we estimate the performance of the TRMM products through well-known error metrics derived from the comparison of both, registered rainfall by rain gauges and that determined from 607 TMPA cells (0.25° x 0.25° containing at least one rain gauge). Results show that rainfall produced by the incidence of both storms, is similar to that registered as if the events occurred separately, accounting for about 10% of the annual precipitation total of 2013. Moreover, spatially averaged results indicate that the product 3B42V7 is a good estimate of daily precipitation across the country, while the TMPA 3B42RT product underestimates the amount of rainfall due to cyclonic events. Therefore, TMPA products provide acceptable estimates of rainfall for large-scale cyclonic events.