HR: 16:35h
AN: IN24A-02    [Abstracts]
TI: Meteorological Data Interpretation as a Tool to Predict Extreme Precipitations Caused by Tropical Storms.- An Example From Santiago, Baja California Sur, Mexico
AU: * Wurl, J
EM: jwurl@uabcs.mx
AF: Universidad Autonoma de Baja CAlifornia Sur, Carretera al sur KM 5.5, La Paz, BCS 23050, Mexico
AU: Martinez Gutierrez, G
EM: martingg@uabcs.mx
AB: A statistical analysis of the climatic measurements and observations of tropical storms between 1949 and 2002 was processed to identify the effects of tropical cyclones on the climate of the Santiago region in the southern part of the peninsula of Baja California. Between May and November the peninsula is periodically affected by tropical storms, which are formed in the eastern North Pacific basin. Therefore hurricanes and other tropical storms cause an important amount of the annual precipitation on the peninsula. The area of Santiago, in its southern part, has one of the largest records of daily precipitation in Baja California Sur. Continuously since 1939 the daily precipitation was registered in at least one of the three climatic stations (Santiago, Caduaño and La Rivera). The first registrations of extreme events like tropical cyclones date from the foundation of missions in the peninsula, but a complete database which includes the position of the centre of the tropical storms starts for the Central North Pacific in 1949 (documented by the "National Hurricane Center" from the national meteorological service of the USA). The reliability of the documentation grew with the beginning of observations by satellite in the sixties. Based on the records of precipitation and a occurrence of tropical storms, a database was generated from January 1949 to December 2002. The elaborated database includes the pressure and wind speed of the tropical storms and its category, distance and direction to Santiago. Because in the eastern Pacific, up to 5 tropical cyclones were observed at the same day, only the nearest tropical storm was taken in account. The main results are that tropical storms can cause significant precipitations in the Santiago watershed up to maximum distances of 700 Km. In total 35 percent of the observed precipitation is related to tropical storms. The average precipitation on days with tropical hurricanes in distances up to 700 km was 7.10 mm. Daily precipitation of more than 100 mm was always related with the positions of a tropical storm within this distance. The Gumbel function permits to calculate the maximum expected daily precipitation within 50 years. Related to tropical cyclones a maximum of 243 mm is expected, meanwhile daily precipitation, independent from tropical cyclones, will reach only 101 mm in the same return period. This analyse of the precipitation data increases the accuracy of the hydrological balance of the Santiago watershed. The elaborated methodology allows analysing the climate in other regions of the peninsula.
DE: 0399 General or miscellaneous
DE: 1816 Estimation and forecasting
DE: 1859 Rocks: physical properties
DE: 1879 Watershed
DE: 3354 Precipitation (1854)
SC: Earth and Space Science Informatics [IN]
MN: 2007 Joint Assembly