HR: 08:00h
AN: H51G-01 INVITED     [Abstracts]
TI: Recent Analyses On The Mid Summer Drought
AU: * Magaña, V
EM: victormr@servidor.unam.mx
AF: Universidad Nacional Autónoma de México, Centro de Ciencias de la Atmosfera, UNAM Ciudad Universitaria, Mexico CIty, DF 14200, Mexico
AU: Caetano, E
EM: caetano@servidor.unam.mx
AF: Universidad Nacional Autónoma de México, Centro de Ciencias de la Atmosfera, UNAM Ciudad Universitaria, Mexico CIty, DF 14200, Mexico
AB: The Mid Summer Drought (MSD), also known as Canícula, has been a subject of interest in the scientific community in recent years. This phenomenon has been examined since the early work of climatologists in Mesoamerica. The MSD is basically a relative minimum in precipitation in the middle of the summer rainy season. The MSD signal extends from central Mexico all the way to Central America, mainly along the Pacific coast. Magaña et al (1999) has shown that the MSD is part of the annual cycle and not a form of low frequency variability. Among a number of hypotheses to explain this phenomenon, a mechanism as the thermostatic hypothesis was originally proposed by Magaña et al. (1999) However, various new mechanisms have been proposed, such as stationary circulations slowly moving and controlling the mean flow over the region. After a field campaign over the north eastern Pacific and the Caribbean warm pools, Magaña and Caetano (2005) showed that a teleconnection between these warm pools was involved in the dynamics of the MSD, and consequently, a simple column model could not explain the evolution of precipitation over the warm pools. Recently, it was found that easterly wave activity over the Caribbean Sea also showed a bimodal structure coinciding with the MSD. Even tropical cyclones in the region appear to show a bimodal structure in their temporal activity. Considering that easterly waves and tropical cyclones over the Caribbean and Mesoamerica are crucial to determine monthly rainfall the MSD dynamics seems to involve a more complex range of processes than previously thought. The implications of such recent findings in the analysis of MSD will be discussed in this work.
DE: 1812 Drought
DE: 1833 Hydroclimatology
SC: Hydrology [H]
MN: 2007 Joint Assembly