Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Mexique → Maestría → Evaluación de los efectos del ENSO sobre las lluvias de Baja California Sur, con énfasis en ciudades costeras y cuencas hidrológicas

Centro de Investigaciones Biológicas del Noroeste (CIBNOR) 2005

Evaluación de los efectos del ENSO sobre las lluvias de Baja California Sur, con énfasis en ciudades costeras y cuencas hidrológicas

Osorio Ayala, Francisco Leonardo

Titre : Evaluación de los efectos del ENSO sobre las lluvias de Baja California Sur, con énfasis en ciudades costeras y cuencas hidrológicas

Auteur : Osorio Ayala, Francisco Leonardo

Etablissement de soutenance : Centro de Investigaciones Biológicas del Noroeste (CIBNOR)

Grade : Maestría en Ciencias en el Uso, Manejo y Preservación de los Recursos Naturales 2005

Résumé
In coastal cities like La Paz and Cabo San Lucas, in Baja California Sur, management of coastal zones, civil protection and prevention of contingencies are activities that require knowledge of ENSO influence over temporal and spatial rainfall variability. The objective of this work was to understand this influence to focus on the effects over rainfalls in coastal cities in Baja California Sur. With data precipitation of 97 climate stations obtained from Comisión Nacional del Agua (CNA), Servicio Meteorológico Nacional (SMN), Centro de Investigaciones Biológicas del Noroeste (CIBNOR) and International Research Institute for Climate Prediction (IRI), we studied the ENSO effect under two different scenarios. Scenario A consisted on obtaining the average rainfall from El Niño years between 1950 and 1990 for each climatic series, while, scenario B consisted on obtaining the average rainfall from the most intense El Niño years between 1950 and 2003. The average obtained, in each case was compared with the Norm of the climate station and the anomalies were estimated. The Norm of the station is the total average of rainfall series in the period from 1950 to 1990. The same calculations were done for La Niña years and for all climate stations. Calculations were done for the series of total annual rainfall (June-May), total rainfall in the warm season (May-October), in the cold season (November-April) and monthly series. Additionally, land profiles (crosswise and lengthwise), and composite maps of geopotential height anomalies at different levels were constructed. For La Paz and Los Cabos (San Jose del Cabo and Cabo San Lucas), the influence of an El Niño year, result in more annual rainfall in La Paz and less annual rainfall in Los Cabos. The opposite occurs in a La Niña year. These results are consistent in summer. In winter, the ENSO effect is more uniform, with above normal rainfall in Baja California Sur during El Niño and under normal rainfall during La Niña. In addition, there is a very marked differentiation in both sides of the peninsular watershed. In ENSO conditions, moisture penetration toward the slopes of the Gulf of California and the Pacific Ocean causes the tendencies of rainfall anomalies to be with opposite sign, if they are compared between both slopes as if they are compared between El Niño and La Niña events. In order to explain the distinctive characteristics of rainfall distribution, we took into consideration the relief and the atmosphere flow patterns at different levels of geopotential heights ; this procedure, allowed us to obtain some light to the problem and the necessity to incorporate other factors involved in the generation of rainfall over the study area, such as moisture transportation mechanisms from the Gulf of California, influence of the Pacific Decadal Oscillation (PDO), local marine currents, winds and tropical cyclones for subsequent studies.

Mots Clés : ENSO ; precipitación ; lluvias ; ciudades costeras ; cuencas hidrológicas ; Baja California Sur

Présentation (3,38 Mb)

Version intégrale

Page publiée le 7 décembre 2017