Linkages between snow cover, temperature and rainfall and the North Atlantic Oscillation over Morocco

Climate Research

L. Hanich¹  A. Boudhar¹  Y. Tramblay¹  A. Marchane¹  L. Jarlan¹ 

关键词: Snow cover;    MODIS;    NAO;    Semi-arid;    Mediterranean areas;   

DOI  :  10.3354/cr01409

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: Snowpack significantly contributes to water resources in North Africa. The objective of this work was to analyze the impact of the North Atlantic Oscillation (NAO) on rainfall and temperature in Morocco at a sub-seasonal scale and to evaluate, for the first time, linkages between the NAO and snow cover area (SCA) derived from remote sensing observations. For this purpose, we analyzed daily SCA products (2000-2013) from the MODIS sensor, meteorological data from 37 stations (1993-2011), NCEP re-analysis of surface air temperature and rainfall rate, and a monthly NAO index. The linear linkages sought using simple correlation analysis demonstrated that negative (positive) NAO (1) is associated with enhanced (reduced) rainfall in December and February for the northern part of the country; (2) occurs with above-normal (below-normal) temperature and, in contrast with rainfall, the correlation persists far inland and late in the season. These results highlight a possible competing influence of NAO on the snowpack dynamic through rainfall and temperature. Indeed, negative (positive) NAO tends to favor earlier (later) melting and lesser (greater) SCA in spring (April-May) through milder temperatures. Results have direct implications for seasonal forecast of SCA in Morocco.

【 授权许可】

Unknown