Study of seasonal-scale atmospheric water cycle with ground-based GPS receivers, radiosondes and NWP models over Morocco

Date

2011

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

This study investigates the seasonal variation of precipitable water vapor, moisture transport and precipitation over Morocco and the Canary Islands using data from ground-based GPS receivers, radiosondes, GPCP and NCEP reanalysis II. In a first part, the datasets are inter-compared. Humidity biases are evidenced in both radiosonde observations (dry) and NCEP reanalysis (dry and wet) compared to GPS. Moisture transport and precipitation from the reanalysis and observations show a good agreement. Precipitable water shows a maximum in late summer whereas precipitation is peaking in winter and spring over Morocco. Moisture transport occurs preferentially in two layers, below and above 850 hPa. The monthly mean precipitable water variation over Morocco is controlled by the upper layer zonal and meridional moisture flux. Precipitation is rather controlled by the lower layer moisture flux and the upper layer meridional flux. The GPS tropospheric gradients show also a consistent seasonal evolution, which is explained by gradients both in the thickness of the troposphere and in the precipitable water vapor. Tropospheric gradients are correlated with moisture fluxes, mostly in the upper layer, and may therefore provide valuable information for meteorology and climatology.

Description

Keywords

PRECIPITABLE WATER VAPOR, GLOBAL POSITIONING SYSTEM, ZENITH TOTAL DELAY, RADIOSONDES, NCEP, MOROCCO, SEASONAL VARIATIONS, PRECIPITATION

Citation

Koulali, A., Ouazar, D., Bock, O., & Fadil, A. (2012). Study of seasonal-scale atmospheric water cycle with ground-based GPS receivers, radiosondes and NWP models over Morocco. Atmospheric Research, 104-105, 273-291.doi:10.1016/j.atmosres.2011.11.002

DOI