Spatial and Temporal Variabilty of Precipitable Water Vapor from Era-Interim over Ethiopia During 2006-2012
No Thumbnail Available
Date
2013-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Signals from the Global Positioning System (GPS) are used to retrieve the
integrated amount of water vapor along the path between a transmitting satellite
and a receiving station. This integrated quantity is called slant water vapor (SW).
Measurements of SW allow for an improved assessment of the spatial distribution
of water vapor within the atmosphere. A study of 7 years (2006-2012) Precip-
itable water vapour contents (PWVCs) from European Centre for Medium-Range
Weather Forecasts (ECMWF) data have been used over the region (3 150N,
32 480E) of Ethiopia for a particular time interval of 00:00, 06:00, 12:00 and
18:00 UTC has been carried out. The time series of PWV and its deviation from
annual mean also brought out for all the years. Both dry and moist years in both
monsoon and post monsoon season shows almost increasing trend of PWV for all
the years. There exists a well de ned seasonal variation in precipitable water vapor
content with maximum during monsoon months (June-September) and minimum
during the month of March. Variability in PWVC is higher during post-monsoon
and winter months (October to February) and smaller during pre-monsoon and
monsoon months (March to September). It indicates that local modi cation of
weather systems either sea bridge or entrainment of dry or moist air also play an
important role in rainfall
Description
Keywords
Era-Interim over Ethiopia During 2006-2012