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Space-Time Variations in Water Vapor as Observed by the UARS Microwave Limb SounderWater vapor in the upper troposphere has a significant impact on the climate system. Difficulties in making accurate global measurements have led to uncertainty in understanding water vapor's coupling to the hydrologic cycle in the lower troposphere and its role in radiative energy balance. The Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite is able to retrieve water vapor concentration in the upper troposphere with good sensitivity and nearly global coverage. An analysis of these preliminary retrievals based on 3 years of observations shows the water vapor distribution to be similar to that measured by other techniques and to model results. The primary MLS water vapor measurements were made in the stratosphere, where this species acts as a conserved tracer under certain conditions. As is the case for the upper troposphere, most of the stratospheric discussion focuses on the time evolution of the zonal mean and zonally varying water vapor. Stratospheric results span a 19-month period and tropospheric results a 36-month period, both beginning in October of 1991. Comparisons with stratospheric model calculations show general agreement, with some differences in the amplitude and phase of long-term variations. At certain times and places, the evolution of water vapor distributions in the lower stratosphere suggests the presence of meridional transport.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Elson, Lee S. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Read, William G. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Waters, Joe W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Mote, Philip W. (Edinburgh Univ. United Kingdom)
Kinnersley, Jonathan S. (Edinburgh Univ. United Kingdom)
Harwood, Robert S. (Edinburgh Univ. United Kingdom)
Date Acquired
August 19, 2013
Publication Date
April 20, 1996
Publication Information
Publication: Journal of Geophysical Research
Volume: 101
Issue: D4
ISSN: 0148-0227
Subject Category
Report/Patent Number
Distribution Limits