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Biases in Total Precipitable Water Vapor Climatologies from Atmospheric Infrared Sounder and Advanced Microwave Scanning RadiometerWe examine differences in total precipitable water vapor (PWV) from the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Scanning Radiometer (AMSR-E) experiments sharing the Aqua spacecraft platform. Both systems provide estimates of PWV over water surfaces. We compare AIRS and AMSR-E PWV to constrain AIRS retrieval uncertainties as functions of AIRS retrieved infrared cloud fraction. PWV differences between the two instruments vary only weakly with infrared cloud fraction up to about 70%. Maps of AIRS-AMSR-E PWV differences vary with location and season. Observational biases, when both instruments observe identical scenes, are generally less than 5%. Exceptions are in cold air outbreaks where AIRS is biased moist by 10-20% or 10-60% (depending on retrieval processing) and at high latitudes in winter where AIRS is dry by 5-10%. Sampling biases, from different sampling characteristics of AIRS and AMSR-E, vary in sign and magnitude. AIRS sampling is dry by up to 30% in most high-latitude regions but moist by 5-15% in subtropical stratus cloud belts. Over the northwest Pacific, AIRS samples conditions more moist than AMSR-E by a much as 60%. We hypothesize that both wet and dry sampling biases are due to the effects of clouds on the AIRS retrieval methodology. The sign and magnitude of these biases depend upon the types of cloud present and on the relationship between clouds and PWV. These results for PWV imply that climatologies of height-resolved water vapor from AIRS must take into consideration local meteorological processes affecting AIRS sampling.
Document ID
20070032964
Acquisition Source
Jet Propulsion Laboratory
Document Type
Reprint (Version printed in journal)
Authors
Fetzer, Eric J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Lambrigtsen, Bjorn H.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Eldering, Annmarie
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Aumann, Hartmut H.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Chahine, Moustafa T.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 23, 2013
Publication Date
April 26, 2006
Publication Information
Publication: Journal Of Geophysical Research
Publisher: American Geophysical Union
Volume: 111
ISSN: 0148-0227
Subject Category
Meteorology And Climatology
Distribution Limits
Public
Copyright
Other
Keywords
Atmospheric Infrared Sounder (AIRS)
remote sounding
clouds
validation
water vapor

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