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Vertical Moist Thermodynamic Structure and Spatial-Temporal Evolution of the MJO in AIRS ObservationsThe atmospheric moisture and temperature profiles from the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit on the NASA Aqua mission, in combination with the precipitation from the Tropical Rainfall Measuring Mission (TRMM), are employed to study the vertical moist thermodynamic structure and spatial-temporal evolution of the Madden-Julian oscillation (MJO). The AIRS data indicate that, in the Indian Ocean and western Pacific, the temperature anomaly exhibits a trimodal vertical structure: a warm (cold) anomaly in the free troposphere (800-250 hPa) and a cold (warm) anomaly near the tropopause (above 250 hPa) and in the lower troposphere (below 800 hPa) associated with enhanced (suppressed) convection. The AIRS moisture anomaly also shows markedly different vertical structures as a function of longitude and the strength of convection anomaly. Most significantly, the AIRS data demonstrate that, over the Indian Ocean and western Pacific, the enhanced (suppressed) convection is generally preceded in both time and space by a low-level warm and moist (cold and dry) anomaly and followed by a low-level cold and dry (warm and moist) anomaly. The MJO vertical moist thermodynamic structure from the AIRS data is in general agreement, particularly in the free troposphere, with previous studies based on global reanalysis and limited radiosonde data. However, major differences in the lower-troposphere moisture and temperature structure between the AIRS observations and the NCEP reanalysis are found over the Indian and Pacific Oceans, where there are very few conventional data to constrain the reanalysis. Specifically, the anomalous lower-troposphere temperature structure is much less well defined in NCEP than in AIRS for the western Pacific, and even has the opposite sign anomalies compared to AIRS relative to the wet/dry phase of the MJO in the Indian Ocean. Moreover, there are well-defined eastward-tilting variations of moisture with height in AIRS over the central and eastern Pacific that are less well defined, and in some cases absent, in NCEP. In addition, the correlation between MJO-related mid-tropospheric water vapor anomalies and TRMM precipitation anomalies is considerably more robust in AIRS than in NCEP, especially over the Indian Ocean. Overall, the AIRS results are quite consistent with those predicted by the frictional Kelvin-Rossby wave/conditional instability of the second kind (CISK) theory for the MJO.
Document ID
20070032889
Acquisition Source
Jet Propulsion Laboratory
Document Type
Reprint (Version printed in journal)
Authors
Tian, Baijun
(California Inst. of Tech. Pasadena, CA, United States)
Waliser, Duane E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
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)
Yung, Yuk L.
(California Inst. of Tech. Pasadena, CA, United States)
Wang, Bin
(Hawaii Univ. Honolulu, HI, United States)
Date Acquired
August 23, 2013
Publication Date
October 1, 2006
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 63
Issue: 10
Subject Category
Meteorology And Climatology
Distribution Limits
Public
Copyright
Other
Keywords
troposhere
temperature
water vapor
climate

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