JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 97, NO. D3, PAGES 2775–2780, 1992


    A comparison of observations and model simulations of tropospheric
    water vapor

Dian J. Gaffen

NOAA Air Resource Laboratory, Silver Spring, Maryland


Tim P. Barnett

Climate Research Division, Scripps Institution of Oceanography, La
Jolla, California


      Abstract

Observations of tropospheric specific humidity from radiosondes for the
period 1973–1986 are compared with simulated specific humidity fields
from a University of Hamburg version of the European Center for
Medium-Range Weather-Forecasting General Circulation Model (GCM), forced
by observed sea surface temperatures. The mean January and July fields
are shown to be in good agreement, despite the much poorer resolution of
the radiosonde network used. Temporal and spatial variations of specific
humidity are examined through empirical orthogonal function analysis of
tropical data. The first mode of variability of the data was similar to
that of the model simulations and shows evidence of a coherent,
decadal-scale variation in tropospheric moisture content. The overall
agreement between the model and the data, while not complete, suggests
that long-term mean patterns and decadal variations in moisture, as
delineated by a sparse data network, are reasonably well simulated. More
comprehensive comparisons of tropospheric moisture data with GCM
simulations from different models are suggested. © American Geophysical
Union 1991

*Index Terms: *0365 Atmospheric Composition and Structure:
Troposphere—composition and chemistry; 3309 Meteorology and Atmospheric
Dynamics: Climatology (1620).

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Citation: Gaffen, D. J., and T. P. Barnett (1992), A comparison of
observations and model simulations of tropospheric water vapor, /J.
Geophys. Res./, 97(D3), 2775–2780.