A comparison of satellite water vapor observations with model simulations
- NOAA/ERL Climate Diagnostic Center, Boulder, CO (United States)
- CIRES Univ. of Colorado, Boulder, CO (United States)
This paper compares observations of precipitable water (PW) and upper tropospheric humidity (UTH) with Atmospheric Model Intercomparison Project (AMIP) simulations. PW observational data was from a scanning multichannel microwave radiometer (SSMR); the mean observed PW for the 6-year coincident period was compared with AMIP simulation. Upper tropospheric relative humidity observational data was obtained from high resolution infrared radiometer instruments on NOAA satellites. Direct comparisons of observed UTH data are made with AMIP relative humidity. The model means and variability over the oceans compare well with values from SMMR observations. The mean annual cycle of PW from AMIP compares well with SMMR data, although SMMR values are consistently higher in the tropics. Interannual anomaly time series correlations between SMMR and AMIP PW values show a high regional dependence. In the subtropics, about one third of the AMIP models show highly significant interannual anomaly correlations, about one third show significant correlations, and about one third are not significantly correlated. In the tropics, almost all of the AMIP models are highly significantly correlated with the SMMR interannual PW anomalies; this is attributed to similar model responses during the extreme El Nino event of 1982-83. All models show significantly higher relative humidity at all levels; this may be due to tuning against radiosonde climatologies of upper tropospheric humidity climatologies that contain known large systematic biases. Variations in 10-year mean 300 millibar relative humidity between models was shown to be significantly different. Overall, the models are doing only an adequate job in simulation of PW and its variability, and are doing a completely inadequate job of simulating UTH and its variability. Inadequate simulation of UTH translates into large errors in simulation of the outgoing longwave radiation. 12 refs., 5 figs., 1 tab.
- OSTI ID:
- 535493
- Report Number(s):
- CONF-970207-; TRN: 97:005076-0025
- Resource Relation:
- Conference: 77. annual meeting of the American Meteorological Society, Long Beach, CA (United States), 2-7 Feb 1997; Other Information: PBD: 1997; Related Information: Is Part Of Eighth symposium on global change studies; PB: 402 p.
- Country of Publication:
- United States
- Language:
- English
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