The climatological minimum in tropical outgoing infrared radiation: Contributions of humidity and clouds

Warren, Stephen G.; Thompson, Starley L.

doi:10.1002/qj.49710945908

Cited by 10 publications

(2 citation statements)

References 29 publications

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“…The secondary minimum near the equator is displaced toward the summer hemisphere during the solstitial seasons. This minimum is associated partly with humidity variations [Warren and Thompson, 1983] but primarily with the band of tall convective cloud near the equator which is often referred to as the intertropical convergence zone. As we shall see later, however, this cloudiness does not form a zonally uniform band but tends to be most prevalent at the longitudes of South America, Africa, and Indonesia.…”

Section: Latitude Zonesmentioning

confidence: 99%

Earth Radiation Budget data and climate research

Hartmann¹,

Ramanathan²,

Berroir³

et al. 1986

Reviews of Geophysics

145

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An overview is presented of the uses of top of the atmosphere radiation budget measurements in studies of climate. The net radiative energy flux at the top of the atmosphere must be balanced by local heat storage in the earth-atmosphere column or by horizontal transport in the atmosphere and ocean. Regional variations in the components of the radiation balance are significant and place important constraints on regional and global climate. If suitable time averaging is applied, regional net radiation can be used to infer horizontal transport of energy in the atmosphere and ocean. Estimates of equatorto-pole transport in the atmosphere and ocean based upon currently available top-of-atmosphere radiation budget measurements contain unacceptably large uncertainties associated with uncertainties in the radiation budget measurements themselves. Diurnal and interannual variations in regional radiation balances are large and important but have not yet been properly sampled with broadband instruments. Both have the potential for providing important insights into climate. The role of cloudiness in climate sensitivity remains one of the major uncertainties in quantitative estimates of climate changes associated with particular perturbing influences. Radiation budget data can be used to estimate the effects of actual cloudiness on the top-of-atmosphere heat balance and the dependence of these effects on location and season. The observational studies of the effect of cloudiness on the radiation balance at the top of the atmosphere that have been completed to date all suffer from one or more of three fundamental problems. These are that the parameters of the cloudiness are not accurately known, the radiation budget data are not based on measurements whose frequency response is unbiased in relation to the emissions of the sun and the earth, and the diurnal sampling of the measurements is not complete. The uncertainties associated with each of these problems are expected to be reduced as a result of analyses based on data from the Earth Radiation Budget Experiment. In order that quantitative estimates of climate change be as accurate as possible the general circulation models (GCMs) which produce these forecasts must be critically evaluated with observed data. Many of the most important mechanisms for perturbing climate (e.g., CO 2, volcanic aerosols, surface albedo changes) and many of the most important feedback processes (e.g., relative humidity feedback, cloud feedback, ice-albedo feedback) directly involve the radiation balance at the top of the atmosphere and its relation to surface climate. Since the radiation balance at the top of the atmosphere can, in principle, be measured very accurately from space, it is natural that the simulation of top-of-atmosphere energy fluxes by GCMs should be carefully validated against observations. Because of the complexities introduced by clouds, a complete validation of the radiation budget of a GCM is a long and difficult task. A strategy is suggested here in which the clear-sky fluxes ...

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Section: Latitude Zonesmentioning

confidence: 99%

Earth Radiation Budget data and climate research

Hartmann¹,

Ramanathan²,

Berroir³

et al. 1986

Reviews of Geophysics

145

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show abstract

“…Research in several areas, such as weather forecast model initialization, radiation budget studies, and photochemical modeling, has emphasized the need for a consistent global water vapor data set [Mason, 1986;Warren and Thompson, 1983;Stordal et al, 1985;Le Texier et al, 1988]. A number of spacecraft experiments which measure water vapor have been launched to shed new light on the global distribution of this important atmospheric constituent.…”

Section: Introductionmentioning

confidence: 99%

Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

Chiou¹,

McCormick²,

Mcmaster³

et al. 1993

J. Geophys. Res.

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This paper presents a comparison of the stratospheric water vapor measurements made by the satellite-borne sensors the Stratospheric Aerosol and GasExperiment II (SAGE II), the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS), and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. LIMS obtained data for 7 months between November 1978 and May 1979; ATMOS was carried on Shuttle and observed eight profiles from April 30 to May 6, 1985 at approximately 30øN and 50øS; and, SAGE II continues to make measurements since its launch in October 1984. For both 30øN and 50øS in May, the comparisons between SAGE II and ATMOS show agreement within the estimated combined uncertainty of the two experiments. Several important features identified by LIMS observations have been confirmed by SAGE II: a well-developed hygropause in the lower stratosphere at low-to mid-latitudes, a poleward latitudinal gradient, increasing water vapor mixing ratios with altitude in the tropics, and the transport of dry lower stratospheric water vapor upward and southward in May, and upward and northward in November.A detailed comparative study also indicates that the two previously suggested corrections for LIMS, a correction in tropical lower stratosphere due to a positive temperature bias and the correction above 28 km based on improved emissivities will bring LIMS measurements much closer to those of SAGE II. The only significant difference occurs at high southern latitudes in May below 18 km, where LIMS measurements are 2-3 ppmv greater. It should be noted that LIMS observations are from 16 to 50 km, ATMOS from 14 to 86 km, and SAGE II from mid-troposphere to 40 km. With multiyear coverage, SAGE II observations should be useful for studying tropospheric-stratospheric exchange, for stratospheric transport, and for preparing water vapor climatologies for the stratosphere and the upper troposphere.

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Modelling the younger dryas

Harvey

1989

Quaternary Science Reviews

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The climatological minimum in tropical outgoing infrared radiation: Contributions of humidity and clouds

Cited by 10 publications

References 29 publications

Earth Radiation Budget data and climate research

Earth Radiation Budget data and climate research

Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

Modelling the younger dryas

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