Determination of top‐of‐atmosphere longwave radiative fluxes: A comparison between two approaches using ScaRaB data

Chen, Ting; Rossow, William B.

doi:10.1029/2001jd000914

Cited by 5 publications

(10 citation statements)

References 46 publications

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“…Compared with FC versus ERBE, the global mean albedo bias has also decreased by more than a half: from 3.3% to 1.4% for full sky and from 1.2% to 0.5% for clear sky. For LW fluxes, the major improvement is in the clear‐sky component: The bias is now reduced to −5.6 Wm −2 from −9.2 Wm −2 , while the bias for full‐sky LW is increased slightly from −1.1 to −2.2 Wm −2 , associated with the overestimate of the height of the thinnest cirrus clouds in the ISCCP results [ Chen and Rossow , 2002]. The LW RMS differences and correlation coefficients are about the same, but the slope/intercepts of the scatterplots are significantly better, indicating a decrease of regional biases.…”

Section: Evaluation Of the New Resultsmentioning

confidence: 99%

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Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data

2004

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[1] We continue reconstructing Earth's radiation budget from global observations in as much detail as possible to allow diagnosis of the effects of cloud (and surface and other atmospheric constituents) variations on it. This new study was undertaken to reduce the most noticeable systematic errors in our previous results (flux data set calculated mainly using International Satellite Cloud Climatology Project-C1 input data (ISCCP-FC)) by exploiting the availability of a more advanced NASA Goddard Institute for Space Studies (GISS) radiative transfer model and improved ISCCP cloud climatology and ancillary data sets. The most important changes are the introduction of a better treatment of ice clouds, revision of the aerosol climatology, accounting for diurnal variations of surface skin/air temperatures and the cloud-radiative effects on them, revision of the water vapor profiles used, and refinement of the land surface albedos and emissivities. We also extend our previous flux results, limited to the top of atmosphere (TOA) and surface (SRF), to also include three levels within the atmosphere, forming one integrated vertical atmospheric flux profile from SRF to TOA, inclusive, by combining a new climatology of cloud vertical structure with the ISCCP cloud product. Using the new radiative transfer model and new input data sets, we have produced an 18-year at 3-hour time steps, global at 280-km intervals, radiative flux profile data set (called ISCCP-FD) that provides full-and clear-sky, shortwave and longwave, upwelling and downwelling fluxes at five levels (SRF, 680 mbar, 440 mbar, 100 mbar, and TOA). Evaluation is still only possible for TOA and SRF fluxes: Comparisons of monthly, regional mean values from FD with Earth Radiation Budget Experiment, Clouds and the Earth's Radiant Energy System and Baseline Surface Radiation Network values suggest that we have been able to reduce the overall uncertainties from 10-15 to 5-10 W/m 2 at TOA and from 20-25 to 10-15 W/m 2 at SRF. Annual mean pressure-latitude cross sections of the cloud effects on atmospheric net radiative fluxes show that clouds shift the longwave cooling downward in the Intertropical Convergence Zone, acting to stabilize the tropical atmosphere while increasing the horizontal heating gradient forcing the Hadley circulation, and shift the longwave cooling upward in the midlatitude storm zones, acting to destabilize the baroclinic zones while decreasing the horizontal heating gradient there.

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Section: Evaluation Of the New Resultsmentioning

confidence: 99%

“…For L ↑ t there are still 4–8 Wm −2 high biases in the ITCZ [cf. Chen and Rossow , 2002]. However, the accuracy of the ERBE ADMs for specific cloud types, especially ones that are very different from global mean conditions, is uncertain, so further evaluation of cloud‐type dependence must await the improved CERES ADMs.…”

Section: Summary and Discussionmentioning

confidence: 99%

Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data

2004

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“…Tests of the radiative effects by Chen and Rossow (2002) show that this does not affect the results by more than 1-2 W m −2 . (2) ISCCP cloud detections are less reliable in the polar regions, where it appears that the ISCCP cloud amounts are underestimated, particularly in summertime.…”

Section: Cloudsmentioning

confidence: 90%

“…(3) Multi-layered clouds are misidentified as middle-level clouds when the uppermost layer is optically thin, which appears to happen about 15-25% of the time. This causes some bias in the terrestrial radiation fluxes (Chen and Rossow, 2002).…”

Section: Cloudsmentioning

confidence: 99%

Cloud effects on the radiation budget based on ISCCP data (1991 to 1995)

Raschke

Ohmura

Rossow

et al. 2005

Intl Journal of Climatology

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Consistent and validated data sets of satellite-borne radiances and of a large variety of products describing the characteristics of terrestrial cloud and radiation fields have been produced within the International Satellite Cloud Climatology Project (ISCCP) covering the years 1983 through to 2003. A subset (annual and seasonal averages of the 5 year period 1991 to 1995) is used in this paper to discuss in greater detail the effect of clouds on the radiation fields at the upper and lower boundary of the atmosphere and in particular on the loss and gain (vertical divergence) of radiant energy by the atmosphere itself. Although this subset covers the effects of the Pinatubo eruption (June 1991) and of the strong El Niño event in 1992-93, which indeed caused 'anomalies in the average aerosol and cloud fields in the tropics and subtropics'. However, our regional averages of the radiation budget at the top of the atmosphere and at ground over a period of 5 years should be within 2-5 W m −2 of longer term averages.We find very interesting spatial patterns in the global distributions of all quantities, which can be explained in part by various cloud field characteristics and by the continental surface characteristics. Most are known from similar studies with radiation budget measurements. Possibly for the first time, we show global fields of the vertical flux divergence of solar and terrestrial radiation within the atmosphere and of the effects of clouds. Both polar regions, various portions of China and the areas of persistent subtropical maritime stratocumulus fields over the Pacific and Atlantic Oceans and of cloud fields associated with the intertropical convergence zone (ITCZ) offer specific features for further analyses.This ISCCP data set seems to underestimate the absorption of solar radiation in the tropical and subtropical atmosphere by about 10 to 20 W m −2 . There is a disagreement of about 30 W m −2 in global averages of the gain and loss of solar and terrestrial radiation in the atmosphere between this and two other independent data sets, which needs thorough investigation, since such data are required to validate the radiation budgets within circulation and climate models and for other climate studies. Such an assessment of radiation budget data is now under way within the auspices of the World Climate Research Programme.

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“…A number of studies for estimating radiation budgets have been published since the 1990s (Rossow and Lacis, 1990;Kyle et al, 1990;Stephens and Greenwald, 1991;Darnell et al, 1992;Hartmann, 1993;Kiehl et al, 1994;Rossow and Zhang, 1995;Whitlock et al, 1995;Del Genio et al, 1996;Chen and Roeckner, 1996;Fowler and Randall, 1996). More recent studies are those by Li et al (1997), Wild et al (1998a,b), Garrat et al (1998), Yu et al (1999), Yang et al (1999), Hatzianastassiou et al (1999Hatzianastassiou et al ( , 2001), Vardavas (1999a,b, 2001a,b), Gupta et al (1999), Allan (2000), and Chen and Rossow (2002). However, all of these studies estimate either SW or LW radiative fluxes separately, or they compute radiation budgets at either TOA or at the Earth's surface only, or they provide radiation budgets for time periods of up to 8 years.…”

Section: Introductionmentioning

confidence: 99%

Ten year radiation budget of the Earth: 1984–93

Hatzianastassiou

Matsoukas

Hatzidimitriou

et al. 2004

Intl Journal of Climatology

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A 10 year climatology is given of the global distributions of net shortwave (SW), net longwave (LW) and net all-wave radiation budget at both top-of-atmosphere (TOA) and at the Earth's surface, on a mean monthly basis, computed with a radiative transfer model with input data for key atmospheric and surface parameters. The model input data were taken from complete and comprehensive global climatological data sets, such as the International Satellite Cloud Climatology Project, the National Centers for Environmental Prediction and National Center for Atmospheric Research Global Reanalysis or the TIROS Operational Vertical Sounder, among others. Seasonal and latitudinal variations and mean annual and mean hemispherical and global averages are given, based on model results computed for each month of the period from January 1984 to December 1993. At TOA, the net incoming SW radiation has larger latitudinal variation and range of values (0-400 W m −2 ) than the outgoing LW radiation (100-350 W m −2 ). At the surface, the net downward SW radiation has similar features to that at TOA, but with smaller magnitudes. The net upward LW radiation is quite different than at TOA, with a smaller seasonal and geographical variability than the surface net SW radiation. The global system of Earth-atmosphere is found to be net radiatively heated at TOA by 3 W m −2 ; the Earth's surface is net heated by 98 W m −2 , mainly due to solar absorption equal to 147 W m −2 , a value in agreement with surface-based measurements. At TOA, there is a radiative energy surplus between 40°S and 30°N and a radiative loss poleward; however, at the surface the surplus regions extend from 70°S to 70°N. Globally, the atmosphere is found to absorb 27% of the incoming solar radiation at TOA, while it emits 79% of the outgoing terrestrial radiation.

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Determination of top‐of‐atmosphere longwave radiative fluxes: A comparison between two approaches using ScaRaB data

Cited by 5 publications

References 46 publications

Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data

Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data

Cloud effects on the radiation budget based on ISCCP data (1991 to 1995)

Ten year radiation budget of the Earth: 1984–93

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