Global Surface and Atmospheric Radiative Fluxes

A new version of the upwelling and downwelling, shortwave and longwave radiative fluxes has been calculated at the top of the atmosphere, in the atmosphere, and at the surface using a complete radiative transfer model from the GISS GCM (revised) with improved observations of the physical properties of the surface, atmosphere, and clouds based on the International Satellite Cloud Climatology Project (ISCCP) data sets. Results (called the FD datasets) are obtained every three hours over the whole globe on a 280 km equal-area (EQ) global grid covering the time period July 1983 through December 2007. The FD dataset (124 Mbytes per data month) contains these fluxes for full, clear and overcast (cloudy) sky, along with the input data used in the flux calculations. The ISCCP FD TOA and FD SRF data sets are now available via anonymous ftp. Note that a new version 0.10 for the year 2004 has been placed on 2007 September 18 in the anonymous ftp site for the 5 FD data sets. See the ISCCP data product description page for more details. Additionally, the complete FD dataset is also available upon request. Contact Dr. William B. Rossow or Dr. Yuanchong Zhang for further information (see announcement).

FD On-line Data and Images

Documentation and Publications

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New ISCCP Global Radiative Flux Data Products

Yuanchong Zhang1 and William B. Rossow2
Department of Applied Physics and Applied Mathematics, Columbia University1
NASA Goddard Institute for Space Studies (GISS)2

The International Satellite Cloud Climatology Project (ISCCP) has produced a new 25-year (1983-2007) global radiative flux data product called ISCCP FD. The figures below illustrate a unique aspect of this product, which provides physically consistent surface and top-of-atmosphere (TOA) radiative fluxes by showing the global monthly mean net shortwave (SW) and net longwave (LW) anomalies at the surface, in the atmosphere and at the TOA over the whole time period. Notable features are: (1) a decrease of the net SW at the surface and TOA, as well as in the atmosphere produced by the Mt. Pinatubo volcanic aerosols in 1991-92; (2) an overall increase of the net SW at TOA and the surface, but not in the atmosphere, from the 1980s to 1990s associated with a decrease in low-latitude cloud cover; (3) three (possibly four) decreases in net LW at the surface and increases in the atmosphere, but not at TOA; and (4) a small decrease of net LW at TOA and in the atmosphere and a larger increase of net LW at the surface occurring in the late 1990s. Another unique feature of the flux profile product is that it provides, for the first time, a comprehensive determination of the synoptic scale variations of the vertical profiles of radiative diabatic heating, albeit with crude vertical resolution, but sufficient to represent radiative heating in the lower, middle or upper troposphere and the stratosphere.

The product was created by employing the NASA GISS climate Global Circulation Model (GCM) radiative transfer code and a collection of global data sets describing the properties of the clouds and the surface every 3 hours (ISCCP); daily atmospheric profiles of temperature and humidity (National Oceanic and Atmospheric Administration Television InfraRed Observation Satellites (TIROS) Operational Vertical Sounder); daily ozone abundances (Total Ozone Mapping Spectrometer); a climatology of cloud vertical layer distributions from rawinsonde humidity profiles (Wang et al., 2000); a climatology of cloud particle sizes (Han et al., 1994, 1999); a climatology of stratospheric aerosol and water vapor (Stratospheric Aerosol and Gas Experiment-II); a climatology of the diurnal variations of near-surface air temperature (surface weather observations and National Centers for Environmental Protection [NCEP-1] re-analysis); a climatology of tropospheric aerosols (NASA GISS climate model); and the spectral dependence of land surface albedo and emissivity by land-cover type (NASA GISS climate model). The results include the all-sky and clear-sky, upwelling and downwelling, total shortwave (SW = 0.4 - 5 m wavelength) and total longwave (LW = 5 - 200 m wavelength) radiative fluxes at five levels: surface, 680 mb, 440 mb, 100 mb and top-of-atmosphere. All of these results are reported with a resolution of 3 hours and 280 km (equal-area map equivalent to 2.5 degrees latitude-longitude at the equator) in four data products: (1) TOA RadFlux, (2) Surface Radiative Fluxes (SRF RadFlux), (3) Radiative flux profiles including TOA and SRF fluxes (RadFlux Profiles), (4) the complete input data collection (RadFlux Inputs) and (5) monthly-mean flux profile (i.e., monthly average from the third product). The first three products include a summary of the most relevant input physical parameters, whereas the fourth product contains the exact inputs used to calculate all the fluxes.

Several papers have been published to describe the features of the radiative transfer model and the input data sets and to provide results of comparisons with other more direct determinations of the surface and top-of-atmosphere radiative fluxes (Zhang et al., 2004). More information can be found in this page or by contacting the authors (yzhang@giss.nasa.gov or wbrossow@ccny.cuny.edu). These data products are available from the authors in a preliminary format.

Note: In December 2002, the GEWEX Surface Radiation Budget (SRB) Project will release a 1x1 degree, 3-hourly, SW and LW surface radiative flux data set covering the period 1983-1995 (see map grid information page). These fluxes are also based on the ISCCP cloud products, but use different sources of information about the atmosphere and surface. These data will be available through the Atmospheric Sciences Data Center at NASA Langley Research Center at http://eosweb.larc.nasa.gov/PRODOCS/srb/table_srb.html.

References

Han, Q.-Y., W.B. Rossow, and A.A. Lacis, 1994. Near-global survey of effective cloud droplet radii in liquid water clouds using ISCCP data. J. Climate, 7, 465-497. (Read abstract.)

Han, Q., W.B. Rossow, J. Chou, K-S. Kuo, and R.M. Welch, 1999. The effects of aspect ratio and surface roughness on satellite retrievals of ice-cloud properties. J. Quant. Spectrosc. Radiat. Trans., 63, 559-583. (Read abstract.)

Wang, J., W.B. Rossow, and Y-C Zhang, 2000. Cloud vertical structure and its variations from a 20-year global rawinsonde data set. J. Climate, 13, 3041-3056. (Read abstract.)

Zhang, Y-C., W.B. Rossow, A.A. Lacis, V. Oinas, and M.I. Mishchenko, 2004. 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. J. Geophys. Res., 109, (27 pp). Download PDF document and Auxiliary Material files (MS Word format).

Rossow, W.B., Y-C. Zhang and J-H. Wang (2005), A statistical model of cloud vertical structure based on reconciling cloud layer amounts inferred from satellites and radiosonde humidity profiles. J. Climate, 18, 3587-3605. Download PDF document

Zhang, Y., W. B. Rossow, and P. W. Stackhouse Jr. (2006), Comparison of different global information sources used in surface radiative flux calculation: Radiative properties of the near-surface atmosphere, J. Geophys. Res., 111, D13106, doi:10.1029/2005JD006873. Download PDF document

Zhang, Y., W. B. Rossow, and P. W. Stackhouse, Jr. (2007), Comparison of different global information sources used in surface radiative flux calculation: Radiative properties of the surface, J. Geophys. Res., 112, D01102, doi:10.1029/2005JD007008. Download PDF document

Zhang, Y., W. B. Rossow, P. Stackhouse, Jr., A. Romanou, and B. A. Wielicki (2007), Decadal variations of global energy and ocean heat budget and meridional energy transports inferred from recent global data sets,J. Geophys. Res., 112, D22101, doi:10.1029/2007JD008435. Download PDF document


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