vations began on 24 February 1994 and continued
(with some interruptions) until 6 March 1995 when the
instrument failed. The instrument, described in section
2 below (cf. also Monge et al. 1991; Kandel et al.
1994a), measured reflected and emitted radiances in
four channels (visible, solar, total, infrared window);
these data have been processed to yield broadband
shortwave (SW) and longwave (LW) fluxes, for all-
sky and clear-sky scenes, on the same spatial and tem-
poral scales as the ERBE [National Aeronautics and
Space Administrations (NASA) Earth Radiation Bud-
get Experiment] products (Barkstrom et al. 1989).
Following examination by participating project mem-
bers and the International ScaRaB Scientific Working
Group (ISSWG; see Table 1), a set of ScaRaB-1 prod-
ucts has been judged to be sufficiently validated to
be made available to the broader scientific community
for further study and scientific use (available upon
request from scarab@cst.cnes.fr). Here, following a
The ScaRaB Earth Radiation
Budget Dataset
R. Kandel,* M. Viollier,* P. Raberanto,* J. Ph. Duvel,* L. A. Pakhomov,
+
V. A. Golovko,
+
A. P. Trishchenko,
#,&
J. Mueller,
@
E. Raschke,
@
R. Stuhlmann,
@
and the International ScaRaB Scientific Working Group (ISSWG)
ABSTRACT
Following an overview of the scientific objectives and organization of the FrenchRussianGerman Scanner for
Radiation Budget (ScaRaB) project, brief descriptions of the instrument, its ground calibration, and in-flight operating
and calibration procedures are given. During the year (24 February 19946 March 1995) of ScaRaB Flight Model 1
operation on board Meteor-3/7, radiometer performance was generally good and well understood. Accuracy of the radi-
ances is estimated to be better than 1% in the longwave and 2% in the shortwave domains. Data processing procedures
are described and shown to be compatible with those used for the National Aeronautics and Space Administrations
(NASA) Earth Radiation Budget Experiment (ERBE) scanner data, even though time sampling properties of the Me-
teor-3 orbit differ considerably from the ERBE system orbits. The resulting monthly mean earth radiation budget distri-
butions exhibit no global bias when compared to ERBE results, but they do reveal interesting strong regional differences.
The ERBE-like scientific data products are now available to the general scientific research community. Prospects for
combining data from ScaRaB Flight Model 2 (to fly on board Ressurs-1 beginning in spring 1998) with data from the
NASA Clouds and the Earths Radiant Energy System (CERES) instrument on board the Tropical Rainfall Measure-
ment Mission (TRMM) are briefly discussed.
*Laboratoire de Météorologie Dynamique, Centre National de la
Recherche Scientifique, Palaiseau, France.
+
Scientific Research Center for Exploration of Natural Resources
Dolgoprudny, Russia.
#
Research Institute for Hydrometeorological Information,
Obninsk, Russia.
@
Institute for Atmospheric Physics, GKSS Research Center,
Geesthacht, Germany.
&
Current affiliation: Canada Centre for Remote Sensing, Ottawa,
Ontario, Canada.
Corresponding author address: Dr. Robert Kandel, Laboratoire
de Météorologie Dynamique du CNRS, Ecole Polytechnique, F-
91128 Palaiseau, Cedex, France.
E-mail: Kandel@lmd.polytechnique.fr
In final form 5 January 1998.
©1998 American Meteorological Society 766
Vol. 79, No. 5, May 1998
CNRSLaboratoire de Météorologie Dynamique (BRC+instrument
teams), Ecole Polytechnique, Palaiseau, France
Scientific Research Center for the Study of Natural Resources,
Moscow, Russia
Research Inst. on Hydrometeorological Information, Obninsk,
Russia
Inst. for Atmospheric Physics, GKSS Research Centre, Geesthacht,
Germany
CNESCentre Spatial de Toulouse, France
ISSWG partners
California Space Inst., University of California, La Jolla, California
Canada Centre for Remote Sensing, Ottawa, Canada
CNRSLaboratoire de Météorologie Dynamique (ARA team),
Ecole Polytechnique, Palaiseau, France
CNRSLaboratoire de Météorologie Dynamique, BRC and MDC
teams, Palaiseau and Paris, France
CNRSLaboratoire dOptique Atmosphérique, Univ. Sci. Techn. de
Lille, France
Hadley Centre for Climate Prediction and Research, Meteorological
Office, Bracknell, United Kingdom
Inst. of Atmos. Sci., South Dakota School of Mines and
Technology, Rapid City, South Dakota
KMIIRM (Royal Meteorological Institute), Brussels, Belgium
NASA/Goddard Institute for Space Studies, New York, New York
NASA/Langley Research Center, Hampton, Virginia
Saratov State University, Saratov, Russia
Satellite Research Laboratory, Hungarian Met. Serv., Budapest,
Hungary
Voeikov Main Geophysical Observatory, Saint Petersburg,
Tsvetkov, Russia
R. Kandel, M. Capderou, J. Ph. Duvel, P. Raberanto,
F. Raison, F. Sirou, C. Stubenrauch, M. Viollier
L. A. Pakhomov, V. A. Golovko, A. B. Uspensky
R. G. Reitenbach, A. N. Trotsenko (Kurchatov Inst.,
Moscow), A. P. Trishchenko (now at CCRS, Ottawa,
Canada)
R. Stuhlmann, E. Raschke, J. Mueller, H. Leighton
(McGill University, Montreal)
J. Roussel, Th. Trémas, H. Marquier, J.-F. Fronton
W. Collins (now at NCAR, Boulder, Colorado)
A. P. Trishchenko, Z. Li
F. Cheruy, N. A. Scott
J.-P. Duvel, S. Bony, M. Capderou, R. Kandel,
H. Le Treut, C. Stubenrauch, M. Viollier
F. Parol, J. C. Buriez, Y. Fouquart, M. Vesperini
A. Slingo, J. A. Pamment, M. J. Webb, J. E. Harries
[Imperial Coll. London (ICL)], A. Sinha (ICL), K. P.
Shine (University of Reading)
S. A. Christopher, R. M. Welch (now at University of
Alabama in Huntsville, Huntsville, Mississippi)
D. Crommelynck, J. Cornelis (VUB), P. Boekaerts
(VUB), M. Acheroy (ERM)
A. A. Lacis, B. E. Carlson, W. B. Rossow
G. L. Smith (Virginia Polytechnic Inst.), E. F.
Harrison, R. B. Lee III, T. P. Charlock, P. Minnis
Yu. A. Sklyarov, D. I. Trubetskov
G. Major, I. Csiszar, M. Putsay, A. Rimoczi-Paal,
A. Merza
G. G. Shchukin, O. M. Pokrovsky, A. V. Tsvetkov
T
ABLE
1. The International ScaRaB Scientific Working Group (ISSWG).
Participating institution/
original project partners
Principal investigator, co-PIs, co-Is 767
Bulletin of the American Meteorological Society
brief review of the scientific problems to which such
data are relevant, we present an overview of the 1-yr
ScaRaB-1 data product set. In particular, we describe
the instrument (section 2) and its performance and
calibration (section 3) so that prospective users will
be aware of the potential problems in the data. In sec-
tion 4 we evaluate to what extent the ScaRaB process-
ing from pixel radiances to monthly regional mean
fluxes is consistent with procedures used in ERBE, and
the uncertainties that affect different data products. In
section 5 we survey the salient features of the ScaRaB-
1 results, comparing them to the ERBE record. In the
final section, we consider prospects for continuing and
improved radiation budget measurements from
ScaRaB-2, CERES (Clouds and the Earths Radiant
Energy System), and other projected missions.
b. Earth radiation budget observations for climate
research
The planetary radiation budget has always been a
key parameter of interest for climate research, as a
measure of the energy exchanges between the planet
Earth and space and for the forcing or atmospheric and
ocean circulation systems. Early estimates (cf. Hunt
et al. 1986) were based on conventional climatologi-
cal data and also on the earthshine on the moon. Later
analyses used data from the first and second genera-
tions of meteorological satellites and from the NASA
Nimbus missions (cf., e.g., Raschke et al. 1973;
Stephens et al. 1981; Jacobowitz et al. 1984; House
et al. 1986). All energy exchange of significance between
the earthatmosphere system and its cosmic environ-
ment is radiative (cf., e.g., Kandel 1990). The system
absorbs part of the incoming solar SW radiation flux
and reemits this energy flux to space in degraded LW
form with a spectrum characteristic of temperatures in
the 200300-K range. Reflected solar SW radiation
flux, with a spectrum extending roughly from 0.2 to
5
µ
m, ranges from zero to 1000 W m 2
locally and in-
stantaneously. The earthatmosphere system emits
LW thermal radiation over wavelengths mostly greater
than 3.3
µ
m; outgoing LW flux ranges from 120 to
450 W m 2
with a global annual mean value of
238 W m 2
. Reflected SW and emitted LW spectra are
fairly distinct, although there is overlap during day-
time at wavelengths between 3.3 and 5
µ
m, where ra-
diative flux density is relatively low for both spectra.
The distribution of top of atmosphere (TOA) net
radiation (radiation balance, equal to absorbed SW
minus emitted LW fluxes) defines the energy sources/
sinks that drive the general circulation of the atmo-
sphere and oceans but is at the same time a conse-
quence of the general circulation. The absorbed (inci-
dent reflected) solar SW radiation gives the (mostly)
externally imposed radiative forcing of the system.
The annual cycle of the global mean TOA net radia-
tion has a reasonably well-determined peak-to-peak
amplitude of approximately 15 W m 2
, with maximum
positive values occurring in late Southern Hemisphere
summer. The nonzero values (a few watts per square
meter) of the annual average global mean TOA net
radiation found from ERBE and ScaRaB data are an
indication of observational uncertainty rather than of
global radiative imbalance. The geographic distribu-
tion of the LW flux emitted to space (also called out-
going longwave radiation) provides useful information
on the overall state of the surfaceatmosphere column.
Important progress has been made in es