The Clouds and the Earth s Radiant Energy Systems (CERES) project is currently producing world-class climatological data products derived from measurements taken aboard the Terra and Aqua spacecrafts (Wielicki et al., 1996). While of exceptional fidelity, these data products require a considerable amount of processing to assure quality and verify accuracy and precision. Obtaining such high quality assurance, however, means that the CERES data is typically released more than six months after the acquisition of the initial measurements. For climate studies, such delays are of little consequence, especially considering the improved quality of the released data products. There are, however, many uses for the CERES data products on a near real-time basis. These include: CERES instrument calibration and subsystem quality checks, CLOUDSAT operations, seasonal predictions, agricultural and ocean assimilations, support of field campaigns, and outreach programs such as S'Cool. The FLASHflux project was envisioned as a conduit whereby CERES data could be provided to the community within a week of the initial measurements, with the trade-off that some degree of fidelity would be exacted to gain speed. In this paper, we will report on some very encouraging initial results from the FLASHflux project in which we compared the FLASHflux instantaneous surface fluxes to the CERES surface-only flux algorithm data products

Geier, Erika B.

Gupta, Shashi K.

Kratz, David P.

McGarragh, Greg R.

Stackhouse, Paul W., Jr.

NASA Technical Reports Server

P1.10          Fast Longwave and Shortwave Radiative Flux (FLASHFlux)  
Products from CERES and MODIS Measurements 
 
Paul W. Stackhouse Jr.*1, David P. Kratz1, Greg R. McGarragh2, Shashi K. Gupta3 and Erika B. Geier1 
1NASA Langley Research Center, Hampton, VA 
2Science Applications International Corp., Hampton, VA 
3Analytical Services and Materials, Inc., Hampton, VA 
 
1.   INTRODUCTION 
 
      The Clouds and the Earth’s Radiant Energy 
Systems (CERES) project is currently producing 
world-class climatological data products derived 
from measurements taken aboard the Terra and 
Aqua spacecrafts (Wielicki et al., 1996). While of 
exceptional fidelity, these data products require 
a considerable amount of processing to assure 
quality and verify accuracy and precision. 
Obtaining such high quality assurance, however, 
means that the CERES data is typically released 
more than six months after the acquisition of the 
initial measurements. For climate studies, such 
delays are of little consequence, especially 
considering the improved quality of the released 
data products. There are, however, many uses 
for the CERES data products on a near real-time 
basis. These include: CERES instrument 
calibration and subsystem quality checks, 
CLOUDSAT operations, seasonal predictions, 
agricultural and ocean assimilations, support of 
field campaigns, and outreach programs such as 
S’Cool. The FLASHflux project was envisioned 
as a conduit whereby CERES data could be 
provided to the community within a week of the 
initial measurements, with the trade-off that 
some degree of fidelity would be exacted to gain 
speed. In this paper, we will report on some very 
encouraging initial results from the FLASHflux 
project in which we compared the FLASHflux 
instantaneous surface fluxes to the CERES 
surface-only flux algorithm data products. 
Ultimately, the FLASHflux project will produce 
global gridded flux products, initially with a 1° X 
1° resolution, using a simplified time and space 
averaging algorithm. 
 
2.   THE FLASHFLUX PROJECT 
 
      The FLASHFlux project is designed around 
a data flow structure similar to the one used by 
CERES, with some critical differences (see 
Figure 1). The process begins with the 
importation of data from NASA’s Global 
Modeling and Analysis Office (GMAO) Goddard 
Earth Observing System (GEOS) global 
assimilation meteorology version 4.0.3 (Bloom et 
al., 2005) and NCEP-SMOBA (Stratosphere 
Monitoring Ozone Blended Analysis) ozone 
products (Yang et al., 1997) to produce the 
FLASH MOA dataset. Providing information 
concerning the basic state of the Earth’s 
atmosphere, this data is crucial to a number of 
the subsequent processing systems. CERES 
and MODIS measurements are then combined 
with the FLASH MOA dataset to determine the 
cloud properties for the FLASH Clouds dataset. 
These results are then combined with estimates 
for the instrument spectral responses and gains 
and processed through sophisticated angular 
distribution models (Loeb et al., 2005) and well-
established radiative transfer methods (Gupta et 
al., 2004) to produce the FLASH Single Scanner 
Footprint (SSF) dataset.). In contrast to FLASH, 
the CERES processing must wait for the 
calculation of finely detailed versions of the 
instrument spectral response functions and gain 
coefficients. This wait contributes significantly to 
the delay in the availability of the CERES data, 
while estimating the instrument characteristics 
on past trends allows FLASH to process the 
measurements very rapidly. 
      The FLASH SSF dataset, which provides 
instantaneous surface radiances and fluxes, has 
already been used in support of activities such 
as the June, 2005 balloon flight of the FIRST 
instrument (Mlynczak et al., 2006), validation of 
the CERES spectral correction techniques, and 
the S’Cool outreach program. Current planning 
has the FLASH SSF being used in the 
operational processing of CloudSat data, as well 
as the fusion product of Aqua, CALIPSO and 
CloudSat. 
      While useful, the FLASH SSF instantaneous 
data may not be conveniently formatted for use 
in all studies. Thus, the FLASH processing uses 
a three day moving window (CERES uses a 
monthly window) to create hourly gridded TOA 
* Corresponding author address: Paul W. Stackhouse, 
Science Directorate, NASA Langley Research Center, 
Hampton, VA, 23681-2199; e-mail:  
paul.w.stackhouse@nasa.gov. 
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https://ntrs.nasa.gov/search.jsp?R=20060028146 2019-08-29T22:14:39+00:00Z
and surface fluxes. These data can be easily 
processed to create daily gridded TOA and 
surface fluxes. Somewhat more involved is the 
temporal interpolation of the data to produce the 
FLASH TISA data product containing the daily 
and weekly averaged TOA and surface fluxes. 
Because Terra and Aqua are polar orbiting 
satellites, the measurements for most of the 
globe are taken at very specific local times.  To 
improve the quality of our temporally 
interpolated fluxes, we intend to incorporate 
geostationary narrowband radiances into future 
production of the FLASH TISA data sets. Such 
information will better define the time variation of 
the surface fluxes.  
       Another significant difference between the 
CERES and FLASHFlux processing involves 
code changes and improvements. Because the 
CERES data product is intended for climate 
research, the data product must be consistent 
throughout the entire length of the data record. 
The result is that alterations to the processing 
steam force a total reprocessing of the data. In 
contrast, since FLASH is intended for short-term 
immediate use, corrections and improvements, 
along with the appropriate documentation of the 
changes, can be implemented in real time. This 
allows FLASHFlux the flexibility to incorporate 
the most recent research into its algorithms. 
       All of the data sets produced by FLASHFlux 
are available at the NASA Langley Research 
Center Atmospheric Science Data Center 
(ASDC). The web site allowing access to the 
FLASHFlux datasets and their documentation is 
http://eosweb.larc.nasa.gov/PRODOCS/flashflux
/table_flashflux.html. In addition to the archived 
data sets, specially formatted data are planned 
for specific uses in atmospheric research and for 
applied science areas of energy management 
and agriculture. FLASHFlux will also have the 
flexibility to accommodate individual users who 
require specific data products. 
 
Figure 1: FLASHFlux data flow diagram showing all the subsystems that are denoted as follows: Meteorology, 
Ozone, Aerosol (MOA - violet), Clouds (blue), Inversion/Single Scanner Footprint (SSF - green), Spatial Gridding 
(yellow), Time Interpolation/Space Averaging (TISA - orange), Data Formatting (red), and Geostationary inputs 
(GGEO - grey). Squares indicate data sets; bold-shaped boundaries indicate inputs; bright-centers indicate 
outputs for end-users.  Circles indicate a processing algorithm. Red lines indicate subsystem transitions. 
 
2
3.   REQUIREMENTS 
 
     The purpose of the FLASHFlux project is to 
produce global and gridded radiative surface 
fluxes within one week of the CERES 
observations. Progress to date indicates this 
ambitious goal is attainable. Even though the 
FLASHFlux data sets require high accuracy, 
they are not intended for use in climate modeling 
which requires both exceptional accuracy and 
consistent processing throughout the entire data 
set. Thus, some degree of precision can, and 
has been traded, for efficiency. Initially, the 
temporal resolution will be daily averaged; 
however, once the geosynchronous satellite 
radiances are incorporated into the processing, 
we plan to begin producing synoptic scale hourly 
fluxes. 
 
4.   RESULTS 
 
4.1 Sample SSF Results 
 
      Representative TOA fluxes from the SSF 
data are presented in Figure 2.  The reflected 
SW, upwelling LW and total net fluxes are 
shown individually in the three plots comprising 
Figure 2 for the period of the June 14-16, 2004. 
Inverted from CERES radiances using the 
appropriate angular distribution models, these 
fluxes illustrate the results of a 3 day gridded 
composite at the afternoon overpass time.  No 
temporal interpolation has been performed at 
this stage. The figures show the standard 
expected features of increased SW reflected flux 
over clouds and bright surfaces such as the 
Sahara Desert.  The infrared shows maximums 
over warm, cloudless surfaces such as the 
deserts and the subtropical oceans.  The ITCZ 
in the tropics at this time is clearly seen by the 
increased SW reflected and the decreased LW 
fluxes.  In the total net, it is noted that the areas 
north of about 20 have a positive net (SW 
insolation dominating) with minima over bright 
surfaces such as the Sahara Desert and 
Greenland.  South of 20 S the total net is 
negative (LW dominated).  This is expected for 
June near the northern hemisphere’s summer 
solstice. 
      Figure 3 provides the radiative fluxes 
estimated at the surface using the radiative 
transfer algorithms noted above.  In this figure 
the SW down and SW net are given in the 
uppermost panels and the LW down and LW net 
are given in the bottom panels.  As expected for 
the June timeframe, the largest surface SW 
irradiance values are found near the North Pole, 
and in the vicinity of the northern hemisphere’s 
subtropics. Cloud system advection causes 
departures from zonal irradiance. The net SW 
fluxes have similar patterns but are also 
minimized over bright surfaces. Thus, as 
expected, the subtropical oceans received the 
largest amounts of solar energy.  LW surface 
fluxes dominate in the moist warm tropics, 
though decrease noticeably towards colder and 
drier areas.  Notable minima in the downward 
irradiances are observed over Tibet and the 
Andes where high elevations result in lower 
emission temperatures and lower water vapor 
amounts. Additional minima are observed over 
the desert regions of Australia and the Southern 
 
 
 
 
 
 
Figure 2: SSF all-sky fluxes from Aqua CERES as 
processed through the FLASHFlux processing 
system for June 14-16, 2004.  The top panel gives 
the SW reflected flux, middle is the LW outgoing 
flux and the bottom is the total net outgoing 
radiative flux. 
3
tip of Africa where Southern hemisphere winter 
and typically dry conditions also result in lower 
emission temperatures and lower water vapor 
amounts. The net LW have similar overall 
patterns although areas of strong negative net 
LW fluxes also occur over the warm but dry 
desert areas where emission to space is 
maximized. 
4.2 Instantaneous Validation of SSF fluxes 
 
      Validation for the SSF fluxes is obtained 
using surface measurements sites that report 
measurements quickly.  The SURFRad network 
in the US, which is also part of the Baseline 
Surface Radiation Network (BSRN), provides 
quality measurements shortly after observations.  
Such sites are appropriate for the monitoring 
and validation of FLASHFlux data products.  
Figure 4 gives the results of inter-comparison 
measurements from the Bondville, Illinois site 
relative to formal CERES SSF and FLASHFlux 
SSF flux estimates.  The plots were made for all 
instantaneous observations made during the 
months of Oct. 2004, and Jan. and Apr. 2005.  
The scatterplots and statistics show that the 
FLASHFllux SW and LW downwelling surface 
fluxes are compare favorably with the formal 
CERES products.  Similar comparisons are 
being performed for all available sites.   
 
4.3. SAMPLE DAILY VALIDATION RESULTS 
 
     The priority goal for the FLASHFlux endeavor 
is to temporally interpolate the gridded product 
to produce daily and weekly averaged TOA and 
surface fluxes. Figure 5 gives the hourly fluxes 
using the current interpolation methods over the 
3-day averaging window for the SW (top panel) 
and LW (bottom panel) fluxes. As demonstrated 
in Figure 5, the availability of both morning 
(Terra) and afternoon (Aqua) measurements 
greatly improves the retrieved fluxes. 
Nevertheless, rapid changes in meteorological 
conditions can introduce errors. Since the 
temporally averaged results are based upon 
individual satellite measurements, it is not 
surprising that the overall pattern of TOA and 
surface fluxes are similar to those presented in 
Figures 2 and 3. For the case of SW fluxes, 
however, the magnitude of the fluxes is 
noticeably reduced since the 24-hour daily 
average will include both daytime and nighttime 
periods.   
      The inclusion of GGEO subsystem (see 
Fig.1) will provide the opportunity to improve the 
temporal interpolation by providing short-term 
variability information. The inclusion of these 
measurements will lead to the opportunity to 
produce 1-3 hourly flux averages within the day.  
 
 
 
 
 
SW Down
Net SW
 
 
LW Down
Net LW
 
 
Figure 3: Surface radiative fluxes from FLASHFlux 
from the same period as Figure 2.  Shown are the 
SW down, SW net, LW down and LW net.  The 
SW plots share the same color bar. 
4
5.   CONCLUSIONS 
 
     The FLASHFlux endeavor has demonstrated 
the capability to produce high-quality surface 
fluxes, comparable to the climate-quality CERES 
fluxes, within a week of the satellite 
measurements. The project is operationally 
producing Single Scanner Footprint (SSF) 
radiance, cloud and radiative flux information 
within a week of observation.  The daily 
averaged fluxes that average over both Terra 
and Aqua satellite observations are expected to 
be operational within a month of writing this 
abstract. The FLASHFlux dataset fills the gulf 
between the climate-quality datasets and the 
synoptic meteorological measurements, and 
thus, provides a valuable, but long overdue, 
resource to users needing global and regional 
coverage of near real-time flux data. 
 
6.   REFERENCES 
 
Bloom., S. A. da Silva, and D. Dee, 2005: 
Documentation and validation of the Goddard 
Earth Observing System (GEOS) Data 
Assimilation System – Version 4. NASA 
Technical Report Series on Global Modeling and 
Data Assimilation, Max J. Suarez, Editor, 
NASA/TM-2005-104606, 26 pp.  
 
Gupta, S. K., D. P. Kratz, P. W. Stackhouse Jr., 
and A. C. Wilber, 2001:  The Langley 
Parameterized Shortwave Algorithm (LPSA) for 
surface radiation budget studies (Version 1.0).  
NASA/TP-2001-211272, 31 pp. 
 
Gupta, S. K., D. P. Kratz, A. C. Wilber, and L. C. 
Nguyen, 2004: Validation of Langley 
parameterized algorithms used to derive 
CERES/TRMM surface radiative fluxes. J. 
Atmos. Ocean Tech. 21, 742-752. 
 
Loeb, N. G., S. Kato, K. Loukachine, N. Manalo-
Smith, 2005: Angular distribution models for top-
of-atmosphere radiative flux estimation from the 
Clouds and the Earth’s Radiant Energy System 
instrument on the Terra satellite. Part I: 
methodology. J. Atmos. Ocean Tech. 22, 338-
351. 
 
Figure 4: Instantaneous validation between CERES and FLASHFlux surface radiative 
fluxes at Bondville, Illionis, SURFRad site. 
5
 
Mlynczak, M. G., D. G. Johnson, H. Latvakoski, 
K. Jucks, M. Watson, D. P. Kratz, G. Bingham, 
W. A. Traub, S. J. Wellard, C. R. Hyde, and X. 
Liu, 2006: First light from the Far-Infrared 
Spectroscopy of the Troposphere (FIRST) 
instrument. Geophys. Res. Lett., 33, L07704, 
doi: 10.1029/2005GL025114.  
 
Wielicki, B. A, B. R. Barkstrom, E. F. Harrison, 
Edwin F, R. B. Lee III, G. L. Smith, and J. E. 
Cooper, 1996: Clouds and the Earth's Radiant 
Energy System (CERES): an Earth Observing 
System experiment. Bulletin of the American 
Meteorological Society, Boston, MA. Vol. 77, no. 
5, pp. 853-868. 
 
Yang, S. K., S. Zhou, and A. J. Miller, 1997: 
SMOBA: A 3-Dimensional Daily Ozone Analysis 
Using SBUV and TOVS Measurements. This 
Publication has been made available through: 
http://www.cpc.noaa.gov/products/stratosphere/
SMOBA/smoba_doc.html 
 
 
 
 
Figure 5: TISA FLASHFlux surface validation for Sioux Falls, SD. 
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Fast Longwave and Shortwave Radiative Flux (FLASHFlux) Products from CERES and MODIS Measurements

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