GEWEX Radiation Panel Project Status Reports

GPCP Project Summary for October 2003

Global Precipitation Climatology Project (GPCP)

I. Project Status

A. Data Collection Systems

The basic input data continued to be collected from operational sensor systems as follows:

B. Data Processing Centers

All GPCP data processing centers have approval to operate through 2005 and are operating normally, except the SRT continues to re-build their TOVS processing software system due to a computer replacement. As a result, the GMDC is awaiting TOVS input to compute the final monthly and daily precipitation estimates for November 2002 forward, and CPC is awaiting final Version 2 SG fields to compute the pentad estimates for November 2002 forward. The SRT is currently doing end-to-end testing.

C. Data Processing Activities

Data products continued to be generated as follows:

The pending production issues are described in section IA.

D. Data Products Available-Archived

All intermediate data products are available from the respective producers some 1-2 months after the end of the data-month; all such products are current except for TOVS, which currently ends with October 2002.

The Version 2 SG monthly is available over the period January 1979 - October 2002 in final form and over November 2002 - July 2003 in provisional form.

The Pentad product is available over the period January 1979 - October 2002.

The 1DD product is available over the period January 1979 - October 2002 in final form and over November 2002 - July 2003 in provisional form.

The references for the GPCP monthly, pentad and daily products are as follows:

Adler, R.F., G.J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, A. Gruber, J. Susskind and P. Arkin, 2003: The version 2 Global Precipitation Climatology Project (GPCP) monthly precipitation analysis (1979-present). J. Hydrometeor., (in press).

Xie, P., J.E. Janowiak, P.A. Arkin, R. Adler, A. Gruber, R. Ferraro, G.J. Huffman and S. Curtis, 2003: GPCP pentad precipitation analyses: An experimental data set based on gauge observations and satellite estimates. J. Climate, 16, 2197-2214.

Huffman, G.J., R.F. Adler, M. Morrissey, D.T. Bolvin, S. Curtis, R. Joyce, B. McGavock, J. Susskind, 2001: Global precipitation at one-degree daily resolution from multi-satellite observations. J. Hydrometeor., 2(1), 36-50.

II. Important/Relevant Web Sites

The archive of record for GPCP is held at the National Climatic Data Center, NOAA/NESDIS in Asheville, North Carolina, USA:

		http://lwf.ncdc.noaa.gov/oa/wmo/wdcamet.html#GPCP

Other archives are held at:

		http://precip.gsfc.nasa.gov	for GMDC
		http://gpcc.dwd.de		  for GPCC

Related information is available at:

		http://orbit35i.nesdis.noaa.gov/arad/gpcp	for GPCP home page
		http://srdc.evac.ou.edu				       for SRDC validation

III. Notable Development Activities

A. On-going

TOVS processing: SRT at NASA GSFC is testing the re-built processing system for TOVS as well as prototyping a similar processing system for AIRS data.

Monthly provisional product: A monthly provisional product is being produced within two weeks of the end of the month for use by investigators. It was designed to provide a quasi-global analysis in a short time from the available data sets. Because of the timeliness of almost all of the data set providers, all the regular data sets are available, except for TOVS. Thus, the provisional product is incomplete at higher latitudes, but has proved useful in monitoring of ENSO and other tropical phenomena. The final, official product is produced when all input data sets are available.

IR normalization among geostationary satellites for GPCP: Joyce and Janowiak of GSPDC (NOAA/NWS/CPC) are working on comparing geostationary normalization techniques (theirs and ISCCP). Results are comparable and they recommend the ISCCP technique as the coefficients are now available in a timely manner.

Use of ISCCP geostationary IR data for histograms: Janowiak (NOAA/CPC) and Gruber (NOAA/NESDIS) are investigating using ISCCP IR data (DX) in various GPCP products to extend them back in time at daily and finer time scales. Up until late 1996 geostationary IR data was collected for GPCP in pentad histograms. This five-day grouping did not allow for daily or finer analysis. This is the main reason the GPCP daily product starts in October 1996. Comparison of histograms from overlapping periods will allow for understanding the impact of sub-sampling on possible applications. If schemes can be developed to substitute DX-based information for the available pentad histograms, the time resolution can be as fine as 3-hr. This would allow for the daily products to be extended back in time, through the SSM/I era (July 1987) and allow for a possibly finer time resolution (3-hr) product.

Development of fine-time scale precipitation analyses: A number of research/development efforts are underway by GPCP members and others to utilize multiple satellites to achieve finer time resolution analyses. At NASA/GSFC, Huffman/Adler are improving the TRMM-based Multi-satellite Precipitation Analysis (MPA) for research mode (TRMM Version 6) and real-time applications. At NOAA/CPC, Janowiak and colleagues are producing hourly results using a morphing strategy. Other investigators in the community are doing similar development. These products and others are being intercompared and compared against gauge information in Australia (Ebert) and the US (Janowiak). These products and their associated techniques are possible pathways to producing a GPCP fine time resolution product.

B. Planned

Working group on Version 3: A GPCP working group will be formed in the near future to discuss requirements and potential methods for developing a GPCP Version 3. The next version will incorporate a high time resolution product at least for a five-year period, use of TRMM data, and possibly updated algorithms for individual retrievals and merger techniques.

IV. Notable Research Results

New papers on the Version 2 monthly product and on the pentad product are published or "in press". GPCP data sets continue to be used by a number of investigators. A sampling is listed below.

Njessen, B., G.M. O'Donnell, D.P. Lettenmaier, et al., 2001: Predicting discharge of global rivers. J. Climate, 14, 3307-3323.

Rubel, F., and M. Hantel, 2001: BALTEX 1/6-degree daily precipitation climatology 1996-1998. Meteorol. Atmos. Phys., 77, 155-166.

Huffman, G.J., R.F. Adler, M. Morrissey, D.T. Bolvin, S. Curtis, R. Joyce, B. McGavock, J. Susskind, 2001: Global precipitation at one-degree daily resolution from multi-satellite observations. J. Hydrometeor., 2(1), 36-50.

Rubel, F., and B. Rudolf, 2001: Global daily precipitation estimates proved over the European Alps. Meteorol. Z., 10, 407-418.

Skomorowski, P., F. Rubel and B. Rudolf, 2001: Verification of GPCP-1DD global satellite precipitation products using MAP surface observations. Phys. Chem. Earth PT. B., 26, 403-409.

Tian, B.J., G.J. Zhang and V. Ramanathan, 2001: Heat balance in the Pacific warm pool atmosphere during TOGA COARE and CEPEX. J. Climate, 14, 1881-1893.

Kodama, Y.M., and A. Tamaoki, 2002: A re-examination of precipitation activity in the subtropics and the mid-latitudes based on satellite-derived data. J. Meteor. Soc. Japan, 80, 1261-1278.

Rubel, F., P. Skomorowski and B. Rudolf, 2002: Verification scores for the operational GPCP-1DD product over the European Alps. Meteorol. Z., 11, 367-370.

Yuan, J.C., and R.L. Miller, 2002: Seasonal variation in precipitation patterns to the global ocean: An analysis of the GPCP version 2 data set. Global Biogeochem. CY., 16, Art. No. 1103.

Curtis, S., G.J. Huffman and R.F. Adler, 2002: Precipitation anomalies in the tropical Indian Ocean and their relation to the initiation of El Niño. Geophys. Res. Lett., 29, 10.1029/2001GL013399.

Fu, Y.F., Y.H. Lin, G.S. Liu et al., 2003: Seasonal characteristics of precipitation in 1998 over East Asia as derived from TRMM PR. Adv. Atmos. Sci., 20, 511-529.

Klepp, C.P., S. Bakan and H. Grassl, 2003: Improvements of satellite-derived cyclonic rainfall over the North Atlantic. J. Climate, 16, 657-669.

Mitra, A.K., M. Das Gupta, R.K. Paliwal et al., 2003: Observed daily large-scale rainfall patterns during BOBMEX-1999. P. Indian AS-Earth, 112, 223-232.

Adler, R.F., C. Kummerow, D. Bolvin, S. Curtis and C. Kidd, 2003: Status of TRMM monthly estimates of tropical precipitation, In Symposium on Cloud Systems, Hurricanes and TRMM, Ed. W-K. Tao, R. Adler, Meteorol. Monogr., 29, No. 51, 223-234.

Curtis, S., and R.F. Adler, 2003: The evolution of El Niño-precipitation relationships from satellites and gauges. J. Geophys. Res., 108, 10.1029/2002JD002690.

Xie, P., J.E. Janowiak, P.A. Arkin, R. Adler, A. Gruber, R. Ferraro, G.J. Huffman and S. Curtis, 2003: GPCP pentad precipitation analyses: An experimental data set based on gauge observations and satellite estimates. J. Climate, 16, 2197-2214.

Adler, R.F., G.J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, A. Gruber, J. Susskind and P. Arkin, 2003: The version 2 Global Precipitation Climatology Project (GPCP) monthly precipitation analysis (1979-present). J. Hydrometeor., (in press).

Gebremichael, M., W. Krajewski, M. Morrissey, D. Langerud, G. Huffman and R. Adler, 2003: Error uncertainty analysis of GPCP monthly rainfall products: A data based simulation study. J. Appl. Meteor., (in press).

Curtis, S., R. Adler, G. Huffman and G. Gu, 2003; Westerly wind events in the eastern Indian Ocean as a precursor to El Niño: A case study for the 2002-03 El Niño. J. Climate, (submitted).

V. Problems/Issues

(1) TOVS-based precipitation estimates: The SRT, which provides the TOVS precipitation estimates that are used primarily in high latitudes for both the monthly and daily products, is significantly behind schedule (November 2002) due to a computer replacement. It is expected that they will soon resolve the problem and catch up in a few months. They will also be supplying estimates based on AIRS retrievals to complement the TOVS-based estimates. The SRT is not specifically funded to provide the TOVS estimates.

(2) Limitations of gauge analysis is terrain: The monthly product has been shown to have a negative bias in certain areas of complex terrain. This effect has been traced to limitations in the gauge data and analysis. Solutions will require gauge analysis incorporating the effect of terrain and/or different merger methods or weighting to increase the emphasis on the satellite estimates.

(3) TRMM lifetime: TRMM data will be incorporated into the GPCP Version 3 and TRMM information will likely be used to calibrate the entire GPCP record. TRMM has the potential to last until 2011, but NASA budget issues and issues related to orbital debris may limit its lifetime to as early as 2004.

SRB Project Summary for October 2003

GEWEX Surface Radiation Budget Project (SRB)

I. Project Status: Processing, Archival and Documentation

The WCRP/GEWEX Surface Radiation Budget (SRB) project has produced a 12+ year (148 months) data set spanning July 1983 - October 1995 for the GEWEX SW, SW Quality Check (QC), GEWEX LW and LW QC flux algorithms. Monthly and daily averaged data from three of these data sets are archived at the NASA Langley Atmospheric Sciences Data Center (ASDC) and available to the public. Concurrently, with the data processing are activities in validation and analysis of the data sets. This project has been selected by NASA Headquarters to continue through April 2006. The level of funding is such that nearly all proposed upgrades, validation, processing and archival activities will continue. The following report summarizes the status of SRB.

A. Data Collection Systems

SRB uses satellite data from ISCCP, meteorological data from the NASA Global Modeling and Analysis Office (GMAO, formerly the DAO) and ozone data from TOMS (and TOVS when needed). All data required for SRB Release 2 have been obtained. All data are archived at the NASA Langley ASDC. All ISCCP data are also archived at ASDC, which will act as the data source for continued processing. The SRB project will collect other data inputs as needed.

B. Data Processing Centers

The processing for SRB Release 2 was performed by the SRB project and at the NASA Langley ASDC. ASDC has been funded by NASA through the main NASA SRB proposal. A renewal proposal has been selected by NASA Headquarters at 85% of the requested amount. The SRB plan is being revised under these budget constraints but funds are sufficient for continued development and reprocessing.

C. Data Processing Activities

The processing for SRB Release 2 has now been completed for all algorithms. Processing for special overlap months with Clouds and Earth's Radiant Energy Systems (CERES) Surface and Atmospheric Radiative Budget and Surface-Only Flux Algorithms is planned as soon as ISCCP completes its re-processing of DX for 1998 and beyond (within about one month). Processing beyond 1995 will commence upon resolution of issues regarding input meteorology.

D. Data Products Available/Archived

Monthly and daily averaged products are available from the SW, SW QC and LW QC algorithms. README, software and data set description files have been completed for these data sets. Monthly averaged 3-hourly and 3-hourly quantities from these algorithms will be archived shortly (by November 2003). Monthly and 3-Hourly-Monthly averaged fluxes have been supplied to ISLSCP for inclusion into their Initiative II CD set. Flux and input properties are being provided to support the European Surface Radiation Budget project that concentrates on the Mediterranean region. Flux and ancillary products from the LW algorithm are also being prepared for archival in November 2003.

II. Important/Relevant Web Sites

The main SRB web site is being revised in design and content. Links are being developed for users to plot the data sets via the web. The current web site is:

		http://srb-swlw.larc.nasa.gov/Pilot_homepage.html

(this web site name will probably be changed and this information will be forwarded to the GEWEX International Project Office and GRP as soon as possible).

All data from SRB Release 2 are available via the NASA Langley ASDC DAAC. The web site for the data is:

		http://eosweb.larc.nasa.gov/PRODOCS/srb/table_srb.html

III. Notable Development Activities and Plans

A. On-going

1. Validation activities:

a. Coldest/Brightest Albedo Check: Narrowband albedos have been computed for years 1984-1995 for all pixels containing brightness temperatures less than 205 K assumed to be representative of deep convective clouds. Time series of the seasonally averaged albedos are compared between each satellite to examine consistency of the gain between the satellites and variability in time. This procedure is to be more rigorously analyzed under the new proposal.

b. Assessment of long-term SW fluxes: The SRB SW fluxes were compared against long-term SW measurements from the World Radiation Data Centre (WRDC) database for July 1983 - December 1993 (end of database) and the Canadian network measurements. Comparisons were performed in an overall sense and in sets of clusters of sites in common climatological regions.

c. BSRN/ARM comparisons: SW and LW fluxes were compared against BSRN measurements from January 1992 - October 1995 on a monthly averaged and daily basis. Comparisons are being made and results evaluated for errors on a 3-hourly monthly averaged and 3-hourly basis. Assessments against ARM measurements in 1998 led to some refinement of the algorithm before processing.

d. ERBE comparisons: Long-term comparisons to TOA reflected SW and outgoing LW are being conducted to assess the TOA flux variability.

e. Aerosol assessment: Several case studies of extreme aerosol events have been developed to be used in the testing of a future improved historical aerosol map. SRB fluxes have been evaluated during these events.

2. Intercomparison activities:

a. First EOS intercomparison: The EOS intercomparison will be redone afer ISCCP reprocesses 1998 and onward.

b. Comparison to reanalysis: The previous intercomparison with NCEP R2 and ERA-40 for the EOS time periods will be redone once ISCCP reprocesses 1998 and beyond. However, we are evaluating ERA-40 meteorology and NCEP R2 meteorology for 1992. Both are candidate datasets for processing SRB past 1995.

B. Planned

1. Web-based product subsetting and plotting: In collaboration with the LARC ASDC, a subsetting capability for the datasets will be added for ease of use and data access. Also web-based plotting capability for user-defined parameters is being added and will be linked to the upgraded SRB web site.

2. 3-Hourly cloud/ancillary products: 1 x 1 degree 3-hourly cloud and ancillary properties will be added to the archives. The selected properties will be those input into the flux algorithms to enable collaborative intercomparison and improvement.

3. Validation/intercomparison activities: SRB will continue and extend the validation and intercomparison of surface and TOA flux estimates against satellite and surface measurements such as CERES, SARB/SOFA, NASA GISS, etc. also SRB will extend the surface analysis to include direct and diffuse SW fluxes and PAR fluxes with an emphasis on validating these under various sky conditions.

4. Development activities: Under the new proposal several research activities are being pursued with a goal of a total reprocessing beginning in mid-2005. These are:

a. Refine analysis of coldest/brightest pixel albedos: The time series analysis of convective cloud albedos will be refined and compared to VIRS/MODIS at CERES times.

b. In collaboration with Dr. Rachel Pinker of Univ. of Maryland, SRB will adapt the new CERES-based Angular Distribution Models to the GEWEX SW flux algorithm and improve the narrow-to-broadband relationships using CERES and VIRS/MODIS radiances.

c. In collaboration with Dr. Rachel Pinker, SRB will upgrade the surface spectral albedos used in the flux calculations. We have already exchanged surface albedo and spectral emissivity maps with those used by NASA GISS. SRB will also collaborate with CERES SARB and NASA GISS to upgrade surface emissivity properties.

d. SRB will improve various cloud and boundary layer assumptions in the GEWEX LW flux code.

e. SRB will develop a new historical background aerosol map in collaboration with Mian Chin and the GOCART model. This new map will be tested and used in calculations of the surface radiation and direct aerosol radiative forcing.

IV. Notable Results

A. Analysis results

1. Multi-year analysis: Computed 12-yr mean values for surface radiation parameters and surface cloud radiative forcing and compared these to other past/present project results. Compared long-term time series deseasonalized anomalies of the surface and TOA fluxes to surface and ERBE measurements. Assessed variability of surface and TOA fluxes for different regions. EOF analysis is now being pursued. Collaborating with NASA GISS to write long-term analysis paper for BAMS.

2. Tropical Pacific: Anomalies in the tropical Pacific were examined on local (grid box level) and regional bases. We find SW and LW flux anomalies compared to the 7-yr mean during the 1992 El Nino and 1988 La Nina exceed 40 Wm² on a monthly basis. The spatial scales of the responses to these events were noted. A monthly averaged time series of the response in the eastern Pacific region (20S - 20N, 180 - 120W) mirrors very well the multi-variate El Nino index. The region in the western Pacific had no such correlation and indicated differences in the spatial scales of response. Data for the western Pacific region were compared to TOGA-COARE measurements during the November 1992 - February 1993 period.

3. Meteorological input assessment: Collaborating with NASA GISS/ISCCP to complete comparison of meteorological input datasets including the NASA GEOS Version 1 reanalysis (GEOS1), the European Center for Medium-Range Weather Forecasts 15-yr reanalysis (ERA-15), the NASA Water Vapor Project (NVAP) and the ISCCP meteorological parameters (from NOAA TOVS). The comparison includes the diurnal cycles. New ERA-40 data will be added to this comparison.

4. Aerosol radiative forcing, Ilorin, Nigeria: At Ilorin, Nigeria, a distinct bias is seen between SRB and BSRN fluxes. The bias increases and then fades from November through February each year. The cause of this bias is being studied by analyzing the surface measurements and using the Fu/Liou radiative transfer model. After developing a method to infer clear-skies, aerosol radiative forcing is computed and found to often exceed 200 Wm², particularly during the months of December and January. This bias is believed to be caused by aerosols resulting from dust and biomass burning events that are not included in the flux calculations. This case study will become a key in the development of the historic aerosol background maps.

B. Recent References

Chiacchio, M., J. Francis and P.W. Stackhouse, 2002: Evaluation of methods to estimate the surface downwelling longwave flux during arctic winter. J. Appl. Meteor., 41, 306-318.

Smith, G.L., A.C. Wilber, S.K. Gupta and P.W. Stackhouse, 2002: Surface radiation budget and climate classification. J. Climate, 15, 1175-1188.

(3 papers in preparation)

V. Problems/Issues

1. What meteorological input should be used for continued SRB processing past 1995? Candidates are ERA-40, NCEP R2 and GEOS 4.0.3. Issues involve possible costs and redistribution limitations for ERA-40. NASA GMAO is considering processing GEOS 4.0.3 at nearly 1x1.25 degree resolution from 1998 through 2003 to support CERES. They are also considering processing pre-1998. These negotiations are on-going. GEOS 4.0.3 could be available for total SRB processing in 2005.

2. The SRB plan must be revised to accommodate the budget constraints.

BSRN Project Summary Report for October 2003

Baseline Surface Radiation Network (BSRN)

I. Project Status

A. Data Collection Systems

The collection system consists of approximately 35 surface sites collecting at a minimum the downwelling solar and thermal infrared hemispheric irradiances. Basic meteorological variables and routine upper air soundings are also made at most of the sites. The measurements are continuous, resolving one- to three-minute averages and standard deviations of 1 Hz sampling. Additional observations of upwelling irradiances, spectral atmospheric transmission (for aerosol optical depth), UVB and ozone are made at some of the sites as resources and conditions allow. The actual number of sites varies as additional active sites are added to the network. To date, no site that has started collecting data and supplying that data to the BSRN archives has permanently discontinued doing so, although some submissions can be several years after collection. Several new candidate sites are being proposed, some of which fill substantial gaps in the global representativeness of the network, some of which are being developed as part of other highly visible and well-financed projects where extensive ancillary data of interest to the BSRN community will be acquired but which do not necessarily extend the global representativeness of the network. An integral part of the network is the interaction of the participants in sharing of ideas and new methodologies which is accomplished by numerous informal contacts and bi-annual project-wide meetings.

Although the original intent of the BSRN was to provide direct observations of surface irradiances at globally remote and regionally representative sites, interests and demands of the project have expanded that mission. This expansion includes obtaining and supplying the ancillary information necessary to model the surface irradiances so the capabilities with different constraints can compare the irradiances they derive with those directly observed. These additional observational needs relate to the presence of aerosols, clouds and water vapor in the atmosphere, as well as the atmospheric state variables and surface reflectance. BSRN continues to expand these observations by analyzing the current measurement capabilities and proceeding by establishing specifications for measurement systems that will supply data of the necessary quality. The procedures for implementing network-wide aerosol optical depth measurements are being established and the evaluation of UVB and PAR measurement capabilities are under way. New methods for determining cloud base height are being investigated and future measurements of spectral irradiance and non-radiative heat fluxes are being considered. Such relatively sophisticated and costly measurements could only be done if the necessary funding can be obtained.

B. Data Processing Centers

The Archive Center is funded on a multi-year cycle through the ETHZ which receives funding from the Swiss federal government and some other sources secured by the Archives manager. Current funding is essentially complete for about three or more years with discussions on longer-term security underway with the Swiss federal government and with other national governments expressing an interest in supporting the Archives should the Swiss not be able to continue.

C. Data Processing Activities

The basic field data are processed by individuals and groups responsible for the operational site where the data are collected. There are standard procedures for the calibration and operation of the instrumentation with the quality control of the data maintained by the designated site scientist. Field data are prepared in a specific format and supplied to the central BSRN Archives at ETHZ (Swiss Technical Institute, Zurich). The Archives applies additional quality assurance tests but does not modify the data in any way. The results of the QA tests are available along with the data as submitted. The Archives distributes the data on demand in two different ways, a web-based relational database format and from an ASCII file system for ftp distribution. The ftp distribution system was recently implemented and included an updated QA application that was not practical within the constraints of the database management system.

D. Data Products Available/Archived

The archived data block from each site consists of a monthly file of the minute-resolution irradiances and meteorology with statistics on the irradiance averages. Data from a total of 34 different surface sites were available as of 19 October 2003. A total of 2524 months of data are available from those sites with the longest record going back to 1992 and the most recent data from June 2003, although most of the sites have a lag of 6 months or longer. Often delaying the submission of the basic irradiance data to the Archives is the desirability of including the upper air soundings with the submission. Also, the necessity of post facto calibrations and other on-site quality control can delay data submission indefinitely but typically not more than 2 years.

II. Important/Relevant Web Sites

The official BSRN web site is maintained by the Archives, also known as the World Radiation Monitoring Center at

		http://bsrn.ethz.ch

This site also maintains a list of other relevant web sites.

III. Notable Development Activities

A. On-going

The BSRN has been the international focal point for several developmental projects intended to secure the long-term capability for accurate centralized measurements of surface broadband surface irradiances. To this end, BSRN was involved in the development of international consensus reference standards for both solar diffuse irradiance and hemispheric thermal IR irradiance. The next in a series of intensive observing session intended to evaluate current capability and assess the degree of convergence will be conducted in October 2003, where the goal is solidification of our understanding of the technologies fr producing an absolute solare diffuse reference. Never in the history of atmospheric radiation measurements as there been either a solar diffuse or a thermal IR irradiance reference standard. Prior to the BSRN the best-case uncertainties of order 30 Wm² were common. Now the uncertainties of the candidate references are less than 5 Wm².

B. Planned

BSRN has a working group exploring the use of commercial IR thermometers to analyze the cloud-induced signals and to identify cloud occurrence and base height information. There are also exploratory efforts in the area of spectral solar irradiance and non-radiative energy flux measurements, although the proliferation of these types of measurements in the whole BSRN is a "distant" potential.

IV. Notable Research Results

Lee, H-T., and R.G. Ellingson, 2002: Development of a nonlinear statistical method for estimating the downward longwave radiation at the surface from satellite observations. J. Atmos. Oceanic Tech., 19, 1500-1515.

Jin, Z., T.P. Charlock and K. Rutledge, 2002: Analysis of broadband solar radiation and albedo over the ocean surface at COVE. J. Atmos. Oceanic Tech., 19, 1585-1601.

Michalsky, J.J. et al., 2003: Results from the first ARM diffuse horizontal shortwave irradiance comparison. J. Geophys. Res., 108, 10.1029/2002JD002825.

Morcrette, J-J., 2002: The surface downward longwave radiation in the ECMWF forecast system. J. Climate, 15, 1875-1892.

Philipona, R., 2002: Underestimation of solar global and diffuse radiation measured at Earth's surface. J. Geophys. Res., 107, 10.1029/2002JD002396.

Zhang, Y., Z. Li and A. Macke, 2002: Retrieval of surface solar radiation budget under ice cloud sky: Uncertainty analysis and parameterization. J. Atmos. Sci., 59, 2951-2965.

Mitchell, R.M., and B.W. Forgan, 2003: Aerosol measurement in the Australian outback: Intercomparison of sun photometers. J. Atmos. Oceanic Tech., 20, 54-66.

Marty, C., R. Philipona, J. Delamere, E.G. Dutton, J. Michalsky, K. Stamnes, R. Storvold, T. Stoffel, S.A. Clough and E.J. Mlawer, 2003: Downward longwave irradiance uncertainty under arctic atmospheres. J. Geophys. Res., 108, 10.1029/2002JD002937.

V. Problems/Issues

A long-term sustained observing activity, such as the field operations of BSRN, has an inherent problem of maintaining itself in a scientific environment where the expectation of short-term results with short-term funding is the norm. BSRN has flourished in that environment primarily because it is made of numerous national radiation monitoring efforts that have been traditionally sustained by their respective countries. Those related problems aside, the largest issue facing BSRN currently is addressing the solicitation for the participation of BSRN in the Global Climate Observing System (GCOS). GCOS is sponsored largely by the same parent organizations as WCRP. The consensus of BSRN participants and supporters is that BSRN should cooperate with GCOS and allow the designation as the GCOS global surface radiation network under the condition that BSRN remain entirely within the realm of WCRP and GEWEX and that BSRN will establish the criteria by which the GCOS radiation network will operate. BSRN will, in turn, make every effort to implement and abide by the GCOS monitoring principles, which are actually very sound principles for conducting long-term measurements for climate-related research. BSRN has no inherent problem with implementing these principles.

BSRN is in the process of assessing the extent of residual thermal offset errors in the diffuse solar irradiance values archived in Zurich. The related problems have been corrected at virtually all the sites for the past couple of years and either never existed at some sites or have been corrected in the data and resubmitted for other sites.

BSRN is in the process of implementing aerosol optical depth measurements as an optional additional measurement for the network. Such observations are currently being made at many of the sites under the specifications developed by and for BSRN. The remaining step in making these data available through the archives is the implementation of the software and procedures for centrally processing the data from the spectral transmission values supplied by the field sites into spectral optical depths. This task will be implemented at the World Optical Depth and Calibration Center in Davos, Switzerland.

ISCCP Project Summary for October 2003

International Satellite Cloud Climatology Project (ISCCP)

I. Project Status

A. Data Collection Systems

ISCCP completed its 20th year of data collection on 30 June 2003. Radiances from all operating meteorological satellites, with the exception of FY-2B, are being routinely collected by the cognizant Sector Processing Centers (SPC) and delivered to the Global Processing Center (GPC) and International Archives Center (ICA) in accordance with project requirements. All project datasets are now being delivered via Internet except for the DX product. Currently operating satellites are NOAA-16, NOAA-17, GOES-9, GOES-10, GOES-12, METEOSAT-5 and METEOSAT-7 with METEOSAT-6 and GOES-11 in reserve. GOES-12 replaced GOES-8 on 1 April 2003. METEOSAT-5 is located at 63E longitude, providing coverage of the Indian Ocean -- Asia sector since July 1998. MSG-1 was launched in 2002 and is going through an extensive commissioning phase; it is not planned to be fully operational until 2005. At that time, METEOSAT-6 will be moved to provide coverage of Asia. METOP-1 launch is planned for 2005. GOES-9 is now located at 155E longitude, replacing GMS-5 on 22 May 2003. The launch of MTSAT-1R is now scheduled for early 2004. China successfully launched FY-1D (polar orbiter) in 2002 and plans to introduce a much more advanced polar orbiter, FY-3, in 2005. ADEOS-2 was successfully launched on 14 December 2002.

Atmospheric temperature and humidity profiles from NOAA NESDIS and the sea ice and snow correlative datasets from NSIDC have been received through June 2003.

B. Data Processing Centers

All participating data centers have approval to operate through at least 2005 and are operating normally except MSC in Canada, which has encountered a number of problems with the switch from GOES-8 to GOES-12 that involve re-arranging how data are collected and processed within their organization. NOAA National Climatic Data Center took over the ISCCP SPC/ICA functions within NOAA during the past year.

C. Data Processing Activities

All Sector Processing Centers (EUM, JMA, MSC, CSU, NOAA) are processing Stage A data into Stage B1/B2 normally except for MSC. CSU is collecting and processing GOES-12 data as backup to MSC.

The Satellite Calibration Center (SCC) in Lannion, France, provides monthly satellite-to-satellite radiance normalization for four wavelength channels, nominally at 0.6, 6.7, 11 and 12 µm (when available). Normalization data are complete through June 2003.

The Global Processing Center (GPC) monitors the calibration of the polar orbiting radiometers (AVHRR) that serve as the reference standard for the radiance data. Monitoring results are complete through July 2003. Up-to-date calibration information is posted on the ISCCP Web page. Routine archival of Stage B3 data is complete through September 2001. NOAA-16/17 data have been processed through July 2003. Since the newer satellites have more than five wavelength channels, the ISCCP Stage B3 format was re-designed. Processing of the atmospheric temperature and humidity profiles is complete through September 2001, when the format and contents of the NOAA dataset changed; processing of the sea ice and snow correlative dataset is complete through June 2003. Stage DX, D1 and D2 data have been completed for July 1983 through September 2001 (18.25 years).

An error in the processing of the Snow/Ice (SI) product was discovered that does not affect the delivered SI product, but does affect the D-data products for 1998 onwards. These data will be re-processed. Processing of D-data beyond September 2001 is delayed until the cloud algorithm can be revised to account for the fact that the newer AVHRRs (sometimes) switch between a channel operating at 1.6 µm and one at 3.7 µm during the daytime.

The current estimate of processing schedule is as follows:

(1) Complete and deliver Stage B3 and correlative datasets for October 2001 through March (or June) 2003 by November of this year.

(2) Complete re-processing of Stage D datasets for 1998-2001 by early November.

(3) Complete and deliver Stage D datasets for October 2001 through March (or June) 2003 by the end of this year.

(4) Process all data products through December 2003 by June 2004.

(5) Continue processing data products with six-month time lag.

(6) After a research phase involving new satellite measurements during 2004 and 2005, the whole ISCCP data collection will be re-processed in 2006-2007.

D. Data Products Available-Archived

Complete datasets currently available at the ICA are:

Stage B3 and BT: July 1983 -- September 2001

Atmospheric data: July 1983 -- September 2001

Sea ice and snow data: July 1983 -- June 2003

Stage DX, D1 and D2: July 1983 -- September 2001

Three CDs of D2 data have been released covering the periods 1983 - 1988, 1989 - 1993 and 1994-1998. All D2 data (1983 - 2001) are now on-line on the ISCCP Web site.

II. Important/Relevant Web sites

The ISCCP Web pages can be found at:

		http://isccp.giss.nasa.gov

A separate Home page for the GEWEX Cloud System Study - Data Integration for Model Evaluation (GCSS - DIME) can be found at:

		http://gcss-dime.giss.nasa.gov

Two papers about these Web sites have been submitted to the Bulletin of the American Meteorological Society:

Rossow, W.B., and E. Duenas, 2003: The International Satellite Cloud Climatology Project (ISCCP) Web site: An on-line resource for research into the role of cloud and radiation processes in climate. Bull. Amer. Meteor. Soc., (submitted).

Tselioudis, G., W.B. Rossow, A.N. Gentilcore and J. Katzfey, 2003: The Data Integration for Model Evaluation (DIME) Web site: A one-stop shop for model evaluation. Bull. Amer. Meteor. Soc., (submitted).

III. Notable Development Activities

A. On-going

Since sampled AVHRR data were obtained back to the beginning of the life of NOAA-7 in August 1981, these data have been processed to provide coverage of the El Nino and the El Chichon eruption in 1982-83. A special polar-orbiter-only climatology will be prepared (with an adjustment for limited diurnal sampling) to produce a 20+yr record of ENSO anomalies.

Four diagnostic products are being worked on.

(1) A survey of midlatitude cyclone-anticyclone cloudiness is produced by combining the NCEP re-analysis with ISCCP: this survey has been completed and the results are being prepared for publication and for posting to the ISCCP Web site.

(2) A survey of tropical mesoscale convection is produced by identifying and tracking the motions of all high-cloud clusters that contain convective clouds at some stage: this survey has been completed for 1998-2000 and is being analyzed together with TRMM precipitation and lightning data. Software and a database that allows for matching TRMM (or any other) observations to the tracking results will be posted to the ISCCP Web site. The remaining years will be then processed early next year.

(3) A method to retrieve cloud particle sizes, for both liquid and ice clouds is being assembled and will be tested later this year. A climatology covering the whole ISCCP time period should be ready early next year.

(4) A complete analysis of radiative flux profiles at mesoscale resolution has been completed, providing global, 3-hr fluxes for the period July 1983 through June 2001 (this product will be extended as more ISCCP data becomes available). Samples of this product have been posted on the ISCCP Web site. The complete products include separate top-of-atmosphere and surface radiative fluxes, the full atmospheric profile of radiative fluxes and the complete input dataset used to determine the radiation.

Preparations are underway to allow processing of a 5-km-sampled version of MODIS radiances to be processed by the ISCCP analysis software.

B. Planned

The processed 5-km-sampled MODIS radiances will be used for cross-calibration of MODIS to

ISCCP radiances and for comparison of ISCCP to other MODIS-based cloud products next year. This investigation will then be extended to include MISR and AIRS/AMSU/AMSR.

An investigation is being made as to the feasibility of substituting the processing of Stage B1 radiances for Stage B2 radiances in the next re-processing cycle of ISCCP. This substitution would increase the sampling of the ISCCP products to 10 km from 30 km.

The GPC is now funded through 2007. Proposed activities are as follows.

(1) Process and deliver current version of the ISCCP products for October 2001 - June 2006, providing a 23-yr climatology.

(2) Produce first cloud particle size survey and merge with GACP aerosol data product; extend to polar clouds.

(3) Complete re-analysis of calibration and sampling of whole ISCCP radiance dataset (and possibly make the switch to B1 from B2).

(4) Refine polar cloud detections by comparison with data from SHEBA, MODIS, AIRS, POLDER, CloudSat, Calipso, and other advanced satellite instruments.

(5) Refine cirrus identification and to remove/reduce spurious angle dependence in the ISCCP results by comparison with data from MODIS, MISR, AIRS, POLDER, Calipso and other advanced satellite instruments.

(6) Complete modifications of the ISCCP analysis procedure to remove aerosol effects (based on SAGE and GACP) and to improve retrievals of surface reflectance and temperature.

(7) Process and deliver revised ISCCP products for July 1983 - June 2007 (24-yr climatology)

IV. Notable Research Results

New scientific result based on the ISCCP datasets are reported in:

Han, Q., W.B. Rossow, J. Zeng and R. Welch, 2002: Three different behaviors of liquid water path of water clouds in aerosol-cloud interactions. J. Atmos. Sci., 59, 726-735.

Rossow, W.B., C. Delo and B. Cairns, 2002: Implications of the observed mesoscale variations of clouds for Earth's radiation budget. J. Climate, 15, 557-585.

Stubenrauch, C.J., V. Briand and W.B. Rossow, 2002: The role of clear sky identification in the study of cloud radiative effects: Combined analysis from ISCCP and the Scanner of Radiation Budget (ScaRab). J. Appl. Meteor., 41, 396-412.

Luo, Z., W.B. Rossow, T.Inoue and C.J. Stubenrauch, 2002: Did the eruption of the Mt. Pinatubo volcano affect cirrus properties? J. Climate, 15, 2806-2820.

Zhang, Y-C., and W.B. Rossow, 2002: New ISCCP global radiative flux data products. GEWEX News, 12, No. 12, 7.

Rozendaal, M., and W.B. Rossow, 2003: Characterizing some of the influences of the general circulation on subtropical marine boundary layer clouds. J. Atmos. Sci., 60, 711-728.

Aires, F., C. Prigent and W.B. Rossow, 2003: Temporal interpolation of global surface skin temperature diurnal cycle over land under clear and cloudy conditions. J. Geophys. Res., (submitted, revised).

V. Problems/Issues

There are currently three issues: (1) whether or not the TOVS atmospheric temperature and humidity profiles can be re-processed to improve their quality in time for use in the re-processing of the ISCCP products, (2) concern about the fact that the funding approvals for the participating ISCCP centers do not cover the same time periods, and (3) concern that support is not available to transition the remaining parts of the ISCCP project (primarily the SCC and GPC functions) from research to operational institutions.

GACP Project Summary Report for October 2003

Global Aerosol Climatology Project (GACP)

I. Project Status

A. Data Processing Activities

Following the completion of Stage DX, D1 and D2 ISCCP data for July 1983 through September 2001 (18.25 years), the GACP aerosol product has been derived and is available for the same period.

An error in the processing of the Snow/Ice (SI) product was discovered that may affect the ISCCP D-data products for 1998 onwards. After these data have been re-processed, we will analyze the significance of this error on the aerosol product. The expected dely in the processing of the ISCCP D-data beyond September 2001 will similarly delay the GACP aerosol products.

The current estimate of the processing schedule is as follows:

(1) Complete and deliver GACP datasets for October 2001 through March (or June) 2003 by August 2004.

(2) Deliver GACP data products through December 2003 by January 2005.

B. Data Products Available/Archived

Complete GACP datasets currently available at the GACP web site are the monthly averages of the aerosol optical thickness and Ångstrom exponent for the period from July 1983 through September 2001.

II. Important/Relevant Web Sites

The GACP Web pages can be found at

http://gacp.giss.nasa.gov

III. Notable Development Activities

A. On-going

We are working on the validation and fine-tuning of the aerosol retrieval algorithm based on various kinds of in situ, ground-based, and aircraft data. The ground-based datasets currently being analyzed are the extensive sun-photometer records obtained from cruise ships by Smirnov et al. during the 1980's and 1990's. We are also trying to use the AERONET dataset, although there appear to be significant problems with this comparison.

Another current activity is to combine the SAGE and AVHRR datasets to refine the aerosol data record by separating stratospheric from tropospheric components during the major volcanic events.

B. Planned

The GACP is now funded through 2006. Proposed activities are as follows.

(1) Finalize the development of a flexible and compact aerosol retrieval algorithm and process standard aerosol products for the period October 2001 - December 2005.

(2) Quality check and calibrate AVHRR channel-1 and -2 radiance data.

(3) Refine AVHRR retrievals over areas dominated by nonspherical mineral aerosols.

(4) Examine the information content of AVHRR channel-3A radiances and the potential of a channel-1/3A retrieval algorithm.

(5) Investigate anomalies and regional trends in the retrieved aerosol properties.

(6) Compare derived aerosol properties over oceans with new satellite data products from MODIS and MISR.

(7) Investigate the potential of AVHRR aerosol retrievals over land areas and compare them with the coincident MODIS and MISR aerosol retrievals.

(8) Refine the GACP analysis procedure after comparisons with SAGE and MODIS/MISR and re-process the long-term aerosol dataset.

(9) An investigation is being made as to the feasibility of substituting the processing of Stage B1 radiances for Stage B2 radiances in the next re-processing cycle of ISCCP. This substitution would increase the sampling of the GACP products to 10 km from 30 km.

(10) Merge the AVHRR and MODIS/MISR data records.

(11) Combine the aerosol and ISCCP cloud retrieval algorithms, use both for simultaneous operational retrievals of cloud and aerosol properties, and re-process the entire aerosol dataset using an updated ISCCP radiance calibration and cloud detection procedures (both are expected to be available in 2005).

(12) Analyze the combined aerosol/ISCCP cloud product to assess the magnitude of the indirect aerosol effect.

(13) Maintain the GACP web site.

IV. Notable Research Results

New scientific results based on the GACP datasets are reported in the following peer-reviewed publications.

Kinne, S., U. Lohmann, J. Feichter, M. Schulz, C. Timmreck, S. Ghan, R. Easter, M. Chin, P. Ginoux, T. Takemura, I. Tegen, D. Koch, M. Herzog, J. Penner, G. Pitari, B. Holben, T. Eck, A. Smirnov, O. Dubovik, I. Slutsker, D. Tanre, O. Torres, M. Mishchenko, I. Geogdzhayev, D.A. Chu and Y. Kaufman, 2003: Monthly averages of aerosol properties: A global comparison among models, satellite data, and AERONET ground data. J. Geophys. Res., 108, 10.1029/2001JD001253.

Myhre, G., F. Stordal, M. Johnsrud, A. Ignatov, M.I. Mishchenko, I.V. Geogdzhayev et al., 2003: Intercomparison of satellite retrieved aerosol optical depth over ocean. J. Atmos. Sci., (in press).

Mishchenko, M.I., I.V. Geogdzhayev, L. Liu, J.A. Ogren, A.A. Lacis, W.B. Rossow, J. Hovenier, H. Volten and O. Muñoz, 2003: Aerosol retrievals from AVHRR radiances: Effects of particle nonsphericity and absorption and an updated long-term global climatology of aerosol properties. J. Quant. Spectrosc. Radiat. Transfer, 79/80, 953-972.

Liu, L., M.I. Mishchenko, J.W. Hovenier, H. Volten and O. Muñoz, 2003: Scattering matrix of quartz aerosols: Comparison and synthesis of laboratory and Lorenz-Mie results. J. Quant. Spectrosc. Radiat. Transfer, 79/80, 911-920.

Yu, H., R.E. Dickinson, M. Chin, Y.J. Kaufman, B.N. Holben, I.V. Geogdzhayev and M.I. Mishchenko, 2003: Annual cycle of global distributions of aerosol optical depth from integration of MODIS retrievals and GOCART model simulations. J. Geophys. Res., 108, 10.1029/2002JD002717.

Penner, J.E., S.Y. Zhang, M. Chin, C.C. Chuang, J. Feichter, Y. Feng, I.V. Geogdzhayev, P. Ginoux, M. Herzog, A. Higurashi, D. Koch, C. Land, U. Lohmann, M. Mishchenko, T. Nakajima, G. Pitari, B. Soden, I. Tegen and L. Stowe, 2002: A comparison of model- and satellite-derived aerosol optical depth and reflectivity. J. Atmos. Sci., 59, 441-460.

Geogdzhayev, I.V., M.I. Mishchenko, W.B. Rossow, B. Cairns and A.A. Lacis, 2002: Global two-channel AVHRR retrievals of aerosol properties over the ocean for the period of NOAA-9 observations and preliminary retrievals using NOAA-7 and NOAA-11 data. J. Atmos. Sci., 59, 262-278.

Mishchenko, M., J. Penner and D. Anderson, 2002: Editorial: Global Aerosol Climatology Project, J. Atmos. Sci., 59, 249.

Kinne, S., B. Holben, T. Eck, A. Smirnov, O. Dubovik, I. Slutsker, D. Tanre, G. Zibozdi, U. Lohmann, S. Ghan, R. Easter, M. Chin, P. Ginoux, T. Takemura, I. Tegen, D. Koch, R. Kahn, E. Vermote, L. Stowe, O. Torres, M. Mishchenko, I. Geogdzhayev and A. Higurashi, 2001: How well do aerosol retrievals from satellites and representation in global circulation models match ground-based AERONET aerosol statistics? In Remote Sensing and Climate Modeling: Synergies and Limitations. M. Beniston and M.M. Verstraete, Eds., Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 103-158.

Haywood, J.M., P.N. Francis, I. Geogdzhayev, M. Mishchenko and R. Frey, 2001: Comparison of Saharan dust aerosol optical depth retrieved using aircraft mounted pyranometers and 2-channel AVHRR algorithms. Geophys. Res. Lett., 28, 2393-2396.