DISCOVER is the acronym for Distributed Information Services: Climate/Ocean products and Visualizations for Earth Research, a NASA Earth Science MEaSUREs-funded project. The goal of the MEaSUREs program is to provide consistent data records for use in better understanding our Earth system. The emphasis is on linking multiple data sources to form a coherent time series.
Focus of this work
The major objective of the DISCOVER project is to provide highly accurate, multi-decadal geophysical products (measurements) derived from satellite microwave instruments. These products are suitable for some of the most demanding Earth research applications and are available via easy-to-use display and data access tools. Most of the products are generated in near real-time, so they also are suitable for some weather applications and field campaigns, however, the focus of our work is on climate analysis.
DISCOVER is a collaboration of Remote Sensing Systems (RSS), NASA Marshall Space Flight Center, and the University of Alabama in Huntsville (UAH). RSS, located in Santa Rosa, California, specializes in satellite microwave remote sensing. Information Technology researchers at UAH and the MSFC Earth Science Department jointly manage the Global Hydrology Resource Center (GHRC), a full-service data center. The GHRC is housed at theNational Space Science Technology Center (NSSTC) on the UAH campus. For the past 10 years, RSS and GHRC have provided the Earth science community with research-quality data products and services while leading the evolution of distributed, heterogeneous, and collaborative processing and distribution environments.
For more information on our UAH partners, see the DISCOVER web site at UAH.
The data products routinely provided by DISCOVER have a long history of development and refinement. Our state-of-the-art techniques employing physically-based retrieval procedures are a product of 35 years of refinements, beginning with early work on SeaSat in 1978.
The NOAA / NASA SSM/I Pathfinder project funded early work on SSM/I F08 and F10 data. From this project, we were first, in 1996, to provide ocean microwave products on our web page and ftp site. The SSM/I Pathfinder project pioneered the simultaneous retrieval of surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I observations.
The Passive Microwave - Earth Science Information Partnership (PM-ESIP) then began to provide the Earth science community with near real-time access to SSM/I and TMI ocean products, including sea surface temperature (SST), made possible by the low frequency (10.7 GHz) channels on TMI. This new microwave SST retrieval opened the door to a number of exciting research areas in oceanography, air-sea interaction, and hurricane forecasting.
NASA funding continued with the REASoN and MEaSUREs programs, allowing for a complete, consistently processed data set of ocean measurements from the entire series of DMSP SSM/I instruments: F08, F10, F11, F13, F14, and F15, the SSMIS available on F16, F17 and F18, TMI on TRMM, AMSR-E on Aqua, and WindSat on Coriolis. Without this continued funding, a uniformly processed radiometer measurements data set would not exist. All data are processed using the same radiative transfer model and Version-7 processing algorithms. The products are widely regarded as being exceptionally well calibrated and are essential in the production and validation of many other important data sets. For several scientists, the DISCOVER data are the basis on which they create a value-added reaserch product.
The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with intercalibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets suitable for climate study.
Over two decades of success at RSS and UAH are testament to the continual evolution of the research and data systems at these institutions. We are practicing scientists and information technologists who work directly with our Earth science colleagues to deliver the products, services and applications that the community requires and desires.
DISCOVER Earth Science Data Records
Earth System Data Records (ESDRs), including Climate Data Records (CDRs) are defined as a unified and coherent set of observations of a given parameter of the Earth system, which is optimized to meet specific requirements in addressing science questions. These data records are critical to understanding Earth System processes, to assessing variability, long-term trends, and change in the Earth System, and to providing input and validation for modeling efforts.
ESDRs support Earth science researchers by providing measurements that benefit from data coming from multiple missions spanning longer time periods. DISCOVER produces 5 ESDRs. These data sets have been carefully intercalibrated and consistently processed. The multi-decadal length along with high accuracy and multiple climate variables make the combined DISCOVER datasets particularly useful for answering NASA's "Big Question": "How is the global earth system changing?"
The DISCOVER ESDRs include:
|OP-ESDR||Ocean Products that are derived simultaneously from microwave radiometer measurements and delivered as a package of inter-related measurements, including:|
|MSST-ESDR||Microwave-derived through-cloud Sea Surface Temperatures|
|VW-ESDR||Sea surface Vector Winds derived from both scatterometer (active) and polarimetric radiometer (passive) microwave satellite measurements|
|TB-ESDR||Microwave radiometer Brightness Temperatures|
|AT-ESDR||Atmospheric Temperatures from microwave sounders. This data record includes temperatures for 5 different layers in the troposphere and lower stratosphere.|
The ESDRs are derived from observations by 33 satellites:
|14||Microwave sounders including MSU, AMSU to produce AT-ESDRs|
|16||Microwave imagers including SSM/I, TMI, AMSR-E, WindSat to produce TB-ESDRs, OP-ESDRs. and SST-ESDRs|
|3||Microwave scatterometers including NSCAT, QuikSCAT, ASCAT to produce VW-ESDRs|
Higher Level Data Products created as part of DISCOVER using the ESDRs listed above include:
- Multi-sensor Merged Fields for SST, wind speeds, water vapor, cloud water, and rain rate at temporal resolutions appropriate for the parameter characteristics.
- Passive Microwave Water Cycle data products containing monthly sea-surface evaporation, precipitation, latent heat flux, water vapor transport and divergence.
- 1-deg Merged Climate Products for wind and water vapor best suited for climate study and model comparison.
Special Application Products and Tools constructed from DISCOVER ESDRs for monitoring specific regional atmospheric and oceanic features include:
- wind jets, wind shadows and associated SST upwelling
- cold SST storm wakes and warm wakes caused by polar lows
- tropical cyclone wind and SST image archive
DISCOVER data are avialable from RSS and GHRC as well as other NASA DAACs. Be sure to read more details on the Missions and Measurements web pages. The most direct access to the DISCOVER data is from our data access table.
This work is pertinent to the following missions: SSMI / SSMIS, AMSRE, TMI, WindSat
This work is pertinent to the following measurements: wind, water vapor, cloud liquid water, rain rate, sea surface temperature