PALSAR_Radiometric_Terrain_Corrected_low_res

ALOS PALSAR Level 1.0

The goal of the Alaska Advanced Very High Resolution Radiometer (AVHRR) project is to compile a time series data set of calibrated, georegistered daily observations and twice-monthly maximum normalized difference vegetation index (NDVI) composites for Alaska's annual growing season (April-October). This data set has applications for environmental monitoring and for assessing impacts of global climate change. An Alaska AVHRR data set is comprised of twice-monthly maximum NDVI composites of daily satellite observations. The NDVI composites contain 10 bands of information, including AVHRR channels 1-5, maximum NDVI, satellite zenith, solar zenith, and relative azimuth. The daily observations, bands 1-9, have been calibrated to reflectance, scaled to byte data, and geometrically registered to the Albers Equal-Area Conic map projection. The 10th band is a pointer to identify the date and scene ID of the source daily observation (scene) for each pixel.

The compositing process required each daily overpass to be registered to a common map projection to ensure that from day to day each 1-km pixel represented the exact same ground location. The Albers Equal-Area Conic map projection provides for equal area representation, which enables easy measurement of area throughout the data. Each daily observation for the growing season was registered to a base image using image-to-image correlation.

The NDVI data are calculated from the calibrated, geometrically registered daily observations. The NDVI value is the difference between near-infrared (AVHRR Channel 2) and visible (AVHRR Channel 1) reflectance values divided by total measured reflectance. A maximum NDVI compositing process was used on the daily observations. The NDVI is examined pixel by pixel for each observation during the compositing period to determine and retain the maximum value. Often when displaying data covering large areas, such as AVHRR data, it is beneficial to include an overlay of either familiar linework for reflectance or polygon data sets to derive statistical summaries of regions. All of the linework images represent lines in raster format as 1-km cells and the strata are represented as polygons registered to the AVHRR data. The linework and polygon data sets include international boundaries, Alaskan roads with the Trans-Alaska Pipeline, and a raster polygon mask of the State.

The aerial photography inventoried by the Pilot Land Data System
(PLDS) at NASA AMES Research Center has been transferred to the USGS
EROS Data Center. The photos were obtained from cameras mounted on
high and medium altitude aircraft based at the NASA Ames Research
Center. Several cameras with varying focal lengths, lenses and film
formats are used, but the Wild RC-10 camera with a focal length of 152
millimeters and a 9 by 9 inch film format is most common. The positive
transparencies are typically used for ancillary ground checks in
conjunctions with digital processing for the same sites. The aircraft
flights, specifically requested by scientists performing approved
research, often simultaneously collect data using other sensors on
board (e.g. Thematic Mapper Simulators (TMS) and Thermal Infrared
Multispectral Scanners). High altitude color infrared photography is
used regularly by government agencies for such applications as crop
yield forecasting, timber inventory and defoliation assessment, water
resource management, land use surveys, water pollution monitoring, and
natural disaster assessment.

To order, specify the latitude and longitude of interest. You will then be
given a list of photos available for that location. In some cases, "flight
books" are available at EDC that describe the nature of the mission during
which the photos were taken and other attribute information. The customer
service personnel have access to these books for those photo sets for which
the books exist.

TES focuses on the troposphere, the layer of atmosphere that stretches from the ground to the altitude at which airplanes fly. With very high spectral resolution, TES can distinguish concentrations of gases at different altitudes, a key factor in understanding their behavior and impact. It's the first orbiting instrument able to do this with ozone, a very important chemical with regard to both global warming and air pollution.
The primary location for obtaining TES data is NASA's Warehouse Inventory Search Tool (WIST). The TES Data Sets page at NASA Langley Research Center (LaRC ASDC) provides access to software read tools, a Data Pool, and supporting documentation.

The GCMD database holds more than 30,000 descriptions of Earth science data sets and services covering all aspects of Earth and environmental sciences. The mission of the GCMD is to (1) Assist the scientific community in the discovery of Earth science data, related services, and ancillary information (platforms, instruments, projects, data centers/service providers); and (2) Provide discovery/collection-level metadata of Earth science resources and provide scientists a comprehensive and high quality database to reduce overall expenditures for scientific data collection and dissemination.

The CEOS IDN is an international effort developed to assist researchers in locating information on available datasets and services. The directory is sponsored as a service to the Earth science community.