In 1987 NASA began field studies called FIFE, the First ISLSCP Field Experiment (ISLSCP = International Satellite Land Surface Climatology Project). This experiment required a grassland with large seasonal variances in soil moisture and living and dead plant biomass. In addition the project required a pre-existing research infrastructure and database. Konza Prairie and adjacent lands were therefore selected as the site for this experiment. The project is out of the Land Processes Branch, Earth Science and Applications Division. FIFE is scheduled for one intensive field season followed by two years of minor, additional field work in conjunction with data analysis and interpretation.
The major goal of this program is to provide an understanding of how the basic physical and biological processes that occur at the land/atmosphere interface may be observed using satellite remote sensing.
NASA’s Land Processes program, in cooperation with ISLSCP, has as its main objective the development and validation of techniques that may be applied to satellite observations of the radiation reflected and emitted from the earth to yield quantitative information concerning land surface climatological conditions and the use of these techniques in the scientific study of the land-atmosphere interaction. Currently, NASA is supporting research in two main areas:
- The evaluation of existing and newly collected data from satellites to determine their usefulness in detecting climate related fluctuations or human-induced changes in the land surface
- Development and validation of methods to convert satellite-observed radiances to variables related to land surface climatology
Briefly stated, the objective of the experiment is to obtain the necessary surface and atmospheric data to verify the extraction of land surface parameters from satellite radiance measurements. The parameters of interest include surface spectral reflectance properties (including albedo and the vegetation index), surface temperature, and components of the surface energy balance such as radiation budget components and the latent and sensible heat fluxes.
Twenty-nine proposals were initially funded in addition to basic support for data collection, storage, and retrieval. These proposals were of two types:
- Investigations providing additional measurements beyond the basic data set, and the interpretation of those data in the context of the combined data set
- Analysis or interpretation efforts using the combined data sets
Investigations have also been divided into working groups, which include the planetary boundary flux, surface energy flux, soil moisture and biology/spectral albedo teams in addition to data management, correction/calibration, and integration/synthesis groups.
Investigators associated with three LTER sites were funded as part of the FIFE study. These projects are involved with research on soil moisture, biology/spectral albedo, and synthesis topics:
- J. Tiedje and P. Groffman, Michigan State University -- Denitrification, nitrous oxide, carbon dioxide and soil moisture dynamics evaluated at the landscape level using remote sensing techniques
- D. Schimel, W. Parton, A. Woodmansee, Colorado State University -- Surface biophysical properties and trace gas exchange in the tallgrass prairie
- T. Seastedt, Kansas State University, and M. Dyer, Biosphere Research Inc. — The influence of grazing on land surface climatological variables.
This program presents the opportunity to link concepts and models of watersheds or landscapes with remotely sensed properties of the site. Specifically, mechanistic models of ecosystem phenomena (e.g., nitrogen cycling or net primary productivity) can be linked with GIS (geographical information systems) to provide robust biological interpretations to remotely sensed spatial variations. NASA will benefit from the LTER program because of the presence of
- Extensive pre-existing data on plant, soil, and water characteristics:
- A data management system capable of providing these data
- Considerable biological expertise to interpret these data
We obviously believe that biologically mediated processes will have a large influence in modifying regional climatic characteristics, and that knowledge of these interactions will be useful when considering future measurements or models of regional and global climatic change. In turn, the LTER site and investigators will benefit because of
- Additional measurements on climate and microclimate, plant, soil, and water characteristics
- Training in remote sensing procedures
- A state-of-the-art assessment of the value of remote sensing in measuring and interpreting biological phenomena
The NASA-LTER interaction presents an opportunity for real advances in the areas of scaling, landscape ecology, ecological modeling, and innovative technologies designed to measure and/or integrate large-scale spatial variation in ecological processes. The program is both a preliminary experiment and a prototype for subsequent programs interested in landscape ecology and regional and global biological monitoring.
Portions of this article were taken from The FIFE Handbook by Piers J. Sellers and others. Additional text was provided by T.R. Seastedt of the Konza Prairie LTER Site (Division of Biology, Kansas State University, Manhattan, KS 66506).