The general objectives of FIFE were to:
- Understand the biophysical processes controlling the fluxes of exchanges of radiation, moisture, and carbon dioxide between the land surface and the atmosphere.
- Develop and test remote-sensing methodologies for observing these processes at a pixel level.
- Understand how to scale the pixel-level information to regional scales commensurate with modeling of global processes.
Data Acquisition in FIFE
The data acquisition effort of FIFE can be divided into two broad categories: the monitoring effort and the Intensive Field Campaigns (IFCs).
- The monitoring effort, which operated more or less continuously through 1987, 1988, and 1989, consisted of the acquisition of AVHRR, Landsat, SPOT, and GOES satellite data; the continuous acquisition of relevant meteorological data from 16 automated meteorological stations within the site; the collection of gravimetric soil moisture surveys, streamflow data, and biometric measurements; and the observations of relevant atmospheric optical properties to study the effects of atmosphere on satellite remote-sensing images.
- The Intensive Field Campaigns (IFCs) had the specific objective of acquiring surface and airborne data in conjunction with the satellite overpasses to study the biophysical and energetic processes over spatial scales from millimeters to kilometers and temporal scales from seconds to an entire season. The IFCs required a large commitment of manpower and resources; thus, their combined duration during 1987 was only 57 days. The IFC periods targeted the critical phases of vegetative development (IFC-1 "greenup"; IFC-2 "peak greenness"; IFC-3 "dry-down"; IFC-4 "senescence"). In 1987 unusual weather conditions produced very similar conditions during the first three IFCs (wet soils and green vegetation) followed by a totally senescent vegetation cover and dry soil in IFC-4. During 1989 a 20-day (July 24-August 12) IFC was instituted to obtain the "dry down" missed during IFC-3.
Ground Measurements
Ground measurements were acquired at 32 sites within the Konza and were complemented by a number of other measurement sites (e.g., a dense network of 42 rain gauges in a watershed). A probability sample of sites were placed within strata representing the major spatial variation in soil depth, seasonally integrated incident solar radiation and management practice (e.g. grazing and burning).
Science Teams
Roughly 100 science investigators and support staff were working at the FIFE site during the IFCs. In addition to the selected investigators working in FIFE, there were two large groups of scientists and support staff conducting measurements on site. One group based at Kansas State University (Staff/KSU) carried out a wide range of measurements for the monitoring program and during IFCs. The Goddard Space Flight Center group (Staff/GSFC) supported experiment design, developed and operated the FIFE Information System (FIS) and provided administrative support.
Aircraft Overflights
As part of the experiment, three aircraft (NASA C-130, NASA Helicopter, and NOAA Aerocommander) took radiometric measurements using a variety of scanners, radiometers, and scatterometers operating over the visible, near infrared, thermal, and microwave wavelength intervals. Three other aircraft (Canadian Twin Otter, National Center for Atmospheric Research KingAir, and University of Wyoming KingAir) took flux measurements of heat, moisture, momentum, and carbon dioxide (Twin Otter only) fluxes over the site. These activities were closely coordinated with each other and with satellite overpasses. In all some 180 missions and over 400 flight hours of aircraft flight time were dedicated to data acquisition during FIFE.
Scaling Up Analysis (Micro to Macro)
One of the long-range objectives of FIFE is to make interdisciplinary connections between ground data, aircraft data, and finally satellite data. By making direct comparisons between ground data and corresponding aircraft data, scientists hope to learn about resolving the differences between the two data types. Once these differences -- how to get accurate "ground" data from aircraft overflights -- are understood, scientists can attempt to link aircraft data with satellite data. The eventual goal is to be able to accurately collect "ground" data from satellite overflights. This requires a great deal of new knowledge on how the atmosphere affects measurements and how small-scale trends can be detected within large-scale systems.
