Data Set Overview : This data set was acquired during GRSFE with the Daedalus AA440 spectrafax instrument. The data set consists of over 500 data files. The values stored in each data file are raw instrument counts, which are proportional to radiance. The purpose of these measurements was to provide ground calibration for AVIRIS and ASAS data.  A number of reflectance measurements were made to estimate the average reflectance of an area about 50 by 50 meters in size (i.e., the size of several AVIRIS pixels). Measurements were made at Lunar Lake to characterize the reflectance of the spectral components at each GRSFE modeling site.  The detached PDS labels for each spectrum contain a brief description of the site and purpose of the measurement. The data set was acquired during the July 1989 field campaign.  The reflectance of a bright and dark target area was characterized with the Daedalus spectrafax instrument at Kelso Dunes and the Cima Volcanic Field. The reflectance of Trail Canyon Fan, the salt deposit at the Devil's Golf Course, Death Valley Dunes, and the tephra deposit at Ubehebe Crater were also characterized with the instrument.  At each site measurements were made along 2 or 3 traverses. The reflectance of the natural surface was measured at points along the traverse. Samples were spaced about 3 meters apart with 10 to 12 samples per traverse. The spectralon calibration standard was generally measured at the beginning and end of each traverse. Additional samples of vegetation and other significant components of the site (e.g., coated rocks) were also measured.  Nearly 200 measurements were made at Lunar Lake for the purpose of calibrating the airborne GRSFE data, characterizing the reflectance of end-member materials in the modeling sites, and comparing reflectance spectra made by the field spectrometers used during GRSFE. The procedure used to collect data for the calibration of airborne data was the same as describe in the previous paragraph. Data for this purpose were collected at the playa, disturbed playa, and cobble sites at about 8:00am, 9:30am, and 11:00am (local time).  Measurements were also made for characterizing spectral end-members at the disturbed playa and the cobble site. The smooth playa site was not characterized because the instrument batteries wore down. However, the playa site is very uniform and there should be sufficient data from the airborne calibration experiment to characterized the spectral components of this playa. There are no Daedalus spectrafax measurements of the lava flow site, again because the instrument batteries wore down before visiting that site. Several measurements were made at Lunar Lake to compare spectra from the Daedalus spectrafax and SIRIS instruments. In this experiment, both spectrometers measured the same calibration standard and then measured the same sample of undisturbed and disturbed playa, along with a large basalt cobble.  Processing Level Id : 3 Software Flag : N Processing Start Time : 1989-07-20T00:00:00.000 Processing Stop Time : 1991-05-28T00:00:00.000   Parameters :  Data Set Parameter 'RADIANCE' ----------------------------- Radiance is the amount of energy per time per projected area per steradian.  Data Set Parameter Name : RADIANCE Data Set Parameter Unit : N/A Sampling Parameter Name : WAVELENGTH Sampling Parameter Unit : NANOMETER Minimum Sampling Parameter : 450 Maximum Sampling Parameter : 2400 Sampling Parameter Resolution : 5.4 Sampling Parameter Interval : 5.4 Minimum Available Sampling Int : N/A Noise Level : UNK   Source Instrument Parameters : Instrument Host ID : FEXP Data Set Parameter Name : RADIANCE Instrument Parameter Name : RADIANCE Important Instrument Parameters : 1   Measurement Information :  Atmospheric Conditions ---------------------- Not Applicable   Source ------ Reflected sunlight provides the source of the energy detected by the spectrometer.   Calibration Standard -------------------- Spectralon calibration target used.   Wavelength Calibration ---------------------- Not Applicable   Processing :  Processing History ------------------ Source Data Set ID : N/A Software : UNK Product Data Set ID : FEXP-E-DAED-3-RDR-SPECTRUM-V1.0

Overview : Measurements made with the Daedalus spectrafax instrument during GRSFE were hand held with the instrument height only approximately fixed. Thus, there can be a small difference in the height used to measure the calibration standard and a given sample. Such a height difference will produce a systematic error in the absolute reflectance value. Each centimeter difference in height will produce about a 2% change in reflectance.  During GRSFE the instrument showed two operating problems. One problem was the result of saturation in the electronics that affected channels in the wavelength range of about 0.73 to 0.97 micrometers. This problem can be readily seen in the spectra of the calibration standard. The radiance values in the affected wavelength range are approximately constant and well below the values expected for these wavelengths. Data in this wavelength range should be considered bad. The second problem involved the filter wheel not properly rotating during data collection. Measurements with the filter wheel problem have been removed from the GRSFE archive.