(click participants logo to enlarge)

Grassland PROVE (PROtotype Validation Exercise)

An EOS Coordinated Test of Validation Data Instrumentation and Sampling Strategies

May 20-30, 1997

USDA-ARS/LTER Jornada Experimental Range,
near Las Cruces, NM

Participants: MODIS, MISR, ASTER, USDA-ARS, LTER, AERONET, EOS IDS, ORNL DAAC, POLDER, CU/CCAR

See: Privette, J.L. and G.P. Asner (1999), The prototype validation exercise (PROVE) for EOS land and atmosphere products, Geoscience and Remote Sensing Symposium, IEEE IGARSS'99 Proceedings, 1:586-588.

and the PROVE Special Issue of Remote Sensing of Environment (est. publ.: ~March, 2000)
[LINE]

Prototype GOES Image Similar to Those Collected (30 min. res)
(Note that White Sands is the white blotch near the center of the image.)

	Information about the validation campaign
	Photo gallery of data collection

Jornada site in relation to the Chihuahuan Desert

Map, Courtesy of Barbara Nolen, New Mexico State University

Land Cover Map and Accociated Laser Altimeter data

Laser altimeter data for the shrubland (top), transitional (middle) and grassland (bottom) measurement plots at Jornada. The x and y scales vary greatly. Note sand dunes in the shrubland area appear as relatively broad cycles of several meters width in the altimeter data, but are not present at the other sites.

Map compliments of A. Nolen, laser data compliments of J. Ritchie.

Outline of Data Collected

PROVE data at the ORNL DAAC

Jornada Landsat TM data

Summary of Airborne Data, by Huete

Low-flying, aircraft based radiometers were utilized for optical characterization of 'top of the canopy' reflectances at La Jornada Experimental Range in New Mexico. The objective was to examine the usefulness of low-flying aircraft for MODIS validation of land products. Multiband radometers were flown at 100 m above ground level along transects encomapassing several land cover types within this semi-arid biome validation site. Pointable radiometers acquired data at nadir, 15, 30, and 45 degree viewing angles along the principal and orthogonal planes. The sequence of measurements involved two separate sun angle-based overflights coinciding with ground-based radiometric and biophysical measurements. The low flying set of radiometers did not require atmosphere correction and could rapidly cover a 3 km transect in less than a minute. The view and sun angle measurements were made to encompass the range of sun-target sensor conditions encountered with coarse resolution sensors over a compositing cycle. Reflectance and vegetation index variations attributed to sun and view angles were found to be much greater than those due to land cover differences. The optical differences among the land cover types were greater at the larger solar zenith angle. Satellite land products must be normalized for view and sun angle effects if biophysical and land cover differences in this semi-arid biome are to be detected. We found light aircraft radiometry to be very useful in land validation studies due to its rapidity, flexibility, consistency, and ability to measure at scales from meters to kilometers.