Dy. Chen et al., SPATIAL-DISTRIBUTION AND PATTERN PERSISTENCE OF SURFACE SOIL-MOISTUREAND TEMPERATURE OVER PRAIRIE FROM REMOTE-SENSING, Remote sensing of environment, 61(3), 1997, pp. 347-360
Images remotely sensed aboard aircraft during FIFE, namely, PBMR (micr
owave) soil moisture and NS001 thermal infrared surface temperature, w
ere mapped on the same coordinate system covering the 20 km x 20 km ex
perimental site. For both kinds of image data, the frequency distribut
ions were close to symmetric, and the area averages compared reasonabl
y well with the ground based measurements. For any image on any given
day, the correlation between the remotely sensed values and collocated
ground based measurements over the area was usually high in the case
of NS001 surface temperature but low in the case of PBMR soil moisture
. On the other hand, fit ally given flux station the correlation betwe
en the PBMR and gravimetric soil moisture over all available clays was
usually high. The correlation pixel by pixel between images of PBMR o
n different days was generally high. The preservation of the spatial p
atterns of soil moisture was also evaluated by considering the correla
tion station by station between ground-based soil moisture measurement
s on different days; no persistence of spatial pattern was apparent cu
ring wet periods, but a definite pattern gradually established itself
toward the end of each drying episode. The spatial patterns of surface
temperature revealed by NS001 were not preserved even within a single
day. The cross-correlations among the two kinds of images and the veg
etation index NDVI were normally poor. This suggests that different ti
me scales were involved in the different processes of vegetation growt
h, and of the near-surface soil water and energy budgets. (C) Elsevier
Science Inc., 1997.