1.
The best relationship between analyzed variables (A,
AT, P) and soil moisture (mp, my, ms, was obtained for
the hillocks of soil micro-relief. The most significant
correlation was achieved between the thermal inertia
(TI) , calculated from Pratt's. et. al. (1981) model and
soil moisture of hillocks of micro-relief (my). The simi-
lar relationships between soil moisture and tempera-
ture of the soil were reported by Idso (1975) and Zieli-
nska (1984)
The regression coefficient for relationship between soil
moisture and thermal inertia is significant (R* =
0.7595), while between maximum diurnal temperature
differences is less (R = 0.6519) and between albedo
is the lowest (R® = 0.557).
Unexpectedly bad correlation was noticed for albedo
and soil moisture. This was probably caused by the
sampling method, which was not representative
enough for the variability of the observed albedo lev-
els. Another words, the number of the soils samples
for water content evaluation was insufficient to fit all
the albedo changes, especially because of the influ-
ence of the micro-relief of the soil surface. This was
clearly visible on the original panchromatic airborne
photos, (Fig.8). The problem, how to take the samples
that could be representative for an albedo and a tem-
perature distribution for the particularly image scale,
the different images resolution and proper mapping
time is still open.
Below are some examples of the input data: albedo A,
(Fig.4),maximum diurnal temperature differences AT,
(Fig.5).
oe
03-04
01-02 0.2 - 0.3
Fig. 4. Albedo of the test field B.
19 -20
i
16 - 17
17 - 18 18 - 19
Fig.5. Maximum temperature differences [ ? C], (field B).
The result of processing: thermal inertia P, and finally soil
moisture distribution for one of the test field (B) are pre-
sented on Fig.6 and Fig.7.
4.1. Topographic effect
Thermal inertia modeling needs calibration of remote
sensed images to albedo and temperature distribution.
The level of electromagnetic energy registered in remote
sensing techniques depends also on the terrain topogra.
phy. Variation of albedo and temperature might to be
caused by topographic effect. Correction method is
2600-2800 2800-3000 3000-3200 3200-3400
Fig.6. Thermal inertia [J / m? K s'" 1, (field B).
15-22 22 - 24 24 -26
Fig.7. Moisture of the soil surface
(hillocks of micro-relief) [%], (field B).
ERMO-POINT
p
MICRO-RELIEF
Fig. 8. Enlargement of the panchromatic photos (field B).
based on the assumption that the required radiation level
should be equal to the radiation, reflected from horizontal
surfaces. It means, that after transformation we should
obtain the radiation distribution similar as is observed for
the flat terrain. For correction of the topographical effect
the Bidirectional Reflection (or Radiation) Distribution
284
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
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