nm, it was difficult to distinguish 15% to 30% and 45 to 60%
leaf water content. In the first order differential spectrum, the
680 to 750 nm and 1125 to 1200 nm range clearly identified
the leaf water content at 60% to 75%, while the others could
not distinguish the leaf water content (Figure 4)
The
Alhagi pseudalhagi
reflectance curves revealed that
the reflectance spectra of
Alhagi pseudalhagi
with different
water contents showed no specific patterns. 45% to 60% of
the spectrum in the range of 375–700 nm was significantly
higher than the other content. The 750 to 1000 nm range
clearly identified the change in leaf water content at 15%
to 30%, 30% to 60%, and 60% to 75%, and the reflection
spectrum increased with the growth of
VWC
, except when the
content was 30% to 60%. The 1400 to 2500 nm range clearly
identified the content at 15% to 30% and 60% to 75%, while
the other spectral range could not distinguish the content. In
the first order differential spectrum, only the spectral range of
700 to 1000 nm could be distinguished from leaves with dif-
ferent water contents, the other spectral ranges could hardly
be distinguished (Figure 5).
The
Phragmites australis
reflectance curves revealed that
the absorption bands were similar to those of other desert
Figure 2. Reflectance and first order differential spectra of
Tamarix
under different leaf water contents.
Figure 3. Reflectance and first order differential spectra of
Haloxylon ammodendron
under different leaf water contents.
Figure 4. Reflectance and first order differential spectra of
Alhagi pseudalhagi
under different leaf water contents.
540
September 2018
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
