Surface reflectance data is useful for the development of models for estimation of
vegetation water content and other vegetation parameters. Observations of surface
reflectance made concurrently with the biomass samples will be useful for the
development of these models and for upscaling this information to larger scales.
Furthermore, if the reflectance measurements are concurrent with satellite overpasses the
data can be used for the validation of satellite based reflectance estimates and
development of correction algorithms.
For CanEX-SM10, we are using an instrument developed by CROPSCAN
(http://www.cropscan.com). The CROPSCAN dual-detector instrument simultaneoulsly
measures sunlight and the amount of reflected light thus reducing the number of
calibrations are required. The CROPSCAN Multispectral Radiometer (MSR) has both
up-and-down-looking detectors for measurement of sunlight at different wavelengths.
The CROPSCAN multispectral radiometer systems consist of a radiometer, data logger
controller (DLC) or A/D converter, terminal, telescoping support pole, connecting cables
and operating software. The radiometer uses silicon or germanium photodiodes as light
transducers. Matched sets of the transducers with filters to select wavelength bands are
oriented in the radiometer housing to measure incident and reflected irradiation.
For CanEX-SM10 we will be using a MSR16R unit configured with the following bands.
The correspondence of these bands with available optical satellites is shown in
Figure 1.
Table 1. MSR-16 wavelength descriptions
ID
MSR16R-470U
MSR16R-470D
MSR16R-550U2
MSR16R-550D2
MSR16R-650U2
MSR16R-650D2
MSR16R-710U
MSR16R-710D
MSR16R-850U2
MSR16R-850D2
MSR16R-970U
MSR16R-970D
MSR16R-1240U
MSR16R-1240D
MSR16R-1640U
MSR16R-1640D
Centre Wavelength and Bandwidth
470 nm up sensor (10nm BW)
470 nm down sensor (10nm BW)
550 nm up sensor (40 nm BW)
550 nm down sensor (40 nm BW)
650 nm up sensor (40 nm BW)
650 nm down sensor (40 nm BW)
710 nm up sensor (12 nm BW)
710 nm down sensor (12 nm BW)
850 nm up sensor (40 nm BW)
850 nm down sensor (40 nm BW)
970 nm up sensor (10 nm BW
970 nm down sensor (10 nm BW)
1240 nm up sensor (12 nm BW)
1240 nm down sensor (12 nm BW)
1640 nm up sensor (16 nm BW)
1640 nm down sensor (16 nm BW)
Figure 1. Satellite measurements and correspondence with the MSR.
Sampling protocols.
1) Reflectance over Biomass Sample Site
Reflectance data will be collected for each vegetation sampling location (Figure 2)
just prior to removal using the following sampling scheme.
Making sure that the radiometer is well above the plant canopy; take a reading
every meter for 5 meters. Repeat, for a total of 5 replications located 1 meter or 1
row apart.
5 Meters
1 Meter
1 Meter/Row
Crop Scan
Sampling Point
Vegetation
Sampling Point
2) Field Transect
Each different land use type (Winter Wheat, pasture, etc.) will be characterized
by transect sampling. Reflectance will be collected at representative sites.
Reflectance will also be collected over water for calibration purposes. This
should be done to coincide with the satellite overpasses. The following sampling
scheme will be used for transect sampling (figure 3) :
MSR Field Data Sheet
Date and Time of Day:
Observer:
Data File Name:
General Field and Weather Conditions: