| Co-Investigator(Kenkyū-buntansha) |
FUJINO Kazuo I.L.T.S., Hokkaido University, Professor, 低温科学研究所, 教授 (50001649)
MOTOI Kazushi Hokkaido Institute of Technology, Assistant, 工学部, 助手 (60118148)
SASAKI Masami Hokkaido Institute of Technology, Lecturer, 工学部, 講師 (70196179)
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| Research Abstract |
The FM-CW radar has the characteristics of detecting reflection from the interfaces within the medium, and enable its to obtain the record of a profile through the medium. Using the microwave frequency, we have developed an FM-CW radar system for measuring snowpack properties and for adapting with field measurement over a long time.
In our system, the microwave frequency was swept linearly over the range, 6-12 GHz, in 10 ms. The microwave was emitted toward the snowpack surface, and reflected from various interfaces within the snowpack. The frequencies in the received signals were displayed on a monitor of spectrum analyzer. At the same time, the received signals in time domain transferred to the CPU for processing and storing. Then, the data collected in time domain were transformed to the frequency domain.
Using the frequencies corresponding to the interfaces within snowpack, the snowpack properties such as dielectric constant, density, water equivalent and so forth were calculated. The changes of the internal structure within snowpack were composed from the serial data obtained by the system, and shown in the images displayed on the CRT. And also, several interpretations of the images were given for 1) melting snowpack, 2) dry snowpack, 3) ice plate in the snowpack and 4) forming process of strata within snowpack.
The Marine Observation Satellite (MOS) - 1 is the first Japanese earth observation satellite launched in 1987. In 1988, using our FM-CW system, a series measurement of snowpack parameters were carried out for obtaining the ground truth data in Sapporo, synchronizing with the MOS-1 airborne verification program.
The FM-CW microwave system is fairly effective for remotely measuring snowpack properties and internal structure of snowpacks, and also has an availability for evaluation the data related snowpack parameters which were obtained by a passive microwave sensor mounting on the orbital satellite, such as MOS-1.
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