Abstract:Currently, wind speed profilers in common use have many problems, such as complex wiring, large volume, high power consumption, low measurement accuracy and automation level. They are also unable to achieve the real time recording and data processing. These bring many difficulties to study the variation law of near surface wind velocity, terrain roughness and its ability to resist wind erosion of degraded grassland. A thermal wind speed sensor which had small volume, low power consumption, high precision measurement was developed, and a near-surface velocity profiler with functions of automatic wind-direction recognition and wireless data transmission was designed, which can realize data automatic collection, wireless transmission and real-time data processing of environmental temperature, humidity, atmospheric pressure and near-surface wind speeds. Experiment results showed that the rotating start-up wind speed of the profiler was 3.7m/s, and the measurement range of the wind sensor whose maximum response time was no more than 3s was 0~16m/s with accuracy not less than 0.3m/s. It can work continuously more than 7h with one time charge, reflecting the change rule of the near-surface wind speed in height accurately with goodness of fitting of wind speed profiles above 0.9. The system can circularly scan up to six testing points, automatic collect and process wind speed data. The length of data packet was 35 bytes, the effective transmission distance can reach 500m and the data transfer time for six testing points was less than 10s under the conditions of 2.4kb/s transfer rate and maximum transmitting power. The system had advantages of low power consumption, easy to use, simple operation, automatic data acquisition, which can satisfy the needs of studying the change rule of near-surface wind speed.
