Study On Retrieval Of Soil Moisture Content In Huanghua Using Field Collected Thermal Infrared Data

Soil moisture content is indispensable factor for growing and development of plants, and a vital parameter which indicates soil drought, determines timing of spring cultivation, conduct the management of compensating irrigation and estimates crop yield. For Oriental migratory locust soil moisture content has direct impact to site selection for egg lay of the locusts, and their egg development and hatching. In addition, soil moisture content has indirect effects to the food taking and activities of both nymphs and adults of Oriental migratory locust.At present, the thermal IR remote sensing assisted methods for monitoring soil moisture content includes mainly thermal infrared method, thermal inertia method and temperature/vegetation index method. All these methods are models relying on analysis of the relationship between temperature difference and soil moisture content. Yet, as another vital parameter of thermal radiation, the relationship between emission rate and soil moisture content has been rarely studied.In this thesis, a suit of easy and useful way to measure the soil emissivity in the field was designed on the basis of radiant model calculation algorithm. By this approach, the emissive spectrum of different kinds of soil was measured in the field in Huanghua city in Hebei province. While analyzing these soil spectrums, it was found that the spectrum information is interfered seriously by the cover types on soil surface. The results show that for the flat and bare lands the soil emissivity in the 8-9.5μ m region increases gradually when soil moisture content increases.By comparing and analyzing the emissivity spectrums of two kinds of soil that contain different content of organic matter and collected from Huanghua city and Kunshan city, it was found that the emission of the long wavelength lobe of the quartz reststrahlen doublet of the soil, which contains a relatively small amount of organic matter, is approaching to those of shorter wavelength lobe. Moreover, in the range of 8.19-8.60μm, the emissive spectra of those soil containing a relatively small amount of organic matter increase rapidly, whereas those with large amount of...