Study On Different Time Scales Relation Between Oriental Migratory Locust And Soil Moisture Content Based On Remote Sensing Technology

This paper deals with the order of different time scale relation between the content of soil moisture and the occurrence/outbreak of oriental migratory locust in the study area Huanghua county of Hebei province,the region in which has been severely suffering from the locust plague. Based on the information on the spatial distribution of the plague of locust using the data of locust density extracted based on the remote sensing technology in conjunction with the in situ data of soil samples taken in field as well as the ground measured remotely sensed data.In the study, the TM and ETM+data were used in monitoring the degree at which vegetation was suffering the damage by vegetation cover data before and after harm by locust respectively. Based on Landsat TM data, land surface temperature (LST) was derived by means of universal single-channel algorithm., plus MODIS data, which the LST products was used to acquired and build the LST-EVI feature space, and then to calculate the temperature vegetation dryness index (TVDI).Finally,this paper studies the inter-annual scale、seasonal time scale and locust outbreak period relationship between soil moisture contene and the locust outbreak.Through this study, four conclusions were as follow:This paper calculated TM/ETM+data of the locust density index in conjunction with the in situ data, then found that the monitoring results and field survey results are basically the same,the locust density index method can monitor the location and extent of locust outbreak effectively, on the May31,2002and June14,2010TM/ETM+image data.By constructing LST-EVI feature space to calculate temperature-vegetation dryness index. Analyzing the TVDI and observed soil moisture data, a linear curve was fitted to estimate volumetric soil moisture content in the depth of20cm for June14th,2010, in areas of natural surface of Huanghua City. TVDI is feasible for monitoring soil moisture content of the study area.In the three locust regions(nandagang、tengnandawa、huangzao) of Huanghua country, the lower soil moisture content in the later perion of locust hate hatching the higher degree of locust plague. In other words, the regions with lower soil moisture content are more suitable for locust occurrence.Most importantly, fall locust is at oviposition time during the periods which relates to the soil moisture condition. From September to October and March to April, when summer locust is at hatching, locust occurrs or outbreaks. Paper based on May31,2002and June14,2010TM/ETM+image data to study the relationship between soil moisture content and outbreak of oriental migratory locust in locust outbreak period, The temperature vegetation dryness index of locusts break year is greater than the normal year. Analyzing the TVDI and locust disturbance index, a linear curve was fitted to estimate locust disturbance index,the fitting accuracy is high,the environment of higher soil moisture content is suitable for locust to survive.