Study On Monitoring Soil Moisture Of Large Region With MODIS Data

Content : Soil moisture is one of the control factors in crop growth. Monitoring lager region soil moisture is also a difficult problem in academic. In this paper, first we learn back the foundational conception of drought and drought index of routine and in common use index to classify drought. The traditional method of monitoring soil moisture can only collect the information of a point or a small region. These information which they need to know impersonal, real-time, and larger region soil moisture can't meet requirement of the science research and the government. But remote sensing with ground survey can meet this requirement. In this paper introduce the common method which monitoring soil moisture with remote sensing and its research evolvement. The main methods of remote sensing monitoring are thermal inertia, microwave, thermal infrared ray, anomaly vegetation index, vegetation supply water index, crop water stress index, green index. The common information remote sensing resources are the AVHHRR, but now we have MODIS better information of remote sensing than AVHRR. So we must make a research at MODIS to monitor soil moisture. I haven't seen other people do it from the literature.In this paper I have made a research in monitor soil moisture use MODIS data. Thermal inertia is fit to monitoring the period which the ground is bareness and the ground is covered by crop which is in early stage of growth. Vegetation supply water index is fit to monitoring the period which the ground is covered by crop. In this paper have calculate the thermal inertia and vegetation supply water index and then to use the soil moisture data which the weather station have measured to calculate the reliability and the precision. It gets the following conclusions. It's feasibly to use the MODIS data to monitoring soil moisture. The best depth of thermal inertia monitoring soil moisture is 20cm, and not useful for higher depth than 20cm. Vegetation supply water index and also fit to monitor surface soil layer, and the precision isn't high. There are many factors to influence the precision of monitoring soil moisture, so we should make a deeply research to make a steady model to fit more conditions. At last we conclude how to make a better precision of monitoring soil moisture and what should we take care.