This paper presents a remote sensing approach for wheat drought monitoring and modeling

which based on the principles of soil water balance and energy balance. At first

the original soil water content （Wc） was obtained from the relationship of the soil moisture and in apparent thermal inertia which was established through the experiments conducted over nearly bare fields in the North China Plain. Secondly

the evapotranspiration （Et） of the wheat fields was estimated using the remotely sensed reflected solar radiation and surface temperatures extracted from the NOAA-AVHRR digital image as well as the meteorological data such as incoming solar radiation

air temperature

windspeed and vapor pressure from ground meteorological station. Then

the soil water content （Wt） in a particular period of time （say 10 day period） can be calculated using the equation of soil water balance. At last

A drought index model was developed by considering the water requirement of winter wheat and the available soil water content. This model has been proved to be effective in monitoring the wheat drought in a large area.