Generation of Extensive Moisture Content’s Map Using Weighted Moisture Values Over Multi-Surface Cover Types

The study utilized the Thermal Inertia method (TI) for soil surface moisture (θ) estimation, which is based
mainly on two sets of parameters. First, the spatial set, which includes the determination of satellite’s surface
Temperature (Ts) and the Vegetation Indices (VI). Second, the set of soil parameters, which includes the
determination of soil Field Capacity (FC) and the Permanent Wilting Point (PWP) as upper and lower boundaries of
the soil water capacity respectively. In this study, MODIS (Aqua/Terra) images were used for estimating the spatial
set (Ts and NDVI). Moreover, 3 meteorological stations at 3 different surface cover areas within the study area were
selected (Seberang Perak for agricultural land, UTP for multi-cover land and Sitiawan for urban area), then in-situ
measurements of FC, PWP, TS and θ were conducted over each station at the time of MODIS satellite overpass. In
order to overcome the atmospheric attenuation, the satellite’ Ts was rectified by the field measured Ts through
regression plots. After that, the satellite θ over the 3 different locations were generated and then validated using the
field measured θ. A good agreement was found between the actual and estimated θ, so that, the R
over the
agricultural area found to be 88%, over the area with multiple surface cover was 81% and over the urban area was
66%. After assuring the validity and the applicability of the used technique, a generalized θ map was generated
using weighting factors from three partitions of the surface cover in order to produce an accurate θ map that
considers the spectral disparity of variable surface covers within a single pixel.