The large contrast between dielectric constant of liquid water (ε≈ 80) and dry soil (ε≈ 60) causes emissivity contrast of ≈ 0.4 for water and ≈ 0.95 for dry land 14.
VOLUMETRIX SOIL MOISTURE FREE
Free water has a dominant effect on the dielectric constant (the permittivity of a medium relative to that of free space) of the soil particles. As soil moisture increases, water is able to move more easily around the soil particles. Surface soil moisture is the water contained in the upper 10 cm of the soil profile which is a mixture of soil and air (both bound) and free water 18. The permittivity of a medium, like moist soil, characterizes electromagnetic wave propagation and attenuation in the medium 19. The principal of microwave remote sensing of soil moisture is based on the sensitivity of soil permittivity to the amount of liquid water. In depth knowledge of the interrelations between landscape components is critical for the outlining of the processes causing natural hazards. Soil moisture measurements over a large spatial extent (areal data rather than point data) are crucial for determination of the land surface water distribution and characterization of the interrelation processes occurring in the landscape structure. Soil moisture is a fundamental link between global water and carbon cycles and has major applications in predicting natural hazards such as droughts and floods 12. Soil moisture is a key variable used to describe water and energy exchanges at the land surface/atmosphere interface and one of the factors influencing the hydrological, meteorological, and ecological processes. These factors impose application of more effective methods as remote sensing that reduce the cost of studies and enable investigation of the larger and difficult to be accessed territories. The traditional methods for soil investigation require various field measurements which are expensive and time-consuming, especially in the countries with territories affected by soil degradation caused by drought.
The concept of sustainability demands in-depth knowledge of soil processes and the manner in which the soil reacts to environmental changes. They cause significant economic losses, particularly in the countries and regions which are subjected to increasing periods of drought. The main threats that lead to soil degradation are soil erosion, decline of the organic matter, pollution, soil sealing, and loss of biodiversity. On the other side, the integrity and condition of the soil resources are threatened by degradation processes induced by the climate changes and the industrial development. Particularly important is the role of the soil as a basis for human wellbeing, for life of animals and vegetation, as a biological and gene pool as well as a platform which preserves the historical and architectural heritage. Soil is a crucial component of the Earth’s ecosystem - it is a source of raw materials, a medium for plant growth, food and biomass production it is a means of water storage, and a modifier of Earth’s atmosphere. Investigated pilot areas which testifies that the RSMI is applicable in different territories. The generated results show very high level of correlation for the The index estimates the relative variation of volumetric soil moisture content in a given time period andĮnables determination of its change in relative values. In order to achieve this aim, Relative Soil Moisture Index (RSMI) based on Synthetic Aperture Radar (SAR) data wasĬalculated. To evaluate the relative soil moisture content in various soil differences and to trace its dynamics during growing season. Geosystems processes and application of innovative end effective methods for their investigation.
Mitigation of the negative effects of land degradation requires in-depth knowledge of the ongoing in the Due to the climate changes and industrial development, soil resources in these zones are prone toĭegradation. Soil is a dominant factor of the terrestrial geosystems in the dry sub-humid zones, particularly through its effect onīiomass production.