Modeling And Analysis Of Sea Surface Emissivity

Ocean surface as the interface between the ocean and atmosphere, it is an important research of marine research and development, salinity and temperature is an important physical parameters of the ocean,and is one of the important factors also determine the basic properties of the ocean. Whether the inversion temperature or salinity of ocean surface conditions must be considered. Wind affect ocean surface will appear rough sea and white crown phenomenon,all these factors affect the sea surface temperature and salinity retrieval accuracy. Ocean surface salinity affects the dielectric constant of seawater, thereby affecting the radiation characteristics of the ocean surface,then the ocean surface emissivity will change. Based on the above theoretical knowledge,researchers have begun to carry out research and experiments sea surface salinity and temperature long time ago, from permittivity of seawater analog to microwave radiometer measuring instruments improvements, from the land of the salt pond experiment to experiment aviation, even developed the current of satellite remote sensing inversion salinity and temperature. These numerous amendments inversion methods have encountered the problem of ocean surface emissivity.In this study, combining computer modeling techniques and experimental methods, research sea emissivity, reveals waves and wind effects on the ocean whitecaps emissivity impact mechanism, building a simulation model of natural sea emissivity. In this paper, based on the dielectric constant at low wind speed model, Fresnel reflectivity, emissivity model of calm seas and ocean surface roughness of the sea surface and building a emissivity model.In microwave remote sensing of ocean, Firstly calculate the dielectric constant of water by using frequency, salinity and temperature. Based on the dielectric constant Fresnel reflection can be obtained,it is 1- Fresnel reflectance obtained calm sea emissivity; Take the advantage of wind-induced sea surface brightness temperature increment get wind caused emissivity increment; superposition of the two above emissivity is the sea level emissivity, this method is an empirical model. AIEM sea surface emissivity model inversion is first performed to characterize the roughness of the sea, extract parameter of the rough sea,that is correlation length and RMS height, based AIEM model and using the parameters of rough sea derived ultimately roughness sea emissivity, analysis AIEM model’s feasibility. Results the difference between empirical models and AIEM model is very small, so AIEM model is suitable for marine applications of remote sensing inversion of sea surface emissivity.As the wind speed increases not only appears on the rough surface of the sea, the white crown phenomenon will appear, white crown is generated when the sea wind speed is 7m/s, it is wave breaking and alayer of very strong scattering source, will significantly change the dielectric constant of the ocean surface, thereby causing changes in ocean surface radiation characteristics.In this paper, The air as the background of the white layer is a layer of uniform distribution of spherical medium or water and gas of mixture complex structure.So it is the fir st that calculation of the effective dielectric constant of white layer when we do the inversion whitecaps emissivity.And then get the whitecaps emissivity by AIEM model.We can get the whole sea surface emissivity by whitecaps coverage when generating white sea.Also we can u se the model to validate the AIEM model.We verified the result is that two kinds of model dif ference is very small.So we can prove that AIEM model is applicable to arbitrary wave invers ion of sea surface emissivity.