| The atmospheric enviorenment has become an important field of propagation of radio waves with the technique of electromagnetic wave propagation wildly used recently, especially in the changeful troposphere. The atmospheric duct is a kind of abnormal structure in the troposphere air. Because of radio wave anomalous propagation along the atmospheric ducts, the problems of the co-channel interference are more complicate for communication systems with the results of intersystem interference and the formation of other system. Besides those, for surveillance equipments such as radar they can produce radar holes or the extensions of detect range. Howere, the occurrence of the atmospheric duct is stochastic and lies on the characters of the troposphere air process absolutely. If the changeful law of the atmospheric duct is drawn and its occurring time and extension are estimated and forecasted, the surveillance equipments can exert all their powers to work well, based on frequency, launching elevation and so on. So based on the real data from the atmosphere and sea, atmospheric ducts can be analysed, estimated and forecasted, which has great theoretical significance and is of great value espically to military when effects of atmospheric duct on propagation of radio waves and functions of surveillance equipments are estimated. The meteorological ocean data and sounding data, are very scarce by traditional measurements such as buoys and vessels in the marine- atmospheric environment, especially over the wide ocean, which can not meet present needs. What's more, the diurnal marine atomaspheric boundary layer changes slowly on the ocean, the atmospheric ducts last long and are stable. Many countries are interested with them. China is one of the greatest countries of the ocean and owns long coastline so the researches of tropospheric duct in coastal waters, especialy in marine atmospheric boundary layer are being developed urgently.The researches are conducted according to the evolution mechanisms and duct types separately. The most interior current studies are concentrated on single sounding site duct conditions. However more attentions are paid on the extent of existing duct in practice. So the paper founds coupling models between satellite remote data and evaporation duct height, studies retrieval arithmetic and estimates models using the sea surface temperature, wind speed, air temperature, relative humidity near the sea retrieved from the satellite remote data. Besides those, evaporation duct asymmetric distributions are analyzed with the above method firstly. Then the Pennsylvannia State Universtity/National Center for Atmospheric Research Fifth Generation Mesoscale Model (MM5) is used to simulate the elevated ducts and surface ducts and analyze the evolution mechanisms. Simulation of atmospheric duct with the MM5 is studied system systemically which is filled up the gap in interior Simulation of atmospheric duct.The conclusions derived from these researches are following:(1)Two methods based on the multiparameter neural network and P-J model are proposed to retrieve the evaporation duct from the AMSR-E data. One is to retrieve the sea surface parameters and then calculate the evaporation duct, the other is to retrieve the evaporation duct directly. The correlation coefficients between estimated evaporation duct from AMSR-E data and calculated by P-J model from buoy measurements parameters are all about 0.82 and root-mean-square errors of them are 2.64 meters and 1.89 meters respectively. So the first method is better than the second one. The evaporation ducts of South China Sea are retrieved from AMSR-E data using the later method and evaporation duct asymmetric distributions are analyzed from the retrieved results.(2)The paper takes example for the atmospheric ducts occurred in Yellow sea from from Jun 2 to Jun 3 of 2005 and designs several numerical tests to simulate the the atmospheric ducts for 24 hours with MM5 model, including whether or not using data assimilation with routine sounding and ground data and how much levels the models used etc. Some conclusions are inducted through the study: first, grid nudging with the rountine observed data in the MM5 simulation of atmospheric duct affects less over the sea than the land;Second,how much of sigma levels have great influence on simulation of atmospheric duct and the MM5 simulation with more sigma levels depicting the atmospheric ducts are reasonable; Last, multiple nests are allowed on a given level of nesting domain in the MM5 model.The mother domain has the ability enough to simulate the atmospheric duct over the sea than the sub-domain.(3) Two numerical simulations of atmospheric duct process in the Yellow Sea is produced with MM5 atmospheric model based on NCEP reanalyzed data. One is from Jun 2 to Jun 4 of 2005 and the other one is from May 10 to May 11 resulted from No 2 typhoon'RAMMASUN'in 2008. The simulated results corresponding to upper Observation stations are consistent with the profiles from the sounding balloons basically, but the simulated duct parameters such as duct strength are less than those from sounding balloons generally. The duct parameters evolution processes are given and synoptic processes are analyzed. The results show that the temporal and spacial evolutions of the simulated duct parameters are reasonable and authentic and MM5 model can simulate the evolution of atmospheric ducts and describe the characters of them.
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