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In this paper, the performance of the Coupled OceanвЂђAtmosphere Mesoscale Prediction System (COAMPSВ®) electromagnetic (EM) propagation forecast is assessed using numerous metrics such as forecast lengths, frequencies, ranges, and spatial resolutions. Moreover, it is suitable for solving the problem of the radio wave propagation in complex environment. Therefore, the variable step size on the PE can not only ensure the accuracy of calculation, but also reduce the memory and time required, which greatly improves the reliability and efficiency. The simulation results show that compared with the small step method, the variable step size method of the PE can reduce the horizontal sampling point by 55.9% and the calculation time by 69.6% when the accuracy is close to the small step method, and the variable step size method is more accurate than the fixed large size step method.

Finally, the electric wave characteristics of typical complex environment are advanced by the method. Secondly, the action mechanism of different environmental factors and the requirement of changing trend for step size are expounded through simulation, and the complex environment of PE application is classified according to the requirement of error. Firstly, the relationship between the error and the step size, the frequency and other factors of the SSFT(Split-Step Fourier Transform) solution in the standard atmosphere is deduced, and then the basic selection range of the step size is given for the variable step size method. In this paper, a variable step size method for the PE (Parabolic Equation) is proposed to solve the problem of low computational efficiency in the study of radio wave propagation at a large range of complex environments. The development of the nearвЂђsurface jet suggests that the MoninвЂђObukhov similarity theory (MOST) needs to be modified in representing marine atmospheric boundary layers over sea surface temperature fronts. Around the nearвЂђsurface jet, the magnitude of the negatively valued Richardson number significantly increases, indicating the dominance of buoyancy effects in the flow dynamics there. Analyses of the data obtained from the highвЂђresolution threeвЂђdimensional simulations revealed the dominant generation mechanisms of the nearвЂђsurface jet, which are the strong vertical mixing by the enhanced streamwise rolls and the mean downward motion. We then conducted direct numerical simulations and largeвЂђeddy simulations of atmospheric turbulence in the vicinity of the front and captured the nearвЂђsurface jet in simulations for the first time.

In a field experiment of atmospheric flows over the Gulf Stream, when the wind blew from the cold water to the warm water, we observed a nearвЂђsurface jet over the warm water. The interaction between atmospheres and oceans plays an important role in the global climate. MвЂђdeficits and curvature between the methods agree most often during periods of atmospheric stability. When all EDHs are below the transmitter, EDH variance is the primary contributor to propagation variance, but MвЂђdeficit and profile curvature variance play a secondary role.

MвЂђdeficit and curvature of the refractive profiles also influence propagation specifically in scenarios when EDH spans the transmitter.

Variation in EDH between the methods is greatest in stable environments. When the lowest EDH is small and EDH estimates span the transmitter height there are differences in physical regimes causing large propagation discrepanciesвЂ“for example, leakage into versus trapping within the duct. Differences in propagation are large when EDH estimates span the transmitter height and the lowest EDH across the methods is small, regardless of how much variation there is in EDH estimates.

#CAPSTER CO ID DRIVER#

Variations in evaporation duct height (EDH) are found to be a primary driver of differences in propagation between the estimated refractivity profiles, where location of the EDH relative to the transmitter changes the sensitivity of propagation predictions to EDH estimates. Propagation predictions are generated for refractive profiles from inвЂђsitu measurements, MoninвЂђObukov boundary layer similarity theory, and numerical weather prediction forecasts. This study investigates the differences in coвЂђlocated and synchronous refractivity estimations from the CASPERвЂђEast campaign. Evaporation ducts (ED) lead to anomalous propagation where characterization of EDs in the MASL occurs primarily through two methods: inвЂђsitu measurements and numerical modeling. Environmental predictions in the marine atmospheric surface layer (MASL) are imperative to optimize XвЂђband radar system performance in marine environments.

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