4种蒸发波导模型的对比与分析

蒸发波导模型常用来计算海上蒸发波导高度。为了认识当前不同蒸发波导模型之间的差异和方法,本文选取了目前使用广泛的4种蒸发波导模型(即P-J模型、Babin模型、NPS模型和伪折射率模型)进行对比和分析。本文首先探讨了在理想情况下它们对气象要素的敏感性,随后并利用我国南海近海大气层观测试验数据对比了这4种模型的蒸发波导高度计算结果。分析表明:相对湿度、风速和气—海温差的变化对4种模型的计算都有着较大的影响,特别是在不稳定层结状况下,4种模型计算得到的蒸发波导高度都随着相对湿度的增大而降低、随着风速的增大而增高。Babin模型和NPS模型计算的波导高度较为一致,伪折射率模型与前两种模型的计算结果存在差异,而P-J模型与其他3种模型存在较明显的偏差。基于南海气象数据的计算结果表明,不同蒸发波导模型在该海域蒸发波导的模拟结果略有不同,但4种模型计算得到的波导高度日变化变化趋势较为一致,波导高度极低值常出现在早晨,而极高值常出现在傍晚。

Comparison and analysis of four kinds of evaporation duct model

Evaporation duct model is often used to calculate the height of evaporation duct at sea. In order to understand the differences between and methods of different current evaporation duct models, the paper selects four evaporation duct models currently widely used (P-J model, Babin model, NPS model and pseudo-refractivity model) to make a comparison and analysis. This paper first discusses the sensitivity of the models to meteorological elements in the ideal situation, then uses the atmospheric observation experimental data of the offshore layer of South China Sea to compare the results of the evaporation duct height calculated by these four models. The analysis shows that the changes of relative humidity, wind speed and air-sea temperature difference all have large impacts on the calculation of the four kinds of models. In particular, under the unstable stratification condition, the heights of evaporation duct calculated by the four models all decrease with relative humidity and increase with wind speed. The duct height calculated by the Babin model and NPS model are consistent, the calculation result of pseudo-refractivity model and the results of the previous two models are different, and there is an obvious deviation between the result of P-J model and the results of the other three models. Calculation results based on the data of the South China Sea meteorological data indicates that simulation results of different evaporation duct model in the area are slightly different, but the diurnal variation trends of the duct heights calculated by the four models are consistent, the extremely low height values often occur in the morning, and the extremely high values often occur in the evening.