Development and Validation of an Evaporation Duct Model.Part Ⅱ:Evaluation and Improvement of Stability Functions  

作　　者：丁菊丽 费建芳 黄小刚 程小平 胡晓华 季亮 

机构地区：[1]Institute of Meteorology and Oceanography,PLA University of Science and Technology [2]Mailbox 5111 [3]Institute of Philosophy,PLA University of Science and Technology

出　　处：《Journal of Meteorological Research》2015年第3期482-495,共14页气象学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(41205004,41230421,and 41105065);China Meteorological Administration Special Public Welfare Research Fund(GYHY201106004)

摘　　要：This study aims to validate and improve the universal evaporation duct （UED） model through a further analysis of the stability function （ψ）. A large number of hydrometeorological observations obtained from a tower platform near Xisha Island of the South China Sea are employed, together with the latest variations inψ function. Applicability of different ψ functions for specific sea areas and stratification conditions is investigated based on three objective criteria. The results show that, under unstable conditions, ψfunction of Fairall et al. （1996） （i.e., Fairal196, similar for abbreviations of other function names） in general offers the best performance. However, strictly speaking, this holds true only for the stability （represented by bulk Richardson number RiB） range -2.6 ≤ RiB 〈 -0.1; when conditions become weakly unstable （-0.1 ≤ RiB 〈 --0.01）, Fairal196 offers the second best performance after Hu and Zhang （1992） （HYQ92）. Conversely, for near-neutral but slightly unstable conditions （-0.01≤ RiB 〈 0.0）, the effects of Edson04, Fairall03, Grachev00, and Fairal196 are similar, with Edson04 being the best function but offering only a weak advan- tage. Under stable conditions, HYQ92 is the optimal and offers a pronounced advantage, followed by the newly introduced SHEBA07 （by Grachev et al., 2007） function. Accordingly, the most favorable functions, i.e., Fairal196 and HYQ92, are incorporated into the UED model to obtain an improved version of the model. With the new functions, the mean root-mean-square （rms） errors of the modified refractivity （M）, 0-5-m M slope, 5-40-m M slope, and the rms errors of evaporation duct height （EDH） are reduced by 21.65%, 9.12%, 38.79%, and 59.06%, respectively, compared to the classical Naval Postgraduate School model.This study aims to validate and improve the universal evaporation duct （UED） model through a further analysis of the stability function （ψ）. A large number of hydrometeorological observations obtained from a tower platform near Xisha Island of the South China Sea are employed, together with the latest variations inψ function. Applicability of different ψ functions for specific sea areas and stratification conditions is investigated based on three objective criteria. The results show that, under unstable conditions, ψfunction of Fairall et al. （1996） （i.e., Fairal196, similar for abbreviations of other function names） in general offers the best performance. However, strictly speaking, this holds true only for the stability （represented by bulk Richardson number RiB） range -2.6 ≤ RiB 〈 -0.1; when conditions become weakly unstable （-0.1 ≤ RiB 〈 --0.01）, Fairal196 offers the second best performance after Hu and Zhang （1992） （HYQ92）. Conversely, for near-neutral but slightly unstable conditions （-0.01≤ RiB 〈 0.0）, the effects of Edson04, Fairall03, Grachev00, and Fairal196 are similar, with Edson04 being the best function but offering only a weak advan- tage. Under stable conditions, HYQ92 is the optimal and offers a pronounced advantage, followed by the newly introduced SHEBA07 （by Grachev et al., 2007） function. Accordingly, the most favorable functions, i.e., Fairal196 and HYQ92, are incorporated into the UED model to obtain an improved version of the model. With the new functions, the mean root-mean-square （rms） errors of the modified refractivity （M）, 0-5-m M slope, 5-40-m M slope, and the rms errors of evaporation duct height （EDH） are reduced by 21.65%, 9.12%, 38.79%, and 59.06%, respectively, compared to the classical Naval Postgraduate School model.

关 键 词：evaporation duct height stability function electromagnetic wave propagation 

分 类 号：P714.2[天文地球—海洋科学]