金塔绿洲农田下垫面温湿度的非相似性分析  

Dissimilarity Analysis between Scalars over Farmland Surface in Jinta Oasis

作　　者：张珊[1,2] 张宇[1] 王少影[1] 尚伦宇[1] 苏有琦 

机构地区：[1]中国科学院寒区旱区环境与工程研究所寒旱区陆面过程与气候变化重点实验室,兰州730000 [2]中国科学院大学,北京100049

出　　处：《高原气象》2016年第3期633-642,共10页Plateau Meteorology

基　　金：国家自然科学基金项目(41275016;9137106);公益性行业(气象)科研专项(GYHY201306020)

摘　　要：利用2005年金塔绿洲的湍流资料分析了金塔绿洲农田下垫面上温度和湿度的非相似性。结果表明,低层风速较小和高层风速介于2~4m·s^(-1)时,温度和湿度标量的相似性较大,且温湿度的相似性随稳定度向近中性条件偏移而减小;R_(Tq)(n)和λ_((n))分别在频率域10^(-2)<n<10^(-1)和10^(-1)<n<10~0上近似为常数,且随着|r_(Tq)|的减小,R_(Tq)(n)所对应的谱峰频率逐渐减小,相对输送效率λ_n也减小,即水汽的输送效率逐渐增大,这是由于绿洲—沙漠的热平流抑制热量输送的缘故。Monin-Obukhov（M-O） similarity theory is an important theoretical basis of the study of the atmospheric surface layer turbulence.Since the surface is always heterogeneous at different scales and in different degrees,temperature（T） is not similar to humidity（q）.In order to investigate the dissimilarity of temperature and humidity at different scales and to further understand the turbulent transport process above Jinta Oasis farmland,the data for three heights（3.33,8.41,16.60 m） in sunny day from the ＂The Oasis System Energy and Water Cycle Field Experiment＂ over Jinta Oasis farmland was used,which was conducted from 23 May to 18 June in 2005.Firstly,the correlation coefficient of temperature and humidity for every 30-min runs was calculated.Secondly,the frequency distributions of ｜ r_（Tq） ｜ in different wind directions and different wind velocity,and the probability distributions of stability with different correlation coefficients for three heights in daytime were analyzed.Thirdly,the spectrum of the correlation coefficient and relative transfer efficiency with Fourier transform under six kinds of correlation coefficient cases（r_（Tq） 0.6,0.3 r_（Tq） 0.6,0 r_（Tq） 0.3,-0.6,-0.6 rTq -0.3,-0.3r_（Tq）0） and three kinds of stability conditions（unstable ζ-0.05,near-neutral-0.05ζ0.05,stable ζ0.05）were analyzed in the frequency domain.The results show that the scalar similarity is larger with the lower wind speed at the low level and with the wind speed is between 2^-4 m·s^（-1） at the top level.With the stability closing to near-neutral conditions,the scalar similarity is decreasing.R_（Tq）（n）and λ_n is approximately to a constant in the frequency domain 10^（-2）n10^（-1） and 10^（-1）n10~0,respectively.With the ｜r_（Tq）｜ decreasing,the corresponding peak frequency of R_（Tq）（n） is decreasing,and the relative transfer efficiency is also decreasing,i.e.,the transfer efficiency of water vapor is increasing,which are caused by the inhibiti

关 键 词：金塔绿洲 标量相似性 相关系数 相对输送效率 

分 类 号：P404[天文地球—大气科学及气象学]