近海层大气湍流通量系数研究

根据１９９４年９月１８～３０日南沙群岛海域渚碧礁的近海面大气湍流观测实验资料,分别计算了该海域光滑海面和粗糙海面上的空气动力粗糙度（ｚ０ ）、中性曳力系数（ Ｃ Ｄ Ｎ）。利用 Ｂｕｔｓａｅｒｔ 的假定,推导了求取标量粗糙度（ｚ Ｔ、ｚ Ｑ）、整体输送系数（感热交换系数 Ｃ Ｈ Ｎ、水汽交换系数 Ｃ Ｅ Ｎ ）的一组公式。在此基础上,分别计算和分析了该海域光滑海面和粗糙海面上空气动力粗糙度（ｚ０ ）、标量粗糙度（ｚ Ｔ、ｚ Ｑ ）、中性曳力系数（ Ｃ Ｄ Ｎ）、整体输送系数（感热交换系数 Ｃ Ｈ Ｎ、水汽交换系数 Ｃ Ｅ Ｎ）及其关于水平风速分量的分布,并得到了一些有益的结论。     

青藏高原总体输送系数的特征

利用中日亚洲季风机制合作研究计划设在西藏的 4个自动气象站（AWS）获得的5a多（199年7月～1998年12月）时次密集、观测连续的近地层梯度资料,以最小二乘法确定出相应站点各季节的地表粗糙度,并应用廓线-通量法计算了4站逐日的总体输送系数,分析了其随时间的变化特征。结果表明:青藏高原动量输送系数的多年平均值为3.53×10-3～4.99×10-3,热量输送系数为4.67×10-3～6.73×10-3,并且两种输送系数都存在明显的日变化和季节变化,部分站点还存在较明显的年际变化。另外,还讨论了总体输送系数与近地层大气层结稳定度、地表粗糙度以及地面风速等因子的关系,初步建立了可用常规气象站地面观测资料计算青藏高原总体输送系数的拟合公式。     

AN EVALUATION OF DISPERSION COEFFICIENTS FOR USE IN AIR QUALITY MODELS

Standard deviations of concentration in horizontal andvertical directions i.e. y andz have been estimated by using fivedifferent schemes based on empirical(due to Pasquill and Briggs)schemes and sophisticated methods(due to Irwin, Draxler, Taylor, Hanna et al.). The fiveschemes are discussed atlength. The purpose of this study is to make use ofmeteorological observations whichare routinely available, to test all the above methods andintercompare the resultswith one another and observations so that the sensitivityof each schemeunder various atmospheric stability conditions could beassessed. It has beenfound that the existing schemes are good enough to providereasonable estimates ofdispersion coefficient (y) during highly unstableconditions (Pasquill stability classes A and B). However, thesame is not true for the case when the stability increasesfrom C to F and turbulencedecreases, specifically during stable atmospheric conditions,when the observedvalues were found to be much higher than all the existingschemes. This suggests thatwhile we continue to use the current methods of estimatingthe dispersion parameters,a rigorous search is required for methods which give predictionswhich are close-to-realityduring such conditions which are represented by lowlevels (in terms of magnitude)of atmospheric turbulence leading to higher levelsof pollution.As one of the sophisticated methods requiresthe use of v and w (standard deviationsof wind velocity fluctuation in y and z directions),these have been estimated andvalidated with observed data (field experiments conductedby EPRI at Kincaid).Statistical evaluation of v and wbased on performance measures indicate a goodperformance of the parameterisations adopted in thisstudy. In the case of w duringunstable conditions a comparison of three differentschemes with observations is made.     

利用测温声雷达回波图估算大气扩散的一种参数化方法

本文提出了一种基于湍流扩散统计理论的利用声雷达回波图估算大气扩散参数的新方法。这种新方法,仅需要从声雷达回波图上读出边界层结构的信息并取得常规地面测风资料,即可利用参数化公式进行计算,不需进行Pasquill稳定度分类。 所应用的参数化公式用外场观测资料进行了检验,表明公式计算结果与观测值比较符合。这种方法计算得到的扩散参数也与P-G扩散曲线进行了比较。     

不同下垫面的粗糙度和中性曳力系数研究

根据１９９４年９月１８－３０日南沙海域近海经层大气湍流观测资料和黑河实验（ＨＥＩＦＥ）１９９０年８月１～２４日的微气象站及１９９８年６月ＧＡＭＥ／Ｔｉｂｅｔ的观测资料,利用Ｂｒｕｔｓａｅｒｔ的假定和Ｍｏｎｉｎ－Ｏｂｕｋｈｏｖ相似理论的推广和延伸,分别分析和计算了该海域近海层光滑海面粗糙海面上空气动力粗糙度（ｚ０）、标量粗糙度（ｚｒ,ｚｑ）、中性曳力系数（ＣＤＮ）、整体输送系数（感热交换系数ＣＨＮ、     

臭氧吸收参数数据库精度检验和验证

利用国际权威期刊上发表的臭氧吸收截面观测数据,检验和验证了现有的紫外正演模式TOMRAD臭氧吸收参数数据库。结果表明,在Hartley臭氧吸收带上,观测数据与数据库参数吻合状况很好;而在Huggins臭氧吸收带上,观测数据与数据库参数在部分波长上存在较大偏差,某些波长上的偏差超过50%。鉴于此,FY-3紫外臭氧探测仪资料处理计算中,选取臭氧吸收参数,必须特别慎重。     

黑河地区地面阻曳系数的估算及其影响的数值试验

本文利用黑河地区在气相互作用观测试验期间戈壁１２天、沙漠６天逐时塔站观测资料以及胡隐樵等的组合法所获得的感热、摩擦速度等，用倒算法估算了黑河地区地面通量的阻曳系数值，最后根据所估算的阻曳系数值，进行了边界层过程对短期天气预报影响的数值试验。结果表明，黑河地区的阻曳系数存在较明显的日变化；所获得的黑河地区戈壁及沙漠下垫面的日平均阻曳系数估算值大体是合理的；边界层过程仅对个别敏感区或盛行局地影响的短期天气过程有较明显的影响     

ATMOSPHERIC WAVE AND ITS PHYSICAL ESSENCE AS REVEALED BY CHANGED CORRELATION COEFFICIENTS AND CORRELATION FIELD

Formal change is made of the correlation coefficient(COCOEF)expression,leading to a new formula consisting ofFourier spectral coefficients that indicates a direct connection between the new form and atmospheric dynamicequations,thus resulting in a dynamic equation represented by COCOEF,which is meaningful in exploring a large-scaledynamic process in terms of the correlation field because the connection revealed by the field can have dynamic explana-tion with the aid of the new formula.     

车贝雪夫系数与我国温度、降水关系的初步探讨

本文用车贝雪夫多项式分解了15—65°N、75—155°E范围内,1954—1975年逐候500毫巴等压面位势场。求出车贝雪夫的一些主要系数,讨论了这些系数的物理意义及其与我国温度、降水的关系。主要结果有: 1.表示大气经、纬向环流的车贝雪夫系数A_(10)、A_(01)与我国温度等级十年滑动平均和各地月平均温度存在相关关系。此关系的存在为温度趋势预报提供了可能性。 2.表示平均高度的A_(00)系数冬季12月的值和A_(10)系数冬季1月的值,两者组合成的复相关表为长江中、下游汛期(5—8月)降水趋势预报提供了可能性。用复相关表的结果,有三年做过长江中、下游汛期降水趋势预报,其结果与实况基本一致。     

STUDY ON CLIMATIC FEATURES OF SURFACE TURBULENT HEAT EXCHANGE COEFFICIENTS AND SURFACE THERMAL SOURCES OVER THE QINGHAI-XIZANG PLATEAU

Using monthly mean of surface turbulent heat exchange coefficients calculated based on datafrom four automatic weather stations(AWS)for thermal equilibrium observation in July 1993—September 1996 and of surface conventional measurements,an empirical expression is establishedfor such coefficients.With the expression,the heat exchange coefficients and the components ofsurface thermal source are computed in terms of 1961—1990 monthly mean conventional data from148 stations over the Qinghai-Xizang(Tibetan)Plateau(QXP)and its adjoining areas,and the1961—1990 climatic means are examined.Evidence suggests that the empirical expression is capable of showing the variation of the heatexchange coefficient in a climatic context.The monthly variation of the coefficients averaged overthe QXP is in a range of 4×10~(-3)-5×10~(-3).The wintertime values are bigger in the mountainsthan in the valleys and reversal in summer.Surface effective radiation and sensible heat are thedominant factors of surface total heat.In spring surface sensible heat is enhanced quickly,resulting in two innegligible regions of sensible heat,one in the west QXP and the other innorthern Tibet.with their maximums emerging in different months.In spring and summersensible heat and surface effective radiation are higher in the west than in the east.The effectiveradiation peaks for the east in October—December and the whole QXP and in June and October forthe west.The surface total heat of the plateau maximizes in May.minimizes in December andJanuary,and shows seasonal variation more remarkable in the SW compared to the eastern part.Inthe SW plateau the total heat is much more intense than the eastern counterpart in all the seasonsexcept winter.Under the effect of the sensible heat,the total heat on the SW plateau starts toconsiderably intensify in February,which leads to a predominant heating region in the west,withits center experiencing a noticeable westward migration early in summer and twice pronouncedweakening in July and after October.However,the weakening courses are owing to differentcauses.The total heat over the north of QXP is greatly strengthened in March.thus generatinganother significant thermal region in the plateau.