四川盆地盛夏旱涝非绝热热流量场分析

利用１９６４—１９８５年北半球５００ｈＰａ月平均非绝热热流量距平诊断资料，分析了四川盆地盛夏典型旱涝年份的热力特征及其形成的可能原因。发现四川盆地”西涝东旱”年和“西旱东涝”年非绝热热流量左异显著，呈反位相关系。提出夏季青藏高原非绝热加热异常，是影响四川盆地盛夏旱涝形成的重要原因。     

梅雨异常年大气非绝热加热场的比较分析

利用ＥＣＭＷＦ／ＷＭＯ客观分析格点资料，分析了多梅年和空梅年大气非绝热加热场特征。结果表明，梅雨期降水与大气非绝热和加热场有密切联系，梅雨各阶段的加热汤具有不同的特性，丰梅年与空梅年的加热场有显著差异。     

高原热力作用下的非绝热Rossby波

从含非绝热项的准地转运动方程组出发，分析了青藏高原大尺度热力作用下非绝热Rossby波的一些性质。从理论上证明当背景西风气流为正压时，冬季高原冷却作用有利于Roosby波的经向传播。又由非绝热Rossby波的频率方程说明冬季高原的热力作用是中高纬季节内振荡的重要激发机制。此外，当背景西风气流为斜压时，求解了高原热力作用下非绝热Rossby波的频率，并由频率方程说明冬季高原冷却作用有利于波动向不稳定方向发展，而夏季高原的大尺度热力作用对波动稳定性的影响存在临界值。     

非绝热加热对锋面次级环流的影响

通过考虑非绝热加热项和摩擦项的原始方程组，取沿锋面方向地转近似，导出一个描写定常锋面次级环流的方程，研究对流加热（ＣＩＳＫ）对锋面次级环流的作用。结果表明；非绝热加热能加强锋生过程，加强锋面环流，使环流宽度变窄，陡度加大。从而从理论上对锋面过程的降水不均匀性给出解释。     

夏季青藏高原地区水汽向平流层的等熵绝热和非绝热传输的气候学特征及其与落基山地区的对比

夏季亚洲季风区是对流层向平流层物质输送的主要通道,其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪（Microwave Limb Sounder,MLS）数据,首先对比分析夏季青藏高原周边上空水汽的分布特征,再利用再分析资料分析了对流层—平流层水汽传输的特征。结果表明:青藏高原周边特定的等熵面和对流层顶结构分布有利于水汽向平流层的绝热输送;在南亚高压的东北侧,从青藏高原到中太平洋地区,340~360 K层次存在最为显著的水汽向平流层的纬向等熵绝热输送通道,7~8月平均输送强度可达约7×103 kg s-1。此外,在伊朗高原及南亚高压的西部,350~360 K层次也存在一支水汽向平流层的经向等熵绝热输送通道,但强度相对较弱（约2.5×103 kg s-1）。在青藏高原南侧370~380 K层次存在强的水汽向平流层的非绝热输送,主要由深对流和大尺度上升运动引起,7~8月平均输送强度约0.4×103 kg s-1。落基山以东到大西洋西部,350~360 K层次存在水汽向平流层的纬向等熵绝热输送通道,但强度也弱得多（约2.5×103 kg s-1）。     

青藏高原热力作用下的非绝热Rossby波

从含非绝热项的准地转运动方程组出发，分析了青藏高原大尺度热力作用下非绝热Rossby波的一些性质，从理论上证明当背景西风气流为正压时，冬季高原冷却作用有利于Rossby波的经向传播，夏季高原大尺度热力作用不利于波动的经向传播。非绝热Rossby波的频率方程说明冬季高原的热力作用是中纬季节内振荡的重要激发机制。同时，在背景西风气流为纯斜压条件下，求解了高原热力作用下非绝热Rossby波的频率，并由频率方程说明冬季高原热力作用有利于波动向不稳定方向发展，而夏季高原的大尺度热力作用对波动稳定性的影响存在临界值。     

干绝热下沉导致的一次酷热天气分析

本文利用各种观测资料,对2002年7月15日华北部分地区酷热天气,酷热发生前和发生时的地面和高空天气形势进行了分析。温度垂直递减率以及用干空气绝热方程计算得到的地面温度与实况比较接近,说明酷热区上空为典型的干绝热下沉运动。     

非绝热加热对江淮气旋影响的数值模拟

本文采用数值模拟方法考察了潜热、感热和水汽蒸发等诸因素对江淮气旋的影响。对各种试验进行了涡度平衡与能量平衡的诊断分析,结果表明:江淮气旋初生时,扰动从基本气流中获得能量,正压不稳定起着重要作用;在江淮气旋发展后期,斜压性比较明显。潜热释放有意义地修正了系统的相速,一定程度上加强了系统的强度。海上感热和水汽蒸发促进了深对流发展,加大降水,同时加强了有效位能的释放,从而加强了系统发展,但它们的作用是有阶段性的。     

大气非绝热加热作用的研究进展与展望

大气非绝热加热与天气系统的发生发展有密切联系,与降水等天气过程密不可分,非绝热加热在大气运动中有着至关重要的作用。对非绝热加热的研究和理解,有助于改进数值预报模式,增强数值天气预报模式的预报能力。本文系统梳理了大气非绝热加热的基本内容,近几十年非绝热加热及其作用的研究成果,主要包括非绝热加热的概念及其表征、非绝热加热的时空分布特征、非绝热加热与季风、天气系统(如西太平洋副热带高压、热带气旋、温带气旋和急流)和降水之间的关系,以及非绝热加热在数值模式中的表征,进而指出有待于进一步研究的方面。     

亚——非季风区非绝热加热与夏季环流关系的诊断研究

基于热力适应理论,本文利用 ＮＣＥＰ／ ＮＣＡＲ再分析资料对撒哈拉沙漠、青藏高原和孟加拉湾地区的非绝热加热与夏季环流进行了诊断研究。在非洲撒哈拉沙漠地区,以感热输送为主的加热仅局限于近地面层,边界层以上的大气则以辐射冷却占优势。因而除了边界层内存在着浅薄的正涡度和微弱的上升运动以外,整个对流层几乎都维持负涡度并盛行下沉运动。对于青藏高原地区,强大的表面感热通量引起的垂直扩散是近地面大气加热的主要分量,与大尺度上升运动相关的凝结潜热对低层大气的加热也有一定的贡献。长波辐射造成的对流层中、上层大气的冷却则主要由深对流潜热释放来补偿。夏季高原地区总非绝热加热是正值,且最大加热率出现在边界层内。低空大气辐合产生正涡度,而中、高层大气辐散伴有较强的负涡度。因而高原盛行上升运动,最大上升运动位于近地面层。夏季孟加拉湾地区的深对流凝结潜热释放远大于长波辐的冷却作用,因而整个对流层几乎都保持较强的非绝热加热。４００ｈＰａ层附近的最大加热率引起３００－４００ｈＰａ最强的上升运动。对流层上层是负涡度区,而中、低层为正涡度区。结果还表明,垂直和水平辐散环流与大气的热源和热汇区密切相联：在高层,辐散气流从热源区流向热汇区;在低层则相     

NUMERICAL EXPERIMENTS OF THE INFLUENCE OF DIABATIC HEATING ON TROPICAL CYCLONE ASYMMETRIC STRUCTURE

Using the barotropic volticity equation that contains forcing from diabatic heating with appropriate parameterization. a number of numerical experiments are conducted for the tropical cyclone that is initially symmetric The result shows that the diabatic heating has important effects on the asymmetric structure in addition to the roll of the β term and nonlinear advection term in its formation. It again confirms the conclusion that the diabatic heating is a possible mechanism responsible for such structures in the tropical cyclone.     

DYNAMICAL STUDY OF DIABATIC HEATING INFLUENCE ON RADIAL INHOMOGENEOUS STRUCTURE OF TROPICAL CYCLONE

Based on the tropical cyclone(TC)asymmetric disturbance as the superposition of thesymmetric environmental circulation,the analytical solution of travelling wave is given by usingthe barotropical nondivergent model with diabatic heating forcing and non-friction in a plane polarcoordinate.Then,the TC radial inhomogeneous structure is analyzed on radial/tangential velocityand geopotential height.It is found that the different kinds of structures are influenced by theCoriolis parameter(f),TC intensity(Ω),disturbance circular frequency(ω),and TC angularwavenumber(m).And,the diabatic heating(Q_1)has significant impacts on the radial/tangentialvelocity distribution shaped like the inner-tight and outer-relaxed.     

IMPACTS OF DIABATIC PHYSICS PARAMETERIZATION SCHEMES ON MESOSCALE HEAVY RAINFALL SHORTRANGE SIMULATION

Based on the non-hydrostatic version of Mesoscale Model version 5 (MMS) and the data sets of four heavy rainfall scenarios occurring in August 2001 in China,this paper investigates the impacts of diabatic physical processes on predictions of dynamic and thermodynamic elements of heavy rainfall in China,deeply analyzes the effects of convective schemes on mesoscale heavy rain simulations and discusses the feasibility of using model physics perturbations in ensemble simulation of heavy rain,The results show that diabatic physical processes have little impact on the short-range prediction of geopotential height.However,planetary boundary layer schemes and convective schemes have significant influence on moisture divergence flux,vertical velocity,and unstable stratification,which are the three basic conditions of torrential rain.The forecast deviations in different convection schemes increase rapidly in the first 12 h time periods of simulation and the deviation structures are well correlated to that of sub-grid scale rainfall,while in the later periods of simulation with less correlation.Diabatie physical processes influence the structure and evolution of the simulations.For the rain storm events with a homogeneous thermal environmental condition in China.the numerical model ensembles could be created by perturbing the planetary parameterization scheme and convective parameterization.     

DYNAMICAL STUDY OF DIABATIC HEATING INFLUENCE ON RADIAL INHOMOGENEOUS STRUCTURE OF TROPICAL CYCLONE*

Based on the tropical cyclone (TC) asymmetric disturbance as the superposition of the symmetric environmental circulation,the analytical solution of travelling wave is given by using the barotropical nondivergent model with diabatic heating forcing and non-friction in a plane polar coordinate.Then,the TC radial inhomogeneous structure is analyzed on radial/tangential velocity and geopotential height.It is found that the different kinds of structures are influenced by the Coriolis parameter (f),TC intensity (Ω),disturbance circular frequency (ω),and TC angular wavenumber (m).And,the diabatic heating (Q₁) has significant impacts on the radial/tangential velocity distribution shaped like the inner-tight and outer-relaxed.     

非绝热加热对中高纬大气低频振荡的调频作用

用诊断方法和数值试验两种方法,研究了非绝热加热对中高纬大气低频振荡的调频作用,首先应用１９７９～１９８９年欧洲中心资料进行功率谱分析,得到：（１）夏季与冬季相比,波动的主周期有有缩短的趋势,（２）ＥｌＮｉｎｏ事件和ＬａＮｉｎａ事件期间,冬夏两季的波动主要周期分别有缩短和变长的趋势,然后,应用强迫耗散准地转正压涡度方程的全球谱模式,考虑三个行星波准共振,积分９０ｄ,得到：（１）三个行星波之间存在的很     

厄尔尼诺年和反厄尔尼诺年北半球500hPa非绝热热流量场的特征

本文应用谱方法,诊断、计算了1964—1985年间,6个厄尔尼诺年和6个反厄尔尼诺年北半球月、季大气非绝热热流量距平场。结果表明:厄尔尼诺现象对大气非绝热热流量距平场具有显著影响,大气的响应表现为低纬和中高纬非绝热热流量正负距平中心有组织的优势排列,其位相或强度存在低频振荡,并且差值中心表现为双月周期。反厄尔尼诺年,大气具有分布不变,但距平中心基本上为反位相的响应形式。最后,通过海气相关分析,指出了海温异常是决定大气非绝热热流量异常的最重要的原因。     

INTERDECADAL CHANGE OF DIABATIC FORCING OVER KEY REGION OF THE MARITIME CONTINENT AND ITS POSSIBLE RELATIONS WITH THE EAST ASIAN SUMMER MONSOON ANOMALIES

The Maritime Continent(MC) is an important region where the Tropical Pacific and the Indian Ocean interact with each other via "the atmospheric bridge" and a key region for the interaction between the Asian and Australian monsoons. Using the NCEP/NCAR and CMAP monthly mean reanalysis over the period of 1979-2012, the interdecadal variations of diabatic forcing over the key region of the Maritime Continent and its possible relations with the East Asian summer monsoon have been investigated in the present paper. Our results show that climate variations in the Maritime Continent is particularly significant in the area of 95-145°E, 10°S-10°N, which is thus defined as the key area of the MC(i.e., KMC area). Without the input of latent heat release in the atmosphere, distinct interdecadal change of diabatic heating is found to exist from 1979 to 2012; it intensified before 1980 s and peaked in the late 1980 s and weakened after this period. By analyzing each individual component that contributes to the diabatic heating in the KMC area, surface latent heat flux and net long-wave radiation in the atmosphere are found to be the two dominant components. With negative diabatic heating anomalies over KMC, there will be more precipitation on islands and less precipitation over sea, and more rainfall around the equator, which is in correspondence with the convergence center around the equator in the KMC area. Along the meridional-vertical section averaged between 115-120 ° E, the well-defined vertical circulation anomalies are observed with the ascending branches over KMC and the area around 30°N respectively, and the descending branch over the South China Sea. Water vapor transports from the Bay of Bengal and South China Sea to eastern China to benefit the positive precipitation anomalies. The meridional-vertical circulation in East Asia plays a critical role in linking the interdecadal variability of diabatic heating over the KMC and East Asian summer monsoon anomalies.     

IMPACT OF DIABATIC PROCESSES IN AGCM ON 4-DIMENSIONAL VARIATIONAL DATA ASSIMILATION*

The impact of diabatic processes on 4-dimensional variational data assimilation (4D-Var) was studied using the 1995 version of NCEP's global spectral model with and without full physics.The adjoint was coded manually.A cost function measuring spectral errors of 6-hour forecasts to "observation" (the NCEP reanalysis data) was minimized using the L-BFGS (the limited memory quasi-Newton algorithm developed by Broyden,Fletcher,Goldfard and Shanno) for optimizing parameters and initial conditions.Minimization of the cost function constrained by an adiabatic version of the NCEP global model converged to a minimum with a significant amount of decrease in the value of the cost function.Minimization of the cost function using the diabatic model, however,failed after a few iterations due to discontinuities introduced by physical parameterizations.Examination of the convergence of the cost function in different spectral domains reveals that the large-scale flow is adjusted during the first 10 iterations,in which discontinuous diabatic parameterizations play very little role.The adjustment produced by the minimization gradually moves to relatively smaller scales between 10-20th iterations.During this transition period,discontinuities in the cost function produced by "on-off" switches in the physical parameterizations caused the cost function to stay in a shallow local minimum instead of continuously decreasing toward a deeper minimum. Next,a mixed 4D-Var scheme is tested in which large-scale flows are first adiabatically adjusted to a sufficient level,followed by a diabatic adjustment introduced after 10 to 20 iterations. The mixed 4D-Var produced a closer fit of analysis to observations,with 38% and 41% more decrease in the values of the cost function and the norm of gradient,respectively,than the standard diabatic 4D-Var,while the CPU time is reduced by 21%.The resulting optimal initial conditions improve the short-range forecast skills of 48-hour statistics.The detrimental effect of parameterization discontinuities on minimization was also reduced.     

RELATIONSHIPS BETWEEN THE POSITION VARIATION OF THE WEST PACIFIC SUBTROPICAL HIGH AND THE DIABATIC HEATING DURING PERSISTENT INTENSE RAIN EVENTS IN YANGTZE-HUAIHE RIVERS BASIN

By using NCEP/NCAR daily reanalysis data and daily precipitation data of 740 stations in China, relationships between the position variation of the West Pacific subtropical high (WPSH) and the diabatic heating during persistent and intense rains in the Yangtze-Huaihe Rivers basin are studied. The results show that the position variation of WPSH is closely associated with the diabatic heating. There are strong apparent heating sources and moisture sinks in both the basin (to the north of WPSH) and the north of Bay of Bengal (to the west of WPSH) during persistent and intense rain events. In the basin, Q 1z begins to increase 3 days ahead of intense rainfall, maximizes 2 days later and then reduces gradually, but it changes little after precipitation ends, thus preventing the WPSH from moving northward. In the north of Bay of Bengal, 2 days ahead of strong rainfall over the basin, Q 1z starts to increase and peaks 1 day after the rain occurs, leading to the westward extension of WPSH. Afterwards, Q 1z begins declining and the WPSH makes its eastward retreat accordingly. Based on the complete vertical vorticity equation, in mid-troposphere, the vertical variation of heating in the basin is favorable to the increase of cyclonic vorticity north of WPSH, which counteracts the northward movement of WPSH and favors the persistence of rainbands over the basin. The vertical variation of heating in the north of Bay of Bengal is in favor of the increase of anti-cyclonic vorticity to the west of WPSH, which induces the westward extension of WPSH.     

江淮流域持续性强降水期间西太副高位置变异与非绝热加热的关系

采用NCEP/NCAR逐日再分析资料及全国740站逐日降水资料,讨论了江淮流域持续性强降水期间西太平洋副高位置变动特征及其与非绝热加热的关系.通过个例合成研究发现:副高位置变异与强降水持续期间大气非绝热加热关系密切.强降水持续期间,副高北侧的江淮流域和西侧的孟加拉湾北部地区均存在强烈的视热源和视水汽汇.强降水发生前3 ...