Using a Modified Soil-Plant-Atmosphere Scheme(MSPAS)to Simulate the Interaction between Land Surface Processes and Atmospheric Boundary Layer in Semi-Arid Regions

This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts: atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feasibility of the model is well proved in this paper. The numerical simulation results from MSPAS show good agreement with reality. The scheme is used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature of boundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity, turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS is used to simulate the interaction between desert and oasis at night, and again it obtains reasonable results. This indicates that MSPAS can be used to study the interaction between land surface processes and the atmospheric boundary layer over various underlying surfaces and can be extended for regional climate and numerical weather prediction study.

A Variational Multiscale Method for Particle Dispersion Modeling in the Atmosphere

A LES model is proposed to predict the dispersion of particles in the atmosphere in the context of Chemical,Biological,Radiological and Nuclear(CBRN)applications.The code relies on the Finite Element Method(FEM)for both the fluid and the dispersed solid phases.Starting from the Navier-Stokes equations and a general description of the FEM strategy,the Streamline Upwind Petrov-Galerkin(SUPG)method is formulated putting some emphasis on the related assembly matrix and stabilization coefficients.Then,the Variational Multiscale Method(VMS)is presented together with a detailed illustration of its algorithm and hierarchy of computational steps.It is demonstrated that the VMS can be considered as a more general version of the SUPG method.The final part of the work is used to assess the reliability of the implemented predictor/multicorrector solution strategy.

Hydrocarbon test in lower-layer atmosphere to predict deep-sea petroleum or hydrate in the Okinawa Trough: an example

Light hydrocarbon (methane, ethane, propane, butane and CO2) test and C isotopic analysis of CO are conducted for over 100 lower-layer atmospheric samples from the East China Sea slope and the Okinawa Trough. The results show that the lower-layer atmosphere mainly consists of CO2 and then of CH4, and the CO2 concentrations are calculated to have a high average value of 0.87 omega/10(-2) about three times that of the regional background (0-3 omega/10(-2)). The result also shows that the average value of C isotope - 20.8 x 10(-3) is given to the CO2, inferring that it is inorganic gas. Thus, for the future 's work in the Okinawa Trough, special attention should be paid to CO2 hydrate, which is very possibly an important hydrate type.

The Possibilities of Using the Minimax Method to Diagnose the State of the Atmosphere

The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air.Within the framework of this study,the task of probabilistic forecasting of diagnostic parameters and their combinations,leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere,was carried out.It is this state that,as shown by previous studies,a priori contribution to the development of a number of weather phenomena dangerous for society(squalls,hail,heavy rains,etc.).The results of applying the minimax method made it possible to identify a number of parameters,such as the intensity of circulation,the activity of the Earth’s magnetosphere,and the components of the geostrophic wind velocity,the combination of which led to the development of instability.In the future,it is possible to further expand the number of diagnosed parameters to identify more sensitive elements.In this sense,the minimax method,the usefulness of which is shown in this study,can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.

THE EFFECTS OF ROUGHNESS CHANGE ON THE SURFACE LAYER OF THE ATMOSPHERE(Ⅰ)--THE VARIATIONS OF WIND SPEED AND SHEAR STRESS

A general four-layer structure linear theory for predicting the effects of arbitrarily distributed roughness change on the variations of wind speed and shear stress in the surface layer of 3D and 2D atmospheres was presented.The results derived by the theory were agreeable to the previous ones.

Characteristics of Hydrologic Transfer between Soil and Atmosphere over Gobi near Oasis at the End of Summer

By utilizing the data observed at Dunhuang during August and September 2000 in the 'Field Experiment on Interaction between Land and Atmosphere in the Arid Region of Northwest China (FEILARNC)', the characteristics of the soil moisture, temperature, and atmospheric humidity are analyzed. It is found that the thickness of the soil temperature active layer is about 5 cm and much thinner than is typical, that not only the atmospheric humidity gradient is often inverted but also the soil moisture gradient in the shallow layer in the Gobi near oasis, that the diurnal variation of soil moisture can be divided into the four stages that are called the wet stage, the losing-water stage, the dry stage, and the attaining-water stage. It is shown that in soil moisture profiles, the depth of the soil moisture active layer is about 10 cm and soil moisture inversion is the main feature in the shallow layer during the wet stage. Such a feature as soil moisture inversion indicates that soil in the shallow layer can inhale moisture from the air through condensation in the nighttime and exhale moisture to the air through evaporation in the daytime. The condensation and evaporation constitute together the full respiration process of moisture on the ground. The formation of soil moisture inversion is related with the state of soil temperature and moisture, the intensity of atmospheric humidity inversion, and the atmospheric thermodynamic stability.

Advances in Researches on the Middle and Upper Atmosphere in 2008-2010

This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010.The focuses are specifically placed on the researches being associated with ground-based observation capability development,dynamical processes,the property of atmospheric circulation and the chemistry-climate coupling of the middle atmospheric layers.

Lidar Measurements of Aerosols in the Tropical Atmosphere

Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, Pune (18°32'N, 73°51'E, 559 m AMSL), India. These observations carried out during nighttime in the lower atmosphere (up to 5.5 km AGL), employing an Argon ion / Helium-Neon lidar provided information on the nature, size, concentration and other characteristics of the constituents present in the tropical atmosphere. The time-height variations in aerosol concentration and associated layer structure exhibit marked differences between the post-sunset and pre-sunrise periods besides their seasonal variation with maximum concentration during pre-monsoon / winter and minimum concentration during monsoon months. These observations also revealed the influence of the terrain of the experimental site and some selected meteorological parameters on the aerosol vertical distributions. The special observations of aerosol vertical profiles obtained in the nighttime atmospheric boundary layer during October 1986 through September 1989 showed that the most probable occurrence of mixing depth lies between 450 and 550 m, and the multiple stably stratified aerosol layers present above the mixing depth with maximum frequency of occurrence at around 750 m. This information on nighttime mixing depth / stable layer derived from lidar aerosol observations showed good agreement with the height of the ground-based shear layer / elevated layer observed by the simultaneously operated sodar at the lidar site.

Estimate Totel Number of the Earth Atmospheric Particle with Standard Atmosphere model

The total number of atmospheric particle (AP) is an important datum for planetary science and geoscience. Estimating entire AP number is also a familiar question in general physics. With standard atmosphere model, considering the number difference of AP caused by rough and uneven in the earth surface below, the sum of dry clean atmosphere particle is . So the whole number of AP including water vapor is . The rough estimation for the total number of AP on other planets (or satellites) in condensed state is also discussed on the base of it.

Advances in the Researches of the Middle and Upper Atmosphere in China

In this report we summarize the research results by Chinese scientists in 2018–2020.The focuses are placed on the researches of the middle and upper atmosphere,specifically the researches on atmospheric structure and composition,climate and chemistry-climate coupling and climate modelling,dynamics in particular those inducing the coupling of the atmospheric layers.

The Thermal Inertia Characteristics of the System Ocean-Atmosphere

To estimate the time delay between the planetary temperature change and the change of the incoming solar radiation fraction absorbed by the ocean and the atmosphere, the analytical energy balance model is presented. The model generalization allows of using averaged data for model parameterization. Using the model, the time delay is investigated on four model cases of absorbed radiation change. The interconnections among the time delay, the planetary thermal inertia and the ocean active layer depth are established.

Characteristics of atmospheric boundary layer structure and its influencing factors under different sea and land positions in Europe

This study identifies quantitatively the dominant contributions of meteorological factors on the development of the boundary layer heights(BLH)in the European region,based on 32 years(1990-2021)of radiosonde observations.The spatial variability of the BLH is further discussed by location,by classifying recording stations as inland,coastal,or bay.We find that the BLH in Europe varies considerably from day to night and with the seasons.Nighttime BLH is higher in winter and lower in summer,with the highest BLH recorded at coastal stations.Daytime BLH at coastal stations shows a bimodal structure with peaks in spring and autumn;at inland and bay stations,daytime BLH is lower in winter and higher in summer.The daily amplitudes of BLH at the inland and bay stations are stronger than those at coastal stations.Based on our multiple linear regression analysis and our decoupling analysis of temperature and specific humidity,we report that the development of the nighttime BLH at all types of stations is strongly dominated by the variations of surface wind speed(and,at coastal stations,wind directions).The main contributors to daytime BLH are the near-surface temperature variability at most coastal and inland stations,and,at most bay stations,the variation of the near-surface specific humidity.

Preliminary Investigation of Total Ozone Column and Its Relationship with Atmospheric Variables

This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to study the dynamic effect of ozone on climate and vice versa. This is due to the fact that ozone and climate influence each other and the understanding of the dynamic effect of the interconnectivity is still an open research area. Monthly mean daily TOC and cloud cover data were obtained from the Earth Probe Total Ozone Mass Spectroscopy (EPTOMS) and the International Satellite Cloud Climatology Project (ISCCP)-D2 datasets respectively. Bivariate analysis and Mann Kendall trend tests were used in data analysis. MATLAB and ArcGIS software were employed in analyzing the data. Results reveal that TOC increased spatially from the coastal region to the north eastern region of the country. Seasonally, the highest value of TOC was observed at the peak of rainy season when cloud activity is very high, while the lowest value was recorded in dry season. These variations were attributed to rain producing mechanisms and atmospheric phenomena which influence the transport and distribution of ozone. Furthermore, the statistical analysis reveals significant relationship between TOC and low and middle cloud covers in contrast to high cloud cover. This relationship is consistent with previous studies using other atmospheric variables. This study has given scientific insight which is useful in understanding the coupling of the lower and upper atmosphere.

高海拔低气压条件下烟气辐射特性

高原地区特殊的地理环境导致锅炉运行出现出力不足、排烟温度高等一系列问题。采用逐线法(Line-By-Linemethod, LBL),基于HITEMP2010光谱数据库(High-temperaturemolecular spectroscopic database),求解3组不同气压条件下(0.101 325、0.076 622和0.061 655 MPa)空气燃烧方式的烟气吸收系数和总发射率,分析了压力、温度和水蒸气与CO_(2)的摩尔比对烟气辐射特性的影响,改进了灰气体加权和(Weighted-Sum-of-Gray-Gases,WSGG)模型关联式,建立了适用于低气压条件下的WSGG模型参数。结果表明,压力的降低会减小烟气的总发射率,4种工况下压力从0.101 325 MPa下降到0.061 655 MPa时,总发射率随行程长度变化的最大差值分别为0.093 4、0.084 5、0.091 1和0.084 3。在小行程长度下,摩尔比越大,压力的变化对总发射率的影响越大,而大行程长度下则相反。温度的升高会减小烟气的总发射率,4种工况下,温度从1 000 K升到2 500 K时,总发射率随行程长度变化的最大差值分别为0.273 6、0.270 5、0.251 5和0.250 5。在小行程长度下,摩尔比越大,温度的变化对总发射率的影响越大,在大行程长度下则相反。摩尔比的增加会增大烟气的总发射率,4种工况下摩尔比从1增加到2时,总发射率随行程长度变化的最大差值分别为0.088 1、0.100 4、0.088 9和0.100 6。在小行程长度下,温度越高或压力越低,摩尔比变化对总发射率的影响越小,在大行程长度下则相反。改进后的WSGG模型在不同工况下烟气总发射率的最大相对误差为3.67%,相比现有基于常压条件下开发的WSGG模型外推到低压条件的误差有明显降低,表明改进后的WSGG模型更适用于低气压空气燃烧气氛。

大气总温传感器数值计算耦合分析技术

借助自研软件开发及现有的商业软件建立阻滞室大气总温传感器模型,用UG软件构建几何模型,以商用Fluent软件模拟传感器的三维CFD数值,采用共形网格划分实现大气总温传感器的流体与固体界面网格匹配。采用Realizable k-ε湍流模型以及数值仿真批处理脚本的方法,对大气总温传感器流、固耦合仿真进行计算,提高了仿真计算效率。利用该方法对常温常压风洞对大气总温传感器的校准进行仿真分析,得出常温常压条件下马赫数大于1时,恢复修正系数基本不随马赫数变化。在常温、马赫数为0.6条件下,在静压条件±0.1atm时或总温条件为-25~45℃时,恢复修正系数变化幅度很小,数值仿真结果具有一定的准确性。

边界层高度的不同诊断方法在京津冀及周边地区的适用性分析

利用2016~2021年京津冀及周边地区7个站的探空数据,分析了传统的位温梯度法、改进的位温梯度法、相对湿度梯度法、比湿梯度法和理查森数法5种大气边界层高度的诊断方法在京津冀及周边地区大气边界层高度计算的适用性。结果表明:5种方法计算的边界层高度差距在40~1000 m,传统的位温梯度法、相对湿度梯度法、比湿梯度法诊断的边界层高度普遍偏高,且存在较大的结构不确定性,理查森数法和改进的位温梯度法诊断的边界层高度偏低,前者的不确定性最小;5种方法在乐亭、北京、太原3个代表站得到的边界层高度具有明显的季节性和季节内差异,两种湿度法在乐亭呈现夏秋高、春冬低的特点,在北京和太原呈现春夏高、秋冬低的特点,其他3种方法在3个站均是春夏高、秋冬低的特点;相对湿度梯度法和比湿梯度法参数不确定性较大,传统的位温梯度法和改进的位温梯度法次之,理查森数法最小;在边界层高度计算结果月均值的时间一致性上,晚上各方法间的相关性明显高于白天,两种湿度法之间的相关系数始终最高,但与另外3种方法间的相关性均较差,理查森数法和改进的位温梯度法相关性较高,传统的位温梯度法因站点不同,与其他方法间的相关性波动较大。

塔克拉玛干沙漠腹地晴天与沙尘暴天气大气边界层对比分析

根据2017、2019年7月塔克拉玛干沙漠腹地GPS探空和地面观测数据,利用位温廓线法等方法,对比分析了沙漠腹地夏季晴天和沙尘暴天气大气边界层结构变化特征。结果表明:晴天和沙尘暴天气大气边界层结构特征显著不同。晴天大气边界层各气象要素垂直分布较为均一,白天对流边界层深厚,高度接近5 km,夜间稳定边界层一般在500 m左右。沙尘暴天气边界层内位温和比湿垂直变化较小,风速较大,可达24.0 m/s,其白天对流边界层在1.5 km左右,夜间稳定边界层在1 km左右。晴天辐射强烈,地表升温迅速,湍流旺盛,是形成晴天深厚对流边界层的主要因素。大尺度天气系统冷平流的动力条件,以及云和沙尘减弱了到达地表的辐射强度是形成沙尘暴天气独特的大气边界层结构的主要因素。

基于小波多尺度分析大气边界层高度提取方法研究

大气边界层物理演变特征及复杂边界层结构对大气污染过程的影响机制研究中,迫切需要边界层精细化结构的探测手段。通常使用梯度法和小波协方差变换法的方式进行边界层高度提取,但由于该方式容易受到噪声和气溶胶层结构的影响,实验误差较大。提出使用小波多尺度分析方法细化边界层特征结构,从而筛选出有效的细节信息,提高对探索边界层高度的准确性。此外,基于GBQ L-01激光雷达设备实测合肥地区全天气溶胶分布情况,使用小波多尺度分析方法分析对应的平行分量距离平方矫正信号、垂直分量距离平方矫正信号和退偏振比全天分布情况。实验结果表明,该方法准确性高,与梯度法、小波协方差法相比具有更高的稳定性与连续性。对特殊时间点进行数据分析,明确主要影响边界层高度的主要因素,并确定各个时间段的大气边界层高度值。

不同风场中特高压换流站阀厅屋盖风压特性试验研究

特高压(ultra high voltage,UHV)换流站阀厅的金属屋面系统在风荷载作用下易发生屋面表层风揭事故。为深入探讨该类建筑屋面的风压极值特性,基于风洞试验分别探讨了大气边界层(atmospheric-boundary-layer,ABL)风、壁面射流、均匀湍流三种风场作用下的屋面风压特性,比较了平均风剖面、风速、风向、湍流强度等因素对屋面风压的影响。结果表明:阀厅屋盖迎风前缘负风压最大,且控制风向角在45°左右;壁面射流风场下平均风压系数与脉动风压系数均超过大气边界层风场的结果;风速对阀厅屋盖的负风压系数均值和极值影响较小,而湍流度对风压系数的极值影响较大;大气边界风场时,JGJ/T 481—2019《屋盖结构风荷载标准》的最不利风压系数建议值偏于安全;而在壁面射流风场下,阀厅屋盖全风向最不利风压系数在所有区域都大于JGJ/T 481—2019的建议值,设计中应加以重视。

中国夏季边界层高度及其主要影响因子的分区研究

中国区域下垫面复杂且边界层热力和动力影响因子众多,目前缺乏对全国范围内边界层高度及其影响因子的综合分析。本文基于2012~2016年L波段高分辨率探空资料,采用K-prototypes算法结合12个可能影响因子将中国夏季边界层高度进行了聚类分析,以探讨中国夏季边界层高度的区域性特征和主要影响因子。结果表明,中国区域100个站点08、14、20时(北京时,下同)的边界层高度均可划分为东北、东南、西北和西南4个区域。在此基础上,分析了三个不同时次不同区域边界层高度的主要影响因子,并探究这些因子影响不同热力状态下边界层发展的可能机理。结果表明:稳定边界层早(08时)、晚(20时)的发展主要受风速湍流动力作用的影响,而中午14时的发展与间歇性湍流作用密切相关。中性和对流边界层的发展在早上也主要受风速的驱动,而在中午则主要受较高地表温度和较大地表净辐射通量所引起的湍流热力作用驱动。此外,东北地区的云量和比湿、东南地区的潜热通量、西北地区的感热通量和比湿、西南地区的感热通量和土壤湿度也会通过对热力湍流的直接或间接影响,从而影响该区域中性和对流边界层的发展。晚上,由于东西时差的影响,在东部地区,风速开始成为中性和对流边界层高度的主要影响因子,而西部地区边界层高度的主要影响因子仍为热力因子。值得注意的是,北部地区的叶面积指数可以通过植被蒸腾作用改变比湿,从而影响边界层的发展;东北地区地表气压的变化可以通过影响气流的上升和下沉运动从而影响边界层的发展。