Dynamic model of accumulation of total biomass of agricultural crops

Issues concerning the growth and biological time of agricultural crops are under consideration. A closed system of equations is derived for calculating total dry biomass and biological time of plants. The model parameters are given, and the model is verified based on the experimental data of observations of the sunflower in the southern conditions of the Ukraine.     

2005年夏季中国东部气候异常分析--中国科学院大气物理研究所短期气候预测检验

简要比较了中国科学院大气物理研究所对2005年夏季中国降水跨季度预测与实况的异同,并对2005年夏季我国主要雨带及降水偏少区的形成与东亚热带、副热带以及中高纬度大气环流系统的配置进行了分析。对2005年夏季西太平洋副高的异常活动预测不好,这是造成跨季度降水预测有失误之处的主要原因之一。2005年夏季在亚洲对流层中高层,沿着副热带急流轴准静止Rossby波有几次能量传播过程,西太平洋副高的北抬与西伸与副热带急流中Rossby波的活动强度有一定的对应关系,因而产生了亚洲不同地区高影响性的灾害性天气。     

T106数值预报产品在赣南温度预报中的释用

利用1995年7～9月、1996年7～8月24～144h、1000～500hPa的T106格点资料与赣南17个县（市）的最高、最低、平均温度作相关分析;用逐步回归方法建立了分县逐日滚动预报方程。并用1996年9月份T106格点资料对方法进行检验,同时对预报方法及T106产品在温度预报中的释用能力作了初步分析。     

测量NO气体吸收截面的方法

差分吸收光谱技术(DOAS)已经被广泛用于各种污染气体浓度的测量,其中影响其测量精度的主要因素就是气体吸收截面的测量.利用Lambert Beer 吸收定律以及自主设计的测量装置对大气的主要污染气体NO的吸收截面进行了测量,并采用多项式拟合的方法提高了测量的精度,根据所测得的吸收截面反演了NO气体的浓度值,取得了良好的效果.     

RG13型雨量传感器测量结果的不确定度评定

国内民航机场主要使用的雨量观测设备为芬兰维萨拉公司生产的RG13型雨量传感器,为保证雨量测量数据的真实可靠,对其测量结果的不确定度分析很有必要。根据自动气象站现场校准方法,分别进行大雨强和小雨强的重复测试,并依据JJF1059.1-2012测量不确定度的评定与表示要求,进行A类不确定度评定。分析测量过程中的B类不确定度来源,进行B类评定,最终给出扩展不确定度。结果表明：在小雨强下,测量不确定度为U95=0.17mm,包含因子k=2。在大雨强下,测量不确定度为U95=0.16mm,包含因子k=2。该研究完善了雨量传感器的现场校准工作流程,对雨量传感器测量结果的可信度评定具有参考价值。     

贵州玉屏四季气候季节的划分及特征分析

利用玉屏国家地面气象观测站1961—2016年逐日平均气温资料,采用《气候季节划分》(QX/T15—2012)方法,对玉屏县四季起始日期及长度进行分析。结果表明:(1)玉屏县常年四季起始日期:入春3月5日,入夏5月23日,入秋9月22日,入冬11月28日;四季长度:春季79 d,夏季122 d,秋季67 d,冬季97 d。(2)56 a来玉屏县春季起始日期呈提前趋势,长度呈增加趋势,两者均在20世纪90年代前后出现了转折,但未发生气候突变;夏季起始日期及长度趋势变化不明显;秋季起始日期呈推后趋势,长度变化不明显;冬季起始日期变化不明显,长度呈减少趋势;春季长度增加、冬季长度减少主要为春季起始日期提前所致。(3)玉屏县四季起始日期的年际变幅大,起始日期比常年偏早(晚)连续2候以上的异常年份,春季为23%,夏季为27%,秋季为32%,冬季为25%。(4)玉屏县春季开始后出现低于季节指标≥1候的概率达41%,表明玉屏县春季出现倒春寒天气的概率很大。(5)比较气象行标法与稳定通过法的四季起始日期及长度,气象行标法对玉屏县的四季划分更能满足于农业生产的需要。     

热带气旋眼墙非对称结构的研究综述

热带气旋的眼墙非对称结构与其发展过程密切相关。在热带气旋移动过程中,非对称风场伴随着边界层内非对称摩擦而引起的辐合,影响着热带气旋眼墙内的对流分布。此外,风垂直切变作为影响热带气旋强度的重要因子,将上层暖心吹离表层环流,引起眼墙垂直运动的非对称,导致云、降水在方位角方向的非均匀分布。当存在平均涡度的径向梯度时,罗斯贝类型的波动可以存在于涡旋内核区域,影响眼墙非对称结构。海洋为热带气旋提供潜热和感热形式的能量,是热带气旋发展的重要能量来源,关于海洋如何影响热带气旋眼墙非对称结构的相关研究较少。文中着重回顾了热带气旋与海洋相互作用的研究成果,并提出海洋影响热带气旋眼墙非对称结构的机制。海洋对热带气旋最显著的响应特征是冷尾效应,该效应通过降低海表温度,减少海洋向大气输送的潜热和感热,从而影响热带气旋眼墙非对称结构。此外,海浪改变海表粗糙度,通过边界层影响移动热带气旋的眼墙结构。     

2004年安徽省梅汛期三次暴雨过程的大气低频振荡背景

对2004年夏季安徽省降水以及850 hPa涡度、水汽通量散度场进行Morlet小波分析，结果发现:6月中下旬，三者都存在着2~6 d，7~15 d以及18~30 d的振荡周期，并且三者的各频带的低频分量与实际降水距平的对应关系较好。其中18~30 d低频涡旋系统和水汽通量散度具有源自孟加拉湾和中南半岛自西南向安徽省传播特征；7~15 d低频涡旋系统主要是沿着中纬度地区自西向东传入安徽省，低频水汽通量散度则由低纬度地区自南向北传入安徽省。6月中下旬赤道西太平洋地区沿东南-西北向移动的7~15 d低频气旋和反气旋波列，以及安徽省附近低层流场的2~6 d高频变化，为其6月中下旬的三次强降水过程提供了有利条件。     

Review of measurements of the RF spectrum of radiation from lightning

Summary A review is presented of the measurements reported in the literature of the spectrum of electromagnetic radiation from lightning in the frequency range from 1 kHz to 1 GHz. Measurements have been made either by monitoring the power received at inidividual frequencies using a narrow bandwidth recording device or by recording the transient (time dependent) radiation with a wide bandwidth device and then Fourier transforming the waveform to obtain a spectrum. Measurements of the first type were made extensively in the 1950's and 1960's and several composite spectra have been deduced by normalizing the data of different investigators to common units of bandwidth and distance. The composite spectra tend to peak near 5 kHz and then decrease roughly as 1/(frequency) up to nearly 100 MHz where scatter in the data make the behaviour uncertain. The spectrum obtained with measurements of the second type is similar. Recent experiments have extended the frequency range covered to several 10's of MHz and include spectra for return strokes, the stepped leader and for some intracloud processes. The spectrum of first return strokes obtained in this manner is very similar to the spectrum of the composite flash obtained from the narrowband measurements.With 9 Figures     

甘肃干旱半干旱地区林木蒸散量估算和水分适生度研究

采用张宝堃和H.L.彭曼的气候学方法,对甘肃干旱半干旱区各县、市林木生长期的蒸散耗水量进行了估算,并与实测和调查资料进行了对比,结果表明:两种估算值大致可反映乔木薪炭林和乔木用材林生长对水分的需求。文中还给出了各县、市年和日平均气温≥10℃期间的实际水资源。根据各地林木生长期的耗水量指标和实际水资源,采用实际湿润度方法确定了各地不同气候植被区林木的水分适生度。     

2005年运城地区苹果成花率低的气候条件分析

运城2005年苹果成花率低,多数果园只有2004年的1/4～1/5,不少果园还出现了“空树”现象,主要是由于2004年果树的各花芽分化阶段不良气候条件以及果树光合产物不足,致使花芽分化与果树花果之间产生了营养竞争而使得果树花芽分化受到了抑制,使得果树大部分花芽转向了叶芽,从而导致了2005年果树成花大量减少。     

Identification of zones of atmospheric fronts as a problem of postprocessing the results of numerical prediction

Presented is a review of the results of the studies that have been carried out in recent 15 years at the Hydrometcenter of Russia and deal with the objective analysis of atmospheric fronts and with diagnostic computations on the base of the results obtained. A unique experiment on the quantitative estimation of the measure of subjectivity of the frontal analysis carried out by weather forecasters in operational mode was accomplished in the process of the method development. Differences turned out to be so significant that no concrete synoptic archive can be considered as a source of actual data on the position of fronts. At the same time, the degree of agreement between different forecasters concerning the position of primary cold and warm fronts remains practically significant. The statistical method of objective analysis of atmospheric frontal zones is worked out as a method of postprocessing the results of numerical forecast (objective analysis) of the fields of pressure (geopotential), temperature, and humidity. The proposed method was operationally tested and recommended for the operational use by the Roshydromet Central Methodological Committee for Hydrometeorological and Heliophysical Forecasts. The data on precipitation at the stations (a degree of precipitation intensity on the front characterizes its activity) are used as a predictant (criterion of the absence or presence of a front). The frontal parameter initially obtained as a probability of the fact that the forecaster draws the front through the given grid cell is (in its physical essence) a quantitative characteristic of baroclinity near the surface and in the layers of 850-500 and 925-700 hPa and of cyclonicity of the surface pressure field. This variable turned out to be an effective diagnostic characteristic of baroclinic forcing of vertical circulations and formation of clouds and precipitation in frontal zones. The spectra of the frequency of precipitation of various intensity for different seasons and regions of the European part of the former USSR are constructed using the long-term data on two main characteristics of precipitation forcing, namely, the frontal parameter and the height of the convection level. Given are other potential application areas of the frontal parameter including the verification of numerical models.     

A study of the effect of topography on the merging of vortices

Eight sets of numerical experiments are performed in 48 hours of integtation by using a barotropic primitive equation model with a topographic term so as to investigate the effect of topography on the merging of vortices. It is pointed out that the introduction of topography may change the track of vortices,and it causes the low vortices and vorticity lumps to be detained on the southeast side of the topography,thus creating a favorable condition for the merging of the low vortex and vorticity lumps. It is also shown that the effect of topography may cause double mergers of vortices in a horizontally shearing basic flow,and it can strengthen the low vortex remarkably.     

广西汛期暴雨若干特征分析

对１９５９—２０００年广西汛期（４～９月）暴雨的年、月分布和广西汛期暴雨天气过程的季节分布及主要影响天气系统进行深入分析，得到了广西汛期暴雨的若干重要特征，对广西汛期划分提出了改进意见。     

Estimation of the error of lidar determination of the transparency of low-turbidity atmosphere

Considered is the method of determination of atmospheric turbidity using weak lidar signals when the problem is mathematically incorrect due to the presence of the background noise. An accuracy of the method can be increased by means of using the procedure of effective averaging and linear approximation of the transmission in the case of the low attenuation coefficient.     

西风带南支槽对云南天气的影响

利用1980-2008年近30年逐日地面、高空观测资料,统计了影响云南的西风带南支槽个例,并分析了南支槽的时空分布和对云南降水的影响。结果表明,影响云南的南支槽平均每年出现18.76次,11月-次年5月平均每月出现次数相当(6-10月西风带北撤,转换为孟加拉湾槽);约5.88%的南支槽过程对云南产生大到暴雨天气,54.83%的南支槽产生小到中雨,另有17.28%的南支槽产生冰雹天气过程。南支槽的进退与西风带环流形势、副热带高压位置和高原大地形等关系密切,南支槽位置、水汽输送、湿度锋区、低空急流和冷空气强弱等条件的不同决定了降水的强弱或是否有强对流天气出现。     

Problems of exploration level of hydrometeorological regime of the Northern Caucasus territory

The main problems of the study of the meteorological regime, climate, hydrology, snow avalanches, mudflows, and glaciers are considered. It is demonstrated that the level of their exploration on the plain territory is sufficient on the whole, however, the mountain territories are poorly studied. The opening of new stations including the automatic ones and the organization of snow-route observations are required. It is necessary to carry out the preparation and publishing of new handbooks on the climate and surface water resources and to create the catalogs of glaciers, snow avalanches, and mudflows on the basis of the modern topographic maps and satellite images.     

Analysis of Basic Features of the Onset of the Asian Summer Monsoon

In this paper,a relatively systematic climatological research on the onset of the Asian tropical summer monsoon(ATSM)was carried out.Based on a unified index of the ATSM onset,the advance of the whole ATSM was newly made and then the view that the ATSM firstly breaks out over the tropical eastern Indian Ocean and the middle and southern Indo-China Peninsula was further documented,which was in the 26th pentad(about May 10),then over the South China Sea(SCS)in the 28th pentad.It seems that the ATSM onset over the two regions belongs to the different stages of the same monsoon system.Then,the onset mechanism of ATSM was further investigated by the comprehensive analysis on the land-sea thermodynamic contrast,intraseasonal oscillation,and so on,and the several key factors which influence the ATSM onset were put forward.Based on these results,a possible climatological schematic map that the ATSM firstly breaks out over the tropical eastern Indian Ocean,the Indo-China Peninsula,and the SCS was also presented, namely seasonal evolution of the atmospheric circulation was the background of the monsoon onset;the enhancement and northward advance of the convections,the sensible heating and latent heating over the Indo-China Peninsula and its neighboring areas,the dramatic deepening of the India-Burma trough,and the westerly warm advection over the eastern Tibetan Plateau were the major driving forces of the summer monsoon onset,which made the meridional gradient of the temperature firstly reverse over this region and ascending motion develop.Then the tropical monsoon and precipitation rapidly developed and enhanced. The phase-lock of the 30-60-day and 10-20-day low frequency oscillations originated from different sources was another triggering factor for the summer monsoon onset.It was just the common effect of these factors that induced the ATSM earliest onset over this region.     

Evaluation of different versions of NCUM global model for simulation of track and intensity of tropical cyclones over Bay of Bengal

The global UK Met office Unified Model (UM) is currently operational at National Centre for Medium Range Weather Forecasting (NCMRWF), the global model named as NCUM. An inter-comparison of two different versions of NCUM has been carried out for simulating the track and intensity of Tropical Cyclones (TCs), which formed over the Bay of Bengal (BoB). For this purpose, two series of numerical experiments named as NCUM25 (New Dynamical core with NCUM N512 resolution) and NCUM17 (ENDGame core with NCUM N768 resolution and upgraded physics and data assimilation scheme) are carried out with seven different initial conditions (ICs) for two TCs. The results suggested that the location, intensity, and vertical structure of the TCs are reasonably well predicted by the NCUM17 over the NCUM25. The Direct Position Error (DPE) and landfall error of TCs are reduced in the NCUM17 in comparison to the NCUM25 for all initial conditions. The mean DPEs and intensity error are reduced by 21–41% and 18–21% in NCUM17 over NCUM25 in both the cases respectively. Improvements in mean landfall position errors are shown to range from 43 to 65% in the NCUM17 as compared to the NCUM25. The mean statistical skill scores for rainfall are considerably improved in NCUM17.     

球载式下投国产北斗探空仪测风性能评估

基于球载式下投北斗探空仪测风观测试验,建立了针对下投式的测风试验评估方法.试验结果表明上升段北斗测风的准确度接近RS92探空仪的探测准确度要求,两者一致性较好;下降段RS92测风误差基本上与上升段的属于同一量级水平,下降初期测风数据在使用时需要做预处理或者有效控制;下降段BD探空仪测风误差与下降段RS92的基本相当,除了球炸初期外,基本上接近WMO的测量要求,此外初期的急速下降对导航定位测风提出了更高的技术要求.整体而言,球载式下投探空观测在时间上可以实现对原有的1次探空进行加密,在空间上可以增加1个区域的探测,并为对现有探空站网分布进行合理优化提供依据,具有良好的应用前景.