Application of the Physical Quantity Field Evolution under Numerical Model in Precipitation Forecast of Yantai

[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.

Comparative Analysis on Physical Quantity Diagnosis and Wind Profile Radar Data of Two Heavy Rainfalls

[ Objective] The research aimed to contrast physical quantity diagnosis and wind profile radar data of two heavy rainfalls. [ Method ] From circulation background, physical quantity field and wind profile radar data, we analyzed two big rainstorm weather processes （8 -9 July and August 10） in Lianyungang City in 2012. [ Result] Rainstorm generation was related to favorable large-scale circulation situation. The first-stage precipitation during 8 -9 July was warm-zone precipitation, and the precipitation at the second stage was triggered by shear line. Precipitation on August 10 was generated by typhoon low-pressure inverted trough and cold air. Sufficient water vapor content and strong water vapor transportation were favorable for generation of the heavy precipitation. Suction effect by divergence at high layer and convergence at middle and low layers was favorable for maintenance of the strong ascending motion. Occurrence of the heavy precipitation must have ascending motion condition. But it was not that the stronger the ascending motion, the stronger the rainfall intensity. Kindex and θse500 -θse 850 were closely related to rainstorm occurrence. Horizontal wind data of the wind profile radar provided fine structure of the atmospheric horizontal motion at vertical direction, could clearly display vertical structure of the wind field in rainstorm process, and directly reflected change characteristics of the wind field in precipitation process. [ Conclusion] The research could provide reference for future forecast work.

Threshold Analysis of Sounding Physical Quantities of Rainstorm in Southwest China

Using physical quantities calculated by 16 radiosonde stations of Southwest China during 2010-2015,nine kinds of physical quantities with certain representational significance in water vapor,thermal and dynamic conditions were selected.Via box-plot,statistical analysis was conducted,and thresholds of sounding physical quantities of rainstorm in Southwest China were obtained,which could provide certain reference for further improving the rainstorm forecast in Southwest China.

医学科技期刊物理量(physical quantity)与缩写

用于定量地扫描物理现象的量.即科学技术领域里使用的表示长度、质量、时间、电流、热力学温度、物质的量和发光强度的量。使用的单位应是法定计量单位。两分钟→2min,一秒钟→1 s,三小时→3h,4天→4d,1国际单位用IU。国际代号不用于无数字的文句中,如每天不能用每d,但每天10mg应写为10mg/d,次/秒→次/s。

Unleashing the Power of Information Theory: Enhancing Accuracy in Modeling Physical Phenomena

When building a model of a physical phenomenon or process, scientists face an inevitable compromise between the simplicity of the model (qualitative-quantitative set of variables) and its accuracy. For hundreds of years, the visual simplicity of a law testified to the genius and depth of the physical thinking of the scientist who proposed it. Currently, the desire for a deeper physical understanding of the surrounding world and newly discovered physical phenomena motivates researchers to increase the number of variables considered in a model. This direction leads to an increased probability of choosing an inaccurate or even erroneous model. This study describes a method for estimating the limit of measurement accuracy, taking into account the stage of model building in terms of storage, transmission, processing and use of information by the observer. This limit, due to the finite amount of information stored in the model, allows you to select the optimal number of variables for the best reproduction of the observed object and calculate the exact values of the threshold discrepancy between the model and the phenomenon under study in measurement theory. We consider two examples: measurement of the speed of sound and measurement of physical constants.

SEPARATING COUPLED PHYSIC QUANTITY BYPOTENTIAL OPERATOR

In the present paper, using the method of separating coupled physic quantity bypotential operator, we derive two special minmum principles in coupled thermoelastodynamics.

An analogical study of wave equations,physical quantities,conservation and reciprocity equations between electromagnetic and elastic waves

This paper presents an analogical study between electromagnetic and elastic wave fields,with a one-to-one correspondence principle established regarding the basic wave equations,the physical quantities and the differential operations.Using the electromagnetic-to-elastic substitution,the analogous relations of the conservation laws of energy and momentum are investigated between these two physical fields.Moreover,the energy-based and momentum-based reciprocity theorems for an elastic wave are also derived in the time-harmonic state,which describe the interaction between two elastic wave systems from the perspectives of energy and momentum,respectively.The theoretical results obtained in this analysis can not only improve our understanding of the similarities of these two linear systems,but also find potential applications in relevant fields such as medical imaging,non-destructive evaluation,acoustic microscopy,seismology and exploratory geophysics.

An Ordering Policy for Deteriorating Items with Time-Dependent Quadratic Demand and Salvage Value under Permissible Delay in Payment

The article deals with an economic order quantity (EOQ) inventory model for deteriorating items in which the supplier provides the purchaser a permissible delay in payment. This is so when deterioration of units in the inventory is subject to constant deterioration rate, demand rate is quadratic function of time and salvage value is associated with the deteriorated units. Shortages in the system are not allowed to occur. A mathematical formulation is developed when the supplier offers a permissible delay period to the customers under two circumstances: 1) when delay period is less than the cycle of time;and 2) when delay period is greater than the cycle of time. The method is suitable for the items like state-of-the-art aircrafts, super computers, laptops, android mobiles, seasonal items and machines and their spare parts. A solution procedure algorithm is given for finding the optimal order quantity which minimizes the total cost of an inventory system. The article includes numerical examples to support the effectiveness of the developed model. Finally, sensitivity analysis on some parameters on optimal solution is provided.

Improvement of Physical and Biological Quality of Soil in a Sugarcane Plantation through the Management of Organic Matter Input

Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology （earthworms） and physical quality （aggregate stability, macroporosity and infiltration rate）. There were i 5 treatment combinations tested. The first factor is the type of organic matter： （1） cattle manure （CM）, （2） filter cake （FC）, （3） sugarcane trash （ST）, （4） a mixture ofCM ＋ FC and （5） a mixture of CM ＋ ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment （without organic matter input）. The result of this research showed that the highest population density of earthworms was found in the treatment of ST （78 individuals/m2） and a mixture of CM ＋ ST （84 individuals/m2）. The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity （from r = 0.683 to r = 0.606） and infiltration rate （from r = 0.669 to r = 0.756）. The results of this study suggest a mixture of CM ＋ ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.

Short-Term Financing of Economic Order Quantity （EOQ） Inventory Model With Probabilistic Quality

In this paper, the classical economic order quantity （EOQ） inventory model assumption that all items of a certain product received from a supplier are of perfect quality is relaxed. Another basic assumption that the payment for the items is made at the beginning of the inventory cycle when they are received is also eased. We consider an inventory situation where items received from the supplier are of two types of quality, perfect and imperfect, and a short deferral in payment is allowed. The split between perfect and imperfect quality items is assumed to follow a known probability distribution. Both qualities of items have continuous demands, and items of imperfect quality are sold at a discount. A mathematical model is developed using the net present value of all cash flows involved in the inventory cycle. A numerical method for obtaining the optimal order quantity is presented, and the impact of the short-term financing is analyzed. An example is presented to validate the equations and illustrate the results.

川西高原冰雹时空分布特征及大冰雹环境条件分析

选取2001—2016年川西高原31个县市气象站逐月冰雹日、3个探空站资料及ERA5逐小时再分析资料,分析川西高原冰雹时空分布特征及冰雹发生的天气背景和环境条件。结果表明:(1)近16 a川西高原冰雹日数总体呈减少趋势,高海拔降雹次数多于较低海拔地区。降雹频率分布曲线呈双峰偏态型,阿坝州的峰值出现在5月和9月,甘孜州出现在6月和9月。降雹主要发生时段为11—21时,占比95.5%,峰值出现在15时和17时。冰雹直径<5 mm冰雹占年降雹的72%以上。(2)连续冰雹天气的发生多伴随有高原低值系统的东移,黄淮低涡西侧的切变是影响夏季阿坝地区的重要天气系统之一。不同季节阿坝北部的大冰雹天气均是在高原低值系统的影响下发生,春、夏季大冰雹个例受明显的冷空气或冷平流的影响。(3)大冰雹个例中,-20℃层高度为7.2~8.6 km,0℃层高度距离地面4 km左右,对流有效位能CAPE≥980 J·kg^(-1)。无论春夏还是秋季,红原大冰雹个例的中低层温差(T600~400 hPa)≥21℃且600~400 hPa垂直风切变达到15~21 m·s^(-1),有利于形成高度组织化的对流风暴。

论齿轮样板

齿轮样板是齿轮参数量值的标准实物载体,用于将齿轮国家测量标准所复现的量值传递到各级齿轮测量仪器上,从而实现齿轮测量的准确性和一致性,保证齿轮产品质量。全面概述了齿轮样板起源及其发展历程;详细论述了齿轮样板的种类、结构及特点、齿轮样板的测量技术及装置、齿轮样板的国际比对、未来的发展与展望。齿轮样板迄今已历经九十多年发展,其种类在不断丰富、尺度不断延伸、复杂度不断简化,作为一种“有形”的实物量具,目前仍不可替代。未来随着“无形”的虚拟仿真测量技术发展,对“有形”实物样板的依赖将可以减弱,“无形”的技术将可能成为量值传递的新模式。

宁夏2018年8月20—21日区域性暴雨环流背景和物理量因子分析

【目的】利用常规观测资料、探空资料和NCEP/NCAR 1°×1°的逐6 h再分析资料,对2018年8月20—21日宁夏区域性暴雨产生的环流背景和物理量因子进行分析,为当地暴雨预报提供参考。【方法】通过环流分析和物理量诊断方法,对此次暴雨产生的环流背景、影响因子、水汽、热力、动力条件等物理量因子进行分析。【结果】结果表明:此次降水过程是在欧亚“两槽两脊”形势背景下,配合中低层低涡、切变线产生的。700 hPa水汽输送是主要水汽条件。700 hPa以下,36°~39°N为强辐合区,强辐合区上空对应辐散区,且辐合中心略向北倾斜,有利于上下抽吸,增强上升运动。水平方向上辐合区、辐散区成对紧邻出现,有利于增强水平辐合辐散,以及上升运动的维持。西北-东南向高能舌的持续存在,为强对流天气提供了充足不稳定能量。【结论】有利的环流背景,700 hPa充足的水汽,配合一定的动力、热力条件造成了此次暴雨天气的生成、发展。

电机学中的一些“反常”现象及其成因分析

描述了电机学中的一些“反常”现象,分析了这些现象的成因,并用简明的语言进行归纳,为相关领域的研究人员提供一定参考。

宁夏两次夏季典型暴雨过程成因对比分析

利用自动气象站站点实况和ECMWF ERA5的逐时再分析资料,通过环流分析和物理量诊断方法,对比了2017年6月4日和2019年8月2日宁夏区域性暴雨强降水区域、环流背景、影响系统和物理量因子的共性和差异。结果表明:后者累积降水量和最大小时雨强均比前者大;2017年6月4日,宁夏处于东高西低的环流形势中,强降水出现在低空急流的左前方、低空切变线的右前方(即宁夏中北部),稳定维持的地面中尺度辐合线触发了局地强降水;2019年8月2日暴雨过程出现在宁夏南北两头,是两槽一脊环流背景下,由500 hPa冷涡、冷槽和700 hPa低槽、切变、低空急流共同造成,是一次典型的强对流单体导致的暴雨过程;2019年8月2日短时强降水过程比湿、CAPE、ZH 0℃高度、-20℃层高度数值较大;两次短时强降水过程沙氏指数为正;2017年6月4日LI为正值,2019年8月2日LI为负值;2017年6月4日850 hPa与500 hPa假相当位温差为负值,2019年8月2日为正值;二者200 hPa、700 hPa为辐散,850 hPa为辐合,2019年8月2日200 hPa辐散中心强度大于2017年6月4日,而700 hPa辐散中心强度和850 hPa辐合中心强度反之。

水土保持生态产品价值实现理论探索

水土保持生态产品价值实现具有重要意义。尝试界定水土保持生态产品概念,对产品进行分类,探索构建水土保持生态产品价值核算方法,分析水土保持生态产品价值转化路径,梳理浙江省安吉县石门坑清洁小流域水土保持生态产品价值转化经验,提出加快推动水土保持生态产品价值实现的对策建议,以期为推动水土保持高质量发展和建设美丽中国提供有益参考。

基于蓄热式固定床气化装置的木质生物质固废气化CFD模拟

基于计算流体力学-稠密离散相模型,建立新型蓄热式气化装置的数值模拟模型,根据上吸式固定床气化特性优化了前处理设置,研究不同过量空气系数下炉内流体流速、压力、温度与组分的分布,分析炉内各组分质量分数在不同时刻及过量空气系数下的分布及演化规律。研究表明,颗粒床层为影响流体流速、压降的主要因素,流体流经床层产生了50~75 Pa的压降。炉内温度场呈现出明显的干燥-热解-还原氧化分区,各工况的温度曲线几乎重叠,大致存在4个拐点。在低过量空气系数区间,气化剂流率的提升对燃气组分影响不大。气化装置的设计有利于提升燃气中H2的质量分数及CO/CO_(2)的质量分数之比,有效提升了燃气热值。

基于“配料法”的渠江流域短时强降水中尺度概念模型及物理量配置

本文利用2010—2020年高空和地面观测资料,基于流型辨识法和配料法,建立了渠江流域短时强降水概念模型,对抬升条件、水汽条件和不稳定条件等物理量特征进行定量分析。结果表明:(1)渠江流域短时强降水按环流形势可分为3类6型,即副高边缘低槽类、高空低槽类、副高控制类三个大类,其中副高边缘低槽类分为低涡切变型、低空急流型和混合型,高空低槽类分为冷锋低槽型和短波槽型,副高控制类只有高空冷平流型。(2)副高边缘低槽类主要集中出现在6—9月,是发生最多的一类,占总个例数的64.5%;高空低槽类是3—5月和10—11月短时强降水的主要类别;副高控制类主要出现在8月,仅占1.7%。(3)副高边缘低槽类短时强降水具有范围大、时间长、降雨强的特点,高空低槽类短时强降水过程累计降水量小于副高边缘型,副高控制类短时强降水范围一般不大,但局地性强,通常还伴有雷电大风等对流性天气。(4)渠江流域短时强降水各类型的中尺度物理量阈值对于提高区域强降水预报水平具有一定的参考价值。

基于数据驱动相似度方法的风电场站动态等值建模研究

针对大型集中式风电场站中风电单元众多、运行工况多变、集电网及拓扑接线繁杂的特点,提出一种数据驱动相似度方法,实现对大型集中式风电场站的等值建模。首先,引入相似度来表征风电发电单元运行状态中的数据特征,并通过相似度,以数据驱动方式实现风电发电单元聚类分群;其次,对同一集群的发电单元进行聚合,获得等值机组的等值参数,并最终得到风电场等值模型;最后,以广东省某海上风电场为实例,对所提方法进行仿真与验证。研究结果表明,该方法能有效提升风电场的建模效率和模型精度。

2021年宁夏两次持续沙尘重污染天气对比分析

为探究气象条件变化对宁夏沙尘重污染天气过程的影响特征,利用常规气象观测数据、NCEP再分析资料及环境空气质量数据,选取2021年1月11-14日和2021年3月14-19日两次沙尘重污染天气(分别简称“0113”过程和“0315”过程)为研究对象,基于天气形势、后向轨迹模拟及物理量场诊断等方法,对比两次过程影响系统及传输轨迹,探讨形成和维持机制.结果表明:①“0113”过程主要影响宁夏北部四市,“0315”过程影响整个宁夏,两次沙尘过程中重度及以上污染平均持续时间分别为35.0和105.2h,沙尘污染暴发阶段PM_(10)浓度平均值分别为1735和5265μg/m3.②“0113”过程为一次强度一般的锋面过境引起的沙尘重污染天气,稳定少动的青藏高压与其北侧蒙古热低压之间形成显著的气压梯度带,高空脊前多股强西北气流引起动量下传,使宁夏及上游地区大风将沙尘输送至宁夏造成重污染;“0315”过程为一次较强的典型锋面过境及蒙古气旋造成的持续沙尘重污染天气,蒙古冷高压受强盛蒙古气旋和青藏高原热低压夹击稳定少动,其西南、东南及东部与两个热低压形成气压梯度带,加之受地面冷锋过境影响,宁夏及周边地区多方向大风将沙尘向宁夏上空输送造成“0315”过程较“0113”过程污染更严重.③两次过程中沙尘均为境外和境内同时输送,“0113”过程为西北和偏西路径,传输距离长且高度较低;“0315”过程为西北、偏北和偏东路径,传输距离短且高度较高.④“0315”过程中蒙古国及我国新疆-甘肃一带负水平螺旋度中心值为“0113”过程的1.75倍,较强的辐合上升运动和西风气流将沙尘持续向宁夏上空输送并与本地沙尘叠加,上升和下沉运动交替使沙尘长时间悬浮于空中,而“0113”过程受多股强下沉气流造成沙尘迅速沉降至地面,污染快速减弱.研究显示:冷锋和蒙古气旋是宁夏沙尘重污染天气的主要影响系统,当有只冷锋过境时,上游沙尘传输高度低,到达宁夏上空沙尘粒子相对少,使宁夏沙尘重污染天气持续时间短且强度相对较弱;当伴有蒙古气旋活动时,沙尘传输高度高,到达宁夏上空沙尘粒子多,使宁夏沙尘重污染天气持续时间长、影响范围广且强度较强.