毁林带来大自然的惩罚

人类赖以生存的基础不外乎分为两大类:自然环境和社会环境。而自然环境是在人类社会出现以前就客观存在着,随着社会生产力的不断发展,自然环境在不断地被破坏。尤其是曾覆盖地球三分之二面积的森林,     

九峰山植被现状及其成因分析

介绍了九峰山的自然环境状况,详细的概述了九峰山植被的基本特征及其主要的植被类型,并在此基础上对其植被类型的成因作了进一步的思考和探讨,从而为人类认识和利用九峰山的植物资源提供理论依据。     

21世纪前1 5年四川省旱涝趋势预测

本世纪70年代以来,人类不断遭遇大范围自然灾害的困扰.其中,气候变化及其异常对人类生存环境和社会经济发展的影响愈来愈显著.人类社会正面临着自然环境恶化的严重威胁,如何预测它的未来演变趋势,有效防御自然灾害,已成为当今各国政府、科学家和社会公众关注的重大问题.     

离石市近40年气候变化特征及趋势分析

离石市地处吕梁山脉中段,黄河一级支流———三川河中游,受地理位置和大气环流的共同影响,冬寒夏暑,春暖秋凉,四季分明,属典型大陆性季风气候。近百年来随着社会经济的快速发展,人类活动对自然环境的影响超过了以前的数百数千年,而环境、气候对人类的繁衍生存至关重要,气候变化     

简论人类圈(Anthroposphere)在地球系统中的作用

工业革命后, 人类活动影响地球环境达到了空前的程度。近年提出的人类世 (anthropocene) 概念就是为表征地球系统演变进入了这一特殊的新纪元。然而, 人类活动并非单向地影响自然, 它在改变自然环境的同时, 环境变化也影响着人类行为, 迫使人类去适应自然变化, 改变生存方式。为更深入地表征人类活动与地球环境相互作用的这种特征, 作者讨论了在地球系统模式里引入“人类圈 (anthroposphere)” 的必要性以及由此带来的新的科学挑战, 并提出了构建包含人类圈的地球系统模式的一些思路。     

观测是研究和认识天气气候规律的基础──在新疆气象局纪念1994年世界气象日座谈会上的讲话

今天，全世界都在庆祝“世界气象日”，世界气象组织（WMO）执行理事会每年都要选择一个专题作为“气象日”纪念活动的主题。今年的主题是：观测天气和气候。一般说科学和技术的基础都依赖于精密的测量。气象观测，就是对大气中发生的现象及其变化过程进行系统、连续或阶段性的测量。目的就是为天气预报、气候分析预测、气象科学研究和国民经济的其它需要提供第一手的大气监测资料。有史以来，人类就一直在与自然环境的斗争中生存和发展的。而所有的自然环境中，气候是最基本的自然环境。长期以来，大量事实已经证明，对于气候资源的利用…     

葫芦岛市气象与海洋资源的开发利用

葫芦岛市地处渤海辽东湾西岸 ,自然环境优越 ,沿海资源丰富。葫芦岛建市以来 ,在传统海洋产业的开发利用方面取得一定成果的基础上 ,海水养殖业、海滨旅游业等新兴海洋产业也得到了蓬勃发展 ,为当地的社会、经济发展做出了贡献。但是 ,应当看到 ,人类活动造成的废气、废水、垃圾对大气和海洋的污染日益严重 ,大气和海洋环境越来越恶化 ;频繁发生的灾害性天气 ,带来了海洋灾害 ,在一定程度上影响和制约了海洋产业的发展。实践和经验证明 ,只要充分挖掘海域自然资源潜能 ,充分发挥气象与海洋产业的密切关系 ,就能变资源优势为经济优势 ;同时 ,…     

气候资源开发利用中的法律问题

气候资源是自然资源和自然环境的重要组成部分，旱涝等气候灾害严重影响国计民生，是国民经济建设中必须考虑的重要因素。因此，气候变化问题不仅引起世界科技界，而且已经引起世界各国政府的严重关注，成为影响一个国家或地区可持续发展的核心问题之一。气候资源作为一种重要的再生资源，只要不受破坏，可以一直利用，永不枯竭。但是，自工业革命以来，地球上人口剧增和生产规模的迅速扩大，对环境的破坏和对气候的影响越来越大。若不加以规划和控制，这种影响不但会破坏人类赖以生存的居住环境，也将影响社会和生产的发展。因此，增强气候意识，用法律手段来规范人类开发利用和保护气候资源的行为，有着重要的现实意义。     

防止气候恶化,优化人类生存的地球环境——气象科学面临的新挑战—纪念1991年世界气象日

在地球形成和发展的漫长历史过程中,气候环境经历了巨大的变动,人类是在被动适应自然环境的过程中生存和发展的。但是,世界工业革命以后,尤其是近百年来,地球上人口的剧增、科学技术水平的飞速提高以及生产建设规模的加速发展,使人类与自然的关系发生了根本的变化。许多观测事实与科学分析结果已经说明,现代人类活动对于几十年到近百年尺度的气候环境变化,     

自然环境和自然保护区

自然环境和自然资源是人类生存和社会繁荣的基础。由于长期自然历史变迁和人类活动的影响,自然环境日益恶化,自然资源日渐减少。特别是近几十年来,由于人类不合理地开发利用自然资源,使大自然的生态平衡失调,造成了严重的恶果。土地资源由于沙漠的侵吞,风、水的剥蚀,城市、交通的扩建,地下矿藏的开发等而日益减少。据联合国沙漠会议估计:世界上由于沙漠的侵吞每年约损失500—700万公顷的土地。森林是陆地上最大的生态系统,有“自然总调度”之称。十九世纪中叶全世界有55亿公顷森林,到目前只剩下28亿公顷,减少了一半。世界上每年毁     

Kinetics of the reactions of hydroxyl radicals with aliphatic ethers studied under simulated atmospheric conditions: Temperature dependences of the rate coefficients

Rate coefficients have been measured for the reactions of hydroxyl radicals with five aliphatic ethers over the temperature range 242–328 K. Competitive studies were carried out in an atmospheric flow reactor in which the hydroxyl radicals were generated by the photolysis of methyl nitrite in the presence of air containing nitric oxide. The reaction of OH with 2,3-dimethyl-butane was used as the reference reaction and the following Arrhenius parameters have been obtained for the reactions: OH+RORproducts:

Chemical characteristics of wet precipitation at an urban site of Guangzhou, South China

The pH variation and chemical characteristics of rainwater were investigated from January 2006 to December 2006 at an urban site of Guangzhou, South China. The rainwater was typically acidic with a volume-weighted mean pH value of 4.49, which ranged from 3.52 to 6.28. The volume-weighted mean equivalent concentration of components followed the order: SO₄²⁻ > Ca²⁺ > Cl⁻ > NH₄⁺ > Na⁺ > NO₃⁻ > K⁺ > Mg²⁺ > F⁻, indicating that SO₄²⁻, Cl⁻ and NO₃⁻ were the main anions, while Ca²⁺ and NH₄⁺, were the main cations. Ca²⁺ and NH₄⁺ were major neutralization constituents of the precipitation. Furthermore, correlation analysis and principal component analysis method were performed to identify possible common sources of major ions. Sources of the major ions were assessed based on enrichment factor method.     

A new criterion of relative homogeneity of climatological series

Summary When investigating, as a random sample, a series of differences between rather relatively homogeneous series of annual temperatures at two places, about 70 miles distant from one another it can be shown that the frequency distribution of the differences can be approximated by a normal distribution.Conversely, a normal distribution of the elements of the series of differences can be taken as a new criterion for the relative homogeneity of two series of average temperatures. This conclusion is verified by the agreement between other criteria for relative homogeneity and the new one.

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Zusammenfassung Die Häufigkeitsverteilung der Differenzen zweier synchroner Reihen von Jahrestemperaturen wurde untersucht. Sie stammten von zwei zirka 110 km voneinander entfernten Orten in einem einheitlichen (kohärenten) Klimagebiet der Atlantischen Küste der Vereinigten Staaten. Die Häufigkeitsverteilung zeigt eine ausgesprochen negative Schiefe (Abb. 1). Kritische Durchsicht der Differenzenreihe, wie sieJ. v. Hann empfiehlt, zeigte außer einigen mehr oder minder vielleicht unbedeutenden Inhomogenitäten zwei Perioden, die durch scharfe (entgegengesetzte) Diskontinuitäten von der übrigen Reihe abgetrennt erschienen. Die aufgezeigten Sprünge ließen sich im nachhinein durch in der Stationsgeschichte angeführte Aufstellungsänderungen der Instrumente erklären. Die Ausschaltung dieser gestörten Perioden reduzierte die 100jährige auf eine 85jährige Differenzreihe. Die von der letzteren abgeleitete Häufigkeitsverteilung ließ sich in zureichender Weise (Abb. 2) durch eine Gaußsche Kurve approximieren.Die vom Autor zur Prüfung relativer Homogenität verwendeten Kriterien (Abbe, Helmert, Met. Z. S. 1925, p. 482) ergaben das Resultat: nichthomogen im Falle der 100jährigen, und annähernd homogen für die 85jährige Reihe. Dieses Resultat führte zu der Annahme, daß das Problem umkehrbar wäre: wenn die Differenzenreihe sich durch eine Gaußsche Kurve annähernd darstellen läßt, können die ursprünglichen Temperaturreihen als relativ homogen angesehen werden. Weitere mathematisch-statistische Untersuchungen in dieser Richtung wären zu begrüßen, besonders wenn auch Quotientenreihen (Niederschlag) einbezogen würden.

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Résumé En étudiant une série de différences dérivées des séries plus ou moins relativement homogènes de températures annuelles à deux endroits l'un de l'autre à peu près 110 kms comme exemple de hasard, on peut démontrer que la distribution de la fréquence des différences peut être approximée par une distribution normale.Au contraire, une distribution normale des éléments des séries de différences pourrait être considérée comme un nouveau critérium de la homogénéité relative de deux séries de la température moyenne. Cette conclusion est vérifiée par l'accordance avec d'autres critériums.De plus, une continuation des études de ces problèmes au moyen de méthodes statistiques est désirable, en particulier, si l'on peut faire usage aussi de séries de quotients (précipitation).

     

Radiometrically determined skin temperature and scalar roughness to estimate surface heat flux. Part I: Parameterization of radiometric scalar roughness

A series of experiments carried out in a pasture field during a growing season, allowed a radiometric determination of the scalar roughness for sensible heatz _oh,r . The values ofz _oh,r are shown to vary over the range of 10^–1–10^–7m both diurnally and seasonally, and an existing theoretical model for the estimation of scalar roughness for sensible heat is found to be inappropriate for the precise estimation ofz _oh,r . To parameterizez _oh,r better, a multiple regression analysis was performed, with predictor candidates such as solar elevation, solar radiationR _s , leaf area index LAI, canopy height, the ratio of the solar radiation and the extraterrestrial radiationR _s /R _e , the ratio of the direct and the total solar radiationR _d /R _s , and the roughness Reynolds number among others. The best regression equation which usesR _s , LAI,R _s /R _e , andR _d /R _s is derived withr=0.75; with smaller numbers of predictors, values ofr tend to deteriorate gradually down tor=0.52 when only one predictor, LAI, was incorporated into the equation.     

Large-Eddy Simulation of Flow and Pollutant Transports in and Above Two-Dimensional Idealized Street Canyons

A large-eddy simulation (LES) model, using the one-equation subgrid-scale (SGS) parametrization, was developed to study the flow and pollutant transport in and above urban street canyons. Three identical two-dimensional (2D) street canyons of unity aspect ratio, each consisting of a ground-level area source of constant pollutant concentration, are evenly aligned in a cross-flow in the streamwise direction x. The flow falls into the skimming flow regime. A larger computational domain is adopted to accurately resolve the turbulence above roof level and its influence on the flow characteristics in the street canyons. The LES calculated statistics of wind and pollutant transports agree well with other field, laboratory and modelling results available in the literature. The maximum wind velocity standard deviations σ _i in the streamwise (σ _u ), spanwise (σ _v ) and vertical (σ _w ) directions are located near the roof-level windward corners. Moreover, a second σ _w peak is found at z ≈ 1.5h (h is the building height) over the street canyons. Normalizing σ _i by the local friction velocity u _*, it is found that σ _u /u _* ≈ 1.8, σ _v /u _* ≈ 1.3 and σ _w /u _* ≈ 1.25 exhibiting rather uniform values in the urban roughness sublayer. Quadrant analysis of the vertical momentum flux u′′w′′ shows that, while the inward and outward interactions are small, the sweeps and ejections dominate the momentum transport over the street canyons. In the x direction, the two-point correlations of velocity R _v,x and R _w,x drop to zero at a separation larger than h but R _u,x (= 0.2) persists even at a separation of half the domain size. Partitioning the convective transfer coefficient Ω _T of pollutant into its removal and re-entry components, an increasing pollutant re-entrainment from 26.3 to 43.3% in the x direction is revealed, suggesting the impact of background pollutant on the air quality in street canyons.     

基于风廓线雷达的对流边界层高度的确定

大气边界层高度对于天气、气候和大气污染研究是一个至关重要的参量。对流边界层(Convective Boundary Layer,CBL)顶部的夹卷过程造成温度和湿度垂直梯度增强,导致这一层的折射率结构常数C■变高。C■的这种垂直分布特征经常被用来定位出CBL高度Z_i。本文利用2010年7—8月天津大港的风廓线雷达数据推断出CBL高度Z_i,对于多重C■峰值或不明确的C■峰值,本文改进了对Z_i的测定,分别讨论了C■最大后向散射法与C■和垂直速度方差(σ■)相结合的新方法的适用性。研究显示:(1)C■廓线具有单峰时,最大后向散射强度法能正确估计CBL高度,这种情况往往对应的是晴天。CBL上存在的残留层或云层引起的温湿起伏变化导致C■廓线具有双峰甚至多峰时,最大后向散射强度法可能会错误估计CBL高度;(2)C■和σ■结合的方法不仅与晴天时C■最大后向散射法有较好的一致性,而且可以将CBL造成的C■峰值从云层造成的C■峰值中区分出来,从而正确估计CBL高度;(3)一般而言,对流边界层中存在有明显的、破碎或者分散不明显的云时,C■和σ■结合的方法都能较好地识别出CBL对应的C■峰值。但由于边界层中的情况极为复杂,C■和σ■结合法也会因不同的原因而错误估计CBL高度。     

Über den Einfluß der Witterung auf den Schwefelstoffwechsel von Kaninchen

Zusammenfassung Während vier Monaten wurde der Harn einer Anzahl von Kaninchen, die radioaktiv markiertes Natriumsulfat (Na ₂ S ³⁵ O ₄) erhalten hatten, täglich auf seine Aktivität geprüft. Es ergab sich, daß an gewissen Tagen deutlich mehr Schwefel ausgeschieden wurde als normalerweise. Die Analyse führte zu der Feststellung, daß es sich durchwegs um Kaltfronttage handelte, die sowohl vor wie nach dem Durchzug polare Luftkörper aufwiesen; die fünf Kaltfronten mit tropischer Ausgangslage dagegen hatten keine biotrope Wirkung auf den Schwefelstoffwechsel.

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Summary During four months the urine of a certain number of rabbits, which had received radioactively marked sodium-sulphate (Na ₂ S ³⁵ O ₄), has been examined daily as to its activity. It resulted that on certain days the secretion of sulphur was distinctly above the normal value. This was the case on all cold front days, which had a polar air mass before as well as after their passage. The five cold fronts following a tropical air mass on the other hand produced no biotropic effect on the sulphur metabolism.

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Résumé L'urine d'un certain nombre de lapins, qui avaient reçu du sodium sulfaté (Na ₂ S ³⁵ O ₄) à marquage radio-actif a été examiné chaque jour quant à son activité. Il s'est avéré qu' à certains jours la sécrétion de soufre était remarquablement au-dessus de la valeur ordinaire. L'analyse a montré qu' à ces jours passaient des fronts froids qui été précédés et suivis de masses d'air polaire; en revanche, les cinq fronts froids qui, suivaient des masses d'air tropical n'avaient aucune influence biotropique sur le métabolisme sulfureux.

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Mit 4 Textabbildungen     

On Transpiration and Soil Moisture Content Sensitivity to Soil Hydrophysical Data

Sensitivity of evapotranspiration E and root zone soil moisture content θ to the parameterization of soil water retention Ψ(θ) and soil water conductivity K(Ψ), as well as to the definition of field capacity soil moisture content, is investigated by comparing Psi1-PMSURF and Theta-PMSURF models. The core of PMSURF (Penman–Monteith Surface Fluxes) consists of a 3-layer soil moisture prediction module based on Richard’s equation in combination with the Penman–Monteith concept for estimating turbulent heat fluxes. Psi1- PMSURF and Theta-PMSURF differ only in the parameterization of the moisture availability function F_ma. In Psi1,F_ma is parameterized by using Ψ(θ) and K(Ψ) hydrophysical functions; in Theta, F_ma is parameterized by using hydrophysical parameters: the field capacity θ_f and wilting point θ_w soil moisture contents. Both Psi1 and Theta are based on using soil hydrophysical data, that is, there is no conceptual difference between them in the parameterization of E even if in Psi1F_ma depends on 12 parameters, while in Theta only on two soil/vegetation parameters. Sensitivity tests are performed using the Cabauw dataset. Three soil datasets are used: the vG (van Genuchten), CH/vG (Clapp and Hornberger/van Genuchten) and CH/PILPS (Clapp and Hornberger/Project for Intercomparison of Land-surface Parameterization Schemes) datasets. The vG dataset is used in van Genuchten’s parameterization, while in Clapp and Hornberger’s the CH/vG and CH/PILPS datasets are used. It is found that the consistency of soil hydrophysical data in the simulation of transpiration is quite important. The annual sum of E obtained by Psi1E^Psi1, differs from the annual sum of E obtained by Theta, E^Theta, because of the inconsistency between the fitting parameters of Ψ(θ) and K(Ψ) and the θ_f, and not because of the differencies in the parameterization of F_ma. Further, θ_f can be estimated not only on the basis of using soil hydrophysical functions (the θ_f so obtained is θ^Soil_f) but also on the basis of analysing the transpiration process (the θ_fso obtained is θ^tr_f). θ^tr_f values estimated from the condition E^Theta ≈ E^Psi1 are in acceptable accordance with the θ^Soil_f values proposed by Wösten and co-workers. The results are useful in optimizing the parameterization of transpiration in land-surface schemes.