作物绿叶面积、叶功能对降雨的影响

作物绿叶面积、叶功能对降雨的影响杨关生刘献张青海（汝州市林汝镇农技站·４６７５００）（汝州市气象局）统计汝州１９５７～１９９２年３６年气象资料和作物叶面积、叶功能年变化，结果发现，降水年分布规律与作物叶面积、叶功能年变化规律吻合。立春后，气温回升，大...     

我国农业气象业务引入作物生长模型的前景

国外作物生长模型已广泛应用于农业生产及其相关领域。我国作物生长模型的应用研究也日益成熟。目前，正从研究阶段向业务应用推广阶段转变。为了阐述作物生长模型在农业气象业务中的应用前景，以WOFOST模型为例，简要介绍了国外作物生长模型的核心模块、主要功能和应用现状。在此基础上，分析了我国现行气象业务可为开展作物生长模型应用提供的数据支持，存在的问题以及解决方案。指出作物生长模型在拓展当前我国农业气象业务领域和提升农业气象服务水平等方面前景广阔。     

O_3浓度变化对我国主要作物产量的可能影响

该文介绍了Ｏ＿３浓度变化对农作物的影响机制，如Ｏ＿３对作物光合与呼吸、生理生化过程和代谢物质、细胞透性、体内各类醇、组织器官以及其它功能的影响，根据美国ＮＣＬＡＮ近１０年的试验资料建立的Ｏ＿３浓度与作物产量的准线性关系，推算和评价了Ｏ＿３浓度变化对我国主要作物产量的可能影响。     

自动农业气象观测系统功能与设计

根据现代农业气象业务需求,提出了可视化、实时性、远程控制的自动农业气象观测系统技术思路、设计原则,并设计了系统的硬件和软件架构及自动化观测的实现方法。该系统具有作物生长、农田气象要素观测及环境监控功能,可实现作物发育期、株高、盖度等的自动观测,还可实现农田主要农业气象灾害实时监测。该文利用三维空间模拟技术初步确定了CCD (charge-coupled device) 传感器的技术指标;提出利用图像判别技术,结合作物生长特征及农业气象指标,实现作物发育期自动判别;利用摄影测量学技术,采用动态跟踪法实现作物株高自动化观测;提出了作物盖度的计算方法和通过研究作物盖度与密度、叶面积指数的关系,解决作物种植密度和叶面积指数自动观测的技术思路。该系统模仿人工观测原理,将图像处理和摄影测量学等技术引入农业气象自动观测中,基本上可以满足农业气象观测的主要任务的实时性、可视化和自动化需求。     

O3浓度变化对我国主要作物产量的可能影响

该文介绍了Ｏ３浓度变化对农作物的影响机制，对Ｏ３对作物光合与呼吸、生理生化过程和代谢物质、细胞透性、体内各类酶、组织器官以及其它功能的影响，根据美国ＮＣＬＡＮ近１０年的试验资料建立的Ｏ３浓度与作物产量的准线性关系，推算和评价了Ｏ３浓度变化对我国主要作物产量的可能影响。     

中国农业气象模式(CAMM1.0)构建与应用

为发展适宜中国区域农业种植特点的农业气象模式,基于国外作物生长模拟方法,通过模式机理过程改进或重构以及应用方式革新,建立了中国农业气象模式（Chinese AgroMeteorological Model version 1.0,CAMM1.0）。CAMM1.0利用平均温度和土壤水分改进了作物发育进程模式,利用土壤水分改进了作物叶片光合作用、干物质分配和叶面积扩展过程模式,通过蒸发比法扩展了作物蒸散过程模式;自主建立了基于发育进程的冬小麦株高、基于遥感信息的作物灌溉、遥感数据同化、作物长势与灾害评价等模式。基于互联网技术构造了实时运转平台,主要功能包括作物生长过程实时常规模拟与用户个性化定制模拟。CAMM1.0的部分子模式采用多种方法构造,便于多模式集成。CAMM1.0对作物发育进程、光合过程、株高的模拟效果较好,但对土壤水分变化过程的拟合略差,模拟产量略偏低。CAMM1.0评价淮河流域夏玉米年际干旱减弱而涝渍增加的趋势与实际基本相符。     

利用扫描仪测量作物叶面积的模式选择与实现技术

根据低成本、高精度、方便快捷测量作物叶面积的实际需要,利用常见的计算机和扫描仪设备,通过选择不同的扫描模式,采用有底板与无底板、有压膜与无压膜以及不同叶状样本的测量方法比较得出,各种处理测量误差都很小,但以无底板、无压膜的300dpi灰阶法最佳,测量误差仅为0.4‰,并基于计算机图像处理技术研制了相应的扫描仪测量作物叶面积软件,实现了作物叶面积测量、参数选择、图像和数据显示存储调用、数据统计、叶面积指数计算等功能。     

金针菜产量与气象因子的关系

金针菜是多年生宿根作物,其营养丰窗,含有糖类、蛋白质、氨基酸、钙、磷等。并具有药用价值,有止血、消炎、利尿、清热等功能。还含有秋水仙碱、冬门素和萱草根索等,对产妇有增加奶汁分泌的功能。江     

基于WebGIS的农业气象业务平台的设计与实现

农业气象业务平台的建设对于保障农业由传统农业向高产、优质、高效、生态、安全和可持续发展的现代农业加快转变具有积极意义。以浙江全省地面气象观测网数据为基础,结合精细网格化气象要素预报产品、农业气象诊断指标、作物分布信息,研发了以气象指数为主的14类农业气象灾害监测预警指标、6类作物农用天气预报指标和水稻等作物生长发育动态诊断模型;基于B/S结构和ASP.NET开发平台,遵循SOA架构原则,采用C#、Java等计算机语言研制了基于WebGIS的浙江省省、市、县三级应用的农业气象业务平台。该平台集成了气象学、统计学、农学等研究领域的算法和模型进行跨领域数据分析,具备强大的定量及定性分析功能,平台操作简便、功能灵活,且支持自主构建评价体系,目前已经在浙江省省、市、县三级气象部门推广应用。     

基于双波段图像的玉米长势自动观测方法研究

利用一款改装后具有近红外图像拍摄功能的民用相机和同型号未经改装的可见光拍摄像机监测作物的整个生长过程,根据作物和土壤在近红外和可见光图像中的敏感性不同,利用图像处理算法获取作物覆盖度(Ccp),并与人工观测的作物生长特征量进行相关分析。通过在中国气象科学院固城试验站开展的玉米观测试验,基于自动观测玉米图像获取的Ccp与人工观测植株高度(近红外R~2=0.9276,可见光R~2=0.8491)、叶面积指数(近红外R~2=0.9535,可见光R~2=0.8822)、干物质重量(近红外R~2=0.9497,可见光R~2=0.7708)等之间具有很高的相关性,同样表明利用近红外相机获取的玉米图像比可见光相机获取的图像能更好地反映玉米的生长特征。     

Tropical cyclones and polar lows: Velocity,size, and energy scales,and relation to the 26°C cyclone origin criteria

The goal of this paper is to quantitatively formulate some necessary conditions for the development of intense atmospheric vortices. Specifically, these criteria are discussed for tropical cyclones (TC) and polar lows (PL) by using bulk formulas for fluxes of momentum, sensible heating, and latent heating between the ocean and the atmosphere. The velocity scale is used in two forms: (1) as expressed through the buoyancy flux b and the Coriolis parameter l_c for rotating fluids convection, and (2) as expressed with the cube of velocity times the drag coefficient through the formula for total kinetic energy dissipation in the atmospheric boundary layer. In the quasistationary case the dissipation equals the generation of the energy. In both cases the velocity scale can be expressed through temperature and humidity differences between the ocean and the atmosphere in terms of the reduced gravity, and both forms produce quite comparable velocity scales. Using parameters b and l_c, we can form scales of the area and, by adding the mass of a unit air column, a scale of the total kinetic energy as well. These scales nicely explain the much smaller size of a PL, as compared to a TC, and the total kinetic energy of a TC is of the order 10¹⁸-10¹⁹ J. It will be shown that wind of 33 m s^-1 is produced when the total enthalpy fluxes between the ocean and the atmosphere are about 700 W m^-2 for a TC and 1700 W m^-2 for a PL, in association with the much larger role of the latent heat in the first case and the stricter geostrophic constraints and larger static stability in the second case. This replaces the mystical role of 26^oC as a criterion for TC origin. The buoyancy flux, a product of the reduced gravity and the wind speed, together with the atmospheric static stability, determines the rate of the penetrating convection. It is known from the observations that the formation time for a PL reaching an altitude of 5--6 km can be only a few hours, and a day, or even half a day, for a TC reaching 15--18 km. These two facts allow us to construct curves on the plane of T^s and ΔT=T_s-T_a to determine possibilities for forming an intense vortex. Here, T_a is the atmospheric temperature at the height z=10 m. A PL should have ΔT>20^oC in accordance with the observations and numerical simulations. The conditions for a TC are not so straightforward but our diagram shows that the temperature difference of a few degrees, or possibly even a fraction of a degree, might be sufficient for TC development for a range of static stabilities and development times.     

The impact of compensatory measures on public support for carbon taxation: an experimental study in Sweden

This study aims at better understanding how, and to what extent, perceptions of a policy instrument’s distributional effects impact on policy support, focusing on the case of CO₂ taxes on petrol in Sweden. Through a large-scale (N?=?5000) randomized survey experiment with a 2?×?3 factorial design, the extent to which perceptions of fairness determine attitudes to a suggested increase of the Swedish CO₂ tax is explored. Furthermore, the study considers whether these effects change with the level of the suggested tax increase, as well as whether negative sentiments can be alleviated by combining it with a compensatory measure in the shape of a simultaneous income tax cut financed by the revenues from the tax increase. The results show that a higher tax increase is both viewed as more unfair and enjoys weaker support. Furthermore, compensatory measures can be a powerful policy design tool to increase perceptions of the policy as fair, but the effect of compensation on policy support is conditioned by the individual’s left–right ideological position. Whereas people self-identifying to the right react favourably to compensatory measures, people self-identifying to the left become less supportive of a tax increase when combined with a simultaneous cut in income taxes.

Key policy insights

• Perceptions of fairness are highly important for explaining public support for climate policy tools, specifically CO₂ taxes.

• Compensatory measures can be a powerful policy design tool to increase perceptions of the policy as less unfair.

• However, the effect of compensatory measures on policy support is conditioned by ideological position, and only successful among people to the ideological right.

• In contexts dominated by right-wing ideals, a combination of a tax and a compensatory scheme may be a successful route forward towards increased climate policy support.

• In left-oriented contexts the results imply that a CO₂ tax without compensation seems more likely to increase support.

     

Radar measurements of integral parameters of hailstorms used on hail suppression projects

The exact quantitative estimation of hailstorm precipitation intensity, allowing determining successfully the crop hail damage, is extremely necessary while carrying out of programs of experimental researches of the hail clouds as well as at realization of operative projects on hail suppression. On the other hand, the possibility of obtaining a trustworthy information about changes of hailfall intensity during cloud seeding operations enables to judge more objectively about seeding effect and to make a decision about its beginning and termination. Just because of such a parameter, the kinetic energy of hailfalls presents a great interest for the researchers. As it is known, measuring the kinetic energy of hailfalls is carried out both directly by ground network of hailpads, and by radar methods. The accuracy of the radar methods of the hail kinetic energy measurement strongly depends not only on the choice of an optimum formula for calculation but also on the algorithm used for separating hail and rain parts of radar echo and on the way it was used in the hail–rain mixture zone of precipitation.The method of calculating the kinetic energy of the hailfalls, based on empirical dependence of hail probability P_h on a height of a zone of a radar echo with a reflectivity of 45 dBZ above a level of zero isotherm ΔH₄₅, is offered in the given work. The algorithm of separating hail and rain parts of a radar echo and the way it was applied in a hail–rain mixture zone is described. The examples of hail streaks in contours of radar reflectivity and in isopleths of hail kinetic energy obtained using the given algorithm are shown.In Mendoza province (Argentina), a hail suppression project (1993–1997) for the analysis of the vertical structure of a radar echo with Z_max > 45 dBZ, such new parameter is an integral altitude, was used. This dimensionless parameter is most sensitive to such a condition of radar echo when all four contours of increased reflectivity Z₄₅, Z₅₅, Z₆₅, and Z₇₅ synchronously reach the maximal values. The analysis of time distributions of the main radar parameters of hailstorms on a background of values of integral altitude is resulted. It is shown that local hailfall maximum intensities on the ground are observed after the achievement of maximum integral altitude with a certain delay. It enables to predict zones of the greatest hail damage in a mode of radar observation.     

Classification of Vertical Wind Speed Profiles Observed Above a Sloping Forest at Nighttime Using the Bulk Richardson Number

Wind speed profiles above a forest canopy relate to scalar exchange between the forest canopy and the atmosphere. Many studies have reported that vertical wind speed profiles above a relatively flat forest can be classified by a stability index developed assuming wind flow above a flat plane. However, can such a stability index be used to classify vertical wind speed profiles observed above a sloping forest at nighttime, where drainage flow often occurs? This paper examines the use of the bulk Richardson number to classify wind speed profiles observed above a sloping forest at nighttime. Wind speed profiles above a sloping forest were classified by the bulk Richardson number Ri _B . Use of Ri _B distinguished between drainage flow, shear flow, and transitional flow from drainage flow to shear flow. These results suggest that Ri _B is useful to interpret nighttime CO₂ and energy fluxes above a sloping forest. Through clear observational evidence, we also show that the reference height should be high enough to avoid drainage-flow effects when calculating Ri _B .     

Dew and rain water collection in the Dalmatian Coast, Croatia

Passive dew harvesting and rainwater collection requires a very small financial investment but can exploit a free, clean (outside urban/industrial zones) and inexhaustible source of water. This study investigates the relative contributions of dew and rain water in the Mediterranean Dalmatian coast and islands of Croatia, with emphasis on the dry summer season. In addition, we evaluate the utility of transforming abandoned roof rain collectors (“impluviums”) to collect dew water too. Two sites were chosen, an exposed open site on the coast favourable to dew formation (Zadar) and a less favourable site in a cirque of mountains in Komiža (Vis Island). Between July 1, 2003 and October 31, 2006, dew was collected two or three times per day on a 1 m² inclined (30°) test dew condenser, together with standard meteorological data (air temperature and relative humidity, cloud cover, windspeed and direction). Maximum yields were 0.41 mm in Zadar and 0.6 mm in Komiža. The mean yearly cumulative dew yields were found to be 20 mm (Zadar) and 9.3 mm (Komiža). Because of its physical setting, Komiža represents a poor location for dew collection. However, during the dry season (May to October), monthly cumulative dew water yield can represent up to 38% of water collected by rainfall. In both July 2003 and 2006, dew water represented about 120% of the monthly cumulative rain water. Refurbishing the abandoned impluviums to permit dew collection could then provide useful supplementary water, especially during the dry season. As an example, the 1300 m² impluvium at Podšpilje near Komiža could provide, in addition to rain water, 14,000 L dew water per year.     

典型拉尼娜事件与1988—1989年拉尼娜事件生命史演变差异性成因分析

利用海洋混合层海温热量收支诊断方法和两套海洋同化再分析资料,对比分析典型拉尼娜事件和1988—1989年特殊拉尼娜事件生命史演变成因。研究结果表明,典型拉尼娜事件在发展年冬季到达最强值后通常缓慢衰减,在次年秋季时再次增强形成第二次拉尼娜事件。而1988—1989年拉尼娜事件在发展年底时到达最强值后迅速衰减,并在次年秋季时依然维持衰减过程,最终回到气候平均态。诊断分析结果表明,风场强迫作用引起的纬向异常平流项变化是导致衰减年中两种类型拉尼娜事件海温变化倾向差异的主要原因。在典型拉尼娜事件衰减时期,西北太平洋上空以异常反气旋性环流为主,反气旋性环流南侧东风距平会激发海洋上翻Kelvin波向东传播,阻碍拉尼娜事件的衰减。而在1988—1989年特殊拉尼娜事件中,西北太平洋上空以异常气旋性环流为主。异常气旋性环流南侧西风距平将激发海洋下沉Kelvin波向东传播,引发海洋中自西向东的纬向异常暖平流帮助拉尼娜事件迅速衰减,最终回复到气候平均态。     

基于特征模理论的低剖面MIMO立方体天线

基于特征模理论,给出了一种适用于室内环境的16端口多输入多输出（MIMO）立方体天线设计.首先利用特征模理论在对一个矩形金属片进行模式分析的基础上,同时激励金属片的不同模式,设计了一款工作于5.150~5.875 GHz的高隔离度的4端口MIMO天线单元,并引入人工磁导体（AMC）表面代替原天线的地板,大大降低了天线的剖面.进一步地,围绕立方体环绕一周组成4×4端口的MIMO立方体天线,在较小的空间内实现了天线的多端口与多极化.仿真和测试结果表明：天线在5.150~5.875 GHz频段内端口反射系数S_ii<-10 dB,端口间隔离度|S_ij|>20 dB.     

Relaxed Eddy Accumulation Simulations of Aerosol Number Fluxes and Potential Proxy Scalars

Direct eddy-covariance measurements of aerosol number fluxes obtained during the 2007 CHATS field experiment in Dixon, California, USA are compared with relaxed eddy accumulation simulations using temperature and water vapour concentration as proxy scalars. After a brief discussion of the limited time response of the aerosol measurement, the applicability of temperature and water vapour concentration as proxy scalars for aerosol number concentration is investigated by evaluating scalar and spectral correlation coefficients as simple measures of scalar similarity. In addition, the proportionality factor b, which compensates for the use of a constant sampling flow in relaxed eddy accumulation, is derived from the time series of aerosol number, temperature and water vapour, and its variability is analyzed. The reduction of the b factor due to application of a deadband, i.e. the rejection of data when the vertical wind speed is close to zero, is evaluated for all three studied scalars, and compared with published functional relationships. In this study, using temperature or water vapour as proxy scalars for aerosol number shows no advantage over the use of a constant b factor. Thus, it is suggested to apply a deadband H _REA  = w′/σ _w  = 0.6 to 0.8 (where w′ is the vertical velocity fluctuation and σ _w is its standard deviation), to use a theoretical b factor based on a parameterization that includes a stability dependence, and to calculate the deadband effect according to a derived relation for aerosol relaxed eddy accumulation.     

A conceptual template for integrative human–environment research

Knowledge integration, the blending of concepts from two or more disciplines to create innovative new worldviews, is a key process in attempts to increase the sustainability of human activities on Earth. In this paper, we describe a ‘conceptual template’ that can be used to catalyse this process. The template comprises (a) a list of high-level concepts that capture the essential aspects of any significant human–environment problem, plus (b) broad lists of low-level basic concepts drawn from a range of disciplines. Our high-level concepts, which we call ‘conceptual clusters’, are labelled Dynamics & System, Organisation & Scale, Controlling Models, Management & Policy, Adaptation & Learning, and History. Many of the clustered, lower-level concepts are synonyms and thus provide possible connections between disciplines—for this reason we call them ‘nexus concepts’. We suggest that a conceptual template like that presented here can provide strong support to the initial phases of integrative research programs.     

Laboratory studies of the effects of interrupted, sloping topography on intermediate depth boundary currents in linearly stratified fluids

Laboratory experiments are described which provide insight into the interaction of intermediate depth boundary currents (IDBCs) with interrupted sloping topography. Specifically, they contribute to the debate over meddy formation on the Iberian continental slope. The experiments were performed in a rectilinear rotating tank filled initially with a linearly-stratified fluid. A false bottom sloped away from the side-wall along which the current flowed, and was interrupted by a gap of variable length. The effects of varying gap length and rotation rate on the boundary current were observed.In the first of two sets of experiments, the current flowed above the slope, along the vertical sidewall. In the second, the current flowed along the sloping bottom. In the former, current nose speed was consistent with geostrophic predictions, but decreased in the presence of a gap in the topography. Kelvin wave radiation is postulated as a reason for this. The IDBCs exhibited vortical lateral intrusions at values of the Burger number Bu=(N₀/Ω)² at which counterpart flat-bottom studies had been stable, implying that the sloping topography had a de-stabilising effect. Energy measurements and qualitative observations suggest the intrusions were due to mixed barotropic/baroclinic instabilities, the latter dominating at higher rotation rates.In the second configuration, four distinct flows were observed, distinguished by the deformation radius:gap width ratio R_D/G^*. For a range of values of R_D/G^*, attached eddies formed at the upstream end of the gap. They remained at this position, unlike those in similar studies of surface boundary currents (Klinger, 1993). Their persistence and ability to move downstream – salient factors for meddy – formation were greater for a finite gap size than a permanent change from sloping to flat bottom.