共查询到20条相似文献，搜索用时 15 毫秒
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为了提高雾与能见度的预报水平,对业务上常用的两种能见度诊断方案,即Stoelinga and Warner（SW）方案与Forecast Systems Laboratory（FSL）方案的改进进行预报试验,SW方案基于Gultepe方案考虑了液态水粒子数浓度对能见度的影响,FSL改进方案中利用了递减平均法对公式中用到的温度与露点温度进行订正,并用其重新计算公式中的相对湿度。基于山东省气象科学研究所逐时更新循环（hourly update cycle,HUC）业务模式输出结果,从2015—2016年选取10次雾天气过程,并详细分析了2015年11月13—14日这次雾天气过程的预报结果,比较了改进前后各方案对雾与能见度的预报效果,结果显示：在模式预报的雨水含量占总液态含水量比例较大的预报时效,改进后的SW方案对雾与能见度预报效果优于原始方案,在模式预报液态含水量接近0的预报时效,改进前后的SW方案对雾与能见度的预报效果相当;利用订正的温度与露点温度重新计算相对湿度,其平均绝对误差（mean absolute error,MAE）降低明显的预报时段,改进后的FSL方案对雾与能见度的预报效果大大提升。将两种改进后的方案相融合并进行预报试验,结果显示,综合对能见度与雾的预报效果,Combined Visibility（CVIS）方案要优于其他两种改进方案。 相似文献
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利用2009年8月—2010年7月的平行观测资料,对新型自动气象站中百叶箱和通风辐射罩气温观测系统气温日最值对比差的分布、粗差率、一致率以及平均值等进行统计,对日最值的出现时间进行对比,对日最值对比差与环境风速的关系进行分析,建立并验证了百叶箱气温日最值的订正方法。结果表明:百叶箱和通风辐射罩气温日最值对比差的分布均呈右偏态,且偏斜程度较大,不服从正态分布;日最高气温与最低气温的一致率分别为90.0%和81.5%,两者存在较大差异,但其粗差率基本一致,均略高于3.0%;与通风辐射罩气温观测系统相比,百叶箱的日最值数据总体偏高0.2℃左右,同时其出现时间也存在不同程度的滞后;气温日最值的差异会随着环境风速的增强而减小,特别是当风速大于4.5 m·s-1时,其差异可缩小到0.1℃以内;以环境风速为主要参数的气温订正方法将最高气温的差异缩小到0.03℃,一致率提高到95.2%,将最低气温的差异缩小到0.01℃,一致率提高到94.1%。 相似文献
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In weather sciences, the two specific terms “storm” and “cyclone” frequently appear in literature and usually refer to the violent nature of a number of weather systems characterized by central low pressure, strong winds, large precipitation amounts in the form of rain, freezing rain, or snow, as well as thunder and lightning. But what is the connection between these two specific terms? In this paper, the historic evolutions of the terms “storm” and “cyclone” are reviewed from the perspective of... 相似文献
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B. Ashraf R. Yazdani M. Mousavi-Baygi M. Bannayan 《Theoretical and Applied Climatology》2014,118(1-2):35-46
The aim of this research is to study the spatial and temporal variability of aridity in Iran, through analysis of temperature and precipitation trends during the 48-year period of 1961–2008. In this study, four different aridity criteria have been used to investigate the aridity situation. These aridity indexes included Lang’s index or rain factor, Budyko index or radiational index of dryness, UNEP aridity index, and Thornthwaite moisture index. The results of the analysis indicated that the highest and lowest mean temperatures occurred in July and January respectively in all locations. Among the study locations, Ahvaz with 37.1 °C and Kermanshah with 20.2 °C has the highest and lowest in July. For January, the highest was 12.4 °C for Ahvaz and the lowest was ?4.5 °C for Hamedan and Kermanshah together. The range of monthly mean temperature of study locations indicated that the maximum and minimum difference between day and night temperatures, almost in all study locations, occurred in September and January, respectively, and the highest and lowest fluctuation of temperature was observed in Kerman and Tehran. The temperature anomalies showed that the most significant increasing temperature occurred at the beginning of twenty-first century (2000–2008) in all locations. The long-term mean of monthly rainfall showed that, in most study locations, the maximum and minimum of mean precipitation occurred in winter and summer, respectively. Rasht with 1,355 mm had the highest and Yazd with 55 mm had the lowest of total precipitation compared with other locations. According to precipitation anomalies, all locations experienced dry and wet periods, but generally dry periods occurred more often especially in the beginning of twenty-first century. According to applied different aridity indexes, all the study locations often experienced semi-arid to arid climate, severe water deficit to desert climate, arid to hyperarid climate, and semi-arid climate during the study period. 相似文献
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气象与环境学报》编辑部与北京玛格泰克科技发展有限公司开展技术合作,于2008年初开通了由该公司开发研制的“稿件远程采编处理系统”和“网站系统”。系统主要包括作者在线投稿系统、作者在线查稿系统、在线审稿系统、编委在线审稿系统、主编在线审稿系统和远程编辑系统。实现了作者、审者、编者在线稿件收稿、审稿、退修、发稿通知的全过程监控与管理。网站包括期刊介绍、编委会、投稿须知、期刊订阅、广告合作和编辑部公告等信息。系统运行以来,加快了稿件处理效率,缩短了论文刊登周期,提高了工作效率,扩大了期刊传播影响力,方便了广大作者和读者,促进了编辑业务现代化建设的进展。通过对《气象与环境学报》稿件远程采编处理系统的建设和应用的叙述,概述了网站与系统的功能和设置,归纳了应用效果与体会,讨论了系统和网站的特点与存在的问题。 相似文献
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Theoretical and Applied Climatology - An attempt has been made, in this paper, to understand the characteristics and trends of temperatures of Kolkata, India, by using the temperature extremes, as... 相似文献
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冬小麦风雹灾害的等级划分与灾情评估 总被引：12，自引：0，他引：12
以冬小麦的风雹灾害为研究对象,从１９８１～１９９０年３３个冰雹个例中选取与冬小麦生长有关的１７个个例,以冰雹直径、降雹时间、降雹时阵风为因子,对冬小麦风雹灾害进行等级划分及灾情评估。应用证明,这些研究对提高农业灾害的管理水平具有重要意义。 相似文献
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利用ＩＡＰＧＣＭ２５年的积分结果,系统分析了模式的１、７月月平均气候,并与观测资料、ＯＳＵＧＣＭ和其它大气环流模式的模拟结果作了比较,所比较的变量包括大气基本变量即海平面气压、表面气温和降水以及与流场、加热场和水汽场有关的诸多变量。结果表明,模式成功地模拟出各种大气变量的分布特征,大多数变量的模拟结果要优于ＯＳＵＧＣＭ,从而证实模式对１、７月月平均气候有较好的模拟能力,特别是由于ＩＡＰＧＣＭ与ＯＳＵＧＣＭ两模式物理过程十分相似,这一结果还进一步证实了ＩＡＰＧＣＭ动力框架和计算方案的优良性能。模拟的主要误差包括南极槽偏浅、冰雪区表面气温偏高以及主要降雨区雨量偏大等,同时还分析了模拟误差的可能原因,提出了改进模式的一些设想。此外,计算并比较分析了模式中动量、感热和水汽的经向输送。 相似文献
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Measurements made as part of studies of the evolution of the planetary boundary layer (the Sangamon experiments of 1975 and 1976) are used to compare the surface eddy fluxes of heat and momentum over adjacent fields of soybeans and maize. Although the maize canopy was much taller and rougher than that of the soybeans, daytime eddy fluxes of momentum over the maize exceeded those over the soybeans by only about 35%, in good agreement with predictions based on PBL similarity theory. Heat flux was about 10% greater over the maize, probably as a consequence of greater evaporation over the soybeans. Infrared surface temperatures generally differed by less than 0.4 °C and net radiation by less than 10%. For the soybean canopy, the momentum displacement height was found to be located at approximately 90% of the crop height, and the roughness length was about 5%. The roughness length for sensible heat transfer was found to be 2–3% of the soybean canopy height. For the maize canopy, the momentum displacement height was about 60% of the crop height, and the roughness length about 7%.Work supported under the auspices of the U.S. Department of Energy. 相似文献
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3种光温指标在模拟设施黄瓜生长发育中的应用与比较 总被引：2，自引：0，他引：2
2011年9～12月间,以黄瓜“津优1号”（ Cucumis sativus linn. cv. Jingyoul ） 为试材,在南京信息工程大学试验温室进行分批栽培试验,测定温室气象要素和作物数据,分别用活动积温（AAT,Ac-tive accumulated temperature ）、有效积温（ EAT, Effective accumulated temperature） 和辐热积（TEP,Thermal effectiveness and photosynthesis active radiation）3种光温指标模拟温室黄瓜植株叶面积、株高和生育期,并利用独立试验数据对各个模型进行验证。结果表明：用辐热积指标分别模拟黄瓜各生育期（出苗期、开花期、坐果期、果实膨大期、成熟期）距播种日期的天数,其相对标准误差（RMSE）分别为0d,3d,4d,5d,4d,小于活动积温法（1d,6d,8d,11d,11d）和有效积温法（0d,4d,3d,8d,10d）。利用辐热积指标模拟叶面积和株高的相对标准误差（RMSE）分别为43．0cm^2和4．3cm,决定系数（R^2）分别为0．98和0．98,而用活动积温和有效积温指标模拟黄瓜单株叶面积的相对标准误差（RMSE）分别为61．3cm^2和54．6cm^2,模拟株高的相对标准误差（RMSE）分别为9．8cm和7．5cm。比较结果显示利用辐热积指标模拟温室黄瓜生育期、株高和叶面积的精度明显高于活动积温和有效积温,该研究为温室黄瓜生长指标和各生育期的预测以及环境调控提供参考。 相似文献
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内蒙古专业气象预警与气象预警系统的建立 总被引：2，自引：2，他引：0
通过分析内蒙古主要气象灾害的种类和特征,找出目前气象预警存在的不足之处,研究适合内蒙古地区的专业气象预警机制,并建立气象预警系统,使专业气象预警产品更好地为公众及各行业服务。 相似文献
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文章主要讨论了传统媒体和新媒体对气象节目的需求、发展以及创新。认为:气象信息的传播实现新旧媒体的互补是电视天气预报今后改革和创新的必然趋势;在巩固传统媒体的基础上,充分把握新媒体的特点,寻找和开发适合新媒体的天气预报节目,拓宽气象信息的传播渠道,增强气象服务的能力。 相似文献
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为保障饮用水源地闹德海水库的水质安全,通过选取不同氮磷允许负荷量的测算模式进行综合分析。结果表明:闹德海水库实际负荷量总氮为139.98 t/a、总磷为28.28 t/a,目前已处于中—富营养化状态;水库若要达到贫—中营养化状态,应削减总氮129.96 t/a,总磷27.27 t/a。为此,从发展农业节水、综合防治化肥、农药、畜禽养殖业污染及治理水土流失等方面提出了科学的污染防治思路及削减对策。 相似文献
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The daily outgoing longwave radiation (OLR) field in boreal summer shows significant power spectrum peaks on quasi-biweekly (10–20-day) and intraseasonal (20-80-day) timescales over the Indo-western Pacific warm pool, especially over the South China Sea and Bay of Bengal. The quasi-biweekly oscillation (QBWO) originates from off-equatorial western North Pacific, and is characterized by a northwest-southeast oriented wave train pattern, propagating northwestward. The intraseasonal oscillation (ISO), on the other hand, originates from the equatorial Indian Ocean and propagates eastward and northward. Why the equatorial mode possesses a 20–80-day periodicity while the off-equatorial mode favors a 10–20-day periodicity is investigated through idealized numerical experiments with a 2.5-layer atmospheric model. In the off-equatorial region, the model simulates, under a realistic three-dimensional summer mean flow, the most unstable mode that has a wave train pattern with a typical zonal wavelength of 6000 km and a period of 10–20 days, propagating northwestward. This is in contrast to the equatorial region, where a Madden-Julian oscillation (MJO) like mode with a planetary (wavenumber-1) zonal scale and a period ranging from 20 to 80 days is simulated. Sensitivity experiments with different initial conditions indicate that the QBWO is an intrinsic mode of the atmosphere in boreal summer in the off-equatorial Indo-western Pacific region under the summer mean state, while the MJO is the most unstable mode in the equatorial region. 相似文献
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P. G. Duynkerke P. J. Jonker A. Chlond M. C. Van Zanten J. Cuxart P. Clark E. Sanchez G. Martin G. Lenderink J. Teixeira 《Boundary-Layer Meteorology》1999,92(3):453-487
As part of the EUropean Cloud REsolving Modelling (EUCREM) model intercomparison project we compared the properties and development of stratocumulus as revealed by actual observations and as derived from two types of models, namely three-dimensional Large Eddy Simulations (LES) and one-dimensional Single Column Models (SCMs). The turbulence, microphysical and radiation properties were obtained from observations made in solid stratocumulus during the third flight of the first 'Lagrangian' experiment of the Atlantic Stratocumulus Transition Experiment (ASTEX). The goal of the intercomparison was to study the turbulence and microphysical properties of a stratocumulus layer with specified initial and boundary conditions.The LES models predict an entrainment velocity which is significantly larger than estimated from observations. Because the observed value contains a large experimental uncertainty no definitive conclusions can be drawn from this. The LES modelled buoyancy flux agrees rather well with the observed values, which indicates that the intensity of the convection is modelled correctly. From LES it was concluded that the inclusion of drizzle had a small influence (about 10%) on the buoyancy flux. All SCMs predict a solid stratocumulus layer with the correct liquid water profile. However, the buoyancy flux profile is poorly represented in these models. From the comparison with observations it is clear that there is considerable uncertainty in the parametrization of drizzle in both SCM and LES. 相似文献
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João A. Hackerott Mostafa Bakhoday Paskyabi Joachim Reuder Amauri P. de Oliveira Stephan T. Kral Edson P. Marques Filho Michel dos Santos Mesquita Ricardo de Camargo 《Boundary-Layer Meteorology》2017,165(2):211-231
We discuss scalar similarities and dissimilarities based on analysis of the dissipation terms in the variance budget equations, considering the turbulent kinetic energy and the variances of temperature, specific humidity and specific CO\(_2\) content. For this purpose, 124 high-frequency sampled segments are selected from the Boundary Layer Late Afternoon and Sunset Turbulence experiment. The consequences of dissipation similarity in the variance transport are also discussed and quantified. The results show that, for the convective atmospheric surface layer, the non-dimensional dissipation terms can be expressed in the framework of Monin–Obukhov similarity theory and are independent of whether the variable is temperature or moisture. The scalar similarity in the dissipation term implies that the characteristic scales of the atmospheric surface layer can be estimated from the respective rate of variance dissipation, the characteristic scale of temperature, and the dissipation rate of temperature variance. 相似文献
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Mingqun Huo Qian Sun Yuhua Bai Peng Xie Zhaorong Liu Jinlong Li Xuesong Wang Sihua Lu 《Journal of Atmospheric Chemistry》2010,67(1):29-43
Rainwater samples were collected at four sites, including Beijing and Mazhuang Town in the north of China, Shenzhen and Mangdang
Mountain in the south of China. Character of atmospheric particles and gases were also measured at Mazhuang Town and Mangdang
Mountain. Both of Beijing and Shenzhen are urban sites; Mazhuang Town and Mangdang Mountain are rural and remote sites respectively.
The atmospheric pollution at rural plain site in the north of China was more serious than that at remote mountain site in
the south of China. At Beijing, Mazhuang Town, Shenzhen and Mangdang Mountain the average pH values in rainwater were 6.02,
5.97, 4.72 and 4.81, respectively and the concentrations of total ions in rainwater were 1454, 1125, 187 and 191 μeq/l, respectively.
While the acidity of the rain was higher in the south than that in the north, the rainwater in the north of China was more
severely polluted than that in the south. The major acidic ion in the rainwater is SO42-, and NH4+ is the most important neutralizing ion in rainwater at the four sites, followed by Ca2+. The amounts of organic acid in precipitation were compared with other sites in the world. The ratios of organic acid to
total free acid in rainwater at Mangdang Mountain was 13.8% and the influence of organic acid on acidity of rainwater at mountain
site in the south of China is more important. The variation of atmospheric particles, gases and components in rainwater and
cloud-fog water during special rain and cloud-fog events was discussed. The importance of washout process varied with atmospheric
species. The impacts of rainfall, rain duration time and wind speed on wash-out process were estimated by regression analysis. 相似文献