共查询到20条相似文献，搜索用时 187 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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简要叙述了国内外棉花生长发育模拟模型，棉花专家系统和棉花生产管理决策系统的发展，重点介绍了美国的GOSSYM模拟模型和我国的COTGROW模拟模型等最成功的研究成果。 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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介绍了卫星数字电话网络系统（ＴＥＳ）的功能、指示器及其ＬＥＤ代码解析。介绍了程控交换机（ＨＪＤ－８０型）的功能,故障的处理及系统的诊断测试内容和维护方法。 相似文献
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利用安康及石泉水库2000—2011年逐日入库流量及对应时段安康及石泉流域观测站逐日降水资料,分析了安康及石泉水库入库流量的变化特征及其与流域面雨量的关系。结果发现,安康及石泉入库流量主要集中在7到10月,极端入库流量在7—9月的出现频率最大;入库流量变化与其流域面雨量关系密切,其中6—10月,逐日入库流量与面雨量呈显著正相关;随着面雨量的增长,入库流量呈阶段性增长趋势,安康水库入库流量分别在流域面雨量达到20 mm和40 mm时显著增加,石泉水库入库流量则分别在流域面雨量达到15 mm和30 mm时大幅增加;建立了引入降水累积效应的汛期安康及石泉水库入库流量预测模型,经检验表明模型能较好地模拟入库流量的实际变化,对电力部门汛期水量调度有参考价值。 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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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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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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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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正确安装、维护和使用暗筒式日照计 总被引：3，自引：0，他引：3
暗筒式日照计是气象台站测定地面日照时数的仪器。按照《地面气象观测规范》要求日照计应安置在开阔的、终年从日出到日没都能受到太阳光照射的地方,通常安置在观测场内或平台上。我们在业务检查工作中经常发现台站未能正确安装暗筒式日照计。那么台站如何正确安装日照计?日照计安装不正确其感光迹线表现在哪些方面?如何判断日照纸涂药的优劣?下面具体予以介绍。1正确安装暗筒式日照计的三个要点a)仪器安装水平:首先日照计支柱底座要调准水平,同时日照计也要调准水平。b)筒口对准正北:台站应用北极星法、日中线法等方法精确测定本站子午线,… 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