低温灾害长期预报初步探讨

我县位于乌苏里江西部,纬度较高,冬季严寒漫长,夏季湿热短促,无霜期短。因此,热量条件成为我地农作物生长发育最重要的条件。 我们对历年粮食平均亩产和气温、降水这两个气候因子的相互关系进行调查分析。结果发现:降水量的多寡及其分布对粮食产量的影响不显著;而气温的高低却与粮食单产显著相关。凡是低温年(指5—9月     

滇中水稻冷害的强低温长期预报

本文分析了昆明(能代表滇中地区)3-8月月积温及8月平均气温对水稻产量的影响,提出了水稻冷害的低温指标.本文得到:3-8月500毫巴西太平洋副高的强弱是影响昆明同期气温高低的重要因素,而该副高的强度有较好的持续性,故可据该副高1-2月的强度,预报滇中水稻冷害低温的有无.另外得出:西太平洋副高春夏季的强度,在上年11月已有反映,故可更早作出有无水稻冷害低温的估计.     

阿克苏“低温冷害”的长期预报因子的探讨

本文利用1951-1980年北半球500hPa和1964-1973年欧亚500hPa月平均高度及距平图,对阿克苏地区夏末秋初“低温冷害”的环流特点进行了分析,并在相关分析的基础上,给出预报该地区有无“冷害”的因子。     

用韵律编码法做低温冷害长期预报

分析八月高温与元月低温冷害的关系，结果表明：两者存在着很好的韵律性。通过逐日对八月气温＞35℃的高温日等气象要素进行编码，来预报元月低温时段，可得到改满意的预报结果，为越冬作物预防寒害提供了科学依据。亚拒津经场预报低温时段方法的制作1．且预报对象。按省局规定，日最低气温＜5℃为低温日。规定出现低温日y为五，否则y为0。1．2预报因干。共选择8个预报因子分别为：X；：8月B最高气温＞35℃，编码为1（起报日），否则为0；X。：起报日士5天内已＜996shP。，编为三，否则为0；Xs：起报日上5天内14时气区为月最低值编为1，否…     

北方四省协作研究低温冷害的长期预报

我国北方(黑龙江、吉林、辽宁、河北)四省是我国粮食的重要产区,而低温冷害是这个地区农业生产的主要自然灾害。建国以来,这个地区出现过八次低温早霜灾害,每次都造成粮食的大幅度减产。英明领袖华主席从第二次全     

春播期间的低温冷害预报

出现一次明显的天气过程,必有相应的同期环流形势为背景,而同期环流又与前期某一段时间环流之间存在着一定的关系。这种前后变化的相互关系,在单站要素上必然有一定程度的表现。依此思路,我们以温江县春播期间的低温冷害(以下简称冷害)为例,用1960—1976年的资料,分析产生冷害天气与同期环流的关系,以及同期环流与前期环流的相互关系。并在此基础上,利用9月平均温度与平均绝对湿度的距平和来预报春播期间的冷害天气。经4年试报和实际使用,效果较好。另外,还用与温江站相邻的5个站资料作试验,结论与温江站基本一致。现介绍如下。     

应用卫星遥感技术预报作物低温冷害

沈阳区域气象中心研究所的农气人员把卫星遥感技术应用到预报作物低温冷害中,取得了显著效果。该项研究成果于去年12月25日在沈阳通过了由省科委组织的技术鉴定。专家们认为,该项研究是高科技应用于辽宁省农业气象工作的一项新成果;以遥感技术作为获取低温冷害预报信息的手     

云南烤烟低温冷害风险区划

用云南93个烤烟种植县气象站1961—2010年4—9月逐日平均气温、逐日最低气温,逐月平均气温,平均最低气温资料结合各类型烤烟低温冷害指标,基于概率和强度结合权重指数,计算了各烤烟种植县的春季、夏季、秋初和全生育期综合低温冷害风险指数。使用低温冷害风险指数与海拔、纬度因子建立的空间推算回归模型,在ArcGIS 9.3平台下实现了低温冷害风险指数的空间精细化推算、订正及区划,进一步将其分类为5个风险等级,且对区划结果进行了分析。区划结果可为烤烟生产相关单位提供低温冷害防御的决策依据。     

基于东北玉米区域动力模型的低温冷害预报应用研究

在田间试验资料基础上,采用改进的发育模型和分区作物参数,结合前人有关研究成果建立了东北玉米区域动力模型,并利用模型模拟了12站40年 (1961~2000年) 玉米生长发育过程。确定抽雄期延迟天数为低温冷害指标,分析了历史低温冷害年及减产情况。模拟了典型冷害年和40年气候平均的0.25°×0.25°网格点玉米生长发育过程, 探讨了与区域气候模式结合进行低温冷害预报的方法。主要结论有：①玉米发育模型能够较好地模拟玉米发育期和发育期对低温冷害的响应,以抽雄期延迟天数为冷害指标评估的历史冷害发生状况基本符合历史实况。②模型有一定的模拟玉米生长量对低温冷害响应的能力,但还需要更多的试验数据校正品种参数,完善模型。③利用GIS技术,结合区域化的作物参数运行区域作物模型,是作物模型区域化应用的一种解决方案。④东北玉米区域动力模型解释性好,根据确定的害指标,以区域气候模式输出结果驱动玉米模型可以模拟和预测低温冷害,是农业气象灾害预测预报的一个有益的尝试。     

云南地区水稻低温冷害指标研究

利用2013年4—10月云南省昆明市东川地区4个不同海拔高度试验点水稻盆栽和跨海拔搬运试验资料,分析了海拔高度变化对水稻生长和产量的影响及光合作用特征,确定粳稻和籼稻生长最大差异的临界海拔高度,结合同步气象观测数据确定云南地区粳稻和籼稻拔节期、开花结实期及乳熟期的低温冷害指标.结果表明:由海拔高度变化造成温度的变化对云南地区粳稻和籼稻生长指标及光合作用特征均具有较大影响,粳稻受影响更显著;籼稻生长最大差异临界海拔高度为1500—1800 m,粳稻生长最大差异临界海拔高度为1800—2100 m;在云南地区水稻拔节期,籼稻低温冷害成灾指标为19.6℃,粳稻低温冷害成灾指标为17.2℃;在水稻开花结实期,籼稻低温冷害成灾指标为20.5℃,粳稻低温冷害成灾指标为18.1℃;在水稻乳熟期,籼稻低温冷害成灾指标为19.1℃,粳稻低温冷害成灾指标为16.7℃.     

A numerical study on forecasting the Henan extraordinarily heavy rainfall event in August 1975

This study is essentially an experiment on the control experiment in the August 1975 catastrophe which was the heaviest rainfall in mainland China with a maximum 24-h rainfall of 1060.3 mm, and it significantly demonstrates that the limited area model can still skillfully give reasonable results even only the conventional data are available. For such a heavy rainfall event, a grid length of 90 km is too large while 45 km seems acceptable. Under these two grid sizes, the cumulus parameterization scheme is evidently superior to the explicit scheme since it restricts instabili-ties such as CISK to limited extent, The high resolution scheme for the boundary treatment does not improve fore-casts significantly.The experiments also revealed some interesting phenomena such as the forecast rainfall being too small while af-fecting synoptic system so deep as compared with observations. Another example is the severe deformation of synoptic systems both in initial conditions and forecast fields in the presence of complicated topography. Besides, the fixed boundary condition utilized in the experiments along with current domain coverage set some limitations to the model performances.     

寒冷地区的科学界定及黑龙江省寒区划分

利用8项气候指标对黑龙江省寒区进行合理划分，得出5个寒区气候区，为了研究寒区的开发，促进寒区经济发展提供科学依据。     

区域雷灾易损性及其区划的实证分析

分析了区域自然环境、经济状况和雷电灾害情况,根据江西省雷电灾害资料和年平均雷暴日统计资料,选取雷击密度、雷电灾害频数、经济易损指标、生命易损指标作为雷灾易损性评价指标。对江西省各设区市的雷灾易损性进行了综合评估,初步形成了江西省雷灾易损度区划。提出了区域雷灾易损性分析和区划的模式,为区域防御和减低雷电损失的规划提供了科学依据。     

西太平洋台风路径业务数值预告模式及其初步使用结果

本文介绍一个西太平洋台风路径业务数值预告模式及其初步使用结果。该模式利用逆平滑算子提高了计算精度,应用最小二乘方原理引进初始时刻后六小时台风位置,从而改进了预告结果。69次试验性预报以及1977—1979年台风季节的48次业务预告的结果表明,该模式对西太平洋台风路径具有一定的预告能力。本文还指出了该模式存在的缺点与进一步改进的途径。     

多因子两值预报效能的初步探讨

到目前为止,对多因子两值预报,已有不少方法,如编码法、REEP法等。但诸方法并没有涉及两值预报的内在规律。本文从概率论角度对它进行了研究,提出了预报效能的概率估计法。 针对简单投票法,我们导出了数学表达式,用它们探讨了多因子预报比单因子预报优越的条件。发现多因子预报效能取决于1)因子数;2)各因子的历史拟合率;3)各因子历史拟合率之间的差异程度;4)预报原则等四方面因素。还发现历史拟合率小于0.5的因子是超负贡献的。     

高分辨率区域模式降水预报在云南的检验

为了解高分辨率区域数值模式降水预报在云南的预报效果和误差特点,针对华南中尺度模式、华东区域数值预报业务模式和中央气象台GRAPES-Meso模式对2017年9月—2018年12月云南降水预报进行检验分析。结果表明:华东模式降水预报效果整体最好,其降水的振幅接近实况,晴雨准确率也是最高,而华南和GRAPES模式空报率和漏报率普遍偏高。三种模式对滇东北、滇中西部、滇西北北部≥0.1 mm降水预报评分普遍较低,对滇南、滇西南、滇西边缘地区的评分普遍较高。在滇东北北部、滇中西部、及滇西北北部地区三种模式对≥10 mm降水TS评分普遍较低。对于≥25 mm降水,华东模式和华南模式在滇中、滇西地区的TS评分高于GRAPES模式。对于≥50 mm降水,华东模式和华南模式在滇东南、滇西南、滇西边缘及金沙江河谷沿线TS评分高于GRAPES模式。对于云南强降水天气过程,≥0.1 mm降水华南模式预报效果较好,但10 mm和25 mm以上量级降水华东模式的预报效果较好,≥50.0 mm则是GRAPES模式更具参考价值。     

云南省森林火险气象等级区划研究

以云南省为研究区,采用防火期内插值到每个格点的月平均降水量、月平均气温、月平均风速、月平均蒸发量、月平均相对湿度5个气象因子,以及栅格化的云南省树种和土地利用分布作为火险区划因子,通过将其标准化并赋予各因子不同的权重,利用ARCGIS的分析计算功能,对云南省防火期内进行森林火险气象等级划分,并以历史林火统计结果作为验证。从区划结果来看,12月至次年5月森林火险气象等级的发展趋势符合云南的实际情况。通过对照历史林火统计结果,该结果能反映云南省大部地区在防火期不同月份的森林火险气象等级分布规律     

A numerical study on the winter monsoon and cold surge over East Asia

By using the improved regional climate model （RegCM_NCC）, a numerical study has been undertaken for the East Asia region over a period of 5 years （1998-2002） in an effort to evaluate the model＇s ability to reproduce the winter monsoon conditions that were observed. The results showed that the model can successfully simulate the basic characteristics of the winter monsoon circulations, including the location and intensity of the cold-surface, high-pressure system, as well as the wind patterns and the intensity of the winter monsoon. The simulated occurrence frequency and regions of the cold surge were consistent with the observations. The simulated rainfall distribution over China was consistent with the observations collected in South China. The features of the simulated moisture transport were also in good agreement with the observations that were derived from the NCEP reanalysis data, indicating that moisture transport coming from the Bay of Bengal trough plays a crucial role in supplying moisture needed for precipitation in South China. In addition, the moisture transport coming from the near-equatorial west-Pacific was also important. These two branches of moisture transport converged in South China, as a prerequisite for occurrence of the precipitation that was observed there. Heat budgets have shown that the development of a heat sink over the East Asian continent was remarkable and its thermal contrast relative to the neighboring seas was the important forcing factor for the winter monsoon activity. The simulation also indicated that the significant differences in circulation patterns and rainfalls during the winters of 1997/98 and 1998/99 were affected by cold and warm ENSO events, respectively. The above analysis demonstrated the model＇s ability to simulate the East Asian winter monsoon.     

A numerical case study of the passage of a cold surge across Taiwan

Summary A numerical study of a cold surge that occurred from 19–23 December 2001 was conducted to better understand the cold surge characteristics over the Taiwan area. The National Centers for Environmental Prediction (NCEP) nested Mesoscale Spectral Model (MSM) was used for this study. Simulation results demonstrated that the nested NCEP MSM captured salient features of the selected cold surge case. We demonstrated that the local minimum center of the time change of virtual potential temperature (dVPT) can serve as the location of severe weather of the cold surge for all Taiwan regions. Furthermore, thermodynamic equation analyses revealed that the leading edge of the cold surge was maintained primarily by meridian thermal advection, while diabatic heating, vertical and zonal thermal advections were less important. The cold surge flows were blocked and lifted by the Central Mountain Range (CMR) on its windward side, which increased the cold surge’s vertical extent upward and increased northwestward tilting in the vertical structure. The flow eventually ascended, switched direction toward Taiwan, and descended over its northwestern and eastern coasts. The physical and circulatory characteristics of the cold surge differed noticeably on both sides of Taiwan. The cold surge’s leading edge over the Taiwan Strait was northeast-southwest oriented and had evident wind shear; on the east side of the island, it was stronger in intensity and faster-moving than its counterpart on the west side. Sensitivity experiments revealed that the CMR’s trapping of cold surge flows on its windward side affected cold surge leading edge characteristics in the following five ways: (1) weakening its intensity over the ocean but enhancing it inland, (2) decreasing its southward speed, especially over the western low plains region, but increasing its movement on the east coast, (3) increasing its vertical altitude and narrowing the horizontal extent of its vertical tilting, (4) altering its upper vertical circulatory structure, and (5) trapping a V-shape density current and enhancing its intensity in connection with the land-sea contrast.