Classified Early Warning and Forecast of Severe Convective Weather Based on LightGBM Algorithm

Severe convective weather can lead to a variety of disasters, but they are still difficult to be pre-warned and forecasted in the meteorological operation. This study generates a model based on the light gradient boosting machine (LightGBM) algorithm using C-band radar echo products and ground observations, to identify and classify three major types of severe convective weather (i.e., hail, short-term heavy rain (STHR), convective gust (CG)). The model evaluations show the LightGBM model performs well in the training set (2011-2017) and the testing set (2018) with the overall false identification ratio (FIR) of only 4.9% and 7.0%, respectively. Furthermore, the average probability of detection (POD), critical success index (CSI) and false alarm ratio (FAR) for the three types of severe convective weather in two sample sets are over 85%, 65% and lower than 30%, respectively. The LightGBM model and the storm cell identification and tracking (SCIT) product are then used to forecast the severe convective weather 15 - 60 minutes in advance. The average POD, CSI and FAR for the forecasts of the three types of severe convective weather are 57.4%, 54.7% and 38.4%, respectively, which are significantly higher than those of the manual work. Among the three types of severe convective weather, the STHR has the highest POD and CSI and the lowest FAR, while the skill scores for the hail and CG are similar. Therefore, the LightGBM model constructed in this paper is able to identify, classify and forecast the three major types of severe convective weather automatically with relatively high accuracy, and has a broad application prospect in the future automatic meteorological operation.

Early warning for geo-hazards based on the weather condition in China

According to national early warning practice for geo-hazards from 2003 to 2005,it is systematically concluded that the basic characteristics of geo-hazards,early warning method and forecast result based on the geological maps of China in a scale 1∶6 000 000.With the contrast of different characters between sustained rainfall and typhoon rainfall inducing geo-hazards,the disaster reduction result and some problems are preliminarily analyzed.Some basic recognition is that early warning to geo-hazards is feasible,national scale forecast is only to call attention,but can't immediately be used to disaster reduction decision-making.And,the future direction is to build a united disaster reduction framework of early warning system including national,provincial and county levels based on weather factors in different scale of area.

Development and Application of Meteorological Disaster Monitoring and Early Warning Platform for Characteristic Agriculture in Huzhou City Based on GIS

Based on the needs of characteristic agricultural production for meteorological services in Huzhou City,we use C# programming language to develop the meteorological disaster monitoring and early warning platform for characteristic agriculture in Huzhou City. This platform integrates the functions of meteorological and agricultural information monitoring,disaster identification and early warning,fine weather forecast product display,and data query and management,which effectively enhances the capacity of meteorological disaster monitoring and early warning for characteristic agriculture in Huzhou City,and provides strong technical support for the meteorological and agricultural departments in the agricultural meteorological services.

输电线路气象风险精细化建模及气象灾害的在线预警防御策略

气象因素在输电线路稳定运行中起着重要作用,在评估风险时应予以考虑。为此,提出一种输电线路气象风险预警及防护方法。该方法考虑时空发电预测、设备健康和可靠性评估以及概率负荷预测等方面对气象风险进行精细化建模,并基于气象危害、电网脆弱性和灾后恢复成本提出一种新的风险度量标准。此外,针对负荷中断恢复以及缓解用电拥堵,提出一种气象灾害的在线预警防御策略。最后,在案例中对所提出的方法和策略进行测试分析,其结果可以验证方法和策略的有效性。

乌苏市重污染天气分型及预警预报方法研究

针对乌苏市重污染天气展开深入研究,通过综合分析大量气象和空气质量监测数据,揭示重污染天气的特征和形成机制。研究发现,乌苏市重污染天气分为2种类型,即冬季工业排放型和静稳天气逆温型。为了加强对重污染天气的科学预测和有效防控,提出一套基于数据挖掘和时间序列分析的预警预报方法。在实施预警预报的同时,要加强宣传,建立公众参与平台,通过社交媒体向居民传递实时的重污染天气信息,以便采取防护措施。

毫米波云雷达在高影响天气中的预警应用

为提高城市高影响天气的精细化预报预警水平,利用雄安新区2020年1月—2023年12月容城气象站Ka波段毫米波云雷达反射率因子、径向速度等7种产品及地面气象资料和天气学、雷达回波图像形态分析等方法对雄安新区暴雨、大风、雾、霾及沙尘等高影响天气进行分析。结果表明:1)云雷达对含降水的高影响天气云体探测结构清晰、垂直分布特征直观。当春、夏、秋季回波强度≥21 d BZ(冬季≥15 d BZ)、伸展高度≥5 km(冬季≥2 km)的云体出现,且云体最低高度达150 m时,可看作地面降水将出现的特征指标,时间提前量平均达20 min左右,当回波强度减弱、云底高度抬升,降水趋于结束;各级降水中,暴雨的强回波伸展高度、云水含量等最大。2)当回波顶伸展高度达8 km之上而后快速下落至云顶高度≤2 km时,地面易出现8级以上大风,降水伴大风的回波特点为强回波区中形成明显的U或V型缺口,缺口区最大径向速度达12.5 m·s^(-1)左右。3)云雷达反演滴谱数据产品可较好反映各级降水的粒子分布特征;垂直积分液态水含量(Vertically Integrated Liquid Water,VIL)对降水伴大风有预警指示意义,提前量0~30 min或以上。4)非含降水的高影响天气(雾、霾、沙尘等),云雷达回波强度等整体偏弱,各天气现象之间界限不清晰,但与降水天气发生转换时云雷达能快速、清晰地探测出降水云体,有利于提升降水的精细预报预警能力。

上榆泉煤矿综放工作面回风隅角低氧原因分析及预测

针对上榆泉煤矿综放工作面回风隅角附近低氧问题开展分析研究,根据实地调研,对导致低氧现象发生的气压、温度、湿度主要因素进行实时监测并建立数据库,进而分析地表温度、大气压对工作面低氧现象影响途径和程度,提出对综放工作面低氧现象超前预测预警的理念,为综放工作面现场安全生产提供必要信息,也为采取低氧治理措施提供基础依据。

Assessment of Socio-Economic Impacts of the December 2011 Flood Event in Dar es Salaam, Tanzania

Floods are the most devastating hazards that have significant adverse impacts on people and their livelihoods. Their impacts can be reduced by investing on: 1) improving the forecasting skills of extreme and heavy rainfall events, 2) development of Impacts Based Flood Early Warning System (IBFEWS) and 3) effective communication of impacts from anticipated extreme or heavy rainfall event. The development of IBFEWS however, requires a complete understanding of factors that relates to the formation of extreme or heavy rainfall events and their associated socio-economic impacts. This information is crucial in the development of Impacts Based Flood Forecasting Models (IBFFMs). In this study, we assess the socio-economic impacts of the December 2011 flood event in Dar es Salaam as the preliminary stage in the development of IBFFMs for the City of Dar es Salaam. Data from household survey collected using systematic random sampling techniques and structured questionnaires are used. The survey was conducted to acquire respondent’s views on the causes of floods impacts, adaptive capacity to extreme or heavy rainfall events and adaptation options to minimize flood impact. It is found that the main causes of floods were river overflow due to heavy rainfall and blocked drainage system. Poor infrastructure such as drainage and sewage systems, and ocean surge were identified to be the causes of observed impacts of the December 2011 flood event in Dar es Salaam. Death cases analysis showed that 43 people were reported dead. The flood event damaged properties worth of 7.5 million Tanzania shillings. Furthermore, the Tanzania Government spent a total amount of 1.83 billion Tanzanian shillings to rescue and relocate vulnerable communities that lived-in low-lying areas of Jagwani to high ground areas of Mabwepande in Kinondoni district.

Analysis on Radar Characteristics of a Short-time Heavy Rainfall Event in Wuchuan County

Using minute rainfall data of automatic ground station and a variety of products from new generation Doppler weather radar in Wuchuan, the characteristics of a short-time heavy precipitation process on April 23, 2022 were analyzed. The results showed that the appearance of differential reflectivity(ZDR) column and big-value zone of high-elevation ZDR had better indication on short-term heavy rainfall process in Shichao station. Ice phase process played a very important role in particle growth. The storm tracking information product can predict the path of the storm 15 min in advance. The storm stayed and moved less or even turned back to more than two to three scanning volumes in one place, indicating the occurrence of short-term heavy rainfall. One-hour accumulated precipitation(OHP) had a good effect on the estimation of continuous precipitation in a large area where the hourly rainfall exceeded 50 mm for more than two stations. It had the ability to estimate short-term heavy precipitation in areas lacking automatic stations.

探析恶劣天气对靖宇县设施农业的影响及气象预报预警技术

近年来,靖宇县设施农业发展势头正猛,规模越来越大。但是在全球气候增暖的形势下,靖宇县寒潮、冰雹、暴雨洪涝、大风等恶劣天气越来越多,给靖宇县设施农业的发展也带来了极大的阻力。基于此,根据靖宇县气候实际,分析了靖宇县恶劣天气对设施农业的影响,并积极探索了气象预报预警技术,以供参考。

气象为现代农业生产服务工作思考

阐述了气象为现代农业生产服务在甘南藏族自治州的工作实践,在概述甘南州现代农业发展状况的基础上,具体描述了气象部门所提供的气象服务,并就气象服务工作中的不足提出了相关完善建议,以供参考。

高分辨率区域模式产品在内蒙古东南部地区的释用分析——以赤峰市东北部一次凌晨强对流过程为例

近年来,GRAPES-MESO区域数值模式产品不断升级更新,在基层业务工作实践中取得了良好的应用效果。以2021年汛期赤峰市东北部地区一次受东北冷涡激发,在凌晨时段生成发展的中尺度强降水天气过程为例,通过对比GRAPES-MESO产品与地面观测实况,分析高分辨率区域模式产品在内蒙古东南部地区的表现。总结高分辨率区域模式产品在基层业务工作中的释用分析方法,以期加强数值模式产品在基层的应用,提高基层预报预警、监测服务工作质量。

极端天气背景下黑龙江省森林防灭火工作的思考

综合分析近年来全球极端天气趋势、2021年黑龙江省极端天气成因以及极端天气对黑龙江省林火三要素火源、可燃物、氧气带来的不利影响,从预警预报、物候监测、应急预案、航空消防体系等角度针对性提出黑龙江省应对极端灾害天气的具体措施。

地质灾害气象预报预警方法探讨——以四川省地质灾害气象预报预警为例

通过研究确定区域地质灾害发生的地形地貌、地层岩性、地质构造等地质环境背景条件,寻找地质灾害发生与气象因素的耦合关系,建立汛期地质灾害气象预报预警模型,结合强降雨天气的预报,对地质环境背景条件与气象因素的叠加评价,对地质灾害的易发程度及分布范围进行预报预警。以四川省地质灾害气象预报预警工作为例,初步建立了地质灾害气象预报预警模型和信息的评价、会商、签发、发布、接收、处理及反馈程序。2003年汛期应用证明,区域性地质灾害的预报预警水平明显提高。

地质灾害气象预报预警方法研究

地质灾害的诱发因素包括自然因素和人为因素.人为因素主要与人类工程活动有关.在一定的地质地形条件下,自然诱发因素则主要是降雨.因此在确定的地质环境背景下,研究气象和地质灾害发生的耦合关系极其重要.本文通过总结前人关于地质灾害预报预警的研究,提出了一套完整的应用降雨对地质灾害进行预报预警的方法体系.

天气形势预测法在深圳市空气质量预报中的应用研究

基于深圳市2013年4月-2014年3月每日气象观测数据和空气质量监测数据,分析了深圳市不同空气污染程度下的天气规律及影响要素特征,并通过将天气系统分为13种类型,在寻求与建立不同天气类型情景下污染物（PM2.5、PM10、SO2、NO2、CO、O3与AQI指数）变化函数的基础上,构建了天气形势预测模型对深圳市未来1-3 d空气质量进行预测。结果表明：（1）整体而言,低压系统和辐合区有利于深圳市大气污染物的扩散,而高压系统和均压区不利于大气污染物的扩散。（2）当深圳市出现轻度以上污染时,陆地一般由高压系统所控制,且深圳以处于高压前部分主。（3）天气形势预测模型对深圳市AQI指数的24、48、72 h预报相对误差分别为22.0%、22.2%与21.9%,该模型具有一定的准确率和可靠性,对空气质量预测具有较好的应用价值,可为空气质量预报预警提供科学的参考依据。

V型缺口在C波段多普勒雷达中的应用研究

利用普洱CIND3830-CC天气雷达资料、地面观测资料进行统计分析,研究2004—2013年普洱C波段天气雷达中V型缺口的统计特征、V型缺口与地面降雹的对应关系,并对V型缺口在冰雹预警方面的应用及其对短时临近预报预警的影响进行探讨,结果表明：（1）V型缺口的最佳观测仰角为0.5°~2.4°,垂直高度上,V型缺口的高度出现在2.1~6.5 km。（2）将V型缺口分为2种类型,第一类为块状强回波单体径向后侧的V型缺口,第二类为片状或块状多单体回波径向后侧的V型缺口。（3）第一类V型缺口的组合反射率（CR）为50~66 dBz,普遍≥55 dBz,出现冰雹的几率为69%。（4）第二类V型缺口的CR为47~64 dBz,普遍为50~55 dBz,出现冰雹的几率为29%。（5）当出现V型缺口、H_（45 dBz）≥7.5 km、CR≥55 dBz时,可预报有冰雹出现,准确率达100%,V型缺口对冰雹预警的时间提前量为5~102 min。此外,得出了V型缺口内冰雹回波的识别方法。

能源预测预警理论与方法研究进展

能源作为一种稀缺性的战略资源是国民经济增长和社会进步的物质基础,但是随着化石能源耗竭及能源使用造成的环境问题日趋严重,能源安全问题逐渐成为关注的焦点,而能源预测预警也成为能源系统科学领域的新兴学科,其内容包含能源安全理论、基于模型的能源供需预测和基于安全评价指标体系的能源预警等方面内容。通过系统回顾能源安全的理论及其演变的历程,重点综述了自上而下、自下而上和混合建模3种建模思路的能源预测模型,探讨了三类模型的优点和局限性,并根据能源安全预警评价指标浓缩信息的程度,将现有预警评价体系划分单个型指标评价体系和聚合型指标评价体系两大类。通过对以上研究内容的总结分析,明确了当前能源预测预警研究各领域的研究进展,及其在理论和应用方面的优势与不足。在未来研究中,建议从供应链的角度出发,考虑能源系统内部各因素及与外部因素的相互作用,构建基于链式的预警体系,以有效弥补现有研究中的不足。

内蒙古牧区雪灾的预警

利用地面和遥感监测相结合的方法,运用雪灾监测评估等级国家标准,实现了雪灾的定量化评估;结合牧用天气预报指标阈值,建立了内蒙古牧区不同草地类型雪灾等级预警方法,制作了雪灾预警等级分布地图。实况检验和预报结论基本相符,说明本预报方法能够对雪灾的范围和影响程度进行预估,但由于受天气预报准确率的影响,部分区域雪灾预估等级出现偏差。

公众天气预报服务满意度的影响因素——基于决策树的实证研究

在全国范围内抽取11180个样本,对天气预报服务的满意度及其影响因素进行调查研究。结果发现,人们对天气预报服务的总体满意度较高。经决策树分析,在选取的15个可能的影响因素中,有7个因素对于天气预报服务满意度具有重要影响,依次是天气预警信号及时性、天气预警信号准确性、天气信息每日更新频次、未来三天天气预报准确性、天气预报用语的通俗性、24小时天气预报准确性、个人所在省份。要提高公众对于天气预报服务的满意度,进而提高公众对天气预报的关注度,就要保证天气预警的及时性,提高更新频率,并保证天气预警的准确性和未来三天天气预报的准确性。