High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle datase...High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16–17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C,respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C(19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.展开更多
为了提升导弹在复杂环境下的寻的制导能力,设计了一种红外与可见光双模式导引头光学系统。该方案中采用分光镜透射红外光反射可见光,使结构布局更加紧凑,实现红外与可见光共口径,同时配合红外材料选取,实现光学被动消热差设计。中红外...为了提升导弹在复杂环境下的寻的制导能力,设计了一种红外与可见光双模式导引头光学系统。该方案中采用分光镜透射红外光反射可见光,使结构布局更加紧凑,实现红外与可见光共口径,同时配合红外材料选取,实现光学被动消热差设计。中红外模式视场角3°×2.3°,可见光模式视场角5°×4°,工作温度20℃条件下,双模式在截止频率处,MTF(Modulation Transfer Function)值均大于0.4。红外与可见光双模式光学系统适合应用于复杂环境的导弹制导,对温度有良好的适应性,具有较好的成像质量,满足系统的性能要求。展开更多
由于复合高温干旱事件造成的综合效应远超普通干旱事件,复合高温干旱日益受到人们关注。基于中亚地区1981—2020年欧洲中期天气预报中心的第五代再分析陆地产品(Land Component of the Fifth Generation of European Reanalysis,ERA5-La...由于复合高温干旱事件造成的综合效应远超普通干旱事件,复合高温干旱日益受到人们关注。基于中亚地区1981—2020年欧洲中期天气预报中心的第五代再分析陆地产品(Land Component of the Fifth Generation of European Reanalysis,ERA5-Land)的逐小时温度数据、月尺度潜在蒸散量数据和日尺度多源集成降水产品,计算标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)和日最高温度,识别复合高温干旱事件并分析其特征,得到以下结论:(1)复合高温干旱事件在中亚各地区空间分布上呈非集中趋势,1980年代、1990年代、2000年代和2010年代发生频次较高的区域分别位于东南部、北部、西北部和西部;(2)这些事件的时间分布表现出由大波动变为平稳小波动的趋势,且2020年之后将维持此平稳状态;(3)分析1984、1993、2010、2020年4个复合高温干旱事件典型年份,发现1984年高温干旱主要集中在中亚东南部,1993年仅零星地区偶发,2010年北部多发复合高温干旱事件,2020年则集中于西部地区。展开更多
This study focuses on the impact of climate change, specifically the increasing threat of heatwaves, in Pakistan, with a particular emphasis on the city of Karachi. The Pakistan Meteorological Department (PMD) analyse...This study focuses on the impact of climate change, specifically the increasing threat of heatwaves, in Pakistan, with a particular emphasis on the city of Karachi. The Pakistan Meteorological Department (PMD) analysed a century of climatic data to reveal warming trends, attributing them to human-induced factors. The vulnerability of Pakistan to climate change is highlighted, given its warm climate and location in a region where temperature increases are expected to surpass global averages. The study examines the past three decades, noting a significant rise in the frequency of hot days, especially in Karachi, where heatwaves have become more prevalent. The aims and objectives of the study involve identifying temporal changes in temperature, rainfall, humidity, and wind speed from 1984 to 2014 in Karachi. The literature review emphasizes the health implications of heatwaves, citing increased mortality during such events globally. The study incorporates a comprehensive temporal analysis, addressing gaps in previous research by considering multiple climate indicators responsible for heatwaves. The methodology involves statistical analyses, including linear regression and Pearson correlation, applied to temperature data and urbanization parameters. Results indicate an increasing trend in heat index temperature, with heatwave vulnerability peaking in the last three decades. Heat Index Temperature Anomalies show a clear surge, emphasizing the need for new indices to control critical heat stress conditions. The study concludes that tropical climate variability, particularly heat index, is linked to extreme hot days, urging measures to reduce population vulnerability. The findings underscore the importance of policy strategies, such as integrated coastal zone management, to mitigate the adverse health effects of heatwaves in Karachi’s vulnerable population.展开更多
基金supported by the Korea Meteorological Administration Research and Development Program’s‘Research and Development for KMA Weather,Climate,and Earth system Services-Development and Application of Monitoring,Analysis and Prediction Technology for HighImpact Weather’[KMA2018-00123]
文摘High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16–17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C,respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C(19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.
文摘为了提升导弹在复杂环境下的寻的制导能力,设计了一种红外与可见光双模式导引头光学系统。该方案中采用分光镜透射红外光反射可见光,使结构布局更加紧凑,实现红外与可见光共口径,同时配合红外材料选取,实现光学被动消热差设计。中红外模式视场角3°×2.3°,可见光模式视场角5°×4°,工作温度20℃条件下,双模式在截止频率处,MTF(Modulation Transfer Function)值均大于0.4。红外与可见光双模式光学系统适合应用于复杂环境的导弹制导,对温度有良好的适应性,具有较好的成像质量,满足系统的性能要求。
文摘由于复合高温干旱事件造成的综合效应远超普通干旱事件,复合高温干旱日益受到人们关注。基于中亚地区1981—2020年欧洲中期天气预报中心的第五代再分析陆地产品(Land Component of the Fifth Generation of European Reanalysis,ERA5-Land)的逐小时温度数据、月尺度潜在蒸散量数据和日尺度多源集成降水产品,计算标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)和日最高温度,识别复合高温干旱事件并分析其特征,得到以下结论:(1)复合高温干旱事件在中亚各地区空间分布上呈非集中趋势,1980年代、1990年代、2000年代和2010年代发生频次较高的区域分别位于东南部、北部、西北部和西部;(2)这些事件的时间分布表现出由大波动变为平稳小波动的趋势,且2020年之后将维持此平稳状态;(3)分析1984、1993、2010、2020年4个复合高温干旱事件典型年份,发现1984年高温干旱主要集中在中亚东南部,1993年仅零星地区偶发,2010年北部多发复合高温干旱事件,2020年则集中于西部地区。
文摘This study focuses on the impact of climate change, specifically the increasing threat of heatwaves, in Pakistan, with a particular emphasis on the city of Karachi. The Pakistan Meteorological Department (PMD) analysed a century of climatic data to reveal warming trends, attributing them to human-induced factors. The vulnerability of Pakistan to climate change is highlighted, given its warm climate and location in a region where temperature increases are expected to surpass global averages. The study examines the past three decades, noting a significant rise in the frequency of hot days, especially in Karachi, where heatwaves have become more prevalent. The aims and objectives of the study involve identifying temporal changes in temperature, rainfall, humidity, and wind speed from 1984 to 2014 in Karachi. The literature review emphasizes the health implications of heatwaves, citing increased mortality during such events globally. The study incorporates a comprehensive temporal analysis, addressing gaps in previous research by considering multiple climate indicators responsible for heatwaves. The methodology involves statistical analyses, including linear regression and Pearson correlation, applied to temperature data and urbanization parameters. Results indicate an increasing trend in heat index temperature, with heatwave vulnerability peaking in the last three decades. Heat Index Temperature Anomalies show a clear surge, emphasizing the need for new indices to control critical heat stress conditions. The study concludes that tropical climate variability, particularly heat index, is linked to extreme hot days, urging measures to reduce population vulnerability. The findings underscore the importance of policy strategies, such as integrated coastal zone management, to mitigate the adverse health effects of heatwaves in Karachi’s vulnerable population.
