本文对2023年12月旅顺出现的连续10天强降雪天气事件进行回顾,运用多个站点观测资料、ERA5的位势高度场、海表温度场、中央气象台的天气形势图与近10年12月连续降雪事件加以对比总结,结果表明:2023年12月平均的冷涡强度最强(中心强度为5...本文对2023年12月旅顺出现的连续10天强降雪天气事件进行回顾,运用多个站点观测资料、ERA5的位势高度场、海表温度场、中央气象台的天气形势图与近10年12月连续降雪事件加以对比总结,结果表明:2023年12月平均的冷涡强度最强(中心强度为5080位势米),强大的冷涡以及极为偏东的高空冷空气堆积是此次连续降雪事件的主要系统;渤海海峡的等温线分布有一个明显的向渤海以北延伸的暖舌(5.2℃~7.6℃之间),平均海气温差在9.4℃,这样冷空气在经过上游暖舌区域增温增湿后可给辽东半岛带来冷流降雪;此次连续降雪既有系统性降雪,又有冷流性降雪,其中冷流降雪(旅顺地区风速小),850 hpa或700 hpa分别处在涡后或槽后脊前,系统性降雪,500 hpa、700 hpa我区均处于高空槽前,850 hpa处于槽后脊前;冷流降雪前及过程中,辽东半岛北部中低空都出现了明显的垂直运动、水汽输送、水汽辐合,700 hpa相较850 hpa更为明显。In this paper, the 10 consecutive days of heavy snowfall in Lvshun in December 2023 was reviewed, and the observation data of several stations, the geopotential height field of ERA5, the sea surface temperature field, and the weather situation chart of the National Meteorological Center of CMA were compared with the continuous snowfall events in December in recent 10 years. The results show that: In December 2023, the average intensity of the cold vortex is the strongest (the central intensity is 5080 geopotential meters), and the strong cold vortex and the accumulation of high altitude cold air very far to the east are the main systems of this continuous snowfall event. The isothermal distribution of the strait has an obvious warm tongue (between 5.2˚C~7.6˚C) extending to the north of the Bohai Sea, the average temperature difference between the sea and the air is 9.4˚C, so that the cold air can bring cold flow snow to the Liaodong Peninsula after warming and humidification in the upstream warm tongue area. The continuous snowfall has both systematic snowfall and cold flow snowfall, among which cold flow snowfall (low wind speed in the Lvshun area), 850 hpa or 700 hpa are behind the vortex or in front of the rear ridge of the trough, and systematic snowfall, 500 hpa and 700 hpa are in front of the upper trough, and 850 hpa is in front of the rear ridge of the trough. Before and during the cold current snowfall, there are obvious vertical movements, water vapor transport and water vapor convergence in the middle and low levels in the northern part of the Liaodong Peninsula, the phenomenon is more pronounced at 700 hpa than 850 hpa.展开更多
为进一步增强对青藏高原降雪机制和影响因素的认识,丰富对高原气候系统的理解,本文基于4个国内的CMIP6 (Coupled Model Intercomparison Project in Phase 6)模式模拟资料以及欧洲中期天气预报中心(ECMWF)的ERA5再分析资料,对青藏高原...为进一步增强对青藏高原降雪机制和影响因素的认识,丰富对高原气候系统的理解,本文基于4个国内的CMIP6 (Coupled Model Intercomparison Project in Phase 6)模式模拟资料以及欧洲中期天气预报中心(ECMWF)的ERA5再分析资料,对青藏高原降雪的时空变化特征进行分析,并评估青藏高原在当前气候情景下的降雪变化。结果表明:(1) 4个模式和ERA5模拟的降雪空间分布存在不同程度的差异,除BCC-ESM1外,其他3个模式和ERA5模拟出在高原东南部都存在降雪大值区,而BCC-ESM1模式在模拟高原西部地区时出现了大值中心;(2) 从空间分布趋势来看,BCC-CSM2-MR、FGOALS-f3-L、FIO-ESM-2-0模拟出高原大部分地区降雪存在减少趋势,但FIO-ESM-2-0模拟出降雪在高原东南部减少更为显著。ERA5模拟出高原东部和西部地区降雪均在增加。从时间上看,仅有FIO-ESM-2-0模拟的降雪呈现较为明显的减少特征;(3) 在春季,FIO-ESM-2-0模拟的降雪年际变化没有显著增减趋势;BCC-CSM2-MR、BCC-ESM1和FGOALS-f3-L模拟的均为弱的增加趋势。而在冬季,BCC-CSM2-MR和BCC-ESM1模拟的降雪无明显增减趋势,仅有FIO-ESM-2-0模拟的呈明显减少趋势;(4) 4个模式中青藏高原降雪年内变化均表现为“双峰”型,峰值分别在春季和秋季,且春季大于秋季。ERA5的年内变化趋势与模式一致,但变化相比更平缓。展开更多
Air blasts induced by rock-ice avalanches are common natural phenomena known for their far-field destructive impact.In this study,remote sensing images,eyewitness videos and numerical modelling were comprehensively ap...Air blasts induced by rock-ice avalanches are common natural phenomena known for their far-field destructive impact.In this study,remote sensing images,eyewitness videos and numerical modelling were comprehensively applied to analyze the initiation and propagation of the 2021 Chamoli avalancheinduced air blast.Our findings indicate that air blasts are observed from the avalanche source area to the Rishiganga valley,but nearly disappear in the Dhauliganga valley.The most intense air blast is concentrated on the left side of Ronti Gad valley,with maximum velocity and pressure estimated at over 70 m/s and 20 kPa,respectively.Such high pressure results in widespread tree breakage in the area.Based on the analysis of the Chamoli event,we further discussed the potential contribution of the avalanche flow regime,avalanche dynamics and geomorphology to the destructive potential of air blasts.Rapidly moved sliding mass can impart the air blast a high initial momentum,and this process will be exaggerated when the avalanche impacts valley walls at bends.However,when the rock-ice avalanche transforms into a debris-enriched flash flood,free water within the flowing mass can displace air,inhibiting the generation of air blasts.Our work offers new insights into the generation and propagation of rock-ice avalanche-induced air blasts,underscoring the importance of including this type of hazard during avalanche risk assessment in high-altitude glacial regions.展开更多
文摘本文对2023年12月旅顺出现的连续10天强降雪天气事件进行回顾,运用多个站点观测资料、ERA5的位势高度场、海表温度场、中央气象台的天气形势图与近10年12月连续降雪事件加以对比总结,结果表明:2023年12月平均的冷涡强度最强(中心强度为5080位势米),强大的冷涡以及极为偏东的高空冷空气堆积是此次连续降雪事件的主要系统;渤海海峡的等温线分布有一个明显的向渤海以北延伸的暖舌(5.2℃~7.6℃之间),平均海气温差在9.4℃,这样冷空气在经过上游暖舌区域增温增湿后可给辽东半岛带来冷流降雪;此次连续降雪既有系统性降雪,又有冷流性降雪,其中冷流降雪(旅顺地区风速小),850 hpa或700 hpa分别处在涡后或槽后脊前,系统性降雪,500 hpa、700 hpa我区均处于高空槽前,850 hpa处于槽后脊前;冷流降雪前及过程中,辽东半岛北部中低空都出现了明显的垂直运动、水汽输送、水汽辐合,700 hpa相较850 hpa更为明显。In this paper, the 10 consecutive days of heavy snowfall in Lvshun in December 2023 was reviewed, and the observation data of several stations, the geopotential height field of ERA5, the sea surface temperature field, and the weather situation chart of the National Meteorological Center of CMA were compared with the continuous snowfall events in December in recent 10 years. The results show that: In December 2023, the average intensity of the cold vortex is the strongest (the central intensity is 5080 geopotential meters), and the strong cold vortex and the accumulation of high altitude cold air very far to the east are the main systems of this continuous snowfall event. The isothermal distribution of the strait has an obvious warm tongue (between 5.2˚C~7.6˚C) extending to the north of the Bohai Sea, the average temperature difference between the sea and the air is 9.4˚C, so that the cold air can bring cold flow snow to the Liaodong Peninsula after warming and humidification in the upstream warm tongue area. The continuous snowfall has both systematic snowfall and cold flow snowfall, among which cold flow snowfall (low wind speed in the Lvshun area), 850 hpa or 700 hpa are behind the vortex or in front of the rear ridge of the trough, and systematic snowfall, 500 hpa and 700 hpa are in front of the upper trough, and 850 hpa is in front of the rear ridge of the trough. Before and during the cold current snowfall, there are obvious vertical movements, water vapor transport and water vapor convergence in the middle and low levels in the northern part of the Liaodong Peninsula, the phenomenon is more pronounced at 700 hpa than 850 hpa.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2244227,42277126 and 41977215).
文摘Air blasts induced by rock-ice avalanches are common natural phenomena known for their far-field destructive impact.In this study,remote sensing images,eyewitness videos and numerical modelling were comprehensively applied to analyze the initiation and propagation of the 2021 Chamoli avalancheinduced air blast.Our findings indicate that air blasts are observed from the avalanche source area to the Rishiganga valley,but nearly disappear in the Dhauliganga valley.The most intense air blast is concentrated on the left side of Ronti Gad valley,with maximum velocity and pressure estimated at over 70 m/s and 20 kPa,respectively.Such high pressure results in widespread tree breakage in the area.Based on the analysis of the Chamoli event,we further discussed the potential contribution of the avalanche flow regime,avalanche dynamics and geomorphology to the destructive potential of air blasts.Rapidly moved sliding mass can impart the air blast a high initial momentum,and this process will be exaggerated when the avalanche impacts valley walls at bends.However,when the rock-ice avalanche transforms into a debris-enriched flash flood,free water within the flowing mass can displace air,inhibiting the generation of air blasts.Our work offers new insights into the generation and propagation of rock-ice avalanche-induced air blasts,underscoring the importance of including this type of hazard during avalanche risk assessment in high-altitude glacial regions.
