Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion produ...Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion product to quantify the kinematic features of sea ice in the Arctic outflow region which specially referred to the Fram Strait and to the north of the Northeast Passage(NEP). An observed trend of increased southward sea ice displacement from the central Arctic to the Fram Strait indicated enhancement of the Transpolar Drift Stream(TDS). In the regions to the north of the NEP, the long-term trend of northward sea ice speed in the Kara sector was +0.04 cm/s per year in spring. A significant statistical relationship was found between the NEP open period and the northward speed of the sea ice to the north of the NEP. The offshore advection of sea ice could account for the opening of sea routes by 33% and 15% in the Kara and Laptev sectors, respectively. The difference in sea level pressure across the TDS,i.e., the Central Arctic Index(CAI), presented more significant correlation than for the Arctic atmospheric Dipole Anomaly index with the open period of the NEP, and the CAI could explain the southward displacement of sea ice toward the Fram Strait by more than 45%. The impact from the summer positive CAI reinforces the thinning and mechanical weakening of the sea ice in the NEP region, which improves the navigability of the NEP.展开更多
北极东北航道起始段海域位于我国黄渤海,大风和强降水是可能威胁到该海域航运安全的主要灾害性天气类型。其中寒潮天气过程伴随的冷空气大风以及热带气旋、温带气旋等天气系统产生的大风、强降水等灾害性天气,对该海域航运安全造成很大...北极东北航道起始段海域位于我国黄渤海,大风和强降水是可能威胁到该海域航运安全的主要灾害性天气类型。其中寒潮天气过程伴随的冷空气大风以及热带气旋、温带气旋等天气系统产生的大风、强降水等灾害性天气,对该海域航运安全造成很大影响。利用1991—2020年美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)全球逐日再分析资料,分析了北极东北航道适航期(7—10月)Rossby波沿高空急流能量传播特征及其对北极东北航道起始段海域天气的影响,特别是对强降水的影响。结果表明:(1)沿北半球副热带地区250hPa高空西风急流轴经向风表现为纬向三波型准静止的Rossby波形态;(2)高空250hPa大气准静止Rossby波波源位于地中海地区,波动在此激发并沿急流向东传播,传播过程中波动能量耗散,但波源即地中海地区能量的不断注入,使其得以维持和加强;(3)波作用通量散度指数与北极东北航道起始段海域降水量、风速相关系数绝对值达0.5以上,其中位于我国东北部至鄂霍茨克海地区的波作用通量指数与降水量和风速相关系数的绝对值均接近0.9,属于强相关,说明Rossby波沿高空急流传播时能量汇集、加强,对北极东北航道起始段海域的降水量、风速影响较大,从而可触发强降水、大风等灾害性天气;(4)当Rossby波扰动偏强时,向下游传播能量偏强,则西风急流加强,垂直上升运动增强,导致北极东北航道起始段海域降水异常偏多。展开更多
Remote sensing data from passive microwave and satellite-based altimeters, associated with the data measured underway, were used to characterize seasonal and spatial changes in sea ice conditions along the Arctic Nort...Remote sensing data from passive microwave and satellite-based altimeters, associated with the data measured underway, were used to characterize seasonal and spatial changes in sea ice conditions along the Arctic Northeast Passage （NEP） and the high-latitude sea route （HSR） north of the island groups in the eastern Arctic Ocean in 2007 and 2012. In both years, summer Arctic sea ice extent reached minima since satellite records began in 1979. However, there were large differences in spatial distribution of sea ice between the two years. Sea ice conditions in the eastern sections of the sea routes were relatively slight in the 2007 summer, because of the remarkable decline of sea ice in the Pacific sector. A belt of sea ice that blocked sections from the western Laptev Sea to the eastern Kara Sea resulted in both sea routes not completely opening through the 2007 summer. The combination of a great storm in early August causing sea ice to be sheared from the Arctic pack ice and the thick ice surviving the winter delayed the summer opening of the eastern parts of the sea routes in 2012. However, the average open period, defined by 50% ice concentration for the entire NEP and HSR, reached 82 d and 55 d, respectively. Thus, 2012 was the most accessible year since the satellite era began in 1979. The distinct decrease in sea ice in the western parts of the HSR in the 2012 summer can be attributed to the thinning preconditions of sea ice prior to the melt season. The HSR opening can benefit Arctic shipping of deeper-draft vessels.展开更多
基金The National Key Research and Development Program of China under contract Nos 2018YFA0605903 and 2016YFC14003the National Natural Science Foundation of China under contract No.41722605
文摘Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion product to quantify the kinematic features of sea ice in the Arctic outflow region which specially referred to the Fram Strait and to the north of the Northeast Passage(NEP). An observed trend of increased southward sea ice displacement from the central Arctic to the Fram Strait indicated enhancement of the Transpolar Drift Stream(TDS). In the regions to the north of the NEP, the long-term trend of northward sea ice speed in the Kara sector was +0.04 cm/s per year in spring. A significant statistical relationship was found between the NEP open period and the northward speed of the sea ice to the north of the NEP. The offshore advection of sea ice could account for the opening of sea routes by 33% and 15% in the Kara and Laptev sectors, respectively. The difference in sea level pressure across the TDS,i.e., the Central Arctic Index(CAI), presented more significant correlation than for the Arctic atmospheric Dipole Anomaly index with the open period of the NEP, and the CAI could explain the southward displacement of sea ice toward the Fram Strait by more than 45%. The impact from the summer positive CAI reinforces the thinning and mechanical weakening of the sea ice in the NEP region, which improves the navigability of the NEP.
文摘北极东北航道起始段海域位于我国黄渤海,大风和强降水是可能威胁到该海域航运安全的主要灾害性天气类型。其中寒潮天气过程伴随的冷空气大风以及热带气旋、温带气旋等天气系统产生的大风、强降水等灾害性天气,对该海域航运安全造成很大影响。利用1991—2020年美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)全球逐日再分析资料,分析了北极东北航道适航期(7—10月)Rossby波沿高空急流能量传播特征及其对北极东北航道起始段海域天气的影响,特别是对强降水的影响。结果表明:(1)沿北半球副热带地区250hPa高空西风急流轴经向风表现为纬向三波型准静止的Rossby波形态;(2)高空250hPa大气准静止Rossby波波源位于地中海地区,波动在此激发并沿急流向东传播,传播过程中波动能量耗散,但波源即地中海地区能量的不断注入,使其得以维持和加强;(3)波作用通量散度指数与北极东北航道起始段海域降水量、风速相关系数绝对值达0.5以上,其中位于我国东北部至鄂霍茨克海地区的波作用通量指数与降水量和风速相关系数的绝对值均接近0.9,属于强相关,说明Rossby波沿高空急流传播时能量汇集、加强,对北极东北航道起始段海域的降水量、风速影响较大,从而可触发强降水、大风等灾害性天气;(4)当Rossby波扰动偏强时,向下游传播能量偏强,则西风急流加强,垂直上升运动增强,导致北极东北航道起始段海域降水异常偏多。
基金supported financially by the grants from the National Natural Science Foundation of China(Grant nos.41106160,41476170)the Chinese Polar Environment Comprehensive Investigation and Assessment Programs(Grant nos.CHINARE2014-0403,CHINARE 2014-04-04,CHINARE2014-03-01)the Ocean Public Welfare Scientific Research Project of China(Grant no.201205007)
文摘Remote sensing data from passive microwave and satellite-based altimeters, associated with the data measured underway, were used to characterize seasonal and spatial changes in sea ice conditions along the Arctic Northeast Passage （NEP） and the high-latitude sea route （HSR） north of the island groups in the eastern Arctic Ocean in 2007 and 2012. In both years, summer Arctic sea ice extent reached minima since satellite records began in 1979. However, there were large differences in spatial distribution of sea ice between the two years. Sea ice conditions in the eastern sections of the sea routes were relatively slight in the 2007 summer, because of the remarkable decline of sea ice in the Pacific sector. A belt of sea ice that blocked sections from the western Laptev Sea to the eastern Kara Sea resulted in both sea routes not completely opening through the 2007 summer. The combination of a great storm in early August causing sea ice to be sheared from the Arctic pack ice and the thick ice surviving the winter delayed the summer opening of the eastern parts of the sea routes in 2012. However, the average open period, defined by 50% ice concentration for the entire NEP and HSR, reached 82 d and 55 d, respectively. Thus, 2012 was the most accessible year since the satellite era began in 1979. The distinct decrease in sea ice in the western parts of the HSR in the 2012 summer can be attributed to the thinning preconditions of sea ice prior to the melt season. The HSR opening can benefit Arctic shipping of deeper-draft vessels.
