By using the Arctic runoff data from R-ArcticNET V4.0 and ArcticRIMS,trends of four major rivers flowing into the Arctic Ocean,whose climate factor plays an important role in determining the variability of the Arctic ...By using the Arctic runoff data from R-ArcticNET V4.0 and ArcticRIMS,trends of four major rivers flowing into the Arctic Ocean,whose climate factor plays an important role in determining the variability of the Arctic runoff,are investigated.The results show that for the past 30 years,the trend of the Arctic runoff is seasonally dependent.There is a significant trend in spring and winter and a significant decreasing trend in summer,leading to the reduced seasonal cycle.In spring,surface air temperature is the dominant factor influencing the four rivers.In summer,precipitation is the most important factor for Lena and Mackenzie,while snow cover is the most important factor for Yenisei and Ob.For Mackenzie,atmospheric circulation does play an important role for all the seasons,which is not the case for the Eurasian rivers.The authors further discuss the relationships between the Arctic runoff and sea ice.Significant negative correlation is found at the mouth of the rivers into the Arctic Ocean in spring,while significant positive correlation is observed just at the north of the mouths of the rivers into the Arctic in summer.In addition,each river has different relationship with sea ice in the eastern Greenland Sea.展开更多
Severe hypoxia was observed in the submarine canyon to the east of the Changjiang estuary in July 14, 2015, two days after typhoon Chan-hom. The oxygen concentration reached as low as 2.0 mg/L and occupied a water col...Severe hypoxia was observed in the submarine canyon to the east of the Changjiang estuary in July 14, 2015, two days after typhoon Chan-hom. The oxygen concentration reached as low as 2.0 mg/L and occupied a water column of about 25 m. A ROMS model was con?gured to explore the underlying physical processes causing the formation of hypoxia. Chan-hom passed through the Changjiang estuary during the neap tide. The strati?cation was completely destroyed in the shallow nearshore region when typhoon passing. However, it was maintained in the deep canyon, though the surface mixed layer was largely deepened. The residual water in the deep canyon is considered to be the possible source of the later hypoxia. After Chan-hom departure, not only the low salinity plume water spread further of fshore, but also the sea surface temperature(SST) rewarmed quickly. Both changes helped strengthen the strati?cation and facilitate the formation of hypoxia. It was found that the surface heat ?ux, especially the solar short wave radiation dominated the surface re-warming, the of fshore advection of the warmer Changjiang Diluted Water(CDW) also played a role. In addition to the residual water in the deep canyon, the Taiwan Warm Current(TWC) was found to ?ow into the deep canyon pre-and soon post-Chan-hom, which was considered to be the original source of the hypoxia water.展开更多
基金The National Natural Science Foundation of China under contract Nos 40676003 and 40876099the National Basic Research Program of China under contract No. 2006CB403605+1 种基金"Hundred Talent Program" of the Chinese Academy of Sciences,the China Meteorological Administration under contract No. GYHY200806006the National Key Technology R&D Program under contract No. 2008AA121704
文摘By using the Arctic runoff data from R-ArcticNET V4.0 and ArcticRIMS,trends of four major rivers flowing into the Arctic Ocean,whose climate factor plays an important role in determining the variability of the Arctic runoff,are investigated.The results show that for the past 30 years,the trend of the Arctic runoff is seasonally dependent.There is a significant trend in spring and winter and a significant decreasing trend in summer,leading to the reduced seasonal cycle.In spring,surface air temperature is the dominant factor influencing the four rivers.In summer,precipitation is the most important factor for Lena and Mackenzie,while snow cover is the most important factor for Yenisei and Ob.For Mackenzie,atmospheric circulation does play an important role for all the seasons,which is not the case for the Eurasian rivers.The authors further discuss the relationships between the Arctic runoff and sea ice.Significant negative correlation is found at the mouth of the rivers into the Arctic Ocean in spring,while significant positive correlation is observed just at the north of the mouths of the rivers into the Arctic in summer.In addition,each river has different relationship with sea ice in the eastern Greenland Sea.
基金Supported by the National Key Research and Development Program of China(No.2016YFC1402000)the National Natural Science Foundation of China(Nos.41406008,41706022)+2 种基金the Fundamental Research Funds for the Central Universities(No.201762032)the Natural Science Foundation of Shandong Province(No.ZR2014DQ023)the SRF for ROCS,SEM[2014] No.1685
文摘Severe hypoxia was observed in the submarine canyon to the east of the Changjiang estuary in July 14, 2015, two days after typhoon Chan-hom. The oxygen concentration reached as low as 2.0 mg/L and occupied a water column of about 25 m. A ROMS model was con?gured to explore the underlying physical processes causing the formation of hypoxia. Chan-hom passed through the Changjiang estuary during the neap tide. The strati?cation was completely destroyed in the shallow nearshore region when typhoon passing. However, it was maintained in the deep canyon, though the surface mixed layer was largely deepened. The residual water in the deep canyon is considered to be the possible source of the later hypoxia. After Chan-hom departure, not only the low salinity plume water spread further of fshore, but also the sea surface temperature(SST) rewarmed quickly. Both changes helped strengthen the strati?cation and facilitate the formation of hypoxia. It was found that the surface heat ?ux, especially the solar short wave radiation dominated the surface re-warming, the of fshore advection of the warmer Changjiang Diluted Water(CDW) also played a role. In addition to the residual water in the deep canyon, the Taiwan Warm Current(TWC) was found to ?ow into the deep canyon pre-and soon post-Chan-hom, which was considered to be the original source of the hypoxia water.
