During years 1980/1981-2012/2013, inter-annual variations in sea ice and snow thickness in Kemi, in the northern coast of the Gulf of Bothnia, Baltic Sea, depended on the air temperature, snow fall, and rain. Inter-an...During years 1980/1981-2012/2013, inter-annual variations in sea ice and snow thickness in Kemi, in the northern coast of the Gulf of Bothnia, Baltic Sea, depended on the air temperature, snow fall, and rain. Inter-annual variations in the November--April mean air temperature, accumulated total precipitation, snow fall, and rain, as well as ice and snow thickness in Kemi and ice concentration in the Gulf of Bothnia correlated with inter-annual variations of the Pacific Decadal Oscillation （PDO）, Arctic Oscillation （AO）, North Atlantic Oscillation （NAO）, Scandinavian Pattern （SCA）, and Polar / Eurasian Pattern （PEU）. The strong role of PDO is a new finding. In general, the relationships with PDO were approximately equally strong as those with AO, but rain and sea ice concentration were better correlated with PDO. The correlations with PDO were, however, not persistent; for a study period since 1950 the correlations were much lower. During 1980/1981--2012/2013, also the Pacific / North American Pattern （PNA） and E1 Nino-Southern Oscillation （ENSO） had statistical connections with the conditions in the Gulf of Bothnia, revealed by analyzing their effects combined with those of PDO and AO. A reduced autumn sea ice area in the Arctic was related to increased rain and total precipitation in the following winter in Kemi. This correlation was significant for the Pan-Arctic sea ice area in September, October, and November, and for the November sea ice area in the Barents / Kara seas.展开更多
To study effects of variations in climate-marine environment in the Arctic Ocean on ecology,based on the actual and reestablished data by biomarkers of algae in sediment in 1997,1999,2003,2008,and 2010,the interannual...To study effects of variations in climate-marine environment in the Arctic Ocean on ecology,based on the actual and reestablished data by biomarkers of algae in sediment in 1997,1999,2003,2008,and 2010,the interannual and spatial variations of phytoplankton,zooplankton and chlorophyll a concentration in the Chukchi Sea and the Bering Sea as well as their relations to El Nino-Southern Oscillation( ENSO) and Arctic Oscillation( AO) were analyzed. The results show that there were spatial and temporal anomalies in the phytoplankton community structure reestablished by biomarkers of algae in the Chukchi Sea and the Bering Sea in 1999 and 2010. The total content of biomarkers( brassicasterol,dinosterol,C37 alkenones and chlesterol) in sediment collected in 2010 was far lower than that in 1999,but brassicasterol was dominant in the two years,that is,diatom was dominant,which was consistent with the actual structure and distribution of phytoplankton community in 1999 and 2010; there were great changes in the dominant species of plankton in the two seas in 1999 and 2010,which could be regarded as the ecological response of the North Pole under the background of global warming. Chlorophyll a concentration in the water of the Bering Sea was 0. 720 μg/dm^3 at 0 m and 0. 765μg/dm^3 at 10 m in 1997 and 0. 723 μg/dm^3 at 0 m and 0. 731 μg/dm^3 at 10 m in 2003,and the concentration was very close to each other,which was affected by El Ni1 o and the negative phase of AO. It was 0. 395 μg/dm^3 at 0 m in 1999 and 0. 399 μg/dm^3 at 0 m and 0. 357 μg/dm^3 at 10 m in 2008,which was influenced by La Ni1 a and the positive phase of AO. The phases and intensity of AO and ENSO had various effects on the quantity and dominant species of phytoplankton and zooplankton in the Chukchi Sea and the Bering Sea. During the period of AO with positive or negative phase and El Ni1o( in 1997 and 2003),their combination was favorable to the growth of phytoplankton and zooplankton,while the combination of negative phase of AO and La Nina( in 2010) had adverse effects on the growth of phytoplankton. The combination of AO with positive phase and strong La Nina( in 1999 and 2008) had small effects on phytoplankton community.展开更多
The marine environment of North Sea and Baltic is one of the most heavily strained by numerous human activities. Simultaneously water and air temperatures increase more than elsewhere in Europe and globally, which can...The marine environment of North Sea and Baltic is one of the most heavily strained by numerous human activities. Simultaneously water and air temperatures increase more than elsewhere in Europe and globally, which cannot be explained with ＂global warming＂. The climatic change issue would be better understood if this extraordinary regional warming is sufficiently explained. The regional features are unique for in-depth studies due to different summer-winter conditions, shallowness of the seas, geographical structure, and main pathway for maritime weather patterns moving eastwards. The impact of sea activities on the seasonal sea water profile structure is contributing to stronger regional warming, change in growing season, and less severe sea ice conditions. The impact of the man, whether small or large, should be understood very soon and very thoroughly.展开更多
The flood and drought across the Yangtze and Huaihe River（Jianghuai） areas are frequent in summer, especially in June and July.Therefore,predicting the summer flood and drought in the Jianghuai region is always one ...The flood and drought across the Yangtze and Huaihe River（Jianghuai） areas are frequent in summer, especially in June and July.Therefore,predicting the summer flood and drought in the Jianghuai region is always one of the key topics concerned by meteorologists in China.Previous studies focused more on the skin temperature anomalies in a local area,and paid less attention to the connections between the anomalies of land-sea thermal contrast in remote continents and the summer flood and drought in Jianghuai areas of China.By using the US NCEP/NCAR monthly mean reanalysis data and the rainfall data at 743 stations in China,based on the interdecadal variation characteristics of the flood and drought index（FDI） during 51 yr （1954-2004） in the Jianghuai region of China in summer,the North African areas have been selected as the key regions for the correlation analysis.The results show that the surface temperature anomalies in the key regions have good continuity in winter,and the winter North Atlantic Oscillation（NAO） is perhaps one of the important factors that bring about the continuity of the anomalies.By a singular value decomposition（SVD） analysis between the skin temperature in the previous winter in North Africa and the summer rainfall in the Jianghuai region,it is found that when the North African continent is colder（warmer） and its northwestern sea is warmer（colder）,the rainfall increases（decreases） in the Jianghuai region in summer generally.Further analysis finds that the anomaly of the surface temperature contrast between sea and land in North Africa has a good indication for the summer flood and drought in the Jianghuai areas of China.Therefore,a sea and land thermal contrast index（SLTCI） is defined to reflect the intensity of the large-scale land-sea thermal contrast.A positive correlation between the SLTCI in North Africa and the summer FDI in Jianghuai areas is identified,and it can well indicate the extreme flood and drought situations in the Jianghuai region of China.展开更多
Using the alkenone paleotemperature index U k 37′, a high-resolution sea surface temperature (SST) record since 3600 a BP was reconstructed from the mud area in the north of the East China Sea. Combining with the gra...Using the alkenone paleotemperature index U k 37′, a high-resolution sea surface temperature (SST) record since 3600 a BP was reconstructed from the mud area in the north of the East China Sea. Combining with the grain size distribution curve of sensitive grain size group, which may reflect the East Asia Winter Monsoon activity, the palaeoenvironmental evolution cycle throughout the late Holocene in the area was obtained. The marine environment evolution during the last 3600 years displays a five-stage trend. (1) Temperature descending period from 0.85 cal. ka BP to present. The maximum temperature decrease amplitude is 2℃. The winter monsoon intensified and ‘Little Ice Age’ were recorded in this period. (2) Warming period from 1.90 to 0.85 cal. ka BP. The mean temperature increase amplitude is 0.8℃. The Sui-Tang warming period was recorded at about 0.85―1.35 cal. ka BP and a prominent cooling event was recorded at 1.4 cal. ka BP in this period. (3) Temperature descending period from 2.55 to 1.90 cal. ka BP. Temperature cooling amplitude is 0.9℃. This period is coincident with an integrated temperature circle recorded in the Antarctic ice core, with the temperature changes from a slow cooling stage to a rapid warming stage. (4) Temperature comparatively stable with a little ascending period from 3.2 to 2.55 cal. ka BP. Temperature warming amplitude is 0.3℃. This period is coincident with the temperature fluctuant ascending period recorded in Antarctic ice core. (5) Temperature comparatively stable with little descending period from 3.6 to 3.2 cal. ka BP. This period corresponds with the temperature fluctuant cooling period recorded in Antarctic ice core. Basically, those five periods were coincident with the Antarctic ice core record. During the global cooling stage, the SST change in the continental shelf sea can be adjusted simultaneously.展开更多
基金supported by the Academy of Finland (Grant no.259537)The Young Scientists Fund of National Natural Science Foundation of China (Grant no.41206186) is acknowledged
文摘During years 1980/1981-2012/2013, inter-annual variations in sea ice and snow thickness in Kemi, in the northern coast of the Gulf of Bothnia, Baltic Sea, depended on the air temperature, snow fall, and rain. Inter-annual variations in the November--April mean air temperature, accumulated total precipitation, snow fall, and rain, as well as ice and snow thickness in Kemi and ice concentration in the Gulf of Bothnia correlated with inter-annual variations of the Pacific Decadal Oscillation （PDO）, Arctic Oscillation （AO）, North Atlantic Oscillation （NAO）, Scandinavian Pattern （SCA）, and Polar / Eurasian Pattern （PEU）. The strong role of PDO is a new finding. In general, the relationships with PDO were approximately equally strong as those with AO, but rain and sea ice concentration were better correlated with PDO. The correlations with PDO were, however, not persistent; for a study period since 1950 the correlations were much lower. During 1980/1981--2012/2013, also the Pacific / North American Pattern （PNA） and E1 Nino-Southern Oscillation （ENSO） had statistical connections with the conditions in the Gulf of Bothnia, revealed by analyzing their effects combined with those of PDO and AO. A reduced autumn sea ice area in the Arctic was related to increased rain and total precipitation in the following winter in Kemi. This correlation was significant for the Pan-Arctic sea ice area in September, October, and November, and for the November sea ice area in the Barents / Kara seas.
基金Supported by National Natural Science Foundation of China ( 41276199)Chinese Projects for Investigations and Assessments of the Arctic and Antarctic ( CHINARE 2012 - 2016 for 03-04 and 04-03)
文摘To study effects of variations in climate-marine environment in the Arctic Ocean on ecology,based on the actual and reestablished data by biomarkers of algae in sediment in 1997,1999,2003,2008,and 2010,the interannual and spatial variations of phytoplankton,zooplankton and chlorophyll a concentration in the Chukchi Sea and the Bering Sea as well as their relations to El Nino-Southern Oscillation( ENSO) and Arctic Oscillation( AO) were analyzed. The results show that there were spatial and temporal anomalies in the phytoplankton community structure reestablished by biomarkers of algae in the Chukchi Sea and the Bering Sea in 1999 and 2010. The total content of biomarkers( brassicasterol,dinosterol,C37 alkenones and chlesterol) in sediment collected in 2010 was far lower than that in 1999,but brassicasterol was dominant in the two years,that is,diatom was dominant,which was consistent with the actual structure and distribution of phytoplankton community in 1999 and 2010; there were great changes in the dominant species of plankton in the two seas in 1999 and 2010,which could be regarded as the ecological response of the North Pole under the background of global warming. Chlorophyll a concentration in the water of the Bering Sea was 0. 720 μg/dm^3 at 0 m and 0. 765μg/dm^3 at 10 m in 1997 and 0. 723 μg/dm^3 at 0 m and 0. 731 μg/dm^3 at 10 m in 2003,and the concentration was very close to each other,which was affected by El Ni1 o and the negative phase of AO. It was 0. 395 μg/dm^3 at 0 m in 1999 and 0. 399 μg/dm^3 at 0 m and 0. 357 μg/dm^3 at 10 m in 2008,which was influenced by La Ni1 a and the positive phase of AO. The phases and intensity of AO and ENSO had various effects on the quantity and dominant species of phytoplankton and zooplankton in the Chukchi Sea and the Bering Sea. During the period of AO with positive or negative phase and El Ni1o( in 1997 and 2003),their combination was favorable to the growth of phytoplankton and zooplankton,while the combination of negative phase of AO and La Nina( in 2010) had adverse effects on the growth of phytoplankton. The combination of AO with positive phase and strong La Nina( in 1999 and 2008) had small effects on phytoplankton community.
文摘The marine environment of North Sea and Baltic is one of the most heavily strained by numerous human activities. Simultaneously water and air temperatures increase more than elsewhere in Europe and globally, which cannot be explained with ＂global warming＂. The climatic change issue would be better understood if this extraordinary regional warming is sufficiently explained. The regional features are unique for in-depth studies due to different summer-winter conditions, shallowness of the seas, geographical structure, and main pathway for maritime weather patterns moving eastwards. The impact of sea activities on the seasonal sea water profile structure is contributing to stronger regional warming, change in growing season, and less severe sea ice conditions. The impact of the man, whether small or large, should be understood very soon and very thoroughly.
基金Supported by the National Key Basic Research Program of China under Grant No.2004CB418300National Natural Science Foundation of China under Grant No.40675042
文摘The flood and drought across the Yangtze and Huaihe River（Jianghuai） areas are frequent in summer, especially in June and July.Therefore,predicting the summer flood and drought in the Jianghuai region is always one of the key topics concerned by meteorologists in China.Previous studies focused more on the skin temperature anomalies in a local area,and paid less attention to the connections between the anomalies of land-sea thermal contrast in remote continents and the summer flood and drought in Jianghuai areas of China.By using the US NCEP/NCAR monthly mean reanalysis data and the rainfall data at 743 stations in China,based on the interdecadal variation characteristics of the flood and drought index（FDI） during 51 yr （1954-2004） in the Jianghuai region of China in summer,the North African areas have been selected as the key regions for the correlation analysis.The results show that the surface temperature anomalies in the key regions have good continuity in winter,and the winter North Atlantic Oscillation（NAO） is perhaps one of the important factors that bring about the continuity of the anomalies.By a singular value decomposition（SVD） analysis between the skin temperature in the previous winter in North Africa and the summer rainfall in the Jianghuai region,it is found that when the North African continent is colder（warmer） and its northwestern sea is warmer（colder）,the rainfall increases（decreases） in the Jianghuai region in summer generally.Further analysis finds that the anomaly of the surface temperature contrast between sea and land in North Africa has a good indication for the summer flood and drought in the Jianghuai areas of China.Therefore,a sea and land thermal contrast index（SLTCI） is defined to reflect the intensity of the large-scale land-sea thermal contrast.A positive correlation between the SLTCI in North Africa and the summer FDI in Jianghuai areas is identified,and it can well indicate the extreme flood and drought situations in the Jianghuai region of China.
基金Supported by the National Basic Research Program of China (Grant No. 2005CB- 422304)
文摘Using the alkenone paleotemperature index U k 37′, a high-resolution sea surface temperature (SST) record since 3600 a BP was reconstructed from the mud area in the north of the East China Sea. Combining with the grain size distribution curve of sensitive grain size group, which may reflect the East Asia Winter Monsoon activity, the palaeoenvironmental evolution cycle throughout the late Holocene in the area was obtained. The marine environment evolution during the last 3600 years displays a five-stage trend. (1) Temperature descending period from 0.85 cal. ka BP to present. The maximum temperature decrease amplitude is 2℃. The winter monsoon intensified and ‘Little Ice Age’ were recorded in this period. (2) Warming period from 1.90 to 0.85 cal. ka BP. The mean temperature increase amplitude is 0.8℃. The Sui-Tang warming period was recorded at about 0.85―1.35 cal. ka BP and a prominent cooling event was recorded at 1.4 cal. ka BP in this period. (3) Temperature descending period from 2.55 to 1.90 cal. ka BP. Temperature cooling amplitude is 0.9℃. This period is coincident with an integrated temperature circle recorded in the Antarctic ice core, with the temperature changes from a slow cooling stage to a rapid warming stage. (4) Temperature comparatively stable with a little ascending period from 3.2 to 2.55 cal. ka BP. Temperature warming amplitude is 0.3℃. This period is coincident with the temperature fluctuant ascending period recorded in Antarctic ice core. (5) Temperature comparatively stable with little descending period from 3.6 to 3.2 cal. ka BP. This period corresponds with the temperature fluctuant cooling period recorded in Antarctic ice core. Basically, those five periods were coincident with the Antarctic ice core record. During the global cooling stage, the SST change in the continental shelf sea can be adjusted simultaneously.
