Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ...Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ablation season is analyzed in detail. Results show that the annual maximum ice thickness in 2005 occurred in later November, and then ice started to reek, and the ablation duration was 62 days; sea water under the ice became warmer synchronously; corresponding to the warming sea ice temperature, a ＂relative cold mid-layer＂ appeared in sea ice; the fast ice marginal line recoiled back to the shore observably, and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006. In addition, based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005, the ice thickness distribution paten in the marginal ice zone have been described ： sea ice thickness increased, but the diversity of floe ice thick-ness decreased from open water to fast ice zone distinctly.展开更多
Available data show that the of fossil plants testified that the Antarctica was a rather warm or even hot and humid region covered with forest from Devonian to Cretaceous [periods. Furthermore, even Antarctic coasts s...Available data show that the of fossil plants testified that the Antarctica was a rather warm or even hot and humid region covered with forest from Devonian to Cretaceous [periods. Furthermore, even Antarctic coasts stilll kept in a warm and humid condition until early Tertiary of 37 Ma ago. It therefore can be considered that the Antarctica was not situated at its present position, but in tropic or temperate zone before the Tertiary.Antarctic ice sheet has begun to appear in the Pligocene of 26Ma ago. It was very much earlier than the glaciations in everywhere of the world. For the reasons a most important event was the separating of Antarctic Peninsula from South America in 35 Ma ago. Drake Passage therefore occurred and Antarctic circulation appeared, and then Antarctic continent became an isolated cold land.Glacial changes have happened on the Antarctic ice sheet from late Tertiary to Quaternary periods. However, it has been confirmed that the Antarctic ice sheet has a great extension during the latest Pleistocene glaciation of 25000-l0000a B. P. About 18000a ago, the Antarctic ice sheet was 450-1000 m thicker and much larger than that at present. By that time the ice sheet grounded on the conticental shelves. Sea level might be 100-150 m or more lower than present sea level. Sca ice covered areas in winter and in summer were 10 and 2 times respectively than that today.It was much warmer in middle Holocene (7500-5000 a B. P.) than today in Antarctic region. By that time, a large amount of ice was melt away, which, on one hand.[caused a rapid rising of sea level, transgression immediately occurred; on the other hand, as continental load decreased due to the melting of ice sheet, the isostatic uplifting consequently followed and the marine terraces formed along Antarctic coasts in middle Holocene, Now the glacio-isostatic uplift is still going on. For a total uplift of 10-25 m since 6000 a B. P. the mean rate of 1.5-4mm/a is estimated in different places of Antarctic coasts.Antarctic ice sheet (including ice shelves) has been retreating recently, Meanwhile, the inland snow accumulation has been increasing in the past decades of years, both of them are corresponding to the rising of annual mean temperature since 1910 A. D.展开更多
It is a common sense that enterprise is the principal of endogenous innovation, but why many firms do not innovate actively？ What kind of difficulty will enterprises suffer in endogenous innovation？ What can the gov...It is a common sense that enterprise is the principal of endogenous innovation, but why many firms do not innovate actively？ What kind of difficulty will enterprises suffer in endogenous innovation？ What can the government do for the endogenous innovation？ These questions are very crucial to realize endogenous innovation. This paper tries to answer the questions mentioned above from the perspective of technology evolution. The industrial environment of emerging technology is emphasized for analyzing the endogenous innovation in Chinese enterprises. The process of endogenous innovation in NanShanBridge Co. Ltd （NSBIC）, which is an IC design firm, is analyzed as a case. From the case study, we can answer the questions above in certain extent, give some suggestions to the enterprises as a later-comer, and present some advice to government.展开更多
In Northeast China, permafrost advanced and retreated several times under the influences of fluctuating paleo-climatesand paleo-environments since the Late Pleistocene. During the last 60 years, many new data were obt...In Northeast China, permafrost advanced and retreated several times under the influences of fluctuating paleo-climatesand paleo-environments since the Late Pleistocene. During the last 60 years, many new data were obtained and studies wereconducted on the evolution of permafrost in Northeast China, but so far no systematic summary and review have been made.Based on sedimentary sequences, remains of past permafrost, paleo-flora and -fauna records, and dating data, permafrostevolution since the Late Pleistocene has been analyzed and reconstructed in this paper. Paleo-temperatures reconstructedfrom the remains of past permafrost and those from paleo-flora and -fauna are compared, and thus the southern limitof permafrost （SLP） in each climate period is inferred by the relationship of the permafrost distribution and the meanannual air/ground temperatures （MAAT/MAGT）. Thus, the evolutionary history of permafrost is here divided into fivestages： （1） the Late Pleistocene （Last Glaciation, or LG） （65 to 10–8.5 ka）, the Last Glaciation Maximum （LGM, 21–13 ka）in particular, the coldest period in the latest history with a cooling of about 6~10 °C, characterized by extensive occurrencesof glaciation, flourishing Mammathas-Coelodonta Faunal Complex （MCFC）, widespread aeolian deposits, and significantsea level lowering, and permafrost greatly expanded southwards almost to the coastal plains （37°N–41°N）; （2） the HoloceneMegathermal Period （HMP, 8.5–7.0 to 4.0–3.0 ka）, 3~5 °C warmer than today, permafrost retreated to about 52°N; （3） theLate Holocene Cold Period （Neoglaciation） （4.0–3.0 to 1.0–0.5 ka）, a cooling of 1~3 °C, some earlier thawed permafrost wasrefrozen or attached, and the SLP invaded southwards to 46°N; （4） the Little Ice Age （LIA, 500 to 100–150 a）, the latestcold period with significant permafrost expansion; and （5） climate warming since the last century, during which NortheastChina has undergone extensive permafrost degradation. The frequent and substantial expansions and retreats of permafrosthave greatly impacted cold-region environments in Northeast China. North of the SLP during the HMP, or in the presentcontinuous permafrost zone, the existing permafrost was largely formed during the LG and was later overlapped by thepermafrost formed in the Neoglaciation. To the south, it was formed in the Neoglaciation. However, many aspects ofpermafrost evolution still await further investigations, such as data integration, numerical reconstruction, and merging ofChinese permafrost history with those of bordering regions as well as collaboration with related disciplines. Of these, studies on the evolution and degradation of permafrost during the past 150 years and its hydrological, ecological, and environmentalimpacts should be prioritized.展开更多
The ice conditions in the Bohai Sea and the northern Huanghai Sea greatly change from year to year with winter climate. Ice only covers below 15% of the the waters during the wannest win-ter, while it covers more than...The ice conditions in the Bohai Sea and the northern Huanghai Sea greatly change from year to year with winter climate. Ice only covers below 15% of the the waters during the wannest win-ter, while it covers more than 80% during the coldest winter. Ice observation and data acquisition are outlined in the paper. The ice-covered area, the position of ice edge and the ice grades give indication of the ice conditions. The local climate of the waters can be expressed by using the air temperature of the stations of Dalian and Yingkou. The variation of the ice condition indexes with the monthly mean air temperature at Dalian from 1952 to 2000 is shown, as well. The local climate and ice conditions in the waters are affected by many factors,such as, evolution of the general atmospheric circulation and the solar activity. The delayed correlation between the ice conditions and lots of the affecting factors is analysed in the paper. The ice conditions are continuously mild since the 1990s, that is relative to the tendency of the global warming. The ice condition variation of the Bohai Sea is related to the El Nino event and the sunspot period. The seasonal evolution of the ice conditions is also described in the paper.展开更多
This study examined the mass change of the Antarctic ice sheet(AIS) based on ICESat and CryoSat-2 observations. We estimated the AIS exhibited mass losses of-101±15 Gt·aduring the ICESat period(Sept–Nov 200...This study examined the mass change of the Antarctic ice sheet(AIS) based on ICESat and CryoSat-2 observations. We estimated the AIS exhibited mass losses of-101±15 Gt·aduring the ICESat period(Sept–Nov 2003 to Sept–Oct 2009) and-186±55 Gt·aduring the CryoSat-2 period(Jan 2011 to Dec 2015). Mass losses occurred mainly in the sectors of the Amundsen and Bellingshausen seas. Benefitting from the 30-d subcycle of CryoSat-2, we obtained monthly estimates of mass evolution. Considerable annual variations were observed in the mass evolution sequences and the climatological monthly mass evolution. Seasonal mass evolutions in the sectors of the Bellingshausen and Amundsen seas were found most representative of the annual variation. The geographical distribution characteristics of interannual AIS mass evolution were revealed by the annual average mass evolution sequences. During Jan 2011 to Dec 2015, the ice sheets in the sectors of the Bellingshausen and Amundsen seas, and the Totten Glacier, experienced increasingly rapid areal mass loss. An area of mass gain with a moderate rate of increase was found between Dronning Maud Land and Enderby Land. Rapid mass accumulation has occurred in a limited area of the Kamb Ice Stream.展开更多
基金supported by the National Natural Science Foundation of China under contract No.40676001 No.40233032,the National Key Technology R&D Program No.2006BAB18B03.
文摘Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ablation season is analyzed in detail. Results show that the annual maximum ice thickness in 2005 occurred in later November, and then ice started to reek, and the ablation duration was 62 days; sea water under the ice became warmer synchronously; corresponding to the warming sea ice temperature, a ＂relative cold mid-layer＂ appeared in sea ice; the fast ice marginal line recoiled back to the shore observably, and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006. In addition, based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005, the ice thickness distribution paten in the marginal ice zone have been described ： sea ice thickness increased, but the diversity of floe ice thick-ness decreased from open water to fast ice zone distinctly.
文摘Available data show that the of fossil plants testified that the Antarctica was a rather warm or even hot and humid region covered with forest from Devonian to Cretaceous [periods. Furthermore, even Antarctic coasts stilll kept in a warm and humid condition until early Tertiary of 37 Ma ago. It therefore can be considered that the Antarctica was not situated at its present position, but in tropic or temperate zone before the Tertiary.Antarctic ice sheet has begun to appear in the Pligocene of 26Ma ago. It was very much earlier than the glaciations in everywhere of the world. For the reasons a most important event was the separating of Antarctic Peninsula from South America in 35 Ma ago. Drake Passage therefore occurred and Antarctic circulation appeared, and then Antarctic continent became an isolated cold land.Glacial changes have happened on the Antarctic ice sheet from late Tertiary to Quaternary periods. However, it has been confirmed that the Antarctic ice sheet has a great extension during the latest Pleistocene glaciation of 25000-l0000a B. P. About 18000a ago, the Antarctic ice sheet was 450-1000 m thicker and much larger than that at present. By that time the ice sheet grounded on the conticental shelves. Sea level might be 100-150 m or more lower than present sea level. Sca ice covered areas in winter and in summer were 10 and 2 times respectively than that today.It was much warmer in middle Holocene (7500-5000 a B. P.) than today in Antarctic region. By that time, a large amount of ice was melt away, which, on one hand.[caused a rapid rising of sea level, transgression immediately occurred; on the other hand, as continental load decreased due to the melting of ice sheet, the isostatic uplifting consequently followed and the marine terraces formed along Antarctic coasts in middle Holocene, Now the glacio-isostatic uplift is still going on. For a total uplift of 10-25 m since 6000 a B. P. the mean rate of 1.5-4mm/a is estimated in different places of Antarctic coasts.Antarctic ice sheet (including ice shelves) has been retreating recently, Meanwhile, the inland snow accumulation has been increasing in the past decades of years, both of them are corresponding to the rising of annual mean temperature since 1910 A. D.
文摘It is a common sense that enterprise is the principal of endogenous innovation, but why many firms do not innovate actively？ What kind of difficulty will enterprises suffer in endogenous innovation？ What can the government do for the endogenous innovation？ These questions are very crucial to realize endogenous innovation. This paper tries to answer the questions mentioned above from the perspective of technology evolution. The industrial environment of emerging technology is emphasized for analyzing the endogenous innovation in Chinese enterprises. The process of endogenous innovation in NanShanBridge Co. Ltd （NSBIC）, which is an IC design firm, is analyzed as a case. From the case study, we can answer the questions above in certain extent, give some suggestions to the enterprises as a later-comer, and present some advice to government.
基金supported by the Subproject No. XDA05120302 (Permafrost Extent in China during the Last Glaciation Maximum and Megathermal)Strategic Pilot Science and Technology Program of the Chinese Academy of Sciences (Identification of Carbon Budgets for Adaptation to Changing Climate and the Associated Issues) (Grant No. XDA05000000)the auspices of the International Permafrost Association (IPA) Action Group on "Last Permafrost Maximum and Minimum (LPMM) on the Eurasian Continent"
文摘In Northeast China, permafrost advanced and retreated several times under the influences of fluctuating paleo-climatesand paleo-environments since the Late Pleistocene. During the last 60 years, many new data were obtained and studies wereconducted on the evolution of permafrost in Northeast China, but so far no systematic summary and review have been made.Based on sedimentary sequences, remains of past permafrost, paleo-flora and -fauna records, and dating data, permafrostevolution since the Late Pleistocene has been analyzed and reconstructed in this paper. Paleo-temperatures reconstructedfrom the remains of past permafrost and those from paleo-flora and -fauna are compared, and thus the southern limitof permafrost （SLP） in each climate period is inferred by the relationship of the permafrost distribution and the meanannual air/ground temperatures （MAAT/MAGT）. Thus, the evolutionary history of permafrost is here divided into fivestages： （1） the Late Pleistocene （Last Glaciation, or LG） （65 to 10–8.5 ka）, the Last Glaciation Maximum （LGM, 21–13 ka）in particular, the coldest period in the latest history with a cooling of about 6~10 °C, characterized by extensive occurrencesof glaciation, flourishing Mammathas-Coelodonta Faunal Complex （MCFC）, widespread aeolian deposits, and significantsea level lowering, and permafrost greatly expanded southwards almost to the coastal plains （37°N–41°N）; （2） the HoloceneMegathermal Period （HMP, 8.5–7.0 to 4.0–3.0 ka）, 3~5 °C warmer than today, permafrost retreated to about 52°N; （3） theLate Holocene Cold Period （Neoglaciation） （4.0–3.0 to 1.0–0.5 ka）, a cooling of 1~3 °C, some earlier thawed permafrost wasrefrozen or attached, and the SLP invaded southwards to 46°N; （4） the Little Ice Age （LIA, 500 to 100–150 a）, the latestcold period with significant permafrost expansion; and （5） climate warming since the last century, during which NortheastChina has undergone extensive permafrost degradation. The frequent and substantial expansions and retreats of permafrosthave greatly impacted cold-region environments in Northeast China. North of the SLP during the HMP, or in the presentcontinuous permafrost zone, the existing permafrost was largely formed during the LG and was later overlapped by thepermafrost formed in the Neoglaciation. To the south, it was formed in the Neoglaciation. However, many aspects ofpermafrost evolution still await further investigations, such as data integration, numerical reconstruction, and merging ofChinese permafrost history with those of bordering regions as well as collaboration with related disciplines. Of these, studies on the evolution and degradation of permafrost during the past 150 years and its hydrological, ecological, and environmentalimpacts should be prioritized.
基金This work was supported by the National Natural Science Foundation of China under contract Nos 49976007 and 59739170Universi
文摘The ice conditions in the Bohai Sea and the northern Huanghai Sea greatly change from year to year with winter climate. Ice only covers below 15% of the the waters during the wannest win-ter, while it covers more than 80% during the coldest winter. Ice observation and data acquisition are outlined in the paper. The ice-covered area, the position of ice edge and the ice grades give indication of the ice conditions. The local climate of the waters can be expressed by using the air temperature of the stations of Dalian and Yingkou. The variation of the ice condition indexes with the monthly mean air temperature at Dalian from 1952 to 2000 is shown, as well. The local climate and ice conditions in the waters are affected by many factors,such as, evolution of the general atmospheric circulation and the solar activity. The delayed correlation between the ice conditions and lots of the affecting factors is analysed in the paper. The ice conditions are continuously mild since the 1990s, that is relative to the tendency of the global warming. The ice condition variation of the Bohai Sea is related to the El Nino event and the sunspot period. The seasonal evolution of the ice conditions is also described in the paper.
基金funded by the Key Program of National Natural Science Foundation of China (Grant no. 41531069)the Chinese Polar Environment Comprehensive Investigation and Assessment Programs (Grant no. CHINARE2016-02-02)
文摘This study examined the mass change of the Antarctic ice sheet(AIS) based on ICESat and CryoSat-2 observations. We estimated the AIS exhibited mass losses of-101±15 Gt·aduring the ICESat period(Sept–Nov 2003 to Sept–Oct 2009) and-186±55 Gt·aduring the CryoSat-2 period(Jan 2011 to Dec 2015). Mass losses occurred mainly in the sectors of the Amundsen and Bellingshausen seas. Benefitting from the 30-d subcycle of CryoSat-2, we obtained monthly estimates of mass evolution. Considerable annual variations were observed in the mass evolution sequences and the climatological monthly mass evolution. Seasonal mass evolutions in the sectors of the Bellingshausen and Amundsen seas were found most representative of the annual variation. The geographical distribution characteristics of interannual AIS mass evolution were revealed by the annual average mass evolution sequences. During Jan 2011 to Dec 2015, the ice sheets in the sectors of the Bellingshausen and Amundsen seas, and the Totten Glacier, experienced increasingly rapid areal mass loss. An area of mass gain with a moderate rate of increase was found between Dronning Maud Land and Enderby Land. Rapid mass accumulation has occurred in a limited area of the Kamb Ice Stream.
