Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still l...Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices.展开更多
Sawuer region is located in west Junggar,Jimunai County of Altay district and Hefeng County of Tacheng district,Xinjiang.The region is along the north margin of Kazakstan-Junggar plate.The intrusions(mainly acid)are w...Sawuer region is located in west Junggar,Jimunai County of Altay district and Hefeng County of Tacheng district,Xinjiang.The region is along the north margin of Kazakstan-Junggar plate.The intrusions(mainly acid)are widespread.Qiaqihai and Kuoyitasi intrusions are important in the region,with the characteristics of A-type granite.Further investigations indicate that they belong to A2-type granite that formed in extension tectonic setting of post collision.The REE chon-drite-normalized patterns of the intrusions show LREE enrichment and theδEu values are lower.The Nd,Sr,Pb isotope compositions of the intrusions indicate a mantle source,while the lowδ18O values resulted from the isotope exchange between intrusion and meteoric water.According to SHRIMP U-Pb age analysis results,the crystallization age of Qiaqihai intrusion is 290.7±9.3 Ma(1σ),and that of Kuoyitasi intrusion is 297.9±4.6 Ma(1σ),corresponding to the beginning of early Permian.The A2-type granites indicate that the region was in the extension period of the post-collisional stage at the beginning of early Permian in the Sawuer region.The A-type granites in the Sawuer region in west Junggar discovered from this work is analogous to the A-type granites found in east Junggar of the Ulungur alkali granites belt.The confirmation of post-collisional A-type granites of early Permian in the Sawuer region provides new evidence for the regional vertical continental crust growth in early Per-mian.The former proposed Ulungur alkali granites belt can extend from east Ulungur through west Ulungur and to Zhaisang in Kazakstan westwards.展开更多
基金supported by the National Research and Development Program of China(Nos.2020YFA0608203 and 2016YFC1402003)the FengYun Application Pioneering Project of China Meteorological Administration(No.FYAPP2021)+1 种基金the National Natural Science Foundation of China(No.42001362)the NUIST-Reading Research Institute Pump-Priming Application.
文摘Sea ice has important effect on the marine ecosystem and people living in the surrounding regions in winter.However,the understanding on changes of sea ice in the Bohai and northern Huanghai Sea(BNHS),China is still limited.Based on the images from Visible and InfraRed Radiometer(VIRR)onboard Chinese second generation polar-orbit meteorological series satellites FY-3A/B/C,the sea ice areas in the BNHS were extracted from December 2008 to March 2019,the spatio-temporal distribution charac-teristics of sea ice and the relationship between sea ice area and climatic factors were analyzed,then a preliminary sea ice forecast model based on the climatic factors was developed.The results showed that sea ice area in the BNHS in each December was relatively small and rather high sea ice occurrence probability appeared in the offshore areas in Liaodong Bay and northern Huanghai Sea.The sea ice area in January or February each year was the largest,and sea ice occurred in most of areas in Liaodong Bay and northern Huanghai Sea with rather high probability and in some areas in Bohai Bay and Laizhou Bay with relatively high probability.How-ever,the sea ice area in each March was the smallest,and sea ice was even melted completely occasionally,hence with relatively low occurrence probability in Liaodong Bay.As for the inter-annual variability of sea ice in the BNHS during the research period,the sea ice area was largest in winter 2010/11 and smallest in winter 2014/15,and annual sea ice area presented a decreasing trend.The at-mospheric temperature,western Pacific subtropical high(WPSH),Asia polar vortex(APV),Asian monsoon circulation(AMC)and Eurasian monsoon circulation(EMC)were very important climatic factors for sea ice formation and they had significant correlations with sea ice area.Therefore,a preliminary sea ice forecast model was constructed by using eight climatic factors including western Pacific subtropical high area index(WPSHAI),western Pacific subtropical high intensity index(WPSHII),western Pacific subtro-pical high northern boundary position index(WPSHNBPI),Asia polar vortex area index(APVAI),Asian zonal circulation index(AZCI),Asian meridional circulation index(AMCI),Eurasian zonal circulation index(EZCI)and mean minimum atmospheric tem-perature(MMAT).The model was confirmed to have a robust forecast effect by using F-test and validated sample data.The results are useful for monitoring sea ice with remote sensed data and forecasting sea ice conditions by climatic indices.
基金sponsored by the Na-tional Key Basic Science Research project of China(Grant No.2001CB409800)the Anhi Provincial Excellent Youth Science and Technology Foundation(Grant No.04045063).
文摘Sawuer region is located in west Junggar,Jimunai County of Altay district and Hefeng County of Tacheng district,Xinjiang.The region is along the north margin of Kazakstan-Junggar plate.The intrusions(mainly acid)are widespread.Qiaqihai and Kuoyitasi intrusions are important in the region,with the characteristics of A-type granite.Further investigations indicate that they belong to A2-type granite that formed in extension tectonic setting of post collision.The REE chon-drite-normalized patterns of the intrusions show LREE enrichment and theδEu values are lower.The Nd,Sr,Pb isotope compositions of the intrusions indicate a mantle source,while the lowδ18O values resulted from the isotope exchange between intrusion and meteoric water.According to SHRIMP U-Pb age analysis results,the crystallization age of Qiaqihai intrusion is 290.7±9.3 Ma(1σ),and that of Kuoyitasi intrusion is 297.9±4.6 Ma(1σ),corresponding to the beginning of early Permian.The A2-type granites indicate that the region was in the extension period of the post-collisional stage at the beginning of early Permian in the Sawuer region.The A-type granites in the Sawuer region in west Junggar discovered from this work is analogous to the A-type granites found in east Junggar of the Ulungur alkali granites belt.The confirmation of post-collisional A-type granites of early Permian in the Sawuer region provides new evidence for the regional vertical continental crust growth in early Per-mian.The former proposed Ulungur alkali granites belt can extend from east Ulungur through west Ulungur and to Zhaisang in Kazakstan westwards.
