This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asi...This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia. Related to the dipole mode, with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring, the East Asian summer subtropical rainy belt tends to move northward. The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June. The wave train enhances the northern East Asian low, which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward. This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.展开更多
Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amou...Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.展开更多
OWTs （offshore wind turbines） are currently considered as a reliable source of renewable energy. OWT support structures account for 20%-25% of the capital cost for offshore wind installations. Pre-feasibility studie...OWTs （offshore wind turbines） are currently considered as a reliable source of renewable energy. OWT support structures account for 20%-25% of the capital cost for offshore wind installations. Pre-feasibility studies involving estimation of preliminary dimensions of the wind turbine structure need to be performed for initial costing to arrive at the commercial viability of the project. The main objective of the paper is to obtain preliminary configuration for commercial viability and approximate sizing of the foundation pile. Design equations and nomograms are proposed for quick preliminary design of monopile founded wind turbines located offshore of Gujarat. Parametric studies are carried-out on various configurations of a hollow monopile by varying water depths and properties of sand. A nonlinear static analysis of substructure is performed considering aerodynamic forces and hydrodynamic forces for various structural and soil parameters. The sub-structure design of wind turbine is based on API （American petroleum institute） standards. A simplified design methodology for monopile support structure under extreme loading condition is presented based on multivariable linear regression analysis. The input variables for the regression analysis are hydrodynamic data, angle of internal friction of sand, and the output variables are length and outer diameter of monopile. This simplified methodology is applicable in pre-studies of wind power parks.展开更多
In this study,the reversal of monthly East Asian winter air temperature(EAWT) in 2020/21 and its predictability were investigated.The reversal of monthly EAWT in 2020/21 was characterized by colder temperatures in ear...In this study,the reversal of monthly East Asian winter air temperature(EAWT) in 2020/21 and its predictability were investigated.The reversal of monthly EAWT in 2020/21 was characterized by colder temperatures in early winter(December 2020 to mid-January 2021) and warmer temperatures in late winter(mid-January to February 2021).Results show that the reversal in the intensity of the Siberian high(SH) also occurred between early and late winter in 2020/21.In early winter,as the Barents-Laptev sea ice in the previous September(i.e., in2020) reached a minimum for the period 1981-2020,the SH was strengthaned via a reduction of the meridional gradient between the Arctic and East Asia.In late winter,as a sudden stratospheric warming occurred on 5 January 2021,the stratospheric polar vortex weakened,with the weakest center shifting to North America in January.Subsequently,the negative Arctic Oscillation-like structure shifted towards North America in the middle and lower troposphere,which weakened the SH in late winter.Furthermore,the predictability of the reversal in EAWT in 2020/21 was validated based on monthly and daily predictions from NCEP-CFSv2(National Centers for Environment Prediction-Climate Forecast System,version 2).The results showed that the model was unable to reproduce the monthly reversal of EAWT.However,it was able to forecast the reversal date(18 January 2021)of EAWT at lead times of 1-20 days on the daily scale.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 41375086 and 41775062]the National Natural Science Foundation of China[grant number 41630530]+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(CAS)supported by the Youth Innovation Promotion Association of CAS
文摘This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia. Related to the dipole mode, with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring, the East Asian summer subtropical rainy belt tends to move northward. The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June. The wave train enhances the northern East Asian low, which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward. This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.
基金Projects(40672040,40472042 and 40603008) supported by the National Natural Science Foundation of ChinaProject(2001CB409802) supported by the Major State Basic Research Development Program of China+1 种基金 Project(2005038237) supported by the Postdoctoral Science Foundation of China Project supported by the Opening Foundation of State Key Laboratory of Continental Dynamics,Northwest University
文摘Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.
文摘OWTs （offshore wind turbines） are currently considered as a reliable source of renewable energy. OWT support structures account for 20%-25% of the capital cost for offshore wind installations. Pre-feasibility studies involving estimation of preliminary dimensions of the wind turbine structure need to be performed for initial costing to arrive at the commercial viability of the project. The main objective of the paper is to obtain preliminary configuration for commercial viability and approximate sizing of the foundation pile. Design equations and nomograms are proposed for quick preliminary design of monopile founded wind turbines located offshore of Gujarat. Parametric studies are carried-out on various configurations of a hollow monopile by varying water depths and properties of sand. A nonlinear static analysis of substructure is performed considering aerodynamic forces and hydrodynamic forces for various structural and soil parameters. The sub-structure design of wind turbine is based on API （American petroleum institute） standards. A simplified design methodology for monopile support structure under extreme loading condition is presented based on multivariable linear regression analysis. The input variables for the regression analysis are hydrodynamic data, angle of internal friction of sand, and the output variables are length and outer diameter of monopile. This simplified methodology is applicable in pre-studies of wind power parks.
基金jointly supported by the National Natural Science Foundation of China [grant numbers 42088101 and 41730964]the Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) [grant number 311021001]。
文摘In this study,the reversal of monthly East Asian winter air temperature(EAWT) in 2020/21 and its predictability were investigated.The reversal of monthly EAWT in 2020/21 was characterized by colder temperatures in early winter(December 2020 to mid-January 2021) and warmer temperatures in late winter(mid-January to February 2021).Results show that the reversal in the intensity of the Siberian high(SH) also occurred between early and late winter in 2020/21.In early winter,as the Barents-Laptev sea ice in the previous September(i.e., in2020) reached a minimum for the period 1981-2020,the SH was strengthaned via a reduction of the meridional gradient between the Arctic and East Asia.In late winter,as a sudden stratospheric warming occurred on 5 January 2021,the stratospheric polar vortex weakened,with the weakest center shifting to North America in January.Subsequently,the negative Arctic Oscillation-like structure shifted towards North America in the middle and lower troposphere,which weakened the SH in late winter.Furthermore,the predictability of the reversal in EAWT in 2020/21 was validated based on monthly and daily predictions from NCEP-CFSv2(National Centers for Environment Prediction-Climate Forecast System,version 2).The results showed that the model was unable to reproduce the monthly reversal of EAWT.However,it was able to forecast the reversal date(18 January 2021)of EAWT at lead times of 1-20 days on the daily scale.
