[ Objective] The aim was to study the protein polymorphism in the blood of Tibetan Mastiff, and provide some theoretical basis for resource protection and reasonable development and utilization of Tibetan Mastiff vari...[ Objective] The aim was to study the protein polymorphism in the blood of Tibetan Mastiff, and provide some theoretical basis for resource protection and reasonable development and utilization of Tibetan Mastiff varieties. [ Method] A total of 103 blood samples were taken from four populations of Hequ Tibetan Mastiff, Qinhai Tibetan Mastiff, Tibetan Spaniel and native dogs of Qinghai. Seven blood protein Iocus(Tf, Po, Sα2, Hb, AIb, Pr and Amy)were investigated by using vertical polyacrylamide gel electrophoresis with discontinuous buffer system. Then the genetic variation during different populations was analyzed. [ Result] Genetic variations were observed in Tf, Sα2 and Po in four populations, others were not polymorphic. There were three alleles at the locus of Tf and Po, two alleles at the loci of Sα2. Effective number of alleles and Nei's average expected heterozygosity were 1. 532 4 and 0.230 3 relatively, all higher in Tibetan Mastiff than other populations. [ Conclusion] Protein locus in blood of Tibetan Mastiff existed in genetic variation.展开更多
To evaluate isotopic tracers at natural abundances by providing basic isotope data of the hydrological investigations and assessing the impacts of different factors on the water cycle, a total of 197 water samples wer...To evaluate isotopic tracers at natural abundances by providing basic isotope data of the hydrological investigations and assessing the impacts of different factors on the water cycle, a total of 197 water samples were collected from the Laohugou Glacial catchment in the Shule River basin northwestern China during the 2013 ablation seasons and analyzed their H- and O-isotope composition. The results showed that the isotopic composition of precipitation in the Qilianshan Station in the Laohugou Glacial catchment was remarkable variability. Correspondingly, a higher slope of δ180-δD diagram, with an average of 8.74, is obtained based on the precipitation samples collected on the Glacier No.la, mainly attributed to the lower temperature on the glacier surface. Because of percolation and elution, the bottom of the firn the isotopic composition at is nearly steady. The 6180 /altitude gradients for precipitation and melt water were -o.37%o/100 m and -o.34%o/100 m, respectively Exposed to the air and influenced by strong ablation and evaporation, the isotopic values and the 6180 vs 6D diagram of the glacial surface ice show no altitudinal effect, indicating that glacier ice has the similar origins with the firn. The variation of isotopic composition in the melt water, varying from -l0.7‰ to -16.9‰ (8180) and from -61.1%o to -122.1%o (6D) indicates the recharging of snowmelt and glacial ice melt water produced at different altitudes. With a mean value of -13.3‰ for 8180 and -89.7‰ for 8D, the isotopic composition of the stream water is much closer to the melt water, indicating that stream water is mainly recharged by the ablation water. Our results of the stable isotopic compositions in natural water in the Laohugou Glacial catchment indicate the fractionations and the smoothing fluctuations of the stable isotopes during evaporation, infiltration and mixture.展开更多
Changes in sea surface temperature (SST), seawater oxygen isotope (δ18Osw), and local salinity proxy (δ18Osw-ss ) in the past 155 ka were studied using a sediment core (MD06-3052) from the northern edge of t...Changes in sea surface temperature (SST), seawater oxygen isotope (δ18Osw), and local salinity proxy (δ18Osw-ss ) in the past 155 ka were studied using a sediment core (MD06-3052) from the northern edge of the western Pacific Warm Pool (WPWP), within the flow path of the bifurcation of the North Equatorial Current. Our records reveal a lead-lag relationship between paired Mg/Ca-SST and δ18O during Termination II and the last interglacial period. Similarity in SST between our site and the Antarctic temperature proxy and in CO2 profile showed a close connection between the WPWP and the Antarctic. Values of 818Osw exhibited very similar variations to those of mean ocean δ18Osw, owing to the past sea-level changes on glacial-interglacial timescale. Calculated values of δ18O reflect a more saline condition during high local summer insolation (SI) periods. Such correspondence between δ18O and local SI in the WPWP may reflect complex interaction between ENSO and monsoon, which was stimulated by changes in solar irradiance and their influence on the local hydrologic cycle. This then caused a striking reorganization of atmospheric circulation over the WPWP.展开更多
The distributions and correlations of chlorophyll-a(Chl-a),aerosol optical depth(AOD)and ice cover in the southeast Arctic Ocean-Greenland Sea(10°W–10°E,70°–80°N)between 2003 and 2009 were studie...The distributions and correlations of chlorophyll-a(Chl-a),aerosol optical depth(AOD)and ice cover in the southeast Arctic Ocean-Greenland Sea(10°W–10°E,70°–80°N)between 2003 and 2009 were studied using satellite data and statistical analyses.Regression analysis showed correlations between Chl-a and AOD,Chl-a and ice cover,and AOD and ice cover with different time lags.The time lag of Chl-a and AOD indicated their long-term equilibrium relationship.Peaks in AOD and Chl-a and generally occurred in May and July,respectively.Despite the time lag,the correlation between Chl-a and AOD in the study region was as high as 0.7.The peak gap between Chl-a and AOD shifted for about 6 weeks during 2003–2009.In the summer and autumn of 2009,Chl-a and AOD levels were much higher than during the other years,especially in the northern band of the study region(75°–80°N).The driving forces for this localized increase in phytoplankton biomass could be mainly attributed to the very high rate of ice melting in spring and early summer and the high wind speed in autumn,together with the increased deposition of aerosol throughout the year.The unusually high AOD in the spring of 2003 was mainly due to a massive fi re in Russia,which occurred in the fi rst half of the year.Over the 7 years of the study,the sea surface temperature generally decreased.This may have been due to the release of dimethylsulfi de into the air,excreted in large amounts from abundant phytoplankton biomass,and its subsequent reaction,form large amounts of aerosol,and resulting in regional cooling.展开更多
Sea ice thickness is one of the most important input parameters in the studies on sea ice disaster prevention and mitigation. It is also the most important content in remote sensing monitoring of sea ice. In this stud...Sea ice thickness is one of the most important input parameters in the studies on sea ice disaster prevention and mitigation. It is also the most important content in remote sensing monitoring of sea ice. In this study, a practical model of sea ice thickness(PMSIT) was proposed based on the Moderate Resolution Imaging Spectroradiometer(MODIS) data. In the proposed model, the MODIS data of the first band were used to estimate sea ice thickness and the difference between the second-band reflectance and the fifth-band reflectance in the MODIS data was calculated to obtain the difference attenuation index(DAI) of each pixel. The obtained DAI was used to estimate the integrated attenuation coefficient of the first band of the MODIS at the pixel level. Then the model was used to estimate sea ice thickness in the Bohai Sea with the MODIS data and then validated with the actual sea ice survey data. The validation results showed that the proposed model and corresponding parameterization scheme could largely avoid the estimation error of sea ice thickness caused by the spatial and temporal heterogeneity of sea ice extinction and allowed the error of 18.7% compared with the measured sea ice thickness.展开更多
The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in th...The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in the soils in 2005-2009 in the lowland of Kur-Araz. The investigations were fulfilled by using of geographical and stasionar methods. It is revealed that 333.6 thous, ha of the soils of the lowland of Kur-Araz have been exposed to erosion. 97.4 thousand ha of them have been exposed to rainstorm erosion, 127.1 thous, have been exposed to irrigative and 122.1 thous, ha to wind erosion. The most dangerous of them are considered irrigative erosion. Under the influence of erosion process in deposited over the length of furrow, deposits the changes happened in maintenance of humus and nutritions elements. In dependence on slope and water expenditure on 1 ha 2.23-14.86 t of soil are leached. As a result of out wash from 1 ha of soil 55.88-304.59 kg of humus, 4.06-20.80 kg of nitrogen, 4.57-26.55 of phosphorus and 57.40-372.99 of potassium are lost. The soil is exposed to degradation and as a result a process of desertification begins. On the basis of the quantitative an intensity of soil outwash the possible losses of dry matter including humus and main elements of nutrition of plants as a result of erosion, their deposit with the water way, are calculated, too.展开更多
Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors (i.e., latitude and altit...Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors (i.e., latitude and altitude) as the primary predictors and incorporates inverse distance weighting (IDW) technique. The method was applied to a high-resolution digital elevation model (DEM) to produce a grid map of multi-year mean δD values with lkm spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.展开更多
Studies on carbon isotopes of bulk carbonates from Longan and Baping sections of Lower Carboniferous in Guangxi of China show that the stable carbon isotope compositions in carbonate rocks of the isolated platform and...Studies on carbon isotopes of bulk carbonates from Longan and Baping sections of Lower Carboniferous in Guangxi of China show that the stable carbon isotope compositions in carbonate rocks of the isolated platform and deep slope facies were resistant to the influence of early meteoric diagenesis and late burial diagenesis. Three major positive carbon isotope excursions have been recognized in Lower Carboniferous in South China. The first major positive δ3C shift of 4.19‰ occurred in the middle part of Siphonodella isosticha-upper Siphonodella crenulata zone (Tournaisian); the second with an amplitude of 4.65‰ occurred near the Tournaisian/Visean boundary; and the third of 2.23‰ in the lower part of Gnathodus bollandensis zone. The three positive shifts of δ3C can be correlated with global carbon isotope excursions and are consistent with the fall in global sea level, indicating that abundant organic carbon burial, lowering of atmospheric CO2, and glaciation may have occurred during these time intervals.展开更多
For studying ice accretion on aircraft and helicopter airfoils,a modified model of the mass and heat transfer on icing surface was first proposed based on the classical Messinger model.Then an approach for predicting ...For studying ice accretion on aircraft and helicopter airfoils,a modified model of the mass and heat transfer on icing surface was first proposed based on the classical Messinger model.Then an approach for predicting ice accretion on multi-element airfoils was set up through introducing the interpolation calculation of airflow field around the multi-element airfoils.Consid-ering the equivalent thermal power from anti-ice system,a method of the prediction of ice accretion under anti-ice situation was proposed.In order to study the prediction of ice accretion on helicopter rotor,a numerical simulation method combining the computational fluid dynamics (CFD) technique with helicopter aerodynamics theory was set up.The agreement between the results of numerical simulation and the experimental data indicates that the model and methods proposed in this paper are feasible and effective,and that they can lay the foundation of the research on the dynamics in icing condition and design of anti/de-ice system.展开更多
Diurnal minor and trace elements in glacial outflow water draining the Qiyi Glacier and associated hydrological controls as well as the filtration effects on water chemistry were examined. Results show that major ions...Diurnal minor and trace elements in glacial outflow water draining the Qiyi Glacier and associated hydrological controls as well as the filtration effects on water chemistry were examined. Results show that major ions, Li, St, and Ba are exported pre- dominately as mobile monovalent or divalent ions and are controlled by hydrological variations over the diurnal cycle exhibit- ing an inverse concentration with discharge, suggesting that Li, Sr, and Ba can be used as tracers in subglacial hydrological investigations. Conversely, other elements (e.g. Fe, Al, and Cr) exhibit variations that are not strongly correlated with the dis- charge reflecting the physicochemical controls. The non-filtered operation appears not to strongly influence Sr and Ba, but has an effect on some elements such as Fe, Al, V, Ti, and Co, indicating that these changed elements are transported in particulate forms and thus their concentrations are highly dependent on particulate numbers in solutions. This implies that the immediate filtration after sampling is essential in hydrochemical studies at Alpine glacial basins due to subsequent mineral dissolution.展开更多
Using high-resolution ice core and tree ring proxies for sea ice extent (SIE), we reconstructed a robust time series of autumn SIE over the Barents-Kara (B-K) sector of the Arctic from AD 1289-1993. After intercom...Using high-resolution ice core and tree ring proxies for sea ice extent (SIE), we reconstructed a robust time series of autumn SIE over the Barents-Kara (B-K) sector of the Arctic from AD 1289-1993. After intercomparing the results and statistical parameters using the ordinary least squares regression (OLSR), the principle component regression (PCR) and the partial least squares regression (PLSR) methods, SIE time series were synthesized into a more robust series using the weighted average method, which used the explained variances as weights. The results showed that from the end of the 13th century to the end of 18th century, the autumn B-K SIE was large, with large variations and a slightly expanding trend overall. This reflected significant multideeadal oscillations under the Little Ice Age (LIA) background. The B-K SIE began to decrease at the end of the 18th century, and a shrinking trend became significant during the second half of the 19th century, which lasted into the 1930s- 1940s. The 1930s-1940s was a period with a relatively low SIE in the B-K Sea, and the SIE had a short period of expansion from the 1940s-1970s. However, the B-K SIE has continuously and significantly shrank since the 1970s. The reduction in the B-K SIE since the end of the 18th century has been unprecedented in both duration and speed over the last 700 years. The B-K SIE has retreated significantly since the 1970s, with a speed 6.18 times greater than the former mean retreating speed. The industrial revolution may be a dominant factor in this result. The Arctic SIE in recent years may be the lowest it has been over the last millennium.展开更多
Nitrate,an oxidized product of NO x preserved in the polar ice cores,has often been used to estimate past changes of the atmospheric nitrogen cycle.A 102.65 m ice core drilled at DT-401(79°01'S,77°00'...Nitrate,an oxidized product of NO x preserved in the polar ice cores,has often been used to estimate past changes of the atmospheric nitrogen cycle.A 102.65 m ice core drilled at DT-401(79°01'S,77°00'E) in 1999 provides an opportunity to investigate the possible influencing factors for the nitrate budget in the eastern Antarctica.We studied the relationship between the δ18O(representing the temperature),accumulation rate,volcanic deposition and the astronomical factors(such as the solar activities,supernovae,etc.),and the nitrate variation along the whole duration(2680-year) of the ice core.Prominent impacts of the accumulation rate acting on the nitrate flux rather than the concentration were detected.However,no significant correlation was found between the δ18O and the nitrate deposition characteristics(concentration and the flux variations).Volcanic deposition can significantly affect the deposition of nitrate with a decreasing trend accompanied by the nss-SO42(volcanic signal) peak values.Impacts of the solar activities on the nitrate deposition can be detected at this site,and three prominent periodicities(16.6,24.0 and 102.0 yr) were found for the nitrate concentration variations.Six climatic events(Dalton Minimum,Maunder Minimum,Sporer Minimum,Wolf Minimum,Oort Minimum and Medieval Maximum) during the past 1150 years were observed with lower nitrate values for the foregoing five events and higher value for the last one.展开更多
基金Supported by Foundation of Gansu Technology Committee (GKC-97-27-5)Youth Foundation of Tianshui Normal University (X4-25)~~
文摘[ Objective] The aim was to study the protein polymorphism in the blood of Tibetan Mastiff, and provide some theoretical basis for resource protection and reasonable development and utilization of Tibetan Mastiff varieties. [ Method] A total of 103 blood samples were taken from four populations of Hequ Tibetan Mastiff, Qinhai Tibetan Mastiff, Tibetan Spaniel and native dogs of Qinghai. Seven blood protein Iocus(Tf, Po, Sα2, Hb, AIb, Pr and Amy)were investigated by using vertical polyacrylamide gel electrophoresis with discontinuous buffer system. Then the genetic variation during different populations was analyzed. [ Result] Genetic variations were observed in Tf, Sα2 and Po in four populations, others were not polymorphic. There were three alleles at the locus of Tf and Po, two alleles at the loci of Sα2. Effective number of alleles and Nei's average expected heterozygosity were 1. 532 4 and 0.230 3 relatively, all higher in Tibetan Mastiff than other populations. [ Conclusion] Protein locus in blood of Tibetan Mastiff existed in genetic variation.
基金the projects of National Major Scientific Research Project (2013CBA01806)National Natural Science Foundation of China (Grant Nos. 41271085,41130641)open fund project of State Key Laboratory of Cryospheric Science (SKLCS-OP2013-05)
文摘To evaluate isotopic tracers at natural abundances by providing basic isotope data of the hydrological investigations and assessing the impacts of different factors on the water cycle, a total of 197 water samples were collected from the Laohugou Glacial catchment in the Shule River basin northwestern China during the 2013 ablation seasons and analyzed their H- and O-isotope composition. The results showed that the isotopic composition of precipitation in the Qilianshan Station in the Laohugou Glacial catchment was remarkable variability. Correspondingly, a higher slope of δ180-δD diagram, with an average of 8.74, is obtained based on the precipitation samples collected on the Glacier No.la, mainly attributed to the lower temperature on the glacier surface. Because of percolation and elution, the bottom of the firn the isotopic composition at is nearly steady. The 6180 /altitude gradients for precipitation and melt water were -o.37%o/100 m and -o.34%o/100 m, respectively Exposed to the air and influenced by strong ablation and evaporation, the isotopic values and the 6180 vs 6D diagram of the glacial surface ice show no altitudinal effect, indicating that glacier ice has the similar origins with the firn. The variation of isotopic composition in the melt water, varying from -l0.7‰ to -16.9‰ (8180) and from -61.1%o to -122.1%o (6D) indicates the recharging of snowmelt and glacial ice melt water produced at different altitudes. With a mean value of -13.3‰ for 8180 and -89.7‰ for 8D, the isotopic composition of the stream water is much closer to the melt water, indicating that stream water is mainly recharged by the ablation water. Our results of the stable isotopic compositions in natural water in the Laohugou Glacial catchment indicate the fractionations and the smoothing fluctuations of the stable isotopes during evaporation, infiltration and mixture.
基金Supported by the National Natural Science Foundation of China(Nos.41230959,41076030,41106042,40906038,41206044)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11030104)the Project of Global Change and Air-Sea Interaction
文摘Changes in sea surface temperature (SST), seawater oxygen isotope (δ18Osw), and local salinity proxy (δ18Osw-ss ) in the past 155 ka were studied using a sediment core (MD06-3052) from the northern edge of the western Pacific Warm Pool (WPWP), within the flow path of the bifurcation of the North Equatorial Current. Our records reveal a lead-lag relationship between paired Mg/Ca-SST and δ18O during Termination II and the last interglacial period. Similarity in SST between our site and the Antarctic temperature proxy and in CO2 profile showed a close connection between the WPWP and the Antarctic. Values of 818Osw exhibited very similar variations to those of mean ocean δ18Osw, owing to the past sea-level changes on glacial-interglacial timescale. Calculated values of δ18O reflect a more saline condition during high local summer insolation (SI) periods. Such correspondence between δ18O and local SI in the WPWP may reflect complex interaction between ENSO and monsoon, which was stimulated by changes in solar irradiance and their influence on the local hydrologic cycle. This then caused a striking reorganization of atmospheric circulation over the WPWP.
基金Supported by the National Natural Science Foundation of China(No.41276097)
文摘The distributions and correlations of chlorophyll-a(Chl-a),aerosol optical depth(AOD)and ice cover in the southeast Arctic Ocean-Greenland Sea(10°W–10°E,70°–80°N)between 2003 and 2009 were studied using satellite data and statistical analyses.Regression analysis showed correlations between Chl-a and AOD,Chl-a and ice cover,and AOD and ice cover with different time lags.The time lag of Chl-a and AOD indicated their long-term equilibrium relationship.Peaks in AOD and Chl-a and generally occurred in May and July,respectively.Despite the time lag,the correlation between Chl-a and AOD in the study region was as high as 0.7.The peak gap between Chl-a and AOD shifted for about 6 weeks during 2003–2009.In the summer and autumn of 2009,Chl-a and AOD levels were much higher than during the other years,especially in the northern band of the study region(75°–80°N).The driving forces for this localized increase in phytoplankton biomass could be mainly attributed to the very high rate of ice melting in spring and early summer and the high wind speed in autumn,together with the increased deposition of aerosol throughout the year.The unusually high AOD in the spring of 2003 was mainly due to a massive fi re in Russia,which occurred in the fi rst half of the year.Over the 7 years of the study,the sea surface temperature generally decreased.This may have been due to the release of dimethylsulfi de into the air,excreted in large amounts from abundant phytoplankton biomass,and its subsequent reaction,form large amounts of aerosol,and resulting in regional cooling.
基金Under the auspices of the National Natural Science Foundation of China(No.41306091)Public Science and Technology Research Funds Projects of Ocean(No.201505019-2)
文摘Sea ice thickness is one of the most important input parameters in the studies on sea ice disaster prevention and mitigation. It is also the most important content in remote sensing monitoring of sea ice. In this study, a practical model of sea ice thickness(PMSIT) was proposed based on the Moderate Resolution Imaging Spectroradiometer(MODIS) data. In the proposed model, the MODIS data of the first band were used to estimate sea ice thickness and the difference between the second-band reflectance and the fifth-band reflectance in the MODIS data was calculated to obtain the difference attenuation index(DAI) of each pixel. The obtained DAI was used to estimate the integrated attenuation coefficient of the first band of the MODIS at the pixel level. Then the model was used to estimate sea ice thickness in the Bohai Sea with the MODIS data and then validated with the actual sea ice survey data. The validation results showed that the proposed model and corresponding parameterization scheme could largely avoid the estimation error of sea ice thickness caused by the spatial and temporal heterogeneity of sea ice extinction and allowed the error of 18.7% compared with the measured sea ice thickness.
文摘The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in the soils in 2005-2009 in the lowland of Kur-Araz. The investigations were fulfilled by using of geographical and stasionar methods. It is revealed that 333.6 thous, ha of the soils of the lowland of Kur-Araz have been exposed to erosion. 97.4 thousand ha of them have been exposed to rainstorm erosion, 127.1 thous, have been exposed to irrigative and 122.1 thous, ha to wind erosion. The most dangerous of them are considered irrigative erosion. Under the influence of erosion process in deposited over the length of furrow, deposits the changes happened in maintenance of humus and nutritions elements. In dependence on slope and water expenditure on 1 ha 2.23-14.86 t of soil are leached. As a result of out wash from 1 ha of soil 55.88-304.59 kg of humus, 4.06-20.80 kg of nitrogen, 4.57-26.55 of phosphorus and 57.40-372.99 of potassium are lost. The soil is exposed to degradation and as a result a process of desertification begins. On the basis of the quantitative an intensity of soil outwash the possible losses of dry matter including humus and main elements of nutrition of plants as a result of erosion, their deposit with the water way, are calculated, too.
基金Under the auspices of National Natural Science Foundation of China (No. 40825017, 40576001)100 Talents Project of Chinese Academy of SciencesNational Key Technologies R&D Program of China (No. 2006BAB18B01)
文摘Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors (i.e., latitude and altitude) as the primary predictors and incorporates inverse distance weighting (IDW) technique. The method was applied to a high-resolution digital elevation model (DEM) to produce a grid map of multi-year mean δD values with lkm spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.
基金supported by MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Grant No. G0800-06-ZS-319)
文摘Studies on carbon isotopes of bulk carbonates from Longan and Baping sections of Lower Carboniferous in Guangxi of China show that the stable carbon isotope compositions in carbonate rocks of the isolated platform and deep slope facies were resistant to the influence of early meteoric diagenesis and late burial diagenesis. Three major positive carbon isotope excursions have been recognized in Lower Carboniferous in South China. The first major positive δ3C shift of 4.19‰ occurred in the middle part of Siphonodella isosticha-upper Siphonodella crenulata zone (Tournaisian); the second with an amplitude of 4.65‰ occurred near the Tournaisian/Visean boundary; and the third of 2.23‰ in the lower part of Gnathodus bollandensis zone. The three positive shifts of δ3C can be correlated with global carbon isotope excursions and are consistent with the fall in global sea level, indicating that abundant organic carbon burial, lowering of atmospheric CO2, and glaciation may have occurred during these time intervals.
基金supported by the Aeronautical Science Foundation of China (Grant No. 2009ZA51007)
文摘For studying ice accretion on aircraft and helicopter airfoils,a modified model of the mass and heat transfer on icing surface was first proposed based on the classical Messinger model.Then an approach for predicting ice accretion on multi-element airfoils was set up through introducing the interpolation calculation of airflow field around the multi-element airfoils.Consid-ering the equivalent thermal power from anti-ice system,a method of the prediction of ice accretion under anti-ice situation was proposed.In order to study the prediction of ice accretion on helicopter rotor,a numerical simulation method combining the computational fluid dynamics (CFD) technique with helicopter aerodynamics theory was set up.The agreement between the results of numerical simulation and the experimental data indicates that the model and methods proposed in this paper are feasible and effective,and that they can lay the foundation of the research on the dynamics in icing condition and design of anti/de-ice system.
基金supportedby Key Program of National Natural Science Foundation of China (Grant No. 41030527)Hundred Talents Program of the Chinese Academy of Sciences (Grant No. 0827611002)+4 种基金West Light Program for Talent Cultiration of Chinese Academy of Sciences (CAS), Open Foundation of SKLCS, CAS (Grant No. SKLCS09-04)China Postdoctoral Science Foundation (Grant No. 20110490062)Indenendent Program of SKLCS,CAS (Grant No. SKLCS-ZZ-2012-02-01)National Natural Science Foundation of China (Grant Nos. 40930526 and 40771046)Foundation for Excellent Youth Scholars of CAREERI, CAS
文摘Diurnal minor and trace elements in glacial outflow water draining the Qiyi Glacier and associated hydrological controls as well as the filtration effects on water chemistry were examined. Results show that major ions, Li, St, and Ba are exported pre- dominately as mobile monovalent or divalent ions and are controlled by hydrological variations over the diurnal cycle exhibit- ing an inverse concentration with discharge, suggesting that Li, Sr, and Ba can be used as tracers in subglacial hydrological investigations. Conversely, other elements (e.g. Fe, Al, and Cr) exhibit variations that are not strongly correlated with the dis- charge reflecting the physicochemical controls. The non-filtered operation appears not to strongly influence Sr and Ba, but has an effect on some elements such as Fe, Al, V, Ti, and Co, indicating that these changed elements are transported in particulate forms and thus their concentrations are highly dependent on particulate numbers in solutions. This implies that the immediate filtration after sampling is essential in hydrochemical studies at Alpine glacial basins due to subsequent mineral dissolution.
基金supported by the National Natural Science Foundation of China (Grant No. 41425003)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA19070103)+1 种基金the Basic Research Project of Chinese Academy of Meteorological Sciences-Base Construction of Polar Atmospheric Sciences for Field Observationthe Scientific Research Foundation of the Key Laboratory of Cryospheric Sciences (Grant No. SKLCS-OP-2016-03)
文摘Using high-resolution ice core and tree ring proxies for sea ice extent (SIE), we reconstructed a robust time series of autumn SIE over the Barents-Kara (B-K) sector of the Arctic from AD 1289-1993. After intercomparing the results and statistical parameters using the ordinary least squares regression (OLSR), the principle component regression (PCR) and the partial least squares regression (PLSR) methods, SIE time series were synthesized into a more robust series using the weighted average method, which used the explained variances as weights. The results showed that from the end of the 13th century to the end of 18th century, the autumn B-K SIE was large, with large variations and a slightly expanding trend overall. This reflected significant multideeadal oscillations under the Little Ice Age (LIA) background. The B-K SIE began to decrease at the end of the 18th century, and a shrinking trend became significant during the second half of the 19th century, which lasted into the 1930s- 1940s. The 1930s-1940s was a period with a relatively low SIE in the B-K Sea, and the SIE had a short period of expansion from the 1940s-1970s. However, the B-K SIE has continuously and significantly shrank since the 1970s. The reduction in the B-K SIE since the end of the 18th century has been unprecedented in both duration and speed over the last 700 years. The B-K SIE has retreated significantly since the 1970s, with a speed 6.18 times greater than the former mean retreating speed. The industrial revolution may be a dominant factor in this result. The Arctic SIE in recent years may be the lowest it has been over the last millennium.
基金supported by the Foundation for Excellent Youth Scholars of CAREERI,CASthe National Natural Science Foundation of China(Grant Nos.40776002,40825017,41171052)+2 种基金the Hundred Talent Project of Chinese Academy of Sciencesthe Polar Scientific Explore Organizing Committee Foundation (Grant Nos.20080202&0852H71001)State Oceanic Administration of People's Republic of China Project on Climate in Polar Regions(Grant Nos.CHINARE2012-04-04 and CHINARE2012-02-02)
文摘Nitrate,an oxidized product of NO x preserved in the polar ice cores,has often been used to estimate past changes of the atmospheric nitrogen cycle.A 102.65 m ice core drilled at DT-401(79°01'S,77°00'E) in 1999 provides an opportunity to investigate the possible influencing factors for the nitrate budget in the eastern Antarctica.We studied the relationship between the δ18O(representing the temperature),accumulation rate,volcanic deposition and the astronomical factors(such as the solar activities,supernovae,etc.),and the nitrate variation along the whole duration(2680-year) of the ice core.Prominent impacts of the accumulation rate acting on the nitrate flux rather than the concentration were detected.However,no significant correlation was found between the δ18O and the nitrate deposition characteristics(concentration and the flux variations).Volcanic deposition can significantly affect the deposition of nitrate with a decreasing trend accompanied by the nss-SO42(volcanic signal) peak values.Impacts of the solar activities on the nitrate deposition can be detected at this site,and three prominent periodicities(16.6,24.0 and 102.0 yr) were found for the nitrate concentration variations.Six climatic events(Dalton Minimum,Maunder Minimum,Sporer Minimum,Wolf Minimum,Oort Minimum and Medieval Maximum) during the past 1150 years were observed with lower nitrate values for the foregoing five events and higher value for the last one.