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1The key theorem and the bounds on the rate of uniform convergence of learning theory on Sugeno measure space显示文摘Some properties of Sugeno measure are further discussed, which is a kind of typical nonadditive measure. The definitions and properties of gλ random variable and its distribution function, expected value, and variance are then presented. Markov ine- quality, Chebyshev’s inequality and the Khinchine’s Law of Large Numbers on Sugeno measure space are also proven. Furthermore, the concepts of empirical risk functional, expected risk functional and the strict consistency of ERM principle on Sugeno measure space are proposed. According to these properties and concepts, the key theorem of learning theory, the bounds on the rate of convergence of learning process and the rela- tions between these bounds and capacity of the set of functions on Sugeno measure space are given.HA Minghu LI Yan LI Jia TIAN Dazeng 2006Science in China(Series F)2006,49,3:16
2Distribution of δ^(18)O in surface snow along a transect from Zhongshan Station to Dome A,East Antarctica显示文摘Surface snow samples were collected during the 14th(1997/1998)and 24th(2007/2008)Chinese National Antarctica Research Expeditions along a transect from Zhongshan Station to Dome A.The stable oxygen isotope ratios of these samples were measured to investigate their relationships with temperature and geographical parameters(latitude,longitude,altitude and distance to the coast).The results reveal a strong positive correlation(R=0.945)betweenδ18O and mean annual temperature,with a gradient of 0.84‰°C-1,which is a little higher than that in Terre Adelie Land.Regression analyses also show that theδ18O of surface snow is strongly correlated with distance to the coast(R=0.942),latitude(R=0.942),and altitude(R=0.941).But no significant correlation was found betweenδ18O and longitude in study area.Altitude should be the most important factor influencing the δ18O distribution because of distinctive topography.Theδ18O-altitude and T-altitude gradients along this transect are determined to be-1.1‰/100 m and 1.31°C/100 m,respectively.DING MingHu XIAO CunDe JIN Bo REN JiaWen QIN DaHe SUN WeiZhen 2010Chinese Science Bulletin2010,55,24:7
3Surface mass balance and its climate significance from the coast to Dome A, East Antarctica显示文摘Based on stake measurements conducted along the Chinese Antarctic traverse since Jan.1999,we investigated the characteristics of surface mass balance(SMB)and related climate consequences from Zhongshan Station to Dome A,East Antarctica.Spatial analysis suggests that post-depositional processes have a great impact on surface morphology;thus,the representativeness of a single measurement should be discussed in conjunction with local climate features.The comparison among snow accumulation,ice sheet thickness,surface elevation,and ice velocity indicates that the bedrock topography has an indirect connection with the SMB patterns through controlling the surface topography and local climate.The observation reveals that the Lambert Glacier Basin has been experiencing increasing mass input(4.5%),whereas the inland area has experienced a 6%loss,since 2005.An overall estimation of the SMB along the route is 71.3±44.3 kg m?2 a?1,but the annual and regional variation is considerable.Tendency analysis shows that there are four sections with different SMB patterns as a result of three moisture sources and surface climatic discrepancy in the Antarctic inland.This study is the first to identify four SMB patterns from the coast to the Dome area and should provide a valuable contribution to modeling and remote sensing on a continental scale.DING MingHu XIAO CunDe LI ChuanJin QIN DaHe JIN Bo SHI GuiTao XIE AiHong CUI XiangBin 2015Science China Earth Sciences2015,58,10:7
4Image-denoising algorithm based on improved K-singular value decomposition and atom optimization显示文摘The traditional K-singular value decomposition(K-SVD)algorithm has poor imagedenoising performance under strong noise.An image-denoising algorithm is proposed based on improved K-SVD and dictionary atom optimization.First,a correlation coefficient-matching criterion is used to obtain a sparser representation of the image dictionary.The dictionary noise atom is detected according to structural complexity and noise intensity and removed to optimize the dictionary.Then,non-local regularity is incorporated into the denoising model to further improve image-denoising performance.Results of the simulated dictionary recovery problem and application on a transmission line dataset show that the proposed algorithm improves the smoothness of homogeneous regions while retaining details such as texture and edge.Rui Chen Dong Pu Ying Tong Minghu Wu 2022CAAI Transactions on Intelligence Technology2022,7,1:5
5Changes in the Proportion of Precipitation Occurring as Rain in Northern Canada during Spring–Summer from 1979–2015显示文摘Changes in the form of precipitation have a considerable impact on the Arctic cryosphere and ecological system by influencing the energy balance and surface runoff. In this study, station observations and ERA-Interim data were used to analyze changes in the rainfall to precipitation ratio(RPR) in northern Canada during the spring–summer season(March–July)from 1979–2015. Our results indicate that ERA-Interim describes the spring–summer variations and trends in temperature and the RPR well. Both the spring–summer mean temperature [0.4℃–1℃(10 yr)^(-1)] and the RPR [2%–6%(10 yr)^(-1)] increased significantly in the Canadian Arctic Archipelago from 1979–2015. Moreover, we suggest that, aside from the contribution of climate warming, the North Atlantic Oscillation is probably another key factor influencing temporal and spatial differences in the RPR over northern Canada.Wei HAN Cunde XIAO Tingfeng DOU Minghu DING 2018Advances in Atmospheric Sciences2018,35,9:5
6Dating a 109.9 m ice core from Dome A (East Antarctica) with volcanic records and a firn densification model显示文摘A 109.9 m ice core was extracted at a location about 300 m away from the Dome A summit(80°00′S,77°21″E) by the Chinese team of the International Trans-Antarctic Science Expedition(ITASE) during the 21st Chinese National Antarctica Research Expedition(CHINARE) in January 2005.Two independent methods were used for dating the ice core,volcanic event markers shown by prominent non-sea-salt sulfate(nss-SO42) and the Herron and Langway(H-L) firn densification model.Six promi-nent volcanic events(Agung 1963 AD,Tambora 1815 AD,Kuwae 1453 AD,Unknown 1259 AD,Taupo 186 AD and Pinatubo 1050 BC) were identified by comparison with other Antarctic ice cores.Based on the mean accumulation rates be-tween adjacent events,we estimate the age at the firn pore close-off depth(102 m) was 3516±100 a BP.This is the oldest close-off age ever reported from the Antarctic and the Greenland ice sheets.Calculations using the H-L model show that the age at the same depth is 3581±100 a BP.The two dating techniques differ by 65 years,or~1.8% of the record.We calculated the bottom age of the ice core as 4009±150 a BP using the volcanic dating method and 4115±150 a BP using the H-L model method.LI ChuanJin XIAO CunDe HOU ShuGui REN JiaWen DING MingHu GUO Rui 2012Science China Earth Sciences2012,55,8:5
7A 2680-year record of sea ice extent in the Ross Sea and the associated atmospheric circulation derived from the DT401 East Antarctic ice core显示文摘Long time series of Antarctic sea ice extent(SIE) are important for climate research and model forecasting. A historic ice extent in the Ross Sea in early austral winter was rebuilt through sea salt ions in the DT401 ice core in interior East Antarctica. El Ni?o-Southern Oscillation(ENSO) had a significant influence on the sea salt deposition in DT401 through its influence on the Ross Sea SIE and the transport of sea salt inland. Spectral analysis also supported the influence of ENSO with a significant 2–6 a periodicity band. In addition, statistically significant decadal(10 a) and pentadecadal(50–70 a) periodicities suggested the existence of a teleconnection from the Pacific decadal oscillation(PDO), which originated from sea surface temperature anomalies in the tropical Pacific Ocean. The first eigenvector of the empirical orthogonal function analysis(EOF1) showed lower values during the Medieval Warm Period(MWP), while higher values were found in the Little Ice Age(LIA). A higher frequency of ENSO events were found in the cold climatic stage. The post 1800 AD period was occupied by significant fluctuations of the EOF1, and PDO may be one of the influencing factors. The EOF1 values showed moderate fluctuations from 680 BC to 1000 AD, showing that the climate was relatively stable in this period.LI ChuanJin REN JiaWen XIAO CunDe HOU ShuGui DING MingHu QIN DaHe 2015Science China Earth Sciences2015,58,11:4
8Climate and meteorological processes of the East Antarctic ice sheet between Zhongshan and Dome-A显示文摘The 1228 km over-snow traverse route between the Chinese Zhongshan Station,on the coast of Prydz Bay,and Dome-A,at 4091 m elevation the highest point of the East Antarctic ice sheet,has been the focus of CHINARE surface meteorological and climate studies since 2002.A network of seven Automatic Weather Stations has been deployed along this section,including at Dome-A itself,and some of these have now provided nearly-hourly data for over a decade.Atmospheric boundary layer turbulence and radiation observations have been made over the near-coastal ice sheet inland of Zhongshan and surface turbulence measurements using an ultrasonic anemometer system have also been made in the deep interior of the ice sheet.Summer GPS radiosonde soundings of the atmospheric boundary layer have been made at Kunlun Station,near Dome-A.In this paper these observations are combined to provide a comprehensive overview of the meteorological regime of this region of the ice sheet,its climate variability,and as a reference for future study of climate change.This includes investigation of the variation of surface climate features with elevation and distance from the coast,the height and structure of the boundary layer over the ice sheet,and seasonal and regional changes in ice/snow-air interactions,including turbulent and radiative energy fluxes.The air temperature and snow temperature between the coastal Zhongshan and Dome-A on the inland plateau have not changed significantly in the past decade compared with the inter-annual variability.BIAN Lingen Ian Allison XIAO Cunde MA Yongfeng FU Liang DING Minghu 2016Advances in Polar Science2016,27,2:4
9Factors controlling the nitrate in the DT-401 ice core in eastern Antarctica显示文摘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.LI ChuanJin REN JiaWen QIN DaHe XIAO CunDe HOU ShuGui LI YuanSheng DING MingHu 2013Science China Earth Sciences2013,56,9:4
10Reconstruction of autumn sea ice extent changes since AD1289 in the Barents-Kara Sea, Arctic显示文摘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 AD1289–1993. 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 13 th century to the end of18 th century, the autumn B-K SIE was large, with large variations and a slightly expanding trend overall. This reflected significant multidecadal oscillations under the Little Ice Age(LIA) background. The B-K SIE began to decrease at the end of the18 th century, and a shrinking trend became significant during the second half of the 19 th century, which lasted into the 1930 s–1940 s. The 1930 s–1940 s was a period with a relatively low SIE in the B-K Sea, and the SIE had a short period of expansion from the 1940 s–1970 s. However, the B-K SIE has continuously and significantly shrank since the 1970 s. The reduction in the B-K SIE since the end of the 18 th century has been unprecedented in both duration and speed over the last 700 years. The B-K SIE has retreated significantly since the 1970 s, 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.Qi ZHANG Cunde XIAO Minghu DING Tingfeng DOU 2018Science China Earth Sciences2018,61,9:4
11Evolution of the microstructure and solute distribution of Sn-10wt% Bi alloys during electromagnetic field-assisted directional solidification显示文摘The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magnetic field(TSMF) and an external direct current(DC) have been investigated experimentally and numerically. The experimental results show that the solid-liquid interface will gradually become sloping with the increase of the forced flow velocity when the thermoelectric magnetic convection(TEMC)dominates the forced flow at solidification front. However, the interface will gradually become planar as the flow velocity further increases when the electromagnetic convection(EMC) dominates the forced flow. Moreover, when the flow velocity gradually increases, the primary dendrite spacing decreases from384 to 105 μm accordingly. The simulation results show that the solute distribution at the two sides of the sample can be significantly changed by the forced flow at solidification front. The rejected solute will be unidirectionally transported to one side of the sample along the TEMC(a low-velocity forced flow),thereby causing the formation of a sloping interface. However, the rejected solute will be returned back along the EMC(a higher-velocity force flow), which results in a planar interface. Furthermore, the solute content at the two sides of the sample under the forced flows at different velocities was measured. The results are in good agreement with the simulation results, which shows that the solute content difference between the two sides of the sample reaches the maximum when a 0.5 T TSMF is applied, while the solute content difference decreases to zero with a simultaneous application of a 0.5 T TSMF and a 1.6 × 10~5 A/m^2 external DC.Zhe Shen Minghu Peng Dongsheng Zhu Tianxiang Zheng Yunbo Zhong Weili Ren Chuanjun Li Weidong Xuan Zhongming Ren 2019Journal of Materials Science & Technology2019,35,4:4
12Structure of summer atmospheric boundary layer in the center of Arctic Ocean and its relation with sea ice extent change显示文摘The atmospheric vertical structure and changed characteristics of boundary layer parameters, as well as their relations with sea ice and temperature changes in the center of Arctic Ocean(80°–88°N) are presented by adopting GPS sounding data obtained by the 4th–6th Arctic expeditions of China and NCEP(National Centre for Environmental Prediction) reanalysis data. Obvious differences are observed regarding the tropopause, boundary layer height, temperature inversion, and vertical structure of wind speed and direction in the center Arctic Ocean in the summer of 2012, 2010, and 2014. These differences can be explained by the relations between temperature and changes in sea ice extent in September from 1979 to 2014. In September 2012, the Arctic sea ice extent decreased by 44% an with obvious warming process. In September 2010 and 2014, it decreased by 22.6% and 17% with an obvious cooling process, respectively. A comparison of the two processes shows that sea ice change has a significant influence on the structure of the atmospheric boundary layer. In the recent 30 years, the temperature changes of 1000 and 850 h Pa in the center of the Arctic Ocean have displayed an obvious warming trend and negative correlation with sea ice extent. These changes indicate that the continuous reduction of Arctic sea ice will continue the warming of the troposphere middle layer.BIAN LinGen DING MingHu LIN Xiang LU ChangGui GAO ZhiQiu 2016Science China Earth Sciences2016,59,5:4
13Arctic Climate Changes Based on Historical Simulations(1900-2013) with the CAMS-CSM显示文摘The Chinese Academy of Meteorological Sciences Climate System Model(CAMS-CSM) is a newly developed global climate model that will participate in the Coupled Model Intercomparison Project phase 6. Based on historical simulations(1900-2013), we evaluate the model performance in simulating the observed characteristics of the Arctic climate system, which includes air temperature, precipitation, the Arctic Oscillation(AO), ocean temperature/salinity,the Atlantic meridional overturning circulation(AMOC), snow cover, and sea ice. The model-data comparisons indicate that the CAMS-CSM reproduces spatial patterns of climatological mean air temperature over the Arctic(60°-90°N) and a rapid warming trend from 1979 to 2013. However, the warming trend is overestimated south of the Arctic Circle, implying a subdued Arctic amplification. The distribution of climatological precipitation in the Arctic is broadly captured in the model, whereas it shows limited skills in depicting the overall increasing trend. The AO can be reproduced by the CAMS-CSM in terms of reasonable patterns and variability. Regarding the ocean simulation, the model underestimates the AMOC and zonally averaged ocean temperatures and salinity above a depth of 500 m, and it fails to reproduce the observed increasing trend in the upper ocean heat content in the Arctic. The largescale distribution of the snow cover extent(SCE) in the Northern Hemisphere and the overall decreasing trend in the spring SCE are captured by the CAMS-CSM, while the biased magnitudes exist. Due to the underestimation of the AMOC and the poor quantification of air–sea interaction, the CAMS-CSM overestimates regional sea ice and underestimates the observed decreasing trend in Arctic sea–ice area in September. Overall, the CAMS-CSM reproduces a climatological distribution of the Arctic climate system and general trends from 1979 to 2013 compared with the observations, but it shows limited skills in modeling local trends and interannual variability.Ting WEI Jian LI Xinyao RONG Wenjie DONG Bingyi WU Minghu DING 2018Journal of Meteorological Research2018,32,6:4
146.5 wt%Si high silicon steel sheets prepared by composite electrodeposition in magnetic field显示文摘A new preparation method of near-net-shape 6.5 wt% Si high silicon steel sheets was proposed by combining composite electrodeposition(CED) and diffusion annealing under magnetic field. The obtained sheets were characterized by scanning electron microscopy, energy dispersive spectrometry, analytical balance and a silicon steel material measurement system. The results show that the surface morphology,the elemental distribution, the cathode current efficiency and the silicon content of coatings were obviously influenced by the micro and macro magnetohydrodynamics(MHD) flows under magnetic field.With the effect of magnetic field, the silicon particles content of coatings showed an increasing trend and the diffusion process showed that an approximately uniform 6.5 wt% silicon steel sheet has been successfully obtained. The magnetism measurement showed that the high silicon steel sheet has the lower iron loss, and the iron loss further decreased under magnetic field. The new method proposed in this article,which is more environmentally friendly and low energy consumption, is feasible to prepare high silicon steel sheets.Minghu Peng Yunbo Zhong Tianxiang Zheng Lijun Fan Junfeng Zhou Weili Ren Zhongming Ren 2018Journal of Materials Science & Technology2018,34,12:3
15Snowdrift effect on snow deposition:Insights from a comparison of a snow pit profile and meteorological observations in east Antarctica显示文摘A high-frequency and precise ultrasonic sounder was used to monitor precipitated/deposited and drift snow events over a 3-year period(17 January 2005 to 4 January 2008) at the Eagle automatic weather station site,inland Antarctica.Ion species and oxygen isotope ratios were also generated from a snow pit below the sensor.These accumulation and snowdrift events were used to examine the synchronism with seasonal variations of δ^(18)O and ion species,providing an opportunity to assess the snowdrift effect in typical Antarctic inland conditions.There were up to 1-year differences for this 3-year-long snow pit between the traditional dating method and ultrasonic records.This difference implies that in areas with low accumulation or high wind,the snowdrift effect can induce abnormal disturbances on snow deposition.The snowdrift effect should be seriously taken into account for high-resolution dating of ice cores and estimation of surface mass balance,especially when the morphology of most Antarctic inland areas is similar to that of the Eagle site.DING MingHu ZHANG Tong XIAO CunDe LI ChuanJin JIN Bo BIAN LinGen WANG ShuJie ZHANG DongQi QIN DaHe 2017Science China Earth Sciences2017,60,4:3
16The spatiotemporal patterns of sea ice in the Bohai Sea during the winter seasons of 2000–2016显示文摘In this study,sea ice thickness(SIT)and sea ice extent(SIE)in the Bohai Sea from 2000 to 2016 were investigated.A surface heat balance equation was applied to calculate SIT using ice surface temperatures estimated from the Moderate Resolution Imaging Spectroradiometer(MODIS)data with input from air temperature and wind speed from reanalyzing weather data.No trend was found in SIT during 2000–2016.The mean SIT and SIE during this period were 5.58±0.86 cm and 23×10^(3)±8×10^(3)km^(2),respectively.The largest SIT and SIE periods were observed during the second half of January and the first half of February,respectively.The Spearman correlation coefficient between mean ice thickness and average air temperature from 21 automatic weather stations around the Bohai Sea was–0.94(P<.005),and the coefficient between median ice extent and negative accumulated temperature was–0.503(P<.001).The rate of increase in air temperature around the Bohai Sea is 0.271℃per decade in winter for 1979–2016(P<.05),which is much lower than that in northern polar area(0.648℃per decade).This rate has not resulted in a decreasing trend in SIT and SIE for the past 16 years in the Bohai Sea.Lunxi Ouyang Fengming Hui Lixian Zhu Xiao Cheng Bin Cheng Mohammed Shokr Jiechen Zhao Minghu Ding Tao Zeng 2019International Journal of Digital Earth2019,12,8:3
17The design philosophy and bridge's technical innovation of Hong Kong- Zhuhai-Macao Bridge显示文摘This article introduces the project overview, construction goal and design philosophy of Hong Kong- Zhuhai-Macao Bridge. Based on large scale, factory production, standardization and assemble line, the innova- tive concept is taken as the general principle for design with the emphasis on description of the new material, new technology, new construction method and new equipment used in the design. The application of innovative technology has provided a solid foundation and favorable guarantee for project quality and design serviceMeng Fanchao Liu Minghu Wu Weisheng Zhang Gejun Zhang Liang 2014Engineering Sciences2014,12,3:3
18Surface energy balance on the Antarctic plateau as measured with an automatic weather station during 2014显示文摘AWS data during 2014 collected at PANDA-N station, on the East Antarctic Plateau, are analysed. Net Short Wave Radiation(QSWR), net Long Wave Radiation(QLWR), sensible(QH), latent(QL) and subsurface or ground(QG) heat fluxes are computed. Annual averages for QSWR, QLWR, QH, QL and QG of 19.65,-49.16, 26.40,-0.77 and 3.86 W·m-2 were derived based on an albedo value of 0.8. QSWR and QH are the major sources of heat gain to the surface and QLWR is the major component of heat loss from the surface. An i terative method is used to estimate surface temperature in this paper;surface temperature of snow/ice is gradually increased or decreased, thereby changing longwave radiation, sensible, latent and subsurface heat fluxes, so that the net energy balance becomes zero. Mass loss due to sublimation at PANDA-N station for 2014 is estimated to be 12.18 mm w.e.·a-1;and mass gain due to water vapour deposition is estimated to be 3.58 mm w.e.·a-1. Thus the net mass loss due to sublimation/deposition is 8.6 mm w.e.·a-1. This study computes surface energy fluxes using a model, instead of direct measurements. Also there are missing data especially for wind speed, though 2 m air temperature data is almost continuously available throughout the year. The uncertainties of albedo, wind speed and turbulent fluxes cause the most probable error in monthly values of QLWR, QH, QL, QG and surface temperature of about ±4%, ±20%, ±50%, ±11% and ±0.74 K respectively.DING Minghu Anubha AGRAWAL Petra HEIL YANG Diyi 2019Advances in Polar Science2019,30,2:3
19Spatial and temporal variability of marine-origin matter along a transect from Zhongshan Station to Dome A,Eastern Antarctica显示文摘The spatiotemporal distribution pattern of marine-origin matter on the Antarctica ice sheet was used to study variations in the source regions, transport mechanisms and postdepositional influences. We present data on sea salt ions, sulfur components and stable isotopes from surface and snow pit samples collected along the transect route from Zhongshan Station to Dome A during the austral summer in 2012–2013. A general decreasing trend in the accumulation, sea salt ions and sulfur components occurred with increasing distance from the coast and increasing elevation. However, different sources of the marine components, transport pathways and post-depositional influences were responsible for their different spatial distribution patterns. The marine ions in the coastal snow pit varied seasonally, with higher sea salt ion concentrations in the winter and lower concentrations in the summer; the opposite pattern was found for the sulfur compounds. The sea ice area surrounding Antarctica was the main source region for the deposited sea salt and the open sea water for the sulfur compounds. No significant trends in the marine-origin components were detected during the past 3 decades. Several periods of elevated deposition of sea salt ions were associated with lower temperatures(based on δD and δ18O) or intensified wind fields. In comparison to the sea salt ions, the sulfur concentrations exhibited the opposite distribution patterns and were associated with changes in the surrounding sea ice extent.Chuanjin Li Cunde Xiao Guitao Shi Minghu Ding Dahe Qin Jiawen Ren 2016Journal of Environmental Sciences2016,28,8:3
20Variations in stable hydrogen and oxygen isotopes in atmospheric water vapor in the marine boundary layer across a wide latitude range显示文摘The newly-developed cavity ring-down laser absorption spectroscopy analyzer with special calibration protocols has enabled the direct measurement of atmospheric vapor isotopes at high spatial and temporal resolution. This paper presents real-time hydrogen and oxygen stable isotope data for atmospheric water vapor above the sea surface, over a wide range of latitudes spanning from 38°N to 69°S. Our results showed relatively higher values of δ18O and δ2H in the subtropical regions than those in the tropical and high latitude regions, and also a notable decreasing trend in the Antarctic coastal region. By combining the hydrogen and oxygen isotope data with meteoric water line and backward trajectory model analysis,we explored the kinetic fractionation caused by subsiding air masses and related saturated vapor pressure in the subtropics, and the evaporation-driven kinetic fractionation in the Antarctic region. Simultaneous observations of meteorological and marine variables were used to interpret the isotopic composition characteristics and influential factors, indicating that d-excess is negatively correlated with humidity across a wide range of latitudes and weather conditions worldwide. Coincident with previous studies, d-excess is also positively correlated with sea surface temperature and air temperature(T air), with greater sensitivity to T air. Thus, atmospheric vapor isotopes measured with high accuracy and good spatial–temporal resolution could act as informative tracers for exploring the water cycle at different regional scales. Such monitoring efforts should be undertaken over a longer time period and in different regions of the world.Jingfeng Liu Cunde Xiao Minghu Ding Jiawen Ren 2014Journal of Environmental Sciences2014,26,11:3
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