The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding ...The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding the sea ice concentration in the wind wave module;however,they simply suppose that the wind cannot penetrate the ice layer and ignore the possibility of wind forcing waves below the ice cover.To improve the simulation performance of wind wave modules in the marginal ice zone(MIZ),this study proposes a parameterization scheme by directly including the sea ice thickness.Instead of scaling the wind input with the fraction of open water,this new scheme allows partial wind input in ice-covered areas based on the ice thickness.Compared with observations in the Barents Sea in 2016,the new scheme appears to improve the modeled waves in the high-frequency band.Sensitivity experiments with and without wind wave modules show that wind waves can play an important role in areas with low sea ice concentration in the MIZ.展开更多
A robust phenomenon termed the Arctic Amplification(AA)refers to the stronger warming taking place over the Arctic compared to the global mean.The AA can be confirmed through observations and reproduced in climate mod...A robust phenomenon termed the Arctic Amplification(AA)refers to the stronger warming taking place over the Arctic compared to the global mean.The AA can be confirmed through observations and reproduced in climate model simulations and shows significant seasonality and inter-model spread.This study focuses on the influence of surface type on the seasonality of AA and its inter-model spread by dividing the Arctic region into four surface types:ice-covered,ice-retreat,ice-free,and land.The magnitude and inter-model spread of Arctic surface warming are calculated from the difference between the abrupt-4×CO_(2)and pre-industrial experiments of 17 CMIP6 models.The change of effective thermal inertia(ETI)in response to the quadrupling of CO_(2) forcing is the leading mechanism for the seasonal energy transfer mechanism,which acts to store heat temporarily in summer and then release it in winter.The ETI change is strongest over the ice-retreat region,which is also responsible for the strongest AA among the four surface types.The lack of ETI change explains the nearly uniform warming pattern across seasons over the ice-free(ocean)region.Compared to other regions,the ice-covered region shows the maximum inter-model spread in JFM,resulting from a stronger inter-model spread in the oceanic heat storage term.However,the weaker upward surface turbulent sensible and latent heat fluxes tend to suppress the inter-model spread.The relatively small inter-model spread during summer is caused by the cancellation of the inter-model spread in ice-albedo feedback with that in the oceanic heat storage term.展开更多
It is crucial to appropriately determine turbulent fluxes in numerical models.Using data collected in East Antarctica from 8 April to 26 November 2016,this study evaluates parameterization schemes for turbulent fluxes...It is crucial to appropriately determine turbulent fluxes in numerical models.Using data collected in East Antarctica from 8 April to 26 November 2016,this study evaluates parameterization schemes for turbulent fluxes over the landfast seaice surface in five numerical models.The Community Noah Land Surface Model with Multi-Parameterizations Options(Noah_mp)best replicates the turbulent momentum flux,while the Beijing Climate System Model(BCC_CSM)produces the optimum sensible and latent heat fluxes.In particular,two critical issues of parameterization schemes,stability functions and roughness lengths,are investigated.Sensitivity tests indicate that roughness lengths play a decisive role in model performance.Based on the observed turbulent fluxes,roughness lengths over the landfast sea-ice surface are calculated.The results,which can provide a basis for setting up model parameters,reveal that the dynamic roughness length(z0m)increases with the increase of frictional velocity(u*)when u*≤0.4 m s^(−1) and fluctuates around 10^(−3 )m when u*>0.4 m s^(−1);thermal roughness length(z0t)is linearly related to the temperature gradient between air and sea-ice surface(ΔT)with a relation of lg(z0t)=−0.29ΔT−3.86;and the mean water vapor roughness length(z0q)in the specific humidity gradient(Δq)range ofΔq≤−0.6 g kg^(−1) is 10^(−6) m,3.5 times smaller than that in the range ofΔq˃−0.6 g kg^(−1).展开更多
This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)p...This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)product is chosen as the validation reference data.Results show that most models can adequately reproduce the climatological mean,seasonal cycle,and long-term trend of Arctic Ocean SIT during 1979-2014,but significant inter-model spread exists.Differences in simulated SIT patterns among the CMIP6 models may be related to model resolution and sea ice model components.By comparing the climatological mean and trend for SIT among all models,the Arctic SIT change in different seas during 1979-2014 is evaluated.Under the scenario of historical radiative forcing,the Arctic SIT will probably exponentially decay at-18%(10 yr)-1 and plausibly reach its minimum(equilibrium)of 0.47 m since the 2070s.展开更多
Maize growth and development are regulated by light quality,intensity and photoperiod.Cryptochromes are blue/ultraviolet-A light receptors involved in stem elongation,shade avoidance,and photoperiodic flowering.To inv...Maize growth and development are regulated by light quality,intensity and photoperiod.Cryptochromes are blue/ultraviolet-A light receptors involved in stem elongation,shade avoidance,and photoperiodic flowering.To investigate the function of cryptochrome 1(CRY1) in maize,where it is encoded by Zm CRY1,we obtained two Zm CRY1a genes(Zm CRY1a1 and Zm CRY1a2),both of which share the highest similarity with other gramineous plants,in particular rice CRY1a by phylogenetic analysis.In Arabidopsis,overexpression of Zm CRY1a genes promoted seedling de-etiolation under blue and white light,resulting in dwarfing of mature plants.In seedlings of the maize inbred line Zong 31(Zm CRY1aOE),overexpression of Zm CRY1a genes caused a reduction in the mesocotyl and first leaf sheath lengths due to down-regulation of genes influencing cell elongation.In mature transgenic maize plants,plant height,ear height,and internode length decreased in response to overexpression of Zm CRY1a genes.Expression of Zm CRY1a were insensitive to low blue light(LBL)-induced shade avoidance syndrome(SAS) in Arabidopsis and maize.This prompted us to investigate the regulatory role of the gibberellin and auxin metabolic pathways in the response of Zm CRY1a genes to LBL treatment.We confirmed a link between Zm CRY1a expression and hormonal influence on the growth and development of maize under LBL-induced SAS.These results reveal that Zm CRY1a has a relatively conservative function in regulating maize photomorphogenesis and may guide new strategies for breeding high density-tolerant maize cultivars.展开更多
Sea ice,one of the most dominant barriers to Arctic shipping,has decreased dramatically over the past four decades.Arctic maritime transport is hereupon growing in recent years.To produce a long-term assessment of tra...Sea ice,one of the most dominant barriers to Arctic shipping,has decreased dramatically over the past four decades.Arctic maritime transport is hereupon growing in recent years.To produce a long-term assessment of trans-Arctic accessibility,we systematically revisit the daily Arctic navigability with a view to the combined effects of sea ice thickness and concentration throughout the period 1979−2020.The general trends of Navigable Windows(NW)in the Northeast Passage show that the number of navigable days is steadily growing and reached 89±16 days for Open Water(OW)ships and 163±19 days for Polar Class 6(PC6)ships in the 2010s,despite high interannual and interdecadal variability in the NWs.More consecutive NWs have emerged annually for both OW ships and PC6 ships since 2005 because of the faster sea ice retreat.Since the 1980s,the number of simulated Arctic routes has continuously increased,and optimal navigability exists in these years of record-low sea ice extent(e.g.,2012 and 2020).Summertime navigability in the East Siberian and Laptev Seas,on the other hand,varies dramatically due to changing sea ice conditions.This systematic assessment of Arctic navigability provides a reference for better projecting the future trans-Arctic shipping routes.展开更多
The Arctic climate system has changed rapidly during recent decades with a two-four times faster warming rate than the global average subject to the uncertainties of analysis datasets and approaches.These changes have...The Arctic climate system has changed rapidly during recent decades with a two-four times faster warming rate than the global average subject to the uncertainties of analysis datasets and approaches.These changes have apparently resulted in broader and sizeable impacts within the Arctic,in the low/mid-latitudes,and globally.The importance of these changes and impacts makes the Arctic stand out within the global climate systems,drawing great attention and interests from the climate research community,the general public,and the government sector.One of the persistent,leading-edge topics in climate stud-ies during recent decades has therefore been to improve understanding of the underlying driving mechanisms,evaluate socioe-conomic and ecological impacts,and enhance the ability of the prediction and projections of Arctic climate changes.展开更多
The Arctic sea-ice extent has shown a declining trend over the past 30 years. Ice coverage reached historic minima in 2007 and again in 2012. This trend has recently been assessed to be unique over at least the last 1...The Arctic sea-ice extent has shown a declining trend over the past 30 years. Ice coverage reached historic minima in 2007 and again in 2012. This trend has recently been assessed to be unique over at least the last 1450 years. In the summer of 2010, a very low sea-ice concentration(SIC) appeared at high Arctic latitudes—even lower than that of surrounding pack ice at lower latitudes. This striking low ice concentration—referred to here as a record low ice concentration in the central Arctic(CARLIC)—is unique in our analysis period of 2003–15, and has not been previously reported in the literature. The CARLIC was not the result of ice melt, because sea ice was still quite thick based on in-situ ice thickness measurements.Instead, divergent ice drift appears to have been responsible for the CARLIC. A high correlation between SIC and wind stress curl suggests that the sea ice drift during the summer of 2010 responded strongly to the regional wind forcing. The drift trajectories of ice buoys exhibited a transpolar drift in the Atlantic sector and an eastward drift in the Pacific sector,which appeared to benefit the CARLIC in 2010. Under these conditions, more solar energy can penetrate into the open water,increasing melt through increased heat flux to the ocean. We speculate that this divergence of sea ice could occur more often in the coming decades, and impact on hemispheric SIC and feed back to the climate.展开更多
Annual observations of first-year ice(FYI) and second-year ice(SYI) near Zhongshan Station, East Antarctica,were conducted for the first time from December 2011 to December 2012. Melt ponds appeared from early Decembe...Annual observations of first-year ice(FYI) and second-year ice(SYI) near Zhongshan Station, East Antarctica,were conducted for the first time from December 2011 to December 2012. Melt ponds appeared from early December 2011. Landfast ice partly broke in late January, 2012 after a strong cyclone. Open water was refrozen to form new ice cover in mid-February, and then FYI and SYI co-existed in March with a growth rate of 0.8 cm/d for FYI and a melting rate of 2.7 cm/d for SYI. This difference was due to the oceanic heat flux and the thickness of ice,with weaker heat flux through thicker ice. From May onward, FYI and SYI showed a similar growth by 0.5 cm/d.Their maximum thickness reached 160.5 cm and 167.0 cm, respectively, in late October. Drillings showed variations of FYI thickness to be generally less than 1.0 cm, but variations were up to 33.0 cm for SYI in March,suggesting that the SYI bottom was particularly uneven. Snow distribution was strongly affected by wind and surface roughness, leading to large thickness differences in the different sites. Snow and ice thickness in Nella Fjord had a similar "east thicker, west thinner" spatial distribution. Easterly prevailing wind and local topography led to this snow pattern. Superimposed ice induced by snow cover melting in summer thickened multi-year ice,causing it to be thicker than the snow-free SYI. The estimated monthly oceanic heat flux was ~30.0 W/m2 in March–May, reducing to ~10.0 W/m2 during July–October, and increasing to ~15.0 W/m2 in November. The seasonal change and mean value of 15.6 W/m2 was similar to the findings of previous research. The results can be used to further our understanding of landfast ice for climate change study and Chinese Antarctic Expedition services.展开更多
Antarctic polynyas play an important role in regional atmosphere?ice?ocean interactions and are considered to help generate the global deep ocean conveyer belt.Polynyas therefore have a potential impact on the Earth’...Antarctic polynyas play an important role in regional atmosphere?ice?ocean interactions and are considered to help generate the global deep ocean conveyer belt.Polynyas therefore have a potential impact on the Earth’s climate in terms of the production of sea ice and high-salinity shelf water.In this study,we investigated the relationship between the area of the Terra Nova Bay polynya and the air temperature as well as the eastward and northward wind based on the ERA5 and ERAInterim reanalysis datasets and observations from automatic weather stations during the polar night.We examined the correlation between each factor and the polynya area under different temperature conditions.Previous studies have focused more on the effect of winds on the polynya,but the relationship between air temperature and the polynya area has not been fully investigated.Our study shows,eliminating the influence of winds,lower air temperature has a stronger positive correlation with the polynya area.The results show that the relationship between the polynya area and air temperature is more likely to be interactively influenced.As temperature drops,the relationship of the polynya area with air temperature becomes closer with increasing correlation coefficients.In the low temperature conditions,the correlation coefficients of the polynya area with air temperature are above 0.5,larger than that with the wind speed.展开更多
The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica(off Zhongshan Station)during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was ...The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica(off Zhongshan Station)during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters(e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed,which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.展开更多
A regional Arctic Ocean configuration of the Massachusetts Institute of Technology General Circulation Model(MITgcm)is applied to simulate the Arctic sea ice from 1991 to 2012.The simulations are evaluated by comparin...A regional Arctic Ocean configuration of the Massachusetts Institute of Technology General Circulation Model(MITgcm)is applied to simulate the Arctic sea ice from 1991 to 2012.The simulations are evaluated by comparing them with observations from different sources.The results show that MITgcm can reproduce the interannual and seasonal variability of the sea-ice extent,but underestimates the trend in sea-ice extent,especially in September.The ice concentration and thickness distributions are comparable to those from the observations,with most deviations within the observational uncertainties and less than 0.5 m,respectively.The simulated sea-ice extents are better correlated with observations in September,with a correlation coefficient of 0.95,than in March,with a correlation coefficient of 0.83.However,the distributions of sea-ice concentration are better simulated in March,with higher pattern correlation coefficients(0.98)than in September.When the model underestimates the atmospheric influence on the sea-ice evolution in March,deviations in the sea-ice concentration arise at the ice edges and are higher than those in September.In contrast,when the model underestimates the oceanic boundaries’influence on the September sea-ice evolution,disagreements in the distribution of the sea-ice concentration and its trend are found over most marginal seas in the Arctic Ocean.The uncertainties of the model,whereby it fails to incorporate the atmospheric information in March and oceanic information in September,contribute to varying model errors with the seasons.展开更多
Long term in situ atmospheric observation of the landfast ice nearby Zhongshan Station in the Prydz Bay was performed from April to November 2016. The in situ observation, including the conventional meteorological ele...Long term in situ atmospheric observation of the landfast ice nearby Zhongshan Station in the Prydz Bay was performed from April to November 2016. The in situ observation, including the conventional meteorological elements and turbulent flux, enabled this study to evaluate the sea ice surface energy budget process. Using in situ observations, three different reanalysis datasets from the European Centre for Medium-Range Weather Forecasts Interim Re-analysis(ERA-Interim), National Centers for Environmental Prediction Reanalysis2(NCEP R2), and Japanese 55-year Reanalysis(JRA55), and the Los Alamos sea ice model, CICE, output for surface fluxes were evaluated. The observed sensible heat flux(SH) and net longwave radiation showed seasonal variation with increasing temperature. Air temperature rose from the middle of October as the solar elevation angle increased.The ice surface lost more energy by outgoing longwave radiation as temperature increased, while the shortwave radiation showed obvious increases from the middle of October. The oceanic heat flux demonstrated seasonal variation and decreased with time, where the average values were 21 W/m^(2) and 11 W/m^(2), before and after August,respectively. The comparisons with in situ observations show that, SH and LE(latent heat flux) of JRA55 dataset had the smallest bias and mean absolute error(MAE), and those of NCEP R2 data show the largest differences.The ERA-Interim dataset had the highest spatial resolution, but performance was modest with bias and MAE between JRA55 and NCEP R2 compare with in situ observation. The CICE results(SH and LE) were consistent with the observed data but did not demonstrate the amplitude of inner seasonal variation. The comparison revealed better shortwave and longwave radiation stimulation based on the ERA-Interim forcing in CICE than the radiation of ERA-Interim. The average sea ice temperature decreased in June and July and increased after September,which was similar to the temperature measured by buoys, with a bias and MAE of 0.9℃ and 1.0℃, respectively.展开更多
Seasonal minimum Antarctic sea ice extent(SIE)in 2022 hit a new record low since recordkeeping began in 1978 of 1.9 million km^(2) on 25 February,0.17 million km^(2) lower than the previous record low set in 2017.Sign...Seasonal minimum Antarctic sea ice extent(SIE)in 2022 hit a new record low since recordkeeping began in 1978 of 1.9 million km^(2) on 25 February,0.17 million km^(2) lower than the previous record low set in 2017.Significant negative anomalies in the Bellingshausen/Amundsen Seas,the Weddell Sea,and the western Indian Ocean sector led to the new record minimum.The sea ice budget analysis presented here shows that thermodynamic processes dominate sea ice loss in summer through enhanced poleward heat transport and albedo-temperature feedback.In spring,both dynamic and thermodynamic processes contribute to negative sea ice anomalies.Specifically,dynamic ice loss dominates in the Amundsen Sea as evidenced by sea ice thickness(SIT)change,while positive surface heat fluxes contribute most to sea ice melt in the Weddell Sea.展开更多
Diabetes is a metabolic disorder by a chronic hyperglycemic condition because of defects in insulin secretion and insulin action or both. Minor cereals are often drought tolerant and fertilizer efficient. In this revi...Diabetes is a metabolic disorder by a chronic hyperglycemic condition because of defects in insulin secretion and insulin action or both. Minor cereals are often drought tolerant and fertilizer efficient. In this review we focus the content and bioavailability of phytochemicals in some minor cereals on the basis evidence for increasing plasma phytochemical concentrations and reducing oxidative stress as well as inflammation in humans. Phenolics and Flavanoids are major phytochemicals and may be available with high concentration in minor cereals but as tightly attached with cell wall, their bioavailability is mostly limited. Clinical trials concluded that vitamin E and other common antioxidants were not helpful for managing diabetic complications. Vicious cycles can cause type 1 DM, where as hypoglycemia can forward to down and regulate neuroendocrine. Increased phytochemical bioavailability may be achieved through bio processing of grains but the improvements might be small and have not yet led to changes in clinical associated with reduced risk of T2D. Furthermore, the effects of minor cereals against oxidative stress in healthy individuals can be very low or not occurred but systemic inflammation can be reduced in people after huge intake. More than 300 Indian medicinal plants have antidiabetic property but exact mechanisms for hypoglycemic action of many plants are still unknown. Further studies are required to pay attention toward direct role of minor cereal phytochemicals on alarming diseases diabetes.展开更多
In this paper,we propose an improved torque sensorless speed control method for electric assisted bicycle,this method considers the coordinate conversion.A low-pass filter is designed in disturbance observer to estima...In this paper,we propose an improved torque sensorless speed control method for electric assisted bicycle,this method considers the coordinate conversion.A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling.A DC motor provides assisted power driving,the assistance method is based on the realtime wheel angular velocity and coordinate system transformation.The effect of observer is proved,and the proposed method guarantees stability under disturbances.It is also compared to the existing methods and their performances are illustrated through simulations.The proposed method improves the performance both in rapidity and stability.展开更多
Device level performance of aqueous halide supercapatteries fabricated with equal electrode mass of activated carbon or graphene nanoplatelets has been characterized.It was revealed that the surface oxygen groups in t...Device level performance of aqueous halide supercapatteries fabricated with equal electrode mass of activated carbon or graphene nanoplatelets has been characterized.It was revealed that the surface oxygen groups in the graphitic structures of the nanoplatelets contributed toward a more enhanced charge storage capacity in bromide containing redox electrolytes.Moreover,the rate performance of the devices could be linked to the effect of the pore size of the carbons on the dynamics of the inactive alkali metal counterion of the redox halide salt.Additionally,the charge storage performance of aqueous halide supercapatteries with graphene nanoplatelets as the electrode material may be attributed to the combined effect of the porous structure on the dynamics of the non-active cations and a possible interaction of the Br^(-)/(Br_(2)+Br^(-)_(3))redox triple with the surface oxygen groups within the graphitic layer of the nanoplatelets.Generally,it has been shown that the surface groups and microstructure of electrode materials must be critically correlated with the redox electrolytes in the ongoing efforts to commercialize these devices.展开更多
The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studyi...The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studying and predicting weather patterns in the Antarctic are important for understanding their role in local-to-global processes and facilitating field studies and logistical operations in the Antarctic(e.g.,Walsh et al.,2018).Studies of climate change in the Antarctic are comparatively neglected compared to those of the Arctic.However,significant climate changes have occurred in the Antarctic in the past several decades,i.e.,a strong warming over the Antarctic Peninsula even with a recent minor cooling,a deepening of the Amundsen Sea low,a rapid warming of the upper ocean north of the circumpolar current,an increase of Antarctic sea ice since the late 1970s followed by a recent rapid decrease,and an accelerated ice loss from the Antarctic ice shelf/sheet since the late 1970s(e.g.,Turner et al.,2005;Raphael et al.,2016;Sallée,2018;Parkinson,2019;Rignot et al.,2019).Investigating recent climate change in the Antarctic and the underlying mechanisms are important for predicting future climate change and providing information to policymakers.展开更多
In recent decades,Arctic climate is warming at a rate of almost twice the global average(Osborne et al.,2018).The surface atmosphere and oceanic temperatures over Arctic Ocean increase leads to the rapid retreat of se...In recent decades,Arctic climate is warming at a rate of almost twice the global average(Osborne et al.,2018).The surface atmosphere and oceanic temperatures over Arctic Ocean increase leads to the rapid retreat of sea ice.The extension and thickness of sea ice in the Arctic,as well as the multi-year ice coverage,have decreased significantly.For example,the September sea ice extent in the Arctic,which is the end of the summer melt season,decreases at a rate of larger than 11%per decade(Polyakov et al.,2012).展开更多
[ Objective ] This study aimed to investigate the appropriate sowing dates of different millet varieties and analyzed the yield, agronomic traits and resist- ance of millet. [ Method ] Split-plot design was employed w...[ Objective ] This study aimed to investigate the appropriate sowing dates of different millet varieties and analyzed the yield, agronomic traits and resist- ance of millet. [ Method ] Split-plot design was employed with sowing date and millet variety assigned to the main plot and sub-plot, respectively, to investigate the effects of sowing dates on yield, agronomic traits and resistance of millet. [ Result] The results showed that early or late sowing would lead to yield reduction. Changsheng 07, Jingu 36 and Changnong 35 exhibited higher yield. Based on the yield, agronomic traits and resistance, the appropriate sowing date of Changsheng 07, Jingu 40 and Jingu 36 was May 13 ; the appropriate sowing date of Yangu 13 and Changnong 35 was May 20. [ Conclusion] The most appropriate sowing date of millet in Yan'an was May 10 to May 20. Key words Millet; Sowing date; Yield; Agronomic traits ; Resistance展开更多
基金funded by the National Key R&D Program of China (Grant No. 2022YFE0106300)the National Natural Science Foundation of China (Grant Nos. 41922044, 42106226 and 42106233)+4 种基金the Fundamental Research Funds for the Central Universities (Grant No. 3132023133)the China Postdoctoral Science Foundation (Grant No. 2020M683022)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2020B1515020025)the fundamental research funds for the Norges Forskningsråd. (Grant No. 328886)the Research Council of Norway for financial support through the research project “Multi-scale integration and digitalization of Arctic sea ice observations and predic tion models (328960)” and basic funding for research institutes
文摘The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding the sea ice concentration in the wind wave module;however,they simply suppose that the wind cannot penetrate the ice layer and ignore the possibility of wind forcing waves below the ice cover.To improve the simulation performance of wind wave modules in the marginal ice zone(MIZ),this study proposes a parameterization scheme by directly including the sea ice thickness.Instead of scaling the wind input with the fraction of open water,this new scheme allows partial wind input in ice-covered areas based on the ice thickness.Compared with observations in the Barents Sea in 2016,the new scheme appears to improve the modeled waves in the high-frequency band.Sensitivity experiments with and without wind wave modules show that wind waves can play an important role in areas with low sea ice concentration in the MIZ.
基金the National Natural Science Foundation of China(Grant No.41922044)the National Key Research and Development Program of China(Grants Nos.2019YFA0607000,2022YFE0106300)+2 种基金the National Natural Sci-ence Foundation of China(Grants Nos.42075028 and 42222502)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2021SP302)the fundamental research funds for the Norges Forskningsråd(Grant No.328886).
文摘A robust phenomenon termed the Arctic Amplification(AA)refers to the stronger warming taking place over the Arctic compared to the global mean.The AA can be confirmed through observations and reproduced in climate model simulations and shows significant seasonality and inter-model spread.This study focuses on the influence of surface type on the seasonality of AA and its inter-model spread by dividing the Arctic region into four surface types:ice-covered,ice-retreat,ice-free,and land.The magnitude and inter-model spread of Arctic surface warming are calculated from the difference between the abrupt-4×CO_(2)and pre-industrial experiments of 17 CMIP6 models.The change of effective thermal inertia(ETI)in response to the quadrupling of CO_(2) forcing is the leading mechanism for the seasonal energy transfer mechanism,which acts to store heat temporarily in summer and then release it in winter.The ETI change is strongest over the ice-retreat region,which is also responsible for the strongest AA among the four surface types.The lack of ETI change explains the nearly uniform warming pattern across seasons over the ice-free(ocean)region.Compared to other regions,the ice-covered region shows the maximum inter-model spread in JFM,resulting from a stronger inter-model spread in the oceanic heat storage term.However,the weaker upward surface turbulent sensible and latent heat fluxes tend to suppress the inter-model spread.The relatively small inter-model spread during summer is caused by the cancellation of the inter-model spread in ice-albedo feedback with that in the oceanic heat storage term.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0106300)the National Natural Science Foundation of China(Grant Nos.42105072,41941009,41922044)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515012209,2020B1515020025)the China Postdoctoral Science Foundation(Grant Nos.2021M693585)the Norges Forskningsråd(Grant No.328886).
文摘It is crucial to appropriately determine turbulent fluxes in numerical models.Using data collected in East Antarctica from 8 April to 26 November 2016,this study evaluates parameterization schemes for turbulent fluxes over the landfast seaice surface in five numerical models.The Community Noah Land Surface Model with Multi-Parameterizations Options(Noah_mp)best replicates the turbulent momentum flux,while the Beijing Climate System Model(BCC_CSM)produces the optimum sensible and latent heat fluxes.In particular,two critical issues of parameterization schemes,stability functions and roughness lengths,are investigated.Sensitivity tests indicate that roughness lengths play a decisive role in model performance.Based on the observed turbulent fluxes,roughness lengths over the landfast sea-ice surface are calculated.The results,which can provide a basis for setting up model parameters,reveal that the dynamic roughness length(z0m)increases with the increase of frictional velocity(u*)when u*≤0.4 m s^(−1) and fluctuates around 10^(−3 )m when u*>0.4 m s^(−1);thermal roughness length(z0t)is linearly related to the temperature gradient between air and sea-ice surface(ΔT)with a relation of lg(z0t)=−0.29ΔT−3.86;and the mean water vapor roughness length(z0q)in the specific humidity gradient(Δq)range ofΔq≤−0.6 g kg^(−1) is 10^(−6) m,3.5 times smaller than that in the range ofΔq˃−0.6 g kg^(−1).
基金the National Natural Science Foundation of China(Grant Nos.41922044 and 41941009)the National Key R&D Program of China(Grant No.2019YFA0607004 and 2022YFE0106300)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2020B1515020025 and 2019A1515110295)the Norges Forskningsråd(Grant No.328886).
文摘This study assesses sea ice thickness(SIT)from the historical run of the Coupled Model Inter-comparison Project Phase 6(CMIP6).The SIT reanalysis from the Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)product is chosen as the validation reference data.Results show that most models can adequately reproduce the climatological mean,seasonal cycle,and long-term trend of Arctic Ocean SIT during 1979-2014,but significant inter-model spread exists.Differences in simulated SIT patterns among the CMIP6 models may be related to model resolution and sea ice model components.By comparing the climatological mean and trend for SIT among all models,the Arctic SIT change in different seas during 1979-2014 is evaluated.Under the scenario of historical radiative forcing,the Arctic SIT will probably exponentially decay at-18%(10 yr)-1 and plausibly reach its minimum(equilibrium)of 0.47 m since the 2070s.
基金supported by the National Natural Science Foundation of China (31871709)the Construction of Support System for National Agricultural Green Development Advance Region of Qushui County,Tibet,China (QYXTZX-LS2022-01)+1 种基金the Key Project of Beijing Natural Science Foundation (6151002)the Startup Grants of Henan Agricultural University (30501038,30500823)。
文摘Maize growth and development are regulated by light quality,intensity and photoperiod.Cryptochromes are blue/ultraviolet-A light receptors involved in stem elongation,shade avoidance,and photoperiodic flowering.To investigate the function of cryptochrome 1(CRY1) in maize,where it is encoded by Zm CRY1,we obtained two Zm CRY1a genes(Zm CRY1a1 and Zm CRY1a2),both of which share the highest similarity with other gramineous plants,in particular rice CRY1a by phylogenetic analysis.In Arabidopsis,overexpression of Zm CRY1a genes promoted seedling de-etiolation under blue and white light,resulting in dwarfing of mature plants.In seedlings of the maize inbred line Zong 31(Zm CRY1aOE),overexpression of Zm CRY1a genes caused a reduction in the mesocotyl and first leaf sheath lengths due to down-regulation of genes influencing cell elongation.In mature transgenic maize plants,plant height,ear height,and internode length decreased in response to overexpression of Zm CRY1a genes.Expression of Zm CRY1a were insensitive to low blue light(LBL)-induced shade avoidance syndrome(SAS) in Arabidopsis and maize.This prompted us to investigate the regulatory role of the gibberellin and auxin metabolic pathways in the response of Zm CRY1a genes to LBL treatment.We confirmed a link between Zm CRY1a expression and hormonal influence on the growth and development of maize under LBL-induced SAS.These results reveal that Zm CRY1a has a relatively conservative function in regulating maize photomorphogenesis and may guide new strategies for breeding high density-tolerant maize cultivars.
基金the National Natural Science Foundation of China(No.41922044,41941009)the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515020025)+1 种基金the fundamental research funds for the Norges Forskningsråd(No.328886)C Min acknowledges support from the China Scholarship Council(No.202006380131).
文摘Sea ice,one of the most dominant barriers to Arctic shipping,has decreased dramatically over the past four decades.Arctic maritime transport is hereupon growing in recent years.To produce a long-term assessment of trans-Arctic accessibility,we systematically revisit the daily Arctic navigability with a view to the combined effects of sea ice thickness and concentration throughout the period 1979−2020.The general trends of Navigable Windows(NW)in the Northeast Passage show that the number of navigable days is steadily growing and reached 89±16 days for Open Water(OW)ships and 163±19 days for Polar Class 6(PC6)ships in the 2010s,despite high interannual and interdecadal variability in the NWs.More consecutive NWs have emerged annually for both OW ships and PC6 ships since 2005 because of the faster sea ice retreat.Since the 1980s,the number of simulated Arctic routes has continuously increased,and optimal navigability exists in these years of record-low sea ice extent(e.g.,2012 and 2020).Summertime navigability in the East Siberian and Laptev Seas,on the other hand,varies dramatically due to changing sea ice conditions.This systematic assessment of Arctic navigability provides a reference for better projecting the future trans-Arctic shipping routes.
文摘The Arctic climate system has changed rapidly during recent decades with a two-four times faster warming rate than the global average subject to the uncertainties of analysis datasets and approaches.These changes have apparently resulted in broader and sizeable impacts within the Arctic,in the low/mid-latitudes,and globally.The importance of these changes and impacts makes the Arctic stand out within the global climate systems,drawing great attention and interests from the climate research community,the general public,and the government sector.One of the persistent,leading-edge topics in climate stud-ies during recent decades has therefore been to improve understanding of the underlying driving mechanisms,evaluate socioe-conomic and ecological impacts,and enhance the ability of the prediction and projections of Arctic climate changes.
基金funded by the Global Change Research Program of China(Grant No.2015CB953900)the Key Program of the National Natural Science Foundation of China(Grant Nos.41330960 and 41406208)+1 种基金the Canada Research Chairs Program,NSERCCanadian Federal IPY Program Office
文摘The Arctic sea-ice extent has shown a declining trend over the past 30 years. Ice coverage reached historic minima in 2007 and again in 2012. This trend has recently been assessed to be unique over at least the last 1450 years. In the summer of 2010, a very low sea-ice concentration(SIC) appeared at high Arctic latitudes—even lower than that of surrounding pack ice at lower latitudes. This striking low ice concentration—referred to here as a record low ice concentration in the central Arctic(CARLIC)—is unique in our analysis period of 2003–15, and has not been previously reported in the literature. The CARLIC was not the result of ice melt, because sea ice was still quite thick based on in-situ ice thickness measurements.Instead, divergent ice drift appears to have been responsible for the CARLIC. A high correlation between SIC and wind stress curl suggests that the sea ice drift during the summer of 2010 responded strongly to the regional wind forcing. The drift trajectories of ice buoys exhibited a transpolar drift in the Atlantic sector and an eastward drift in the Pacific sector,which appeared to benefit the CARLIC in 2010. Under these conditions, more solar energy can penetrate into the open water,increasing melt through increased heat flux to the ocean. We speculate that this divergence of sea ice could occur more often in the coming decades, and impact on hemispheric SIC and feed back to the climate.
基金The National Natural Science Foundation of China under contract Nos 41876212,41406218 and 41676176the Polar Strategy Project from Chinese Arctic and Antarctic Administration under contract No.20120317the Opening Fund of Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions,CAS,under contract Nos LPCC2018001 and LPCC2018005
文摘Annual observations of first-year ice(FYI) and second-year ice(SYI) near Zhongshan Station, East Antarctica,were conducted for the first time from December 2011 to December 2012. Melt ponds appeared from early December 2011. Landfast ice partly broke in late January, 2012 after a strong cyclone. Open water was refrozen to form new ice cover in mid-February, and then FYI and SYI co-existed in March with a growth rate of 0.8 cm/d for FYI and a melting rate of 2.7 cm/d for SYI. This difference was due to the oceanic heat flux and the thickness of ice,with weaker heat flux through thicker ice. From May onward, FYI and SYI showed a similar growth by 0.5 cm/d.Their maximum thickness reached 160.5 cm and 167.0 cm, respectively, in late October. Drillings showed variations of FYI thickness to be generally less than 1.0 cm, but variations were up to 33.0 cm for SYI in March,suggesting that the SYI bottom was particularly uneven. Snow distribution was strongly affected by wind and surface roughness, leading to large thickness differences in the different sites. Snow and ice thickness in Nella Fjord had a similar "east thicker, west thinner" spatial distribution. Easterly prevailing wind and local topography led to this snow pattern. Superimposed ice induced by snow cover melting in summer thickened multi-year ice,causing it to be thicker than the snow-free SYI. The estimated monthly oceanic heat flux was ~30.0 W/m2 in March–May, reducing to ~10.0 W/m2 during July–October, and increasing to ~15.0 W/m2 in November. The seasonal change and mean value of 15.6 W/m2 was similar to the findings of previous research. The results can be used to further our understanding of landfast ice for climate change study and Chinese Antarctic Expedition services.
基金the National Natural Science Foundation of China(Grant No.41830536,Grant No.41676190,and Grant No.41941009)the Fundamental Research Funds for the Central Universities(Grant No.12500-312231103)The authors thank the University of Bremen for providing the AMSR-E,AMSR-2 and SSMIS SIC data,as well as the University of Wisconsin-Madison Automatic Weather Station Program(NSF Grant No.ANT-1543305)。
文摘Antarctic polynyas play an important role in regional atmosphere?ice?ocean interactions and are considered to help generate the global deep ocean conveyer belt.Polynyas therefore have a potential impact on the Earth’s climate in terms of the production of sea ice and high-salinity shelf water.In this study,we investigated the relationship between the area of the Terra Nova Bay polynya and the air temperature as well as the eastward and northward wind based on the ERA5 and ERAInterim reanalysis datasets and observations from automatic weather stations during the polar night.We examined the correlation between each factor and the polynya area under different temperature conditions.Previous studies have focused more on the effect of winds on the polynya,but the relationship between air temperature and the polynya area has not been fully investigated.Our study shows,eliminating the influence of winds,lower air temperature has a stronger positive correlation with the polynya area.The results show that the relationship between the polynya area and air temperature is more likely to be interactively influenced.As temperature drops,the relationship of the polynya area with air temperature becomes closer with increasing correlation coefficients.In the low temperature conditions,the correlation coefficients of the polynya area with air temperature are above 0.5,larger than that with the wind speed.
基金supported by the National Natural Science Foundation of China(Grant Nos.41006115 and 41376005)the Chinese Polar Environmental Comprehensive Investigation and Assessment Programthe Chinese National Key Basic Research Project(2011CB309704)
文摘The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica(off Zhongshan Station)during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters(e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed,which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.
基金This work was supported by the National Key R&D Program of China(Grant No.2016YFC1402705)the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC010)+1 种基金the National Natural Science Foundation of China(Grant Nos.41876012 and 41861144015)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB42000000)。
文摘A regional Arctic Ocean configuration of the Massachusetts Institute of Technology General Circulation Model(MITgcm)is applied to simulate the Arctic sea ice from 1991 to 2012.The simulations are evaluated by comparing them with observations from different sources.The results show that MITgcm can reproduce the interannual and seasonal variability of the sea-ice extent,but underestimates the trend in sea-ice extent,especially in September.The ice concentration and thickness distributions are comparable to those from the observations,with most deviations within the observational uncertainties and less than 0.5 m,respectively.The simulated sea-ice extents are better correlated with observations in September,with a correlation coefficient of 0.95,than in March,with a correlation coefficient of 0.83.However,the distributions of sea-ice concentration are better simulated in March,with higher pattern correlation coefficients(0.98)than in September.When the model underestimates the atmospheric influence on the sea-ice evolution in March,deviations in the sea-ice concentration arise at the ice edges and are higher than those in September.In contrast,when the model underestimates the oceanic boundaries’influence on the September sea-ice evolution,disagreements in the distribution of the sea-ice concentration and its trend are found over most marginal seas in the Arctic Ocean.The uncertainties of the model,whereby it fails to incorporate the atmospheric information in March and oceanic information in September,contribute to varying model errors with the seasons.
基金The National Key R&D Program of China under contract No. 2018YFA0605903the National Natural Science Foundation of China under contract Nos 41941009, 41922044 and 41876212the Guangdong Basic and Applied Basic Research Foundation under contract No. 2020B1515020025。
文摘Long term in situ atmospheric observation of the landfast ice nearby Zhongshan Station in the Prydz Bay was performed from April to November 2016. The in situ observation, including the conventional meteorological elements and turbulent flux, enabled this study to evaluate the sea ice surface energy budget process. Using in situ observations, three different reanalysis datasets from the European Centre for Medium-Range Weather Forecasts Interim Re-analysis(ERA-Interim), National Centers for Environmental Prediction Reanalysis2(NCEP R2), and Japanese 55-year Reanalysis(JRA55), and the Los Alamos sea ice model, CICE, output for surface fluxes were evaluated. The observed sensible heat flux(SH) and net longwave radiation showed seasonal variation with increasing temperature. Air temperature rose from the middle of October as the solar elevation angle increased.The ice surface lost more energy by outgoing longwave radiation as temperature increased, while the shortwave radiation showed obvious increases from the middle of October. The oceanic heat flux demonstrated seasonal variation and decreased with time, where the average values were 21 W/m^(2) and 11 W/m^(2), before and after August,respectively. The comparisons with in situ observations show that, SH and LE(latent heat flux) of JRA55 dataset had the smallest bias and mean absolute error(MAE), and those of NCEP R2 data show the largest differences.The ERA-Interim dataset had the highest spatial resolution, but performance was modest with bias and MAE between JRA55 and NCEP R2 compare with in situ observation. The CICE results(SH and LE) were consistent with the observed data but did not demonstrate the amplitude of inner seasonal variation. The comparison revealed better shortwave and longwave radiation stimulation based on the ERA-Interim forcing in CICE than the radiation of ERA-Interim. The average sea ice temperature decreased in June and July and increased after September,which was similar to the temperature measured by buoys, with a bias and MAE of 0.9℃ and 1.0℃, respectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.41941009,41922044,and 42006191)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020B1515020025)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.19lgzd07)the Norges Forskningsråd(Grant no.328886).
文摘Seasonal minimum Antarctic sea ice extent(SIE)in 2022 hit a new record low since recordkeeping began in 1978 of 1.9 million km^(2) on 25 February,0.17 million km^(2) lower than the previous record low set in 2017.Significant negative anomalies in the Bellingshausen/Amundsen Seas,the Weddell Sea,and the western Indian Ocean sector led to the new record minimum.The sea ice budget analysis presented here shows that thermodynamic processes dominate sea ice loss in summer through enhanced poleward heat transport and albedo-temperature feedback.In spring,both dynamic and thermodynamic processes contribute to negative sea ice anomalies.Specifically,dynamic ice loss dominates in the Amundsen Sea as evidenced by sea ice thickness(SIT)change,while positive surface heat fluxes contribute most to sea ice melt in the Weddell Sea.
文摘Diabetes is a metabolic disorder by a chronic hyperglycemic condition because of defects in insulin secretion and insulin action or both. Minor cereals are often drought tolerant and fertilizer efficient. In this review we focus the content and bioavailability of phytochemicals in some minor cereals on the basis evidence for increasing plasma phytochemical concentrations and reducing oxidative stress as well as inflammation in humans. Phenolics and Flavanoids are major phytochemicals and may be available with high concentration in minor cereals but as tightly attached with cell wall, their bioavailability is mostly limited. Clinical trials concluded that vitamin E and other common antioxidants were not helpful for managing diabetic complications. Vicious cycles can cause type 1 DM, where as hypoglycemia can forward to down and regulate neuroendocrine. Increased phytochemical bioavailability may be achieved through bio processing of grains but the improvements might be small and have not yet led to changes in clinical associated with reduced risk of T2D. Furthermore, the effects of minor cereals against oxidative stress in healthy individuals can be very low or not occurred but systemic inflammation can be reduced in people after huge intake. More than 300 Indian medicinal plants have antidiabetic property but exact mechanisms for hypoglycemic action of many plants are still unknown. Further studies are required to pay attention toward direct role of minor cereal phytochemicals on alarming diseases diabetes.
基金supported by the National Natural Science Foundation of China(51775325)Hong Kong Scholars Program of China(XJ2013015)。
文摘In this paper,we propose an improved torque sensorless speed control method for electric assisted bicycle,this method considers the coordinate conversion.A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling.A DC motor provides assisted power driving,the assistance method is based on the realtime wheel angular velocity and coordinate system transformation.The effect of observer is proved,and the proposed method guarantees stability under disturbances.It is also compared to the existing methods and their performances are illustrated through simulations.The proposed method improves the performance both in rapidity and stability.
基金funding from the International Doctoral Innovation CentreNingbo Education Bureau+2 种基金Ningbo Science and Technology Bureauthe University of NottinghamNingbo Municipal Government(3315 Plan and 2014A35001-1)
文摘Device level performance of aqueous halide supercapatteries fabricated with equal electrode mass of activated carbon or graphene nanoplatelets has been characterized.It was revealed that the surface oxygen groups in the graphitic structures of the nanoplatelets contributed toward a more enhanced charge storage capacity in bromide containing redox electrolytes.Moreover,the rate performance of the devices could be linked to the effect of the pore size of the carbons on the dynamics of the inactive alkali metal counterion of the redox halide salt.Additionally,the charge storage performance of aqueous halide supercapatteries with graphene nanoplatelets as the electrode material may be attributed to the combined effect of the porous structure on the dynamics of the non-active cations and a possible interaction of the Br^(-)/(Br_(2)+Br^(-)_(3))redox triple with the surface oxygen groups within the graphitic layer of the nanoplatelets.Generally,it has been shown that the surface groups and microstructure of electrode materials must be critically correlated with the redox electrolytes in the ongoing efforts to commercialize these devices.
基金the National Key R&D Program of China(Grant No.2018YFA0605901).
文摘The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studying and predicting weather patterns in the Antarctic are important for understanding their role in local-to-global processes and facilitating field studies and logistical operations in the Antarctic(e.g.,Walsh et al.,2018).Studies of climate change in the Antarctic are comparatively neglected compared to those of the Arctic.However,significant climate changes have occurred in the Antarctic in the past several decades,i.e.,a strong warming over the Antarctic Peninsula even with a recent minor cooling,a deepening of the Amundsen Sea low,a rapid warming of the upper ocean north of the circumpolar current,an increase of Antarctic sea ice since the late 1970s followed by a recent rapid decrease,and an accelerated ice loss from the Antarctic ice shelf/sheet since the late 1970s(e.g.,Turner et al.,2005;Raphael et al.,2016;Sallée,2018;Parkinson,2019;Rignot et al.,2019).Investigating recent climate change in the Antarctic and the underlying mechanisms are important for predicting future climate change and providing information to policymakers.
基金The National Key R&D Program of China under contract No.2016YFC1402700
文摘In recent decades,Arctic climate is warming at a rate of almost twice the global average(Osborne et al.,2018).The surface atmosphere and oceanic temperatures over Arctic Ocean increase leads to the rapid retreat of sea ice.The extension and thickness of sea ice in the Arctic,as well as the multi-year ice coverage,have decreased significantly.For example,the September sea ice extent in the Arctic,which is the end of the summer melt season,decreases at a rate of larger than 11%per decade(Polyakov et al.,2012).
基金Supported by Key Project in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(2014BAD07B01)National Millet and Prosomillet Industrial Technology System(CARS-07-12.5)Project of Minor Grain Crop Industrial Technology System of Shaanxi Province
文摘[ Objective ] This study aimed to investigate the appropriate sowing dates of different millet varieties and analyzed the yield, agronomic traits and resist- ance of millet. [ Method ] Split-plot design was employed with sowing date and millet variety assigned to the main plot and sub-plot, respectively, to investigate the effects of sowing dates on yield, agronomic traits and resistance of millet. [ Result] The results showed that early or late sowing would lead to yield reduction. Changsheng 07, Jingu 36 and Changnong 35 exhibited higher yield. Based on the yield, agronomic traits and resistance, the appropriate sowing date of Changsheng 07, Jingu 40 and Jingu 36 was May 13 ; the appropriate sowing date of Yangu 13 and Changnong 35 was May 20. [ Conclusion] The most appropriate sowing date of millet in Yan'an was May 10 to May 20. Key words Millet; Sowing date; Yield; Agronomic traits ; Resistance