The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013...The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013, forced using the data of the Russian weather station Kotel＇ny Island and ECMWF reanalyses. Thermal growth and decay of ice were reproduced well, and the maximum annual ice thickness and breakup day became 1.64 m and the end of July. Oceanic heat flux was 2 W.m^-2 in winter and raised to 25 W.m^-2 in summer, albedo was 0.3-0.8 depending on the surface type （snow/ice and wet/dry）. The model outcome showed sensitivity to the albedo, air temperature and oceanic heat flux. The modelled snow cover was less than 10 cm having a small influence on the ice thickness. In situ sea ice thickness in the East Siberian Sea is rarely available in publications. This study provides a method for quantitative ice thickness estimation by modelling. The result can be used as a proxy to understand the sea ice conditions on the Eurasian Arctic coast, which is important for shipping and high-resolution Arctic climate modelling.展开更多
The growth kinetics of ice are modeled using the Water Potential from Adaptive Force Matching for Ice and Liquid （WAIL） potential with molecular dynamics. The all-atom WAIL model provides a good description of the p...The growth kinetics of ice are modeled using the Water Potential from Adaptive Force Matching for Ice and Liquid （WAIL） potential with molecular dynamics. The all-atom WAIL model provides a good description of the properties of both ice and liquid with an equilibrium temperature of 270 K at 1 bar. The growth kinetics captured by this model can thus reflect those of real ice. Our simulation indicates that the growth rate of ice on the basal plane is fastest at approximately 20 K supercooling, consistent with experimental findings, where the growth rate increases monotonically as the supercooling increases to 18 K. The key factors that control the growth kinetics leading to the optimal growth temperature are investigated. The simulation revealed a bilayer-by-bilayer growth mechanism on the basal plane that proceeds in two steps. Whereas water molecules lose translational motion and become ice-like quickly, the establishment of orientational order to form ice is a slow and activated process. Enhanced by the templating effect of sublayers, the rapid reduction in translational motion in the formation of the prefreezing layer might explain the significantly faster growth rate relative to the nucleation rate of water. Whereas remelting of the prefreezing layer is observed at low supercooling and may be responsible for the lower growth rate close to the melting temperature, the slow orientational ordering of the prefreezing layer into the final ice conformation is partly responsible for the reduced growth rate at deeper supercooling.展开更多
High total dissolved solids （TDS） content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the o...High total dissolved solids （TDS） content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the object of study. Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness. TDS profiles were drawn to show the distribution of TDS and to describe TDS migration. The results showed that about 80% （that is 3.602x108 kg） of TDS migrated from ice to water during the whole growth period of ice. Within ice layer, TDS migration only occurred during initial ice-on period, and then perished. The TDS in ice decreased with increasing ice thickness, following a negative exponential-like trend. Within un- der-ice water, the TDS migrated from ice-water interface to the entire water column under the effect of concentra- tion gradient until the water TDS content was uniform. In winter, 6.044x 107 kg （16.78% of total TDS） TDS migrated from water to sedirnent, which indicated that winter is the best time for dredging sediment. The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River. The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate, which reveals that ice growth rate is one of the determinants of TDS migration. The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.展开更多
The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing w...The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing winter oil spill accidents. This study applied the three-dimensional free surface to establish a high-resolution hydrodynamic model and simulate tidal distributions in the Bohai Sea. Then, the oil spill model of the open sea area and thermodynamic model were combined to establish a numerical model for the Bohai oil spill during the winter sea ice period. The hydrodynamic model and sea ice growth and melting model were verified, and the parameters were adjusted based on the measured values, which indicate that the numerical model established in this paper is of high accuracy,stability and ubiquity. Finally, after checking the calculations repeatedly, the diffusion coefficient for the Bohai Sea was determined to be 1.0×10^(–7 )m^2/s. It is better that the comprehensive weathering attenuation coefficient is lower than that of a non-winter oil spill, with 1.3×10^(–7 )m^2/s being the most appropriate coefficient. This study can provide the reliable technical support for the operational safety and reduction in losses caused by winter oil spill accidents for the petroleum industry.展开更多
基金supported by research funding from the National Natural Science Foundation of China (Grant nos. 41428603, 41376186, 41476170)the EU FP7 Project Eu Ru CAS(European-Russian Centre for Cooperation in the Arctic and Sub-Arctic Environmental and Climate Research,Grant no.295068)+2 种基金Academy of Finland (Grant nos. 11409391, 259537)the Liaoning Educational Committee Foundation (Grant no. L2013497)the Ocean Public Welfare Scientific Research Project of China (Grant nos. 201205007, 201205007-2)
文摘The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013, forced using the data of the Russian weather station Kotel＇ny Island and ECMWF reanalyses. Thermal growth and decay of ice were reproduced well, and the maximum annual ice thickness and breakup day became 1.64 m and the end of July. Oceanic heat flux was 2 W.m^-2 in winter and raised to 25 W.m^-2 in summer, albedo was 0.3-0.8 depending on the surface type （snow/ice and wet/dry）. The model outcome showed sensitivity to the albedo, air temperature and oceanic heat flux. The modelled snow cover was less than 10 cm having a small influence on the ice thickness. In situ sea ice thickness in the East Siberian Sea is rarely available in publications. This study provides a method for quantitative ice thickness estimation by modelling. The result can be used as a proxy to understand the sea ice conditions on the Eurasian Arctic coast, which is important for shipping and high-resolution Arctic climate modelling.
基金This work was supported by the National Basic Research Program of China under Grant No. 2015CB856801, the National Natural Science Foundation of China under Grant Nos. 11525520 and 11290162/A040106, and the National Key R＆D Program under Grant No. 2016YFA0300901. The computer re- sources for this study were provided by the Arkansas High Per- formance Computational Center through grant MRI-R2 0959124 provided by the NSF of USA.
文摘The growth kinetics of ice are modeled using the Water Potential from Adaptive Force Matching for Ice and Liquid （WAIL） potential with molecular dynamics. The all-atom WAIL model provides a good description of the properties of both ice and liquid with an equilibrium temperature of 270 K at 1 bar. The growth kinetics captured by this model can thus reflect those of real ice. Our simulation indicates that the growth rate of ice on the basal plane is fastest at approximately 20 K supercooling, consistent with experimental findings, where the growth rate increases monotonically as the supercooling increases to 18 K. The key factors that control the growth kinetics leading to the optimal growth temperature are investigated. The simulation revealed a bilayer-by-bilayer growth mechanism on the basal plane that proceeds in two steps. Whereas water molecules lose translational motion and become ice-like quickly, the establishment of orientational order to form ice is a slow and activated process. Enhanced by the templating effect of sublayers, the rapid reduction in translational motion in the formation of the prefreezing layer might explain the significantly faster growth rate relative to the nucleation rate of water. Whereas remelting of the prefreezing layer is observed at low supercooling and may be responsible for the lower growth rate close to the melting temperature, the slow orientational ordering of the prefreezing layer into the final ice conformation is partly responsible for the reduced growth rate at deeper supercooling.
基金Financial support was provided by the National Natural Science Foundation of China (50569002,50669004 and 51069007)Natural Science Foundation of Inner Mongolia (200711020604)Key Project from Department of Water Resources of Inner Mongolia (20080105)
文摘High total dissolved solids （TDS） content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the object of study. Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness. TDS profiles were drawn to show the distribution of TDS and to describe TDS migration. The results showed that about 80% （that is 3.602x108 kg） of TDS migrated from ice to water during the whole growth period of ice. Within ice layer, TDS migration only occurred during initial ice-on period, and then perished. The TDS in ice decreased with increasing ice thickness, following a negative exponential-like trend. Within un- der-ice water, the TDS migrated from ice-water interface to the entire water column under the effect of concentra- tion gradient until the water TDS content was uniform. In winter, 6.044x 107 kg （16.78% of total TDS） TDS migrated from water to sedirnent, which indicated that winter is the best time for dredging sediment. The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River. The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate, which reveals that ice growth rate is one of the determinants of TDS migration. The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.
基金financially supported by the Natural Science Foundation of Liaoning Province,China(Grant No.20180551183)the Scientific Research Foundation for Doctoral Scholars of Liaoning Province,China(Grant No.201601388)the Key Research and Development Project of Liaoning Province,China(Grant No.2018228004)
文摘The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing winter oil spill accidents. This study applied the three-dimensional free surface to establish a high-resolution hydrodynamic model and simulate tidal distributions in the Bohai Sea. Then, the oil spill model of the open sea area and thermodynamic model were combined to establish a numerical model for the Bohai oil spill during the winter sea ice period. The hydrodynamic model and sea ice growth and melting model were verified, and the parameters were adjusted based on the measured values, which indicate that the numerical model established in this paper is of high accuracy,stability and ubiquity. Finally, after checking the calculations repeatedly, the diffusion coefficient for the Bohai Sea was determined to be 1.0×10^(–7 )m^2/s. It is better that the comprehensive weathering attenuation coefficient is lower than that of a non-winter oil spill, with 1.3×10^(–7 )m^2/s being the most appropriate coefficient. This study can provide the reliable technical support for the operational safety and reduction in losses caused by winter oil spill accidents for the petroleum industry.
