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1.
A. N. Chetyrbotskii 《Russian Meteorology and Hydrology》2010,35(3):211-217
The model is constructed based on the concepts of the character of thermal evolution of the sea ice cover thickness. The dynamics
of the ice thickness and that of the melt water forming in the ice cover are considered at the stage of melting. The space
limitation of the marine environment for the ice is taken into account both for the stage of the ice cover formation and for
the stage of its melting. The model is investigated analytically. The parametric identification of the model and the estimation
of its adequacy are performed based on sampling distributions of the ice cover thickness in the Sea of Japan. 相似文献
2.
A. N. Chetyrbotskii 《Russian Meteorology and Hydrology》2007,32(1):43-49
A model of space-time dynamics of the sea ice cover in which individual ice floes undergo a successive change in size is considered. The formation and melting of ice floes, their aggregation, and the formation of hummocks are taken into account. A parametric model identification is done based on a sample of ice cover area and thickness distribution in the Japan Sea. 相似文献
3.
The effect of snow on Antarctic sea ice simulations in a coupled atmosphere-sea ice model 总被引：1，自引：0，他引：1
The effect of a snow cover on sea ice accretion and ablation is estimated based on the ‘zero-layer’ version sea ice model
of Semtner, and is examined using a coupled atmosphere-sea ice model including feedbacks and ice dynamics effects. When snow
is disregarded in the coupled model the averaged Antarctic sea ice becomes thicker. When only half of the snowfall predicted
by the atmospheric model is allowed to land on the ice surface sea ice gets thicker in most of the Weddell and Ross Seas but
thinner in East Antarctic in winter, with the average slightly thicker. When twice as much snowfall as predicted by the atmospheric
model is assumed to land on the ice surface sea ice also gets much thicker due to the large increase of snow-ice formation.
These results indicate the importance of the correct simulation of the snow cover over sea ice and snow-ice formation in the
Antarctic. Our results also illustrate the complex feedback effects of the snow cover in global climate models. In this study
we have also tested the use of a mean value of 0.16 Wm-1 K-1 instead of 0.31 for the thermal conductivity of snow in the coupled model, based on the most recent observations in the eastern
Antarctic and Bellingshausen and Amundsen Seas, and have found that the sea ice distribution changes greatly, with the ice
becoming much thinner by about 0.2 m in the Antarctic and about 0.4 m in the Arctic on average. This implies that the magnitude
of the thermal conductivity of snow is of considerable importance for the simulation of the sea ice distribution. An appropriate
value of the thermal conductivity of snow is as crucial as the depth of the snow layer and the snowfall rate in a sea ice
model. The coupled climate models require accurate values of the effective thermal conductivity of snow from observations
for validating the simulated sea ice distribution under the present climate conditions.
Received: 20 November 1997/Accepted: 27 July 1998 相似文献
4.
Considered are the peculiarities of fast ice formation in the Antarctic coastal waters. It is noted that the fine-crystalline ice with the chaotic orientation of crystals is mainly developed in the surface layers of the ice cover as well as the ice formed due to the infiltration of the sea water and its subsequent freezing in the lower layers of the snow cover. It is demonstrated that under the conditions of coastal Antarctic, the lamination of the structure during the period of ice cover formation and its subsequent development is the result of heavy precipitation in the form of snow and the formation of the large amount of snow sludge and crystals of intrawater ice (frazil ice) on the open water. The main distinctive feature of the Antarctic sea ice is its seasonal stratification with the formation of the surface layer of recrystallized ice and underlying destructive layers including the water interlayer in the ice column. The provision of the safety of overice movement of machinery requires the development of methods of continuous remote control of the snow-ice stratum of the fast ice. 相似文献
5.
A. N. Chetyrbotskii 《Russian Meteorology and Hydrology》2007,32(5):313-319
Results of large-scale mathematical modeling of sea ice cover evolution are analyzed. Special attention is given to formalization of the thermal effect of the atmosphere on ice cover evolution. A model of sea ice cover evolution is developed in which thermal effects of the environment on ice cover and aggregation, fragmentation, and hummocking of ice are taken into account. The model adequacy is estimated by sample distribution of area and thickness of ice cover in the Sea of Japan. 相似文献
6.
L. R. Lukin 《Russian Meteorology and Hydrology》2013,38(7):480-485
Considered is the theoretical mechanism of the formation of immovable ice cover along the coast (the fast ice) from the seasonal ice and the mechanism of its destruction. It is demonstrated that the process of formation and spread of the winter stable fast ice is determined by simultaneous impact of several factors: the morphometry of the coast and bottom, the width of the close ice, dynamic effects that shear stress forces of the flow and wind make on the ice, the duration of maintaining the condition of immobility and freezing (adhesion) of the ice, the thickness of adhered ice, and the intensity of thermal growth of ice from below. It is revealed that the permanent factor is the morphometry of coasts and the bottom while the other factors have temporal variability of various scales. 相似文献
7.
8.
Xiaoyi SHEN Chang-Qing KE Bin CHENG Wentao XIA Mengmeng LI Xuening YU Haili LI 《大气科学进展》2021,38(9):1474-1485
In August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled iceocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978(mean value of 1.1 m, compared to the average value of 2.8 m during 1978-2017) and the modest southerly wind caused by a positive North Atlantic Oscillation(mean value of 0.82, compared to the climatological value of-0.02) were responsible for the formation and maintenance of this polynya. The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind. Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region. 相似文献
9.
Shupo Ma Libo Zhou Han Zou Meigen Zhang Peng Li 《Meteorology and Atmospheric Physics》2013,120(1-2):45-51
Observations and model simulations were conducted in a typical Himalayan valley to investigate the role of snow/ice cover in the formation of the local diurnal wind. An unusual local circulation was observed in the Himalayas with a strong down-valley flow dominant from noon to midnight, greatly differing from those in other mountainous regions. Two experiments with snow/ice cover included/excluded were performed using the Regional Atmospheric Modeling System (RAMS) to reconstruct the Himalayan circulation, and to reveal the role of snow/ice in this circulation. The results show that the wind system in the Himalayas is composed of both glacier winds driven by the snow/ice cover and classical mountain-valley winds. In particular, the glacier winds establish the distinctive feature of the Himalayan local circulation, i.e., the strong down-valley flow in the afternoon. 相似文献
10.
S. V. Klyachkin 《Russian Meteorology and Hydrology》2011,36(3):193-199
The technique and results of computations of statistical parameters of ice pile-up formation on the western coast of the northern Caspian Sea are presented. The dynamic model of ice pile-up formation on the shores is described. The main ice, meteorological, and morphologic factors influencing the shore pile-up formation are analyzed. The test computation enabling to estimate the model adequacy is described. The estimation principle of the probability of the formation of the ice pile-up of certain size is given and the distribution functions of geometrical parameters of the pile-ups on the western coast of the northern Caspian Sea are obtained. The limits of the proposed model are specially stipulated. 相似文献
11.
Juliane Bernhardt Christof Engelhardt Georgiy Kirillin J?rg Matschullat 《Climatic change》2012,112(3-4):791-817
Rising northern hemispheric mean air temperatures reduce the amount of winter lake ice. These changes in lake ice cover must be understood in terms of resulting effects on lake ecosystems. Accurate predictions of lake ice phenology are essential to assess resulting impact. We applied the one-dimensional physical lake model FLake to analyse past variability in ice cover timing, intensity and duration of Berlin-Brandenburg lakes. The observed ice phenology in two lakes in the period 1961–2007 was reconstructed by FLake reasonably well and with higher accuracy than by state-of-the-art linear regression models. Additional modelling results of FLake for 38 Berlin-Brandenburg lakes, observed in the winter of 2008/09, were quite satisfactory and adequately reproduced the effects of varying lake morphology and trophic state. Observations and model results showed that deeper and clearer lakes had more ice-free winters, later ice cover freezing and earlier ice cover thawing dates, resulting in shorter ice-covered periods and fewer ice-covered days than shallow and less clear lakes. The 1947–2007 model hindcasts were implemented using FLake for eight Berlin-Brandenburg lakes without ice phenology observations. Results demonstrated past trends of later ice start and earlier ice end, shorter ice cover duration and an increase in ice-free winters. 相似文献
12.
Modelling the influence of snow accumulation and snow-ice formation on the seasonal cycle of the Antarctic sea-ice cover 总被引：5，自引：5，他引：0
Recent observational and numerical studies of the maritime snow cover in the Antarctic suggest that snow on top of sea ice
plays a major role in shaping the seasonal growth and decay of the ice pack in the Southern Ocean. Here, we make a quantitative
assessment of the importance of snow accumulation in controlling the seasonal cycle of the ice cover with a coupled snow–sea-ice–upper-ocean
model. The model takes into account snow and ice sublimation and snow deposition by condensation. A parametrisation of the
formation of snow ice (ice resulting from the freezing of a mixture of snow and seawater produced by flooding of the ice floes)
is also included. Experiments on the sensitivity of the snow–sea-ice system to variations in the sublimation/condensation
rate, the precipitation rate, and the amount of snowfall transported by the wind into leads are discussed. Although we focus
on the model response in the Southern Hemisphere, results for the Arctic are also discussed in some cases to highlight the
relative importance of the processes under study in both hemispheres. It is found that the snow loss by sublimation can account
for the removal of 0.45 m of snow per year in the Antarctic and that this loss significantly affects the total volume of snow
ice. A precipitation decrease of 50% is conducive to large reductions in the Antarctic snow and snow-ice volumes, but it leads
only to an 8% decrease in the annual mean ice volume. The Southern Ocean ice pack is more sensitive to increases in precipitation.
For precipitation rates 1.5 times larger than the control ones, the annual mean snow, ice, and snow-ice volumes augment by
30, 20, and 180%, respectively. It is also found that the transfer to the ocean of as much as 50% of the precipitating snow
as a result of wind transport has almost negligible effects on the total ice volume. All the experiments exhibit a marked
geographical contrast in the ice-cover response, with a much larger sensitivity in the western sector of the Southern Ocean
than in the eastern sector. Our results suggest that snow-related processes are of secondary importance for determining the
sensitivity of the Arctic sea ice to environmental changes but that these processes could have an important part to play in
the response of the Antarctic sea-ice cover to future, or current, climatic changes.
Received: 30 June 1997/Accepted: 2 October 1998 相似文献
13.
It is demonstrated that during the whole annual cycle of ice cover evolution in 2006–2007 in the eastern seas of the Russian
Arctic and in the Arctic basin, the factors whose effect led to the formation of an extremely large anomaly of ice conditions
in summer 2007 were revealed. By the end of summer, the ice melted on the huge water area of 3500000 km2. In September, the ice edge between the meridians of 150° E-170° W reached the parallel of 85° N. The estimates of the open
water area being formed due to the ice melting and its drifting edge shift are given. 相似文献
14.
The performance of a snow cover model in capturing the ablation on the Greenland ice sheet is evaluated. This model allows an explicit calculation of the formation of melt water, of the fraction of melt water which re-freezes, and of runoff in the ablation region. The input climate variables to the snowpack model come from two climate models. While the higher resolution general circulation model (ECHAM 4), is closest to observations in its estimate of accumulation, it fails to give accurate results in its predictions of runoff, primarily in the southern half of the ice sheet. The two-dimensional low-resolution climate model (MIT 2D LO) produces estimates of runoff from the Greenland ice sheet within the range of uncertainty of the Inter governmental Panel on Climate Change (IPCC1) 1995 estimates. Both models reproduce some of the characteristics of the extent of the wet snow zone observed with satellite remote sensing; the MIT model is closer to observations in terms of areal extent and intensity of the melting in the southern half of the ice-sheet in July and August while the ECHAM model reproduces melting in the northern half of the ice sheet well. Changes in runoff from Greenland and Antarctica are often cited as one of the major concerns linked to anthropogenic changes in climate. Because it is based on physical principles and relies on the surface energy balance as input, the snow cover model can respond to the current climatic forcing as well as to future changes in climate on the century time scale without the limitations inherent in empirical parametrizations. For a reference climate scenario similar to the IPCC's IS92a, the model projects that the Greenland ice sheet does not contribute significantly to changes in the level of the ocean over the twenty-first century. Increases in accumulation over the central portion of the ice sheet offset most of the increase in melting and runoff, which takes place along the margins of the ice sheet. The range of uncertainty in the predictions of sea-level rise is estimated by repeating the calculation with the MIT model for seven climate change scenarios. The range is –0.5 to 1.7 cm. 相似文献
15.
Abstract This study reports on the implementation of an interactive mixed‐layer/thermodynamic‐ice lake model coupled with the Canadian Regional Climate Model (CRCM). For this application the CRCM, which uses a grid mesh of 45 km on a polar stereographic projection, 10 vertical levels, and a timestep of 15 min, is nested with the second generation Canadian General Circulation Model (GCM) simulated output. A numerical simulation of the climate of eastern North America, including the Laurentian Great Lakes, is then performed in order to evaluate the coupled model. The lakes are represented by a “mixed layer” model to simulate the evolution of the surface water temperature, and a thermodynamic ice model to simulate evolution of the ice cover. The mixed‐layer depth is allowed to vary spatially. Lake‐ice leads are parametrized as a function of ice thickness based on observations. Results from a 5‐year integration show that the coupled CRCM/lake model is capable of simulating the seasonal evolution of surface temperature and ice cover in the Great Lakes. When compared with lake climatology, the simulated mean surface water temperature agrees within 0.12°C on average. The seasonal evolution of the lake‐ice cover is realistic but the model tends to underestimate the monthly mean ice concentration on average. The simulated winter lake‐induced precipitation is also shown, and snow accumulation patterns on downwind shores of the lakes are found to be realistic when compared with observations. 相似文献
16.
Abstract The sensitivity of the annual cycle of ice cover in Baffin Bay to short‐wave radiation is investigated. The Princeton Ocean Model (POM) is used and is coupled with a multi‐category, dynamic‐thermodynamic sea‐ice model in which the surface energy balance governs the growth rates of ice of varying thickness. During spring and summer the short‐wave radiation flux dominates other surface heat fluxes and thus has the greatest effect on the ice melt. The sensitivity of model results to short‐wave radiation is tested using several, commonly used, shortwave parameterizations under climatological, as well as short‐term, atmospheric forcing. The focus of this paper is short‐term and annual variability. It is shown that simulated ice cover is sensitive to the short‐wave radiation formulation during the melting phase. For the Baffin Bay simulation, the differences in the resulting ice area and volume, integrated from May to November, can be as large as 45% and 70%, respectively. The parameterization of the effect of cloud cover on the short‐wave radiation can result in the sea‐ice area and volume changes reaching 20% and 30%, respectively. The variation of the cloud amount represents cloud data error, and has a relatively small effect (less then ±4%) on the simulated ice conditions. This is due to the fact that the effect of cloud cover on the short‐wave radiation flux is largely compensated for by its effect on the net near‐surface long‐wave radiation flux. 相似文献
17.
Inherent sea ice predictability in the rapidly changing Arctic environment of the Community Climate System Model, version 3 总被引：2，自引：1，他引：1
Seasonal predictions of Arctic sea ice have typically been based on statistical regression models or on results from ensemble ice model forecasts driven by historical atmospheric forcing. However, in the rapidly changing Arctic environment, the predictability characteristics of summer ice cover could undergo important transformations. Here global coupled climate model simulations are used to assess the inherent predictability of Arctic sea ice conditions on seasonal to interannual timescales within the Community Climate System Model, version 3. The role of preconditioning of the ice cover versus intrinsic variations in determining sea ice conditions is examined using ensemble experiments initialized in January with identical ice?Cocean?Cterrestrial conditions. Assessing the divergence among the ensemble members reveals that sea ice area exhibits potential predictability during the first summer and for winter conditions after a year. The ice area exhibits little potential predictability during the spring transition season. Comparing experiments initialized with different mean ice conditions indicates that ice area in a thicker sea ice regime generally exhibits higher potential predictability for a longer period of time. In a thinner sea ice regime, winter ice conditions provide little ice area predictive capability after approximately 1?year. In all regimes, ice thickness has high potential predictability for at least 2?years. 相似文献
18.
The Arctic’s rapidly shrinking sea ice cover: a research synthesis 总被引：21，自引：1，他引：20
Julienne C. Stroeve Mark C. Serreze Marika M. Holland Jennifer E. Kay James Malanik Andrew P. Barrett 《Climatic change》2012,110(3-4):1005-1027
The sequence of extreme September sea ice extent minima over the past decade suggests acceleration in the response of the Arctic sea ice cover to external forcing, hastening the ongoing transition towards a seasonally open Arctic Ocean. This reflects several mutually supporting processes. Because of the extensive open water in recent Septembers, ice cover in the following spring is increasingly dominated by thin, first-year ice (ice formed during the previous autumn and winter) that is vulnerable to melting out in summer. Thinner ice in spring in turn fosters a stronger summer ice-albedo feedback through earlier formation of open water areas. A thin ice cover is also more vulnerable to strong summer retreat under anomalous atmospheric forcing. Finally, general warming of the Arctic has reduced the likelihood of cold years that could bring about temporary recovery of the ice cover. Events leading to the September ice extent minima of recent years exemplify these processes. 相似文献
19.
K. P. Tyshko 《Russian Meteorology and Hydrology》2010,35(12):823-831
Main differences are considered in the formation of physical and mechanical ice properties in hummocky formations as compared
with level areas of the ice cover. The results of laboratory and field investigations demonstrate that these differences are
caused both by dynamometamorphic transformations of crystal ice structure as a result of the compression of ice fields before
the beginning of hummocky ice formation and in the process of consolidation of ice blocks within the ice hummocks formed during
the winter-spring period. 相似文献
20.
It is demonstrated within the frameworks of the analysis of determination methods of snowice cover reflectance that the problem
of the measurement technique of hummocky formation albedo has not been studied enough. The results of in situ experiments
carried out on the Arctic sea ice are presented. The results of ice hummock albedo measurements using different techniques
are discussed. The need to organize the special experimental research for the development of practical recommendations for
estimating the hummocky formation albedo is declared. 相似文献