Variability and climate sensitivity of fast ice extent in the north-eastern Kara Sea   总被引：1，自引：0，他引：1  

Dmitry Divine  Reinert Korsnes  Alexander Makshtas 《Polar research》2003,22(1):27-34

This work investigates the temporal and spatial variation of shore-fast ice extent in the north-eastern part of the Kara Sea during 1953-1990 and its sensitivity to interannual variability of the regional climate. The area of fast ice in spring months shows a bimodal distribution. This indicates the existence of two different regimes of fast ice formation driven by the system of prevailing winds. The westward wind transport during the cold season gives larger fast ice extent while the eastward wind transport suppresses the expansion of fast ice. There is a significant correlation (ca. −0.55) between the average winter temperature and the area of fast ice. Linear trends for time records of shore-fast ice area in spring show a decrease during 1953-1990. This decrease is most pronounced in April: the mean fast ice area in April is 12% lower in 1988-1990 compared to 1953-55. A comparison of fast ice regimes for two particular years–1979 and 1985–revealed a significant influence of cyclone activity on fast ice development over the course of the cold season. It is shown that partial break-ups of fast ice in spring 1985 are associated with the passage of cyclones across the area of fast ice.  相似文献   

Methane concentration in the atmospheric boundary layer from the measurements at north pole-36 and north pole-39 drifting ice stations     

A. P. Nagurnyi  A. P. Makshtas 《Russian Meteorology and Hydrology》2016,41(3):199-204

Episodic emissions ofmethane with the concentration of4 ppm to the lower atmosphere near the continental slope of the Arctic Ocean are considered. It is revealed that such methane emissions can be associated with the erosion of sediments containing gas hydrates, for example, as a result of the effects of mudflows caused by the instability of slope currents as well as by the geologic activity in the zone of significant depth drops. The high background concentration of methane is registered in the central part of the Arctic Ocean that is probably provoked by biologic activity within sea ice and on its bottom.  相似文献   

Low-Level Atmospheric Jets And Inversions Over The Western Weddell Sea   总被引：6，自引：1，他引：5  

Edgar L Andreas  Kerry J. Claffy  Aleksandr P. Makshtas 《Boundary-Layer Meteorology》2000,97(3):459-486

For four months in the fall and earlywinter of 1992, as Ice Station Weddell (ISW) driftednorthward through the ice-covered western Weddell Sea,ice station personnel profiled the atmosphericboundary layer (ABL) with radiosondes. These showedthat the ABL was virtually always stably stratifiedduring this season: 96% of the soundings found anear-surface inversion layer. Forty-four percent ofthese inversions were surface-based. Eighty percentof the soundings that yielded unambiguous windprofiles showed an atmospheric jet with speeds as highas 14 m s^-1 in a core below an altitude of 425 m. This paper documents the features of these inversionsand low-level jets. Because the inversion statistics,in particular, are like those reported in and aroundthe Arctic Ocean, similar local processes seem tocontrol the ABL over sea ice regions in bothhemispheres. A simple two-layer model, in which anelevated layer becomes frictionally decoupled from thesurface, does well in explaining the ISW jetstatistics. This model also implies a new geostrophicdrag parameterization for sea-ice regions that dependson the magnitude of the geostrophic wind, the 10-mdrag coefficient C_DN10, and the ABL height, butnot explicitly on any stratification parameter.  相似文献   

Parameterizing turbulent exchange over sea ice: the ice station weddell results   总被引：1，自引：0，他引：1  

Edgar L Andreas  Rachel E. Jordan  Aleksandar P. Makshtas 《Boundary-Layer Meteorology》2005,114(2):439-460

A 4-month deployment on Ice Station Weddell (ISW) in the western Weddell Sea yielded over 2000 h of nearly continuous surface-level meteorological data, including eddy-covariance measurements of the turbulent surface fluxes of momentum, and sensible and latent heat. Those data lead to a new parameterization for the roughness length for wind speed, z₀, for snow-covered sea ice that combines three regimes: an aerodynamically smooth regime, a high-wind saltation regime, and an intermediate regime between these two extremes where the macroscale or `permanent' roughness of the snow and ice determines z₀. Roughness lengths for temperature, z_T, computed from this data set corroborate the theoretical model that Andreas published in 1987. Roughness lengths for humidity,z_Q, do not support this model as conclusively but are all, on average, within an order of magnitude of its predictions. Only rarely arez_Tand z_Q equal to z₀. These parameterizations have implications for models that treat the atmosphere-ice-ocean system.  相似文献   

Sea ice growth at nonstationary ocean-atmosphere heat exchange     

P. V. Bogorodskii  A. P. Makshtas  A. V. Pnyshkov 《Oceanology》2009,49(3):330-337

A thermodynamic model of sea snow-ice cover growth under the influence of heat flows on its upper and lower surfaces is presented. The growing is described with an extended region of phase transition (a two-phase region) with a linear temperature distribution. The temperature of the upper surface is calculated with the use of a heat-balance equation on the basis of determinable meteorological observation data. The comparison of the model results with freezing experimental data is performed.  相似文献   

Cloud Radiative Forcing over Sea Ice in the Arctic during the Polar Night According to North Pole-37, -39, and -40 Drifting Stations     

Makhotina  I. A.  Chechin  D. G.  Makshtas  A. P. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(5):451-460

Izvestiya, Atmospheric and Oceanic Physics - In the paper, we present the results of an analysis of ceilometer measurements at North Pole (NP) drifting station 37, 39, and 40. The frequencies of...  相似文献   

Brewer,SAOZ and Ozonesonde Observations in Siberia     

V. Dorokhov  V. Yushkov  A. Makshtas  G. Ivlev  N. Tereb  V. Savinykh 《大气与海洋》2015,53(1):14-18

Abstract

Regular ground-based measurements of total ozone are available over the full Russian territory using M-124 filter ozonometers, Brewer spectrophotometers, and Système d'Analyse par Observation Zénithale (SAOZ) spectrometers in the Arctic region where these observations are essential for evaluating ozone loss in winter. Daily measurements are performed by three Brewer spectrophotometers; these are located in Kislovodsk (43.7°N, 42.7°E), Obninsk (55.1°N, 36.6°E), and Tomsk (56.5°N, 85.1°E). Two SAOZ spectrometers are deployed at the Arctic Circle in Salekhard (66.5°N, 66.7°E) and Zhigansk (66.8°N, 123.4°E). In addition, regular winter–spring ozonesonde soundings are carried out in Salekhard. Altogether, they have provided the unique measurements over the eastern Arctic required for characterizing ozone loss during each winter and will also monitor the anticipated ozone recovery following the reduction of chlorine and bromine ozone-depleting substances in the atmosphere.  相似文献