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1.
Three ship-based observational campaigns were conducted to survey sea ice and snow in Prydz Bay and the surrounding waters(64.40°S–69.40°S, 76.11°E–81.29°E) from 28 November 2012 to 3 February 2013. In this paper, we present the sea ice extent and its variation, and the ice and snow thickness distributions and their variations with time in the observed zone. In the pack ice zone, the southern edge of the pack ice changed little, whereas the northern edge retreated significantly during the two earlier observation periods. Compared with the pack ice, the fast ice exhibited a significantly slower variation in extent with its northernmost edge retreating southwards by 6.7 km at a rate of 0.37 km?d-1. Generally, ice showed an increment in thickness with increasing latitude from the end of November to the middle of December. Ice and snow thickness followed an approximate normal distribution during the two earlier observations(79.7±28.9 cm, 79.1±19.1 cm for ice thickness, and 11.6±6.1 cm, 9.6±3.4 cm for snow thickness, respectively), and the distribution tended to be more concentrated in mid-December than in late November. The expected value of ice thickness decreased by 0.6 cm, whereas that of snow thickness decreased by 2 cm from 28 November to 18 December 2012. Ice thickness distribution showed no obvious regularity between 31 January and 3 February, 2013. 相似文献
2.
Problem on development control of marine source bed hold in Chinese petroleum industry progression. The Hongshuizhuang Formation,Tieling Formation and Xiamaling Formation in the Middle and Upper Proterozoic are important hydrocarbon source beds in northern North China, and investigation of their sedimentary environments and the controls has great significance for petroleum exploration in North China. Based on sedimentology (sequence stratigraphy), palaeoecology, sedimentary geochemistry, and sedimentary palaeogeography, their development pattern is discussed. All these studies indicate that the development controls of the hydrocarbon source beds include a favorite palaeogeographic location, exceeding propagation of biomes in low and middle latitudes, anoxic environments, enrichment of phosphorus element and the adsorption of clay minerals during the preservation of organic matter in the marine carbonates. 相似文献
3.
DONG Yunpeng ZHANG Guowei ZHAO Xia YAO Anping & LIU Xiaoming The Key Laboratory of Continental Dynamics Ministry of Education Department of Geology Northwest University Xi抋n China 《中国科学D辑(英文版)》2004,(4)
Being a composite collisional orogen between North China and South China blocks, the Qinling orogenic belt is the key to understand the composite combination, prolonged evolutionary history and their continental dynamics. The main suture between north and south Qinling, called Shangdan suture zone (SDSZ), had been studied in detail for about twenty years. Recently, another suture zone, called Mianl黣 suture zone (MLSZ), has been identified in the Qinling Mountains. It is characterized b… 相似文献
4.
The ice algal and phytoplankton assemblages were studied from Nella Fjord near Zhongshan Station, East Antarctica from April 12 to December 30, 1992. Algal blooms occurred about 3 cm thick on the bottom of sea ice in late April and mid November to early December respectively, and a phytoplankton bloom appeared in the underlying surface water in mid December following the spring ice algal bloom. The biomass in ice bottom was 1 to 3 orders of magnitude higher than that of surface water. Amphiprora kjellmanii, Berkeleya sp., Navicula glaciei, Nitzschia barkelyi, N. cylindrus /N. curta, N. lecointei and Nitzschia sp. were common in the sea ice temporarily or throughout the study period. The biomass in a certain ice segment was decreased gradually and the dominant species were usually succeeded as the season went on. Nitzschia sublineata and Dactyliosolen antarctica were two seasonal dominant species only observed in underlying water column. The assemblages between bottom of ice and underlying surface water were different except when spring ice algae bloomed. The evidence shows that the ice algal blooms occurred mainly by in situ growth of ice algae, and the phytoplankton bloom was mostly caused by the release of ice algae. 相似文献
5.
6.
Based on the observed and NCEP reanalysis data from 1985 to 2006,the climate background and synoptic situation of fog at Great Wall Station were analyzed. It is shown that the seasonal variation of fog is controlled by the change of general circulation and local pressure field. Three favorable typical synoptic situations for fog development are found, the Front-of-A-Depression type, the Saddle-Shaped-Field type and the Passing-Weak-Cyclone type. The first one is the most important situation. Advection cooling fog is dominant at Great Wall Station, but there are other kinds of fog as well. As a result, some helpful principles for local fog forecasting are given. 相似文献
7.
YUAN LinWang YU ZhaoYuan XIE ZhiRen SONG ZhiYao & Lü GuoNian School of Geographical Science Nanjing Normal University Nanjing China 《中国科学D辑(英文版)》2009,(6)
Sea-level is closely linked to the Earth's climate and its change is important as a metric for global and regional climate change. Identifying, extracting, and revealing such information through detailed analysis is the prerequisite for understanding the mechanisms of sea-level change. The monthlyaverage tide-change records reported and examined in this paper are from 10 tide gauge stations distributed in the northwest margin of the Pacific Ocean, registered during the period 1965-2005. In particular, we ha... 相似文献
8.
Seong-JoongKim Hye-Sun Choi Baek-Min Kim Sang-Jong Park Taehyoun Shim Joo-Hong Kim 《极地研究(英文版)》2013,(4):326-338
This study investigates recent climate change over the Arctic and its link to the mid-latitudes using the ERA-Interim global atmospheric reanalysis data from the European Center for Medium-Range Weather Forecast (ECMWF). Since 1979, sub- stantial surface warming, associated with the increase in anthropogenic greenhouse gases, has occurred over the Arctic. The great- est warming in winter has taken place offshore in the Kara-Barents Sea, and is associated with the increase in turbulent heat fluxes from the marginal ice zone. In contrast to the marked warming over the Arctic Ocean in winter, substantial cooling appears over Siberia and eastern Asia, linked to the reduction of Arctic sea ice during the freezing season (September-March). However, in summer, very little change is observed in surface air temperature over the Arctic because increased radiative heat melts the sea ice and the amount of turbulent heat gain from the ocean is relatively small. The heat stored in the upper ocean mixed layer in summer with the opening of the Arctic Ocean is released back to the atmosphere as turbulent heat fluxes during the autumn and through to the following spring. This warming of the Arctic and the reduced sea ice amplifies surface cooling over Siberia and eastern Asia in winter. 相似文献
9.
10.
Reconstruction of paleocoastlines for the northwestern South China Sea since the Last Glacial Maximum 总被引:1,自引:0,他引:1
The range of relative sea level rise in the northwestern South China Sea since the Last Glacial Maximum was over 100 m. As
a result, lowland regions including the Northeast Vietnam coast, Beibu Gulf, and South China coast experienced an evolution
from land to sea. Based on the principle of reconstructing paleogeography and using recent digital elevation model, relative
sea level curves, and sediment accumulation data, this paper presents a series of paleogeographic scenarios back to 20 cal.
ka BP for the northwestern South China Sea. The scenarios demonstrate the entire process of coastline changes for the area
of interest. During the late glacial period from 20 to 15 cal. ka BP, coastline slowly retreated, causing a land loss of only
1×104 km2, and thus the land-sea distribution remained nearly unchanged. Later in 15–10 cal. ka BP coastline rapidly retreated and
area of land loss was up to 24×104km2, causing lowlands around Northeast Vietnam and South China soon to be underwater. Coastline retreat continued quite rapidly
during the early Holocene. From 10 to 6 cal. ka BP land area had decreased by 9×104km2, and during that process the Qiongzhou Strait completely opened up. Since the mid Holocene, main controls on coastline change
are from vertical crustal movements and sedimentation. Transgression was surpassed by regression, resulting in a land accretion
of about 10×104km2.
Supported by Key Laboratory of Marginal Sea Geology, Chinese Academy of Sciences (Grant No. MSGL0711), the Guangdong Natural
Science Foundation (Grant No. 04001309) and Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy
of Sciences (Grant No. MGE2007KG04) 相似文献