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MODERN ENVIRONMENTAL GEOGHEMICAL CHARAC-TERISTICS IN THE GREAT WALL STATION REGION 1990, 2 (2):  1-12.  Abstract ( 1795 )   PDF (867KB) ( 1154 )   The study of the geochemical characteristics of the modern environment is to reveal the different chemical composition and internal relationship among various elements in the cpigenetic environment as well as the influence of anthropogenic activity on it. The chemical constituents of all elements in the natural environment are complicated and the geochemical process going on in the epigenetic environment is a grand and complex process in the exchange of matter and energy running through all of them. The transference process of the chemical elements going on in the epigenetic environment at the same time also refers to their geochemical time- and space-differential processes in same. It is exactly because of the going on of such processes that obvious differentiation takes place in the interior of the epigenetic environment and link together the various differentiated components genetically to form a unified epigenetic environmental integral. Only by means of making an integrated study of all the environmental elements overally that it is possible to make clear the geochemical essentials in them. 1. Modern environmental geochemical characteristics and natural environmental evolution have an inherent relationship. To know the geochemical characteristics of ,the modern environment and its laws of variation not only calls for an overall consideration of the features of the modern regional environment and the various geochemical properties of the environmental factors and their interaction but also the dynamic changes and phasing of the natural environment. It is only through gaining a deeper knowledge of the geochemical characteristics of the modern environment that it is possible to strike up the geochemical relation among all the environmental factors and apply it to the study of the evolution of the natural environment 2. The background value of environmental geochemistry is the function of time. The level of its content and the law of its variation not only reflect the build-in attribute of the environmental medium but is also identical with the phasing of the dynamic variation of the environment. 3. A comparison of the products of epigenetic and endogenic action shows that regional characteristics of the former are marked. The environmental geochemical characteristics of this region when compared with other regions reveals not only similarity but also peculiarity. The constitution of the chemical elements of pyrogenic and sedimentary rocks here have obvious similarities. The element content of pedogenic mother rocks have marked constraint on primitive soil; but the correlationship of both is not very prominent. However, elements As in pyrogenic rocks and Cu in sedimentary rocks respectively are correlated to certain sulphophilic elements in the primitive soil developed on them. 4. The difference in chemical constitution and content level of atmospheric precipitation of this region are conspicuous with a display of instability; whereas the chemical co-nstitu tion and content of surface water are relatively stable. 5. The atmospheric aerosol of this region manifests itself to be clearly of the "oceanic type". Approximately more than 80 %. of these have the ocean as their generation source; roughly 10% are developed from the local soil source and another 10 % or so come from remote continents through long distance transmission which reflects from one facet the intensity of the global impact of human activity. 6. In the soil nearby the research station region, the content of Pb and Cd have increased conspicuously. This is primarily caused by exhausts discharged from electric generation units, automobiles and aeroplanes. Related Articles | Metrics

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STRATIGRAPHIC STUDIES OF THE SNOW AND THE PROCESS OF THE ICE FORMATION ON NELSON ICE CAP, ANTARCTICA 1990, 2 (2):  13-21.  Abstract ( 1784 )   PDF (669KB) ( 1078 )   The Nelson Ice Cap is a polar-maritime glacier. The development of snow and firn depends on wet metamorphic process under the effect of melting water infiltration-freezing. The velocity of densification process of snow depends on temperature condition, the amount of the melting water and itself physical characteristics. The process of densification appears in the form of homogenization and little change. The differences in climatic condition and amount of melting water cause differences in time, depth and shapes of the ice formation. The depth of the ice formation is about 23 to 25 m, and the time 17 to 19 years. Zones of the ice formation can be distinguished as warm infiltration-recrystallization, infiltration-congelation and ablation zones. The disrtibution of these zones is apparently influenced by climatic variation. Related Articles | Metrics

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TEMPERATURE REGIME OF THE GLACIERS IN THE NEIGHBOURHOOD OF GREAT WALL STATION, ANTARCTICA 1990, 2 (2):  22-27.  Abstract ( 1972 )   PDF (274KB) ( 1260 )   In the Southern Hemisphere summer of 1985-1986, several shallow boreholes (mostly 10 m and deeper) were drilled on the glaciers in Nelson Island and King George Island, which are near the Great Wall Station, Antarctica. Temperature measurement in them and analysis show that temperature at 10 m depth is a little lower than -1℃ in the abla tion area and close to or at 0C in the accumulation area except in the central part of King George Island Ice Gap, where elevation is about 680 m and temperature at 10 m is estima ted to be around -5℃. Based on the estimates of temperature distribution in the active layer or the near-surface layer, temperature regime of the deep layer is discussed qualitatively. The author concludes that temperature regime of the glaciers in this region is very different than that in the cold glaciers of the higher latitudes but it is not the same as in the temperate glaciers of the lower latitudes. The glaciers in this region are mostly temperate. However,if the altitude is higher such as in the central part of King George Island Ice Cap, the ice will become cold and is frozen to the bed because temperature in the active layer is lower due to decrease in air temperature and surface melting with increasing elevation, and ice thickness is not large. Related Articles | Metrics

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ALGAE FOSSILS IN SEDIMENTS OF WEST LAKE ON FILDES PENINSULA OF KING GEORGE ISLAND, ANTARCTICA, AND THE ENVIRONMENTAL EVOLUTION 1990, 2 (2):  28-35.  Abstract ( 1789 )   PDF (2272KB) ( 1352 )   A large amount of Pediastrum and Bacillariophyta fossils were found in sediments of West Lake on Fieldes Peninsula of King George Island. Pediastrum fossils include the following species: Pediastrum Mey., P. boryanum (Turp.), P. simplex (Mey.) Lemm., P. duplex Mey., and Bacillariophta fossils include Melosira Ag., M. roeseana Rabh., M. roeseana var., Achnanthes Bory., A. lanceolata Breb., A. lanceolate, var. rostrata Hust., A. exigua var. heteroval-vata Krasske, A. delicatla (Ktz.) Grun., Navicula. Bory., N,dicephala (Ehr.) W.S., N. pseudos-cutiformis Hust., N., cuspidata Kutz., N. cryptocephala Kutz., N. anglica Ralfs, N. rhynchocephala Kutz., Stauroneis Ehr., S. anceps Ehr., S. anceps f. linearis (Ehr.) CI., Pinnularia Ehr., P. gibba var. subundulata Mayer, P. borealis Ehr., P. gibba var. linearis Hust., P. brevicostata CI., P. intermpta W. Smith, P. undulata Greg., P. microslauron (Ehr.) CI., Gomphonema Ag., G. angustatum (Kutz.) G. angustatum var. obtusatum V.H., G. parvulum var. micropus (Ktz.) Cleve., G. parvulum var. subelliptica CI., G. abbreviatum Ag., Hantzschia Grun., Surirelia Turp., Mtzschia frustulum (Ktz.) Grum., N. linearis W. Smith, Hantzschia amphioxys var. maior Grum., Synedra rumpens Ktz., pephora marty He'rib. and etc. The distribution and content variation of the fossils along the sedimentary profile permit us to reach the following conclusions: about 3600 a. B.P., this area was covered with glaciers,because no algae fossils were discovered in this part of section at about 264-289cm depth; From 3600 to 3000 a B.P. it was dominated by a shallow periglacial lake, a few Pediastrum fossils were found in this part of section (a depth from 289 cm to 224 cm); And from 3000 to 1200 a B.P., the lake became deeper gradually and the climatic conditions were better, because a large amount of Pediastrum and Bacillariophyta fossils were found in this part of section (from 224 ot 87 cm) and these Algaes lived in fresh water; And from 1200 a B.P. to the present (from 87 cm depth of the section to the surface layer of the lake) the content of the fossils some varies. It shows that the lake level has fluctuated slightly. Related Articles | Metrics

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A STUDY ON THE COMPOSITION OF ATMOSPHERIC AEROSOL OVER THE GREAT WALL STATION, ANTARCTICA 1990, 2 (2):  36-43.  Abstract ( 1831 )   PDF (507KB) ( 1025 )   Atmospheric pollution is not only directly harmful to human health at source region but it also be transported through the atmosphere over great distances. Atmospheric particles, especially submicron aerosol particles which have long atmospheric residence times have led to the contamination of many non-urban areas. Baseline atmosphericumcasure-ments should help us make clear the source, dispersion, concentrations, degree of transportation and enrichment factors of these pollutants. The Antarctica area offers one of the best locations on the Earth for studing the composition of the background aerosol since it is isolated both geographically and meteorologically from the major souices of anthropo-gentric emission. The aerosol samples were collected by cascade impactors designed and constructed by our Res. Center. Each sample provided eight particle size fractions in the normal aerody namic diameters (μm) ranges. From first stage to the 7th stage Mylar film in 3μm thickness was used, Nuclepore film with 0.40μm of pore diameter was used in the last stage. The samples were collected at flow of two liters per minute. The samples were analysed by Proton Induced X-ray Emission (PIXE) method. The X-ray spectra were analysed by computer, with small peaks being checked by manual integration to obtained the final con centrations. The data are given in μg per standard cubic meter. In order to learn the enrichment factors of various elements the results were separated to two groups: coarse and fine particles. Coarse mode (>10μm) concentrations were compared with the composition of the earth's crust. The fine mode of elements show large relative enrichments. Authors have compared to those recently measured results at some other locations. It was also showed the aerosol results measured in Antarctica by a part of authors. It can be concluded that the Antarctica is a good background area on the Earth. The measurements of atmospheric chemical composition, are valuable in order to establish concentration baselines with which polluted air may be compared. They also give an opportunity to investigate the physical and chemical characteristics of the atmosphere withont complicating anthropological influences. Related Articles | Metrics

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STUDY ON ATMOSPHERIC AEROSOL OVER GREAT WALL STATION DURING AUSTRAL SUMMER, 1987 1990, 2 (2):  44-50.  Abstract ( 2049 )   PDF (520KB) ( 1059 )   The atmospheric aerosol samples have been taken by a 8-stage cascade impactor sampler over the Antarctic Great Wall Station during Jan. 8 to Feb. 19, 1987. the PIXE analysis was carried out on the 1.7×2 MV tandem accelerator at Beijing Normal University in november of 1987. As a result, the size distribution of mass concentration of 18 elements was obtained. The enrichment factors of various elements in the atmospheric aerosol re lative to the earth crust and the sea water with the salinity 35.0‰ were calculated. The en richment factors of the element Mn, Fe, Si, Ti and Pb arc approximate to 1 relative to the earth crust, thus it indicates that these elements mainly come from soil, the common charac teristic of size distribution is that the concentrations increase after larger than 8Um the enrichment factors of the element K,Ca,Cl,S, Sr, and Br are approximate to 1 relative to the sea water, which indicates that these element mainly come from the marine aerosol, they mainly distribute in the range of 1-8μm; the enrichment factor of various elements on the stage 0 (particle size less than 0.25μm) relatively grow larger, which means that the contri bution of anthropogenic, pollution become larger. According to the analyzing on the characteristic of size distribution of the aerosol mass concentration over the Antarctic Great Wall Station we suggest that the anthropogenic comtaminants of super-fine size are mainly transmitted from the other distant coninents. Related Articles | Metrics

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EXPERIMENT AND RESEARCH ON THE NIGHTTIME MODE OF VLF SIGNALS ON ANTARCTICA 1990, 2 (2):  51-60.  Abstract ( 1898 )   PDF (734KB) ( 1098 )   When the VLF signals from the stations located in the area of middle or low latitudes are travelling across the equator along the direction from northeast to southwest or from southeast to northwest,the TE wave is present by the coupling effect of the geomagnetic field Basing on the VLF phase observation in Antarctica, it is found that the TE, mode becomes the dominant mode during night time in the propagation direction from northeast to southwest at a long distance, and that for GBR signal(16 kHz)tho mode conversion interference produces a cycle slip during the sunrise transition at a distance of 13660.7 km far away from the transmitter. In this case, the mode conversion coefficient from the TM, mode into the TE, mode during the sunrise transition is estimated to be 0.28. The average depths of the diurnal phase variation trapezium of the 10.2 kHz signals from the stations B, C and D of the Omega navigation system are 135 μs, 138μs and 140 μs respectively. If only TM, mode was present during both day and night times, the calcu- lated values of the depths of the phase trapezium should be 97.4μs, 135μs and 137.6μs respectively. For the 10.2 kHz signal from the station B in the direction from northeast to southwest. If the TE, mode is dominant during nighttime at the receiver site, the calcula ted values of the depth of the phase trapezoid should be about 141.7Us, which is agreed basi cally with the measured value. Because the receiver is located in the polar region, the measured value is slightly less than the calculated value. For the diurnal phase variations of the 10.2 kHz signals from the stations G and E observed at the Xinxiang, It is found that the situation is similar. For the 10.2 kHz signals from the station G travelling across the equator along the direction from southeast to northwest, the TE, mode becomes dominant during the night time at the receiver site, Xinxiang. The calculated value of the depth of the phase trapezoid is about 147.6 us, which is agreed well with the measured value of 151 us. When the 16kHz signals from the station GBR was observed at the Great Wall Station Antarctica, the diurnal phase variation curves exhibits a notable interference pattern during the sunrise transition, sometimes the interference even could be so serious that a whole cycle slip was caused. For the reason of which we can explain from the following five aspects: (1) The period of mode conversion interference △t. (2) The distance from the sunrise line to the site where the first amplitude interference minimum occured. (3) The composition of the phase vector. (4) The calculation of the condition |E2|>|E1|. (5) The calculated values of the interference phase deviation θ and the amplitude ratio of the TEi and TMt modes |E2| / |E1|, resulted from the observed curves during 6 days successively. To sum up, the diurnal phase variation curves exhibit a notable mode conversion inter-ferencer pattern due to the interference between the quasi-TE1 mode and the quasi-TM1 mode during the sunrise transition, occasionally the interference causes a whole cycle slip. Under the condition, the mode conversion coefficient from the TM1 mode into theTE, mode during the sunrise transition is estimated to be 0.28. Related Articles | Metrics

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STRATOSPHERIC SUDDEN WARMING AND ITS RELATIONSHIP WITH OZONE ON ANTARCTICA IN AUGUST, 1988 1990, 2 (2):  61-66.  Abstract ( 1716 )   PDF (2423KB) ( 1109 )   An attempt was made to study the stratospheric sudden warming on Antarctica in August, 1988. In this paper, the variations in total ozone, 30hPa temperature, 30hPa 24-hour temperature change and westly wind are given by using a processing of original data provided by Japanese Antarctic Research Expedition 29 (JARE29). From the preliminary analysis, it's obvious that a sudden warming occurs in lower stratosphere over Syowa Station, in which the 30hPa temperature increases by 40.9℃, from-71.1℃ to-30.2℃, in the period of August 26-30, and maximum 24-hour warming reaches 21.7℃/day. From correlation analysis, good correlations between 30hPa temperature, 30hPa westly wind and total ozone in this sudden warming period are found. In the period of Aug. 15-Sep. 6, 1988, the correlation coefficient of 30 hPa temperature is 0.96 with total ozone and 0.88 with 30 hPa westly wind. This result is very close to that former authors got. In ordor to study the ozone heating role in this sudden warming, the correlation between 30hPa 24-hour temperature variation and total ozone is studied. The correlation is quite different from that between 30 hPa temperature and total ozone. The high correlation coefficient disappears. It's only about 0.03. But during August 15-Sep. 6, the correlation coefficient between 4-day delayed total ozone and 30hPa temperature variation looks to be high, reaching 0.64. This fact means that the ozone heating effect is not the cause of the sudden warming in this period. The ozone variation is only caused by the fluctuation of circulation due to the sudden warming. In order to study the other cause of the sudden warming, for the transfer of planetary-wave enegy, a correlation between the all-layer westly wind speed and sohPa warming is analysed. It can be found that the all-layer westly wind occurs on about August 22,1988, 5-day before the date of the sudden warming. According to the theory of planetary wave, all-layer westly wind supplies the situation for planetary wave in troposphere transferring to stratosphere. The transferring planetary wave energy causes the sudden warming. Therefore, the all-layer westly wind may shows a possibility that the direct cause for this sudden warming is upward transfer of planetary wave in troposphere. Because there is not grided data used in this paper, the further research should be needed to prove the effect of the upward transferring planetary wave on the sudden warming in the stratosphere of Antarctica. Related Articles | Metrics

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A REVIEW ON THE STUDY OF ANTARCTIC OZONE HOLE 1990, 2 (2):  67-80.  Abstract ( 1783 )   PDF (848KB) ( 964 )   Since Farman et al. (1985) reported firstly the ozone depletion in the spring over An- tarctica, A great deal of research efforts has focussed on this unexpected phenomenon. The Antarctic ozone depletion occured in almost every springtime simce the earlier 1980s (Fig. 1), and maintains for about one month (Fig. 2). It reached its maximum and minimum in 1987 and 1988 respectively (Fig. 3). The height of ozone depletion is in the lower stratosphere about 10-22 km (Fig. 4). Based on the available literature on Antarctic ozone hole published, three interpretations on the ozone depletion are reviewed in this paper. (1) ATMOSPHERIC DYNAMICS In the winter when the sun does not shine directly on the southern hemisphere, the atmosphere over Antarctica cools by emission of longwave radiation and forms a circumpolar vortex. On the other hand, the activity of planetary wave from the southern hemisphere is weak which hardly transports heat, momentum and mass from middle latitudes to polar region. When the sunshine appears again over the Antarctic in the earlier springtime, the increasing diabat heating by the sun makes the air move upward, and carris the air with lower abundance of ozone in the troposphere into the stratosphere, resulting in the total ozone depletion. In the spring, the circumpolar vortex is brokendown by the final wrarming resulted from the increasing planetary wave activity from the southern hemisphere. Meanwhile, the mid-latitude air with high abundance of ozone flows rapidly onto Antarctica and results in increase of total ozone. In res-cent years the aerosol on Antarctica, which can absorb the solar radiation directly increased with the eruption of the volcanoes, and led the upwelling current to become stronger than ever before. A lot of observational facts shows that the temperature in the tratosphere over Antarctica also have decreased in the rescent years, there may be some relationships between these two phenomena (Fig. 5). (2) SOLAR ACTIVITY Yoshiro (1986) found that the year to year change in the three-year runnsng means of total ozone also has the same 11-year returning period as that of the wolf Sunspot number (Fig. 6). As the coming of the high solar activities, the concerntration of NO2 and odd nitrigen in the air increases which may play an role in appearence of the Antarctic ozone hole. (3) ANTHROPOGENIC ACTIVITIES Some of the authors suggested that the main cause for appearence of the ozone hole should be the increasing chlorine in the atmosphere which resulted from the solution of the man-made chloronuorocarbons by violet solar radiation. Solomon and others. (1986) and McElroy and others (1986a) concluded that large ozone decrease could occur at lower altitudes if most of the available total chlorine were in the reactive form of chlorine radical, or Clox. They suggested that total ozone variation might occur if the heterogeneous reactions (11) or (12) proceeded rapidly on the surface of polar stratospheric clouds (PSCs) which are frequently present in the Antarctic winter and spring. Solomon and his co-workers (1986) suggested that the loss of ozone might proceed at lower altitudes via the catalytic cycle (l3)-(16). EcElroy and others (1986a) emphasized the importance of synergy between bromine and chlorine that would exist under such conditions. In particular, the net reactions (17) - (19), as indicated by Molina and Molina (1986) in their studies of the Gl2O2 dimer chemistry, can proceed via the reaction (20) and subsequently destroyed by the cycle (21) - (23) or (23) - (26). The models suggest that about 75% of the computed ozone removal is associated with reactions involving the ClO dimer, and about 25% may be a reaction sequence involving ClO and BrO. The obtained results of studies on the Antarctic ozone hole till now indicate that the process of the formation and close of the ozone hole might be as follows. In the Antarctic winter, on the one hand, the planetary wave from the southern hemisphere acts weakly, which almost could not transport heat, momentum and mass to the antarctic Related Articles | Metrics

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SEISMOLOGICAL OBSERVATION AT THE GREAT WALL STATION DURING AUSTRAL WINTER OF 1986 1990, 2 (2):  81-85.  Abstract ( 2213 )   PDF (1085KB) ( 1079 )       The seismological observation has been made on seimographs at the Great Wall Station during the period of 271 days from March 30 to October 25,1986. Total more than 3000 seismic events were recorded, most of them are microseisms generated by breaking and fracture of ice layers, 4 are the shallow earthquakes in sea near South Shetland Islands, a M=8.1 earthquake occurred at Aleutan Islands on May 7,1986, and a M=6.4 earthquake occurred at South Sandwish Islands on April 14,1986.     There is a significant difference between icequake and tectonic earthquake. The seimic records on Nov.16,1986, provide an excellent case for distinguishing icequake from tectonic earthquake. The icequake is characterized by a sharp first motion, high frequency and rapid attenuation. So it is easy to distinguish the icequake from the tectonic earthquake by their first motions and waveforms. References | Related Articles | Metrics