The pigmental composition and the absorption spectral analysis of Ulothrix sp．and benthic diatoms in the intertidal zone of Great Wall Station，Antarctica

This paper reports the results of the absorption spectral analysis of Ulothrix sp. attached to the rocks from the intertidal zone in front of Great Wall Station,Antarctica in February 1989,and the benthic diatoms growing on small stones and on the edge of swamps of that zone.Six kinds of pigments were separated and identified in benthic diatoms.They are carotene, chlorophyll-a, fucoxanthin, chlorophyin, neoxanthin and chlorophyll-c. Nine kinds of pigments were identified in Ulothrix sp.. They are carotinoid, pheophytin, chlorophyll-a, -b, chlorophyllin, chlorophyllide-a, neoxanthin, chlorophyll-c and pheophytin-c. The intertidal benthic diatoms and Ulothrix sp. have specific absorption spectra and there are also marked differences in the composition of algal pigments they contain. Since the pigments of marine algae show differences in their absorption spectra, the absorption spectrum can be used to identify the species of marine algae.

Towards More Snow Days in Summer since 2001 at the Great Wall Station,Antarctic Peninsula:The Role of the Amundsen Sea Low

The variation in the precipitation phase in polar regions represents an important indicator of climate change and variability.We studied the precipitation phase at the Great Wall Station and Antarctic Peninsula(AP)region,based on daily precipitation,synoptic records and ERA-Interim data during the austral summers of 1985?2014.Overall,there was no trend in the total precipitation amount or days,but the phase of summer precipitation(rainfall days versus snowfall days)showed opposite trends before and after 2001 at the AP.The total summer rain days/snow days increased/decreased during 1985?2001 and significantly decreased at a rate of?14.13 d(10 yr)?1/increased at a rate of 14.31 d(10 yr)?1 during 2001?2014,agreeing well with corresponding variations in the surface air temperature.Further,we found that the longitudinal location of the Amundsen Sea low(ASL)should account for the change in the precipitation phase since 2001,as it has shown a westward drift after 2001[?41.1°(10 yr)?1],leading to stronger cold southerly winds,colder water vapor flux,and more snow over the AP region during summertime.This study points out a supplementary factor for the climate variation on the AP.

Concentration level of heavy metals in the Great Wall Bay， Antarctica in austral summer

Heavy metals in different marine environmental mediums from the Great Wall Bay, Antarctica were determined. Sea water samples from 14 stations, surface sediments from 2 stations and marine organisms from 1 station were analyzed for Cu, Pb, Zn, Cd, Cr, Hg concentrations, The results showed that the terrestrial input characteristics of Cu, Pb and Cr in sea water was evident. Zn concentration in the outlet water was high. The difference of each heavy metal concentration in two sediments was low. The enriching ability of seaweed to Zn was relatively high. Generally speaking, the concentration level of heavy metals in the Great Wall Bay was low.

EXPERIMENT OF SHORT WAVE COMMUNICATION AND THE INVESTIGATION OF THE PROPAGATION BEARINGS BETWEEN THE GREAT WALL STATION AND XINXIANG

The distance from the Great Wall Station (62.2°S, 58.9°W) to Xinxiang (35.3°N, 113.8°E) is 16981 km. The path passes through the polar cap absorption region and the auroral absorption zone, and it is across the equator.In this paper firstly the effects of short wave communication and usable time blocks and frequency ranges between the Antarctic Great Wall Station and Xinxiang from December 1985 to March 1986 are introduced. The comparison between the usable frequency ranges with the estimated MUF is made. The upper limit of frequency ranges of communication along the short great circle path basically agrees with the MUF but there is difference between them along the long great circle path.Secondly, the result of the propagation bearings experiment in January to February 1986 is introduced in more detail, The propagation along the great circle path from the Great Wall Station to Xinxiang is the main propagation mode. But the propagation along non great circle paths occurs at times between Great Wall Station and Xinxiang. The non great circle path propagation varies with time because the ionospheric absorption and other conditions which support the non great circle path propagation are the function of the time. So the courses of the non great circle path propagation may be different in the different time. The mechanism of the constructing non great circle path propagation has been analysed. We preliminarily think the main cause of propagation along non great circle path is the ground scatter. The stronger radialization of the side lobes of the antenna and the less absorption of the ionosphere contribute to forming non great circle path propagation.

Recent Vegetation Cover Dynamics and Climatic Parameters Evolution Study in the Great Green Wall of Senegal

The drought recorded in 1970s and 1980s, particularly in the Sahara and Sahel region has greatly affected the population as well as the economies and the eco-systems of this area. In 2007, the African Union launched a Pan-African program, the Great Green Wall for the Sahara, the Sahel Initiative (GGWSSI) to reverse land degradation and desertification by planting a wall of trees stretching from Dakar to Djibouti. The objective is to improve food security, and support local people to adapt to climate change. This paper aims to evaluate the impacts of the reforestation program in Senegal, fifteen years after it was launched. This study uses a time series of satellite-derived vegetation cover and climatic parameters data to analyze the sustainability of these interventions. Change detection approaches were applied to identify and characterize the drives of the eventual changes. A comparative analysis of reforestation on climatic parameters was explored through the temporal analysis of the vegetation index over the periods 2000-2008 and 2009-2020. An increase in vegetation activity was noted through the NDVI at the interannual (+2% to +8%) and seasonal (+1.5% to 7% for the wet season and 1% to 4% for the dry season) scale and a positive and significant evolution is noted on the trace of the GGW. Also, the period 2009-2020 recorded an increase in rainfall of 2% to 8% of the average value 2000-2020 and 4% to 8% of the rainy season. Soil moisture is the climatic parameter that has increased the most, with an increase of 25% to 54% of the 2000-2020 average, i.e. between 20 mm and 70 mm more. This study shows a significant improvement in the relationship between NDVI and climate parameters after the different reforestation actions of the GGW.

THE SIGNIFICANCE OF THE GREAT WALL AS A GEOGRAPHIC BOUNDARY

The Great Wall is not only the symbol of the ancient Chinese culture but also an actual and significant geographic boundary. The arrangements of the wall in past dynasties are based on physiographic conditions, and are just consistent with the demarcation line between semi-humid and arid climates in the country. Therefore,the Great Wall becomes an indicator of the demarcation line between the two areas.The extension and retreat of the wall generally reflect the expansion and shrinkage of farming and animal husbandry areas. From the viewpoint of political geography, the Great Wall can be regarded as the balance belt of 'forces' where the political powers of different nationalities histoncally stood facing each other and had repeated trials of strength. On one hand, the man-made wall of 10,000 li had the function of separating two political units, to some extent, the extension and retreat of the wall reflect the changes of relative strength of the two sides. On the other hand,the conflicts of the advanced and backward forces objectively promoted the economic and cultural exchanges as well as the national assimilation. Today, the Great Wall has lost its function of military works for territorial expansion and defense, but it is still the significant indicator as a geographic boundary and a sensitive area for many geographic elements.

A Case study of a snowstorm at the Great Wall Station,Antarctica

A case of a snowstorm at the Great Wall Station was studied using data of NCEP（National Centers for Environmental Prediction） analysis,in situ observations and surface weather charts.The storm occurred on August 29th, 2006,and brought high winds and poor horizontal visibility to the region.It was found that the storm occurred under the synoptic situation of a high in the south and a low in the north.A low-level easterly jet from the Antarctic continent significantly decreased the air temperature and humidity.Warm air advection at high level brought sufficient vapor from lower latitudes for the snowstorm to develop. The dynamic factors relating to strong snowfall and even the development of a snowstorm were deep cyclonic vorticity at middle and low levels,the configuration of divergence at high level and convergence at low level,and strong vertical uplift.There was an inversion layer in the low-level atmosphere during the later phase of the storm.This vertical structure of cold air at low levels and warm air at high levels may have been important to the longevity of the snowstorm.

Suitability and Construction of Self-Insulation Walls in the Hot Summer and Cold Winter Zone of Southern Shaanxi

In this paper, the suitability and construction technology of self-insulation walls were studied under the specific climatic conditions and regional resources of Hanzhong and Ankang in the hot summer and cold winter zone of Southern Shaanxi. Through the calculation of heat transfer coefficient and thermal inertia index, combined with the specifications of the shale hollow brick and aerated concrete block of Hanzhong and Ankang in southern Shaanxi, the thermal performance and suitable thickness of the external wall using self-insulation materials that meet the Design Standard for Energy Efficiency of Residential Buildings(DBJ61-65-2011) in Shaanxi Province were obtained. The results showed that the self-insulation wall had technical suitability in the hot summer and cold winter zone. The research results provide not only a theoretical basis for the external wall insulation design of urban residential buildings in the hot summer and cold winter zone of southern Shaanxi, but also a reference for designers to carry out energy-saving design of external walls of residential buildings in other similar climate zones.

The climate background and synoptic situation of fog at Great Wall Station,Antarctica

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 arc 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.

The Theoretically Studies and Field Testing of Self-Insulation Exterior Wall in the Hot Summer and Cold Winter Zone

The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation of the exterior?wall is a more feasible design to satisfy the energy efficiency of buildings in the?zone. However, the systematic research is urgently needed for the self-insulation of the exterior wall in the hot summer and cold winter zone of China. The paper tested the thermal performance of the common non-clay materials such as shale sintered hollow brick, sand autoclaved aerated concrete block, etc. by means of indoor experiments. The energy efficiency effect of the common materials was verified using dynamic calculation soft PKPM and several constitutions of exterior wall with different main bricks and insulation materials on the heat bridge were simulated, too. Besides, the tests of the thermal performance of exterior wall in real constructions were carried out to testify the practical effect of the recommended constitutions of exterior wall with different main bricks and insulation materials on the heat bridge. The conclusions are: the physical and thermal properties of the six non-clay wall material are better than the clay porous brick;the thermal performance of the non-clay brick can be improved obviously through the rational arrangement of the holes;shale sintered hollow brick after increasing the holes and rationalizing the hole arrangement and sand autoclaved aerated concrete block are recommended for buildings in the hot summer and cold winter area of China. The dynamic calculation results show that the thermal performances?of the non-clay materials are all satisfied with the energy efficiency;The heat transfer coefficient of the exterior wall with composition?③,?in which?the main wall was sand autoclaved aerated concrete block and the material on the heat bridge was sand autoclaved aerated concrete plate, is the smallest among the three recommended compositions.

A STUDY ON THE QUANTITY OF SHALLOW SEA BENTHOS IN GREAT WALL BAY, ANTARCTICA

Based on the investigation material acquired during the three cruises of the 4 Chinese Antarctic Research Expedition at 19 quantitative dredging stations and 4 trawling stations from the period December 1987 to March 1988, this paper studies the quantity of the benthos in Great Wall Bay,the distributive characteristics and variations, and points out that the stock number of the benthos in the bay is extremely large and that there are two large ranged high mass area and 2 - 3 low small-ranged mass area. The instability of the sediments is the cause for the low.mass areas. The warm season is the vigorous reproductive period of the various kinds of the benthos and the monthly variation of the quantity is remarkable.

ESTABLISHMENT OF SURVEYING SYSTEM OF THE GREAT WALL STATION

It is the main task of the antarctic surveying expedition to establish the surveying system. In three times of the antarctic surveying research expeditions, a complete and accurate surveying system has been established in the Chinese Great Wall Station area. The surveying system includes geodetic coordinate system, elevation system and gravity reference system. In this paper, the surveying methods and the mathematical models for establishing these systems are discussed, and the accuracy of results is analysed.

Delineation of spring capture zones in southern Great Basin,USA based on modeling results and geochemical data

The protection zones or capture zones of springs in desert environments can be hard to identify,but they are critical to spring protection.Most springs fed by regional aquifers are susceptible to contamination and groundwater development.The U.S.Environmental Protection Agency has established hydrogeologic mapping methods to delineate protection zones for springs.However,it is often difficult to determine a regional aquifer system's flow pattern with this technique alone,and the use of these methods is not conducive to efficient groundwater management.Particle tracking analysis using a well-conceptualized and calibrated numerical model for the three-dimensional groundwater flow domain feeding a given group of springs can help facilitate the identification of spring capture zone boundaries.Building upon this basis,a multifaceted approach was developed to define clear boundaries of the capture zones for the springs in the Furnace Creek,Ash Meadows,and the Muddy River areas in the southern Great Basin,USA.Capture zones were first delineated from inverse particle tracking and Hydrologic Unit 12 watersheds.Afterwards,they were adjusted based on water budgets,geology,and hydrologically significant faults.Finally,a geochemical analysis of the groundwater chemistry and isotopic data was conducted to verify the extent of each spring capture zone.This multifaceted approach adds confidence to the new delineations.

Species composition and quantitative variation of zooplankton in the Great Wall Bay and its adjacent waters，Antarctica

A preliminary identification has been made of 35 species of the zooplankton in the Great Wall Bay and its adjacent waters,Antarctica. The dominant species in the investigated area are Calanus propinquus, Calanoides acutus, Metrdia gerlachei and the larvae of antarctic krill.The results indicated that the zooplankton in the investigated waters were simple in species number, which conforms to the general pattern of the distribution of the zooplankton in antarctic waters.The total biomass and number of individuals of the zooplankton in the investigated waters showed obvious seasonal variation. In summer there were Calaninioides acutus and the larvae of antarctic krill; in winter there were Metrdia gerlacher, Calanus propinquus, Oithon similis, O. frigda and the larvae of antarctic krill. The quantity of Copepoda occupied a considerable proportion in each month. The water temperature is an important factor in controling the biomass of zooplankton.

Surface ozone variations at the Great Wall Station,Antarctica during austral summer

Surface ozone(O3)is a secondary pollutant harmful to human health and a greenhouse gas which is one of the prime climate forcers.Due to the clean atmospheric environment of the Antarctic region and given the complexity of O3 chemistry,the observation of surface O3 variability in this region is necessary in the quest to better understand the potential sources and sink of polar surface O3.In this paper,we highlighted our observations on O3 variability at the Great Wall Station(GWS)during austral summer in December 2018 and January 2019.The continuous surface O3 measurement at the GWS,Antarctica was carried out using the Ecotech Ozone analyzer.To understand the roles of the meteorological conditions on the temporal variations of O3,meteorological data was obtained from the conventional auto-observational station at the GWS.The Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model was employed to investigate the air mass transport over the region.The observed austral summer surface O3 concentrations at the GWS exhibited variability and were significantly lower than those previously observed at other permanent coastal stations in Antarctica.The surface ozone variability at the GWS was strongly influenced by the synoptic change of air mass origin although the roles of photochemistry production and destruction were still uncertain.Marine characteristics and stable surface O3 characterized the air masses that reached the GWS.The unique characteristic of surface O3 at the coastal site of GWS was emphasized by its synoptic air mass characteristics,which displayed a significant influence on surface O3 variability.Air mass that traveled over the ocean with relatively shorter distance was linked to the lower O3 level,whereby the marine transport of reactive bromine(Br)species was thought to play a significant role in the tropospheric chemistry that leads to O3 destruction.Meanwhile,the diurnal variation indicated that the O3 background concentration levels were not strongly associated with the local atmospheric conditions.

The preliminary study of the phytoplankton ecology in the Great Wall Bay，Antarctica

This paper presents the identification and quantitative analysis of the phytoplankton samples collected in the Great Wall Bay, Antarctica from March 1988 to February 1989. The results indicate that the specific composition of phytoplankton clearly shows their ecological characteristics. That is the community mainly composed of cold-water species and neritic-eurythermal species. The dominant species altered with seasonal variation, their number showed the high-peak in the austral summer and the abundance of phytoplankton in each month mainly depended upon the dominant species. The distribution of phytoplankton is influenced by many environmental factors. Among them the hours of sunshine are the main factor.

ON CHEMICAL WEATHERING OF WEATHERING CRUST AT THE GREAT WALL STATION REGION, ANTARCTICA

The chief aim of this study is to investigate the chemical weathering process of the weathering crust in Great Wall Station region of China (in Fildes Peninsula), Antarctica by the method of sedimentology.CW,SW,GW,TW,WE weathering crusts developed on volcanic clastic rock, gray aptitic basalt with tuff or basaltic bedrock. On change of minerals, geochemical behaviors of elements, migration and enrichment regularities of elements, Correlation between element geochemical behaviors, change of weathering potential of rocks in chemical weathering process are studied by us.We can see that the sequence fo weathering strengths of the abovementioned sections, from high to low, should reflected in TW, GW, CW and SWT and basical correspond with that calculated from the enrichment and differentiation indexes.

A preliminary analysis of the pigments from ice algae in theadjacentwatersofGreatWallStation，Antarctica

This paper reports the results of separation and identification of the pigments from ice algae in the adjacent waters (62°12′30″S～62°14′30″S, 58°53′W～ 58°57′W) of Great Wall Station, Antarctica during the icing Pened (from June 1988～ December 1988) and the discussion is also made on the composition and seasonal variations of the pigments of ice algae in that area as well as their roles in marine ecosystems. The results indicate that 15 kinds of pigments have been separated from ice algae, of which 13 kinds can be identified. They are respeCtively: carotene, pheophytin-a, chlorophyll-a, -b, -c, xanthophyll, fucoxanthin, chlorophyllide-a, violaxanthin, pheophorbide-a, chlorophyllin-a, derivative of chlorophyll-c (diadinoxanthin), but two kinds of pigments can not be identified. There are distinct seasonal variations in the pigments of ice algae at that sea area.

The amount of hydrocarbon bacteria in the Great Wall Bay and its adjacent area

During the summer of Antarctic in 1993/1994, the species and amount of hydrocarbon bacteria of the Great Wall Bay and its adjacent sea area have been studied. Flavobacterium,Pseudomonas,Kurthia and Actinetobacter have been identified .The number of them varied from 3 cell/L to 1100 cell/L.The number in the inner bay is larger than that out of it.The dispersing is a very important way of the changing of hydrocarbon bacteria.

The separation and identification of phytoplankton pigments from the adjacent waters of Great Wall Station，Antarctica

This paper presents separation and identification of the pigments of the phytoplankton samples collected from the adjacent waters (62°12. 5'S, 58°53' W～62°14. 5' S, 58°57' W) of Great Wall Station, Antarctica during March 1988～February 1989 by using thin-layer chromatographic techniques. Of the 15 kinds of phytoplankton pigments separated, 13 were identified according to the R. values of the various marine algal pigments. The features of seasonal variations of phytoplankton pigments in the studied area are also discussed.