25 February 2003, Volume 25 Issue 1
    

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  • Climate Regime of the Coastal Antarctic Ice Sheet over the Past 50 Years Indicated by the Ice-core and Meteorological Records
    XIAO Cun-de, QIN Da-he, REN Jia-wen, LI Zhong-qin, ZHANG Ming-jun, SUN Wei-zhen, WANG Xiao-xiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 1-10. https://doi.org/10.7522/j.issn.1000-0240.2003.0001
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    Ten firn cores, in which five locates at the eastern side and another five at the western side of Lambert Glacier basin (LGB), were contrasted for their records of snow accumulation and isotopic temperature for the recent 50 years. It is demonstrated that snow accumulation at the five sites over the eastern side (i.e., GC30, GD03, GD15, DT001 and DT085, which locate at Wilks Land and Princess Elizabeth Land) of LGB increases, whereas those at the western side (i.e., Core E, DML05, W200, LGB16 and MGA, which locate at Dronning Maud Land, Mizuho Plateau and Kamp Land) decreases. For the past decades, the increasing rate at the eastern side was between 0.34～2.36 kg·m-2·a-1, and the decreasing rate at the western side between -0.01～-2.36 kg·m-2·a-1. Temperatures at the eastern LGB were also increasing, with the rate around 0.02 a-1. But at the western LGB it was much more complex. Instrumental temperature records at coastal stations confirm this complexity;Although statistic study and modeling display that both surface temperature and accumulation rate display increasing trends in Antarctic ice sheet for the period 1950-2000, the regional temperature distribution is much different, even converse over in some geographical units. It is believed that the ice-core records at Wilks Land and Princess Elizabeth Land reflect the real variations of sea surface temperature and moisture change in the southern India Ocean. But for the Kamp Land and Dronning Maud Land, varied circulation pattern complexes the climate;The International Trans-Antarctic Scientific Expedition has its initial aim to reveal an overall spatial pattern of climatic change on Antarctic ice sheet for the past 200 years. This study will re-confirms the importance of continental to regional scaled circulation to annual-decadal scaled climatic change in Antarctica.
  • Climatic Differences in China during the Holocene Indicated by the Various Climatic Proxy Data from Different Parts of China
    HE Yuan-qing, YAO Tan-dong, SHEN Yong-ping, ZHANG Zhong-lin, CHEN Tuo, ZHANG Dian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 11-18. https://doi.org/10.7522/j.issn.1000-0240.2003.0002
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    For a better understanding of climatic variations in China during the Holocene, climatic records from two ice cores in Tibetan Plateau are compared each other and with other proxy data, such as loess, lake sediments, pollen, changes of sea and lake levels in different parts of China. After an abrupt cooling event of Younger Dryas between 12.2 ka and 10.5 ka BP, δ18O values in the Guliya ice core (35°17’ N, 81°29’ E, 6710 m a.s.l) in the early Holocene between 10.5 ka BP and 7.2 ka BP were high, indicating the continues warmer and wetter climatic conditions lasted for 3 000 a. Whereas in the mid-Holocene between 7.2 ka BP and 5.0 ka BP, another abrupt cooling occurred, reflected by a sudden decrease of isotopic composition from 7.2 ka BP. Then δ18O values gradually increased from 5.0 ka BP to present, except for a relative lower isotopic stage between 3.5 ka and 2.5 ka. Differentially, in Dunde ice core (38°06’N, 96°24’E, 5 325 m a.s.l.), frequent variations of higher and lower δ18O values have observed during the Holocene. The megathermal maximum started from 8.7 ka BP, characterized by a sharp increase of δ+18O values, continued until 3.0 ka BP, and followed by a gradually decreased trend of isotopic composition. However, many short-term colder stages appeared in the more than 5000 a long Megathermal period of the Holocene, especially there was an unstable-temperature stage between 6.0 ka BP and 5.0 ka BP. Climatic changes indicated by isotopic records in the two cores are inconsistent, probably as a result of differences of altitudes and atmospheric circulations when ice was deposited. It is inferred that air masses with more precipitation at Guliya came from the continental sources due to its interior position and higher altitude in Tibetan Plateau but precipitation at Dunde was disturbed by maritime air masses of the summer monsoon because its site is located in the edge of the plateau and at a lower elevation. There are different climatic indications of δ18O values between continental and maritime-origin vapor sources, which have been confirmed by some studies dealing with the isotopic distribution of precipitation in Tibetan plateau. Paleoclimatic data from other mediums in different parts of China are used to compare with the climatic records from above two ice cores. In the most loess profiles studied, higher magnetic rates were measured between 10.0 ka BP and 5.0 ka BP, when a warmer and wetter period appeared, and then became progressive cooling in late 5000 a, with overall decreased magnet rates, although there were some higher-rate stages during the period, corresponding to the higher sea levels in eastern China. However, higher levels of lakes in western China occurred longer, from 10.0 ka BP to 4.0～3.0 ka BP. Climatic warming in the Holocene indicated by pollen charts from lacustrine deposits seems starting earlier in western China than that in eastern China. Proxy data from most mediums displays obvious climatic fluctuations in the most recent 500 a, named as the Little Ice Age.= In summary, climatic records in the Holocene recovered from the Guliya and Dunde ice cores are inconsistent because of their different locations and elevations, which may be controlled by different atmospheric situations when ice formed. The climatic changes indicated by the Guliya ice core in the interior of the Tibetan Plateau correspond well to the climatic records from other polar and tropical ice core, such as those from Greenland and Huascaran, as well as those from deep-sea sediments, which probably reflects a global climatic trend during the Holocene. However, the climatic information in the Dunde ice core is more complex and associated with the proxy climatic data from other mediums, such as loess, lacustrine sediments, changes of sea and lake levels in eastern and middle parts of China, which was more influenced by the prevailing monsoon during the Megathermal in the Holocene. Referring to the most proxy data, it seems that the climate varied earlier and more sensitive in high
  • The Environment Disaster Events and the Evolution of Man-land Relation in the West Liaoning During 5000 a BP
    LI Yong-hua, YIN Huai-ning, ZHANG Xiao-yong, CHEN Zhan-jiao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 19-26. https://doi.org/10.7522/j.issn.1000-0240.2003.0003
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    In this paper West Liaoning is referring to the northwest part of Liaoning Province and one part of the eastern Inner Mongolia Autonomous Region. It includes some counties of Liaoning Province, such as Fuxin, Zhangwu, Kangping, etc., and the east parts of Ju Ud League and Jirem League of Inner Mongolia. West Liaoning is located in the agriculture-pasture interlacing zones in northern China and located in the transitional zones of ecological system, sensitive to globe change. Since the middle-late Holocene, cultural development in this area had suffered stagnation, and even retrogression; in the meantime, its environment was deteriorated owing to climate fluctuation and human activities;Muchang peat section, the high-time-resolution geological records at present, reflects the environmental change and human activities of historical periods in West Liaoning. According to the records, the environmental changes during the past 5000 a can be divided into 4 calamitous phases. They are 5000～4400 a BP cold event, 2700 a BP cold event, the large-scale agricultural development in Liao Dynasty-Jin Dynasty and the war turmoil in Ming Dynasty-Qing Dynasty, respectively. In addition, the geological records and historical documents also confirmed the environmental changes and human activities in the neighboring areas;It is the environmental condition that becomes the essential factor of the early cultural development in West Liaoning, especially climatic condition. Agriculture was prosperous in warm period, while simple livestock farming economy with low level was in cold period. Cold event in 5000～4400 a BP and the cold climate in ironware age directly caused the production-economy formation changing and culture falling behind from the new Stone Age to the Bronze Age. The violent fluctuating process of environmental factor foreclosed the normal evolution and development of early culture and production-economy formation in West Liaoning;At present, the aggravated environment in West Liaoning is caused by the following factors: a large scale of agricultural development since Liao Dynasty-Jin Dynasty, a continual cold climate since Xizhou Dynasty, the war turmoil since Ming Dynasty-Qing Dynasty, and the Little Ice Age, etc.
  • The Response of the Climate Records in the Guliya Ice Core to ENSO Events
    YANG Mei-xue, YAO Tan-dong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 27-33. https://doi.org/10.7522/j.issn.1000-0240.2003.0004
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    El Nino-Southern Oscillation (ENSO) is a global event caused by the sea-atmosphere interaction in large scale. The period of ENSO is 2～10 a. In the lower and middle latitudes of the world, ENSO event is one of the very important factors for climate variation. Many scientists studied the impact of ENSO events on the climate in China. The studies of ENSO and precipitation variations in semi-arid regions in northern China showed that El Nino events corresponded with the deficit of precipitation in northern China and the Southern Oscillation Index (SOI) significantly correlated with precipitation variations. In this paper, based on the El Nino Chronology and other El Nino-Southern Oscillation index, using precipitation and temperature data recorded in the Guliya ice core, the response of the climate records in Guliya ice core to the ENSO events was examined;The Guliya ice cap (35°17’ N,81°29’ E), with the elevation of 6200～6700 m, located in the West Kunlun Mountains. It was demonstrated that the glacier net accumulation in the Guliya ice cap is a good proxy index for precipitation. Thus, the net accumulation recorded in the Guliya ice core can be used as precipitation. Meanwhile, it was also showed that the δ18O recorded in the Guliya ice core is a good proxy index for temperature;Due to the ENSO event caused by the sea-atmosphere interaction in large scale. It occurs every 3～5 a and its spectrum width is 2～10 a. Firstly, the net accumulation and δ18O from 1690 to 1991 recorded in the Guliya ice core was expressed by 10-year Gaussian moving average. The differences of the raw data (high-passed filtered data) and the moving average data were used as the anomaly in the following analysis. If only the anomalies from the raw data were used in analysis, the response signals of the climate records to El Nino events will be affected by the low frequency variation. So, it is necessary to use the high-passed filtered data. The high-passed filtered data can ensure that any significant relationship is not caused simply by the low-frequency variation of the series itself. The high-passed filtered data was used in the following analysis;From 1690 to 1991, there were the El Nino years with less precipitation and lower temperature recorded in the Guliya ice core. However, it was exceptional from 1920 to 1930. Especially, in the El Nino years since the 1940s, δ18O was basically positive anomaly. This probably related with the global warming in the last decades. The Mann-Whitiney U-test results demonstrated that precipitation significantly decreased in El Nino years from 1690 to 1991(P<0.05). This is especially true during 1840 to 1991(P<0.005). But from 1690 to 1984, the correlation has not reached to the significant level. This is basically coincident with the results presented here. Although the most of the El Nino years corresponded with the lower δ18O, δ18O have not reached to the significant level;ENSO event and its intensity can be evaluated by SOI. In order to confirm the relationship between ENSO events and climate anomalies recorded in the Guliya ice core, the SOI from 1882 to 1991 and the precipitation recorded in the Guliya ice core were compared. In most cases, less precipitation recorded in the Guliya ice core is associated with lower SOI from autumn to spring and vice versa;Due to the reliability of the instrumental records of ENSO events during World War Ⅱ is not so good and the observation techniques on the sea were modified about 1940, a new ENSO index MEI (Multivariate ENSO Index) was used. Comparative studies showed that the response of precipitation recorded in the Guliya ice core to El Nino events is associated with the onset time and the intensity of the El Nino events.
  • The Quaternary Glaciations and Glacier Properties in the Tanggula Range
    JIAO Ke-qin, SHEN Yong-ping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 34-42. https://doi.org/10.7522/j.issn.1000-0240.2003.0005
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    The occurrence and development of the Quaternary glaciers in the Tanggula Range was closely related to the amplitude and time of mountain uplift and climatic conditions. The evolution process of the glaciers in the range did not completely accord with that in other regions of the Tibetan Plateau, and the number of glaciations was not completely the same. Since the mid-Pleistocene epoch, three Pleistocene glaciations (i.e., the Kunlun Ice Age, the Penultimate Ice Age and Last Ice Age) and two two Holocene glaciations (i.e., the Neoglaciation and the Little Ice Age) have occurred in the Tanggula Range. The Kunlun Ice Age occurred in the early mid-Pleistocene epoch (0.80～0.60 Ma BP), which was not only the earliest ice age, but also the largest glaciation in this range. The glaciers developed over the main ridge connected together, forming a huge ice cap with piedmont glaciers, of which the size was 16～18 times larger than that at present. The Penultimate Ice Age occurred in the late mid-Pleistocene (0.30～0.135 Ma BP), when the size of glaciers, still large ice cap with piedmont glaciers, was smaller than that in the preceding ice age but was 13～15 times larger than that at present. The Last Ice Age occurred in the late period of the late Pleistocene, which can be divided into the earlier ice age (75.0～58.0 ka BP) and the latter ice age (32.0～15.0 ka BP, with the largest scale of glaciers during 23.0～16.0 ka BP). Up to now, however, the glacial vestiges of the earlier ice age have not been found in field investigation and in the research of the Quaternary glaciers yet. Therefore, this paper discusses the latter ice age of the Last Ice Age (i.e., Last Glacial Maximum) only. During the latter ice age of the Last Ice Age, the scale of glaciers, mainly in the form of ice cap and valley glaciers, was 10 times larger than that at present. The Neoglaciation occurred after the high-temperature period of the Holocene epoch ( 14C dating (5805±173) a BP), when the 14C age was (3540±160) a BP, and the scale of glaciers was slightly larger than that at present. The Little Ice Age occurred during the 1500 s～1800 s, and the scale of glaciers was close to that at present;The scale of glaciers in the Tanggula Range has become smaller and smaller since the Kunlun Ice Age, because of the drying process in the hinterland of the Tibetan Plateau due to the uplift of the plateau. The evolution course of glacial climate type was monsoon maritime →transitional monsoon maritime-continental→monsoon continental→continental.
  • Analysis on the Thawing of Permafrost underlying Qinghai-Tibetan Highway
    SHENG Yu, LIU Yong-zhi, ZHANG Jian-ming, WU Jin-min, ZHANG Jin-zhao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 43-48. https://doi.org/10.7522/j.issn.1000-0240.2003.0006
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    Construction of the Qinghai-Tibetan Highway will change the heat exchange between atmosphere and ground surface, destruct the original heat balance, resulting in a heat accumulation in highway embankment and underlying permafrost and permafrost thawing. This is the greatest problem in the construction in permafrost regions. General principle for the construction of the highway is to try to keep the underlying permafrost from thawing. In order to realize the purpose, it is very important to have a good understanding of the thawing state of permafrost underlying the highway embankment. Based on two series of observations of ground temperature profile, both in high temperature and low temperature regions, the thawing state of permafrost underlying the highway is stated, and the heat penetrating into permafrost is analyzed in this paper. It is revealed that the ground temperature near the highway surface is obviously higher than that of natural ground surface, and that the thawing period of the highway embankment is longer than that of natural ground. Permanent thawed layer has formed in high temperature regions. The heat budget within the permafrost underlying the highway shows a continuous heat-taking state in high temperature regions. The heat income within the permafrost in low temperature regions is greater than the heat release from the permafrost during an annual period. It is the high temperature (near 0℃) and continuous heat accumulation in high temperature regions that induces the thawing of the performed underlying the highway. The heat accumulation within the permafrost underlying the highway in low temperature regions is temporarily performing as permafrost temperature rising, and with increasing ground temperature, considerable thawing of permafrost is also possible.
  • Interannual Variation of the Beginning Date and the Ending Date of Soil Freezing in the Tibetan Plateau
    GAO Rong, WEI Zhi-gang, DONG Wen-jie
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 49-54. https://doi.org/10.7522/j.issn.1000-0240.2003.0007
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    By using the upper limit and lower limit of frozen soil in 58 meteorological stations from 1981 to 1999 in Qinghai Province and Tibet Region, the special distributing and inter-annual variation of the beginning date and the ending date of the soil freezing is analyzed;When soil begins to freeze in fall, the early, the late and the mean beginning dates occur from north to south gradationally. Soil freezes early in the northeastern Qinghai Province and in the source areas of the Yellow River. Soil freezes late in the northern slopes of the Himalayas, the southeastern and the northern Tibet Region. When soil concludes to freeze in the spring, the early, the late and the mean ending date is rather consistent, early in the south and north of the plateau and late in the Middle Plateau. Soil thaws early in the northern slopes of the Himalayas, the southeastern Tibet Region, the Qaidam Basin and the northeastern Qinghai Province. Soil thaws late in the northern Tibetan Region and the source areas of the Yellow River;The difference between the last and the earliest beginning dates of soil freezing are 20 d to 90 d in different stations. The maximum difference, more than 50 d, appears in the source areas of the Yellow River, the southeastern and the northern Tibetan Region. The difference between the last and the earliest ending dates of soil freezing are 30 d to 90 d in different stations. The maximum difference concentrates in Qaidam Basin;The series of the beginning date of soil freezing varies in a period of 3～4 a, while that of ending date of soil freezing varies in a period of about 7 a. Thus the frozen days varies in a period of 2～6 a. The cumulative depth and the maximum depth of frozen soil varies in a period of 3～8 a, but the variation is slight, which cannot pass the significance test of 5%;The beginning date of soil freezing has a trend to occur latter and the ending date of soil freezing has a trend to occur earlier, showing permafrost is degenerating in the plateau. In the 1980s, the soil frozen early and thawed late, resulting in a longer frozen duration. But in the 1990s, the soil frozen late and thawed early, resulting in a shorter frozen duration;In 1981 and 1982 soil frozen early and thawed late; 1983 and 1990 soil frozen late and thawed late; 1993 and 1999 soil frozen late and thawed early.
  • Dynamic Observation and Analysis of Moisture and Temperature Field Coupling Process in Freezing Soil
    MAO Xue-song, HU Chang-shun, DOU Ming-jian, HOU Zhong-jie
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 55-59. https://doi.org/10.7522/j.issn.1000-0240.2003.0008
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    Based on an observation on the moisture field and temperature field changing with time in freezing soil, this paper makes a numerical simulation of the test results by citing the heat-moisture coupling model of one dimension vertical freezing soil system established by Doctor Flerchinger and the correlative relation equation and boundary condition. The precision and usability of the model are verified.
  • The Recent Change of Water Level in the Bosten Lake and Analysis of Its Causes
    WANG Run, Ernst Giese, GAO Qian-zhao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 60-64. https://doi.org/10.7522/j.issn.1000-0240.2003.0009
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    Since 1987 the water level of Bosten Lake in Uygur Autonomous Region of Xinjiang has risen continuously, and the lake area reached the greatest since the 1950 s. It can be supposed that this change is related directly to the increase of runoff in the Kaidu River, which supplies about 85% of water in the whole catchments. Naturally, the runoff of the Kaidou River is influenced much more by the fluctuation of climate, since the river originates from glaciers and snow cover in the Tianshan Mountains. Much research work about the global change showed the evident ascending tendency of annual average air temperature in the last 20 years in Central Asia. Additionally, the local climate data also manifested a warming up. In this paper the relationship between the warming up and the increasing of runoff is analysed with the selected air temperature data in the east ranges of the Tianshan Mountains. Although the result shows that the increasing of runoff is correlative with climate change, it is not clear either glacier ablation or precipitation plays more important role in the level change in the Bosten Lake. Because of lack of precipitation data in the high altitudes of the Tianshan Mountains, the question remained is how to determine the direct cause for the change of water level. Some research methods for this question are checked and discussed in this paper. The influence of climate change on water resources in a catchment is critically examined with an example in the Glacier National Park.
  • Study on the Fractionation Mechanism of Stable Isotope in Evaporating Water Body
    ZHANG Xin-ping, YAO Tan-dong, TIAN Li-de
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 65-71. https://doi.org/10.7522/j.issn.1000-0240.2003.0010
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    The interaction between evaporating water body and atmosphere and the influence of different factors on evaporation are analyzed by probing into the fractionation mechanism of stable isotope as water body is vaporized under kinetic non-equilibrium and by comparison of the kinetic fractionation model with the Rayleigh equilibrium model;A simple description of stable isotopic fractionation in the process of evaporation is Rayleigh Model. Under Rayleigh equilibrium, the following results are obtained: a) stable isotopic ratio in residual water increases with the decrease of the residual water proportion f exponentially; b) the fractionation rate of stable isotopes is inversely proportional to temperature; c) the simulated Rayleigh distillation line changes with temperature. The higher the temperature, the less the slope and the constant of the distillation line. The simulated distillation line is near global Meteoric Water Line as the temperature is about 20℃;Besides temperature, the relative humidity h and the stable isotopic ratio in atmosphere δa also influence the variation of stable isotopic ratio in residual water in the process of kinetic evaporation. The simulations show that, the less the h, the quicker the variation rate, with f, of stable isotopic ratio in residual water. For great h, the ratio δ in residual water will not change with f after the evaporation running for a long time, namely isotopic composition in residual water reaches a stable state. The rate of isotope reaching stable state is dependent on the relative humidity in atmosphere mainly;Compared with the simulated results by Rayleigh Model, the enrichment degree of stable isotopes in residual water is distinctly higher, and the fractionation rate of stable isotopes is directly proportional to temperature under kinetic evaporation, as taking the relative humidity equals to 50%. The higher the temperature, the quicker the fractionation rate, which is exactly reverse to the result simulated by Rayleigh Model. Using the kinetic model, the calculated variation rates, with f, of the δ18O in residual water are -28.27 for T=30℃, -30.40 for T=20℃ and -32.70 for T=10℃, respectively, as taking h=40%. These values are comparative with the evaporation experiments carried out in Nagqu of the middle Tibetan Plateau;Under the non-equilibrium condition, the gradient and constant values of the simulated distillation line are directly proportional to temperature and relative humidity. An observation in the Qinghai Lake demonstrates that the initial stable isotopic ratios δD=-60.6‰ and δ18O=-10.86‰ in the water of the Qinghai Lake, the annual mean temperature T=0.65℃ and the relative humidity h=55%. Inputting above data into the kinetic fractionation model and taking β=1.006, a good agreements between the simulated distillation line (δD=5.56 δ18O-1.51) and the observed line(δD=5.55δ18O-0.30) was obtained.
  • Spatial Differences of Hydro-Chemical and Its Control Factors of the Headwater Runoff in the Ürümuqi River, Tianshan Mountains
    LI Cui-lin, HOU Shu-gui, QIN Da-he
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 72-76. https://doi.org/10.7522/j.issn.1000-0240.2003.0011
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    The hydro-chemical characteristics of stream flow within the headwater drainage of the Ürümuqi River, Tianshan Mountains, is affected by various factors, such as precipitation, glaciation, snow melting, permafrost active layer, moraine components and talus-soil-water interaction in warm season. The wide meltwater-soil interaction and chemical denudation of mineral solutes dramatically contribute to the stream water, resulting in higher solute concentration in stream water than that in precipitation. Pyrite oxidation, calcite dissolution and K-feldspar hydrolyze are the main reactions, causing high Ca2+, K+, SO42- concentrations and weak alkaline pH value in stream water. Ca2+, Mg2+, SO42- and K+ concentrations with their ionic pulse peaks in the Glacier No.1 are much higher than those in the Dry Cirque and the Total Control Gauge Section due to more effective snow melting and glacier grinding on the underlain rocks that boosts mineral dissolution. Stream flow in the Dry Cirque is more influenced by precipitation, except for soil-restored meltwater mixing and soil-water interaction. The Total Control Gauge Section generally shows a mixed effect of the Glacier No.1 and the Dry Cirque.
  • Trend Analysis of the Precipitation and Runoff in the Taohe River Watershed during the Past 50 Years
    ZHANG Ji-shi, KANG Er-si, LAN Yong-chao, CHEN Ren-sheng, YAO Jin-zhong, PU Rui-feng, CHEN Man-xiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 77-82. https://doi.org/10.7522/j.issn.1000-0240.2003.0012
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    Analyzing the past 50 a hydrological and meteorological data in the Taohe River basin, it is clear that precipitation and runoff decreases and temperature slowly rises. In the past 50 precipitation decreased 43～67 mm, runoff decreased 78.5～168 m3·s-1·a-1, and temperature increased 1℃. This trend was significant in the 1980s and the 1990s. Precipitation decreased 10.2% from the 1980s to the 1990s, runoff decreased 33%～36% from the 1980s to the 1990s, the decreasing range of runoff was 3 times larger than that of precipitation. Since the 1960s temperature in the upper reach has slowly increased. Temperature increased 0.5℃ from the 1970s to the 1980s, and 0.6℃ from the 1980s to the 1990s;Decrease in precipitation and runoff mainly occurs in May～October, and in November～April the decrease range is very small. However, temperature variation trend is opposite to precipitation and runoff.Increase in temperature mainly occurs in November～April, and in May～October, the increase range is very small;In the basin, multi-annual average total surface ground water resources is 47.16×108 m3·a-1. In the 1950s the annual average total surface ground water resources was 46.25×108 m3·a-1, in the 1960s it was 59.05×108 m3·a-1, in the 1970s it was 47.51×108 m3·a-1, in the 1980s it was 49.42×108 m3·a-1, and in the 1990s it was 33.2×108 m3·a-1. Its decreasing amplitude was 32.8% from the 1980s to the 1990s. From 1996 to 2000 the decrease speeds up, resulting in the annual average total surface ground water resources equivalent to 36.6% of the multi-annual average;The decrease of precipitation and runoff and the increase of temperature cause drought and desertification, together with disappearance of many wetlands or lakes in Gannan Grassland. This variation also worsens environment, and will spreads to the design of Taohe River Water Diversion Irrigations Project. Public will doubt the feasibility of the Taohe River Water Diversion Irrigations Project. So it is necessary to enhance the study of the impact of climate change on water resources, and to present scientific measures to the project.
  • Spatial Distribution of Stable Carbon Isotope Compositions of Plant Leaves in the North of the Tibetan Plateau
    CHEN Tuo, YANG Mei-xue, FENG Hu-yuan, XU Shi-jian, QIANG Wei-ya, HE Yuan-qing, AN Li-zhe
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 83-87. https://doi.org/10.7522/j.issn.1000-0240.2003.0013
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    Tibetan Plateau is an important position for studying the global changes due to its ecological vulnerability and climatic sensitivity. The stable carbon isotope compositions in plant leaves can be used to provide information of original carbon in soil organic matter and paleo-ecological evolutions, based on the good relationship between the stable carbon isotope compositions and water use efficiency in plants or plant productivity to some extent. However, the pattern of spatial distribution of stable carbon isotope compositions of plant leaves in the Tibetan Plateau is less studied. The aim of this study is to determine the effects of altitude, latitude and longitude on foliar δ13C values and their mechanisms;A total of 101 samples used in this study were collected from 13 sites in the northern part of the plateau. The analyses show that foliar δ13C, with an average of -26.89‰, ranged from-29.52‰ to -23.85‰. The δ13C increased with increasing altitude and decreasing latitude and longitude. There was a statistically insignificant effect of soil water contents and soil temperature on the foliar δ13C. These results suggest that altitude effect of foliar δ13C was mainly ascribed to temperature and atmospheric pressure (the partial pressure of CO2), while temperature and relative humidity were possibly responsible for the latitude and longitude trends of foliar δ13C.
  • The Relationship Between Foliar Stable Carbon Isotope Composition in Pedicularis L. and Environmental Factors
    FENG Hu-yuan, AN Li-zhe, CHEN Tuo, XU Shi-jian, QIANG Wei-ya, LIU Guang-xiu, WANG Xun-ling
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 88-93. https://doi.org/10.7522/j.issn.1000-0240.2003.0014
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    There are two stable carbon isotopes in nature, 12C and 13C. During the process of photosynthesis, the heavier 13C isotope of atmospheric CO2 is discriminated against the lighter 12C, because of differences in physical and chemical traits, leading to the poorer value of 13C/12C in plant tissues, organs or chemical compositions. Most studies showed that δ13C value in plant tissues reflects the effects of environmental factors on plant physiology and growth. In recent years, stable carbon isotope techniques were wide used in geography, ecology, genetics, agronomy and global change research. Pedicularis L. (Scrophularicaceae) has 500 species or more in the world, and near 400 of them are distributed in China. They favor the place with water, and thereby one can hypothesized that water status has a little impact on foliar δ13C in the genus of Pedicularis L. other than environmental conditions, such as atmospheric CO2 partial pressure, air temperature and effectively cumulative temperatures. To test this hypothesis, 47 species and/or samples were collected in 13 sites from Guyuan County of Ningxia Hui Autonomous Regions, Tianshan Mountains of Uygur Autonomous Region of Xinjiang, Zhouqu County, Luqu County, Maqu County, Diebu County, Yuzhong County, Subei County, Hezuo City, Minxian County, Chengxian County, Zhouni County, Tianzhu County and Xiahe County of Gansu Province. Foliar stable carbon isotope was measured with Mat-252, and correlative analysis was done between δ13C and altitude, longitude, latitude, mean annual temperature, cumulative temperature of greater than 10℃, mean annual precipitation and humidity, respectively. Different δ13C value was founded among species and sampling sites. The sample of P. cheilanthifoilia in Maqu County (3400 m a. s. l.) had the largest value (-22.4‰), and P. anas var. xanthantha from Zhuoni County (2500 m a. s. l.) was the least (-31.5‰), and the mean δ13C values of all samples was -27.1‰. The relationship between δ13C values and mean annual precipitation and humidity was not significant (P>0.05), δ13C values of all sites had significantly relationship with mean annual temperature and cumulative temperature of greater than 10℃(r=0.34 and r=0.40,P<0.05). Foliar δ13C values in Pedicularis sample obviously increased with increasing altitude and latitude, (r=0.37 and r=0.31, P<0.05); in contrast, δ13C had negative relationship with longitude (r=0.29, P<0.05). The result supports the previous hypothesis, and indicates that photosynthetic capacity and temperature may play more important roles to affect the isotope composition of Pedicularis.
  • Research on the Landscape Pattern of Zhangye Oasis in the Middle Reaches of Heihe River
    JIAO Yuan-mei, MA Ming-guo, XIAO Du-ning
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 94-99. https://doi.org/10.7522/j.issn.1000-0240.2003.0015
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    In this paper, Zhangye Oasis, a famous agricultural base located in the alluvion of Heihe River in Northwest China is selected as study area. Landscape maps are compiled based on the landuse maps interpreted from Landsat TM images in 1995. Various landscape metrics are calculated by using the landscape structure analysis software-FRAGSTATS Version 3 at class and landscape levels, including total area of landscape, percentage of landscape types, patch density, edge density, largest patch indices, perimeter-area fractal dimension, interspersion & juxtaposition index, aggregation index, percentage of like adjacencies, patch cohesion index, Shannon’s diversity index, Shannon’s evenness index, patch richness and contagion. The results indicate that: desert, grassland, field and gobi are the major components in the oasis. The landscape patterns of the oasis are heterogeneous mosaics embedded in desert and gobi landscape matrix. Patches number of rural villages is the largest, which indicates the important influence of human beings. They are scattered in the whole landscapes and the cohesion indices is the lowest, because they are unconnected each other. The shape of bare rock and grassland are the most complex, which reflected the human-induced fragmentation of these types. In addition, the better connection of dry field, Gobi and bare rock indicate that the energy and mass can be transferred within the same types easily. At last, the caution of scale dependent of grid and classification was discussed.
  • Study on Construction Technology for Cutting Blasting in High-ice-content Permafrost Region at Kunlun Mountain Pass on Qinghai-Tibet Railway
    WANG Yong-yi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 100-105. https://doi.org/10.7522/j.issn.1000-0240.2003.0016
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    In certain circumstances, construction of cuttings in high-ice-content permafrost region in warm season is un-avoided; hence, risk of construction and difficult extent for technology and organization of construction is increased. This article is aimed at introducing the basic principle, process, technology and measures for blasting of high-ice-content permafrost cutting in warm season, taking a typical construction on Qinghai-Tibet Railway as an example;The basic principle for the construction are as follows: 1) to make construction time table in accordance with the characteristics of temperature differences on plateau during day and night, so as to avoid construction under high temperature; 2) to organize the operation in succession and fast-speed, in order to limit the exposure time of permafrost; 3) to facilitate water drainage on the top of cuttings and construction yard in advance based on the principle of "water drainage system first and main construction second"; 4) to carry out cutting blasting on the basis of "it is better over excavation than under excavation" so as to meet the needs of designed thickness of top-soil replacement; Cutting blasting is to be carried out in two layers, i.e. a layer of protection, 2 m in thickness, shall be kept for lessening the interruption to the permafrost foundation base. 5) to carry out cutting blasting without any damage to ecology environment adjacent to facilities or beyond excavation clearance of the railway;Methods for blasting operation: for main excavation, loosening blasting with multiple rows of differential and deep/shallow holes is to be adopted; For gently slopes with high-ice-content permafrost vertical drilling hole blasting is proposed, with cushioned charging structure at the bottom of blasting holes, in order to raise blasting efficiency, speed up the construction and maintain the permafrost slope in good and stable state, meanwhile, attention shall be paid to blasting parameters and depth of drilling holes. Blasting materiel used are 32 No.2 explosive emulsion for rock blasting, 60RYY-Ⅱ explosive emulsion, plastic primacord non-electric detonator system;Technology of construction: construction technology selected is the fundamental part for cutting blasting with high-ice-content permafrost. Its key technology is featured with a word "fast", so, each operation of construction process shall be planed as a whole and tight scheduled without interruption, so as to catch favorable time for the construction.
  • Constructing Technology Research on Water-proof/Drainage and Heat Insulation Lining in Kunlunshan Tunnel of Qinghai-Tibet Railway, Tibetan Plateau
    ZHOU Jing-zhui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 106-111. https://doi.org/10.7522/j.issn.1000-0240.2003.0017
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    Kunlunshan Tunnel on Qinghai-Tibet Railway, 1686m in length, the world longest permafrost tunnel on plateau (4600～4800 m in elevation), is situated in permafrost region. Because of its special geography, harsh nature environment and complicated geological condition, water-proof/drainage and heat insulation for the tunnel are highly demanded. However, no successful experience for water|proof/drainage and heat insulation in such tunnels can be founded both at home and abroad, since the conventional methods cannot meet the needs of the tunnel construction. Hence, it becomes a typical and key structure for the design, construction technology and quality control. In this paper, the design characteristic of water-proof/drainage and heat insulation for plateau permafrost tunnel is put forward, which is laid between the initial lining supporting and final lining supporting with a structure of "compound water-proof plate plus heat insulation plate plus compound water-proof plate". In order to ensure good quality of the tunnel, heat insulation materials like non-woven cloth and /PVC compound water-proof plate, PU polyurethane plate, type TN-1 polyurethane adhesion agent, OP resin emulsion are selected as the lining material for water-proof/drainage and heat insulation. They are frequently tested and selected in accordance with the needs and requirements of construction of plateau permafrost tunnel. In order to get an ideal result of water-proof and heat insulation, with no nails, water-proof plates are double-seams welded with thermo-welder, and heat insulation plates are sticked together with type TN-1 polyurethane adhesion agent. As reasonable construction method and technology such as water-proof/drainage and heat insulation lining is adopted in this tunnel, the quality of tunnel construction is guaranteed.
  • An Outstanding Hydrologist for Glacier and Cold Regions ——Professor Yang Zhenniang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(1): 112-113. https://doi.org/10.7522/j.issn.1000-0240.2003.0018
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