25 June 2004, Volume 26 Issue 3
    

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  • Review and Prospects of Quaternary Glaciation Research in China
    LI Ji-jun, SHU Qiang, ZHOU Shang-zhe, ZHAO Zhi-jun, ZHANG Jian-ming
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 235-243. https://doi.org/10.7522/j.issn.1000-0240.2004.0041
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    Since the thirties of the last century, when Prof. Li Siguang (J S Lee) put forward his glacial theory on Mt. Lushan and other mountains in Eastern China, there have been many controversies in earth science world both at home and abroad. Were there really mountain glaciations developing in Eastern China during the Quaternary? This problem made many Chinese geologists and geographers in confusion. In the nineteen eightieth, Shi Yafeng and the authors of this paper had took a lot of field investigations and lab analyses and come to a conclusion quite different from Prof. Li and his followers. Their major points are: 1) Only in a few mountains in the east China distinct Quaternary glacial landform and deposits can be seen, such as the Taibai Shan in Shaanxi, the Changbai Shan in Jilin and the Mts. Yushan and Xueshan in Taiwan, while in other mountains claimed by Prof. Lee no evidence can be found; 2) The boulder clay and striated stones cited by Prof. Li as evidence of former glaciations have been identified mostly originated from debris flow; 3) Environment in east China had experienced dramatically changes during the Quaternary: The permafrost in north China had expanded southward by about 10 latitudes and reached the Great Wall, which means the mean annual temperature had lowered about 10～12℃. The ice-age "mammoth fauna" had roamed in north China and even reached to the estuary of the Yangtze River. The shoreline had expanded eastward about 600 km and the sea level had depressed 140 m compared with present. However, owing to the strengthening winter monsoon, climate of China was cold and dry in the ice-age, unfavorable for glaciations; Based on the data collected in the past decade, 3～5 glaciations have been identified in the mountainous regions of west China, all of which are dated to late and middle Pleistocene, but there is no positive evidence to support the hypothesis that an ice sheet had occurred on the Tibetan Plateau. The reason is that the Tibetan Plateau is very fresh, only 0.8 Ma since it uplifted up to (3000) m a. s. l. and became high enough for glacier development.
  • Variation of Glaciers Studied on the Basis of RS and GIS-A Reassessment of the Changes of the Xinqingfeng and Malan Ice Caps in the Northern Tibetan Plateau
    LIU Shi-yin, SHANGGUAN Dong-hui, DING Yong-jian, HAN Hai-dong, ZHANG Yong, WANG Jian, XIE Chang-wei, DING Liang-fu, LI Gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 244-252. https://doi.org/10.7522/j.issn.1000-0240.2004.0042
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    By applying remote sensing (RS) and geographical information system (GIS) techniques, an analysis of glacier changes during the last 30 year was made for Xinqingfeng and Malan Ice Caps, located at the central part of the Kunlun Mountains to the northern Tibetan Plateau. To this purpose, 1:100000 topographical maps, aerial photos, Landsat MSS and TM that were co-registered to map coordinate are used. Results indicate that the Xinqingfeng Ice Cap has experienced a general shrinkage and on the contrary the Malan Ice Cap just to the south of the former one has seen an increment in area from 1971 to 2000. Compared with previous study, it is found that the Xinqingfeng Ice Cap had an abrupt change in 1979. Before 1979 the area of the ice cap increased and after 1979 the ice cap retreated, with a relatively steady state during 1989-1994. As a matter of fact, area change of the Xinqingfeng Ice Cap was controlled to some extent by the variation of the Xinqingfeng Glacier in the southeast side of the ice cap and the West Xinqingfeng Glacier in the northwest side of the ice cap, the first and second largest glaciers around the Xinqingfeng Ice Cap. These two glaciers have experienced different variation patterns during the research period; the Xinqingfeng Glacier has been retreating all the time since 1971 with an accelerating trend after 1994, while the West Xinqingfeng Glacier retreated during 1971-1976 and after 1994 and advanced obviously during 1976-194. Variation of (δ18O), a good proxy of air temperature, recorded in the upper section of the Malan ice core reveals a warm period during 1950-1976, with mean temperature about 0.5℃ higher than that after 1976. The distinct terminus variations of the two glaciers could be attributed to different responses of the two glaciers to climatic change. The discrepancy in dynamic response may be controlled by different surface mass-balance gradients, which can be inferred from area-altitude profile and surface slopes of the two glaciers. In summary, no obvious climate-warming trend has appeared and less change in area has occurred in the two ice caps in the north part of the Tibetan Plateau during the past 30 years, although some of the large glaciers in this region have experienced remarkable fluctuation.
  • Variation of the Glacier No.1 at the Headwaters of the Ürümqi River in the Tianshan Mountains during the Past 42 Years and Its Trend Prediction
    JIAO Ke-qin, JING Zhe-fan, HAN Tian-ding, YE Bai-sheng, YANG Hui-an, LI Zhong-qin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 253-260. https://doi.org/10.7522/j.issn.1000-0240.2004.0043
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    The Glacier No. 1 at the headwaters of the Ürümqi Rive in the Tianshan Mountains (thereafter called Glacier No.1) originally was a valley glacier with two cirques. Owing to glacial retreat caused by global warming, the east branch of the glacier separated from the west branch in 1993. The length and area of the glacier decreased from the 2.2 km and 1.950 km2 in 1964 to 2.0 km and 1.733 km2 in 2000, respectively. The Glacier No. 1 has remarkably changed during the past 42 years, which can be seen from the following factors: mass balance of (-7976.0) mm, terminus retreat of 171.1 m, area decrease of 11.1%, mean thickness of 8.86 m and flow speed decrease of 39.3%. In addition, owing to the upward shift of ice formation zones, cold percolation-recrystallization zone disappeared. These reflect the general trend of climate change during the past 42 years. The observation for 42 years shows that for those glaciers, through which climate change can be reflected, the observation should be greatly highlighted. Based on the variation trend of glacial mass balance, it is predicted that the Glacier No. 1 would not make up the great mass deficits ((-7976.0) mm) and get surpluses unless it keeps continuous accumulation for 21 years with the extent of the biggest positive balance during the past 42 years ((+374.0 mm)). The previous researches show that the above condition hardly appears. Thus, it is conjectured that the retreating trend of the glacier will continuously go on for quite a long time, at least before the 2030s it is impossible to appear an apparent glacier advance. Based on the periodic characteristics of cold-warm and dry-wet circles in climate change as derived from tree ring data, it is presumed that it is now in the third warm period since the Little Ice Age. From 1955 up to now, the period lasts 45 years. If the warm period recurs with a periodicity of 62～67 years, it will last about 20 years from now on. Thus, it is expected that the glacier will keep retreating for more scores of years.
  • Glacier Variation in the Pumqu Basin Derived from Remote Sensing Data and GIS Technique
    JIN Rui, CHE Tao, LI Xin, WU Li-zong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 261-266. https://doi.org/10.7522/j.issn.1000-0240.2004.0044
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    To study the glacier variation in response to climate warming, the Pumqu Basin located in Tibet Autonomous Region was selected as the test area. The glacier outlines on the topographic maps in the 1970s were digitized. Then, 18 scenes of Advanced Space borne Thermal Emission and Reflection Radiometer images and 2 China-Brazil Earth Resources Satellite images were manually interpreted to derive new glacier distribution. The information for the new glacier inventory was obtained by the aid of high-resolution digital elevation model. The general trend of glacier variation in the recent 30 years was analyzed and computed supported by GIS. The result shows that the total glacier area in Pumqu Basin has decreased by 9% and the ice reserve has reduced by 8.4%. It is also confirmed that small glaciers are more sensitive to climate change.
  • Interdecadal Oscillation of Temperature in the Antarctic Peninsula in the Last 100 Years
    BIAN Lin-gen, WANG Jin-xing, LIN Xue-chun, LU Long-hua
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 267-274. https://doi.org/10.7522/j.issn.1000-0240.2004.0045
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    In this paper, by use of the monthly mean temperature data of 12 stations in the vicinity of Antarctic Peninsula, the temperature series during 1903-2000 is founded and the interdecadal oscillation of the temperature are discussed. The results indicate that there were three jumps in 1919-1923, 1947-1953 and 1976-1982 in the recent hundred years and the stable climate step between two jump points lasted for about 30 years. Annual mean temperature increased by 0.730℃ in an echelon during 1903-2000, the seasonal warming extent was dissimilarity, the maximum of warming was in the winter and the minimum of warming was in the summer. The decline trend of the index of ice concentration in the vicinity seas of Antarctic Peninsula was (-0.2053)\5(10a)-1, which in the summer half year (Dec-May) was much more obvious than that in the winter half year (Jun-Nov). There is a better negative relationship between the temperature and the ice concentration index in Antarctic Peninsula and its vicinity seas, with a correlation coefficient exceeding the significance level of 5% in summer, autumn and all the year round.
  • Geological Records of Climate and Environment Changes during the Holocene in the Nam Co Lake and Its Adjacent Areas
    WU Zhong-hai, ZHAO Xi-tao, WU Zhen-han, WU Xiao-chun, ZHOU Chun-jing, YAN Fu-hua, ZHU Da-gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 275-283. https://doi.org/10.7522/j.issn.1000-0240.2004.0046
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    The Nam Co Lake and its adjacent areas, including the Nam Co Lake in the north, the Nyainqêntanglha Range in the middle and the Damxung-Yangbajain basin in the south, are located in the central Tibetan Plateau. Based on the data of 14C, TL, OSL and U-series dating, the geological evidence from lacustrine deposits, sporo-pollen analysis of lake terraces T1, glacier fluctuation, paleo-cryoturbation, palaeosol and palaeo-carbonaceous sediments indicates that the variation of palaeovegetation, palaeoclimate and palaeoenvironment during the Holocene in the Nam Co Lake and its adjacent areas can be divided into the three stages: (1) During 11.8～8.4 ka BP Climate was relative warm with a few wet phases in the previous period. The lower section of the Nam Co Lake terrace T1 formed. Lake level fluctuation and carbonaceous sediments were not prominent in this stage. Vegetation was Artemisia steppe with a few Pinus and Betula trees around the lake, and alpine Cypressaceae meadow on Damxung s adjacent areas. (2) During 8.4～4.2 ka BP The Holocene Megathermal occurred in the stage. The warmest and wettest climate during the Holocene occurred. The middle-upper part of the Nam Co Lake terrace T1 formed. Vegetation was coniferous and deciduous broad-leaf mixed forest or forest-steppe with Pinus, Betula and Artemisia around the lake. At present, the similar vegetation is generally distributed in the area, where temperature and precipitation is higher than that around the lake. It indicates that the mean annual temperature and precipitation in the stage were respectively ～5℃ and ～100～200 mm higher than that at present around the lake. The shorelines show that the lake level rose to about 11.4 m higher than the lake level at present. In addition, black-gray carbonaceous fossil soil and river terrace T1, ～4 m above the river level, in Damxung-Yangbajain basin formed, and the extent and deposited rate of carbonaceous sediments increased. (3) Since 4.2 ka BP Climate was colder and drier than that during 8.4～4.2 ka BP. Vegetation was alpine Cypressaceae meadow in the mountains near Damxung. Level of the lake dropped and terraces T1 of the lake formed. The lake-level experienced 10～19 fluctuations between 0 m and 11.4 m above lake level. At the same time, the Xibu Glacier in the Nyainqê ntanglha Range had experienced 12 fluctuations. There were 5 fluctuations occurring during the Neoglaciation, 6 fluctuations during the Little Ice Age and 1 fluctuation since 1970 AD. Many cryoturbations, occurring in the late-Pleistocene and early-middle Holocene sediments, formed during Neoglaciation. Sand-wedge discovered in the cryoturbations of Riabu imply that the annual mean temperature was approximately 6℃ below zero during the Neoglaciation. Though climate was cold in the stage, it has become obvious warmer since 1970 AD. Owing to the glaciers in the Nyainqêntanglha Range prominently retreating, the level of the lake has risen about 2 m since 1970 AD.
  • Borehole Temperature at the Ice-core Drilling Site in the Muztag Ata Glacier, East Pamirs
    LI Zhen, YAO Tan-dong, TIAN Li-de, XU Bai-qing, WU Guang-jian, ZHU Guo-cai
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 284-288. https://doi.org/10.7522/j.issn.1000-0240.2004.0047
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    Borehole temperatures were measured at the ice-core drilling site ((7010) m a. s. l.) in the Muztag Ata Glacier in August 2003. The borehole-temperature profile shows a warm type at the end of summer. The ice temperature profile ((-26.17)～(-25.63)℃) and its minimum ((-26.17)℃) at this altitude are all the lowest among those measured in the mountain glaciers in the middle-low latitudes, and so is the temperature at the glacier bed. The temperature at the bedrock is (-25.73)℃, demonstrating that the Muztag Ata Glacier is frozen to its bed. From the measurement, the altitude effect on the ice temperature is very clearly. From (6250) m a. s. l. to (7010) m a. s. l., the lapse rates of ice temperature at 10 m depth, the minimum ice temperature and the temperature at bedrock are (-0.83)℃\5100 m-1, (-0.68)℃\5100 m-1 and (-0.79)℃\5100 m-1, respectively. These lapse rates are consistent with normal air temperature lapse rate ((-0.65)℃\5100 m-1).
  • Ice Core Records in the Past 2000 Years and Climate Warming during the 18th～20th Centuries
    YANG Mei-xue, YAO Tan-dong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 289-293. https://doi.org/10.7522/j.issn.1000-0240.2004.0048
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    Based on the temperature proxy data in the past (2000 years) recorded in the Guliya ice core and SSA, climate variation trends and effect of human activities are analyzed. It is found that there was a gradually warming trend in the past (2000 years). Such natural warming process seems already reaching the warmest phase at the present. However, it is also demonstrated that the human-induced warming has been significant since the industry revolution. Because of the superposition of the natural warming and the human-induced warming, the 20th century was the warmest 100 years in the past (2000 years).
  • Variation of Glaciers in Response to ENSO in the Mount Yulong
    ZHANG Zhong-lin, HE Yuan-qing, PANG Hong-xi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 294-297. https://doi.org/10.7522/j.issn.1000-0240.2004.0049
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    A correlation research between ENSO and its influence on the variation of precipitation, temperature and glacier in Lijiang Prefecture, Yunnan Province, is carried out by means of independence verification. It is found that there is a close correlation between ENSO and precipitation in the prefecture. While the Multivariate ENSO Index (MEI) is negative, precipitation will increase in the next year; when the MEI is positive, precipitation will reduce. There is a significant correlation between ENSO and temperature in the prefecture. In case that the MEI is negative, temperature will fall in the next year; when the MEI is positive, temperature will rise. A glacier accumulation index is designed using summer precipitation and temperature, and the correlation between ENSO and the index is analyzed. Some correlation between the MEI and the index of the next year is discovered, and the MEI change will affect glacier change. If the MEI is negative, glacier will advance; if the MEI is positive, glacier will retreat.
  • Paleoclimatic Change Derived from Natural Gamma-Logging Curve in Qaidam Basin and Its Relation to the Solar Insolation
    YUAN Lin-wang, LIU Ze-chun, CHEN Ye
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 298-304. https://doi.org/10.7522/j.issn.1000-0240.2004.0050
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    The astronomical theory of climate has provided a very powerful means for developing accurate time-scales. Using orbital tuning methods, a millennial-resolution time scale of Dacan-1 core is established over the past 2.85 Ma for a 3200-meter-long logging curve of lake sediments in the Qaidam Basin, Western China. By analyzing multi-dimension spectra and singular spectrum of the logging curve and other climatic records from deep-sea ((δ18O) curve of ODP677, ODP659、ODP758 sites and ice volume simulated curve) and Chinese loess deposits (grain size of the Baoji loess-soil sequence), a significant difference of periodic features is found between the Qaidam record and the deep-sea, the loess deposits. The climatic change reflected in the time-domain spectrum of the Qaidam record lagged those in the deep-sea and loess deposits by 3～4 ka. Furthermore, frequency-domain analyses and combination of singular spectrum illustrate that the signal of processional domain in the Qaidam record stronger than that in other deep-sea and loess records. This suggests that long-term climate change in the basin has been strongly influenced by variation of the processional-scale orbital insolation, as previously discovered in the low-latitude climatic regime. Deep-sea records and loess records have been strongly influenced by obliquity cycle change. It is pointed that the processional cycles in the logging curve over the past 2.85 Ma are quite different from those in deep-sea and loess deposits.
  • Quaternary Glaciations and Environment Change in the A’nyêmaqên Mountains
    DENG Xiao-feng, LIU Shi-yin, DING Yong-jian, SHEN Yong-ping, ZHAO Lin, XIE Chang-wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 305-311. https://doi.org/10.7522/j.issn.1000-0240.2004.0051
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    The A’nyêmaqên Mountains is located in the upper reaches of the Yellow River, where glaciers are well developing and also well developed in the Quaternary. Among the Quaternary Glaciations the Antepenultimate Glaciation in the mid-Pleistocene was the earliest and the maximum one. At that time, the ancient glacier termini reached (3600 m) a. s. l., the snow line was 801 m lower than that at present, and the glacierized area reached 381 km2, 16.2 times of that at present in the Qiequ River basin on the east slopes of the mountains. In the Antepenultimate and the Penultimate Galciations, the Dala Glacier in the Zhihedai River basin on the west slopes of the mountains had extended to (4100) m a. s. l., with the snow line 539 m lower than that at present and the glacierized area of 76.8 km2, 5.5 times of that at present. At that time, most of the mountains were covered by snow and ice with large-scale ice caps, indicating that climatic environment belonged to maritime type. The Penultimate Glaciation, the Last Glaciation, the Neoglaciation and the Little Ice Age after the Antepenultimate Glaciation were all influenced by the continuous uplift of the Tibetan Plateau, when precipitation was deceasing and glacier termini and snow line were increasing. For example, the glacier termini retreated from (3600 m) a. s. l. in the Antepenultimate Glaciation to (4500 m) a. s. l. at present on the east slopes, and retreated from (4100 m) a. s. l. in the Antepenultimate Glaciation to 4600 m a. s. l. at present on the west slopes. After the Antepenultimate Glaciation, the glacierized area decreased in large scale and climate gradually changed from maritime type to continental type. Climate in the mountains was going to be dry and warm after the later Last Glaciation and came into the great warm period in the Holocene.
  • Numerical Analysis of the Critical Height of Railway Embankment in Permafrost Regions of the Tibetan Plateau
    ZHANG Ming-yi, ZHANG Jian-ming, LAI Yuan-ming
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 312-318. https://doi.org/10.7522/j.issn.1000-0240.2004.0052
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    In permafrost regions, construction of a railway embankment may alter the original thermal equilibrium on the natural ground surface, resulting in the change of permafrost table under the embankment. In order to make sure that the permafrost table will not be service failure in the following 50 years after the embankment is built, the critical embankment height for coarse-grained soil in the permafrost regions on the Tibetan Plateau is calculated in this paper, considering the effect of globe warming. The mean annual air temperatures applied to the numerical analysis are (-6.5℃), (-6.0℃), (-5.5℃), (-5.0℃), (-4.5℃) and (-4.0℃), respectively, and the value of temperature rising is taken as 1.10℃ for the coming 50 years. The minimum embankment heights obtained from the analysis are 0.85 m, 0.92 m, 1.01 m, 1.18 m, 1.60 m and 2.66 m for different mean annual air temperatures mentioned above and the maximum embankment heights are 7.68 m, 7.55 m, 7.34 m, 7.00 m, 6.45 m and 5.85 m, accordingly. By summarizing the results of calculation and analysis, the following conclusions can be drawn: (1) Although mean annual air temperature is a key factor influencing the critical embankment height in permafrost regions on the plateau, the service life of the railway embankment must be taken into account; especially under the condition of globe warming, the lifespan of the railway is much more important to determine the critical height of the embankment. (2) On the condition that the service life of the railway embankment is 50 years, in the areas where mean annual air temperature is higher than (-3.5℃), the critical embankment height does not exist. Namely, however high the embankment is, the permafrost table under the embankment will fall anyway. If the lifespan of the railway embankment is lengthened or shortened, the critical mean annual air temperature will vary correspondingly. (3) No matter what the high or low embankment is constructed, the ground temperature under the embankment will rise and permafrost will be in a degradation situation. In other words, the construction of higher embankment may cause the permafrost table under the embankment to rise, but it is at the cost of consuming the cold preservation of permafrost underlain and cannot take the effect of permafrost protection actually, which has been confirmed by the field observation at the Qinghai-Tibetan Railway test sites.
  • An Experimental Research on the Thermal Conductivity Coefficient of Saline Soil
    DENG You-sheng, HE Ping, ZHOU Cheng-lin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 319-323. https://doi.org/10.7522/j.issn.1000-0240.2004.0053
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    It is found by indoor experiments that the thermal conductivity of saline soil has very close relation with salt component (salts) and salt content. At the same water content and the same dry bulk density of the same type of soil, for the same temperature above 0℃, the thermal conductivity coefficient of clay and sand soil increases with the enhancing sodium chloride salt content, but decreases with the enhancing sodium sulphate content. While for the same temperature below 0℃, whenever soils and salts, the thermal conductivity coefficient always decreases with increasing salt content, especially, the saline sand soil and the sodium sulphate soil decreases obviously. Under the same salt content, the thermal conductivity coefficient of sodium sulphate soil decreases with temperature when the temperature is under 0℃, and the thermal conductivity coefficient of sodium sulphate soil increases with temperature when the temperature is above 0℃. For the same salt content and temperature, the thermal conductivity coefficient of sodium sulphate soil increases with enhancing water content.
  • Modeling the Response of Runoff to Climate Change
    ZENG Tao, HAO Zhen-chun, WNAG Jia-hu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 324-332. https://doi.org/10.7522/j.issn.1000-0240.2004.0054
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    A single-direction coupling system is founded in this paper, including GCM s output data, down-scale model and distributed hydrologic model, and then the system is applied in Shanxi Province as a example to study the response of runoff to climate change. Data from the five GCMs (HADLEY, GFDL, CCCma, CRIRO and CCSR) are used in this paper. The hydrologic model calculates by not only distributed runoff generation and conflux, but also distributed evaporation. An integrated parameter (Kc) is used as a proxy of all factors, except climatic ones, which effect evaporation in each cell. The parameter is determined from observed data. A modified coefficient named (Ks) is used to express the effect of moisture to evapotranspiration. A software (CNT) is put forward to get an emulational river net from DEM. It is revealed from comparing the GCMs outputs with the observations in Shanxi Province that temperature can be fitted well, but precipitation from the GCMs is a qualitative one only, which can express a long-term variation trend. Through some necessary studies, a most possible changing trend of water resources in Shanxi Province is gained, which shows a decreasing trend in the next 50 years.
  • Effect of Water Allocation of the Heihe River on Plan Structure and Stable Development of the Ecosystem in the Linze Oasis, Gansu ——A Case Study in the Pingchuan Irrigation District in Linze County at the middle reaches of the Heihe River
    LI Qi-sen, ZHAO Wen-zhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 333-343. https://doi.org/10.7522/j.issn.1000-0240.2004.0055
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    Water allocation of the Heihe River and commercial utilization of water will exert a profound influence on adjustment of plant structure, water save and conceding the land in the Linze oasis. However, there are some problems that cannot be neglected, such as electing the course and time of water adjustment, effectively handling the contradiction between water supply and water demand, utilizing the water resource rationally and high-efficiently and so on. Especially, excessively exploiting groundwater and chasing short-term interests are aggravating to some extent owing to water resource shortage and the function of market economy. As a result, the range of water table fluctuation expands and the public welfare ecological construction and development are greatly restricted. In the interleaved zones of desert and oasis, there are many unsuitable or degradation phenomena after water allocation, with a deterioration trend in eco-environment and agricultural yielding condition.
  • Application of Local Modeling Method to the Monthly Runoff Prediction in the Upper Yellow River
    LAN Yong-chao, WANG Shu-gong, DING Yong-jian, MA Jian-hua ZHAO Chang-rui, CAO Chun-hui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 344-348. https://doi.org/10.7522/j.issn.1000-0240.2004.0056
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    The Longyangxia waterpower plant is the first large waterpower project in the upper Yellow River. Its reservoir possesses a capacity of 274×108 km3 and 95% of the inflow to the reservoir mainly come from the drainage above Tangnag located in the northeastern Tibetan Plateau between 95.5°～103.5°E and 32.5°～36.0°N, with a water collection area of 12.19×104 km2, accounting for 1/6 of the total area of the Yellow River Basin. However, the runoff in the upper Yellow River has been decreasing due to global warming and human activity since the end of the 1990s, which not only great affects the economy and people living in the upper Yellow River areas, but also restrains the economic development of whole Yellow River Basin. So accurate predicting the future runoff in the upper Yellow River is indispensable to adequate and reasonable exploitation of the water resources in the basin, as well as determining the amount of water supplied from other basin. In this paper, based on runoff series at the Tangnag Hydrometric Station and Local Modeling method, one of n-dimension and non-linear dynamical system forecast method, a monthly runoff-forecasting model is presented to predict the monthly inflow to the reservoir. Practice shows that the Local Modeling method possesses some marked advantages such as possessing favorable stability, possessing clear mathematics and physics meanings, being prone to operating and so on, as compared with some deterministic and non- deterministic forecast method. The model fits especially for forecasting monthly runoff in low-flow period and forecasting monthly runoff in flood season with satisfied veracity, if the effect of precipitation is calculated. So the model is thought to accord with the requirement of hydrology forecast criterion and becomes an available forecast.
  • An Experimental Study of Grassland Evapotranspiration in the Mountain Watershed of the Hei River Basin
    SONG Ke-chao, KANG Er-si, JIN Bo-wen, ZHANG Zhi-hui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 349-356. https://doi.org/10.7522/j.issn.1000-0240.2004.0057
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    Weighing microlysimeter method and two types of Penman-Moneith equations (PM) and Priestley-Taylor equation were used to calculate the actual evapotranspiration of mountain grassland in the Hei River Basin in the arid area of northwest China during summer of 2002. Meteorological variables including sub ground surface heat fluxes were measured in half an hour time step by data-logger integrated in ENVIS environmental measurement system. The evapotranspiration rate of the grassland is then calculated by PM equation, ASCE-PM equation, and Priestley-Taylor equation (PT). As compared to the measurement of the two Microlysimeters, the PM and PT methods obtained good agreement with only one Microlysimeter SW10, but two sets of results from two Microlysimeters are both compared well with the calculations from two PM equation and PT method during initial period of about 20 days, which have about 66 mm rainfall, after this time about 20 days, one Microlysimeter (SW10) continued to present good performance with the PM and PT equation, but the other set of Microlysimeter (N6) started have less evapotranspitation compared with the result of PM method and the other Microlysimeter. The factors for this lie on the influence of the plant species, and it is proposed that the installation of the Microlysimeters should be located on the grass land with the dominant plant species of the area. The energy balance calculation of the grass land indicates that, the mountain grass land has the cold and wet characteristics of underlying surface. When the soil wetness is maintained by enough precipitation, the energy is mainly consumed by evapotranspiration during the summer period.
  • Calculation of Discharge of Debris Flow Induced by Glacier Lake Outburst
    CHEN Xiao-qing, CHEN Ning-sheng, CUI Peng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 357-362. https://doi.org/10.7522/j.issn.1000-0240.2004.0058
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    Debris flow induced by glacier lake outburst is common in the Tibetan Plateau, which occurs abruptly and brings tremendous damages. Of special importance in the study are the discharge and its variation along the runway, including the most parameters for designing the measure against debris flow. This study presents a method for calculating the discharge, including the peak discharge at the outlet, Qmaxd=kQmax, and the maximal height of the flow near the outlet, Hmaxd=kHHmax, where kH=k·kG, k=1+(γd-γw)/(γs-γd), where γd is density of debris flow, γw is density of floodwater and γs is density of solid materials; and kG is a coefficient concerning the gully form. The calculation of Qmax and Hmax is induced by wave method under some hypotheses. In order to verify the validity of this calculation, a case study was carried out on the Midui Gully in Tibet Region. In stance, detailed calculation process of k and kG has been provided. It is revealed that the calculation agrees well with the field investigation in general trend. Furthermore, comparison with other formulas is made and much improvement can be seen. Because the calculation of kG has been simplified, it is not suited to use in other glacier lake outburst.
  • Estimation of Snow Water Equivalent in the Tibetan Plateau Using Passive Microwave Remote Sensing Data (SSM/I)
    CHE Tao, LI Xin, GAO Feng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 363-368. https://doi.org/10.7522/j.issn.1000-0240.2004.0059
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    Snow depth and snow water equivalent are the most import factors in the hydrologic model and climate model. So far, there is not an operational algorithm to estimate the snow water equivalent from passive microwave remote sensing data (SSM/I) in the Tibetan Plateau. In this study the SSM/I brightness temperature data in January 1993 are used to estimate the snow water equivalent SWE in the plateau. The frequencies of SSM/I data used to retrieve snow depth are 19 and 37 GHz in horizontal polarization. The results show that all available algorithms overestimate the snow depth in the Tibetan Plateau. In this paper the reasons of overestimation of snow depth from several aspects are analyzed, such as the water content of snow pack, large water bodies (e.g. lakes), and the abnormal field snow depth data. After eliminating some futile data (including the passive microwave brightness temperature values and snow depth data in the weather stations), an improved algorithm has been established to retrieve the snow depth from the difference of 19 and 37 GHz brightness temperatures in horizontal polarization. Here, snow density is obtained by a time function of fresh snow density. The snow depth and density were converted to the snow water equivalent, and are regarded as the ground truth. In finally, the TB vertically polarized differences of 19 and 37 GHz are regressed with the SWE. Using the statistical method, a simple and practical algorithm is developed to estimate the snow water equivalent from the differences of 19 and 37 GHz in vertical polarization.
  • Detecting Snow and Estimating Snowpack Parameters from NOAA16-AVHRR Data
    YAN Hao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 369-373. https://doi.org/10.7522/j.issn.1000-0240.2004.0060
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    Based on a spectral analysis of snow, soil, vegetation and cloud, in this paper it is indicates that the first two bands of traditional NOAA-AVHRR has trouble to distinguish snow from cloud, and the low reflectance of snow in the middle infrared spectral region can be used to distinguish snow from cloud. In this paper winter snow in northern China can be successfully detected by using newly 1.6 μm middle infrared band of NOAA16-AVHRR. Further, a method to estimate the snowpack parameters is presented, including snow time, snow area and snow depth. The difference of Band 1 and Band 3a for NOAA16-AVHRR is correlated with snow depth data from agri-meteorologic observation stations, and then an exponential fit equation of snow depth is built using curve regression. It is verified that the accuracy of the snow depth is good.
  • Monitoring Results of Glacier Changes in China Karakorum and Muztag Ata-Konggur Mountains by Remote Sensing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(3): 374-375. https://doi.org/10.7522/j.issn.1000-0240.2004.0061
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