25 October 2003, Volume 25 Issue 5
    

  • Select all
    |
  • Water Balance of Huahai Lake Basin during a Special Phase
    HU Gang, WANG Nai-ang, ZHAO Qiang, CHENG Hong-yi, CHEN Yong-sheng, GUO Jian-ying
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 485-490. https://doi.org/10.7522/j.issn.1000-0240.2003.0087
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Hydrological and energy-balance model, as a relatively mature method of paleo-precipitation restoration, has been widely applied. The development of this mode and the paleo-lake area and paleo-precipitation of a special phase in Huahai Lake basin restored by this model on the basis of field investigation and analysis are introduced in this paper briefly. It is found that the Huahai Lake reached its maximum area at about 4 300 a BP, when its area reached about 445 km2. Ignoring the effect of meltwater in its basin, annual precipitation is primarily estimated to be 151mm at about 4 000 a BP, 132% higher than that at present. However in this basin, meltwater accounts for about 30% at present. Subtracting the effect of meltwater, the lake area was 419 km2 at about 4 000 a BP. In this model, the effect of glacier does not be considered owing to the difficult in directly determining the volume of glaciers, but the influence of meltwater on lake coefficient, a decreasing from 0.0309 to 0.0291, is considered. Based on this, annual precipitation is estimated to be 146 mm, 100.6% higher than that at present. Meanwhile sensitivity analysis shows that cloudage is most sensitive to precipitation, followed by surface reflectivity, pressure of vapor and surface temperature. This provides the knowledge for researching the land degradation and desertification in this region, having an important significance for protecting and conducting ecological environments, which is one of the strategic emphases of developing Chinas west.
  • Quaternary Glaciations in Puruogangri——the Largest Modern Ice Field in Tibetan Plateau
    YI Chao-lu, LI Xiao-ze, QU Jian-jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 491-497. https://doi.org/10.7522/j.issn.1000-0240.2003.0088
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Puruogangri Ice Field, the largest modern ice field in the Tibetan Plateau with an area of over 400 km2 in total, is in the inner plateau. Although it is very difficult to reach, the scale of the ice field makes it important to study the Quaternary Glaciation in this inland area to determine whether there was a unified ice sheet in the Tibetan Plateau during the Quaternary period. Field observation showed that there are five moraine groups, termed Moraine I to V, of the teriminals moraines and lateral moraines from the teriminals of modern glaciers to the piedmont. Based on geomorphic locations, stratigraphic correlation, relative weathering, reworked degrees by wind action and ESR dating of erratic sands on the gobi, as well as through comparison with the Quaternary glaciations with numerical ages in western Chinese mountains, it is identified that these moraine groups represent the modern moraine, the Little Ice Age, Neoglacial, the late stage of the Last Glaciation and the early stage of the Last Glaciation, respectively. The granite boulders of Moraine V are scattered on the extensive peneplain, 6 km away from the mountain front. This suggests that the ancient glaciers in the west slopes of the ice field advanced to the piedmont during the late Pleistocene, but did not integrate with the ice in the mountains nearby to form a unified ice sheet.
  • Glaciers in the World and China: Distribution and Their Significance as Water Resources
    WANG Zong-tai, SU Hong-chao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 498-503. https://doi.org/10.7522/j.issn.1000-0240.2003.0089
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Glaciers are fine and clean fresh water resources. They are great in quantity, but are distributed inhomogenously in the world. All ice sheets concentrate in the Antarctica and Greenland, and the maximal part of mountain glaciers(84%)concentrates in Asian highlands and the frigid one in North America. Glaciers in China are accounting for 30% of glaciers in the middle-low latitudes. Among all countries in the middle-low latitudes, among all countries in the desert zones and among all countries being lack of water in the world, China is the biggest one that holds a great deal of glaciers in quantity and scale. In China most glaciers are distributed in the Qinghai-Xinjiang desert-oasis zone, including the Tarim River drainage, which is the inland drainage with the most amount of glaciers in the world, nourishing the Tarim glaciofluvial oasis. A policy of maintaining water resources and distributing expenditure is put forward in order to balance the development of oasis economy and the safety of ecological environment.
  • The Quaternary Glaciation in Rongbacha and Correlation with the Loess-Paleosol in Garz?
    XU Liu-bing, ZHOU Shang-zhe, LI Chang-ai, CUI Jian-xin, ZHAO Jing-dong, YE Yu-guang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 504-509. https://doi.org/10.7522/j.issn.1000-0240.2003.0090
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Rongbacha paleoglaciers of Garz? are located in the Hengduan Mountains, which lies in the eastern part of the Tibetan Plateau. They are the typical Quaternary glaciers in this region. Prof. Li Jijun ever named it as Rongbacha Ice Age. There is a relatively integrated glacier sequence from the Penultimate Glaciation to the Neoglaciation. Here, the technique of Electron Spin Resonance(ESR)is used to date the samples collected from this region. They formed at about 5.6 ka BP, the time between the Neoglaciation and the Last Glaciation Maximum, 16.3 ka BP, 18.7 ka BP, 43.7 ka BP and the Penultimate Glaciation, respectively. Thermoluminescent(TL)dating suggests the loess, which lies on the riverside terraces of the Yalong Rivre in Garz?, deposited from the early Last Glaciation. Besides, combining with the synthetical analysis on the proxies of the loess-paleosol sequence in Garz?, we can find that the glacier tills and the loess-paleosol in the Garz? almost deposited simultaneously. This indicates that they have been controlled by the same climate system since at least the last interglacial. At the Last Glaciation Maximum, the glacial tills in Rongbacha experienced a strike changing of nearly 90°, which was intimately related to the extremely arid and frigid climate at that time. In the interstadial of Last Glaciation, corresponding to MIS(marine isotope state)3b, the glacier scale in Rongbacha even exceeded that of the last Glaciation Maximum.
  • Discussion about the Glacier Extent and Advance/Retreat Asynchrony during the Last Glaciation
    CUI Zhi-jiu, ZHANG Wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 510-516. https://doi.org/10.7522/j.issn.1000-0240.2003.0091
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    It has been accepted that the glacier extent in the early stage was longer than that in the late stage in eastern Asia during the Last Glaciation. However, a new view has been proposed mentioning that there was a global temperature-decreasing phase in the middle stage(MIS 3b, 54～44 ka BP), when the glacier extent was larger than that in the Last Glacial Maximum due to the low temperature coming up against high moisture. It is revealed that the Quaternary glaciers not only evolved with localization, but also maybe with globalization. Meanwhile, the latest studies show a fact that the developmental characteristics of glaciers in high mountains or islands along the west Pacific Ocean is disaccorded with that in the inner land. Therefore, an important conclusion can be drawn that the glacier development exhibits a regional difference. The study validates the reasonableness of the asynchronous advance theory, and makes sure that both the synchronous and asynchronous advance/retreat of glaciers existed from 30 ka BP to 10 ka BP.
  • A Record of Drought and Flood Series by Tree-Ring Data in the Middle Section of Qilian Mountain Since 904 A.D.
    KANG Xing-cheng, CHENG Guo-dong, CHEN Fa-hu, GOU Xiao-hua
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 518-525. https://doi.org/10.7522/j.issn.1000-0240.2003.0093
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The standardized(STD)chronology was established from tree-ring data of Sabina Przewalskii in the middle part of the Qilian Mountains. The correlation was analyzed between the tree-ring index and the precipitation in weather stations, near which the tree ring is sampled. The results showed that there were 31 dry spells and 30 wet spells in the past 1100 years, of which 1540～1590 A.D. was the longest dry period, lasting 6o years, and 1240～1270 A.D. and 1860～1890 A.D. were the longest wet periods, lasting 40 years respectively. There were 17 durations of dry period over 10 years, and 12 durations of wet period over 10 years. With regard to the century time scale, the 16th Century was 100 years of drought, with 80 years being lack of rain. The 13th Century, as well as the 19th Century, was 100 years of wet, with 60 years in spate. At the same time, another characteristic of precipitation variation in these mountains is more abrupt change. There have had 35 abrupt changes since 904 A.D., about 30 years on the average. There were 16 shifts from drought to wet, and 19 shifts from wet to drought. There were 9 abrupt changes in the 11th Century, 2 abrupt changes in the 15th and 16th Centuries. In the 20th Century there were 3 abrupt changes. Precipitation in these mountains frequently changed in the 11th Century, and less changed in the 15th and 16th Centuries. In the 20th Century precipitation changed frequently.
  • Relationship between Northern Cyclones and Climate Change in Northwest China
    WANG Sui-chan, LI Dong-liang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 526-532. https://doi.org/10.7522/j.issn.1000-0240.2003.0094
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on surface station meteorological data from 1957 to 1990 the number of the Northern Cyclones is worked out. Some statistical characteristics between the Northern Cyclone and the relationship of temperature and precipitation in Northwest China are analyzed. The results show that the frequency of the North Cyclones was ascending in the last of the 1950s, descending remarkably from the 1960s to the 1970s, especially in the winter and in the autumn, and the relationship between the Northern Cyclones and the weather in Northwest China is high. Especially, the frequency of the North Cyclones in spring has an important function on precipitation in the flood season in Northwest China. Furthermore, the change in Northern Cyclones has remarkable relationship with sandstorms in North China, and the descending frequency of Northern Cyclones plays an important role in descending sandstorms.
  • Research on Ice Core Record fromm King George Island,West Antarctica: Dating, Particles and Ion Elution
    ZHANG Xiao-wei, KANG Jian-cheng, ZHOU Shang-zhe
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 533-540. https://doi.org/10.7522/j.issn.1000-0240.2003.0095
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As a temperate glacier, melting takes place and causes migration of water and chemical constituents in the snow and ice. The upmost 20 m ice core(about 5 years)of the Big Dome, King George Island, West Antarctica, can be dated by physical and chemical seasonal variations. Based on high accumulation and other climate condition, it is assumed that there is a linear relation with a constant k between the accumulation on the top of ice cap and precipitation at the shore of King George Island. By compared the top annual layers with corresponding precipitation during the 5years, it is found that k=3.98. With the value, the 45 m ice core is dated to be totally 15 years. Again it is revealed that the particle profile in the 45 m ice core has not been affected by melting and can be used to reconstruct paleo-environment. There are two exceptional peaks located at about 20 m and 38 m depths, respectively. Applying the dated result, the two particle peaks are determined to correspond to the Deception Island eruption(1986～1987)and Seal Nunataks volcano eruption(1980). Major ions concentrations in both ice cores of the Big Dome and Small Dome reduce with depth in general, which indicate that ion elution process occurs during melting. It is found that the average major ion concentrations of five depth segments in both ice cores reduce as exponent functions C=C0×e-h, where h is the depth, C0 is the initial concentration, C is the concentration at depth h. According to the coefficient λ, the preferential ion elution orders are determined as SO42- >Mg2+>Ca2+>K+>Cl->Na+>NO3->Br- on the Big Dome and Mg2+>Ca2+>SO42->K+>Cl->Br->Na+ on the Small Dome. The location difference of major ions within the ice crystal lattice is the main cause of the preferential elution.
  • Frozen Soil Parameterization Scheme Coupled with Mesoscale Model
    ZHANG Yu, SONG Min-hong, LÜ Shi-hua, SUN Shu-fen
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 541-546. https://doi.org/10.7522/j.issn.1000-0240.2003.0096
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A simple frozen soil parameterization scheme is developed. It can be coupled with mososcale model system that coupled NCAR Land Surface Model(LSM), which considered the primary features of frozen soil as follows: 1)phase change in soil column is the source/sink term in energy budget, and soil ice content is set as a prognostic variables and can be solved by combination of freezing point depression equation and soil matrix potential relation; 2)a new parameterization of thermal conductance(J75)is adopted to replace the former one(Farouki, 1981), which can be more accurately described under frozen soil condition; 3)effect of soil ice on liquid water movement is considered and it also affects the partition of surface between infiltration and runoff. The simulation has been conducted over high latitude regions, including North China, Mongolia and East Siberia in October, when seasonal frozen soil is forming in the north hemisphere. The results indicate that the model can reasonably simulate frozen soil distribution. It is found that the simulated ice content and ground heat flux are related to the soil type and frozen depth. The simulation of sea level pressure field and air temperature field, therefore, can be evidently improved.
  • A Model of Water Flux in Frozen Fringe Based on Traveling Wave Solution
    QIU Chun-han
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 547-551. https://doi.org/10.7522/j.issn.1000-0240.2003.0097
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As to the phenomenon of secondary frost heave, the behavior of water flux in frozen fringe is one of the major subjects to study. A new mathematical model in frozen fringe is built in this paper based on mass and heat equilibrium laws with the special situation that traveling wave solution exists. Some necessary assumptions are made and a group of equations with boundary conditions are obtained. The model is discussed for ice segregating and for frost penetration, respectively. The results are relatively clear for lens formation that coincides with some engineer calculation formula. Efforts have also been made on the numerical tests of water flux intake in an open system for the model with given temperature field under some hypotheses. In the first stage, the formula is adopted of penetration and in the second one the formula is used of lens formation. The results can reflect the changing trend of water flux intake in real situation on the whole.
  • Synchronous Measurement of Land Surface Processes in Typical Vegetation Landscape Zones in the Hei River Basin
    SONG Ke-chao, KANG Er-si, LAN Yong-chao, ZHANG Xiao-you, ZHANG Zhi-hui, JIN Bo-wen, ZHANG Ji-shi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 552-557. https://doi.org/10.7522/j.issn.1000-0240.2003.0098
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    On the review of some international research projects related to land surface processes and on the context that sustainable development of environment-resource-economy system are restricted to scarce water resource in arid area in northwest China, the researches presented in this paper are aimed to understand the processes related to water and energy cycle and ecological process at different vegetation landscape zones of inland river basins. Understanding of the land surface hydrological processes of energy and water exchange can help us accomplish efficient water resource management, such as water resource allotment, desert vegetation protection, and find the equivalent value which different ecosystem can supply to us at different scenes in inland river basin. Therefore synchronous measurement and experiment on land surface processes, energy and water fluxes in the soil vegetation atmosphere system in typical vegetation landscape zones are expected to find a key for these problems. In the present study, three synchronous measurement fields were set up in upper-stream mountain vegetation zone, oasis-desert transitional zone between desert and oasis, the natural oasis zone at the downstream riparian tamarisk forest of the Hei River Basin in the arid area of northwest China. The three fields of measurement and experiment represent typical vegetation landscape zones in a inland river basin. Three environment measurement systems of ENVIS, which can measure standard meteorological factors and other ecological factors were installed in the three typical vegetation landscape zones in Hei river basin. The comparative analysis is carried out on the measurements of SVAT system in three vegetation landscape zones, and theories and approaches to parameterize the water and energy fluxes in SVAT system at the three measurement locations are discussed. The preliminary results obtained indicate that the forest-grassland-shrubbery zone in mountain vegetation landscape zones is a cold and wet surface, and the oasis-desert transitional zone in middle river is a relative wet but dry land surface, while the riparian tamarisk forests and their adjacent places in the downstream area are drier and hotter land surface. In the aspect of carbon cycle and sequestration, the forest-grassland-shrubbery is a sink for carbon sequestration according to preliminary research, and there have distinct discriminations between the middle stream and the downstream area.
  • A Study of Estimation of Evapotranspiration on Grass Land in the Mountains of Hei River Basin
    WANG Shu-gong, KANG Er-si, JIN Bo-wen, WANG Xin-ping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 558-565. https://doi.org/10.7522/j.issn.1000-0240.2003.0099
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Estimation of evapotranspiration is an important aspect in the research and computation of water balance and runoff processes in the inland river basins of the arid area of northwest China. Especially, the development of runoff models in the inland river basins meet problems in the estimation of evapotranspiration. However, because of lack of the measurement and researches on evapotranspiration in the inland river basins, there are still not the effective methods to estimate evapotranspiration in accordance with the characteristics of climate, hydrology, ecology and environment. This paper is intended to investigate the estimation methods of grass land evaportranspiration in the mountain area of Hei River Basin in the arid area of northwest China. Based on the preceding researches, this paper puts forward two estimation methods of evapotranspiration: one is based on Penman-Monteith equation, another is based on Priestly-Taylor equation. Then this paper makes a comparison between the results of the two methods and the result of SHAW model. The comparison shows that the two methods suggested in this paper obtain the similar results in good fitness to the results simulated with SHAW model. Contrasting to SHAW model, the two methods in this paper require less parameters, especially the method based Priestly-Taylor equation is more convenient to apply in the mountains of the inland river basins. Because fewer observations about meteorology and hydrology, the two methods recomended in this paper are good choice in the estimation of evapotranspiration in the mountain area of the Hei River Basin.
  • Simulation of Water Resources Transformation in the Midstream Area of the Hei River Basin
    CHEN Ren-sheng, KANG Er-si, YANG Jian-ping, ZHANG Ji-shi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 566-573. https://doi.org/10.7522/j.issn.1000-0240.2003.0100
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on 1:100 000 geographical map, TM image, monthly precipitation and air temperature from 35 hydro-meteorological stations, monthly evaporation from 21 stations and ground water level data from 97 wells during 1990 to 1992, this paper is intended to develop a distributed water balance model for the midstream area of the main branch of the Hei River. The research area covers 1.795×104km2, the basic unit size for computation is 930 m×930 m, and the time step is one month.. The results of simulation show that, in the total study area during 1990 to 1992, the average precipitation is 193.1mm, the average inputted runoff to the area is 127.8 mm, and the inputted deep ground water is 10.0mm. The total inputted water resource to the area is 330.9 mm, the evapotranspiration is 294.5mm, the output runoff is 36.3 mm, and the change of the water resource storage is 0.1 mm. Thus the total outputted water resource is 330.8 mm. The simulated total runoff amounts for 19.564×108m3 during 1990 to 1992, which is 0.04×108m3 more than the observed value. The most precipitation and 71.6% of the inputted runoff to the area are lost by evapotranspiration.. The simulated results show that, the precipitation is relatively more in the mountain area or the area near the mountains, therefore the natural vegetation grows rather well there. On the other hand the precipitation in the gobi and desert area is very less. The type and distribution of natural vegetation are highly related to precipitation. Therefore, precipitation is the control factor affecting the growth of the natural vegetation in the midstream area of the Hei River Basin.. The groundwater of the study area shows an increment during 1990 to 1992, but it increased During 1990 to 1991, while decreased in 1992. Generally, the groundwater level decreases in March, May and July, when the groundwater is pumped out for irrigation. The groundwater level increases in the region with high vegetation coverage, while decreases in the gobi and desert near the mountains and in the cities.. Evapotranspiration is much more in the forests, high coverage meadow and farmland, while it is very less in the gobi and desert area, and it is the most in the oasis forest. For herbal vegetation, the evapotranspiration is proportional to the vegetation coverage.
  • A Brief Introduction to Application of the TRIME-TDR Technology in the Field Experiment of the Hei River Basin
    ZHANG Zhi-hui, KANG Er-si, JIN Bo-wen, SONG Ke-chao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 574-579. https://doi.org/10.7522/j.issn.1000-0240.2003.0101
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    TDR has been applied to the field experiments in many research projects of the Hei River Basin extensively as an effective technology to measure the soil moisture. This paper is intended to briefly introduce the development, principles and types of TDR, then mainly to analyze the characteristics, advantages and influence factors of the TRIME-TDR which is the patent product of IMKO Company in Germany. The TRIME-TDR measurement system has been installed in the different vegetation landscape zones of the Hei River Basin. As compared with the other soil moisture measurement instruments such as the capacitive moisture measurement instrument, neutron moisture instrument and traditional TDR, the TRIME-TDR has the advantage of reducing the influence of the electricity conductivity, having the large measurement range of soil moisture with various sensors, suitable for the measurement of the inhomogeneous soil and easy to handling in the field investigations. From our experience of the utilization of TRIME-TDR in the field measurement, some suggestions and recommendations are presented for the better and effectively utilization, installation and maintenance of TRIME-TDR measuring system.
  • Eco-hydrological Function of Mountain Vegetation in the Hei River Basin, Northwest China
    JIN Bo-wen, KANG Er-si, SONG Ke-chao, LIU Xian-de
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 580-584. https://doi.org/10.7522/j.issn.1000-0240.2003.0102
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The altitude dependency of different mountain vegetation landscape zones are diagramed by field investigations in the mountain watershed of the Hei River Basin in the arid area of northwest China. Based on the structure and characteristics of soil vegetation atmosphere system, the eco-hydrological function of mountain forests, which are called the water restraint forests, is analyzed from the stratification of canopy layer, moss-residue layer and soil layer. The canopy layer intercepts 34.7% of rainfall averagely and brings nutrient to the soil about 61.04 kg·hm-2·a-1 by eluviation. The moss-residual layer can hold water up to 1.25×105kg·hm-2, that is equivalent to about 12.5 mm depth of water. The volume content of soil water in the surface soil layer of the moss-residual layer is relative high and has less variation. Therefore, the moss-residual layer detains some proportion of precipitation and possesses good water restraint ability. The infiltration rate of forest soil is averaged with 162 mm·min-1, which is about 8～170 times of that in grassland outside the forests. The evaporation of forest soil is only about 34.2% of that in grassland’s by the forests. It is observed that even a rainstorm of 94.5 mm does not generate surface runoff in the forest covered area. It is concluded that the mountain forests possess unique hydrological function of water and soil conservation in the mountain vegetation zone at the upper stream of the Hei River Basin.
  • A Study on the Stem Sap Flow of Populus euphrtaicr and Tamaris spp. by Heat Pulse Technique
    ZHANG Xiao-you, GONG Jia-dong, ZHOU Mao-xian, SI Jian-hua
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 585-590. https://doi.org/10.7522/j.issn.1000-0240.2003.0103
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The E jina natural oasis is located at the down stream alluvial plain of the Hei River and belongs to the desert vegetation zone of the inland river basins in the arid area of northwest China. Since 1950s, the desert plants at the down stream area of the Hei River, such as Populis euphrtaicr, Elaeag nusangastifolia, Tamarix spp and Haloxy lonammosdendron, have been reduced by about 30% to 70%. Therefore, it is necessary to investigate the regularities of water consumption of the desert plants. In this paper, the heat pulse technique was applied to study the stem sap flow of Populus euphrtaicr in and Tamaris spp. in the down stream desert vegetation zone of the Hei River Basin during the vegetation growing season from May to October of 2002. The results achieved show that, in the natural conditions, the ratio of sap flow of Populus euphrtaicr is 0.34 L·cm-2·d-1, while that of Tamaris spp. is much less, only 0.15 L·cm-2·d-1. The diurnal variation of sap flow velocity shows multi-peaks characteristics, and it has the sudden drop phenomenon with the least value in the afternoon. During the night, the sap flow still exists to keep the water supply for the plants. The amount and velocity of stem sap flow increase with the cross section of the plants. During the growth season, the water consumption of Populus euphrtaicr in with the diameter of 21 cm and 15 cm of the cross section is 23.30 L·d-1 and 19.25 L·d-1 respectively, while that of Tamaris spp. with the diameter of 5 cm and 4 cm of the cross section is 0.62 L·d-1 and 0.37 L·d-1 respectively. During the growth season from May to October, the total evapotranspiration is 3 419.4L for Populus euphrtaicr in and only 63.9 L for Tamaris spp.
  • Characteristics of Spatial Heterogeneity of the Desert Riparian Forest in the Hei River Basin
    HE Zhi-bin, ZHAO Wen-zhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 591-596. https://doi.org/10.7522/j.issn.1000-0240.2003.0104
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Geo-statistical techniques are used to evaluate spatial characteristics of the desert riparian forest at the down stream of the Hei River in the arid area of northwest China. Spatial structures of different vegetation populations were characterized by means of nugget, range and sill parameters of spherical or exponent model variograms. Model variograms reveal that different vegetation populations have distinctive spatial properties, which are quantified effectively by the parameters of the models. Model variograms were fitted to the experimental variograms, which were calculated from width of plant bosom and vegetation coverage measured at 1 sampling transect of 2 000 m×5 m, 5 sampling transects of 500 m×5 m and 3 sampling transects of 200 m×2 m. Transects of 2 000 m×5 m were laid out between river and desert, the other transects were laid out in different vegetation populations. Desert riparian forests in the Hei River Basin show the spatial distributive pattern of patchiness, the main populations are older Populus euphratica; younger Populus euphratica; Tamarix chinensis; Sophora alopecuroides and so on. The maximum model variogram range was 55 m for all populations, suggesting that transects must at least be such long to classify the riparian forests unambiguously into the populations currently recognized. Experimental variograms were calculated for all plants in each of four mapped vegetation populations. The Tamarix chinensis and Sophora alopecuroides populations have distinctively long range, but the spatial heterogeneity of Populus euphratica populations has multiscale changes. At the scale of community, spatial heterogeneity of vegetation increases and also has multiscale changes. According to analyses, the spatial heterogeneity of community has distinctive change at the scale of 400 m, and this is also the scale of population patchiness turnover. These findings support use of high-resolution remote sensors and geostatistics for determining vegetation community structure of desert riparian forests. Spatial pattern information produced by these methods could improve broad scale vegetation classifications produced by low-resolution remote sensing systems.
  • Characteristics of δ13C Values of Desert Plants and Their Water Utilization Efficiency Indicated by δ13C Values in the Desert of Central Hexi Corridor Region
    SU Pei-xi, CHEN Huai-shun, LI Qi-sen
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2003, 25(5): 597-602. https://doi.org/10.7522/j.issn.1000-0240.2003.0105
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Temperate desert plants always grow in the high temperature, arid and water deficit environment throughout a year. Different plants have different photosynthetic organs to adapt extreme environmental conditions. The purpose of this paper is to probe into the characteristics of δ13C of leaves and assimilating shoots and into water use efficiency(WUE)of desert plants, and to provide a theoretical basic for protecting and fostering natural ecosystems of desert regions. The results achieved by the present study will serve restoring the degraded vegetation and maintaining the stability of protective eco-systems in the peripheric districts of oases. The δ13C values of leaves and assimilating shoots of desert plants in the desert of central Hexi Corridor region(39°19′～39°21′ N, 100°02′～100°21′ E, 1 368 ～ 1 380 m a.s.l.)were analyzed and discussed in this paper. δ13C of leaves and assimilating shoots and δ13C air were analysed with MAT-252 mass spectrometer. The characteristics of δ13C of leaves or assimilating shoots and WUE of plants indicated by δ13C values in this region were also studied. At the same time, comparative studies of shelterbelt arborous species and some oasis crops were also carried out. The results indicate that the δ13C values of assimilating shoots of Haloxylon ammodendron and Calligonum mongolicum are-14.31‰ and-14.8‰ respectively, and stable carbon isotope discrimination(Δ)is between 5‰～6‰. The δ13C values of leaves for Caragana korshinskii, Nitraria sphaerocarpa, Hedysarum scoparium and Reaumuria soongorica are-25.75‰,-25.79‰,-26.38‰ and-28.05‰ respectively, while Δ is between 16‰～20‰.. The long-term water use efficiency of several desert plant species can be ranked in the general order: H. ammodendron≈C. mongolicum>C. korshinskii≈N. sphaerocarpa≈H. scoparium>R. soongorica.
Copyright © Journal of Glaciology and Geocryology, All Rights Reserved.
Tel: 0931-8260767　
E-mail：edjgg@lzb.ac.cn
Total visitors: 　 Visitors of today: 　 Now online:
Powered by Beijing Magtech Co. Ltd,.