共查询到20条相似文献，搜索用时 125 毫秒
1.
Glacier meltwater change in the north‐eastern edge of the Tibetan Plateau is greatly important for the projection of the impact of future climate change on local water resource management. Although the glaciated area is only approximately 4% of the Upper Reach of the Shule River Basin (URSRB), the average glacier meltwater contribution to river run‐off was approximately 23.6% during the periods 1971/1972 to 2012/2013. A new glacier melting module coupled with the macroscale hydrologic Variable Infiltration Capacity model (VIC‐CAS) was adopted to simulate and project changes in the glacier meltwater and river run‐off of the URSRB forced by downscaled output of the BCC‐CSM1.1(m), CANESM2, GFDL‐CM3, and IPSL‐CM5A‐MR models. Comparisons between the observed and simulated river run‐offs and glacier area changes during the periods 2000/2001, 2004/2006, 2008/2009, and 2012/2013 suggest that the simulation is reasonable. Due to increases in precipitation, the annual total run‐off is projected to increase by approximately 2.58–2.73 × 108 m3 in the 2050s and 0.28–1.87 × 108 m3 in the 2100s compared with run‐off in the 2010s based on the RCP2.6 (low greenhouse gas emission) and RCP4.5 (moderate greenhouse gas emission) scenarios, respectively. The contribution of glacier meltwater to river run‐off will more likely decrease to approximately 10% and less than 5% during the 2050s and 2100s, respectively. 相似文献
2.
Glacier retreat and its impact on summertime run‐off in a high‐altitude ungauged catchment 
下载免费PDF全文
下载免费PDF全文 Glaciers are significant freshwater storage systems in western China and contribute substantially to the summertime run‐off of many large rivers in the Tibetan Plateau. Under the scenario of climate change, discussions of glacier variability and melting contributions in alpine basins are important for understanding the run‐off composition and ensuring that water resources are adequately managed and protected in the downstream areas. Based on the multisource spatial data and long‐term ground observation of climatic and hydrologic data, using the remote sensing interpretation, degree‐day model, and ice volume method, we presented a comprehensive study of the glacier changes in number, area, and termini and their impacts on summertime run‐off and water resource in the Tuotuo River basin, located in the source region of the Yangtze River. The results indicated that climate change, especially rising temperature, accelerated the glacier melting and consequently led to hydrological change. From 1969 to 2009, the glacier retreat showed an absolutely dominant tendency with 13 reduced glaciers and lost glacier area of 45.05 km2, accompanied by limited growing glaciers in the study area. Meanwhile, it indicated that annual glacial run‐off was averagely 0.38 × 108 m3, accounting for 4.96% of the total summertime run‐off, followed by the supply from precipitation and snowmelt. The reliability of this magnitude was assessed by the classic volume method, which also showed that the water resources from glacier melting in the Tuotuo River basin increased by approximate 17.11 × 108 m3, accounting for about 3.77% of the total run‐off over the whole period of 1969–2009. Findings from this study will serve as a reference for future research about glacier hydrology in regions where observational data are deficient. Also, it can help the planning of future water management strategies in the source region of the Yangtze River. 相似文献
3.
Changes in the hydrological regimes of Arctic rivers could affect the thermohaline circulation of the Arctic Ocean. In this study, we analysed spatiotemporal variations in temperature and precipitation in the Ob River Basin regions during 1936–2017 based on data from the Global Precipitation Climatology Center. Changes in discharge and response to climate change were examined based on monthly observed data during the same period. It is indicated the Ob River Basin experienced significant overall rapid warming and wetting (increased precipitation) in the study period, with average rates of 0.20°C (10 year−1) and 5.3 mm (10 year−1), respectively. The annual spatial variations of temperature and precipitation showed different scales in different regions. The discharge in spring and winter significantly increased at a rate of 384.1 and 173.1 m3/s (10 year−1), respectively. Hydrograph separation indicated infiltration and supported that deep flow paths increased the contribution of groundwater to base flow. Meanwhile, the variation of the ratio of Qmax/Qmin suggested that the basin storage and the mechanism of discharge generation have significantly changed. The hydrological processes were influenced by changes of permafrost in a certain in the Ob River Basin. An increase in the recession coefficient (RC) implies that the permafrost degradation in the basin due to climate warming affected hydrological processes in winter. Permafrost degradation affected the Qmax/Qmin more significantly in the warm season than RC due to the enhanced infiltration that converted more surface water into groundwater in the cold season. The impact of precipitation on discharge, including surface flow and base flow, was more significant than temperature at the annual and seasonal scales in the Ob River Basin. The base flow was more obviously influenced by temperature than surface flow. The results of this study are significant for analyses of the basin water budget and freshwater input to the Arctic Ocean. 相似文献
4.
Hydrological regimes in the Yellow River have changed significantly because of climate change and intensive human interventions. These changes present severe challenges to water resource utilization and ecological development. Variation of run‐off, suspended sediment load (SSL), and eight precipitation indices (P1: 0–12 mm·day?1, P12: 12–25 mm·day?1, P25: 25–50 mm·day?1, P50: P ≥ 50 mm·day?1 and corresponding rainfall day: Pd1, Pd12, Pd25, Pd50 day year?1) in three critical parts of the Yellow River basin (source region: SRYRB, upper reaches: URYRB, middle reaches: MRYRB) were investigated for the period from 1960 to 2015. The results show that run‐off and SSL significantly decreased (P < 0.01) in the URYRB and the MRYRB, whereas their decline in the SRYRB was insignificant (P > 0.05). Moreover, run‐off in the URYRB had one change point in 1987, and SSL in the URYRB as well as run‐off and SSL in the MRYRB had two change points (in the 1970s and the 1990s). Over the same period, only Pd1 and Pd12 in the SRYRB showed significant increasing trends, and an abrupt change appeared in 1981. The optimal precipitation indices for assessing the effects of precipitation on run‐off and SSL in the URYRB and MRYRB were Pd50 and P12, respectively. A double‐mass curve analysis showed that precipitation and human activities contributed to approximately 20% and 80% of the reduction in run‐off, respectively, for both the SRYRB and the MRYRB. However, the contribution rate of precipitation and human activities on SSL reduction was approximately 40% and 60% in the URYRB and 5% and 95% in the MRYRB, respectively. Human activities, primarily soil and water conservation measures and water extraction (diversion), were the main factors (>50%) that reduced the run‐off. However, the dominant driving factors for SSL reduction were soil and water conservation measures and reservoir interception, for which the contribution rate was higher than 70% in the MRYRB. This work strengthens the understanding of hydrological responses to precipitation change and provides a useful reference for regional water resource utilization. 相似文献
5.
Impacts of climate change on the discharge and glacier mass balance of the different glacierized watersheds in the Tianshan Mountains,Central Asia 下载免费PDF全文
下载免费PDF全文 The Tianshan Mountains represent an important water source for the arid and semi‐arid regions of Central Asia. The discharge and glacier mass balance (GMB) in the Tianshan Mountains are sensitive to changes in climate. In this study, the changes in temperature, precipitation, and discharge of six glacierized watersheds of Tianshan Mountains were explored using non‐parametric tests and wavelet transforms during 1957–2004. On the basis of the statistical mechanics and maximum entropy principle model, the GMB at the watershed scale were reconstructed for the study period. The discharge and GMB responses to climate change were examined in different watersheds. The results showed that regional climate warming was obvious, especially after 1996. The warming trend increased gradually from east to west, and the increase in temperature was greater on the north slope than on the south slope. The changing trends in precipitation increased from eastern region to central region, and then, the trend decreased in the western region, although the value was higher than that in the eastern region. The discharge presented significant periods of 2.7–5.4 years and increased from east to west. Significant periodicity indicated that the discharge in the different watersheds exhibited obviously different patterns. The GMB losses were larger in south and east than in north. The large glaciers had more stable interannual variations in discharge, and large fluctuations in discharge will be observed as the glacier areas shrink. Precipitation was the dominant factor for discharge during the study period, although the influence of increasing temperatures on hydrological regimes should not be neglected in the long term. Systematic differences in discharge and the GMB in glacierized watersheds in response to climate change are apparent in the Tianshan Mountains. 相似文献
6.
Considering the highly stochastic nature of the hydrological process, wavelet transform was used to analyse the characteristics, trends and causes of variations in annual run‐off (1917–2006) into Tianjin in the Haihe River Basin. Run‐off was steadily declining due to climate change and human activity and a significant decrease in run‐off along the time series was discovered around the 1960s; however, the change in precipitation was insignificant. The time series of run‐off was heavily influenced by a nonlinear feature and mainly influenced by the natural climate before the 1960s, but after the 1970s the change remained steady, with an annual run‐off that fluctuated between 0·2 and 48·4 mm and was maintained at a low level (9·3 mm). The main cause of the run‐off decline in the 1960s was that more than 1900 reservoirs with a total holding capacity of up to 83 mm were constructed in the upper and middle reaches, which controlled 85% of the total run‐off. These projects have played an active role in the reservoir action and water conservation since they were implemented. At the beginning of the 1980s, the demand for water resources increased with the rapid growth of the population and the large‐scale development of industry and agriculture in the Haihe River Basin, which caused a reduction in run‐off into Tianjin. Overall, the hydrological effects of water storage projects regulating river run‐off were beneficial to flood control, but might cause a serious reduction in river run‐off into Tianjin and the lower reaches of the basin. In addition, a decrease in annual precipitation and changes in temperature in Northern China have also had an adverse effect on natural run‐off, which caused a greater decline in water resources, but this did not have a powerful influence on the overall decline in the run‐off. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
The glacier is an important and stable water supply in Central Asia. Monitoring the change of glacier and understanding the impacts of glacier change on river discharge are critical to predict the downstream water availability change in future. Glacier changes were discussed and their impacts on river discharge were evaluated by hydrological modeling with a distributed hydrological model SWAT under two land use and land cover scenarios (1970 and 2007) in Tekes watershed, the most important source of water discharge to the Ili River. Compared to the glacier area of 1511 km2 in 1970s it decreased by 332 km2 in 2007, which resulted in the contribution the discharge from precipitation in the glacier area to the average annual discharge of the watershed changing from 9.8% in the period 1966–1975 to 7.8% in the period 2000–2008. In the month scale, with the decrease of glacier area, the distribution of the contribution of monthly discharge from precipitation in the glacier area to the total of the watershed changed from bimodal pattern to unimodal pattern. By linking a hydrological model to remote sensing image analysis and Chinese glacier inventories to determine glacier area change our approach in quantifying the impacts of glacier changes on hydrology at different scales, will provide quantitative information for stakeholders in making decisions for water resource management. 相似文献
8.
Hydrological projections of future climate change over the source region of Yellow River and Yangtze River in the Tibetan Plateau: A comprehensive assessment by coupling RegCM4 and VIC model 下载免费PDF全文
下载免费PDF全文 Wenjun Lu Weiguang Wang Quanxi Shao Zhongbo Yu Zhenchun Hao Wanqiu Xing Bin Yong Jinxing Li 《水文研究》2018,32(13):2096-2117
Understanding climate change impacts on hydrological regime and assessing future water supplies are essential to effective water resources management and planning, which is particularly true for the Tibetan Plateau (TP), one of the most vulnerable areas to climate change. In this study, future climate change in the TP was projected for 2041–2060 by a high‐resolution regional climate model, RegCM4, under 3 representative concentration pathways (RCPs): 2.6, 4.5, and 8.5. Response of all key hydrological elements, that is, evapotranspiration, surface run‐off, baseflow, and snowmelt, to future climate in 2 typical catchments, the source regions of Yellow and Yangtze rivers, was further investigated by the variable infiltration capacity microscale hydrological model incorporated with a 2‐layer energy balance snow model and a frozen soil/permafrost algorithm at a 0.25°×0.25° spatial scale. The results reveal that (a) spatial patterns of precipitation and temperature from RegCM4 agree fairly well with the data from China Meteorological Forcing Dataset, indicating that RegCM4 well reproduces historical climatic information and thus is reliable to support future projection; (b) precipitation increase by 0–70% and temperature rise by 1–4 °C would occur in the TP under 3 RCPs. A clear south‐eastern–north‐western spatial increasing gradient in precipitation would be seen. Besides, under RCP8.5, the peak increase in temperature would approach to 4 °C in spring and autumn in the east of the TP; (c) evapotranspiration would increase by 10–60% in 2 source regions due to the temperature rise, surface run‐off and baseflow in higher elevation region would experience larger increase dominantly due to the precipitation increase, and streamflow would display general increases by more than 3% and 5% in the source regions of Yellow and Yangtze rivers, respectively; (d) snowmelt contributes 11.1% and 16.2% to total run‐off in the source regions of Yellow and Yangtze rivers, respectively, during the baseline period. In the source region of Yangtze River, snowmelt run‐off would become more important with increase of 17.5% and 18.3%, respectively, under RCP2.6 and RCP4.5 but decrease of 15.0% under RCP8.5. 相似文献
9.
Streamflow simulation is often challenging in mountainous watersheds because of incomplete hydrological models, irregular topography, immeasurable snowpack or glacier, and low data resolution. In this study, a semi-distributed conceptual hydrological model (SWAT-Soil Water Assessment Tool) coupled with a glacier melting algorithm was applied to investigate the sensitivity of streamflow to climatic and glacial changes in the upstream Heihe River Basin. The glacier mass balance was calculated at daily time-step using a distributed temperature-index melting and accumulation algorithm embedded in the SWAT model. Specifically, the model was calibrated and validated using daily streamflow data measured at Yingluoxia Hydrological Station and decadal ice volume changes derived from survey maps and remote sensing images between 1960 and 2010. This study highlights the effects of glacier melting on streamflow and their future changes in the mountainous watersheds. We simulate the contribution of glacier melting to streamflow change under different scenarios of climate changes in terms of temperature and precipitation dynamics. The rising temperature positively contributed to streamflow due to the increase of snowmelt and glacier melting. The rising precipitation directly contributes to streamflow and it contributed more to streamflow than the rising temperature. The results show that glacial meltwater has contributed about 3.25 billion m3 to streamflow during 1960–2010. However, the depth of runoff within the watershed increased by about 2.3 mm due to the release of water from glacial storage to supply the intensified evapotranspiration and infiltration. The simulation results indicate that the glacier made about 8.9% contribution to streamflow in 2010. The research approach used in this study is feasible to estimate the glacial contribution to streamflow in other similar mountainous watersheds elsewhere. 相似文献
10.
Assessment of transmission loss in a Mediterranean karstic watershed (Wadi Natuf,West Bank) 下载免费PDF全文
下载免费PDF全文 Run‐off transmission loss into karstified consolidated aquifer bedrock below ephemeral streams (wadis) has rarely been described nor quantified. This study presents unique data of long‐term high‐resolution field measurements and field observations in a semiarid to subhumid Mediterranean carbonatic mountainshed. The catchment with a 103 km2 surface area is subdivided into 5 subcatchments. Coupled run‐off measurements were made in the different stream sections (reaches), and transmission loss calculated from differences in discharge. Rainfall and run‐off observations from 9 automated precipitation gauging stations and 5 pressure transducers for automatic water level recording are complemented by manual measurements during 34 run‐off events covering a total measurement period of 8 consecutive years. Run‐off generation is strongly event based depending on rainfall intensities and depths. Both, run‐off generation and transmission losses are related to spatial patterns of bedrock lithologies (and hydrostratigraphy). Transmission losses range between 62% and 80% of generated run‐off, with most of the smaller events showing 100% transmission loss. Therefore, although event run‐off coefficients in the mountains can reach up to 22%, only 0.11% of total annual precipitation leaves the catchment as run‐off. Most run‐off infiltrates directly into the regional karst aquifers (Upper Cretaceous carbonate series), with transmission loss intensities of up to 40 mm/h below the stream channels. The factors determining run‐off—such as geology, pedology, vegetation cover and land use, relief and morphology, the semiarid to subhumid Mediterranean climate with a strong elevation gradient, and the patchiness of individual storm events distributed over the winter seasons—as well as the lithology and epikarst features of the bedrock are all characteristic for larger areas in the Mediterranean region. Therefore, we expect that our findings can be generalized to a large extent. 相似文献
11.
Streamflow generation was investigated using isotopic and geochemical tracers in semiarid, glacier-covered, montane catchments in the upper Shule River, northeastern Tibetan Plateau. Samples from stream water, precipitation, glacier meltwater, and groundwater were collected at the Suli and Gahe catchments along the Shule River, with an area of 1908 and 4210 km2, respectively. The samples were analysed for stable isotopes of water and major ions. Results of diagnostic tools of mixing models showed that Ca2+, Mg2+ and Cl−, along with δ18O and δ2H, behaved conservatively as a result of mixing of three endmembers. The three endmembers identified by the mixing analysis were surface runoff directly from precipitation, groundwater, and glacier meltwater. Streamflow was dominated by groundwater, accounting for 59% and 60% of streamflow on average in the Suli and Gahe catchments, respectively, with minimum groundwater contribution in July (47% and 50%) and maximum contribution in October (69% and 70%). The contributions of surface runoff were slightly higher in the Suli catchment (25%) than in the Gahe catchment (19%). However, the contributions of glacier meltwater were higher in the Gahe catchment (21%) compared to the Suli catchment (17%), as a result of a higher percentage of glacier covered area in the Gahe catchment. This difference followed well the non-linear power–law trend of many glacier-covered catchments around the world. As glacier retreat continues in the future, the reduction of streamflow in glacier-covered upper Shule catchment likely will be accelerated and possibly elsewhere in the Tibetan Plateau. This study suggests that it is critical to define the turning point of an accelerated reduction in glacier meltwater for glacier-covered catchments around the world in order to better assess and manage water resources. 相似文献
12.
《国际泥沙研究》2022,37(2):238-247
The significant reduction of sediment load flux into Lake Baikal from its main tributary – the Selenga River began in the mid-1970s, and can be explained by climate change and socio-economic activities. Integrated analysis was done of changes in hydro-meteorological parameters (water discharge, sediment load, air temperature, and precipitation) and their tendencies over periods of 1946–1975 (baseline) and 1976–2017 (warming). Changes in natural processes and human activity were negligible during the baseline period. In the warming period, against the background of an increase in temperature, the water discharge had a slight decreasing trend (?13%) whereas the sediment load has significantly decreased (?53%) these are consist with the precipitation change (?9.4%). Analysis of hydro-climatic data using statistical methods showed that in the warming period the greatest reduction in river sediment runoff occurred in the interval 1996–2017. In this period the sediment load was 768 × 103 t/yr, which is less than the average value during the warming period – 1048 × 103 t/yr. Considering sedimentation in the Selenga River delta, the actual sediment load flux from the Selenga River into Lake Baikal amounted to 515 × 103 t/yr, which is three times less than the average multiyear value 1535 × 103 t/yr for observation period (1946–2017). 相似文献
13.
The warming of the Earth's atmosphere system is likely to change temperature and precipitation, which may affect the climate, hydrology and water resources at the river basins over the world. The importance of temperature change becomes even greater in snow or glacier dominated basins where it controls the snowmelt processes during the late‐winter, spring and summer months. In this study hydrologic responses of streamflow in the Pyanj and Vaksh River basins to climate change are analysed with a watershed hydrology model, based on the downscaled atmospheric data as input, in order to assess the regional climate change impact for the snowfed and glacierfed river basins in the Republic of Tajikistan. As a result of this analysis, it was found that the annual mean river discharge is increasing in the future at snow and glacier dominated areas due to the air temperature increase and the consequent increase in snow/ice melt rates until about 2060. Then the annual mean flow discharge starts to decrease from about 2080 onward because the small glaciers start to disappear in the glacier areas. It was also found that there is a gradual change in the hydrologic flow regime throughout a year, with the high flows occuring earlier in the hydrologic year, due to the warmer climate in the future. Furthermore, significant increases in annual maximum daily flows, including the 100‐year return period flows, at the Pyanj and Vaksh River basins toward the end of the 21st century can be inferred from flood frequency analysis results. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
14.
Water temperature dynamics in High Arctic river basins 总被引：2，自引：0，他引：2
Despite the high sensitivity of polar regions to climate change and the strong influence of temperature upon ecosystem processes, contemporary understanding of water temperature dynamics in Arctic river systems is limited. This research gap was addressed by exploring high‐resolution water column thermal regimes for glacier‐fed and non‐glacial rivers at eight sites across Svalbard during the 2010 melt season. Mean water column temperatures in glacier‐fed rivers (0.3–3.2 °C) were lowest and least variable near the glacier terminus but increased downstream (0.7–2.3 °C km–1). Non‐glacial rivers, where discharge was sourced primarily from snowmelt runoff, were warmer (mean: 2.9–5.7 °C) and more variable, indicating increased water residence times in shallow alluvial zones and increased potential for atmospheric influence. Mean summer water temperature and the magnitude of daily thermal variation were similar to those of some Alaskan Arctic rivers but low at all sites when compared with alpine glacierized environments at lower latitudes. Thermal regimes were correlated strongly (p < 0.01) with incoming short‐wave radiation, air temperature, and river discharge. Principal drivers of thermal variability were inferred to be (i) water source (i.e. glacier melt, snowmelt, groundwater); (ii) exposure time to the atmosphere; (iii) prevailing meteorological conditions; (iv) river discharge; (v) runoff interaction with permafrost and buried ice; and (vi) basin‐specific geomorphological features (e.g. channel morphology). These results provide insight into the potential changes in high‐latitude river systems in the context of projected warming in polar regions. We hypothesize that warmer and more variable temperature regimes may prevail in the future as the proportion of bulk discharge sourced from glacial meltwater declines and rivers undergo a progressive shift towards snow water and groundwater sources. Importantly, such changes could have implications for aquatic species diversity and abundance and influence rates of ecosystem functioning in high‐latitude river systems. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
Stable isotopic and geochemical identification of groundwater evolution and recharge sources in the arid Shule River Basin of Northwestern China 总被引：5，自引：0，他引：5 下载免费PDF全文
下载免费PDF全文 Xiaoyan Guo Qi Feng Wei Liu Zongxing Li Xiaohu Wen Jianhua Si Haiyang Xi Rui Guo Bing Jia 《水文研究》2015,29(22):4703-4718
Stable isotopic (δDVSMOW and δ18OVSMOW) and geochemical signatures were employed to constrain the geochemical evolution and sources of groundwater recharge in the arid Shule River Basin, Northwestern China, where extensive groundwater extraction occurs for agricultural and domestic supply. Springs in the mountain front of the Qilian Mountains, the Yumen‐Tashi groundwater (YTG), and the Guazhou groundwater (GZG) were Ca‐HCO3, Ca‐Mg‐HCO3‐SO4 and Na‐Mg‐SO4‐Cl type waters, respectively. Total dissolved solids (TDS) and major ion (Mg2+, Na+, Ca2+, K+, SO42?, Cl? and NO3?) concentrations of groundwater gradually increase from the mountain front to the lower reaches of the Guazhou Basin. Geochemical evolution in groundwater was possibly due to a combination of mineral dissolution, mixing processes and evapotranspiration along groundwater flow paths. The isotopic and geochemical variations in melt water, springs, river water, YTG and GZG, together with the end‐member mixing analysis (EMMA) indicate that the springs in the mountain front mainly originate from precipitation, the infiltration of melt water and river in the upper reaches; the lateral groundwater from the mountain front and river water in the middle reaches are probably effective recharge sources for the YTG, while contribution of precipitation to YTG is extremely limited; the GZG is mainly recharged by lateral groundwater flow from the Yumen‐Tashi Basin and irrigation return flow. The general characteristics of groundwater in the Shule River Basin have been initially identified, and the results should facilitate integrated management of groundwater and surface water resources in the study area. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
16.
Huawu Wu Jinglu Wu Kadyrbek Sakiev Jinzhao Liu Jing Li Bin He Ya Liu Beibei Shen 《水文研究》2019,33(12):1658-1669
Characterization of spatial and temporal variability of stable isotopes (δ18O and δ2H) of surface waters is essential to interpret hydrological processes and establish modern isotope–elevation gradients across mountainous terrains. Here, we present stable isotope data for river waters across Kyrgyzstan. River water isotopes exhibit substantial spatial heterogeneity among different watersheds in Kyrgyzstan. Higher river water isotope values were found mainly in the Issyk‐Kul Lake watershed, whereas waters in the Son‐Kul Lake watershed display lower values. Results show a close δ18O–δ2H relation between river water and the local meteoric water line, implying that river water experiences little evaporative enrichment. River water from the high‐elevation regions (e.g., Naryn and Son‐Kul Lake watershed) had the most negative isotope values, implying that river water is dominated by snowmelt. Higher deuterium excess (average d = 13.9‰) in river water probably represents the isotopic signature of combined contributions from direct precipitation and glacier melt in stream discharge across Kyrgyzstan. A significant relationship between river water δ18O and elevation was observed with a vertical lapse rate of 0.13‰/100 m. These findings provide crucial information about hydrological processes across Kyrgyzstan and contribute to a better understanding of the paleoclimate/elevation reconstruction of this region. 相似文献
17.
Potential changes in glacier area, mass balance and runoff in the Yarkant River Basin (YRB) and Beida River Basin (BRB) are projected for the period from 2011 to 2050 employing the modified monthly degree‐day model forced by climate change projection. Future monthly air temperature and precipitation were derived from the simple average of 17, 16 and 17 General Circulation Model (GCM) projections following the A1B, A2 and B1 scenarios, respectively. These data were downscaled to each station employing the Delta method, which computes differences between current and future GCM simulations and adds these changes to observed time series. Model parameters calibrated with observations or results published in the literature between 1961 and 2006 were kept unchanged. Annual glacier runoff in YRB is projected to increase until 2050, and the total runoff over glacier area in 1970 is projected to increase by about 13%–35% during 2011–2050 relative to the average during 1961–2006. Annual glacier runoff and the total runoff over glacier area in 1970 in BRB is projected to increase initially and then to reach a tipping point during 2011–2030. There are prominent increases in summer, but only small increase in May and October of glacier runoff in YRB, and significant increases during late spring and early summer and significant decreases in July and late summer of glacier runoff in BRB. This study highlights the great differences among basins in their response to future climate warming. The specific runoff from areas exposed after glacier retreat relative to 1970 is projected to general increasing, which must be considered when evaluating the potential change of glacier runoff. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
18.
Run‐off processes from mountains to foothills: The role of soil stratigraphy and structure in influencing run‐off characteristics across high to low relief landscapes 下载免费PDF全文
下载免费PDF全文 The critical zone features that control run‐off generation, specifically at the regional watershed scale, are not well understood. Here, we addressed this knowledge gap by quantitatively and conceptually linking regional watershed‐scale run‐off regimes with critical zone structure and climate gradients across two physiographic provinces in the Southeastern United States. We characterized long‐term (~20 years) discharge and precipitation regimes for 73 watersheds with United States Geological Survey in‐stream gaging stations across the Appalachian Mountain and Piedmont physiographic provinces of North Carolina. Watersheds included in this analysis had <10% developed land and ranged in size from 14.1–4,390 km2. Thirty‐four watersheds were located in the Piedmont physiographic province, which is typically classified as a low relief landscape with deep, highly weathered soils and regolith. Thirty‐nine watersheds were located in the Appalachian Mountain physiographic province, which is typically classified as a steeper landscape with highly weathered, but shallower soils and regolith. From the United States Geological Survey daily mean run‐off time series, we calculated annual and seasonal baseflow indices (BFI), minimum, mean, and maximum daily run‐off, and Pearson's correlation coefficients between precipitation and baseflow. Our results showed that Appalachian Mountain watersheds systematically had higher minimum daily flows and BFI values. Piedmont watersheds displayed much larger deviations from mean annual BFI in response to year‐to‐year variability in precipitation. A series of linear regression models between 21 landscape metrics and annual BFIs showed non‐linear and complex terrestrial–hydrological relationships across the two provinces. From these results, we discuss how distinct features of critical zone architecture, with specific focus on soil depth and stratigraphy, may be dominating the regulation of hydrological processes and run‐off regimes across these provinces. 相似文献
19.
Identifying run‐off contributions during melt‐induced run‐off events in a glacierized alpine catchment 下载免费PDF全文
下载免费PDF全文 Michael Engel Daniele Penna Giacomo Bertoldi Andrea Dell'Agnese Chris Soulsby Francesco Comiti 《水文研究》2016,30(3):343-364
We analysed contributions to run‐off using hourly stream water samples from seven individual melt‐induced run‐off events (plus one rainfall event) during 2011, 2012 and 2013 in two nested glacierized catchments in the Eastern Italian Alps. Electrical conductivity and stable isotopes of water were used for mixing analysis and two‐component and three‐component hydrograph separation. High‐elevation snowmelt, glacier melt and autumn groundwater were identified as major end‐members. Discharge and tracers in the stream followed the diurnal variations of air temperature but markedly reacted to rainfall inputs. Hysteresis patterns between discharge and electrical conductivity during the melt‐induced run‐off events revealed contrasting loop directions at the two monitored stream sections. Snowmelt contribution to run‐off was highest in June and July (up to 33%), whereas the maximum contribution of glacier melt was reached in August (up to 65%). The maximum groundwater and rainfall contributions were 62% and 11%, respectively. Run‐off events were generally characterized by decreasing snowmelt and increasing glacier melt fractions from the beginning to the end of the summer 2012, while run‐off events in 2013 showed less variable snowmelt and lower glacier melt contributions than in 2012. The results provided essential insights into the complex dynamics of melt‐induced run‐off events and may be of further use in the context of water resource management in alpine catchments. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
20.
Modeling the runoff and glacier mass balance in a small watershed on the Central Tibetan Plateau,China, from 1955 to 2008 总被引：1，自引：0，他引：1
The glaciers on Tibetan Plateau play an important role in the catchment hydrology of this region. However, our knowledge with respect to water circulation in this remote area is scarce. In this study, the HBV light model, which adopts the degree‐day model for glacial melting, was employed to simulate the total runoff, the glacier runoff and glacier mass balance (GMB) of the Dongkemadi River Basin (DRB) at the headwater of the Yangtze River on the Tibetan Plateau, China. Firstly, the daily temperature and precipitation of the DRB from 1955 to 2008 were obtained by statistical methods, based on daily meteorological data observed in the DRB (2005–2008) and recorded by four national meteorological stations near the DRB (1955–2008). Secondly, we used 4‐year daily air temperature, precipitation, runoff depth and monthly evaporation, which were observed in the DRB, as input to obtain a set of proper parameters. Then, the annual runoff, the glacier runoff and GMB (1955–2008) were calculated using the HBV model driven by interpolated meteorological data. The calculated GMB fits well with the observed results. At last, using the temperature and precipitation predicted by climate models, we predicted the changes of runoff depth and GMB of the DRB in the next 40 years. Under all climate‐change scenarios, annual glacier runoff shows a significant increase due to intensified ice melting. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献