scholarly journals Variation of Runoff and Runoff Components of the Upper Shule River in the Northeastern Qinghai–Tibet Plateau under Climate Change

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3357
Author(s):  
Jinkui Wu ◽  
Hongyuan Li ◽  
Jiaxin Zhou ◽  
Shuya Tai ◽  
Xueliang Wang

Quantifying the impact of climate change on hydrologic features is essential for the scientific planning, management and sustainable use of water resources in Northwest China. Based on hydrometeorological data and glacier inventory data, the Spatial Processes in Hydrology (SPHY) model was used to simulate the changes of hydrologic processes in the Upper Shule River (USR) from 1971 to 2020, and variations of runoff and runoff components were quantitatively analyzed using the simulations and observations. The results showed that the glacier area has decreased by 21.8% with a reduction rate of 2.06 km2/a. Significant increasing trends in rainfall runoff, glacier runoff (GR) and baseflow indicate there has been a consistent increase in total runoff due to increasing rainfall and glacier melting. The baseflow has made the largest contribution to total runoff, followed by GR, rainfall runoff and snow runoff, with mean annual contributions of 38%, 28%, 18% and 16%, respectively. The annual contribution of glacier and snow runoff to the total runoff shows a decreasing trend with decreasing glacier area and increasing temperature. Any increase of total runoff in the future will depend on an increase of rainfall, which will exacerbate the impact of drought and flood disasters.

2015 ◽  
Vol 61 (225) ◽  
pp. 127-136 ◽  
Author(s):  
Meiping Sun ◽  
Zhongqin Li ◽  
Xiaojun Yao ◽  
Mingjun Zhang ◽  
Shuang Jin

AbstractThe impact of climate change on the variability of local discharge was investigated in a glacierized high mountain catchment located in the source area of the Ürümqi river, northwest China. We used past climate records to drive a hydrological model to simulate the discharge from 2000 to 2008. The model was then used to project future discharge variations for the period 2041–60, based on a regionally downscaled climate-change scenario combined with three stages of glacier coverage (i.e. compared to the glacier coverage in 2008): unchanged glacier size (100% glacierized), recession of half the glacier area (50% glacierized) and complete disappearance of glaciers (0% glacierized). In each scenario, snowmelt will begin half a month earlier and the discharge will increase in May. For the 100% glacierized scenario, the discharge will increase by 66 ± 35% in a smaller (3.34 km2) and more glaciated (50%) catchment and 33 ± 20% in a larger (28.90 km2) and proportionally less glaciated (18%) catchment. If the glacier area reduces by half, the discharge will decrease by 8 ± 5% and 9 ± 6%, respectively. Once the glacier disappears, the discharge will decrease by 58 ± 20% and 40 ± 13%, respectively. Together, the results indicate that a warming climate and the resulting glacier shrinkage will cause significant changes in the volume and timing of runoff.


2015 ◽  
Vol 19 (1) ◽  
pp. 379-387 ◽  
Author(s):  
I. Andrés-Doménech ◽  
R. García-Bartual ◽  
A. Montanari ◽  
J. B. Marco

Abstract. Measuring the impact of climate change on flood frequency is a complex and controversial task. Identifying hydrological changes is difficult given the factors, other than climate variability, which lead to significant variations in runoff series. The catchment filtering role is often overlooked and thus may hinder the correct identification of climate variability signatures on hydrological processes. Does climate variability necessarily imply hydrological variability? This research aims to analytically derive the flood frequency distribution based on realistic hypotheses about the rainfall process and the rainfall–runoff transformation. The annual maximum peak flow probability distribution is analytically derived to quantify the filtering effect of the rainfall–runoff process on climate change. A sensitivity analysis is performed according to typical semi-arid Mediterranean climatic and hydrological conditions, assuming a simple but common scheme for the rainfall–runoff transformation in small-size ungauged catchments, i.e. the CN-SCS model. Variability in annual maximum peak flows and its statistical significance are analysed when changes in the climatic input are introduced. Results show that depending on changes in the annual number of rainfall events, the catchment filtering role is particularly significant, especially when the event rainfall volume distribution is not strongly skewed. Results largely depend on the return period: for large return periods, peak flow variability is significantly affected by the climatic input, while for lower return periods, infiltration processes smooth out the impact of climate change.


2019 ◽  
Vol 51 (2) ◽  
pp. 272-289 ◽  
Author(s):  
Yueguan Zhang ◽  
Zhenchun Hao ◽  
Chong-Yu Xu ◽  
Xide Lai

Abstract Located in the Tibetan Plateau, the upstream regions of the Mekong River (UM) and the Salween River (US) are very sensitive to climate change. The ‘VIC-glacier‘ model, which links a degree-day glacier algorithm with variable infiltration capacity (VIC) model, was employed and the model parameters were calibrated on observed streamflow, glacier mass balance and MODIS snowcover data. Results indicate that: (1) glacier-melt runoff exhibits a significant increase in both areas by the Mann–Kendall test. Snowmelt runoff shows an increasing trend in the UM, while the US is characterized by a decreasing tendency. In the UM, the snowmelt runoff peak shifts from June in the baseline period 1964–1990 to May for both the 1990s and 2000s; (2) rainfall runoff was considered as the first dominant factor driving changes of river discharge, which could be responsible for over 84% in total runoff trend over the two regions. The glacial runoff illustrates the secondary influence on the total runoff tendency; (3) although the hydrological regime is rain dominated in these two basins, the glacier compensation effect in these regions is obvious, especially in dry years.


2020 ◽  
Author(s):  
Sarah L. Wakelin ◽  
Yuri Artioli ◽  
Momme Butenschön ◽  
Jason Holt ◽  
Jeremy Blackford

<p>Dissolved oxygen in the ocean is an indicator of water quality and low concentrations can threaten ecosystem health. The main sources of marine oxygen are diffusion from the atmosphere and phytoplankton photosynthesis. Biological respiration and decomposition act to reduce oxygen concentrations. Under conditions of vertical stratification, the water column below the pycnocline is isolated from oxygen exchange with the atmosphere, photosynthesis may be limited by light availability and oxygen concentrations decrease. Climate change influences the oxygen cycle in two ways: 1) changing the hydrodynamic climate and 2) affecting rates of biogeochemical processes. The hydrodynamic climate affects the nutrient supply and so controls phytoplankton production while changes to water column stratification affects vertical mixing. Gas solubility decreases with increasing temperature so that oxygen uptake from the atmosphere is expected to decrease under increasing oceanic temperatures. Biological cycling rates increase with increasing temperature affecting photosynthesis, respiration and bacterial decomposition. It is not obvious whether changes in oxygen concentrations due to changing ecosystem processes will mitigate or reinforce the projected reduction from solubility changes.</p><p>The Northwest European Continental shelf (NWES) is a region of the northeast Atlantic that experiences seasonal stratification. We use the physics-biogeochemical model NEMO-ERSEM to study near-bed oxygen concentrations on the NWES under a high greenhouse gas emissions scenario (Representative Concentration Pathway (RCP) 8.5). We show that much of the NWES could experience low oxygen concentrations by 2100 and assess the relative impacts of changing temperature and ecosystem processes. Until about 2040 the impact of solubility dominates the oxygen change. The mean near-bed oxygen concentration is projected to decrease by 6.3% by 2100, of which 73% is due to solubility changes and the remainder to changes in the ecosystem. In the oxygen-depleted region in the eastern North Sea, 77% of the near-bed oxygen reduction is due to ecosystem processes.</p>


2020 ◽  
Author(s):  
Li Wang ◽  
Fan Zhang

<p>The glacier ratio influences both the contribution of meltwater runoff and the response of the basin's hydrological processes to climate change. In this study, the Karuxung, the Tuotuo and the Babao river basins with glaciers accounting for 20.7%, 2.1% and 0.38% respectively, were selected to study their hydrological processes under the climate change. Based on the daily runoff data of 30 years and MODIS snow cover products, the J2000 model was applied to quantify the contribution of meltwater and rainfall runoff, analyze the temporal and spatial variation characteristics of runoff and clarify the influence of climate change on these three basin. The main findings are as follows: (1) The contribution of glacier and snow melt runoff for the Karuxung, Tuotuo and Babao river basin was 60.7%, 25.3% and 19.9%, respectively. The contribution of rainfall runoff for the three basins was 39.3%, 74.7% and 81.1%, respectively. (2) The peak of glacier and snow melt runoff converted from summer to spring with the glacier ratio decreasing. (3) The runoff supplies in the Karuxung, Tuotuo and Babao river basin were from the 5500m-6500m, 4500m-5500m zone, and 3500m-4500m elevation zone, respectively. (4) The runoff and its components in the Karuxung and Tuotuo river basins showed significant increasing trends while the Babao river basin showed no significant change trends. (5) In the Karuxung river basin with large glacier ratio, the increase in temperature mainly caused the increase of meltwater and runoff, showing a positive impact on runoff. For the Tuotuo and Babao river basin with small glacier ratios, the increase in temperature mainly caused increased evaporation and reduced runoff, showing a negative impact on runoff.</p>


2014 ◽  
Vol 9 (4) ◽  
pp. 432-442 ◽  
Author(s):  
Nobuhiko Sawai ◽  
◽  
Kenichiro Kobayashi ◽  
Apip ◽  
Kaoru Takara ◽  
...  

This paper assesses the impact of climate change in the Black Volta River by using data output from the atmospheric general circulation model with a 20-km resolution (AGCM20) through the Japanese Meteorological Agency (JMA) and the Meteorological Research Institute (MRI). The Black Volta, which flows mainly in Burkina Faso and Ghana in West Africa, is a major tributary of the Volta River. The basin covers 142,056 km2 and has a semi-arid tropical climate. Before applying AGCM20 output to a rainfall–runoff model, the performance of the AGCM20 rainfall data is investigated by comparing it with the observed rainfall in the Black Volta Basin. To assess the possible impact of rainfall change on river flow, a kinematic wave model, which takes into consideration saturated and unsaturated subsurface soil zones, was performed. The rainfall analysis shows that, the correlation coefficient of the monthly rainfall between the observed rainfall and AGCM20 for the present climate (1979–2004) is 0.977. In addition, the analysis shows that AGCM20 overestimates precipitation during the rainy season and underestimates the dry season for the present climate. The analysis of the AGCM20 output shows the precipitation pattern change in the future (2075–2099). In the future, precipitation is expected to increase by 3%, whereas evaporation and transpiration are expected to increase by 5% and by 8%, respectively. Also, daily maximum rainfall is expected to be 20 mm, or 60%, higher. Thus, the future climate in this region is expected to be more severe. The rainfall–runoff simulation is successfully calibrated at the Bamboi discharge gauging station in the Black Volta fromJune 2000 to December 2000 with 0.72 of the Nash–Sutcliffe model efficiency index. The model is applied with AGCM20 outputs for the present climate (1979–2004) and future climate (2075–2099). The results indicate that future discharge will decrease from January to July at the rate of the maximum of 50% and increase fromAugust to December at the rate of the maximumof 20% in the future. Therefore, comprehensive planning for both floods and droughts are urgently needed in this region.


2018 ◽  
Author(s):  
Valerie Allain ◽  
Neville Smith ◽  
John Hampton ◽  
Peter Williams ◽  
Graham Pilling ◽  
...  

Long-term collection of data and samples appears critical to contribute to our understanding of the impacts of fisheries and climate change on the marine ecosystems, and for the implementation of management measures for sustainable use of the resources. In the western and central Pacific Ocean, the source of 50% of the worldwide tuna catches, several tools have been implemented to monitor the fisheries and the tuna pelagic ecosystem. Since the 1990’s fisheries observers of 15 Pacific Island countries, which are now operating under a regional standardised framework, collect data on fishing effort, catch and bycatch to monitor, among others, changes in biodiversity. This network of 800 observers also collect biological samples (stomachs, muscles, otoliths…) that constitute a biological tissue bank of pelagic fish with more than 95000 samples available to scientists for biological studies. Since the 1970’s tuna tagging programmes have been implemented to monitor the fishing pressure and tuna movements and growth. Fishing-independent data have also been collected during scientific cruises to monitor the lower levels of the trophic web. These multiple initiatives at the scale of half of the Pacific represent a unique opportunity to understand the impact of fisheries and climate change on the tuna ecosystem.


2020 ◽  
pp. 78-110
Author(s):  
Yu. Rud ◽  
◽  
O. Zaloilo ◽  
L. Buchatsky ◽  
I. Hrytsyniak ◽  
...  

Purpose. As the climate change impacts freshwater and marine ecosystems, and rising ocean temperatures and acidification continue to this moment, our aim was to analyze the literature and summarize information on the development of fish infectious diseases in the light of global warming. Findings. Even a slight increase in temperature affects the life cycle, physiology, behavior, distribution and structure of populations of aquatic bioresources, especially fish. Recent studies show that some infectious diseases of fish spread much faster with increasing temperature. Climate change contributes to pathogens spread in both marine and freshwater areas. In particular, rising water temperatures can expand the range of diseases. Aquatic bioresources have high cumulative mortality from infectious diseases, and pathogens are rapidly progressing, and these phenomena may be powered by climate change, leading to the geographical spread of virulent pathogens to fisheries and aquaculture facilities, threatening much of global production and food security. The article presents data on the impact of climate change and global warming on aquaculture and fisheries. The list of the main pathogens of fish of various etiology in Ukraine, including viral, bacterial and parasitic diseases is presented. The impact of infectious agents on modern aquaculture is described and the main ideas about the possible long-term consequences of climate change for fish farms are given. Practical Value. The review may be useful for specialists in veterinary medicine, epizootology and ichthyopathology. Key words: climate change, infectious diseases of fish, pathogenesis.


2018 ◽  
Author(s):  
Valerie Allain ◽  
Neville Smith ◽  
John Hampton ◽  
Peter Williams ◽  
Graham Pilling ◽  
...  

Long-term collection of data and samples appears critical to contribute to our understanding of the impacts of fisheries and climate change on the marine ecosystems, and for the implementation of management measures for sustainable use of the resources. In the western and central Pacific Ocean, the source of 50% of the worldwide tuna catches, several tools have been implemented to monitor the fisheries and the tuna pelagic ecosystem. Since the 1990’s fisheries observers of 15 Pacific Island countries, which are now operating under a regional standardised framework, collect data on fishing effort, catch and bycatch to monitor, among others, changes in biodiversity. This network of 800 observers also collect biological samples (stomachs, muscles, otoliths…) that constitute a biological tissue bank of pelagic fish with more than 95000 samples available to scientists for biological studies. Since the 1970’s tuna tagging programmes have been implemented to monitor the fishing pressure and tuna movements and growth. Fishing-independent data have also been collected during scientific cruises to monitor the lower levels of the trophic web. These multiple initiatives at the scale of half of the Pacific represent a unique opportunity to understand the impact of fisheries and climate change on the tuna ecosystem.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yanfei Li ◽  
Zhaohua Li ◽  
Zhihui Li ◽  
Xiaoli Geng ◽  
Xiangzheng Deng

The climatic effects of LUCC have been a focus of current researches on global climate change. The objective of this study is to investigate climatic effects of grassland degradation in Northwest China. Based on the stimulation of the conversion from grassland to other land use types during the next 30 years, the potential effects of grassland degradation on regional climate in the overgrazing area of Northwest China from 2010 to 2040 have been explored with Weather Research and Forecasting model (WRF). The analysis results show that grassland will mainly convert into barren land, croplands, and urban land, which accounts for 42%, 48%, and 10% of the total converted grassland area, respectively. The simulation results indicate that the WRF model is appropriate for the simulation of the impact of grassland degradation on climate change. The grassland degradation during the next 30 years will result in the decrease of latent heat flux, which will further lead to the increase of temperature in summer, with an increment of 0.4–1.2°C, and the decrease of temperature in winter, with a decrement of 0.2°C. In addition, grassland degradation will cause the decrease of precipitation in both summer and winter, with a decrement of 4–20 mm.


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