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The source region of Yellow river is an alpine river sensitive to climate changes, but the potential effects of climate change on hydrological regime characteristics and ecological implications are less understood. This study aims to assess the response of the alterations in the flow regimes over the source region of Yellow river to climate change using Soil and Water Integrated Model driven by different Global Circulation Models (GFDL-ESM2M, IPSL-CM5A-LR and MIROC-ESM-CHEM) under three Representative Concentration Pathway emission scenarios (RCP2.6, RCP4.5 and RCP8.5). Indicators of hydrological alteration and River impact index are employed to evaluate streamflow regime alterations at multiple temporal scales. Results show that the magnitude of monthly and annual streamflow except May, the magnitude and duration of the annual extreme, and the number of reversals are projected to increase in the near future period (2020-2049) and far future period (2070-2099) compared to the baseline period (1971-2000). The timing of annual maximum flows is expected to shift backwards. The source region of Yellow river is expected to undergo low change degree as per the scenarios RCP2.6 for both two future periods and under the scenarios RCP4.5 for the near future period, whereas high change degree under RCP4.5 and RCP8.5 in the far period on the daily scale. On the monthly scale, climate changes mainly have effects on river flow magnitude and timing. The basin would suffer an incipient impact alteration in the far period under RCP4.5 and RCP8.5, while low impact in other scenarios. These changes in flow regimes could have several positive impacts on aquatic ecosystems in the near period but more detrimental effects in the far period. [ABSTRACT FROM AUTHOR]

Abstract: Length‐weight relationships (LWRs) were estimated for four fish species [Schizopygopsis anteroventris Wu & Tsao, 1989, Schizothorax lissolabiatus Tsao, 1964, Triplophysa markehenensis (Zhu & Wu, 1981) and Triplophysa siluroides (Herzenstein, 1888)] from the Yellow River. Samples were collected seasonally from August 2016 to October 2017, using various fishing gears [set nets (mesh: 1.5 cm × 2.0 cm), hook, drift gill nets (mesh: 1.0 cm × 2.0 cm × 3.0 cm) and electro fishing]. Four new maximum standard length were recorded for S. anteroventris, S. lissolabiatus, T. markehenensis and T. siluroides. [ABSTRACT FROM AUTHOR]

Reliable projections of extremes at finer spatial scales are important in assessing the potential impacts of climate change on societal and natural systems, particularly for elevated and cold regions in the Tibetan Plateau. This paper presents future projections of extremes of daily precipitation and temperature, under different future scenarios in the headwater catchment of Yellow River basin over the 21st century, using the statistical downscaling model (SDSM). The results indicate that: (1) although the mean temperature was simulated perfectly, followed by monthly pan evaporation, the skill scores in simulating extreme indices of precipitation are inadequate; (2) The inter-annual variabilities for most extreme indices were underestimated, although the model could reproduce the extreme temperatures well. In fact, the simulation of extreme indices for precipitation and evaporation were not satisfactory in many cases. (3) In future period from 2011 to 2100, increases in the temperature and evaporation indices are projected under a range of climate scenarios, although decreasing mean and maximum precipitation are found in summer during 2020s. The findings of this work will contribute toward a better understanding of future climate changes for this unique region. [ABSTRACT FROM AUTHOR]

We established a Juniperus przewalski tree ring width chronology, based on tree ring cores collected from the A'nyêmaqên Mountains. Statistical analysis showed that the chronology was highly correlated with instrumental streamflow records from previous August to current July from the Tangnaihai Station in the upper reaches of the Yellow River, with a correlation coefficient of 0.656. Streamflow for the upper reaches of the Yellow River was reconstructed for the past 1234 years. Low flow periods for the 11-year averaged streamflow reconstruction were definite as lower than mean plus 1 standard deviation, and high flow periods were higher than mean minus 1 standard deviation. Over the past 1234 years, high flows occurred 18 times, and low flows occurred 12 times. The main low flow periods were identified as AD 1140-1156, AD 1295-1309, AD 1473-1500, and AD 1820-1847, and the main high flow periods were identified as AD 846-873, and AD 1375-1400. Extremely low streamflow over the reconstruction period was seen during the late 15th century, coinciding with a widespread drought phenomenon, which took place in the northeastern Tibetan Plateau over the same period. Reconstructed streamflow shows significant low-frequency variability, which is in line with drought variability of neighboring regions, as inferred from tree rings and other proxies. Multi-taper spectral analysis suggests the existence of significant periods of 2-5, 22, 35-38, 55-62, and 114-227 years, particularly significant for cyclic variations of years 159 and 36. [ABSTRACT FROM AUTHOR]

Low-flow is widely regarded as the primary flow conditions for the anthropogenic and aquatic communities in most rivers, particularly in such an arid and semi-arid area as the Yellow River. This study presents a method integrating Mann–Kendall trend test, wavelet transform analysis and spatial mapping techniques to identify the temporal and spatial patterns of low-flow changes in the Yellow River (1955–2005). The results indicate that: (1) no trend can be identified in the major low-flow conditions in the upper Yellow River, but downward trends can be found in the middle and lower Yellow River; (2) similar periodic patterns are detected in the 7-day minima (AM7Q) in the upper and middle Yellow River, while different patterns are found in the lower Yellow River; (3) the increasing coefficients of variance in the primary low-flow conditions suggest that the variability of the low-flow is increasing from the upper to lower stream; (4) climate change and uneven temporal-spatial patterns of precipitation, jointly with highly intensified water resource utilization, are recognized as the major factors that led to the decrease of low-flow in the lower Yellow River in recent decades. The current investigation should be helpful for regional water resources management in the Yellow River basin, which is characterized by serious water shortage. [ABSTRACT FROM AUTHOR]

Snow has been widely recognized as a crucial component of water resources and is expected to be vulnerable to climate change in cold and mountainous regions. Here we projected climate change impacts on snow hydrology in the upper Yellow River (UYR) basin through a distributed biosphere hydrological model with improved snow physics, forced with Inter‐Sectoral Impact Model Intercomparison Project climate model outputs under two emission scenarios (representative concentration pathways, RCP4.5 and RCP8.5) during the period of 1996–2025. The results indicated that the climate in the UYR basin is turning warmer and wetter. In this context, more precipitation would occur as rain (snow‐to‐precipitation ratio would decrease accordingly). The total runoff generation would increase slightly with increased precipitation. The simulated snow depth and snow water equivalent would decrease by 33% and 19% per 1 °C warming under the RCP4.5. These declined rates would further enlarge under the RCP8.5. Accordingly, the multimodel ensemble mean snowmelt‐to‐runoff ratio decreases by 9% and 7% per 1 °C warming under the two emission scenarios. The projected responses of snow hydrology (e.g., snow depth, snow water equivalent, and snowmelt) to the changing climate in the UYR basin are consistent among different climate models and RCP scenarios, which would provide valuable insights for water resources management, environmental protection, and climate change adaption in high mountainous basins and their downstream regions. Key Points: Snow hydrological responses to climate change were projected in the UYR basin through a climate‐land surface hydrologic modeling frameworkSnow depth and SWE in the UYR basin would decline with regional climate warming and wettingBiased ISI‐MIP‐GCMs‐outputted air temperature leads to impractical simulation of changes in snow seasonality [ABSTRACT FROM AUTHOR]