To facilitate water management and efficient utilization of water resources, the allocation of water rights to individual industries must be underpinned by a rational and defensible process. This study aimed to develop an improved fuzzy analytic hierarchy process method of allocating water rights to different industries and focused on Qing’an County, northeast China as a case study. An evaluation index system for allocation of initial water rights was established, and incorporated physiographic, societal, economic, and ecological criteria. The system classifies four categories of second-level indices, 14 third-level indices, and 30 fourth-level indices. The order of priority of the evaluation index was determined and the total weight of initial water rights for different industries was calculated using the fuzzy analytic hierarchy process method. Results showed that the indices for the allocation of initial water rights ranked in descending order of their total weights coefficient were: (1) agricultural water rights: 0.9508; (2) residential water rights: 0.0240; (3) water rights for non-agricultural production: 0.0173; (4) environmental water rights: 0.0078. Agricultural water consumption accounted for the largest proportion of total water because the study area is a major grain production area. The study provides a theoretical basis for the allocation of water rights and water rights trading in northeast China.
Through a self-designed experimental device according to hydrodynamic conditions of backwater area of branch of Three Gorges Reservoir,the experiment was carried out to study the effects of reynolds number and turbulent flow on the vertical distributions of algae and its suspension and gathered behavior in different water depths.In the condition that water temperature is 20℃,illumination is 5000lx and there are enough nutrient concentrations in water,the experiment results showed that Cyanophyta cells are mainly in the depth ranging from 0.2m to 0.8m when average flow velocity is within 0-0.005m/s and reynolds number is within 0-1750 while Bacillariophyta cells are mainly in the depth ranging from 0.2m to 0.8m when average flow velocity is within 0.1-0.5m/s and reynolds number is within 35000-175000.Compared to Cyanophyta and Bacillariophyta,a considerable part of Chlorophyta cells could suspend in the depth ranging from 0.2m to 0.8m when flow velocity is within 0-0.05m/s and reynolds number is within 0-17500.
It is of great significance to study the characteristics and change trends of drought in Xinjiang to provide a basis for implementing local strategies. Based on monthly precipitation and temperature data from 95 meteorological stations in Xinjiang, from 1960 to 2018, the Standardized Precipitation Evapotranspiration Index (SPEI) was calculated, and the characteristics and trends of drought in Xinjiang were analysed, in details. Furthermore, a comprehensive evaluation index, i.e., Regional Drought Severity (RDS), was proposed to analyse the effects of duration of the drought and the extent of the drought affected area. The results from our study suggested: (1) In consideration of global warming, droughts in Xinjiang have intensified during the past 59 years, and the frequency and range of droughts have increased significantly; (2) During the plant growing season, spring, summer, and autumn, a drying trend was observed, while, a wetting trend was identified for winter season; (3) The drought-prone months shifted from January and December to March-November in the 1970s, and April was identified as a month with the highest frequency of droughts; (4) The meteorological change occurred a period near 1997. It can be speculated that the intensified droughts can be triggered by the excessive temperature rise, through comparing the changes in SPEI and the Standardized Precipitation Index (SPI), before and after the meteorological change; (5) After the meteorological change, the frequency of droughts with different levels had significantly increased, in addition, the drought-prone areas shifted from the north-west to the south-east. The results from this research provide important support for drought management in Xinjiang, also offer scientific basis for the formulation of relevant policies on agricultural and animal husbandry production.
运用GIS技术,在充分考虑气温、湿度、风速以及日照等条件下,计算了1995年1月至2010年12月三峡库区22个气象站点的温湿指数和风效指数及其时空分布,对三峡库区人居环境气候适宜性的总体分布趋势进行分析.并以2003年6月三峡工程一期蓄水作为时间中点,分析了三峡工程蓄水前后库区人居环境气候适宜性变化,同时对库区水位与气象要素的相关性进行定量分析.结果表明:从11月到翌年3月,库区气候偏冷,属于较不舒适人居环境;夏季的6-9月,整个库区气候偏热,属于较不舒适的人居环境;库区年均温湿指数和风效指数均呈现明显的地区差异,整体表现为由库区中部向东西递减的趋势;库区气候适宜性指数在三峡工程前后变化明显,库区水位与气候适宜性因子在2003年6月以前没有显著的相关性,在2003年6月以后,与温湿指数呈显著正相关,而与风效指数呈显著负相关.;Considering the conditions of temperature, humidity, wind speed and sunshine duration, the temporal and spatial distribution of temperature-humidity index(THI) and wind effect index(K) were calculated at 22 weather stations in the Three Gorges Reservoir catchment from January, 1995 to December, 2010 based on GIS technology. The general distribution trend on climate suitability for human settlement in Three Gorges Reservoir was analyzed. The change in climate suitability for human settlement was analyzed before and after impoundment based on the first storage stage of the Three Gorges Project in June, 2003. Correlation analysis of water level and meteorological elements were also investigated. Results show that the climate is not comfortable from November to March in the next year due to the cold temperature. Similarly, the climate is also not comfortable from June to September due to the hot weather. The average annual THI and K exhibit obvious regional difference. The integrative trend of THI and K decreases progressively from central to east and west areas. Climate suitability has changed obviously since the accomplishment of the Three Gorges Project. The results of Pearson's correlation coefficients showed no correlation between THI, K and water level before June 2006, whereas water level showed significantly positive correlation with THI and negative correlation with K after that time.
Under the influence of climate change, the hydrological processes of glaciers have undergone significant changes, a fact which is seriously affecting agricultural production in the downstream region of the Tianshan Mountains, China. In order to explore the intrinsic relationship between climate change and hydrological elements, we proposed an “evaluation-driving-prediction” system to study it. First, we constructed a glacier-enhanced soil and water assessment tool model (GE-SWAT) and used a two-stage calibration method to optimize the model parameters. Next, a scenario analysis was used to evaluate the driving factors of historical runoff changes. Finally, we projected future runoff changes using bias-corrected regional climate model (RCM) outputs. The results of the case study on the Jinghe River Basin in the Tianshan Mountains show that from 1963 to 2016, total runoff increased by 13.3%, 17.7% of which was due to increasing precipitation and 1.8% of which was negated by rising temperatures. The glacier runoff increased by 14.5%, mainly due to the rising temperatures. A 3.4% reduction in snowmelt was caused by a lower snowfall/precipitation ratio, which significantly reduced the snowfall from June to August. The RCM projection indicated that the warming and humidification phenomenon in the study area will continue at least through to the mid-21st century. A consistent increase in glacier runoff and total runoff is projected, but the contribution rate of the glacier runoff will have little to no change under the RCP4.5 and RCP8.5 emission scenarios. Our research demonstrates the simulation performance of the GE-SWAT model in a basin with moderate glacier cover. This method is shown to be efficient in quantifying the impact of climate change on glacier hydrological processes and predicting future streamflow changes, providing a good research reference for similar regions.
The gross primary productivity (GPP) of vegetation stores atmospheric carbon dioxide as organic compounds through photosynthesis. Its spatial heterogeneity is primarily influenced by the carbon uptake period (CUP) and maximum photosynthetic productivity (GPPmax). Grassland, cropland, and forest are crucial components of China’s terrestrial ecosystems and are strongly influenced by the seasonal climate. However, it remains unclear whether the evolutionary characteristics of GPP are attributable to physiology or phenology. In this study, terrestrial ecosystem models and remote sensing observations of multi-source GPP data were utilized to quantitatively analyze the spatio-temporal dynamics from 1982 to 2018. We found that GPP exhibited a significant upward trend in most areas of China’s terrestrial ecosystems over the past four decades. Over 60% of Chinese grassland and over 50% of its cropland and forest exhibited a positive growth trend. The average annual GPP growth rates were 0.23 to 3.16 g C m−2 year−1 for grassland, 0.40 to 7.32 g C m−2 year−1 for cropland, and 0.67 to 7.81 g C m−2 year−1 for forest. GPPmax also indicated that the overall growth rate was above 1 g C m−2 year−1 in most regions of China. The spatial trend pattern of GPPmax closely mirrored that of GPP, although local vegetation dynamics remain uncertain. The partial correlation analysis results indicated that GPPmax controlled the interannual GPP changes in most of the terrestrial ecosystems in China. This is particularly evident in grassland, where more than 99% of the interannual variation in GPP is controlled by GPPmax. In the context of rapid global change, our study provides an accurate assessment of the long-term dynamics of GPP and the factors that regulate interannual variability across China’s terrestrial ecosystems. This is helpful for estimating and predicting the carbon budget of China’s terrestrial ecosystems.
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