Attribution analysis of the spatiotemporal variation in water balance in a typical semiarid basin in northern China

Abstract

Climate change and anthropogenic factors have significantly impacted hydrological regimes, especially in semiarid regions. Using the trend-free pre-whitening Mann-Kendall (TFPW-MK) test and linear regression, trends of precipitation, temperature, runoff, and water balances from different spatiotemporal scales were analysed during the past sixty years in the Upper Yongding River Basin (UYRB). Based on the Choudhury-Yang equation, the contributions of climate change and human activities to runoff variation were further quantified in five mountainous catchments, and the actual effects of climate change and human activities on the water balance in the whole UYRB were also discussed. The results suggest that the UYRB has become much warmer and drier. The lower annual precipitation and intensity in summer were directly attributed to runoff reductions. Intra-annual scale analyses of meteorological, hydrological and biological responses helped the comprehensive interpretation of the runoff trends. Human activities, including agricultural irrigation, were the main causes for runoff reduction, especially in the middle and lower reaches, and the contribution of human activities increased gradually in recent decades. The water balance changed drastically temporally, with the precipitation being converted less to runoff and more to evaporated fractions, which was also due to the second order effects of climate change and vegetation improvement. It is suggested that low water-consumption plant species and the related water-saving techniques in agriculture and afforestation should be introduced for the sustainable development in the similar regions.

Variation of the Omo Delta between 1990 and 2018: What remote sensing data reveal and models explain

“…Secondly, to disentangle the influences of climatic and anthropogenic factors on deltaic changes, we draw upon methods employed in studies focusing on surface water dynamics with similar objectives. Studies have used physically based hydrological models (e.g., Soil and Water Assessment Tool and Variable Infiltration Capacity) (Ahmed et al, 2022; Zhang et al, 2015), conceptual hydrologic models (e.g., Tomer Schilling framework) (Tomer & Schilling, 2009), climate elasticity‐based models (e.g., non‐parametric and parametric Budyko frameworks) (Lee & Yeh, 2019; Xu et al, 2014) and statistical approaches such as regression models, double mass curves and time‐series analysis (Gaines et al, 2022; Lu et al, 2022). Given the limitations, requirements of each method and the characteristics of our catchment, we opted for the statistical approach utilizing parametric and non‐parametric regression models.…”

Changes in climate, vegetation cover and vegetation composition affect runoff generation in the Gulf of Guinea Basin

“…However, climate change and variability characterized by the intensification of the global hydrological cycle and changes in rainfall patterns may alter the partitioning of precipitation into runoff and actual evapotranspiration (ET) with subsequent effects on water availability at different scales (Allan et al, 2020; Yang et al, 2021; Zheng et al, 2019). Vegetation cover change and other anthropogenic activities also exert substantial impact on the partitioning of precipitation into runoff and ET (Lu et al, 2022; Luo et al, 2020; Wang & Stephenson, 2018). As such, a better understanding of the different climatic and environmental factors influencing runoff generation may be critical for sustainable water management and adaptation planning.…”

“…Several studies have investigated the impact of climate variability and vegetation change on runoff (Luo et al, 2020; Wang & Stephenson, 2018). However, most existing studies focused on the impact of vegetation cover change (Gbohoui et al, 2021; Lu et al, 2022), whereas the impact of changes in vegetation composition (i.e., the proportion of different vegetation types) on runoff have received less attention. Vegetation composition is measured using vegetation continuous fields (VCFs) and include tree canopy cover (TC), short vegetation cover (SV) and bare ground cover (BG).…”

Trend Projections of Potential Evapotranspiration in Yangtze River Delta and the Uncertainty

“…[1]. The actual evapotranspiration is often invisible and difficult to monitor [2]. Therefore, it is usually estimated from potential evapotranspiration (ETp) through methods based on hydrology, micrometeorology, etc.…”

“…is located in the east coast of China, covering a land area of 359 thousand km 2 . There are three provinces (Anhui, Jiangsu, Zhejiang) and a municipality (Shanghai) directly under the central government in this delta, formulating one of the ten largest city clusters in the world.…”