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The topography plays an essential role in the initiation and development of precipitating clouds, therefore has a profound effect on the ultimate spatial distribution of precipitation. This study investigates the fine‐scale characteristics of a synoptic‐induced precipitation event in Southwest China, a region characterized by a sequence of steep mountains aligned roughly north‐south. The convection‐permitting simulation successfully reproduces the observed rainband induced by a synoptic‐scale shear line. The spatial distribution of accumulated precipitation over three small‐scale mountains (named M1, M2, and M3 from east to west) exhibits distinct inhomogeneity. The accumulated precipitation is significantly enhanced on the western slope of M1, the high‐altitude area of M2, and the eastern slope of M3. The low‐level vortex generated on the western slope of M1, as well as the convergence established over M2 and the eastern slope of M3, dynamically contributes to the enhanced precipitation over the various mountain locations. As the highest of the three mountains, M2 exhibits pronounced blocking effects on the mesoscale circulations. Additional sensitivity experiment demonstrates that the mesoscale circulations and corresponding precipitation are sensitive to the highest elevation in the continuous mountains. The rainfall accumulation over M2 (M3) could decrease (increase) by 54.3% (63.4%), when the terrain of M2 is reduced to the comparable height of surrounding mountains. With more upslope wind flowing over M2, the convergence over M3 is strengthened. The more intense upward motion and stronger potential instability both contribute to the notable increase of precipitation over M3. This study implies the possible mechanisms of the inhomogeneous precipitation over Southwest China and could deepen the current understanding of the topographic effects on precipitation over complex terrains. Plain Language Summary: Southwest China is characterized by high average elevation with a succession of quasi‐north‐south‐oriented mountains. Such topography with local variance tends to generate inhomogeneous distribution of precipitation. In this study, we explore the spatial characteristics of a typical synoptic‐induced rainfall case that occurs in Southwest China and examine the role of steep topography relief in this rainfall process by using a convection‐permitting model. The simulation reasonably reproduces the distribution and evolution features of the observed rainband. We find significant enhancement of precipitation in the different locations of the small‐scale mountains. The steep topographic relief modulates the distribution of precipitation by exerting dominant influences on local circulations. The results from the sensitivity experiment, in which the terrain of Cang Mountain reduced to the comparable height as the surrounding mountains, further reveal that the highest mountain peaks in this complex terrain region plays a key role in the near‐surface flow patterns and thermal conditions. Consequently, this leads to variations in the enhancement of precipitation over the mountains. Key Points: The precipitation under strong synoptic forcing is significantly enhanced by the steep topography relief of Southwest ChinaThe mesoscale circulations modulated by the steep mountains play an essential role in shaping the distribution of precipitationThe mesoscale circulations and corresponding precipitation are sensitive to the highest elevation in the continuous mountain ranges [ABSTRACT FROM AUTHOR]

Understanding the energy development ideas of the Yellow River Basin has a very important impact on the high-quality development of the Yellow River Basin. Aiming at the restriction and promotion of energy consumption in the Yellow River Basin to its high-quality development, this article takes the nine provinces of the Yellow River as the research object, builds an evaluation model based on the data of the river basin from 2004 to 2017, and uses the entropy method and elastic coefficient method to study the coupling characteristics of watershed energy consumption for its high-quality development in time and space. The results show that the high-quality development level of the river basin is generally increasing, the consumption level is generally decreasing, and the coupling of energy consumption and high-quality development is optimized year by year. Finally, according to the coupling of energy consumption level and high-quality development level, a development strategy suitable for improvement is proposed.

The Yellow River Basin is a major economic development area in China, and the high quality development of the basin still has great room for improvement. The coordinated development of energy, environment, economy and ecology is one of the keys to high quality development of the watershed. Aiming at the problem of energy, environment, economy and ecology restricting and promoting, this paper takes the nine provinces of the Yellow River as the research object, based on data from 2004 to 2017, through establishing the coupling coordination system of ecology, environment, economy and energy, using CRITIC method to study the characteristics of each subsystem of the basin in time and space. The results show that the score of energy, environment, economy and ecology is phased in time, and the level of compound coupling coordination is increasing year by year and the growth rate is obvious. The coupling coordination degree of the Yellow River basin has significant stage and regional characteristics in time and space, the coordination degree of the upper and middle reaches is higher than the coordination degree of the downstream coupling, but the difference between the three is gradually reduced with time.

Using an iterative rain‐cell tracking method to identify and track mesoscale convective system (MCS) precipitation during the warm seasons (May–October) of 2015–2020, we reveal the seasonal variation in the spatiotemporal distribution, rainfall characteristics, and the life cycle of MCS precipitation in different months over North China. Notable MCS precipitation centers are located around mountain slopes and downstream areas. The diurnal peak of MCS rainfall is manifested as a southeastern delay from afternoon in mountainous regions to midnight or morning over downstream plains. In May and June, MCS rainfall is distributed on the hillside of Taihang–Yan mountains and the Shandong Peninsula. MCS precipitation gets an early evening peak on mountain slopes and a nocturnal maximum over the North China Plain (NCP). In July and August, the MCS activities extend to NCP, and another MCS precipitation center exists over the Luliang Mountains in western North China, under the seasonal march of the monsoon flow. The local diurnal peaks to the east of 114°E are generally later than in May and June, and MCS precipitation gets a peak during midnight to early morning over the NCP. MCSs in July and August feature the strongest intensity. In September and October, the MCS precipitation shifts to high terrain of the Taihang Mountains and its west, with an early afternoon peak. MCSs have the largest size and the fastest propagation speed in September and October, but with the weakest intensity. Compared with short‐lived MCSs, long‐lived MCSs have stronger precipitation intensity, larger rainfall area, and faster propagation speed. In addition, the life cycle of long‐lived MCS precipitation represents asymmetric development and decay. Long‐lived MCSs occur with more pronounced upper troposphere warming and low‐level anomalous southwesterlies. Meanwhile, higher specific humidity in the low‐ and mid‐level troposphere provides a more favorable environment for the maintenance of MCS precipitation. [ABSTRACT FROM AUTHOR]

Centrifugal impeller is usually designed for water pumping. Fluid get energy from impeller but also lose energy when passing through it. To improve the efficiency and have a better operation stability, it is necessary to understand the flow energy dissipation in centrifugal impeller in pump mode. In this case, a thermodynamic analysis is conducted on a model centrifugal pump unit based on computational fluid dynamics (CFD) simulation. Typical performance curve is found with a positive-slope efficiency curve and a negative-slope head curve. With the decreasing of flow rate, both the impeller head and the flow energy dissipation (FED) will rise up. The FED is found related to the flow regime. The complex undesirable flow pattern induces high FED under off-design conditions especially at very small partial-load. Based on the visualization, FED is found with two main sources including the wall friction and the flow interaction. At over-load and design-load, the wall friction induced FED is dominant. With the decreasing of flow rate, flow interaction induced FED becomes dominant. The typical strong FED sites are found related to the striking, separation, merging and interaction of both smooth flow and vortical flow. The FED analysis will correlate the pump performance estimation and guide the design. [ABSTRACT FROM AUTHOR]