Water Tower Research Articles

Impacts of Bias‐Corrected ERA5 Initial Snow Depth on Dynamical Downscaling Simulations for the Tibetan Plateau

AbstractThe Tibetan Plateau (TP) is often called the “Water Tower of Asia,” which contains the largest amount of snow and glaciers outside the polar regions. As an important and variable feature of the land surface, snow coverage on the TP has great impacts on regional climate. However, the commonly used ERA5 reanalysis in dynamical downscaling largely overestimates the snow depth for the TP. To improve the representation of snow cover in ERA5, a new ERA5‐driven downscaling data set (High Asia Refined analysis version 2, HAR v2) was generated by the Weather Research and Forecasting (WRF) model with the bias‐corrected snow depth. This study aims to identify and better understand the impact of bias‐corrected initial snow conditions on simulated regional climate, by comparing the HAR v2 with a 5‐year ERA5 forced WRF simulation without bias correction of initial snow depth (referred to as WRF_ERA5). The results show that the bias correction significantly improves the simulation of 2 m air temperature (T2), with regional mean cold bias reduced by 0.2°C–2.4°C, but no significant improvement in precipitation simulation is found. Further comparative analysis reveals that higher snow depth in WRF_ERA5 leads to T2, mean daily precipitation, summer extreme precipitation, and contributions of convective precipitation to summer mean daily precipitation decrease by 0°C–4°C, 0%–60%, 0%–40%, and 0%–10%, respectively, in most areas of the TP. In addition, the bias‐corrected initial snow depth also has impacts on simulated diurnal cycles of precipitation and T2 and leads to peak hours one hour earlier. Overall, this study confirms the importance of snow cover for the climate in the TP.

A high-accuracy rainfall dataset by merging multiple satellites and dense gauges over the southern Tibetan Plateau for 2014–2019 warm seasons

Abstract. Tibetan Plateau (TP) is well known as Asia's water tower from where many large rivers originate. However, due to complex spatial variability in climate and topography, there is still a lack of a high-quality rainfall dataset for hydrological modeling and flood prediction. This study therefore aims to establish a high-accuracy daily rainfall product through merging rainfall estimates from three satellites, i.e., GPM-IMERG, GSMaP and CMORPH, based on a high-density rainfall gauge network. The new merged daily rainfall dataset with a spatial resolution of 0.1∘ focuses on warm seasons (10 June–31 October) from 2014 to 2019. Statistical evaluation indicated that the new dataset outperforms the raw satellite estimates, especially in terms of rainfall accumulation and the detection of ground-based rainfall events. Hydrological evaluation in the Yarlung Zangbo River basin demonstrated high performance of the merged rainfall dataset in providing accurate and robust forcings for streamflow simulations. The new rainfall dataset additionally shows superiority to several other products of similar types, including MSWEP and CHIRPS. This new rainfall dataset is publicly accessible at https://doi.org/10.11888/Hydro.tpdc.271303 (Li and Tian, 2021).

Evapotranspiration and energy partitioning of a typical alpine wetland in the central Tibetan Plateau

The alpine wetlands in the Tibetan Plateau (TP) account for more than 30% of the wetlands in China. As an ecosystem that is particularly sensitive to the changing climate, the rapid warming of the TP may have a significant impact on the growth of vegetation in these cold wetlands. However, due to the lack of ground observations, it remains unclear how the land-atmosphere exchanges of water and energy develop in such special alpine ecosystems. This limits the understanding of how eco-hydrological processes respond to environmental changes. In this study, we used ground measured data to investigate the dynamics of energy partitioning and water budget over a typical wetland in the central TP over two hydrological years. The results demonstrate that the seasonal variations in land-atmosphere energy exchange were significant during the observation period. In the growing season, the available energy was mainly consumed by latent heat flux (LE), with the mean ratio of LE to net radiation (Rn) exhibiting values of 0.68 and 0.76 in 2019 and 2020, respectively. During the freezing period, the available energy was primarily consumed by sensible heat flux (H), with mean ratio of H to Rn values of 0.69 and 0.68 in 2019 and 2020, respectively. The total annual evapotranspiration (ET) (include sublimation) in 2019 and 2020 were 652.5 mm and 706.6 mm, respectively. Annual ET was found to be higher than precipitation (P), indicating that soil water was supplied via lateral flow from the melting of upstream glaciers and snow, supporting ET from the wetland. During the growing season, ET was mainly controlled by solar radiation but became more strongly coupled with soil water during the freezing period. Evaluations of four typical gridded ET products suggest that the Penman–Monteith–Leuning (PML) model showed the best performance with the highest Nash-Sutcliffe Efficiency (NSE) when compared with the ground-measured ET rates, indicating that this product may be appropriate for use in similar data-scarce regions. The land-atmosphere energy and water exchanges in the alpine wetland are important for an improved understanding of the hydrological cycle of the Asian Water Tower and could be used as a reference for further ET model parameterizations and validations.

Process, mechanisms, and early warning of glacier collapse-induced river blocking disasters in the Yarlung Tsangpo Grand Canyon, southeastern Tibetan Plateau

Glacier collapse is a fairly new type of glacier-related disasters on the Asian Water Towers (AWTs) in the warming climate. On 16 October and 29 October 2018, two glacier collapses occurred in the Sedongpu Basin, 7 km downstream from Gyala Village, Paizhen Town, Miling County, on the Yarlung Tsangpo River (YTR). The ice and entrained debris flows caused by the glacier collapses blocked the YTR, resulting in a potential threat to residents and transport lines upstream and downstream. Through post-event field investigations with a helicopter and an unmanned aerial vehicle (UAV), remote sensing interpretation, and seismic, hydrological, and meteorological observations, the process and potential mechanisms of the glacier collapse-induced river blocking (GCRB) disasters were investigated. We confirmed that the first glacier collapse event occurred at 22:48 (Beijing time) on 16 October 2018 and the second began at 08:03 on 29 October 2018. Approximately 130 × 106 m3 of ice and debris detached from the glacier during the glacier collapse, and we calculated that the river blocking fans caused by the first and second glacier collapse event covered ~1.36 km2 and ~ 1.29 km2 on the main watercourse of the YTR, respectively. We determined that the GCRB incidents represent a disaster chain of glacier collapse → glacial debris flow → river blockage → dammed lake → outburst flood. These incidents arise due to a combination of factors, including glacier activity, climate warming, heavy precipitation, pre-seismic activity, and high topographic relief. In the context of climate warming on the Tibetan Plateau, such glacier collapse induced disaster chains will continue or even intensify in the future. To protect against glacier collapse disasters in the Grand Canyon on the YTR, we established a monitoring and early warning system (EWS), which has already successfully sounded alerts for GCRB incidents. As a major element of an integrated risk management strategy, the EWS represents a viable and promising tool for mitigating climate change-related risks.

Assessment of water pollution in the Tibetan Plateau with contributions from agricultural and economic sectors: a case study of Lhasa River Basin.

The freshwater environment of watersheds in the Tibetan Plateau is bound with the safety of the Asian Water Tower. In this study, nitrogen (N) and phosphorus (P) loads delivered to freshwater and the associated gray water footprint (GWF) in the agriculture, tourism, domestic life, and industrial sectors were estimated to assess the seasonal and annual characteristics of the water pollution levels (WPLs) in the Lhasa River Basin from 2006 to 2018, and WPL calculations were compared with actual water quality measurements from 2017 to 2018. We found that more than 90% of the GWF came from anthropogenic sources. From the perspective of the whole basin, domestic life was the largest contributor to both N-related GWFs (52%) and P-related GWFs (50%), followed by agriculture for N-related GWFs (32%) and tourism industry for P-related GWFs (30%). The N emissions into the freshwater environment exceeded the maximum assimilation capacity of the watersheds in individual years at both seasonal and annual scales, while P emissions were completely within the pollution assimilative capacity. Besides, we found the serious N pollution near irrigation areas at the seasonal scale (WPL = 2.7 and TN = 1.11 mg/L). The prosperity of tourism has led to a tenfold increase in N-related GWFs and a fivefold increase in P-related GWFs for the tourism industry near the Lhasa city. The strict top-down unified management for ecological environmental protection in plateaus may be an effective method.

Land use and climate change effects on water yield from East African forested water towers

Abstract. East African forested mountain regions are vital in generating and supplying water resources to adjacent arid and semi-arid lowlands. However, these ecosystems are under pressure from both climate and land use changes. This study aimed to analyze the effects of climate and land use changes on water yield using the Budyko framework as a first-order conceptual framework assuming steady-state for pristine/protected forested areas. For nine selected forested water towers in East Africa, the amount and distribution of water resources and their decadal changes were analyzed. Results show that most areas inside and outside the water towers are under pressure from human influences. Water yield was more sensitive to climate changes compared to land use changes within the selected East African water towers themselves. However, for the surrounding lowlands, the effects of land use changes had greater impacts on water yield. We conclude that the East African water towers have seen a strong shift towards wetter conditions, especially in the period of 2011–2019, while, at the same time, the potential evapotranspiration is gradually increasing. Given that most of the water towers were identified as non-resilient to these changes, future water yield is likely to also experience more extreme variations.

Enhanced aridity in the source region of the Yangtze River since 5.8 ka revealed by the sediments of Saiyong Co

The Yangtze River is a major component of the ‘Asian Water Tower’ and it provides freshwater resources for hundreds of millions of people in East Asia. Hence, climatic and environmental changes in the source region of the Yangtze River (SRYR) are of major significance for understanding changes in the status of its freshwater resources. However, due to the contradictory results shown by the available paleoclimatic records from the SRYR and neighboring regions, it remains unclear how the regional climate and hydrology have evolved since the middle Holocene. Here, we present records of hydrological variations based on multiple proxies (grain size, scanned micro-scale X-ray fluorescence (XRF) element composition, and loss on ignition (LOI)) of the sediments of alpine lake Saiyong Co, with the aim of reconstructing hydrological changes in the SRYR since 5.8 ka. The first principal component (PC1) of the XRF scanned element record is dominated by Ti, Fe and K, representing terrigenous inputs from the catchment. The LOI profile shows an inverse pattern of variation to that of PC1, suggesting that the sedimentary organic matter is primarily derived from aquatic plants. Since 5.8 ka the overall decrease in sample scores on PC1 and the increasing LOI, together with the grain-size based lake-level record, indicate an overall drying trend in SRYR. Furthermore, several major droughts are recorded, at ∼4.0 ka, ∼2.8 ka and ∼1.8 ka. The hydrological variations at Saiyong Co are supported by multiple records from the SRYR, suggesting that millennial-scale environmental variations were regionally synchronous and were influenced by Northern Hemisphere summer insolation and movement of the intertropical convergence zone.

Improvement of boundary effect model in multi-scale hybrid fibers reinforced cementitious composite and prediction of its structural failure behavior

The inclusion of multi-scale hybrid fibers in cement-based materials exhibits excellent crack resistance performance at multi-level than that of single type or size of fiber. Multi-scale hybrid fiber reinforced cementitious composites (MHFRCCs) can be served as a building material with stringent crack resistance requirements for civil structure such as pipeline, river levee, nuclear reactor, water tower , and sewage treatment sedimentation tank. The tensile strength ( f t ) and fracture toughness ( K IC ) are two important size independent material parameters for guiding structural safety design and stability assessment. In this study, the real f t and K IC of MHFRCCs were determined by three-point bending test based on the boundary effect model. The average aggregate particle size with a large proportion was chosen as the “representative aggregate ( d 1 = 0.45 mm)" by using grading curve. The fiber long axis dimensions that appear most frequently on the cross section were selected as the “representative fiber ( d 2 = 0.28 mm for steel fiber and d 3 = 0.0794 mm for polyvinyl alcohol fiber)" according to the statistical analysis of backscattered electron imaging. The fracture failure behaviors of MHFRCC structure were predicted based on the determined f t and K IC values, and the structural fracture failure bands with ±15% variations were established. In addition, the microstructure analysis of MHFRCC revealed multi-scale enhancement mechanism in the cement matrix . Finally, the complete fracture process images and P-CMOD curve were divided into three stages: pre-cracking stage, crack stable propagation stage, and unstable failure stage. This analysis would be helpful to understand the fracture crack resistance effect of multi-scale hybrid fibers at multi-level within cement matrix. • Backscattered electron imaging was used to determine hybrid fiber morphologies based on statistical analysis. • The relationship between fictitious crack growth and the fibers-aggregates system was established. • Size independent fracture parameters of MHFRCC were determined using boundary effect model. • Structural failure curves/bands were constructed to predict the fracture behavior of MHFRCC. • Microscopic analysis and complete fracture process images confirmed the multi-scale crack resistance mechanism for MHFRCC.

Community Behavior Patterns That Influence The Causes of Dengue Hemorrhagic Fever (DHF) in The Pondok Petir Elementary Region

Dengue Hemorrhagic Fever (DHF) is a disease caused by the bite of the Aedes Aegypti mosquito infected with one of the four types of dengue virus with clinical manifestations of fever, muscle aches, and/or joint pain accompanied by leukopenia, rash, lymphadenopathy, thrombocytopenia and hemorrhagic diathesis. In dengue hemorrhagic fever, plasma leakage occurs which is characterized by hemoconcentration (increased hematocrit) or fluid accumulation in body cavities (World Health Organization). Dengue Hemorrhagic Fever Penyakit (DHF) is still one of the main public health problems in Indonesia. The number of sufferers and the area of ​​spread of DHF is increasing along with the increase in mobility and population density, especially in tropical and sub-tropical areas (Kemenkes RI, 2010). At the beginning of 2019, Dengue Hemorrhagic Fever (DHF) again increased in several areas, even becoming an Extraordinary Event (KLB) status. In January 2019 there were 15,132 DHF sufferers with 145 people dying in 34 provinces. This figure is twice as high as the figure at the end of January 2018 which recorded 6,167 DHF sufferers with 43 people dying. To find out the behavioral factors of DHF disease in the community in the Pondok Petir sub-district area in 2020. Research Setting: According to data in 2019, Dengue Hemorrhagic Fever (DHF) has increased again in several areas, even becoming an Extraordinary Event (KLB) status. In January 2019 there were 15,132 DHF sufferers with 145 people dying in 34 provinces. This figure is twice as high as the figure at the end of January 2018 which recorded 6,167 DHF sufferers with 43 people dying. East Java, West Java, and DKI Jakarta are the three provinces that experienced an increase in the number of dengue cases compared to the previous year. This research uses the Simple Random Sampling technique. This study studied the incidence of dengue in children to adults (dependent variable), with respondent characteristics (age, history of dengue disease), counseling (knowledge), attitudes (family attitudes), and behavioral patterns (behavior of health workers, rarely monitoring larvae). mosquitoes, distribution of abate powder, fogging activities), and increasing community participation in dengue prevention (independent variable). To obtain the data, an in-depth interview and document review approach was conducted with the community at Pondok Petir. This research was conducted at Pondok Petir, South Tangerang in June 2021. The sub-categories in this study were DHF, Age, History of DHF, Knowledge, Family Attitude, Behavioral Patterns, Behavioral Patterns of Health Workers, Rarely Monitoring Mosquito Larvae, Distribution of Abate Powder, Fogging Activities, Facilities, Facilities, Increased Participation Society in Dengue Prevention. It takes a lot of education to the people of Pondok Petir to make people aware of the importance of knowing about DHF. The most effective and efficient prevention of dengue fever to date is the Mosquito Nest Eradication (PSN) activity using 3M Plus, namely: 1) Draining, is cleaning places that are often used as water reservoirs such as bathtubs, water buckets, water reservoirs drinking water, water reservoirs, refrigerators, etc. 2) Closing, namely closing water reservoirs such as drums, jugs, water towers, and so on; and 3) Reusing or recycling used goods that have the potential to become breeding grounds for dengue-transmitting mosquitoes.

Effects of ZnO/water nanofluid on the thermal performance of wet cooling towers

This article deals with an experimental investigation on the thermal performance of a mechanical draft wet cooling tower when using Zinc Oxide (ZnO) nanoparticles and three packing types with different densities. Stable nanofluids with different weight concentrations of ZnO/water were prepared through a two-step procedure using distilled water. First of all, the influence of three packing types including 7,9 and 18 layers are investigated on the thermal performance of the wet cooling tower using ZnO/water nanofluid with a weight concentration of 0.1%. Secondly, five ZnO/water nanofluids with weight concentrations of 0.02, 0.04, 0.06, 0.08, and 0.1% are utilized to examine the effects of nanoparticle concentration on the performance. The results indicate that water temperature difference, cooling efficiency, and tower characteristic could enhance by increasing layers of packing and weight concentrations of nanofluid. Moreover, the nanofluid effects are more notable when the denser packing is used.

Experimental determining of horizontal movements of the water tower reservoirs by GB-RAR

Ground-based radar interferometry (GBRI) with ground-based real aperture radar (GB-RAR) is most often used for monitoring vertical deflections of bridge structures caused by vehicle passages. This paper presents an experimental determining of the horizontal dynamic movements of water tower reservoirs by GB-RAR. Determining the dynamic movements of water tower reservoirs is more complicated precisely because the movement of the reservoir is influenced not only by external influences, such as wind, but also by the movement of water mass in the reservoir. The resulting oscillation is then a composite oscillation of multiple frequencies. Next, in the case of routine determination of vertical deflections of bridge structures, it is reasonable to assume a predominant deflection of the structure in this one particular direction. But in the case of tower structures such as reservoirs, it is necessary to assume their movements (oscillations) in the entire horizontal plane. The movements can be circular, elliptical, straight, spiral, or even completely irregular. This means using at least two radars to simultaneously determine 2D movements (in both perpendicular directions of the horizontal plane). In the optimal case, the radars aim at the monitored object in approximately perpendicular directions to each other, and the resulting motion vectors in the horizontal plane are calculated from LOS measurements. The processing of measurements from both radars raises other problems, namely accurate time synchronization of radar measurements. In case of tower structures, time synchronization cannot be solved by coincidence of oscillation amplitude peaks, since the peaks from different radar views may not occur simultaneously. Therefore, alternative solution is offered in this contribution. Purpose of this contribution is to design and verify a procedure for accurate determination of horizontal movements of tower reservoirs with sufficiently accurate oscillation characteristics. The procedure was experimentally verified in practice on a real water reservoir in central Bohemia. The results of the experiment confirm the expected benefits of simultaneous measurements by two radars for determining horizontal dynamic movements of water tower reservoirs by GB-RAR.

Divergent trends of water bodies and their driving factors in a high-latitude water tower, Changbai Mountain

The importance of natural water towers to water resource demand of the ecological environment and human activities is self-evident. They are also vulnerable and extremely sensitive to the effects of anthropogenic activities and climate change. However, water bodies change in water towers have not received sufficient attention. Therefore, Changbai Mountain, a typical high-latitude water tower, which is the source of Second Songhua River, Tumen River, and Yalu River, was selected to analyze the change of water bodies and its response to interaction of driving factors over recent decades by the methods of Correlation analysis and Geodetector. Results showed that there was an obviously divergent trend in water bodies, with a significant increase in surface water area (SWA) and a significant decrease in terrestrial water storage (TWS) in the high-latitude water tower, which was firstly found. The strong increase in water use was the dominant factor causing the divergent trends of water bodies in Tumen River. Changes in water bodies in the other two basins were all the result of the combined effects of climate change and anthropogenic activities. It is worth mentioning that snowpack had a noticeable influence on the change of water storage in this water tower. Meanwhile, reduced water conservation capacity due to degradation of complex forest-wetland ecosystems and altered snowmelt processes in the context of climate warming may be two key underlying causes. In addition, we innovatively found that the enhanced interactivity of the driving factors was an inherent reason. The results of this study will be beneficial for ecosystem conservation and stability of downstream water supply in this high-latitude water tower.

A first investigation of hydrogeology and hydrogeophysics of the Maqu catchment in the Yellow River source region

Abstract. The Tibetan Plateau is the source of most of Asia's major rivers and has been called the Asian Water Tower. Detailed knowledge of its hydrogeology is paramount to enable the understanding of groundwater dynamics, which plays a vital role in headwater areas like the Tibetan Plateau. Nevertheless, due to its remoteness and the harsh environment, there is a lack of field survey data to investigate its hydrogeology. In this study, borehole core lithology analysis, soil thickness measurement, an altitude survey, hydrogeological surveys, and hydrogeophysical surveys (e.g. magnetic resonance sounding – MRS, electrical resistivity tomography – ERT, and transient electromagnetic – TEM) were conducted in the Maqu catchment within the Yellow River source region (YRSR). The hydrogeological surveys reveal that groundwater flows from the west to the east, recharging the Yellow River. The hydraulic conductivity ranges from 0.2 to 12.4 m d−1. The MRS sounding results, i.e. water content and hydraulic conductivity, confirmed the presence of an unconfined aquifer in the flat eastern area. Based on TEM results, the depth of the Yellow River deposits was derived at several places in the flat eastern area, ranging from 50 to 208 m. The soil thickness measurements were done in the western mountainous area of the catchment, where hydrogeophysical and hydrogeological surveys were difficult to be carried out. The results indicate that most soil thicknesses, except on the valley floor, are within 1.2 m in the western mountainous area of the catchment, and the soil thickness decreases as the slope increases. These survey data and results can contribute to integrated hydrological modelling and water cycle analysis to improve a full-picture understanding of the water cycle at the Maqu catchment in the YRSR. The raw dataset is freely available at https://doi.org/10.17026/dans-z6t-zpn7 (Li et al., 2020a), and the dataset containing the processed ERT, MRS, and TEM data is also available at the National Tibetan Plateau Data Center with the link https://doi.org/10.11888/Hydro.tpdc.271221 (Li et al., 2020b).

The Grand Ethiopian Renaissance Dam: Africa's Water Tower, Environmental Justice & Infrastructural Power

Abstract Global environmental imaginaries such as “the climate crisis” and “water wars” dominate the discussion on African states and their predicament in the face of global warming and unmet demands for sustainable livelihoods. I argue that the intersecting challenges of water, energy, and food insecurity are providing impetus for the articulation of ambitious state-building projects, in the Nile Basin as elsewhere, that rework regional political geographies and expand “infrastructural power”–the ways in which the state can penetrate society, control its territory, and implement consequential policies. The Grand Ethiopian Renaissance Dam should be understood as intending to alter how the state operates, domestically and internationally; how it is seen by its citizens; and how they relate to each other and to their regional neighbors. To legitimize such material and ideational transformations and reposition itself in international politics, the Ethiopian party-state has embedded the dam in a discourse of “environmental justice”: a rectification of historical and geographical ills to which Ethiopia and its impoverished masses were subjected. However, critics have adopted their own environmental justice narratives to denounce the failure of Ethiopia's developmental model and its benefiting of specific ethnolinguistic constituencies at the expense of the broader population.

Seismic vulnerability assessment of free-standing massive masonry columns by the 3D Discrete Element Method

Free-standing masonry column is a recurrent typology of built cultural heritage. Usually raised without seismic design, columns are subject to intense rocking and overturning under strong ground motions. In this paper, a strategy to assess their seismic vulnerability using the 3-D Discrete Element Method is proposed. It includes calibrating the elastic parameters (joint stiffness parameters) using ambient vibration test data and developing fragility curves from a large set of time history analysis results. This procedure was verified for four selected water towers, a representative archaeological monument in Pompeii, Italy. Based on preliminary structural analyses, the water towers were modeled as rigid monolithic blocks. The outcomes of modal analysis were used to calibrate the input elastic parameters, starting from a range of values given by analytical calculations derived by literature. Artificial earthquakes with peak ground acceleration levels ranging from 0.167 g to 0.803 g were implemented as ground motions. Collapses and non-collapses configurations were subdivided through a threshold concerning the maximum allowable rotation of the blocks. Fragility curves were statistically developed; these revealed the overturning probabilities of the investigated structures and also enabled to conduct a parametric study of the Rayleigh damping constants.

Climate and Landscape Controls on the Water Balance in Temperate Forest Ecosystems: Testing Large Scale Controls on Undisturbed Catchments in the Central Appalachian Mountains of the US

AbstractThe long‐term water balance of catchments is given by precipitation partitioned into either runoff or evaporation. Understanding precipitation partitioning controls is a critical focus of hydrology and water resources management. A useful theoretical framework that serves their understanding is the Budyko Framework. Our purpose is to understand how Budyko's n parameter is related to different controls and what is its relevance to precipitation partitioning. We investigated the relative importance of the dryness index and the Budyko parameter for precipitation partitioning, then applied partial correlation analysis and multivariate regressions to find out which were the principal partitioning controls. We focused our research in the central Appalachian mountains located in the eastern United States, considered as water towers to metropolitan areas in the eastern and mid‐western US (e.g., Pittsburgh, Washington DC), and selected a set of catchments characterized by minimal human disturbance and with large proportions of temperate forests. We found that climate controls such as mean annual temperature and fraction of precipitation falling in the form of snow exert a higher influence on partitioning than landscape controls (e.g., forest cover, Normalized Difference Vegetation Index, and slope). Thus, the importance of vegetation as a primary driver of partitioning could not be confirmed based on regional or basin‐wide characteristics. On the other hand, the influence of topography, and elevation in particular, was highly ranked as important. Our study highlights that partitioning controls could differ between basins in the same climate region, especially in a complex, mountainous topography setting.

Resilient Predictive Control Coupled with a Worst-Case Scenario Approach for a Distributed-Generation-Rich Power Distribution Grid

In a context of accelerating deployment of distributed generation in power distribution grid, this work proposes an answer to an important and urgent need for better management tools in order to ‘intelligently’ operate these grids and maintain quality of service. To this aim, a model-based predictive control (MPC) strategy is proposed, allowing efficient re-routing of power flows using flexible assets, while respecting operational constraints as well as the voltage constraints prescribed by ENEDIS, the French distribution grid operator. The flexible assets used in the case study—a low-voltage power distribution grid in southern France—are a biogas plant and a water tower. Non-parametric machine-learning-based models, i.e., Gaussian process regression (GPR) models, are developed for intraday forecasting of global horizontal irradiance (GHI), grid load, and water demand, to better anticipate emerging constraints. The forecasts’ quality decreases as the forecast horizon grows longer, but quickly stabilizes around a constant error value. Then, the impact of forecasting errors on the performance of the control strategy is evaluated, revealing a resilient behaviour where little degradation is observed in terms of performance and computation cost. To enhance the strategy’s resilience and minimise voltage overflow, a worst-case scenario approach is proposed for the next time step and its contribution is examined. This is the main contribution of the paper. The purpose of the min–max problem added upstream of the main optimisation problem is to both anticipate and minimise the voltage overshooting resulting from forecasting errors. In this min–max problem, the feasible space defined by the confidence intervals of the forecasts is searched, in order to determine the worst-case scenario in terms of constraint violation, over the next time step. Then, such information is incorporated into the decision-making process of the main optimisation problem. Results show that these incidents are indeed reduced thanks to the min–max problem, both in terms of frequency of their occurrence and the total surface area of overshooting.

Future changes in snowpack will impact seasonal runoff and low flows in Czechia

Study RegionCentral Europe, Czechia. Study FocusMountains are referred to as “water towers” because they substantially affect the hydrology of downstream areas. However, snow storages will decrease in the future due to the increase in air temperature which will affect streamflow regime. Main objectives of this study were 1) to simulate the future changes in snow for a large set of mountain catchments in Czechia, reflecting a wide range of climate projections and 2) to analyse how the snow changes will affect groundwater recharge, streamflow seasonality and low flows in the future. New Hydrological InsightsThe future hydrological projections showed a decrease in annual maximum SWE by 30 %–70 % in the study area until the end of the 21st century. Additionally, snowmelt was found to occur on average 3–4 weeks earlier. The results showed the large variability between individual climate chains and indicated that the increase in air temperature causing the decrease in snowfall might be partly compensated by the increase in winter precipitation. Changes in snowpack will cause the highest streamflow during melting season to occur one month earlier, in addition to lower spring runoff volumes due to lower snowmelt inputs. The future climate projections leading to overall dry conditions in summer are associated with both the lowest summer precipitation and seasonal snowpack. The expected lower snow storages might therefore contribute to more extreme low flow periods.

Long-term price guidance mechanism of flexible energy service providers based on stochastic differential methods

With the increasing generation of renewable energy in power markets, the mismatch between power production and power demand in the power market is becoming more serious. Power prices in the short term guided the balance of load and demand. Although short-term power price guidance can provide certain benefits, short-term power price guidance disrupts the potential long-term market balance and provides sustainable development challenges. This paper adopts a stochastic differential method to guide flexible energy service providers for long-term price guidance with addressing the challenges of long-term market imbalances. After knowing power production, the stochastic differentiation method guides load power demand to follow changes in power production by a reasonable power price. The stochastic differential method utilizes energy flexibility for long-term price guidance with cost minimization in a long-term market environment. The power demand results of Zhaoqing considering the water tower model show that the long-term price guidance mechanism based on the stochastic differential method saves 12.39% of the operating cost with RMB 782.6987 million each year. The long-term price guidance based on the stochastic differential method mobilizes the energy flexibility by indirectly control the demand of flexible energy systems through reasonable price signals.

Von den bedrohlichen zu den bedrohten Alpen – Aneignungsprozesse und Identifikationsfiguren alpiner Umweltschützer*innen in Tirol

While in the early days of the European history of culture the Alps were seen as forbidding, since the 1970s environmental activists have used this description, turning it the other way round — now it is the Alps that are increasingly threatened by today’s environmental problems. Noise, air pollution, deforestation and problems relating to ozone depletion threaten the ecologically sensitive Alpine range. The problems affect not just the Alps, but owing to geographical and topographic conditions their consequences are particularly strong here. Thus the Alps constitute a reference framework as well as a point of origin for the thematisation of ecological problems. Defenders of the Alps were especially critical of the claims — or, more openly, designs — of the European Union in the area of transport, tourism and energy. The relations between the Alps and the European Union constituted a unique moment in the discussion of environmental activists. On the one hand they styled the Alps as a model ecological region in contrast to the economy-focused European Union, and on the other the European Union served as a common enemy, which turned the Alps into a political argument in declaring unity of this space. This unity was, according to the defenders of the Alps, important in the context of securing and forcing through the region’s internal needs. To sum up, the Alps were presented as a place where various, partly opposing, economic, ecological and political interest met, and a place appropriated, depending on the context, as a living, cultural and economic space, as Europe’s roof and water tower, or as a holiday idyll and sports arena. Given the collaboration of Alpine environmentalists crossing state borders south and north of the Brenner Pass, and within the extraordinarily politically and socially heterogenous resistance movement in North Tirol, a question arises: to what extent have the Alps generated unique forms of identification for these figures? The author of the article argues that for Alpine environmentalists the Alps are both a discursive and a physical space, used as an identity-building element and space of activity.