Changes In Water Resources Research Articles

Hotspots of Global Water Resource Changes and Their Causes

AbstractIn recent decades, terrestrial water storage anomaly (TWSA) has experienced systematic shifts. Despite these observations, debates continue regarding the hotspots where terrestrial water storage changes dramatically and their causes. This study aims to address these controversies. Utilizing four TWSA products, this research analyzes TWSA's changing patterns and identifies hotspots of significant shifts from 1982 to 2019. The study employed the Bayesian Three‐Cornered Hat method to synthesize the best‐quality TWSA from original four TWSA products and the trends consistent method to identify regions with highly consistent trends. Subsequently, the elasticity coefficient method was used to reveal the causes of TWSA's dramatic changes in hotspots. Results show that TWSA has a declining trend over 66.1% global terrestrial areas during 1982–2019, with an average rate of −0.5 mm/y. The study identified six regions where marked changes in TWSA occurred, including Northern China, Southern Canada, Northern India, Central‐Southern Europe, Southwestern Africa, and Northeastern South America. Attribution analysis reveals that the leaf area index is the predominant factor affecting TWSA changes, dominating in 40.3% of global regions. Potential evapotranspiration (PET) follows closely, dominating in 39.8% of global regions. Meanwhile, only 13.1% and 6.8% of global regions are primarily influenced by precipitation and cropland density respectively. The dominant factor varies in different latitudes. Vegetation greening primarily controls TWSA changes in the high‐latitude regions of the Northern Hemisphere. This study identified hotspots of TWSA changes and investigated the causes of these variations. Those results will offer direction for prioritizing areas in future water resource management.

Monitoring Environmental Degradation and Spatial Changes in Vegetation and Water Resources in the Brazilian Pantanal

Diagnosing climate variability and environmental change in floodable regions is essential for understanding and mitigating impacts on natural ecosystems. Our objective was to characterize environmental degradation in the Brazilian Pantanal by identifying changes in vegetation and water cover over a 30-year period using remote sensing techniques. We evaluated surface physical–hydric parameters, including Land Use and Land Cover (LULC) maps, Normalized Difference Vegetation Index (NDVI), Modified Normalized Difference Water Index (MNDWI), Normalized Difference Moisture Index (NDMI), and precipitation data. There was a decrease in the area of water bodies (−9.9%), wetlands (−5.7%), and forest formation (−3.0%), accompanied by an increase in the area of pastureland (7.4%). The NDVI showed significant changes in vegetation cover (−069 to 0.81), while the MNDWI showed a decrease in water surface areas (−0.73 to 0.93) and the NDMI showed a continuous decrease in vegetation moisture (−0.53 to 1). Precipitation also decreased over the years, reaching a minimum of 595 mm. Vegetation indices and land use maps revealed significant changes in vegetation and loss of water bodies in the Pantanal, reinforcing the need for sustainable management, recovery of degraded areas, and promotion of ecotourism to balance environmental conservation and local development.

Applying Budyko framework to explore the projected hydrologic changes in southern Taiwan

This study combines future rainfall and temperature projections with the Budyko framework to analyze future water resource changes in four key watersheds in southern Taiwan under climate change scenarios. Since only temperature and rainfall data are available in the future climate change projections, the future evapotranspiration projections are estimated by this study. This study establishes Budyko equations of each watershed, using historical evapotranspiration and temperature data along with potential evapotranspiration estimates, to project future evapotranspiration based on future temperature and rainfall data. The future rainfall is expected to gradually increase, with the most significant increase under the SSP5-8.5 scenario. However, the rainfall increase varies with the geographical location (latitude) of the watershed, with higher rainfall increases in northern watersheds, such as Zengwen, Jiaxian, and Nanhua. Moreover, the projected evapotranspiration differs in watersheds in southern Taiwan indicating the uncertainty and challenge of evapotranspiration projection under climate change. The future runoff projections indicate an increasing trend with a significant increase (13.4–20.3%) by the end of the century (2081–2100), due to projected increases in rainfall and minor changes in evapotranspiration. The projected increase in runoff implies an optimistic outlook in water resources planning and management, but may pose a threat in flood disasters due to increased rainfall in the wet season.

Changes in vegetation ecosystem carbon sinks and their response to drought in the karst concentration distribution area of Asia

Changes in net ecosystem productivity (NEP) in karst areas can have a significant impact on terrestrial ecosystem carbon cycling, yet quantifying changes in vegetation NEP and its response to factors such as drought and hydroclimate remains a difficult challenge because of its special climatic and hydrological conditions. We used remote sensing data to estimate vegetation NEP in the Asian karst concentrated distribution area (AKC), analyzed its spatial and temporal variations annually (2000−2020) and during rainy season (May–November), established the drought fluorescence monitoring index (DFMI), and used a ridge regression model to explore the response mechanism of vegetation NEP to dry and wet conditions response mechanism. The results showed the following: (1) Compared with the annual changes, the vegetation NEP changes in the rainy season differed significantly on the karst geographic divisions, in which there was a significant increasing trend in Southwest China (SC) and its karst areas, while a significant decreasing trend in the Indochina Peninsula (IP) and its karst areas. (2) DFMI was the main driver of vegetation NEP change, of which the contributions were 38.05 % and 32.82 % at the annual scale and in the rainy season, respectively, which drove the increase in SC vegetation NEP, and the decrease in IP; note that the increase in vapor pressure deficit (VPD) was the key factor causing the decrease in NEP in the IP karst area during the rainy season. (3) In the lagged effect of drought on vegetation NEP, the time scale of the lag was found to be 1 month. The study revealed differences in the changes in the vegetation carbon sinks in different karst geographic divisions. We obtained a new finding: a significant trend of decreasing vegetation NEP in the IP and its karst area was influenced by the long-term effects of changes in DFMI and VPD. Therefore, the variability of different karst areas, as well as changes in drought and water resources, should be considered in carbon-cycle regulation and vegetation restoration efforts in karst areas.

Sustainable Demoethical values as tools for social transformation in interaction with the components of demography, democracy, and demoeconomics

This study aims to evaluate theories and ideas about social values and determine the high quality of virtues that potentially change social practices, thinking, self-awareness, and behavior of the individual and society. The relevance of the study of value components is determined by the fact that such values as “spirituality and morality”, “responsibility”, “justice”, “rationality”, and “security” are capable of capturing the greatest value of many interests, which allows for the integration of society. An experimental study was conducted using sociological research methods based on developed questionnaires with questions touching on the parameters of sustainable development of society, determining the high quality of virtues and behavior of the individual and society. The study was conducted from May to June 2023 (N = 1387). Based on Demoethical values, special attention is paid to global problems related to climate change and inefficient use of energy and water resources, thereby achieving the Sustainable Development Goals. As a result of the study, Demoethical values are revealed in interaction with the economic components of demography, democracy, and demoeconomics as a tool for social transformation, as they shape the harmonious vision of the world, human behavior, decisions, and relationships with other people.

Estimation of glacier-stored freshwater volume present in major tributaries of the Brahmaputra basin.

Estimation of the glacier-stored freshwater is important to understand the water security in the Himalayan region. While previous work has studied the western and central Himalayan glaciers, the eastern counterpart received less and more scattered attention. In this study, an attempt is made to quantify the total glacier-stored freshwater in the Brahmaputra basin and later compared with previous global models. Using open-source tools such as COSI-Corr and the Himalayan Glacier Thickness Mapper (HIGTHIM), the surface velocity and thickness of 1075 glaciers (> 1 km2) in the Brahmaputra basin were estimated, resulting in a current ice-volume estimate of 283 × 109 m3. Based on the laminar flow model, the mean ice volume ranges from 8284 to 230,186 m3, with an average of 36,570 m3. Sub-basin-wise evaluations of the total glacier-stored freshwater availability in the basin were also conducted, revealing that the Siang (89.998 × 109 m3, 31.45%) and Lohit (84.371 × 109 m3, 29.49%) sub-basins have significantly larger ice volumes than others. The average mean ice volume for each sub-basin are as follows: Teesta (45,233 m3), Sankosh (45,552 m3), Manas (39,581.7 m3), Subansiri (40,922.4 m3), Kameng (41,241.2 m3), Siang (36,120.5 m3), Dibang (31,792.2 m3), and Lohit (30,340.6 m3). Teesta, Sankosh, and Manas exhibit relatively higher average mean ice volumes than others. In comparison with the global studies, the present study's findings are acceptable with ensemble ice-volume estimates considering an uncertainty of ± 17.35%. Therefore, these results serve as a primary input for assessing the future changes in water resources and hazards related to water in the Brahmaputra basin.

Effects and Consequences of Climate Change on the Natural Conditions of Mirzachol District

This article examines the effects and consequences of climate change on the natural conditions of Mirzachol district. Through an in-depth analysis of climate data, ecological studies and socio-economic impacts, the study highlights significant changes in temperature, precipitation and extreme weather events in recent decades. These changes have led to changes in local ecosystems, agricultural productivity, and water resources, challenging the county’s predominantly agricultural economy. The paper also discusses existing adaptation strategies and mitigation efforts and recommends additional measures to increase resilience to future climate change.

СУ ҚАУІПСІЗДІГІ: ФОРСАЙТ-ЗЕРТТЕУЛЕР ПРИЗМАСЫ АРҚЫЛЫ НЕГІЗГІ АСПЕКТІЛЕР МЕН ПЕРСПЕКТИВАЛАР

In the modern world, water security issues are becoming increasingly relevant and are key to ensuring the sustainable development of society. The world community faces serious challenges related to the threats of pollution of water sources, climate change, ecosystem instability and inefficient management of water resources. Solving these problems requires not only immediate measures, but also long-term strategies that can ensure the preservation of water security for the future. The research work is an analytical review of current problems in the field of water security and possible strategic solutions to solve them using foresight research methods. The article highlights the current threats and challenges facing water resources in the modern world, and discusses the advantages and effectiveness of applying foresight research methods in this area. Within the framework of the conducted scientific research, the key areas of strategic planning for ensuring water security in the future are highlighted through the highlighted through the analysis of the current state and forecasting potential changes in the water sector.

Changes of blue and green water in arid inland dissipation area based on coupled surface water and groundwater model

Study regionThe Mainstream in the Tarim River Basin, Southern Xinjiang, China Study focusClimate change and human activities have significantly altered the water cycle, and water security evaluation and management are urgent. In arid and semi-arid areas, the assessment of blue and green water is particularly important. In this study, the MIKE SHE model is used to simulate the spatial and temporal changes of blue and green water resources in the mainstream of the Tarim River Basin (TRB) from 1990 to 2050 under land use and climate change conditions. The scarcity and vulnerability of blue-green water are introduced to evaluate the water security of the basin. The impacts of different land uses on blue-green water resources were also calculated according to the model zoning. New hydrological insights for the regionThe results indicate that from 1990 to 2050, blue water resources show a spatial pattern of gradual decrease from upstream to downstream. Compared to blue water, green water is dispersed more evenly over space. Future climatic scenarios will impact water security, as will changes in blue and green water security in terms of time and space. By comparing the influence of ecological water transport on the change of blue and green water before and after 2000, it was found that environmental water transport plays a certain role in improving the blue water scarcity in downstream of the TRB. The study is significant in maintaining regional water security and ecosystem stability.

The Relationship of the Change in Hydrogeochemical Features and Lithium Values of Kızılırmak Basin (Nevsehir-Central Anatolia) Water with Tectonic Fields

In this study, in particular, the relationship between high lithium values and geological environments was examined. To determine this, the geology, structural geology, hydrogeology, and hydrogeochemistry of the area in the north of the Gülşehir-Yeşilöz sub-basin of the Kızılırmak Basin were investigated. For hydrogeological studies, 19 water samples were collected in May and September. Tectonically, this area has a horst-graben structure. The relationships between the water analysis values of the study area and the tectonic areas were investigated. In particular, the lithium content of the waters in the study area was investigated. Hydrogeochemical properties and seasonal changes in water resources were studied in detail, and their relationship with tectonic areas was evaluated. Water analyses were carried out during wet and dry periods to determine temporal hydrogeochemical changes. According to the analysis, the waters in the area are of Ca-HCO3 and Ca-Mg-HCO3 facies. In addition, there are water samples with high lithium content in the study area. IDW and Kernel diagrams of these were prepared. It was found that these high values were influenced by the rocks formed in the ancient sea and saline lake environments. The region with the highest lithium value is in the formations that represent the former salt lake environment. High lithium (Li) values are generally higher in the region within the Kızılırmak graben. Lithium values in this area were determined as 241.3 µg/L, 154.5 µg/L, 155.2 µg/L, 156.8 µg/L, and 155.6 µg/L.

Impact of precipitation change in the Yangtze River source area on groundwater from the perspective of ground-based and satellite-based observations

In the context of global climate change, the hydrological cycle of the Yangtze River source area has produced significant changes. It is of great practical value to study the influence of regional precipitation changes and precipitation events on regional water resources, especially groundwater. This study uses base flow segmentation and GRACE groundwater reserve calculation technology to examine precipitation’s spatial and temporal variation, especially extreme precipitation events, in the Yangtze River source area. The events analyzed were the extreme precipitation-runoff-base flow response from the Yangtze River source, the extreme precipitation-terrestrial water (surface water and groundwater) response, and the comparison of these events. The findings indicated that extremely strong precipitation, maximum precipitation for five consecutive days, days of moderate rain and above moderate rain intensity precipitation, the longest number of precipitation days, and other extreme precipitation indices had a significantly increasing trend and increased intensity of extreme precipitation events, the regional differences in precipitation trended less significantly. The base flow index gradually increased at a rate of 0.0014 yr-1, suggesting the overall increase of water resources and the contribution rate of groundwater to the runoff was an increased trend . There is a high correlation between the change of water resources in the source area and the change of precipitation, and the increased precipitation influenced an increase in groundwater and regional water resources. These findings inform current knowledge of precipitation-groundwater response mechanisms in alpine and arid regions such as the Qinghai-Tibet Plateau.

Evaluation of water supply function in the Economic Belt of the Northern Slope of the Tianshan Mountains based on the InVEST model

The Economic Belt of the Northern Slope of the Tianshan Mountains (EBNSTM) is a composite ecosystem with mountains, oases, and desert areas; it also serves as an active area for anthropogenic activities. Frequent changes in soil and water resources have significant impacts on regional ecosystems. However, research on the ecosystem water yield function of EBNSTM is relatively limited; additionally, the spatiotemporal variations in the water supply function based on land use changes have not been sufficiently elucidated. This study aimed to explore the land use changes and the spatial variability of water supply service functions in the region at the macro level and uses the land transfer matrix as an important tool to study the changes in land use in the different years of 2000, 2005, 2010, 2015, and 2020. Using the InVEST model, we conducted a quantitative assessment and comprehensive study on the water supply function of EBNSTM across the aforementioned years. Additionally, the study delved into the structure of ecosystem service functions, alongside investigating the spatial and temporal variability of ecosystem services under the multi-scale units of administrative divisions, ecological zones, and land classes. We found that during the 20-year period, the area of construction land of EBNSTM increased by 1089 km2, with the highest dynamic change rate of 4.09 %; 2015–2020 period was the most drastic period of change for each land use type. The average multi-year depth of water production was 87.49 mm, totaling 71.59 × 108 m3. The spatial distribution pattern of the water supply function in the study area during the last 20 years consistently exhibited a distinct pattern: mountainous areas displayed the highest water supply capacity, followed by oases, and deserts ranked the lowest. Further, the water supply service function within the study area is currently experiencing a modest rate of increase. The rate of change in water supply depth was 2.76 mm/a, while the rate of change in water supply volume was 0.47 × 108 m3/a. Areas with enhanced water supply capacity are mostly distributed in the southeast of EBNSTM, whereas the northwest, encompassing the mountainous areas, exhibited a declined water supply capacity. Between 2000 and 2020, the water supply capacity in the study area was ranked as follows: woodland > grassland > unutilized land > cultivated land > urban construction land, with woodland displaying the strongest water supply capacity. When woodlands, grasslands, and croplands were converted to other land use types, their water supply functions generally decreased, and vice versa. Our findings provide a scientific basis for the sustainable management of water and soil resources in EBNSTM.

Methodological approaches to assessing the risks of water resources depletion in the context of climate change (using plain territories of Ukraine as an example)

The relevance of the work is determined by the necessity of quantitative assessment of the risks of water resources changes occurring in the early 21st century due to the greenhouse effect and corresponding climate changes. To evaluate climate risks the authors used a probabilistic approach which involves multiplying the indicator of water resource reduction by the probability of such event occurrence. Reduction of water resources caused by warming characterizes their "depletion". The study utilized the results of calculations of the average long-term annual "climate" runoff, determined through the "climate-runoff" model based on meteorological data of the averaged model trajectory of the EURO-CORDEX project for the climate change scenarios RCP4.5 and RCP8.5. The calculation period extends from 2021 to 2050, while the baseline period continues from the beginning of observations until 1989. The comparison of the calculated climatic runoff and the baseline runoff was performed across meteorological stations. The assessment of the changes was carried out by calculating the relative deviation between the baseline and calculated runoff values. The probability of the "depletion" stage for water resources was determined as the ratio of the number of meteorological stations (grid nodes) where changes reached certain magnitudes to the total number of stations considered. The threshold indicators for the degree of depletion of water resources included changes exceeding 10% (statistically significant changes in water resources), 50% (water resources destruction), and 70% (irreversible destruction of water resources). The objective of the study consists in developing criteria for calculating climate risks and establishing the risks of formation of a tense, critical, and catastrophic state of water resources, taking Ukraine as an example. A detailed examination of the intervals of changes in water resources showed that the highest risk of their depletion over the period from 2020 to 2050 will be observed in the range from -20 to -40% (tense state) for the RCP4.5 scenario and from -30 to -60% (tense state) for the RCP8.5 scenario. It was established that the climate risks of depletion and irreversible depletion of water resources for the territory of Ukraine from 2020 to 2050 remain quite small, which is confirmed by the low probability of their occurrence. However, the risk values increase by 1.5 to 2.0 times for the RCP8.5 scenario compared to the RCP4.5 scenario. Additionally, for calculating the climate risks, it was proposed to use a relative area subject to depletion as an indirect indicator of losses (a larger area implies higher costs of restoration). This approach allowed for having more differentiated risk assessments. The developed methodology for assessing the climate risks of water resources depletion in the context of global warming can be applied for various models and countries.

Land use & land cover dynamics and its relationship with nitrate pollution in groundwater around inactive mine areas using geospatial techniques, SW part of Cuddapah basin, Southern India

Geospatial maps can show how the ineffective operations of inactive mines affect water and aquifer quality. As such, the purpose of this study is to assess the impact of mining and irrigation on the aquifer ecosystem through the evaluation of LULC and slope maps through the application of Landsat 8 OLI/TIRS and DEM data. A total of 50 groundwater samples were prepared from villages in the close proximity to inactive mines during pre and post monsoon periods in 2021. The results of the analysis revealed alarming statistics, that 14% of groundwater samples exceeded the WHO nitrate limit in pre & post monsoon season, indicating a high-risk in the study area. According to guidelines (USEPA, 2014), 34% in pre-monsoon and 26% post-monsoon of samples exceeded the THI levels for adults and children respectively, indicating non-carcinogenic health risks. In addition, 80% of the samples in both seasons exhibited high NPI values, indicating nitrate contamination associated with blue baby syndrome. From the Geospatial analysis the findings from the LULC classification indicate that there has been a significant increase in cropland area from 2016 to 2021 due to changes in forest land, fallow land, and water resources. These problems have been exacerbated by the expansion of cultivated land, which has increased from 71.1 square kilometers in 2016 to 118 square kilometers in 2021, accounting for 13.1% of the total area. This expansion, coupled with elevated water body resource availability, has compounded the nitrate pollution including in intensely irrigated regions. The slope map analysis revealed that the inactive mines occur at low slope, high rainfall areas and these are compounded by runoff from other sources such as domestic and agricultural wastes. For these matters, sealing and remediating these inactive mines is essential so as to prevent further nitrate leakage.

A dynamic surface water extent service for Africa developed through continental-scale collaboration

Spatially explicit, near real time information on surface water dynamics is critical for understanding changes in water resources, and for long-term water security planning. The distribution of surface water across the African continent since 1984 and updated as every new Landsat scene becomes available is presented here, and validated for the continent for the first time. We applied the Water Observations from Space (WOfS) algorithm, developed and well-tested in Australia, to every Landsat scene acquired over Africa since the mid 1980s to provide spatial information on surface water dynamics over the past 30+ years. We assessed the accuracy of WOfS using aerial and satellite imagery. Four regional geospatial organisations, coordinated through the Digital Earth Africa Product Development Task Team, conducted the validation campaign and provided both the regional expertise and experience required for a continental-scale validation effort. We assessed whether the point was wet, dry, or cloud covered, for each of the 12 months in 2018, resulting in 34,800 labelled observations. As waterbodies larger than 100 km2 are easy to identify with Landsat resolution data and can thus boost accuracy, these were masked out. The resulting overall accuracy of the water classification was 82%. WOfS in Africa is expected to be used by ministries and departments of agriculture and water across the continent, by international organisations, academia, and the private sector. A large-scale collaborative effort, which included regional and technical skills spanning two continents was required to create a service that is regionally accurate and is both hosted on, and implemented operationally from, the African continent.

Assessments of various precipitation product performances and disaster monitoring utilities over the Tibetan Plateau

The Tibetan Plateau, often referred to as Asia’s water tower, is a focal point for studying spatiotemporal changes in water resources amidst global warming. Precipitation is a crucial water resource for the Tibetan Plateau. Precipitation information holds significant importance in supporting research on the Tibetan Plateau. In this study, we estimate the performance and applicability of Climate Prediction Center Merged Analysis of Precipitation (CMAP), Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG), Global Land Data Assimilation System (GLDAS), and Global Precipitation Climatology Project (GPCP) precipitation products for estimating precipitation and different disaster scenarios (including extreme precipitation, drought, and snow) across the Tibetan Plateau. Extreme precipitation and drought indexes are employed to describe extreme precipitation and drought conditions. We evaluated the performance of various precipitation products using daily precipitation time series from 2000 to 2014. Statistical metrics were used to estimate and compare the performances of different precipitation products. The results indicate that (1) Both CMAP and IMERG showed higher fitting degrees with gauge precipitation observations in daily precipitation. Probability of detection, False Alarm Ratio, and Critical Success Index values of CMAP and IMERG were approximately 0.42 to 0.72, 0.38 to 0.56, and 0.30 to 0.42, respectively. Different precipitation products presented higher daily average precipitation amount and frequency in southeastern Tibetan Plateau. (2) CMAP and GPCP precipitation products showed relatively great and poor performance, respectively, in predicting daily and monthly precipitation on the plateau. False alarms might have a notable impact on the accuracy of precipitation products. (3) Extreme precipitation amount could be better predicted by precipitation products. Extreme precipitation day could be badly predicted by precipitation products. Different precipitation products showed that the bias of drought estimation increased as the time scale increased. (4) GLDAS series products might have relatively better performance in simulating (main range of RMSE: 2.0–4.5) snowfall than rainfall and sleet in plateau. G-Noah demonstrated slightly better performance in simulating snowfall (main range of RMSE: 1.0–2.1) than rainfall (main range of RMSE: 2.0–3.8) and sleet (main range of RMSE: 1.5–3.8). This study’s findings contribute to understanding the performance variations among different precipitation products and identifying potential factors contributing to biases within these products. Additionally, the study sheds light on disaster characteristics and warning systems specific to the Tibetan Plateau.

Streamflow in the United States: Characteristics, trends, regime shifts, and extremes

Long-term streamflow observations contain essential information for understanding hydrological changes and managing water resources. A continental-scale dataset or analysis of temporal streamflow change is still lacking across hydrologic gauges in the Conterminous United States (CONUS). Here, we compiled 70 years of streamflow records from 1951 to 2021 at ~ 8000 hydrologic stations across the CONUS and characterized temporal trends, regime shifts, and extreme events using a Bayesian time series analysis algorithm. We found that the occurrences of sudden streamflow changes (e.g., regime shifts and extreme events) have been increasing with time across the CONUS. In addition, we derived 181 streamflow indicators that are valuable for hydrological and biological applications, such as the duration and frequency of high or low streamflow events. The Mississippi River Basin, especially the middle and lower parts, was a hot spot of high-frequency high-flow events. Overall, we anticipate the dataset generated here offers valuable information for understanding and quantifying changes in water resources across the CONUS.

Changes in monthly surface area, water level, and storage of 194 lakes and reservoirs in the Yangtze River Basin during 1990–2021 using multisource remote sensing data

Long-term, high spatiotemporal resolution of surface water area, water level, and storage changes in the Yangtze River Basin (YRB) has great scientific and practical importance for improving the management of water resources. Here, three distinct area estimations were first derived using the water classification enhancement method, automated water extraction method based on random forest, and the modified normalized difference water index. The optimized area data was determined by comparing against Sentinel-2 with the minimum root mean square error. A new area data was constructed with the optimized area as the primary data, while the remaining datasets were employed to fill in gaps. The elevation-area relationship was used to derive monthly water level. Changes in water storage were calculated by applying the pyramidal frustum formula from surface water area and water level data. Finally, a new comprehensive dataset of the monthly area, level, and storage changes in the 119 lakes and 75 reservoirs across the YRB with area larger than 10 km2 from 1990 to 2021 were first reconstructed. The spatiotemporal trends of surface water area/level/storage in lakes and reservoirs over 11 sub-basins of the YRB were quantified from 1990 to 2021, as well as before (1990–2003) and after (2003−2021) the construction of the Three Gorges Dam (TGD). During 1990–2021, there was a marked decrease in surface water area/level/storage in most of the YRB sub-basins, which contain 79 % of the lakes and 30 % of the reservoirs. After TGD was constructed, the surface water in lakes decreased by 10 %, while that of reservoirs remained consistent with the pre-construction. The surface water area/level/storage in the lower sub-basins of YRB exhibited a decline to an upward trend before and after the construction of TGD. This study provides a new comprehensive dataset for understanding the dynamic changes of water resource and climate change.

Improvement of Climate Resource Utilization in the Southwestern Hilly Region through the Construction of a New Multi-Maturing Cropping System

The construction of an appropriate cropping pattern is crucial for the improvement of regional agricultural economic efficiency and sustainable development. Despite previous efforts, there remains a gap in optimizing cropping patterns that fully leverage climate resources to enhance production efficiency. This study addresses this gap by systematically comparing the differences in climate resource allocation, production efficiency and crop response among models by constructing four new triple-maturing cropping models at typical ecological sites in the hilly areas of southwest China. To solve the above problems, we constructed eight cropping patterns and classified them to three as follows: the Traditional Double Cropping System, the Traditional Triple Cropping System, the Novel Triple Cropping System. The results showed that the new multi-maturing planting pattern was significantly better than the traditional two-maturing netting pattern and the traditional three-maturing planting pattern in terms of light, temperature and water productivity. Compared with the traditional two-maturity net cropping model and the traditional three-maturity cropping model, the new cropping model increased light energy productivity by 97.88% and 50.00%, respectively; light energy use by an average of 0.48% and 0.31%; cumulative temperature productivity by an average of 84.70% and 49.14%; and rainfall productivity by an average of 101.04% and 49.61%. An assessment of the light, temperature and water meteorological resource use efficiency of the different treatments showed that the resource use efficiency of the new multi-maturing planting pattern was on average 111.58% and 74.78% higher than that of the traditional two-maturing net planting pattern and the traditional three-maturing planting pattern, with the T6 pattern having the highest resource use efficiency. The new multi-ripening cropping pattern has demonstrated production stability in response to changes in light, temperature and water resources, better adapting to weekly climate changes, stabilizing yields and improving efficiency. In summary, the results of this study can provide a theoretical basis for optimizing cropping patterns and promoting the use of climate resources in agriculture and sustainable development. Future research should focus on further refining these models, exploring their adaptability to various climatic conditions, and evaluating their long-term economic and environmental impacts.

Quantifying and communicating uncertain climate change hazards in participatory climate change adaptation processes

Abstract. Participatory processes for identifying local climate change adaptation measures have to be performed worldwide. As these processes require information about context-specific climate change hazards, we show in this study how to quantify climate change hazards with their uncertainties in regions all around the globe and how to best communicate the potential hazards with their uncertainties in order to identify local climate change adaptation strategies. In a participatory process on water-related adaptation in a biosphere reserve in Germany, we used the freely available output of a multi-model ensemble provided by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) initiative, which provides global coverage, to quantify the wide range of potential future changes in (ground)water resources. Our approach for quantifying the range of potential climate change hazards can be applied worldwide for local to regional study areas and also for adaptations in agriculture, forestry, fisheries, and biodiversity. We evaluated our approach to communicating uncertain local climate change hazards by means of questionnaires that the stakeholders in the participatory process and the audiences from the general public of two project result presentations answered. To support the stakeholders in participatory climate change adaptation processes, we propose the use of percentile boxes rather than boxplots for visualizing the range of potential future changes. This helps the stakeholders identify the future changes they wish to adapt to, depending on the problem (e.g., resource scarcity vs. resource excess) and their risk aversion. The general public is best informed by simple ensemble averages of potential future changes together with the model agreement on the sign of change. Using or adapting our quantification and communication approach, flexible climate change adaptation strategies can and should be developed worldwide in a participatory and transdisciplinary manner, involving stakeholders and scientists.