Affect Water Resources Research Articles

Spatio-temporal patterns and trends of streamflow in water-scarce Mediterranean basins

Abstract. The issue of water scarcity, exacerbated by climate change and demographic increase, has become a growing concern in many regions throughout the world. Understanding hydrological behaviour to promote resilient and sustainable water management is paramount. Hydrological models that integrate natural processes and anthropogenic alterations of the basin's hydrology are a powerful tool to support decision-making. We developed a SWAT+ hydrological model including stakeholder expert knowledge on water management and introducing a novel calibration and validation approach suitable for heterogeneous basins in space and/or time. We also assessed spatio-temporal patterns and trends of streamflow during the first 2 decades of the 21st century in the Catalan River Basin District, in the western Mediterranean, using a wide variety of indicators to fully characterize the hydrological regime. We calibrated and validated the model using data from 50 gauging stations, verifying the usefulness of the new calibration and validation strategy. Co-development with stakeholders and the integration of expert knowledge, most notably on reservoir operations, helped improve model performance. Results revealed a generalized streamflow reduction, as well as increased dominance of streamflow flashiness and zero-flow recurrence. We also observed differences in seasonal trends, with autumn being the most affected season. These results provide insights into how climate change and anthropogenic pressures are going to keep affecting water resources availability in the future, thus raising the need for sustainable management practices in the Catalan River Basin District, as well as other regions vulnerable to water scarcity.

Assessing road construction effects on turbidity in adjacent water bodies using Sentinel-1 and Sentinel-2

Road construction significantly affects water resources by introducing contaminants, fragmenting habitats, and degrading water quality. This study examines the use of Remote Sensing (RS) data of Sentinel-1 (S1) and Senitnel-2 (S2) in Google Earth Engine (GEE) to do spatio-temporal analysis of turbidity in adjacent water bodies during the construction and operation of the E18 Arendal-Tvedestrand highway in southeastern Norway from 2017 to 2021. S1 radiometric data helped delineate water extents, while S2-Top of Atmosphere (TOA) multispectral data, corrected using the Modified Atmospheric correction for INland waters (MAIN), used to estimate turbidity levels. To ensure a comprehensive time series of RS data, we utilized S2-TOA data corrected with the MAIN algorithm rather than S2-Bottom Of Atmosphere (BOA) data. We validated the MAIN algorithm's accuracy against GLORIA (Global Observatory of Lake Responses to Interventions and Drivers) observations of surface water reflectance in lakes, globally. Subsequently, the corrected S2 data is used to calculate turbidity using the Novoa and Nechad retrieval algorithms and compared with GLORIA turbidity observations. Findings indicate that the MAIN algorithm adequately estimates water-leaving surface reflectance (Pearson correlation > 0.7 for wavelengths between 490 and 705 nm) and turbidity (Pearson correlation > 0.6 for both algorithms), determining Nechad as the more effective algorithm. In this regard, we used S2 corrected images with MIAN to estimate turbidity in the study area and evaluated with local gauge data and observational reports. Results indicate that the proposed framework effectively captures trends and patterns of turbidity variation in the study area. Findings verify that road construction can increase turbidity in adjacent water bodies and emphasis the employing RS data in cloud platforms like GEE can provide insights for effective long-term water quality management strategies during construction and operation phases.

Spatial and temporal variations in temperature and precipitation trends in South Korea over the past half-century (1974–2023) using innovative trend analysis

This study analyzed temperature and precipitation from 60 meteorological stations during a half-century (1974–2023) using the Innovative Trend Analysis (ITA) to explore the spatial and temporal trends across South Korea. The ITA illustrated the trends graphically, and the Mann-Kendall (MK) test added statistical significance to these findings, allowing us to better understand climate changes over the past five decades. The ITA analysis showed a statistically significant monotonic warming trend in temperature at nearly all of the stations. While annual and seasonal changes were found to be substantial, the most relative increases were reported during the spring and summer months. There were quite clear spatial and seasonal differences in precipitation trends. The Han River and Jeju Island areas showed significant increases in precipitation during summer and autumn, which may be associated with intensified monsoonal activity. Our findings revealed a consistent warming signal in all regions and significant regional climate variability. The observed temperature increases, especially in the spring season, are likely to have significant impacts on crop yield and altered growing season due to increased heat stress, increased water demand for various activities affecting water resources, heightened risks to public health from heatwaves and broader impacts on societal well-being such as increased energy demands as well as economic costs associated with climate adaptation measures. The complex precipitation patterns revealed the influence of regional topography and oceanic drivers in modulating climate variability in South Korea, which differs from patterns seen in more continental regimes.

Environmental impact of modern agricultural practices: Strategies for reducing carbon footprint and promoting conservation

Modern agricultural practices have significantly transformed food production, leading to increased efficiency and productivity. However, these advancements have also had notable environmental impacts, particularly concerning carbon emissions and resource depletion. This study explores the environmental impact of contemporary agricultural practices, emphasizing the need for strategies to mitigate carbon footprints and enhance conservation efforts. Agriculture contributes substantially to greenhouse gas emissions through sources such as livestock, synthetic fertilizers, and fossil fuel consumption. These emissions contribute to climate change and global warming. Additionally, modern farming practices often lead to deforestation, habitat loss, and soil degradation, exacerbating biodiversity loss and reducing soil health. Water usage in agriculture also poses significant challenges, with high water consumption and pollution from runoff affecting water resources and aquatic ecosystems. To address these issues, several strategies can be employed to reduce the carbon footprint of agriculture. Adoption of sustainable farming practices such as conservation tillage and no-till farming can enhance soil carbon sequestration, improving soil health and reducing emissions. Agroforestry and cover cropping further contribute by capturing atmospheric carbon and improving soil structure. The integration of renewable energy sources like solar and wind power in farming operations, along with energy-efficient technologies, can also reduce reliance on fossil fuels and lower overall greenhouse gas emissions. Promoting conservation involves implementing practices that protect and restore natural resources. Soil conservation methods, including erosion control techniques like terracing and contour plowing, help maintain soil health and prevent degradation. Efficient water management strategies, such as drip irrigation and rainwater harvesting, reduce water consumption and mitigate pollution from runoff. Biodiversity conservation can be supported through the preservation of natural habitats and the promotion of biodiverse farming systems, which enhance ecosystem resilience and stability. Effective policy frameworks and support mechanisms are crucial for driving the adoption of these strategies. Government policies, including environmental regulations and incentives, play a pivotal role in encouraging sustainable practices. Research and innovation are essential for developing new technologies and practices, while education and extension services ensure the dissemination of knowledge and best practices to farmers. Modern agricultural practices have significant environmental impacts, but through the adoption of sustainable practices and innovative strategies, it is possible to reduce carbon footprints and promote conservation. Continued research, supportive policies, and effective implementation of conservation strategies are essential for achieving a more sustainable agricultural future. Keywords: Environmental Impact, Agricultural Practices, Carbon Footprint.

Analysis of Pre-monsoon and Post-monsoon Seasonal Rainfall Trends by Mann-Kendall and Sen’s Slope Estimator Test in Himachal Pradesh, India

The purpose of the current study is to determine the trends and patterns of precipitation occurring in the periods before and after the monsoon season at 12 meteorological stations located in the twelve districts of the Himachal Pradesh region. The timeframe of the analysis is from 1991 to 2020. For this study, we used the Mann-Kendall test and estimator Sen's slope estimator test. Precipitation is an essential climatic factor that can act as a signal of climate change. In order to understand how climate change may affect water resource planning and management, it is crucial to understand rainfall pattern. The results indicate that there is a growing tendency in the pre-monsoon season at some sites, while some stations are seeing a declining trend. Keylong has the most significant falling trend, with a Sen slope of -4.154mm whereas Manali had the highest increasing trend at Sen's Slope (1.471mm). In contrast, the analysis of post-monsoon season data reveals an upward tendency in all studied regions, except for Dharamshala, where Sen's slope (-0.042mm) shows a slight downward trend whereas Manali had the highest increasing trend with the value of 1.771mm. According to the research, agricultural and horticultural sectors in Himachal Pradesh are at risk from heavy rainfall and landslides during the periods before and after the monsoon season, respectively, if the patterns continue to rise. Conversely, a decrease in these patterns might result in water scarcity. To tackle adverse climate changes, the general public must embrace adaptation measures based on long-term series data.

Catchment-scale network analysis of functional sediment connectivity during an extreme rainfall event in the Grastal catchment, Austrian Central Alps

Global warming significantly impacts sediment dynamics in glaciated catchments, affecting water resource operations, water quality, recreational activities, and ecological systems. The propagation of climate-change-induced geomorphic changes and the catchment's sediment yield are moderated by sediment connectivity, defined as the degree to which a geomorphic system facilitates sediment transfer. Quantifying functional sediment connectivity at the catchment scale remains a challenge. To address this, we propose a novel approach combining graph theory with the morphological method. This approach is exemplified through a detailed case study of a 2022 thunderstorm event in the Grastal valley, Tyrol, Austria. First, a graph of potential sediment cascades is constructed using a geomorphological map, a digital elevation model and a flow routing algorithm. A short-term Digital Elevation Model of Difference (DoD) from consecutive ALS surveys is then used to infer sediment fluxes and calculate the Sediment Delivery Ratio (SDR) for each landform. The primary sediment mobilising processes were debris flows and fluvial erosion, with a significant proportion of debris flow material being deposited on slopes, not reaching the fluvial corridor. Strong fluvial erosion was observed in the proglacial area, but the propagation of these geomorphic changes is halted by an alluvial fan and a lake. Most landforms can be clearly categorised as connecting or disconnecting features based on their SDR. In total, a maximum of 12 % of mobilised sediments exited the catchment. Our findings demonstrate that (i) short-term, catchment-wide DoDs are valuable for assessing functional connectivity at an event temporal scale, (ii) using landforms as fundamental spatial units allows for the identification and in-depth analysis of critical sediment sinks and sources, and (iii) graph analysis facilitates the catchment-wide calculation of sediment delivery ratios between meaningful fundamental units and the delineation of significant sediment cascades.

Concerns over Lithium, Water, and Climate in Earth’s Two Highest Deserts

Brine mining to meet resource demands amid renewable energy transitions is affecting water resources in South America and China. Hydrologists can help understand how and join the search for solutions.

The effect of dietary changes on the water and carbon footprints in China

Dietary changes impact the production and consumption of plant and animal foods, thereby affecting water resource usage and greenhouse gas emissions. However, previous studies have ignored subnational differences in long-term dietary changes and environmental impacts. This study evaluated the environmental impacts of dietary changes in China from 1997 to 2016 by combining water and carbon footprints. Results indicated significant provincial differences in both total food consumption amounts (277.15 Mt to 445.58 Mt) and patterns. At the national level, water consumption and greenhouse gas emissions of 10 main food items rose sharply from 437.52 ± 131.26 Gm3/yr to 671.13 ± 201.34 Gm3/yr and 273.66 ± 26.43 Mt CO₂ eq. to 443.50 ± 46.96 Mt CO₂ eq. As per capita animal-based food consumption first increased and then decreased, more developed regions with balanced diets showed water-saving and carbon reduction effects. For instance, Beijing reduced its water footprint by 50.44 m3/cap/yr and reduced carbon footprint by 186.05 kg CO₂ eq./cap/yr. In contrast, in less developed regions, animal food consumption has continued to grow over the last two decades, weighing the environmental impacts. Dietary changes in more developed regions can serve as references for less developed areas. Ensuring steady growth in animal food consumption for basic health needs can also support sustainable development. Furthermore, scenario analysis indicated that replacing all meat with plant-based food could achieve maximum water saving by 13 % and maximum emission reduction by 32 % with current energy and nutritional requirements, while towards national dietary guidelines would increase water consumption by 449.43 m3/cap and emissions by 8.48 CO2 eq./cap, dominated by increasing fruits and vegetables. Policies that affect consumers' choices of food patterns could focus more on promoting adequate and appropriate animal food intake towards healthy and environmentally friendly diets, particularly in less developed regions.

Using an integrated hydro-economic model to determine the drought and energy relationship in the Upper Euphrates Basin

ABSTRACT Decreasing precipitation in the Upper Euphrates Basin and the negative impact of climate change directly affect water resources and hydroelectricity generation in the basin. This basin, which contains the largest dams in terms of hydroelectricity generation potential, requires research studies to assess and characterize drought for risk prevention and mitigation applicable to water resources management. To better assess drought in the upper Euphrates Basin due to recent warming, FEHEM is developed, a hydro-economic optimization model of the integrated reservoir system of the Upper Euphrates Basin. Using a historical hydrological dataset, water management and hydroelectric operations are evaluated with a linear programming model at monthly time steps. This paper uses two different drought indices: (1) the standardized precipitation index, which is based on precipitation alone; and (2) the reconnaissance drought index, which takes into account both evaporation and precipitation. These indices were used to evaluate the impact of temporal drought characteristics in the Upper Euphrates Basin on the hydropower generation of 10 dams with a total installed capacity of over 3255 MW in the basin, based on 45 years of precipitation data from more than a hundred measuring stations in the basin.

High capacity adsorption of antimony by hollow Co-MnO2 and its consequential utilization in SbO2--based aqueous batteries

Toxic metal pollution is one of the environmental problems that seriously affect water resources and ecosystems. Antimony, recognized for its teratogenic and carcinogenic properties, poses significant health risks due to its widespread presence in natural water sources. In this study, cobalt-doped manganese oxide bimetallic composites were designed as an efficient adsorbent for the antimony removal from water. The adsorbent exhibits robust performance over a range of pH values, achieves a significant adsorption capacity of 591.1 mg/g, and exhibits adsorption equilibrium within 25 min. The effectiveness of the adsorption is attributed to the interaction between metal-O bonds and antimony, as well as the hydrogen bonding. In line with the concept of sustainable development, waste adsorbents are used as negative electrodes for SbO2--based aqueous alkaline batteries. It exhibits a high reversible specific capacity of 122.8 mAh·g−1. This research not only sheds light on innovative approaches to antimony removal but also opens up avenues for the sustainable reuse of waste materials, in line with the principles of sustainable development.

The impact of land use and cover changes on river flows in Wundanyi Catchment of Taita Hills, Kenya (1970–2030)

<p>Taita Hills are one of the most important biodiversity hotspots of Kenya but are experiencing a high rate of deforestation due to the to the conversion of its original forestland to agriculture and settlement during the last century. These landscape dynamics, coupled with rainfall fluctuations in these critical ecosystems, may significantly affect water resource distribution and food security in Taita Taveta County and its environs. This study aimed to establish the trends of land use/cover change (LUCC) in the Wundanyi catchment from 1970 to 2030 and predict their specific and combined effects on surface runoff and stream flow in the same period. The analysis was based on statistical trend analysis and dynamic landscape modeling using both historical and primary data from the Wundanyi catchment and Landsat TM and ETM+ imagery of Taita Hills for 1990, 2000, and 2010. Results show highly variable mean seasonal and annual values of discharge in Wundanyi catchment, probably attributed to environmental changes affecting Taita Hills in general and Wundanyi catchment in particular. Compared to 1990, major land use/cover changes in 2010 were featured by the expansion of built-up area (250%), plantation forest (23.7%), broadleaved forest (17.4%), and thicket (15.9%). It was also notable the decrease in woodland (−30.3%), cropland (−21.6%), and shrubland (−0.8%). Dynamic spatial trends by the year 2030 will be evidenced by increased thicket by 0.41% per annum (<em>R</em><sup>2</sup> = 81.6%) and by decreased plantation forests (−0.13%; <em>R</em><sup>2</sup> = 91.3%), woodland (−0.10%; <em>R</em><sup>2</sup> = 77.6%), shrubland (−0.11%; <em>R</em><sup>2</sup> = 85.2%), broadleaved forests (−0.03%; <em>R</em><sup>2</sup> = 56.6%) and cropland (−0.09%; <em>R</em><sup>2</sup> of 84.4). These changes will shape the catchment landscape and influence its hydrology, unless the existing forest and agricultural policy interventions are enforced. Hence, crop diversification, agroforestry, and soil and water conservation structures are recommended to maintain effective control of LUCC on hydrological processes going on in the Wundanyi catchment.</p>

Water Resources Management under Climate Change: A Review

Climate change affects water resources through the decrease in rainfall and the increase in temperatures and evapotranspiration. An indirect impact of climate change is also the increase in water uses by human activities. In this review, 320 papers were retrieved, of which 134, spanning five continents and dealing with impacts and solutions, were selected to be used to better understand the effects of climate change on water resources, ecosystems, human health, security, and socio-economic aspects. Here, suggestions and proposals towards solutions by scientists from around the world, tips and ideas to deal with climate change, and the best solutions for future water management are presented. The main solutions highlighted concern integrated water resource management, political direction, policies, an increase in knowledge, and new technologies. Furthermore, most of the analyzed papers underline that water resource management needs to incorporate the protection and restoration of ecosystems and their services. Nature-based solutions need to be the starting point of new scientific and innovative ways to deal with climate change and look towards future climate adaptation. In this complex evolution of the water resource, the political position of Italy is also shown, illustrating what actions could be implemented for water resource management.

Climate variability and river flow changes in Wundanyi sub-catchment of Taita hills, Kenya

<p>Wundanyi sub-catchment of Taita hills is experiencing a high rate of deforestation due to the conversion of all its original forestland to agriculture and settlement during the last century. The landscape dynamics coupled with rainfall fluctuations in these critical ecosystems may significantly affect water resource distribution and food security in Taita Taveta County and its environs. This study aimed to establish the trends of selected hydroclimatic variables in Wundanyi sub-catchment from 1970 to 2030 and their specific and combined effects on surface runoff and streamflow in the same period. The analysis was based on statistical trend analysis and dynamic landscape modelling using both historical and primary hydroclimatic data from Wundanyi and Voi weather stations. Results show highly variable mean seasonal and annual values of temperature, rainfall, runoff and discharge in both Wundanyi and Voi weather stations. Increasing mean temperatures and rainfall were observed during the long dry season (JJAS), while decreasing seasonal discharges were observed during both the JJAS dry season and the OND short rainy season. These anomalies were pronounced in 1980–1981, 1986–1987 and 1992–1993, probably due to both global and local environmental changes affecting Taita Hills in general and Wundanyi sub-catchment in particular. The predicted effects of rainfall fluctuation were supported by declining surface runoff of 1.3% during JJAS, and an increase of 0.8% during the OND, with similar effects on river discharges. The combined effects of climate variability and Land use and cover changes (LUCC) on surface runoff were estimated to an increase of 200 mm during JJAS and 370 mm during OND, and while river discharges increased by 2.37 m<sup>3</sup>/s and 1.93 m<sup>3</sup>/s during JJAS and OND, respectively. Consequently, natural forest covers have significant control effects on surface runoff and can boost river discharges amid diverse agricultural cropping practices. Hence, crop diversification, agroforestry, and soil and water conservation structures are recommended to maintain effective control of LUCC on hydrological processes going on in Wundanyi sub-catchment.</p>

Understanding future hydrologic challenges: Modelling the impact of climate change on river runoff in central Italy

Central Italy’s diverse ecosystems and landscapes are susceptible to the Mediterranean climate change, affecting water resources and riverine systems. Managing these resources is crucial for the nation’s sustainable development and resilience. This research assesses potential long-term climate change impacts on river runoff in central Italy’s highly regulated Aterno-Pescara River watershed. We simulated current and future river runoff using the Soil and Water Assessment Tool (SWAT+). Climate projections from 5 Global Climate Models (GCMs) under two emissions scenarios are used to quantify potential runoff and drought characteristic changes in SWAT+ to investigate future (2015 – 2100) climate change impacts on river runoff. All GCMs predicted increasing daily temperature (up to 0.6 °C decade−1 at 95 % confidence level) and decreasing precipitation trends (−16.4 mm decade−1), resulting in negative river runoff trends (−0.036 m3s−1 decade−1). Uncertainties exist regarding variable magnitudes among GCMs and scenarios. Analyzing 12-month standardized precipitation and runoff drought indices using projections data revealed a strong correlation between drought indices (Pearson correlation coefficient ranges between 0.63 − 0.93 among GCMs). The run-sum technique for both indices showed potential frequent, severe, and prolonged future droughts, with meteorological droughts possibly lasting up to 105 months (severity 163) and hydrological droughts exceeding 100 months (severity over 150). This study provides crucial insights for central Italy’s policymakers, emphasizing the need for strategies addressing climate change impacts on water resources for future sustainability.

Changing agricultural practices as a result of variable water resource availability in a hilly area of An Giang province, Vietnam

Abstract Located in the Southwest of the Mekong Delta in Vietnam, An Giang province is an important center of agricultural production, especially rice cultivation. Climate change impacts are one of several man-made factors affecting water resource availability for agriculture in the province. It is recognized that new solutions are crucial to adapt to the present and future conditions of a scarcer water supply. This paper explores climate factors affecting water resource availability in agriculture and some recent adaptations being adopted by farmers in one district of An Giang province. Hydro-meteorological data was collected together with in-depth interviews as a tool to point to proximate changes in water status and availability and to evaluate local inhabitants’ awareness of climate risks and adaptive strategies. The results noted that climate factors (temperature, humidity, annual rainfall) have altered over time, causing decreased availability of water supplies for agriculture. Recognizing this situation, both structural adaptation and non-structural solutions may occur simultaneously to maintain agricultural production efficiency. The types of crops, tolerant varieties, and irrigation projects suitable for various geographical areas were considered for more adaptive agriculture production locally. To address some of the problems that farmers face, water-saving technologies are an essential part of a range of potential solutions to maintain agricultural production and protect the environment in the future.

El Niño-Induced Drought Impacts on Reservoir Water Resources in South Africa

The ENSO phenomenon is associated with below average rainfall and influences the climate regime of southern Africa. With the advent of climate change, drought frequencies and magnitudes have worsened in the developing world and this in turn negatively impacts the natural environment and communities’ livelihoods. This study evaluated the relationship between El Niño-induced drought and reservoir water levels over the Albasini Dam Catchment (ADC) areas in Limpopo Province, South Africa. Standardised indices (i.e., SPI and SSI) were used to define drought events over the study area. Mann–Kendall and Sequential Mann–Kendall were used for trends analysis as well as correlation and wavelet coherence to evaluate the relationship between variables of interest. There exists a relationship between El Niño-induced drought event and reservoir water levels. This was shown by the correlation between drought indices and reservoir water levels with the coefficient of determination being stronger at the 12th timescale (i.e., 0.743 and 0.59) compared to the 6th timescale (i.e., 0.07 and 0.44) for both precipitation and streamflow indices, respectively. Wavelet analysis further showed that there existed a phased relationship between the two variables. Although there are other factors that may affect reservoir water resources, these study findings show that El Niño-induced drought also negatively affect water resources. Therefore, this study recommends the development of multidimensional and multiscale management strategies to minimise drought impacts and adaptation in the region.

Global ecosystem responses to flash droughts are modulated by background climate and vegetation conditions

AbstractFlash droughts and their physical processes have received increasing attention in recent years due to concerns about the potential of flash droughts to affect water resources and ecosystems. Yet to date, the response of ecosystems during flash drought events, particularly on a large scale, and the determinants of the ecosystem responses to flash droughts have been underexplored. Here we analyse temporal variations in vegetation anomalies during flash drought events at a global scale between 2001 and 2020 using observation-based leaf area index, gross primary productivity, and solar-induced chlorophyll fluorescence data. We identify divergent ecosystem responses in terms of the timing and intensification of drought-induced vegetation stress across different regions around the world. Furthermore, we find that these regional differences are largely modulated by background climate and vegetation conditions, rather than meteorological conditions, with ecosystems being subjected to more rapidly developing and greater degrees of vegetation stress in arid and short vegetation-dominated regions as compared to humid forests. Our results highlight the spatially heterogeneous ecological impacts of flash droughts, implying the need to comprehensively integrate aspects of both atmospheric and bioclimatic properties in flash drought monitoring and forecasting systems to improve our ability to track their evolution and impacts.

Diurnal to Decadal Variability in Land Surface and Air Temperature Gradient from 2002 to 2022 over the Contiguous United States

Abstract The surface and air temperature gradient (TS00 − Tair) drives the development of the convective boundary layer and the occurrence of clouds and precipitation. However, its variability is still poorly understood due to the lack of high-quality observations. This study fills in this gap by investigating the diurnal to decadal variability in TS00 − Tair from 2002 to 2022 based on hourly observations collected at over 100 stations of the U.S. Climate Reference Network. It is found that TS00 − Tair reaches its maximum at noon with an average of 6.85°C over the contiguous United States, which decreases to 4.28°C when the soil moisture exceeds 30%. The daily minimum of TS00 − Tair has an average of −2.08°C, which generally occurs in the early evening but is postponed as the cloud fraction decreases. Moreover, while existing studies have used the near-surface soil temperature, such as the 5-cm soil temperature (TS05), to calculate TS05 − Tair, we find that TS00 − Tair and TS05 − Tair have opposite diurnal cycles, and their amplitudes differed drastically. The daily minimum of TS00 − Tair has a significant decreasing trend (−0.50° ± 0.007°C decade−1) from 2002 to 2022 due to Tair increasing at a higher rate than TS00 during the nighttime. The occurrence frequency of near-surface stable conditions (TS00 − Tair < 0) increases significantly, and the frequency of unstable conditions (TS00 − Tair > 0) decreases notably throughout the year except for winter. When it is stable, the magnitude of TS00 − Tair tends to decrease while the TS00 − Tair tends to increase when it is unstable, which is consistent with the drying condition caused by the precipitation deficit. This study provides the first observational evidence on how TS00 − Tair responds to warming. Significance Statement The impact of global warming on surface-air temperature gradients is a crucial scientific issue that needs to be addressed. These gradients determine changes in cloud and precipitation, affecting water resources. However, traditional surface temperature measurements from weather stations are of high uncertainty due to direct exposure to the insolation. Satellite retrieval of surface temperature is limited by the availability of clear sky conditions, with low accuracy for temperature gradient calculations. Despite their importance, high-accuracy data of land surface temperature are still lacking. To address this issue, the U.S. Climate Reference Network (USCRN) uses infrared radiometers to continuously monitor surface temperature with high accuracy and sampling frequency. This study reports on surface-air temperature gradients at more than 100 U.S. stations, providing insight into diurnal to decadal variability over the contiguous United States. The study also highlights the significant difference between the land surface temperature–air temperature gradient and soil temperature–air temperature gradient.

Decrease in quality and quantity of clean water due to climate change

Climate change is a world phenomenon that is often discussed recently and has an impact, one of which is an increase in temperature. In addition, previous research says that climate change affects water resources found all over the world, where this temperature change is also enjoyed by the residents. Objectives : The purpose of this research which means to know the impact of climate change (climate change) on the quantity and quality of hygienic water. Water is one of the natural resources that is needed all the time so that it is a very crucial human need. The method that will be carried out in this research is the mix method, namely the Library Study method and the qualitative method using descriptive lighting. with the impact of climate change which causes an increase in air temperature, causing faster evaporation of water, resulting in rapid reduction of groundwater. Conclusion : This reduced groundwater will affect the quantity and quality of hygienic water on earth. The results of this study are expected to be useful for the government and agencies related to the provision of hygienic water. Besides that, other people can learn to understand why there can be a decrease in the quality and quantity of hygienic water.

Analysis of Rainwater Harvesting Methods for Optimizing Small Island Areas: A Case Study in Selaru Island, Indonesia

Water management on islands has an important role because of their limited features. Although each island has different features (size, isolation, geology and topography, climate and hydrology, economic development, etc.) – all affecting water resources and management, all islands face many of the same water-related issues and challenges. This condition is influenced by population growth triggered by the development of natural resources. This research aims to ensure that the rainwater harvesting method as an alternative water source can fulfill distribution deficiencies while maintaining the ecological conditions of small island areas. Water availability is analyzed using the F.J. Mock method, and the existing sources are analyzed using the RWH method. Based on guidelines, the analysis of domestic water needs is 65 L/person/day. The analysis continues with the existing distribution scenario. The results show that the Adaut sub-watershed and the Namtabung sub-watershed are predicted to experience water shortages, and the combined distribution scenario of existing sources and the RWH method can be a solution to overcome water shortages. The RWH method can achieve optimal water distribution in Selaru Island until 2040.