Advanced Fog Harvesting Method by Coupling Plasma and Micro/Nano Materials

Harvesting fog is a potential and effective way to alleviate the crisis of water resource shortage. A highly efficient and economical fog harvesting method has always been a global and common goal. Here, a promising fog harvesting method by coupling plasma and micro/nano materials is proposed, which can achieve 93% fog collection efficiency with consuming power of only 0.76 W/0.04 m2. The basic method is to utilize nanoparticles to decorate both the discharge electrode and the collecting electrode of the micro/nano electrostatic fog collector. For the discharge electrode, the nanoparticles can achieve an order of magnitude higher electric field strength and a 28.6% decrease in the operating voltage (14 kV decreases to 10 kV). For the collecting electrode, a novel composite structure of hydrophobic/hydrophilic (HB/HL) is proposed. The core advantage is the directional droplet transport at the junction of HB and HL caused by surface tension can adjust the accumulated droplets on the two sides, which avoids the droplet residue and mesh blockage in the general structure. This technology provides an innovative approach for the collection of microdroplets and a new design idea for the fog collector to deal with the water crisis.

[Characteristics of climate change and its impacts on water resources in Qilian Mountains, China]

Qilian Mountains, is an important ecological function area, an important ecological security barrier, the river runoff region in Northwest China, as well as a sensitive area to global climate change and fragile area of ecological environment. The ecological environment in this area played an important role in the economic development of Northwest China. Based on the observation data of temperature and precipitation in Qilian Mountains, MOD10A2 snow products and the flow data of Shiyang River, Heihe River and Shule River, we systematically analyzed the characteristics of climate change from 1961 to 2020, and the impacts of climate change on water resources under the scenario of climate warming. The results showed that, from 1961 to 2020, the annual average temperature increased significantly, with the rate reaching 0.39 ℃·(10 a)^-1. The warming rate was the highest in the western part of Qilian Mountains, followed by the middle and eastern regions. The warming trend was the strongest in winter and the lowest in spring. The average temperature changed abruptly in 1997. The annual average precipitation increased with flucturation, with a rate of 10 mm·(10 a)^-1, which increased most obviously in the middle of Qilian Mountains. After 2004, it entered a rainy period, with a warm and humid trend. The precipitation in the four seasons showed an increasing trend and the increase of precipitation in summer contributed the most to the annual precipitation. Annual precipitation was dominated by interannual scale change, and the contribution rate of 2.8-year was approximately 64.3%. The snow cover of Qilian Mountains was obviously affected by temperature and snowfall, which was negatively correlated with summer temperature and positively correlated with snowfall. From 2016 to 2020, the temperature increase had slowed down in Qilian Mountains, the snowfall had increased, and the snow cover tended to increase. After 2000, the temperature and precipitation increased more obviously, the meltwater from glacier and snow increased, the mountainous runoff of Shiyang River, Heihe River and Shule River had an increasing trend. Our findings are of great significance to the construction of ecological civilization and coping with climate change in Qilian Mountains.

Long-Term Monitoring of Noxious Bacteria for Construction of Assurance Management System of Water Resources in Natural Status of the Republic of Korea

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.

Monitoring the Snowpack Volume in a Sinkhole on Mount Lebanon using Time Lapse Photogrammetry

Lebanon has experienced serious water scarcity issues recently, despite being one of the wealthiest countries in the Middle East for water resources. A large fraction of the water resources originates from the melting of the seasonal snow on Mount Lebanon. Therefore, continuous and systematic monitoring of the Lebanese snowpack is becoming crucial. The top of Mount Lebanon is punctuated by karstic hollows named sinkholes, which play a key role in the hydrological regime as natural snow reservoirs. However, monitoring these natural snow reservoirs remains challenging using traditional in situ and remote sensing techniques. Here, we present a new system in monitoring the evolution of the snowpack volume in a pilot sinkhole located in Mount Lebanon. The system uses three compact time-lapse cameras and photogrammetric software to reconstruct the elevation of the snow surface within the sinkhole. The approach is validated by standard topographic surveys. The results indicate that the snow height can be retrieved with an accuracy between 20 and 60 cm (residuals standard deviation) and a low bias of 50 cm after co-registration of the digital elevation models. This system can be used to derive the snowpack volume in the sinkhole on a daily basis at low cost.

[Characteristics of hydrogen and oxygen isotopes in precipitation and moisture sources in Gaoyou, Jiangsu Province, China]

It is necessary to examine the characteristics of hydrological cycle in Gaoyou area of Jiang-su Province in response to climate change and flood disasters. In this study, 121 atmospheric rain samples were collected and environmental factors were recorded from July 2015 to October 2017. We analyzed the hydrogen and oxygen stable isotopic composition of rain and identify moisture sources in this area. Results showed that the hydrogen and oxygen isotopic composition of rain had an seasonal variation, which was positive in the winter but negative in the summer. D-excess value was higher in winter than that in summer. On the annual scale, significantly negative relationships between δD (δ¹⁸O) and temperature and between δD (δ¹⁸O) and precipitation indicated the "anti-temperature effect" and "precipitation amount effect", respectively. On the seasonal scale, there was no obvious "temperature effect" but "precipitation amount effect" in autumn and winter. Results from the HYSPLIT model showed that the precipitation in this area came mainly from ocean evaporation that was influenced by the Chinese South Sea, Indian Ocean and Pacific Ocean. Precipi-tation in other seasons mainly came from the water vapor mixture from the Eurasian continent, Atlantic Ocean, Arctic Ocean, as well as local evaporation. The seasonal pattern of δD and δ¹⁸O values in precipitation was mainly influenced by monsoon activity and El Niño-Southern Oscillation (ENSO). In addition, the precipitation isotopes clearly indicated the shift in climates from El Niño to La Niña.

Shannon Entropy for Measuring Spatial Complexity Associated with Mean Annual Runoff of Tertiary Catchments of the Middle Vaal Basin in South Africa

This study evaluates essentially mean annual runoff (MAR) information gain/loss for tertiary catchments (TCs) in the Middle Vaal basin. Data sets from surface water resources (WR) of South Africa 1990 (WR90), 2005 (WR2005) and 2012 (WR2012) referred in this study as hydrological phases, are used in this evaluation. The spatial complexity level or information redundancy associated with MAR of TCs is derived as well as the relative change in entropy of TCs between hydrological phases. Redundancy and relative change in entropy are shown to coincide under specific conditions. Finally, the spatial distributions of MAR iso-information transmission (i.e., gain or loss) and MAR iso-information redundancy are established for the Middle Vaal basin.

Environmental Change in the Agro-Pastoral Transitional Zone, Northern China: Patterns, Drivers, and Implications

Chengde city is located in the agro–pastoral transitional zone in northern China near the capital city of Beijing, which has experienced large-scale ecological construction in the past three decades. This study quantitatively assessed the environmental changes in Chengde through observation records of water resources, water environment, atmospheric environment, and vegetation activity and investigated the possible causes. From the late 1950s to 2002, the streamflow presented a downward trend induced by climate variability and human activities, with contribution ratios of 33.2% and 66.8%, respectively. During 2001–2012, the days of levels I and II air quality presented clear upward trends. Moreover, the air pollutant concentration was relatively low compared with that in the adjacent areas, which means the air quality has improved more than that in the neighboring areas. The water quality, which deteriorated during 1993–2000, began to improve in 2002. The air and water quality changes were closely related to pollutant emissions induced by anthropogenic activities. During 1982–2012, the vegetation in the southeastern and central regions presented restoration trends, whereas that in the northwestern area showed degradation trends. The pixels with obvious degradation trends correlated significantly with annual mean temperature and annual precipitation. Ecological engineering also played a positive role in vegetation restoration. This analysis can be beneficial to environment managers in the active response and adaptation to the possible effects of future climate change, population growth, and industrial development and can be used to ensure sustainable development and environmental safety.

Fog as a fresh-water resource: overview and perspectives

The collection of fog water is a simple and sustainable technology to obtain fresh water for afforestation, gardening, and as a drinking water source for human and animal consumption. In regions where fresh water is sparse and fog frequently occurs, it is feasible to set up a passive mesh system for fog water collection. The mesh is directly exposed to the atmosphere, and the foggy air is pushed through the mesh by the wind. Fog droplets are deposited on the mesh, combine to form larger droplets, and run down passing into a storage tank. Fog water collection rates vary dramatically from site to site but yearly averages from 3 to 10 l m(-2) of mesh per day are typical of operational projects. The scope of this article is to review fog collection projects worldwide, to analyze factors of success, and to evaluate the prospects of this technology.