Dew Formation Research Articles

Assessment of dew harvesting as a sustainable water source and air quality indicator: a case study of Dhanbad, Jharkhand, India

ABSTRACT Dew formation takes place when atmospheric water vapor condenses on the surface which cools down due to radiation deficit. As it is a local phenomenon, its study gives information about the pollutants present in the atmosphere. Also, since dew formation is a natural phenomenon, and involves passive cooling, this can be a potential method for atmospheric water harvesting. The main intention of this present research work was the collection of dew samples and their analysis for yield and chemical composition. Dew samples were collected on a self-fabricated dew collection set up during the winter season. In total 30 dew samples were collected and analyzed for ionic constituents. The results were then compared to those of rain samples. The pH of dew was found to be in the range of 7-8.7, showing the neutral to alkaline nature of dew. Ionic compositions were higher in dew than in rain. While sulfate largely contributed to the ion composition of dew, nitrate was the least contributing ion. The average concentration for sulfate and nitrate in dew were found to be 0.55 and 0.03 meq/L, respectively. The average yield of dew was found to be 0.13L/m2. This yield value from the simplest of collection set-up ensures that dew can be considered as the potential water source with advanced condensing material and passive/active cooling in arid and semi-arid regions.

Moisture Transformation in Warm Air Intrusions Into the Arctic: Process Attribution With Stable Water Isotopes

AbstractWarm Airmass Intrusions (WAIs) from the mid‐latitudes significantly impact the Arctic water budget. Here, we combine water vapor isotope measurements from the MOSAiC expedition, with a Lagrangian‐based process attribution diagnostic to track moisture transformation in the central Arctic Ocean during two WAIs, under contrasting sea‐ice concentrations (SIC). During winter with high SIC, two moisture supplies are identified. The first is Arctic moisture, locally‐sourced over the sea ice, with isotopic composition influenced by kinetic fractionation during ice‐cloud formation and vapor deposition. This moisture is rapidly overprinted by low‐latitude moisture advected poleward during WAI. In summer under low SIC, moisture is supplied through evaporation from land and ocean, with moisture removal via liquid‐cloud and dew formation. The isotopic composition reflects the influence of higher relative humidity at the evaporation sites. Given the projected increase of frequency and duration of WAIs, our study contributes to assessing process changes in the Arctic water cycle.

Forecasting Trends in Relative Humidity in Iraq (Study in Climate Geography)

The research aims to predict and determine the trend in relative humidity rates (%) in Iraq, for four months (October, January, April, July), as the percentage of water in the atmosphere does not exceed (0.01%) of the hydrosphere at any moment. Despite this, it is an important element in the weather and plays a major role in the formation of clouds, fog, and dew. He is responsible for all major weather events, such as hurricanes and other weather disturbances. To understand the nature of the behavior of relative humidity, its trend, fluctuations, and future changes in time and space, statistical models were designedm(SARIMA) based on the Box–Jenkins method in the time series forecasting method for the period (2023-2037), for the following stations (Kirkuk - Baghdad - Al-Hayy - Samawah - Nasiriyah - Basra) and relying on the base years from (1970 - 2022), and the research adopted the use of The algorithm drawn up by two researchers (BJ 1976), used the autoregressive model and the seasonal integration moving average, which is symbolized by the symbol (p, d, q) (P, D, Q) SARIMA, which is called the seasonal multiplier model.

Diurnal asymmetry of surface albedo in a semi‐arid grassland over the China's Loess Plateau

AbstractIn current land surface models or satellite remote sensing retrievals, clear‐sky surface albedo (α) is usually assumed to be symmetrical and relies only on the solar elevation angle (SEA). Based on 1‐min high‐resolution measurements of surface radiation fluxes, this study demonstrated that the diurnal variations of clear‐sky surface albedo exhibited a significant asymmetrical pattern in both summer and winter seasons over a semi‐arid grassland of the China's Loess Plateau. The results indicated that α values in the morning were generally larger than those in the afternoon at the same SEA, and diurnal asymmetry of surface albedo was distinctly prominent with SEA <40° in summer (before 9:30 a.m.) or SEA <20° in winter (before 10:00 am), and tended to diminish at midday. The averaged morning/afternoon albedo differences under sunny days were 0.05 (30.4%) and 0.09 (37.8%) in summer and winter seasons, respectively. Air relative humidity was positively correlated with the diurnal asymmetry of surface albedo, ascribed to probable formation of dew in the morning. Depression of the dew point was negatively linked to the morning/afternoon albedo differences, which was attributed to the strong scattering of incident sunlight by dewdrops could enhance the morning surface albedo. Such diurnal asymmetry of surface albedo should be included in the parameterization scheme of mesoscale and region‐scale climate models in the semi‐arid areas of China's Loess Plateau.

Assessment of the synergy of hydrophobicity and thermal conductivity in epoxy/graphite oxide composite coatings

AbstractIn various industrial applications, especially within the internal pipes of heat exchanger devices, there is a crucial need for surface coatings that offer both superhydrophobic properties and high thermal conductivity. Achieving the balance between these two characteristics is essential for optimizing heat transfer performance along metal pipe walls and mitigating the formation of water droplets on the surface. This research focuses on the development of polymer composite coatings to address these dual requirements, providing protection against humid environments, resistance to dew formation, and simultaneous enhancement of thermal conductivity. The key challenge lies in selecting a coating type that provides low surface energy and polarity, thereby achieving the desired hydrophobic properties while also maintaining adequate thermal conductivity. This study formulates polymer composite coatings utilizing laser‐modified epoxy resin and strategically integrates graphite oxide particles. These graphite particles undergo modification through oxidation to enhance compatibility with epoxy. In conjunction with graphite oxide modification, the resulting laser‐modified coatings exhibit super‐hydrophobic characteristics with an enhanced water contact angle of 162° and a low contact angle hysteresis (<5°). Furthermore, the epoxy/graphite oxide composite coatings demonstrate improved thermal conductivity, marking a significant 261% increase compared to pure epoxy, elevating it from .234 to .846 W/mK.

Dew, frost, fog and lifted temperature minima: Observations in southern England and implications for modelling

AbstractGiven difficulties with modelling radiation fog and the similarity of meteorological conditions linked to dewfall and frost we investigated the formation of dew, frost and fog. For a site in the UK seven years of data were analysed representing high‐resolution atmospheric profiles and dew meter measurements for radiation nights with stable conditions. Classical dewfall occurs by condensation when the surface is below the dew point and cooler than the air above. However, the profiles show that, in the absence of fog, typically dew and frost form with the surface warmer than the immediately overlying air due to lifted temperature minima (LTMs) at about 0.15 m. Observations of aerosol number density and average hydrated radii show that aerosol optical extinction (and hence their radiative effect) is weakly but significantly correlated with the intensity of LTMs. Low wind speed on stable nights allows settling of aerosols which radiatively cool the air near the ground more quickly than the surface cools – thus creating LTMs. In the presence of LTMs typically dew and frost form not by condensation, but by occult deposition of water droplets onto the canopy and ground. Among radiation fog observations, 91% are associated with light near‐surface winds and LTMs. When the rate of removal of suspended water droplets by occult deposition generating dew or frost is too slow, then build‐up of droplets in the air just above the surface leads to the formation of radiation fog. Future modelling should allow for the accumulation of near‐surface aerosols and their radiative effects during stable nights to represent the formation of LTMs. Modelling of typical dew and frost will require representation of occult deposition. Assessing rates of occult deposition compared to rates of generation of suspended water droplets is needed to forecast the onset of radiation fog formed near the ground.

An Effective and Affordable Internet of Things (IoT) Scale System to Measure Crop Water Use

Scales are widely used in many agricultural applications, ranging from weighing crops at harvest to determine crop yields to regularly weighing animals to determine growth rate. In agricultural research applications, there is a long history of measuring crop water use (evapotranspiration [ET]) using a particular type of scale called weighing lysimeters. Typically, weighing lysimeters require very accurate data logging systems that tend to be expensive. Recent developments in open-source technologies, such as micro-controllers and Internet of Things (IoT) platforms, have created opportunities for developing effective and affordable ways to monitor crop water use and transmit the data to the Internet in near real-time. Therefore, this study aimed to create an affordable Internet of Things (IoT) scale system to measure crop ET. A scale system to monitor crop ET was developed using an Arduino-compatible microcontroller with cell phone communication, electronic load cells, an Inter-Integrated Circuit (I2C) multiplexer, and analog-to-digital converters (ADCs). The system was powered by a LiPo battery, charged by a small (6 W) solar panel. The IoT scale system was programmed to collect data from the load cells at regular time intervals and send the data to the ThingSpeak IoT platform. The system performed successfully during indoor and outdoor experiments conducted in 2023 at the Clemson University Edisto Research and Education Center, Blackville, SC. Calibrations relating the measured output of the scale load cells to changes in mass resulted in excellent linear relationships during the indoor (r2 = 1.0) and outdoor experiments (r2 = 0.9994). The results of the outdoor experiments showed that the IoT scale system could accurately measure changes in lysimeter mass during several months (Feb to Jun) without failure in data collection or transmission. The changes in lysimeter mass measured during that period reflected the same trend as concurrent soil moisture data measured at a nearby weather station. The changes in lysimeter mass measured with the IoT scale system during the outdoor experiment were accurate enough to derive daily and hourly crop ET and even detect what appeared to be dew formation during the morning hours. The IoT scale system can be built using open-source, off-the-shelf electronic components which can be purchased online and easily replaced or substituted. The system can also be developed at a fraction of the cost of data logging, communication, and visualization systems typically used for lysimeter and scale applications.

A Novel Method for the Quantitative Evaluation of Retrograde Condensate Pollution in Condensate Gas Reservoirs

During the development of condensate gas reservoirs, the phenomenon of retrograde condensation seriously affects the production of gas wells. The skin factor caused by retrograde condensation pollution is the key to measuring the consequent decrease in production. In this study, a multiphase flow model and a calculation model of retrograde condensate damage are first constructed through a dynamic simulation of the phase behavior characteristics in condensate gas reservoirs using the skin coefficient, and these models are then creatively coupled to quantitatively evaluate retrograde condensation pollution. The coupled model is solved using a numerical method, which is followed by an analysis of the effects of the selected formation and engineering parameters on the condensate saturation distribution and pollution skin coefficient. The model is verified using actual test data. The results of the curves show that gas–liquid two-phase permeability has an obvious effect on well production. When the phase permeability curve changes from the first to the third type, the skin coefficient increases from 3.36 to 26.6, and the condensate precipitation range also increases significantly. The distribution of the pollution skin coefficient also changes significantly as a result of variations in the formation and dew point pressures, well production, and formation permeability. The average error between the calculated skin of the model and the actual test skin is 3.87%, which meets the requirements for engineering calculations. These results have certain significance for guiding well test designs and the evaluation of condensate gas well productivity.

Characteristics of dew/hoar frost from Artemisia ordosica and bare soil based on weighing lysimeters in a semi-arid region

Dew and hoar frost are important water resources in arid and semi-arid regions. However, knowledge of the characteristics of dew/hoar frost formation in the typical shrub canopy of Northwestern China and its importance for vegetation survival is still not clear as it is difficult to observe. In this study, we investigated dew/hoar frost formation characteristics under both Artemisia ordosica and bare soil conditions based on weighing lysimeters in Mu Us Sandy Land, Northwest of China. The results show that dew and hoar frost occurred 214 days for Artemisia ordosica and 162 days for bare soil. The hoar frost formation mainly occurs from October to March, while dew formation occurs every month. The amount of hoar frost was 19.6 mm under Artemisia ordosica condition and 17.4 mm under bare soil condition, and the amount of dew was 27.5 mm of Artemisia ordosica and 18.4 mm of bare soil. The most common daily amount of dew/hoar frost is between 0 and 0.2 mm, which accounts for 60.7 % and 52.5 % of dew/hoar frost formation days for the Artemisia ordosica and bare soil conditions, respectively. The results from boosted regression tree analysis indicated that relative humidity had the greatest influence on dew/hoar frost formation. During soil drought periods (July 15 to August 18, 2021), the soil water content of Artemisia ordosica kept constant at 0.061 cm3/cm3, while the soil water content of bare soil was dropped at the rate of 0.00135 (cm3/cm3)/d. The ratio of dew amount of Artemisia ordosica to rainfall amount was 42.1 %. Despite the small amount of dew, it serves as a frequent and important supplementary water source for the ecosystem. This study provided valuable insights into dew/hoar frost formation, especially its importance for vegetation survival.

Severe photochemical pollution formation associated with strong HONO emissions from dew and guttation evaporation

The unknown daytime source of HONO has been extensively investigated due to unexplained atmospheric oxidation capacity and current modelling bias, especially during cold seasons. In this study, abrupt morning increases in atmospheric HONO at a rural site in the North China Plain (NCP) were observed almost on daily basis, which were closely linked to simultaneous rises in atmospheric water vapor content and NH3 concentrations. Dew and guttation water formation was frequently observed on wheat leaves, from which water samples were taken and chemically analyzed for the first time. Results confirmed that such natural processes likely governed the daily nighttime deposition and daytime release of HONO and NH3, which have not been considered in the numerous HONO budget studies investigating its large missing daytime source in the NCP. The dissolved HONO and NH3 in leaf surface water droplets reached 1.4 and 23 mg L−1 during the morning on average, resulting in averaged atmospheric HONO and NH3 increases of 0.89 ± 0.61 and 43.7 ± 29.3 ppb during morning hours, with relative increases of 186 ± 212 % and 233 ± 252 %, respectively. The high atmospheric oxidation capacity contained within HONO was stored in near surface liquid water (such as dew, guttation and soil surface water) during nighttime, which prevented its atmospheric dispersion after sunset and protected it from photodissociation during early morning hours. HONO was released in a blast during later hours with stronger solar radiation, which triggered and then accelerated daytime photochemistry through the rapid photolysis of HONO and subsequent OH production, especially under high RH conditions, forming severe secondary gaseous and particulate pollution. Results of this study demonstrate that global ecosystems might play significant roles in atmospheric photochemistry through nighttime dew formation and guttation processes.

Revisiting an ecophysiological oddity: Hydathode-mediated foliar water uptake in Crassula species from southern Africa.

Hydathodes are usually associated with water exudation in plants. However, foliar water uptake (FWU) through the hydathodes has long been suspected in the leaf-succulent genus Crassula (Crassulaceae), a highly diverse group in southern Africa, and, to our knowledge, no empirical observations exist in the literature that unequivocally link FWU to hydathodes in this genus. FWU is expected to be particularly beneficial on the arid western side of southern Africa, where up to 50% of Crassula species occur and where periodically high air humidity leads to fog and/or dew formation. To investigate if hydathode-mediated FWU is operational in different Crassula species, we used the apoplastic fluorescent tracer Lucifer Yellow in combination with different imaging techniques. Our images of dye-treated leaves confirm that hydathode-mediated FWU does indeed occur in Crassula and that it might be widespread across the genus. Hydathodes in Crassula serve as moisture-harvesting structures, besides their more common purpose of guttation, an adaptation that has likely played an important role in the evolutionary history of the genus. Our observations suggest that ability for FWU is independent of geographical distribution and not restricted to arid environments under fog influence, as FWU is also operational in Crassula species from the rather humid eastern side of southern Africa. Our observations point towards no apparent link between FWU ability and overall leaf surface wettability in Crassula. Instead, the hierarchically sculptured leaf surfaces of several Crassula species may facilitate FWU due to hydrophilic leaf surface microdomains, even in seemingly hydrophobic species. Overall, these results confirm the ecophysiological relevance of hydathode-mediated FWU in Crassula and reassert the importance of atmospheric humidity for some arid-adapted plant groups.

Laser-based remote detection of leaf wetness

Pesticide-free agricultural strategies need new tools for disease prevention. Better than early detection of disease, detection of conditions favorable to their appearance can be a progress. In the case of fungal diseases, the presence of water on the plant surface is necessary. In order to detect remotely this presence early and at the scale of a crop field, we propose a low-cost solution based on laser reflection. Here, experimental results in a controlled environment are presented on both hydrophobic and hydrophilic leaves (rapeseed Brassica Napus and grapevine Vitis Vinifera, respectively). We first assess the water detection on a leaf surface by recreating the dew formation process. We next evaluate the influence of the scanning measurement and leaf inclination on the detection to get closer to in-field conditions. Results show that this method is very sensitive on both types of leaves. Water detection is possible from a low surface coverage with a high temporal precision at 1 m. In the hydrophobic case, water on a leaf surface leads to an increase of the detected signal up to three times compared to a dry leaf. The corresponding minimum surface coverage detectable at 1 m is evaluated at 1.6% thanks to 2D ray-tracing numerical simulations. In the hydrophilic case, on the contrary, water on a leaf surface leads to a decrease of the detected signal by almost half. For both types, the dew detection delay is contained under 5 min and can be improved. Finally, the presented results pave the way to a field application.

Dew Formation and Anaerobiosis in Anaerobic Jars

Introduction: This study aimed to prove whether the palladium catalyst affects the dew formation time in the anaerobic cover and whether anaerobiosis can be achieved without a palladium catalyst.
 Materials and Methods: This research is a laboratory experimental study with a non-randomized control group design. In this study, replication was carried out. The amount of replication used is 10. The palladium catalyst was used in 10 experiments, whereas it was not used in ten other experiments.
 Results: The growths of Pseudomonas aeruginosa, Clostridium tetani, and Bacteroides fragilis were observed after 48-hour incubation. The time of appearance of water condensate was observed until 24-hour incubation. The time of appearance of water condensate in the palladium-contained anaerobic jar varied between 1.37 minutes and 3.33 minutes. On the other hand, water condensate did not appear in the without-palladium anaerobic jar. No growth of Pseudomonas aeruginosa was observed in the palladium-contained anaerobic jar; on the contrary, there were ten growths in the anaerobic jar without palladium. Eight growths of Clostridium tetani were observed in the palladium-contained anaerobic jar, whereas there was no growth without palladium. No growth of Bacteroides fragilis was observed in the without-palladium anaerobic jar, whereas seven growths were observed in the anaerobic jar containing palladium. The time of appearance of water condensate in the palladium-contained anaerobic jar was different from that in the anaerobic jar without palladium. Significant differences (p < 0,01) in anaerobiosis creation between the palladium-contained anaerobic jar and the without-palladium anaerobic jar were also clearly observed.

Seasonal variations and sources of the dew from stable isotopes in alpine meadows

AbstractThe dew is closely related to the micro‐use water of plants and the large‐scale hydrological processes, its formation on grassland plays a vital role especially in maintaining the eco‐hydrological cycle. We used structural equation modelling to investigate how environmental factors would affect dew formation on alpine graminoid‐Kobresia meadow in northern Qinghai‐Tibet Plateau. The stable isotope information of dew, ambient vapour, soil water, plant water, creek water and precipitation were tracked to explore the source of dew, the dew transport route of the six dominant species by Mix SIAR model. Our results showed that the frequency of dew on the graminoid‐Kobresia meadow in 2020 and 2021 was 42.86% and 45.83%, respectively. Both atmospheric pressure (r = 0.4) and temperature (r = 0.382) showed significant positive effects dew formation while wind speed (r = −0.309) had a negative effect. The contribution rates of soil water, plant water and ambient water vapour to dew were 48.20 ± 5.46%, 38.30 ± 5.07%, and 13.50 ± 1.82%, respectively. The proportion of dew utilization in the dominant species had no significant species differences. Our results provided an improved understanding of dew formation based on isotope technology on alpine meadow in northern Qinghai‐Tibet Plateau.

Surfaces with modified morphology and wettability arrangement: a potential medium for water harvesting in desertification areas

Abstract The cost of water transport for irrigating drought-endurable plants in desertification areas makes it important to develop other water sources. Research shows that freshwater produced by dewing could satisfy the water requirement during germination of desert plants, therefore, functional materials that promote dew formation provide solutions for reduction of plant irrigation costs in desertification regions. In this review, feasibility of utilizing trace irrigation for ensuring survival of desert plants has been demonstrated. The technologies of preparing water harvesting materials with modified microstructure and wettability arrangement have been introduced, it has been shown that surface embedded with a bump array which has counter wettability compared with its plane section is a common morphology adopted by current works. After comparing climates in desertification regions with those in dewing chambers, it has been found that currently, the expected values of dew productivities of most water harvesting materials in deserted areas will not be as efficient as they performed in experiments due to low relative humidity. However, hydrophobic surface with submicron scale hydrophilic spherical cavity array produced by nanosphere lithography has shown reliable prospects in reducing the energy barrier of heterogeneous nucleation and thus become a more potential medium in dew water production.

EFFECT OF ETHYLENE COMPOUNDS ON BANANA RIPENING AND POST-HARVEST PACKAGING (STORAGE) OF CITRUS FRUITS

Ethylene compounds are used in the post-harvest handling of horticultural products to speed up the ripening process. Suitable storage and packaging would maintain the quality of horticultural products. Horticultural products undergo further metabolism even after harvesting such as transpiration, respiration, maturation, and ripening. To prevent the rapid deterioration of horticultural produce (physical, nutritional, and sensory), postharvest handling requires proper ethylene dosing, proper packaging, and storage of the product during handling. The aim of this research was to observe and find out the effect of the ripening stage on bananas and how to package orange fruits on changes in quality (physical and sensory) during post-harvest storage. The results showed that there was an influence of ethylene compounds on the ripening process of bananas on sensory characteristics, the color changed from yellow to blackish brown, the aroma became more fragrant and the sweet taste became sweet and sour; increasing the value of total suspended solids (TSS) and decreasing the weight of bananas. Plastic packaging equipped with perforated holes also affects the quality of oranges, lower orange fruit weight loss, and better sensory characteristics in texture and color compared to oranges packaged in plastic without holes. Hence, the storage of oranges fruits in air-tight conditions is not recommended due to it can make CO2 to be trapped and accumulate in the packaging which can result in the formation of water droplets or dew that affect the quality of orange fruits.

The different effects of regional and local winds on dew formation in the Negev desert

Abstract With dew serving as an important water source for various small organisms and plants in deserts, knowledge regarding the spatial distribution of dew (which constitutes an important fraction of the non-rainfall water, NRW) is of prime importance. This is also the case for the Negev dew desert. According to the classical model, local nocturnal katabatic winds that descend down the slopes during the night to the wadi beds are responsible for the accumulation of cold air, subsequently triggering dew formation in the wadis. Nevertheless, NRW measurements that were conducted in a one-order drainage basin in the Negev during the dewy season (late summer and fall) yielded half the amount in the wadi bed in comparison to the hilltop, attributed to the sheltered position of the wadi from the cooling effect of the regional (sea-breeze) winds, which are not considered by the classical model. Hypothesizing that the classical model may however take place at wide wadi where the sea breeze winds are not sheltered, measurements of dew and temperatures were periodically carried out at the beds of a 5 m-wide narrow (NW) and a 200 m-wide (WW) wadi beds and at the hilltop (HT). The findings did not fully support our hypothesis. In comparison to the hilltop, and despite the mutual effect of the katabatic and the sea breeze winds on the wide wadi bed, also the wide wadi exhibited lower amounts of dew than that of the hilltop, with NRW following the pattern HT > WW > NW. The overwhelming effect of the sea-breeze winds was also supported indirectly by periodic NRW and temperature measurements during the winter during which the sea breeze does not commonly take place. Evidence suggests that whereas the classical model takes place during the winter during which the katabatic winds may play a central role in dew formation, the occurrence of the sea breeze (regional wind) during the late summer and fall overshadows the effect of the local katabatic winds. Our findings point to the possibility that the classical model may not adequately predict dew formation in regions subjected to sea-breeze winds.

Analysis of Architectural Needs for Passive Low-Tech Fog and Dew Collector Building Design: A Narrative Literature Review

Global warming and climate change have negative effects on life on earth. One of the consequences is a water crisis or water scarcity, both in quantity and quality. Indonesia also cannot avoid this problem. Therefore it is necessary to prepare an alternative water supply solution, one of which is from water vapor (atmospheric water), especially in the form of dew and fog. This study aimed to formulate the design requirements for passive low-tech dew and fog collector building by comparing several technologies and projects in the world that have been realized recently that have a relationship with architectural science. This research used qualitative research with a narrative literature review approach. This research produced design requirements in the form of principles and technical requirements in designing and realizing dew and fog collector building, especially in terms of function, construction, and appearance.Keywords: dew collector, fog collector, low-tech, water scarcity, architecture

Identifying key stages of radiation fog evolution using water vapor isotopes

Fog is tied to surface energy and water budgets. However, our knowledge about the processes leading to fog evolution is still fragmentary, and their adequate representation in numerical-weather-prediction and climate models remains challenging. Water vapor isotopes are widely used to investigate Earth's water cycle dynamics and can provide process-based insights into fog evolution. Although isotopes of water vapor and droplets during radiation fog have been reported, the intra-event isotope dynamics and the mechanisms controlling water vapor isotope variability during radiation fog evolution have hardly been investigated. We use water vapor isotopes (δ2Hv, dv) combined with meteorological and eddy-covariance measurements, plus vertical profiles from a high-resolution numerical-weather-prediction model (COSMO-1), to study the processes that influence radiation fog evolution. Variability in surface-humidity and water vapor isotopes is tied to the different stages (shallow, transitional, and deep fog) of radiation fog evolution and affected by condensation, turbulent entrainment, fog droplet deposition at the surface, and evaporation processes. Strong water vapor isotopic fluctuations during radiation fog are linked to fog lifting to stratus-clouds during nighttime that lead to fog dissipation at ground level. Our results reveal highly correlated atmospheric-specific-humidity (qa) and water vapor isotopes during dew formation which is typical before the onset of radiation fog and in combination with fog; whilst during fog periods, δ2Hv and dv show larger temporal variability than qa due to their sensitivity to fog dynamics. Particularly, during fog growth, entrainment of air from the fog-top caused increasing dv, which was otherwise constant during condensation. Furthermore, δ2Hv variability during the transition into deep fog likely indicated the alternation of condensation-induced-decrease and entrainment-induced-increase of δ2Hv. Compared to the temporal isotope variability (with a magnitude of 34.6‰ for δ2Hv) associated with large-scale cold-frontal-clouds, radiation fog evolution is found to be associated with isotope variability of a similar amplitude (24.6‰ for δ2Hv).

Physico chemical analysis of a pond water at the bank of which crackers are exploded during Chhath puja in Bihar.

To assess the magnitude of degradation of water of a rural pond near a temple, where fire crackers are every year exploded at the occasion of Dipawali and Chhath Puja in Bihar, the physico-chemical analysis was done before and after the festival. Water sample of the pond was collected and experiments like determination of total dissolved substances, the electrical conductivity, total alkalinity, presence of chlorides, sulphide, elements like magnesium, iron, phosphorous, sodium, potassium, calcium, nitrate etc. were analyzed per the standard methods mentioned in the book. For calculation of dissolved oxygen, water sample was fixed at the point of collection of water. Similarly, free carbon dioxide was also determined of pH was observed at the site of the pond. Findings of the present work clearly revealed that there were discrepancies in the data for all parameters selected for study. For study, before and next day of the festival where countless fire crackers were exploded at the bank. This indicated that the residues of the fire crackers formed after explosion. Finally cause down in the pond water along with the dew drops as this festival is celebrated in winter where dew formation takes place.