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Warm 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. Plain Language Summary: The movement of warm and moist airmasses from lower latitudes has a big effect on the Arctic climate system. We used data from the MOSAiC drift expedition, where we measured the isotopic composition of water vapor. Water isotopes are powerful tracers of where moisture came from and how it changed during the transport. We focused on two specific warm air intrusions, occurring in February and September 2020 respectively, when the amount of sea ice was different. During the winter, the isotopic composition of the airmasses was primarily influenced by in‐Arctic moisture exchanges over sea ice. This local moisture was swiftly replaced by isotopically‐distinct warmer and moister airmasses coming from lower latitudes during the warm intrusion. In summer, when there was less sea ice, we found that water came mainly from ocean evaporation with additional land evaporation during the air intrusion. The isotopic composition of vapor was influenced by how humid the places it came from were. As warm air intrusions are expected to happen more often and last longer in the future, our study helps us understand how they affect the Arctic water cycle. Key Points: Transformation of moist airmasses and their isotopic composition during warm air intrusions depends on sea‐ice extentIn winter, warm air intrusions suppress ice‐cloud formation and kinetic isotopic fractionation over sea iceIn summer, d‐excess is driven by vapor pressure gradients between ocean skin layer and the lower atmosphere at the evaporative sites [ABSTRACT FROM AUTHOR]

In 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. [ABSTRACT FROM AUTHOR]

Long‐lasting hydrogen evolution and efficient dew harvest is realized via electrospinning a polyvinylidene fluoride (PVDF) membrane on hybrid hydrogels embedded with photocatalytic g‐C3N4/Pt nanosheets. Due to the hindrance of water evaporation by the hydrophobic PVDF membrane, the drying process of the hybrid hydrogels significantly slows down. Hence, the g‐C3N4/Pt nanosheets can continue working on photocatalytic splitting of the water molecules in the hydrogels. When the thickness of the PVDF membrane is 48 μm, the hydrogen evolution rate can reach 2,543 μmol h−1 g−1, which is 38% more than that of the hybrid hydrogel without covering. Therefore, the hybrid hydrogels covered with PVDF membrane are able to work with high efficiency for 12 h, sufficient for hydrogen evolution during the daytime. In addition, the hydrophobic PVDF membrane and hydrophilic hydrogels construct a Janus structure and induce a fast transport of water molecules from the hydrophobic to hydrophilic side. It is beneficial for the rapid collection of dew in the morning. Based on the long‐lasting hydrogen evolution and efficient dew harvest, the present hybrid hydrogels covered with PVDF membrane are very suitable for the environment rich in solar resource and lack of water supply, such as desert or prairie. [ABSTRACT FROM AUTHOR]

It is commonly believed that nonrainfall water (NRW) serves as an important and even a central source of water for biocrusts in arid and semiarid regions. Known also as biological soil crusts, they mainly consist of cyanobacteria (that dwell within the upper 2 mm of the soil) and crustose chlorolichens that commonly protrude 1–2 mm above ground. It is commonly assumed that due to the prolonged dry season in deserts, a constant source of water is required for their survival. Overestimated, nonrealistic NRW values, whether due to the use of improper measurement devices or erroneous interpretation of the recorded values as well as instances during which distillation was regarded as dewfall, supported the notion that the amounts of NRW are sufficiently high to allow for biocrust activation. In the current commentary, a short account of the reasons that led scholars to believe that NRW may be utilized by biocrusts is presented, and the findings that led to this belief are critically analysed. It is argued that the amounts of NRW reaching the surface are below the critical thresholds of 0.05 and 0.1 mm required for net photosynthesis by the chlorolichens and cyanobacteria, respectively. Moreover, it is argued that even if these thresholds are seldom reached, their duration is too short to result in net carbon gain. As shown for the dewy Negev and may be applicable for other arid and semiarid regions, biocrusts rely on rainwater for their growth and survival. [ABSTRACT FROM AUTHOR]

Trichomes are common in plants from dry environments, and despite their recognized role in protection and defense, little is known about their role as absorptive structures and in other aspects of leaf ecophysiology. We combine anatomical and ecophysiological data to evaluate how trichomes affect leaf gas exchange and water balance during drought. We studied two congeneric species with pubescent leaves which co‐occur in Brazilian Caatinga: Croton blanchetianus (dense trichomes) and Croton adenocalyx (sparse trichomes). We found a novel foliar water uptake (FWU) pathway in C. blanchetianus composed of stellate trichomes and underlying epidermal cells and sclereids that interconnect the trichomes from both leaf surfaces. The water absorbed by these trichomes is redistributed laterally by pectin protuberances on mesophyll cell walls. This mechanism enables C. blanchetianus leaves to absorb water more efficiently than C. adenocalyx. Consequently, the exposure of C. blanchetianus to dew during drought improved its leaf gas exchange and water status more than C. adenocalyx. C. blanchetianus trichomes also increase their leaf capacity to reflect light and maintain lower temperatures during drought. Our results emphasize the multiple roles that trichomes might have on plant functioning and the importance of FWU for the ecophysiology of Caatinga plants during drought. Summary statement: We describe a novel pathway of foliar water absorption that involves stellate trichomes, sclereids and pectin protuberances that redistribute water inside the leaf. The absorption of dew water through this pathway benefits the ecophysiological performance of Caatinga plants during drought. [ABSTRACT FROM AUTHOR]

By providing water during the long dry rainless season, non‐rainfall water (NRW), principally dew and fog, is commonly thought to serve as an important water source for arid soil biocrusts, which require water threshold of 0.05 (for lichens) and 0.1 mm (for cyanobacteria) for growth. Such values are commonly reported in the literature. Moreover, values of >0.45 mm/d (considered as the practical theoretical threshold for dew) are also reported. Following an analysis of limited (29 days) dewy mornings, it was recently reported that dew is incapable of forming on the soil surface. Being of limited scope, we therefore analyse days that yielded the highest amounts of NRW during 2 years (2021–2023) of measurements (22 days with NRW ≥0.15 mm). We conducted measurements at 1 m above ground, cobbles, rocks, and the soil surface, and compared them to the cloth‐plate method. Additionally, periodical temperature measurements were conducted, and the dewpoint temperature (Td) was calculated. Our findings indicate that (a) dew yield never surpassed 0.4 mm, (b) while the water threshold amounts were reached on the rocks and especially on the cobbles, these thresholds were seldom reached on soil (a single morning with 0.1 mm and 3 days with ≥0.05 mm), (c) in comparison to air temperatures at 0.05 m and especially at 1 m‐height above ground, surface nocturnal soil temperatures were 2–3°C warmer, thus eliminating possible vapour condensation. Our data cast doubt on values of >0.45 mm reported from various deserts. Additionally, while supporting the view that NRW may provide water for the growth of rock‐dwelling lichens, NRW in the Negev does not provide the soil biocrusts with sufficient water for growth. [ABSTRACT FROM AUTHOR]

Given 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. [ABSTRACT FROM AUTHOR]

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. Summary Statement: This study demonstrates that foliar water uptake (FWU) through hydathodes, previously suspected but unconfirmed, is indeed operational in most Crassula species. This phenomenon occurs across different habitats and highlights the ecophysiological relevance of atmospheric humidity for these plants. [ABSTRACT FROM AUTHOR]

Water infiltration into fractures is ubiquitous in crustal rocks. However, little is known about how such a progressive wetting process affects fracture stiffness and seismic wave propagation, which are highly relevant for characterizing fracture systems in situ. We study the acousto‐mechanical behavior of a free‐standing fractured granite subjected to gradual water infiltration with a downward‐moving wetting front over 12 days. We observe significant differences (i.e., by an order of magnitude) in wave amplitudes across the fractured granite compared to an intact granite, with both cases showing a strong correlation between wave amplitudes and wetting front movement. Effects of water infiltration into the fracture and surrounding matrix on seismic attenuation are captured by a numerical model with parameters constrained by experimental data. Back‐calculated fracture stiffness decreases exponentially with the wetting front migration along the fracture. We propose that moisture‐induced matrix expansion around the fracture increases asperity mismatch, leading to reduced fracture stiffness. Plain Language Summary: In the shallow layers of the Earth, hydrological cycles such as snowmelt, fog, dew, and rain have been shown to change the moisture content of crustal rocks, which can alter the elastic properties of natural fractures and affect the propagation of seismic waves. Understanding how seismic waves propagate in the near‐surface environment is crucial for the assessment of earthquake hazards and the characterization of geologic heterogeneities. In this work, we perform well‐controlled laboratory experiments to study the acousto‐mechanical behavior of a single fracture in granitic rock subjected to progressive wetting over 12 days. We report that the fracture stiffness decreases exponentially as the wetting front advances along the fracture. Our research sheds light on an important question in fracture characterization: how elastic waves propagate across a fracture undergoing moisture‐induced expansion. Key Points: A laboratory study establishes a relationship among water imbibition, seismic attenuation, and stiffness evolution in a wetted fractureWave amplitudes across a fracture correlate strongly with the wetting front movement of infiltrated water within the fractureFracture stiffness exponentially decreases with the advance of the wetting front along the fracture [ABSTRACT FROM AUTHOR]

The 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. [ABSTRACT FROM AUTHOR]

Nanostructured materials have enabled new ways of controlling the light–matter interaction, opening new routes for exciting applications, in display technologies and colorimetric sensing, among others. In particular, metallic nanoparticles permit the production of color structures out of colorless materials. These plasmonic structural colors are sensitive to the environment and thus offer an interesting platform for sensing. Here, a self‐assembly of aluminum nanoparticles in close proximity of a mirror is spaced by an ultrathin poly(N‐isopropylacrylamide) (PNIPAM) layer. Hybridizing the plasmonic system with the active polymer layer, a thermoresponsive gap‐plasmon architecture is formed that transduces changes in the temperature and relative humidity of the environment into color changes. By harnessing the environmentally induced structural changes of PNIPAM, it was estimated from the finite difference time domain simulation that the resonance can be tuned 7 nm per every 1 nm change in thickness, resulting in color variation. Importantly, these fully reversible changes can be used for reusable powerless humidity and temperature colorimetric sensing. Crucially if condensation on the structure happens, the polymer layer is deformed beyond recovery and the colors are washed away. We leverage this effect to produce tamper‐proof dew labels that a straightforward smartphone app can read by taking a picture. [ABSTRACT FROM AUTHOR]

Soil biocrusts abound in deserts, but yet little agreement exists regarding their water sources. Most researchers regard non‐rainfall water (NRW), particularly dew as an important water source for soil biocrusts, but nevertheless, evidence from the Negev suggests that following the nocturnal soil heat efflux, NRW is drastically reduced. The possible contribution of NRW to 3‐ to 5‐mm‐tall lichens, which are less impacted by the warm nocturnal surface temperatures, poses an additional challenge. For this end, NRW obtained by cloths attached to the soil surface and cloths located at a 5‐mm height above ground were measured, accompanied by periodic temperature measurements. As for the cyanobacteria and the 1‐mm‐tall lichens, NRW did not reach the necessary threshold required for the performance of net photosynthesis by cyanobacterial (0.1 mm) or chlorolichens (0.05 mm) but was occasionally reached at 5‐mm height above ground. Nevertheless, when the average amount obtained at 1‐mm intervals (mimicking the length of the lichen thallus) along the 5‐mm height was calculated, it either fell below the necessary threshold or was too low during daytime to compensate for the carbon loss during nighttime respiration. The apparent incapability of NRW to provide sufficient water to sustain the 3‐ to 5‐mm‐tall lichens in the Negev Highlands is supported by the confinement of these lichens to north‐facing rock terraces (ledges), where they may benefit from additional water through runoff. One may therefore conclude that NRW may not be regarded as a meaningful water source for the Negev biocrusts, whether composed of cyanobacteria or of 1‐ to 5‐mm‐tall lichens. [ABSTRACT FROM AUTHOR]

Dew is one of the important moisture sources in many arid and semiarid regions. The knowledge of moisture origin of dew under various climatic conditions is still lacking. Isotopic variations can preserve information about moisture origin and formation mechanisms. Therefore, the isotopic compositions of dew and precipitation (δ2H, δ18O, δ17O, d‐excess, lc‐excess and 17O‐excess) were investigated at three sites with different climatic conditions (i.e., Gobabeb with extremely dry climate, Nice with Mediterranean climate and Indianapolis with humid continental climate). The results showed that there were three types of dew at Gobabeb: advective dew, groundwater‐derived dew, and shallow soil water‐derived dew, accounting for 27.3%, 45.4% and 27.3% of the dew events, respectively. The ultimate moisture sources of advective dew and the other two types of dew at Gobabeb were from the South Atlantic Ocean and a mixture of the Indian and South Atlantic Oceans, respectively. Dew in Nice included ocean‐derived dew from the North Atlantic Ocean with local evapotranspiration replenishment, and local‐derived dew, mainly from the continental Europe and Mediterranean Sea, accounting for 39.1% and 60.9% of the dew events, respectively. All the Indianapolis dew were likely local‐derived dew. Based on the moisture origins, the future dew trends were speculated under global warming. Dew frequencies at Gobabeb and Indianapolis under future climates are uncertain due to the concurrent increases in atmospheric water vapour and temperature. The local‐derived dew in Nice would likely decrease due to the decreasing precipitation and increasing drought, and the ocean‐derived dew under future climates is uncertain. This study provides a practical method to distinguish dew moisture sources, and such information is useful for future prediction of dew trends under climate change. [ABSTRACT FROM AUTHOR]

Many organisms use functional surfaces to collect water from the atmosphere. Salsola ferganica Drob. is one of the most abundant plants in desert regions and thrives in extreme environments with multiple but limited water resources, including dew and fog; however, its mechanisms of water harvesting remain unclear. We investigated trichome structural characteristics and their influence on the surface wettability of S. ferganica leaves using a variety of approaches (scanning electron microscopy, optical microscopy, immunolabelling staining, x‐ray diffractometry, and infrared spectroscopy). Microstructural observations revealed that the trichomes of S. ferganica presented a curved upper part, the 'spindle node'‐like structure in the middle, and the micro‐grooves structure in between; such unique structures may aid in capturing moisture from the air. The physicochemical characteristics of the trichome surface, including hydrophobic functional groups, hydrophilic pectins, and low crystallinity, may enhance the adhesion of water drops to trichomes. Furthermore, we discovered that the piliferous S. ferganica leaves were more effective in retaining water than the glabrous S. aralocaspica leaves, and the dense trichome layer exhibited a significantly unwettable surface (high contact angle with droplets), whereas the individual trichomes retained water effectively (more so under drought conditions). The combination of these two properties is consistent with the 'rose petal effect', which describes rough surfaces that are hydrophobic but exhibit high adhesion with water. These factors suggest that the evolutionary optimisation of water acquisition by coupling relevant microstructures with the physicochemical properties of trichomes enables S. ferganica to survive harsh conditions in the seedling stage. [ABSTRACT FROM AUTHOR]

Occult precipitation events (fog, dew and light rain) can alter plant water and nutritional status, both directly through the aerial uptake of surface water and nutrients, and indirectly via redistribution of atmospheric resources to the soil. However, current frameworks that explain niche segregation, species interactions and coexistence still consider that ground‐rooted plants obtain resources almost exclusively via root absorption from soil.Here, we expand the plant hydrological niches model to incorporate both soil and atmospheric resource‐axes, thus providing a more complete picture of how ground‐rooted terrestrial plants obtain, remobilise, share and compete for water and soluble nutrients.First, we describe how plants with different water acquisition strategies access directly or indirectly atmospheric resources. Then, we discuss how the use of such resources may promote spatiotemporal niche segregation, contributing to shape species distribution and abundance within plant communities. We illustrate this argument with examples from arid, mesic and wet vegetation types. Finally, we examine how climate and land‐use changes may influence plant hydrological niches, potentially altering community structure.Synthesis. Understanding how available atmospheric resources influences niche segregation in plant communities is a crucial step towards better predictions of species responses (e.g. changes in distribution, abundance and interactions) to climate change. [ABSTRACT FROM AUTHOR]

Preserved eggs have been reported to possess anti‐inflammatory and antioxidant bioactivities, which are enhanced after protein glycation. However, it is still unknown which proteins are glycated during pickling process of preserved eggs and whether the glycated proteins are related to the bioactivity of preserved eggs. In this study, UPLC‐ESI‐MS/MS was used to identify glycation of proteins in preserved egg white (PEW) and duck egg white (DEW). Altogether, 142 sites on 53 glycated proteins were detected in PEW while 9 sites on 2 glycated proteins were found in DEW. Bioinformatic analysis suggested that the glycation of PEW proteins (e.g. Ovalbumin, Ovotransferrin, Albumin) were supposed to be connected with allergenicity reduction, and the enhancement of antibacterial and antioxidant bioactivities. These findings provide some indications for the future studies on the detailed bioactivities of glycated proteins in PEW, and pave the way for applied research on glycation and the development of functional foods. [ABSTRACT FROM AUTHOR]

Litter decomposition plays a central role in carbon cycling in terrestrial ecosystems worldwide. In drylands, which cover 40% of the Earth's land surface, photodegradation and biotic decomposition driven by non‐rainfall moisture are important mechanisms of litter decay, though studies have only recently begun examining interactions between these two processes. We describe a novel priming mechanism in which photodegradation and biotic decay of the cuticle of plant litter increase litter absorption of non‐rainfall moisture (fog, dew and water vapor), supporting greater microbial decomposition.We used several field experiments in a coastal fog desert and a series of in situ observations to demonstrate a relationship between solar radiation, cuticle integrity, water absorption rates and mass loss.Experimentally attenuating solar radiation for 36 months slowed mass loss, reduced cuticle degradation and decreased litter moisture uptake relative to litter under ambient sunlight controls. In a separate field experiment, removing the cuticle of recently senesced grass tillers increased mass loss fourfold over 6 months relative to controls. Tillers with degraded cuticles also absorbed 3.8 times more water following an overnight dew event than did those with intact cuticles. Finally, fungal growth was consistently greater on the sun‐facing side of in situ tillers than on the shaded side, coincident with greater cuticle degradation.We present a conceptual model where the cuticle of plant litter acts as a water‐resistant barrier that is first degraded by solar radiation and surficial microbes, increasing litter's ability to absorb enough water during non‐rainfall moisture events to support substantial biotic decomposition inside the tissue. Considering how photodegradation and non‐rainfall moisture are both substantial drivers of litter decomposition in drylands, understanding how they interact under realistic field conditions will help us better predict how these systems are responding to changing climate regimes. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Long‐term field campaigns in the Negev observed wet–dry cycles (WDCs) following rain events, principally on sand. Aiming to assess the relevant mechanism (whether dewfall, water capillarity or distillation derived by temperature‐induced vapor flux [TIVF] which stems from the soil), a set of outdoor experiments was conducted on sand and loess. They included nonrainfall water (NRW) and temperature measurements during the rainless dry seasons (summer, fall) and during the winter, which was divided to a wet (following rain) and dry periods. Dew measurements were conducted on cloths, whether directly attached to the soil or located at 0.5 cm above ground, aiming to eliminate capillarity and assessing the possible contribution of dewfall and TIVF‐induced distillation. Our findings show that (a) WDCs were only observed following rainstorms, particularly on sand, (b) WDCs could not have been explained by capillarity (they continued at the presence of an air gap), (c) significantly lower minimum surface temperatures (averaging 0.8°C) characterized the sand, which following rainstorms resulted in higher NRW due to TIVF, that is, visibly noted WDCs. With sand being characterized by a lush cover of biocrusts in the Negev dunefields, while being largely absent from the loessial playas scattered within the dunefield, it is suggested that WDCs may play an important role in the establishment and growth of biocrusts over sand dunes of the Negev and possibly in other arid dunes. [ABSTRACT FROM AUTHOR]

The Brazilian Cerrado is a global biodiversity hotspot with notoriously high rates of native vegetation suppression and wildfires over the past three decades. As a result, climate change can already be detected at both local and regional scales. In this study, we used three different approaches based on independent datasets to investigate possible changes in the daytime and nighttime temperature and air humidity between the peak of the dry season and the beginning of the rainy season in the Brazilian Cerrado. Additionally, we evaluated the tendency of dew point depression, considering it as a proxy to assess impacts on biodiversity. Monthly increases of 2.2−4.0℃ in the maximum temperatures and 2.4−2.8℃ in the minimum temperatures between 1961 and 2019 were recorded, supported by all analyzed datasets which included direct observations, remote sensing, and modeling data. The warming raised the vapor pressure deficit, and although we recorded an upward trend in absolute humidity, relative humidity has reduced by ~15%. If these tendencies are maintained, gradual air warming will make nightly cooling insufficient to reach the dew point in the early hours of the night. Therefore, it will progressively reduce both the amount and duration of nocturnal dewfall, which is the main source of water for numerous plants and animal species of the Brazilian Cerrado during the dry season. Through several examples, we hypothesize that these climate changes can have a high impact on biodiversity and potentially cause ecosystems to collapse. We emphasize that the effects of temperature and humidity on Cerrado ecosystems cannot be neglected and should be further explored from a land use perspective. [ABSTRACT FROM AUTHOR]

Adoption of dicamba tolerant soybeans [Glycine max (L.) Merr.] accompanied by postemergence applications of dicamba resulted in off‐target movement and damage to nearby crops. The underlying cause, in some cases, has been attributed to weather‐related phenomena such as temperature inversions, which are often accompanied by the formation of dew. The objective of this controlled study was to determine if the formation of simulated dew on soybean leaves treated with dicamba led to increased short‐term dicamba volatility. Over a 48‐h period after the application of dicamba, dicamba volatility concentrations quantified in air samples increased by 20% when soybeans were exposed to simulated dew for 3 h compared with soybeans that were not exposed to dew. Concentrations of volatilized dicamba were elevated in the first (0–24 h) and second (24–48 h) 24‐h period after initiating collection of air samples. Dew may alter the stability of dicamba, ultimately contributing to increased off‐target movement. Core Ideas: Simulated dew increases dicamba volatility from soybean leaves.Greater dicamba volatility persisted up to 48 h when soybeans were exposed to dew.Within temperature inversions, dew is a key factor leading to increased dicamba volatility. [ABSTRACT FROM AUTHOR]

Investigating plant morphological traits can provide insights into plant drought tolerance. To date, many papers have focused on plant hydraulic responses to drought during dehydration, but atmospheric water absorption by trichomes to mitigate drought stress by influencing leaf hydraulics in plant species that inhabit arid environments has been largely ignored. The experiment in this study was designed to assess how dew absorbed by leaf trichomes helps Caragana korshinskii withstand drought. The results showed that under a drought stress and dew (DS & D) treatment, C. korshinskii displayed a strong capacity to absorb dew with trichomes; exhibited slow decreases in leaf water potential (Ψleaf), leaf hydraulic conductivity (Kleaf), and gas exchange; experienced 50% Kleaf and gas exchange losses at lower relative soil water content levels than plants treated with drought stress and no dew (DS & ND); and experienced 50% Kleaf loss (Kleaf P50) at similar Ψleaf levels as DS & ND plants. Its congener C. sinica, which does not have leaf trichomes, displayed little ability to absorb dew under drought stress and did not show any remarkable improvement in the above parameters under the DS & D treatment. Our results indicated that leaf trichomes are important epidermal dew-uptake structures that assist in partially sustaining the leaf hydraulic assimilation system, mitigate the adverse effects of drought stress and contribute to the distribution of C. korshinskii in arid environments. [ABSTRACT FROM AUTHOR]

Long‐term (1961–2010) observations of dew data collected at 597 stations over China show that dew frequency decreased by 5.2 days per decade due primarily to near‐surface warming and associated decreases in relative humidity (RH). Moreover, the percentage decreasing rate of dew frequency in arid regions (precipitation PR <400 mm yr−1) are larger than that in humid regions (PR ≥800 mm yr−1). Compared with the 1960s, the mean dew frequency in the 2000s decreased by 28%, 40%, 50% in humid, semihumid (400 ≤ PR < 800 mm yr−1), and arid regions, respectively. Surface warming is larger in arid regions in northwestern China than its humid and semihumid regions during recent global warming, which leads to larger decreases in surface RH and makes dew events less likely. Since dew contributes significantly to surface water balance in arid regions, the large decreases in dew frequency may contribute to "the drier getting drier" response to global warming over arid regions. Plain Language Summary: Here we show, by analyzing 50 years (1961–2010) of data collected at 597 stations in China, that dew occurrence in China exhibits a clear decreasing trend, and the decreasing rate of dew frequency in arid regions is higher than that in semihumid and humid regions. Compared with the 1960s, the mean dew frequency in the 2000s decreased by 28%, 40%, 50% in the humid, semihumid, and arid regions of China, respectively. Further analysis reveals that the decreased dew frequency is caused primarily by near‐surface warming and drying. Large decreases in surface relative humidity in arid regions associated with large warming makes dew events less likely. This could make the region drier as dew is a significant water source in arid regions. Key Points: Near‐surface warming has induced significantly decline of dew occurrence in ChinaThe decreasing rate of dew frequency in arid regions is higher than that in semihumid and humid regionsThis finding sheds new understanding of the issue of "drier getting drier" for arid regions under global warming [ABSTRACT FROM AUTHOR]

Manipulative experiments typically show a decrease in dryland biocrust cover and altered species composition under climate change. Biocrust‐forming lichens, such as the globally distributed Diploschistes diacapsis, are particularly affected and show a decrease in cover with simulated climate change. However, the underlying mechanisms are not fully understood, and long‐term interacting effects of different drivers are largely unknown due to the short‐term nature of the experimental studies conducted so far.We addressed this gap and successfully parameterised a process‐based model for D. diacapsis to quantify how changing atmospheric CO2, temperature, rainfall amount and relative humidity affect its photosynthetic activity and cover. We also mimicked a long‐term manipulative climate change experiment to understand the mechanisms underlying observed patterns in the field.The model reproduced observed experimental findings: warming reduced lichen cover, whereas less rainfall had no effect on lichen performance. This warming effect was caused by the associated decrease in relative humidity and non‐rainfall water inputs, which are major water sources for biocrust‐forming lichens. Warming alone, however, increased cover because higher temperatures promoted photosynthesis during early morning hours with high lichen activity. When combined, climate variables showed non‐additive effects on lichen cover, and effects of increased CO2 levelled off with decreasing levels of relative humidity.Synthesis. Our results show that a decrease in relative humidity, rather than an increase in temperature, may be the key factor for the survival of the lichen D. diacapsis under climate change and that effects of increased CO2 levels might be offset by a reduction in non‐rainfall water inputs in the future. Because of a global trend towards warmer and drier air and the widespread global distribution of D. diacapsis, this will affect lichen‐dominated dryland biocrust communities and their role in regulating ecosystem functions worldwide. [ABSTRACT FROM AUTHOR]

As an important source of non‐rainfall input of land–surface liquid water, dew has considerable ecological and hydrological significance in desert ecosystems. Dew moisture regime is commonly used for characterizing available dew. It discloses not only the contributions of dew to plants, small animals, and biological crusts but also the mechanism by which desert organisms adapt to extreme climates. By reviewing the existing researches on dew moisture regimes in desert ecosystems, this study reveals the variations in the amount and duration of dew, as well as its influencing factors at site‐, catchment‐, and regional scales, based on the radiation cooling theory and the physical mechanisms of dew formation. Furthermore, it compares the differences in dew moisture between various sites and catchments, illustrates the trends in daily and annual dew moisture in various deserts, and identifies the existing problems of researches on dew moisture regimes amid climate change. The findings of this study enhance preliminary knowledge on the reasonable utilization of dew water, worldwide. This article is categorized under:Science of Water > Hydrological ProcessesWater and Life > Nature of Freshwater Ecosystems [ABSTRACT FROM AUTHOR]

Summary: To extend the reach of cloud computing, the concept of edge computing and dew computing is introduced to execute various Internet of things (IoT) application with minimized delay in real time. The requested tasks are allocated computing resources that best suits their purpose. In this work, a novel hybrid hierarchical dew based edge to cloud architecture is developed. The objective of the study is to provide a detailed analysis and validation of real‐time scheduling of IoT application in this hybrid hierarchical ecosystem. The problem of optimally mapping requested tasks to the computing layers is mathematically formulated based on several quality of service factors and solved using the proposed hybrid adaptive metaheuristic algorithm. This is a combination of learning‐based adaptive particle swarm optimization and genetic algorithm. The exploitative and exploratory feature of the proposed algorithm helps in achieving better global optima compared with other existing metaheuristic algorithms. [ABSTRACT FROM AUTHOR]

Intense sub‐daily summer rainfall is linked to flooding impacts in the United Kingdom. Characterizing the atmospheric conditions prior to the rainfall event can improve understanding of the large‐scale mechanisms involved. The most intense sub‐daily rainfall intensity data generated from rain gauge records across the United Kingdom over the period 1979–2014 are combined with fields from the ERA Interim reanalysis to characterize atmospheric conditions prior to heavy rainfall events. The 200 most intense 3‐hourly events for six UK regions are associated with negative anomalies in sea level pressure (<−2 hPa) and 200 hPa geopotential height (<−60 m) to the west or south west of the United Kingdom 1 day earlier, with above average moisture, evaporation and dew point temperature over North West Europe. Atmospheric precursors are more intense but less coherent between regions for composites formed of the 25 heaviest rainfall events but all display substantial moisture transport from the south or south east prior to their occurrence. Composites for the heaviest events are characterized by a tripole geopotential anomaly pattern across the North Atlantic. Above average geopotential height and dew point temperature over Newfoundland and below average geopotential height but elevated evaporation in the North Atlantic are found to be weakly associated with an increased chance of the most intense sub‐daily rainfall events 5–9 days later. [ABSTRACT FROM AUTHOR]

Snow cover ablation in the Great Lakes basin is a common and hydrologically important process during the cold season, contributing to a majority of the basin's runoff, and less frequent, extreme ablation events are highly impactful due to an increased flooding risk and warrant specific investigation. A brief climatology of extreme ablation events is presented, where extreme is considered within the top 5% of the distribution. Using synoptic classification techniques, individual weather patterns associated with extreme snow ablation in the Great Lakes basin are isolated. A single pattern deemed the most influential in generating extreme ablation events, southerly flow‐1, is examined in detail, and three case studies are presented to determine the meteorological conditions and surface energy fluxes responsible for ablation. Over 75% of extreme events are associated with southerly flow patterns that predominantly ablate snow with sensible heat fluxes, while rain‐on‐snow patterns induce the remaining extreme events from 1980–2009. Type southerly flow‐1 is responsible for 45% of the extreme events and is characterized by strong southerly advection of warm air into the basin, where sensible heat fluxes of 45–125 Wm−2 are responsible for the majority of energy transfer into the snowpack. When compared with an average ablation event, an extreme ablation event for southerly flow‐1 exhibits air temperatures, dew point temperatures, and wind speeds that are 3.8°C, 3.0°C, and 1.2 ms−1 warmer and faster than an average event, indicating a greater potential for larger ablation. [ABSTRACT FROM AUTHOR]

The likelihood of dew to provide water to cyanobacteria (CB) and crustose lichens (CL) on soil is a matter of great controversy. Although vapour condensation takes place on cobbles of the Negev Highlands, facilitating lush cover of CL, controversy exists regarding the possible contribution of dew to CB and CL inhabiting the loessial soil of the Negev Highlands. To evaluate this matter, temperature, and measurements of the nonrainfall water (NRW) were conducted during the dewy season (August–November 2019). They included periodical NRW measurements using cloths attached to the (a) soil surface, (b) on top of 10 × 10 × 5‐ to 6‐cm cobbles, and (c) on 10 × 10 × 0.2‐cm glass plates (the cloth‐plate method, CPM). Additionally, temperature measurements took place at the soil and the cobble surfaces and in the air at 10‐cm height above ground. Air temperature and the relative humidity measured by an adjacent meteorological station facilitated the calculation of the dew‐point temperature (Td). Taking the CPM as reference, 24 mornings with NRW ≥0.03 mm (the threshold of lichen metabolism) were recorded. Vapour condensation, that is, NRW ≥0.1 mm were recorded during 16 mornings on the cobbles (with a maximum of 0.21 mm) but never on the soil, where maximum NRW reached only 0.023 mm. Surface temperature never reached Td. We therefore conclude that unlike lithic lichens that inhabit bedrocks and cobbles in the Negev Highlands, dew cannot be regarded as a meaningful direct source of water for CB or CL biocrusts on soil. [ABSTRACT FROM AUTHOR]

A total of 32 rainfall events spanning the period from 2012 to 2014 over the urban Indian city of Bangalore were simulated using the Weather Research and Forecast (WRF) model. Model simulations were carried out with a four‐nested domain initialized with Global Forecast System (GFS) data and the forecast was generated on an hourly basis. The forecasted rainfall at hobli level (Bangalore has 34 hobli divisions with an area of each hobli of the order of about 10 km2) was evaluated in terms of its intensity and pattern of spatial distribution by comparing it with corresponding rain‐gauge observations. Also, the rainfall forecast skill of the model was evaluated statistically by computing root mean square error, bias and mean absolute error. Thermodynamic variables such as equivalent potential temperature, convective available potential energy (CAPE), convective inhibition (CIN), K index (KI), lifted index (LI) and total totals index (TTI) were also derived from the simulated model parameters for all the events and then verified against corresponding observations. The results showed that the WRF model could simulate the rainfall events and associated thermodynamic features qualitatively; however, there were few hoblis where the relative errors in the forecast were > 100%. The forecast errors were relatively lower for cases during the southwest monsoon season compared with other seasons. It was found that the model underestimated thermodynamic indices such as CAPE, dew point depression and the simulated LI were positive; these were indicative of the model's limitation in simulating intense convection and a possible reason for underpredicted rainfall simulations. [ABSTRACT FROM AUTHOR]

High‐frequency stable isotope data are useful for validating atmospheric moisture circulation models and provide improved understanding of the mechanisms controlling isotopic compositions in tropical rainfall. Here, we present a near‐continuous 6‐month record of O‐ and H‐isotope compositions in both water vapour and daily rainfall from Northeast Australia measured by laser spectroscopy. The data set spans both wet and dry seasons to help address a significant data and knowledge gap in the southern hemisphere tropics. We interpret the isotopic records for water vapour and rainfall in the context of contemporaneous meteorological observations. Surface air moisture provided near‐continuous tracking of the links between isotopic variations and meteorological events on local to regional spatial scales. Power spectrum analysis of the isotopic variation showed a range of significant periodicities, from hourly to monthly scales, and cross‐wavelet analysis identified significant regions of common power for hourly averaged water vapour isotopic composition and relative humidity, wind direction, and solar radiation. Relative humidity had the greatest subdiurnal influence on isotopic composition. On longer timescales (weeks to months), isotope variability was strongly correlated with both wind direction and relative humidity. The high‐frequency records showed diurnal isotopic variations in O‐ and H‐isotope compositions due to local dew formation and, for deuterium excess, as a result of evapotranspiration. Several significant negative isotope anomalies on a daily scale were associated with the activity of regional mesoscale convective systems and the occurrence of two tropical cyclones. Calculated air parcel back trajectories identified the predominant moisture transport paths from the Southwest Pacific Ocean, whereas moisture transport from northerly directions occurred mainly during the wet season monsoonal airflow. Water vapour isotope compositions reflected the same meteorological events as recorded in rainfall isotopes but provided much more detailed and continuous information on atmospheric moisture cycling than the intermittent isotopic record provided by rainfall. Improved global coverage of stable isotope data for atmospheric water vapour is likely to improve simulations of future changes to climate drivers of the hydrological cycle. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Xu et al. (2021), 231: 122–136. [ABSTRACT FROM AUTHOR]

Foliar uptake of dew is likely an important mechanism of water acquisition for plants from tropical dry environments. However, there is still limited experimental evidence describing the anatomical pathways involved in this process and the effects of this water subsidy on the maintenance of gas exchange and leaf lifespan of species from seasonally dry tropical vegetation such as the Brazilian caatinga.We performed scanning electron, bright‐field and confocal microscopic analyses and used apoplastic tracers to examine the foliar water uptake (FWU) routes in four woody species with different foliar phenology and widely distributed in the caatinga. Leaves of plants subjected to water stress were exposed to dew simulation to evaluate the effects of the FWU on leaf water potentials, gas exchange and leaf lifespan.All species absorbed water through their leaf cuticles and/or peltate trichomes but FWU capacity differed among species. Leaf wetting by dew increased leaf lifespan duration up to 36 days compared to plants in the drought treatment. A positive effect on leaf gas exchange and new leaf production was only observed in the anisohydric and evergreen species.We showed that leaf wetting by dew is relevant for the physiology and leaf lifespan of plants from seasonally dry tropical vegetation, especially for evergreen species. [ABSTRACT FROM AUTHOR]

The environment has a strong influence on the abundance and distribution of plant pathogenic organisms and plays a major role in plant disease. Climatological factors may also alter the dynamics of the interactions between plant pathogens and their hosts. Nothophaeocryptopus (=Phaeocryptopus) gaeumannii, the causal agent of Swiss needle cast (SNC) of Douglas‐fir, is endemic to western North America where it exists as two sympatric, reproductively isolated lineages. The abundance of this fungus and the severity of SNC are strongly influenced by climate. We used statistical and population genetic analyses to examine relationships between environment, pathogen population structure, and SNC severity. Although N. gaeumannii Lineage 2 in western Oregon and Washington was most abundant where SNC symptoms were most severe, we did not detect a significant relationship between Lineage 2 and disease severity. Warmer winter temperatures were inversely correlated with foliage retention (AFR) and positively correlated with the relative abundance of Lineage 2 (PL2). However when distance inland, which was strongly correlated with both AFR and PL2, was included in the model, there was no significant relationship between Lineage 2 and AFR. Spring/early summer dew point temperatures also were positively associated with total N. gaeumannii abundance (colonization index (CI)) and inversely correlated with AFR. Warmer summer mean temperatures were associated with lower CI and higher AFR. Our results suggest that the two lineages have overlapping environmental optima, but slightly different tolerance ranges. Lineage 2 was absent from more inland sites where winters are colder and summers are warm and dry, while Lineage 1 occurred at most sites across an environmental gradient suggesting broader environmental tolerance. These relationships suggest that climate influences the abundance and distribution of this ecologically important plant pathogen and may have played a role in the evolutionary divergence of these two cryptic fungal lineages. [ABSTRACT FROM AUTHOR]

The Clausius‐Clapeyron (CC) relation expresses the exponential increase in the moisture‐holding capacity of air of approximately 7%/°C. Earlier studies show that extreme hourly precipitation increases with daily mean temperature, consistent with the CC relation. Recent studies at specific locations found that for temperatures higher than around 12 °C, hourly precipitation extremes scale at rates higher than the CC scaling, a phenomenon that is often referred to as "super‐CC scaling." These scalings are typically estimated by collecting rainfall data in temperature bins, followed by a linear fit or a visual inspection of the precipitation quantiles in each bin. In this study, a piecewise linear quantile regression model is presented for a more flexible, and robust estimation of the scaling parameters, and their associated uncertainties. Moreover, we use associated information criteria to prove statistically whether or not a pronounced super‐CC scaling exists. The techniques were tested on stochastically simulated data and, when applied to hourly station data across Western Europe and Scandinavia, revealed large uncertainties in the scaling rates. Finally, goodness‐of‐fit measures indicated that the dew point temperature is a better scaling predictor than temperature. Key Points: Piecewise linear quantile regression is used to quantify the transition from CC scaling to super‐CC scalingLarge uncertainties exist for the scaling rates and change points of observed precipitation extremesGoodness‐of‐fit measures indicate that the dew point temperature is a better scaling predictor than temperature [ABSTRACT FROM AUTHOR]

The absorption of atmospheric water directly into leaves enables plants to alleviate the water stress caused by low soil moisture, hydraulic resistance in the xylem and the effect of gravity on the water column, while enabling plants to scavenge small inputs of water from leaf‐wetting events. By increasing the availability of water, and supplying it from the top of the canopy (in a direction facilitated by gravity), foliar uptake (FU) may be a significant process in determining how forests interact with climate, and could alter our interpretation of current metrics for hydraulic stress and sensitivity. FU has not been reported for lowland tropical rainforests; we test whether FU occurs in six common Amazonian tree genera in lowland Amazônia, and make a first estimation of its contribution to canopy–atmosphere water exchange. We demonstrate that FU occurs in all six genera and that dew‐derived water may therefore be used to "pay" for some morning transpiration in the dry season. Using meteorological and canopy wetness data, coupled with empirically derived estimates of leaf conductance to FU (kfu), we estimate that the contribution by FU to annual transpiration at this site has a median value of 8.2% (103 mm/year) and an interquartile range of 3.4%–15.3%, with the biggest sources of uncertainty being kfu and the proportion of time the canopy is wet. Our results indicate that FU is likely to be a common strategy and may have significant implications for the Amazon carbon budget. The process of foliar water uptake may also have a profound impact on the drought tolerance of individual Amazonian trees and tree species, and on the cycling of water and carbon, regionally and globally. [ABSTRACT FROM AUTHOR]

The first in the next‐generation series of the US Geostationary Operational Environmental Satellites system (GOES), GOES‐16, is providing improved quality satellite imagery of atmospheric phenomena and land features over the Americas and the Atlantic Ocean, benefitting scientists and operational meteorologists. A frontal passage separating distinct air masses for a typical warm season case over the Upper Midwest on August 30, 2017, is examined in a discussion on the value of GOES‐16 infrared window band imagery. The "split window" difference between the 10.3 and 12.3 μm long wave infrared bands, a traditional approach to characterizing visually low‐level water vapour in cloud‐free scenes, is compared with the 3.9 μm short wave infrared window band for identifying two distinct air masses. Surface station temperatures and dew points confirm modest moisture pooling ahead of the southward‐moving front. These window bands are not new to the geostationary orbit, but with GOES‐16, they are available at higher bit depths and at better spatial, spectral and temporal resolutions. This makes identifying and analysing fronts and air masses more apparent compared with legacy imagery, particularly during the day if properly enhanced. While a hindrance to quantitative approaches, solar contamination in the 3.9 μm band can be beneficial to analysts performing this task visually. [ABSTRACT FROM AUTHOR]

High‐resolution gridded climate data products are crucial to research and practical applications in climatology, hydrology, ecology, agriculture, and public health. Previous works to produce multiple data sets were limited by the availability of input data as well as computational techniques. With advances in machine learning and the availability of several daily satellite data sets providing unprecedented information at 1 km or higher spatial resolutions, it is now possible to improve upon earlier data sets in terms of representing spatial variability. We developed the NEX (NASA Earth Exchange) Gridded Daily Meteorology (NEX‐GDM) model, which can estimate the spatial pattern of regional surface climate variables by aggregating several dozen two‐dimensional data sets and ground weather station data. NEX‐GDM does not require physical assumptions and can easily extend spatially and temporally. NEX‐GDM employs the random forest algorithm for estimation, which allows us to find the best estimate from the spatially continuous data sets. We used the NEX‐GDM model to produce historical 1‐km daily spatial data for the conterminous United States from 1979 to 2017, including precipitation, minimum temperature, maximum temperature, dew point temperature, wind speed, and solar radiation. In this study, NEX‐GDM ingested a total of 30 spatial variables from 13 different data sets, including satellite, reanalysis, radar, and topography data. Generally, the spatial patterns of precipitation and temperature produced were similar to previous data sets with the exception of mountain regions in the western United States. The analyses for each spatially continuous data set show that satellite and reanalysis led to better estimates and that the incorporation of satellite data allowed NEX‐GDM to capture the spatial patterns associated with urban heat island effects. The NEX‐GDM data is available to the community through the NEX data portal. [ABSTRACT FROM AUTHOR]

Unmanned aerial systems (UASs) are becoming valuable environmental data collection tools, allowing the user freedom to attach sensors and to launch at a moment's notice while also collecting spatially precise data all at a relatively low cost (Simic Milas et al., [13]; Nowak, Dziób, & Bogawski, [15]; Dunbabin & Marques, [5]; Manfreda et al., [12]). Before each flight, the sensor was preset to begin data collection 5 min before the UAV was launched and then record relative humidity and air temperature data every 5 s. While the UAV was taking off, the sensors and monofilament were held taut and slowly released as the UAV rose to prevent the monofilament from being tangled in the propellers. Our system, a UAV coupled with an atmospheric sensor, is affordable ($935 to $1635 strongly depending on UAV cost), requires little set-up, and produces high resolution data sets in space and time. [Extracted from the article]

Fog and dew are often viewed as economic nuisances causing significant financial losses in the transportation industry and agricultural sector. However, they are also critical components of the hydrological cycle, especially in water scarce environments. Water scarcity is one of the major threats to mankind in the 21st century, and this can be due to development pressures, pollution, and/or expanding populations. In water scarce environments, fog and dew represent potentially exploitable ancillary water resources that could ameliorate the water scarce situation, if efficiently harvested. However, two important issues are often overlooked in relation to fog and dew harvesting and potability. First, current fog and dew harvesting technologies are low yielding with great potential for improvements. Second and more importantly, the potability of these water resources is often based on simple analyses that often omit trace metal and biological analyses. The few studies that report trace metal or biological measurements suggest elevated trace metal concentrations or biological contamination that could be of concern to public health. We discuss the potential for fog and dew harvesting technologies and the need for trace metal and biological analyses of these waters before use. Key Points: Fog and dew are potential ancillary potable resources, but there are potential human health concernsCurrent fog and dew harvesting methods could be significantly improvedFog and dew should be treated before use as potable water [ABSTRACT FROM AUTHOR]

Abstract: Being a potential water source in arid and semiarid regions, it is important to quantify the amount of dew. The objective of this study was to determine the annual formation characteristics of dew and the influence of vegetation reconstruction on dew formation in a revegetated desert area. Effects of condensing surface types associated with different plant microhabitats were investigated. We found soil dew mainly depended on air water vapour near soil surface, and primarily formed at 0–3 cm soil layer. Dew formed on 128 days during a 1‐year experiment period could be divided into 2 different periods; the monthly dew yield and the number of dew formation days were highest from May to October, and the cumulative dew yield of July and August accounted for nearly 50% of the annual dew yield. Biological soil crusts facilitated dew formation, with annual dew accumulation of 15.3, 11.9, and 9.6 mm on moss crust, mixed crust, and dune sand, respectively. A longer daily dew production period was found on moss crusts than mixed crusts and dune sand. Plant microhabitats also influenced dew formation characteristics, less dew condense under plant canopies than on dune sand, but the daily dew production period was longer under plant canopies. The findings from this study will provide important and fundamental information to support accurate assessment of the relative importance of dew and rainfall in research on the hydrological cycle of this region, which will be a significant foundation for vegetation protection and ecological restoration in drought environments. [ABSTRACT FROM AUTHOR]

In an arid region, water is the limiting factor for the performance of plants and, hence, the input of water significantly affects the ecological processes. Although the dew phenomenon often occurs in the desert, whether plants can absorb and utilise this water source is still unknown. In this study, we tested the effects of 3 amounts of dew, that is, total natural amount of dew, half amount of natural dew, and no amount of (zero) dew, in order to investigate variations in functional traits and demographic traits in relation to the life history of an ephemeral plant Lappula semiglabra. Results showed that variations in functional traits including plant height, crown area, leaf area, leaf thickness, leaf relative water content, chlorophyll content, and net photosynthetic rate were significantly increased with increasing dew amount. Leaf water potential was significantly decreased, whereas root length and root diameter showed no significant differences among 3 amounts of dew. Demographic traits including survival rate, survival, total age, and mean life expectancy increased with increasing dew amount, whereas the vanish rate percentage, mortality rate, mortality, and fatal number decreased. In combination, our results showed that leaf and stem traits L. semiglabra related to dew absorption increased with increasing of dew amount, and hence, obtained more water, whereas root traits related to uptake of soil water remain unchanged. We conclude that leaves and stem of L. semiglabra can absorb and efficiently utilise dew as a water resource for better suitability in the arid desert region. [ABSTRACT FROM AUTHOR]

Precipitation is usually the primary source of water for the hydrological cycle in a semiarid area. However, dew occurs frequently and affects water circulation dramatically in the west of Jilin Province in China. Measurements of the amount of dew formed and precipitation were carried out from July 2012 to October 2013 in the Momoge Natural Reserve. The results indicated that moisture from primary precipitation in the summer originated from the East Asian monsoon and was affected by the atmospheric circulation in the middle and high latitudes of Eurasia in the winter. The dew amount was approximately 19.44 mm (approximately 5% of the total rainfall amount), consisting of the evapotranspiration in the local area and atmospheric moisture. Dew also supplies nutrients to the local vegetation. The maximum contribution of total nitrogen, total phosphorus, and potassium in unit corn area could reach 288.60, 27.46, and 291.63 mg/m2 in half a month, respectively. The wind speed, relative humidity, and lowest temperature were the primary factors that dramatically affected dew formation and amount. As an additional source of fresh water, dew not only had a positive impact on the ecosystem in arid and semiarid zones but also played an important role in the local water cycle and other ecological processes. This research has important implications for water circulation and land use management. [ABSTRACT FROM AUTHOR]

The arid and semi-arid drylands of the world are increasingly recognized for their role in the terrestrial net carbon dioxide ( CO2) uptake, which depends largely on plant litter decomposition and the subsequent release of CO2 back to the atmosphere. Observed decomposition rates in drylands are higher than predictions by biogeochemical models, which are traditionally based on microbial (biotic) degradation enabled by precipitation as the main mechanism of litter decomposition. Consequently, recent research in drylands has focused on abiotic mechanisms, mainly photochemical and thermal degradation, but they only partly explain litter decomposition under dry conditions, suggesting the operation of an additional mechanism. Here we show that in the absence of precipitation, absorption of dew and water vapor by litter in the field enables microbial degradation at night. By experimentally manipulating solar irradiance and nighttime air humidity, we estimated that most of the litter CO2 efflux and decay occurring in the dry season was due to nighttime microbial degradation, with considerable additional contributions from photochemical and thermal degradation during the daytime. In a complementary study, at three sites across the Mediterranean Basin, litter CO2 efflux was largely explained by litter moisture driving microbial degradation and ultraviolet radiation driving photodegradation. We further observed mutual enhancement of microbial activity and photodegradation at a daily scale. Identifying the interplay of decay mechanisms enhances our understanding of carbon turnover in drylands, which should improve the predictions of the long-term trend of global carbon sequestration. [ABSTRACT FROM AUTHOR]

Spatial variability in lithobiont-induced weathering patterns on desert rocks is aspect-dependent. While differences between the northern and southern aspects have been extensively studied, little is known concerning the differences between east-facing (EF) and west-facing (WF) aspects in deserts, including the Negev Desert. Whereas cobbles on both slopes are inhabited by endolithic lichens, epilithic lichens, which render the bedrock a smooth appearance, and free-living cyanobacteria, which give the bedrock a rugged microrelief, predominate on WF and EF bedrock, respectively. Following previous research that regarded dew as the principal factor that determines lithobiont distribution, measurements of radiation, temperature, wind and dew were carried out during 2008-2009 in the Negev Desert. The data indicated that albeit slightly higher midday surface temperatures that characterize WF surfaces (cobbles and bedrock), nocturnal temperatures on these surfaces were significantly lower, therefore facilitating higher dew condensation. High amounts of dew result from the relatively rapid drop in temperatures (14:00-20:00) due to the afternoon northwesterly sea-breeze wind (with a cooling rate of the WF bedrock being 52.9% higher than on EF bedrock, 2.6 °C h−1 in comparison to only 1.7 °C h−1), and facilitate the growth of high-chlorophyll dew-fed (and rain-fed) epilithic lichens, which may act as bio-protectors on WF bedrock. Lack of condensation on EF bedrock results in turn in the growth of rain-fed free-living cyanobacteria, responsible for high rock dissolution and subsequently for a rugged microrelief. By affecting the nocturnal bedrock temperatures, wind acts as a cooling agent, impacting in turn the amount of dew, and subsequently lithobiont composition and weathering patterns in the Negev Desert. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Dewfall is widely recognized as an important source of water for many ecosystems, especially in arid and semiarid areas, contributing to improve daily and annual water balances and leading to increased interest in its study in recent years. In this study, occurrence, frequency and amount of dewfall were measured from January 2007 to December 2010 (4 years study) to find out its contribution to the local water balance in a Mediterranean semiarid steppe ecosystem dominated by scattered tussocks of Stipa tenacissima (Balsa Blanca, Almería, SE Spain). For this purpose, we developed a dewfall measurement method, 'The Combined Dewfall Estimation Method' (CDEM). This method consists of a combination of the potential dewfall model, i.e. the single-source Penman-Monteith evaporation model simplified for water condensation, with information from leaf wetness sensors, rain gauge data, soil surface temperature and dew point temperature. To assess the reliability of the CDEM, dewfall was measured in situ using weighing microlysimeters during a period of 3 months. Daily micrometeorological variables involved in a dewfall event were analysed in order to assess the significance of dewfall at this site. Dewfall condensation was recorded on 78% of the nights during the study period. Average monthly dewfall duration was 9.6 ± 3.2 h per night. Average dewfall was 0.17 ± 0.10 mm per night and was mostly dependent on dewfall duration. Dewfall episodes were longer in late autumn and winter and shorter during spring. Annual dewfall represented the 16%, 23%, 15% and 9% of rainfall on 2007, 2008, 2009 and 2010, respectively. Furthermore, when a wet period was compared to a dry one, the dewfall contribution to the water balance at the site was found to be 8% and 94%, respectively. Our results highlight the relevance of dewfall as a constant source of water in arid ecosystems, as well as its significant contribution to the local water balance, mainly during dry periods where it may represent the only source of water at the site. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Dew, as a supplementary water source, may have an important ecological role in arid and semi-arid regions. During August and September of 2007 and 2008, measurements were taken to investigate the dew accumulation and evaporation patterns in the very early morning hours, in three different habitats (dunetop, footslope, and interdune lowland) of a fixed sand dune in Northwest China. Dew quantities were measured using the cloth-plate method. The results indicated that there was a positive correlation between dew amounts and relative humidity, but a negative correlation between dew amounts and mean temperature. Clear mornings were characterized by higher dew amounts and longer dew duration, whereas less dew was recorded during cloudy and especially windy mornings. Dew continued to condense even after sunrise, although a shorter warming time after dawn is also of vital importance in dew formation. The higher average maximum dew quantities (0.06 mm) and longer average dew duration (2.3 h) occurred in the interdune lowland; the lower and shorter average dew amounts (0.048 mm) and duration (1.9 h) were obtained at the dune top. The footslope habitat exhibited intermediate values. Clearly, the differences in dew deposition can be partially attributed to the distinguishing characteristics of the microhabitats. The present study highlighted the impacts of these characteristics on near-ground dew condensation accumulation and evaporation in a fixed sand dune and may facilitate evaluation of the role of dew in arid and semi-arid environments. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Dwarf succulents persist in the arid Succulent Karoo despite the low-water storage capacities of their contracted leaves and stems that are inadequate for enduring severe and prolonged drought. We examined the contribution of non-rainfall moisture (fog, dew, water vapour) to the water budgets and relative abundance of two endemic dwarf succulents Agyroderma pearsonii and Cephalophyllum spissum. Non-rainfall moisture was measured with automated lysimeters containing bare quartz-gravel soils and introduced A. pearsonii and C. spissum individuals at hourly intervals spanning an 8-month wet winter to dry summer period. Total non-rainfall atmospheric moisture intercepted by the bare quartz-gravel substrate of 137·6 mm, of which water vapour adsorption contributed 56·2 mm, fog 78·2 mm and dew 3·4 mm, was virtually equivalent to the rainfall amount of 142·7 mm. Agyroderma pearsonii intercepted 228·4 mm of non-rainfall moisture of which water vapour adsorption contributed 117·1 mm, fog 104·4 mm and dew 6·9 mm. This was nearly three times the non-rainfall amount of 88·7 mm y−1 intercepted by C. spissum, of which water vapour contributed 44·3 mm, fog 41·3 mm and dew 3·1 mm. The greater quantity of non-rainfall moisture intercepted by A. pearsonii corresponded with its threefold greater leaf abundance and twofold greater canopy cover than that of C. spissum. We conclude that non-rainfall moisture, especially the absorption of atmospheric water vapour by soils and its uptake by the extensive network of superficial roots of dwarf quartz-field succulents are vital in sustaining their growth and survival and in determining their distributions and relative abundance. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Investigations were conducted to determine the pollution levels of air condensate and rain samples using the enhanced chemiluminescence ( ECL) reaction. Air condensate samples were initially collected from roadside sites, non-roadside sites, smoking-exposed sites and non-smoking-exposed sites using an automatic dew collector. Rainwater was also collected throughout the sampling period. Samples were subsequently analysed using the ECL reaction, and pollution levels ( Eclox Units) were calculated. Air condensate samples collected from roadside- and smoking-exposed sites generally had higher pollution levels than those from non-roadside- and non-smoking-exposed sites. Samples from both smoking-exposed and traffic-exposed sites generally had higher pollution levels than rainwater. Finally, in samples collected from roadside-exposed sites and rainwater, the main polluting constituents were determined to be cationic/anionic components. In samples collected from smoking-exposed sites, the main polluting constituents were determined to be organic components. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]