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A power generator comprising a thermoelectric device (TED) and a phase change material (PCM) allows energy harvesting from ambient temperature variations, which exist ubiquitously; thus, such a device has received considerable attention as an energy harvester that can operate at any location. We developed a model for estimating the characteristics of a power generator in ambient air, whose temperature is forcibly changed between two temperature values, such as when an air conditioner is turned on and off. We calculated the influence of latent heat and thermal conductivity of the PCM on the characteristics of power generators with various thermal resistances between the TED/PCM interface and ambient air. Latent heat and thermal conductivity of the PCM affect the amount of heat energy (Q) transfer between the ambient air and PCM and the energy conversion efficiency (ηE), respectively, where the amount of electric energy is given by Q × ηE. The increase in Q caused by an increase in the latent heat of the PCM was almost independent of the thermal resistance between the TED/PCM interface and air. However, the increase in ηE caused by an increase in the thermal conductivity of the PCM decreased as the thermal resistance between the TED/PCM interface and air increased. These results indicate that the techniques to improve the power generation characteristics by increasing the thermal conductivity of PCM, which have been frequently investigated in recent years, are effective only when the thermal resistance between the TED/PCM interface and ambient air is small. [ABSTRACT FROM AUTHOR]

When a contact line (CL)—where a liquid–vapor interface meets a substrate—is put into motion, it is well known that the contact angle differs between advancing and receding CLs. Using non-equilibrium molecular dynamics simulations, we reveal another intriguing distinction between advancing and receding CLs: while temperature increases at an advancing CL—as expected from viscous dissipation, we show that temperature can drop at a receding CL. Detailed quantitative analysis based on the macroscopic energy balance around the dynamic CL showed that the internal energy change of the fluid due to the change of the potential field along the pathline out of the solid–liquid interface induced a remarkable temperature drop around the receding CL, in a manner similar to latent heat upon phase changes. This result provides new insights for modeling the dynamic CL, and the framework for heat transport analysis introduced here can be applied to a wide range of nanofluidic systems. [ABSTRACT FROM AUTHOR]

Kinetic theory has long predicted that temperature inversion may happen in the vapor-phase for evaporation and condensation between two parallel plates, i.e., the vapor temperature at the condensation interface is higher than that at the evaporation interface. However, past studies have neglected transport in the liquid phases, which usually determine the evaporation and condensation rates. This disconnect has limited the acceptance of the kinetic theory in practical heat transfer models. In this paper, we combine interfacial conditions for mass and heat fluxes with continuum descriptions in the bulk regions of the vapor and the liquid phases to obtain a complete picture for the classical problem of evaporation and condensation between two parallel plates. The criterion for temperature inversion is rederived analytically. We also prove that the temperature jump at each interface is in the same direction as externally applied temperature difference, i.e., liquid surface is at a higher temperature than its adjacent vapor on the evaporating interface and at a lower temperature than its adjacent vapor on the condensing interface. We explain the interfacial temperature jump and temperature inversion using the interfacial cooling and heating processes, and we predict that this process can lead to a vapor phase temperature much lower than the lowest wall temperatures and much higher than the highest wall temperature imposed. When the latent heat of evaporation is small, we found that evaporation can happen at the low temperature side while condensation occurs at the high temperature side, opposing the temperature gradient. [ABSTRACT FROM AUTHOR]

Alloy phase change materials (PCM) are key materials in latent heat storage systems for solar thermal power generation, however, their application is limited by the high corrosion and oxidation problems of alloys. To reduce the erosion problem of alloy PCM, SiC-based ceramic encapsulated flake graphite (EG) modified Al-Cu28-Si6 alloy was used to successfully prepare composite PCM with high compatibility and oxidation resistance. Adopting static erosion test method, the composite PCM was subjected to 50 thermal cycles (25–1000 °C holding time of 10 h was recorded as 1 cycle). The results showed that SiC-based ceramics have excellent corrosion resistance to composite PCM with 10 wt% EG added, which due to the excellent reticulation and encapsulation of EG. Based on the Young-Laplace equation and the contact angle, the erosion resistance mechanism of silicon carbide ceramic alloys has been revealed. SiC-based ceramic-PCM sensible heat-latent heat composite heat storage material was expected to be used for high-temperature heat storage in solar thermal power generation. [ABSTRACT FROM AUTHOR]

The critical role of latent heating (LH) in atmospheric blocking events is well-recognized, yet its influence on the predictability of such events remains underexplored. This study examines the prediction accuracy of winter atmospheric blocking days over the Northern Hemisphere, utilizing 20 years of retrospective forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). Atmospheric blocking events are categorized into three sectors: Atlantic, Continent, and Pacific. Results indicate substantial variations in the LH contribution among different blocking events. During the first 21 days, the Pacific blockings exhibit the most significant impact on prediction skill under strong LH conditions, followed by the Continent blockings, with the Atlantic blockings being least affected. Interestingly, a consistent pattern emerged across sectors: blocking prediction skill is lower under strong LH than under weak LH. During the first 12 days, the Pacific sector typically exhibit lower prediction skill for blocking onset under strong LH, compared to weak LH. For blocking decay, a consistent pattern is observed: lower prediction skill under strong LH than weak LH. Regarding blocking intensity, the forecasting bias escalates with increasing lead time, particularly for strong LH. This study highlights the need to improve moist process simulations in models, aiming to improve atmospheric blocking forecasting accuracy. [ABSTRACT FROM AUTHOR]

Carbon nanomaterial-based form stable phase change materials (FSPCM) offer significant potential as energy storage materials. However, the timely review respectively summarizing the evolution of each carbon nanomaterial and their differences is still lacking. Herein, a comprehensive and systematic approach to gathering, analyzing, and synthesizing relevant literature is employed to conduct this review paper. Specifically, this review provides an extensive examination of PCM encapsulation techniques employing carbon nanomaterial-based materials, discussing their underlying mechanisms and strategies for improving thermal performance. Additionally, it explores the practical applications of carbon nanomaterial-based FSPCMs and discusses future avenues for research and development in this field. By focusing on advancing encapsulation techniques, improving performance, and expanding application possibities, this review aims to contribute to the ongoing progress in the field of carbon nanomaterial-based FSPCMs. [ABSTRACT FROM AUTHOR]

Phase change energy storage microcapsules were synthesized in situ by using melamine-formaldehyde–urea co-condensation resin (MUF) as wall material, n-octadecane (C18) as core material and styryl-maleic anhydride copolymer (SMA) as emulsifier. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis were used to study the effects of emulsifier type, emulsifier dosage, core–wall ratio and pH on the morphology and thermal properties of microcapsules. The results show that the pH of core material and the ratio of core to wall have a great influence on the performance of microcapsules. SMA emulsifiers and MUF are suitable for the encapsulation of C18. When the pH is 4.5 and the core–wall ratio is 2/1, the latent heat and encapsulation efficiency of phase transition reaches 207.3 J g−1 and 84.7%, respectively. The prepared phase-change microcapsules also have good shape stability and thermal stability. [ABSTRACT FROM AUTHOR]

Oxygen atoms have been widely used in porous organic polymers, which has attracted much attention from researchers. Herein, porous organic polymer with high oxygen content is synthesized with oxygen‐rich monomer as construction unit and anhydrous aluminum chloride as catalyst; then phase‐change materials (PCMs) composites are prepared by self‐adsorption method. The pore properties of the oxygen‐rich porous organic polymer are characterized by nitrogen absorption and desorption method. The properties of the PCM composites are characterized by scanning electron microscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The results show that the oxygen‐rich porous organic polymer has high Brunauer–Emmett–Teller surface area (465 m2 g−1) and excellent thermal stability. The PCM composites possess high encapsulation rate (50.6 wt%) and latent heat (124.7 kJ g−1). After several thermal cycles, the thermal properties of all PCM composites are almost unchanged, and no leakage phenomenon is found. It can be seen that oxygen‐rich porous polymers have potential applications in PCM adsorption and thermal energy storage. [ABSTRACT FROM AUTHOR]

The < 110 > directional solidification of silicon under varying overall temperature gradients was investigated using an in situ observation system. The growth velocity of an atomically rough interface was found to decrease with increasing temperature gradient. A theoretical model of the thermal field taking undercooling into account was developed to describe this phenomenon and was demonstrated to be valid. The results of this work indicate that the reported linear relationship between growth velocity (V) and undercooling (ΔT), given by V (mm s−1) = 120ΔT (K), is most accurate in the case of a rough interface. In the case that the overall temperature gradient is small, the melting point isotherm moves rapidly such that it becomes more difficult for the interface to keep pace with the isotherm compared with a large temperature gradient. This effect leads to increased undercooling at the interface and consequently a rapid growth velocity. Thermal field calculations confirm that a rapid increase in the ratio of the temperature gradient in the crystal to that in the melt should increase the latent heat release, again providing a more rapid growth velocity. [ABSTRACT FROM AUTHOR]

The equatorward contraction of tropical precipitation, commonly referred to as the "deep‐tropical contraction", is witnessed in the paleoclimate simulations of the early Eocene. However, the mechanism driving this contraction is still unclear. Based on the energetics framework of the Intertropical Convergence Zone (ITCZ) and the decomposition method of the latent heat flux along with the simulations of a climate system model, CESM1.2, we proposed a novel mechanism responsible for the "deep‐tropical contraction" in the early Eocene. The greenhouse gases‐induced sea surface warming amplifies the sensitivity of evaporation to surface wind speed changes through Clausius‐Clapeyron scaling, leading to an interhemispheric asymmetric enhancement of the latent heat flux. To maintain hemispheric energy balance, the cross‐equatorial atmospheric energy transport must be reduced during the solstice seasons. As a result, the solstitial location of the ITCZ shifts equatorward, causing the "deep‐tropical contraction" in the early Eocene. Plain Language Summary: The early Eocene is the warmest epoch in the last 65 million years, with a global mean temperature 9°C–23°C higher than the preindustrial period. According to state‐of‐the‐art climate models, the tropical rainfall contracted toward the equator during this extremely warm period. However, the physical mechanism causing this phenomenon remains unclear. In this study, we examined the hemispheric energy balance in the early Eocene that causes the equatorward contraction of tropical precipitation. A novel mechanism underlying this phenomenon is revealed. Based on the climate modeling of CESM1.2, we show that the GHG‐induced warmth enhances the sensitivity of evaporation to surface wind speed changes in the early Eocene. Thus, the stronger tropical trade wind in the winter hemisphere will drive out stronger latent heat flux than in the summer hemisphere. This interhemispheric asymmetric response reduces the interhemispheric heating contrast in the solstice seasons. As a result, the ascending motion in the tropical atmosphere migrates toward the equator, finally decreases the width of tropical precipitation in the early Eocene. Key Points: The "deep tropical contraction" in the early Eocene is caused by the equatorward migration of the seasonal ITCZThe equatorward migration of the solstitial ITCZ location in the early Eocene is due to decreased cross‐equatorial energy transportThe enhanced wind‐evaporation effect in the early Eocene reduces the cross‐equatorial atmospheric energy transport in the solstitial seasons [ABSTRACT FROM AUTHOR]

[Display omitted] Phase change materials (PCMs) can store and release latent heat under the designed phased change temperature and have received substantial interest for energy conservation and thermal control purposes. The use of PCMs in the construction of constant temperature buildings can improve the comfortable environment and save more energy. However, the leakage of PCMs during phase change process limits the application of PCMs. In this paper, a series of PCMs microcapsules with controllable core numbers is synthesized with paraffin (37 ℃) as the core and cross-linked chitosan as the wall. The single-core phase-change microcapsules (S−PCM) and multicore phase-change microcapsules (M−PCM) were prepared by adjusting the preparation condition. The latent heat of S−PCM and M−PCM are 61.4 mJ mg−1 and 50.1 mJ mg−1, respectively. The S-PCM and M−PCM display good stability without paraffin leakage. In addition, the composite blocks of gypsum and S−PCM (GSCM) and M−PCM (GMCM) were prepared and the thermoregulatory effection was investigated, where the surface temperature of GSCM was 5–10 ℃ lower than that of pure gypsum block. PCMs may also have broad application space in electronics, cold chain, and other industries. [ABSTRACT FROM AUTHOR]

Among metal‐based phase change materials (PCMs), Al and its alloys have garnered significant attention due to their high latent heat and high thermal conductivity. However, challenges such as leakage, corrosion, and oxidation have limited their widespread application. Numerous researches have demonstrated that encapsulating Al and its alloy PCMs is one effective way to address these problems. This review provides a comprehensive overview of the characteristics, encapsulation strategies, and applications of Al and its alloy PCMs. First, the advantages and thermal properties of Al and its alloy PCMs are introduced, and their problems are then discussed. Subsequently, various encapsulation strategies that are expected to solve the above problems are summarized and compared. Additionally, the applications of Al and its alloy PCMs in solar thermal energy storage, catalysis, and electric vehicles are reviewed. Finally, current challenges, potential solutions, and the key direct of future study are presented. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have emerged as an intriguing option for the storage of thermal energy because of their remarkable capacity to store latent heat. However, the practical application of these materials is hindered by their low thermal conductivity and limited photo-absorbance. For this investigation, graphene nanoplatelets (GNP) and multiwall carbon nanotubes (MWCNT) hybrid nanoparticles were disseminated in RT-54HC organic PCMs at different weight fractions. The nanoparticles were incorporated into the base PCMs using a melt blending technique. Based on the findings, one combination of GNP to MWCNT in a 0.25:0.75 ratio has shown the highest thermal conductivity, with an increase of 40% (0.28 Wm−1 K−1) compared to other hybrid combinations. This breakthrough could potentially open new avenues in the field of thermal energy storage. The chemical stability of the hybrid nanoparticle dispersed composites was assessed through FTIR analysis. In addition, the composites exhibited excellent thermal stability, maintaining their structural integrity even at temperatures as high as 300 ℃. The melting temperature of the composites also showed minimal variation. Based on the evaluation of latent heat enthalpy, the organic PCM known as base RT-54HC demonstrated a heat storage capacity of 230 J/g. However, the composites exhibited a slight decrease in latent heat with increasing nanoparticle weight fraction. In addition, the composite with added hybrid nanoparticles demonstrated an increase in optical absorbance, accompanied by a decrease in transmissibility. Therefore, the hybrid nano-enhanced composites have demonstrated enhanced thermo-physical properties, making them not only suitable but also highly promising for use in applications with mid-range melting temperatures. [ABSTRACT FROM AUTHOR]

An unprecedented heavy rainfall event in China ("21.7" extreme rainfall event) was simulated using the global variable‐resolution model (MPAS‐Atmosphere) across the scales (4, 8, 16 and 50 km). Although almost all experiments at different resolutions reproduce the spatiotemporal characteristics of precipitation, the simulated precipitation intensity from high to low is 16, 8, 50, and 4 km, with the 16 km simulation being closest to the observations. Precipitation magnitude is prominently influenced by the difference in simulated large‐scale circulation across a range of grid spacings. Further analysis revealed that the differences in latent heating across scales affect the geopotential height and wind field by altering temperature. The latent heating in 4 km simulation is the minimum while the 16 km simulation is maximum. More latent heating release leads to the low‐level pressure depression, amplifies the water vapor flux convergence, produces stronger upward motion and more clouds, and ultimately results in stronger precipitation. The sensitivity experiments for turning off latent heating tendencies during the event showed that the latent heat release has positive feedback on the "21.7" heavy rainfall event. This study highlights the importance of scale‐awareness of latent heat at different resolutions and suggests that the difference in simulated latent heat release during the event is the main reason for simulated different atmospheric circulation and precipitation across scales. Plain Language Summary: Due to the advancements in the numerical computing power, numerical weather prediction models (NWP) are operating at horizontal grid spacing ranging from 1 to 10 km. This study evaluates the simulation performance of the global variable‐resolution model MPAS‐A for a heavy precipitation event and investigates the influence of scale‐aware convective parameterizations on modeling rainfall at horizontal resolutions across the scales (4, 8, 16 and 50 km). The results show that 4 km simulation exhibits the weakest precipitation while the simulated precipitation at 16 km is the strongest. The difference in precipitation simulated by four experiments across scales derives from the variations in large‐scale circulation simulated with different refined resolutions. Further analysis revealed that the differences in latent heat at different resolutions ultimately lead to the changes in geopotential height and large‐scale wind field by altering temperature. 4 km experiment simulates less latent heat than other lower‐resolution experiments. Owing to the positive feedback of the latent heat release on precipitation, 4 km experiment simulates the minimum precipitation. This work highlights that latent heat plays a vital role in simulation of synoptic condition and precipitation. Key Points: Precipitation is influenced by the difference in simulated atmospheric circulation across a range of grid spacingsThe differences in simulated latent heat release across scales affect the geopotential height and wind field by altering temperatureThe latent heat release has positive feedback impact on the "21.7" heavy precipitation event [ABSTRACT FROM AUTHOR]

Persistent positive sea surface temperature anomalies (SSTAs) in the mid‐latitude Northeast Pacific (NEP), also known as "warm blob" or "marine heatwave," have substantial ecological and climate effects. This study delves into the spatiotemporal connection between Arctic Oscillation (AO) and SSTAs in the NEP. First, we conduct the lead‐lag correlation and maximum covariance analyses to disentangle the closest temporal relationship between October AO and wintertime SSTAs in the NEP. Then, we categorize the years in positive AO (pAO) phase into two groups: positive AO with warm anomaly (pAO&Blob) group and positive AO without warm anomaly (pAO&noBlob) group based on the October AO index and wintertime blob index. Results show that the positive phase of AO in October strongly influences the wintertime warm SSTAs in the NEP through local and remote pathways. The local pathway is contingent upon the longitudinal positioning of AO‐related high‐pressure anomaly (i.e., anomalous ridge) in the North Pacific. When easterly anomalies prevail at the southern flank of the anomalous ridge over the NEP, they foster warm SSTAs in the NEP. However, different locations of the high‐pressure anomalies may impede the NEP warming. Remote pathways indicate the teleconnections triggered by AO‐related precipitation increase in Greenland and decrease in East Asia, sustaining the high‐pressure anomaly and promoting the anomalous NEP warming. Hence, this study presents new evidence on polar and mid‐latitude climate connections, which may provide potential predictability for the warm SSTAs in the NEP. Plain Language Summary: Under rapid climate change, long‐lasting warm sea surface temperature anomalies (SSTAs) in the mid‐latitude Northeast Pacific (NEP) have attracted wide attention due to their substantial ecological and climate effects. Arctic Oscillation (AO) is the dominant mode of atmospheric circulation variability in mid‐to‐high latitudes of the Northern Hemisphere. Its positive phase is featured by a low‐pressure center in the Arctic region and high‐pressure centers in the mid‐latitude regions. Our results reveal a robust connection between the positive phase of AO in October and warm SSTAs in the NEP during winter. We identify two primary pathways through which the October AO influences the wintertime sea surface temperature (SST) warming in the NEP. Locally, a high‐pressure anomaly over the NEP is associated with easterly wind anomalies to its southern flank, which diminish oceanic latent heat loss to the atmosphere, thus fostering the SST warming in the NEP. However, other locations of the high‐pressure anomaly related to AO may not be favorable for the warming of the NEP. From a remote view, AO can impact the NEP SST through teleconnections due to increased precipitation in Greenland and decreased precipitation in East Asia, sustaining the high‐pressure anomaly over the NEP and further bolstering the NEP warming. Key Points: Temporally, Arctic Oscillation (AO) in October is closely linked to wintertime sea surface temperature (SST) anomalies in the mid‐latitude Northeast Pacific (NEP)The AO‐related anomalous ridge located over the NEP is favorable for the warming of SST locallyRemotely, enhanced rainfall in Greenland and decreased rainfall near East Asia sustain the anomalous ridge over the NEP via teleconnection [ABSTRACT FROM AUTHOR]

Evaporative fraction (EF) is a useful measure for quantifying land surface energy partitioning processes and determining evaporative regimes; however, its influencing factors remain highly uncertain. Here, global data sets were compiled to disentangle the effects of environmental variables on EF variations along climate and land surface gradients. We found that (a) at annual timescales, ecosystem‐level EF could be expressed as a power law function of aridity index. The relationships of mean annual soil water content (SWC) and leaf area index (LAI) with mean annual EF resembled the traditional evaporative regime theory; (b) at daily timescales, the boosted regression tree method quantitatively revealed that the impacts of environmental variables (including meteorological variables) on EF showed equal importance, especially at humid sites, primarily due to the different response direction and magnitude of latent heat (LE) and sensible heat (H) fluxes to environmental changes. Particularly, the contrasting responses of LE (positive) and H (negative) to SWC, LAI, and relative humidity enhanced the positive effects of those influencing variables on EF; whereas, the correlations between EF and energy‐related factors (i.e., net radiation‐Rn and air temperature‐Ta) deteriorated as both LE and H showed positive response patterns to those variables; (c) meteorological factors were also found to have nonlinear effects on daily EF, further modified by climatic conditions. Rn near 150 W/m2 and Ta near 15°C appeared to be important energy‐partitioning thresholds at drier and humid sites, respectively. Moreover, changing interactions among environmental variables with climates were demonstrated to be important for better explaining EF variations. Plain Language Summary: Evaporative fraction (EF; defined as latent heat flux‐LE divided by the sum of LE and sensible heat flux‐H) can vary under different climatic and land surface conditions, but its influencing factors remain poorly understood. To this end, we explored the effects of environmental variables on annual and daily EF variations at different sites around the globe. We found that mean annual EF decreased with increasing aridity index and increased with mean annual soil water content and leaf area index. By comparison, the boosted regression tree method quantitatively showed that environmental variables exerted equally important roles in regulating daily EF, especially at humid sites. The complex interplays of daily EF with environmental variables were mainly due to the different responses of LE and H to surrounding environments and the strong nonlinear and interactive effects of environmental variables. These results are important for understanding the driving mechanisms of EF and land surface energy partitioning processes along climate and land surface gradients. Key Points: Environmental variables exerted equally important roles in regulating daily evaporative fraction, especially at humid sitesSynchronous responses of latent and sensible heat to surroundings determined how environmental variables affected evaporative fractionEnvironmental factors had strong nonlinear and interactive effects on daily evaporative fraction, which was further modified by climates [ABSTRACT FROM AUTHOR]

El Niño typically induces cooling in the Southwest Pacific Ocean during austral summers, usually leading to decreased marine heatwave frequency and severity. However, the 2016 extreme El Niño unexpectedly coincided with the longest and most extensive marine heatwave ever recorded in the region. This heatwave, spanning over 1.7 million square kilometers, persisting for 24 days with a peak intensity of 1.5°C, resulted in massive coral bleaching and fish mortality. This exceptional warming resulted from anomalously strong shortwave radiation and reduced heat loss via latent heat fluxes, owing to low wind speed and increased air humidity. These anomalies are attributed to a rare combined event "Madden-Julian Oscillation and extreme El Niño." Following 10 February, the rapid dissipation of this marine heatwave results from the most intense cyclone ever recorded in the South Pacific. The hazardous ecological impacts of this extreme event highlight the needs for improving our understanding of marine heatwave-driving mechanisms that may result in better seasonal predictions. [ABSTRACT FROM AUTHOR]

The evolution of Storm Ciarán was different from what is commonly attributed to windstorms affecting northwest Europe. Ciarán initially developed as a diabatic Rossby wave, driven by low‐level latent heat release and with negligible upper tropospheric forcing. It then crossed the jet stream, intensifying explosively while developing a low‐level warm seclusion and producing extreme near‐surface winds, including sting jets. Ciarán is an example of an extreme windstorm following this pathway and highlights the need of a systematic assessment of its relevance in our warming climate. [ABSTRACT FROM AUTHOR]

The Mechanical properties of concrete significantly deteriorate when exposed to fire, with explosive spalling posing a major threat to structural integrity. This highlights the need for effective insulation systems to protect concrete structures in fire conditions. However, current insulation solutions are typically installed externally, requiring additional labour and materials. This review explores the potential of incorporating Phase Change Materials (PCMs) directly into concrete as an embedded insulation system. As a latent heat storage material, PCM offers promising fire-resistant properties, reducing the need for external insulation while improving the fire performance of concrete. This paper presents a bibliometric analysis and a systematic review of recent publications on the use of PCMs in concrete and their fire performance applications. One thousand two hundred and four publications retrieved from Scopus© and Web of Science databases were passed through the PRISMA flowchart to obtain a database of recent literature on the study area. The current trend of research shows a shift towards inorganic PCMs in concrete. There is a significant lack of studies on using inorganic and eutectic PCM in concrete for fire applications and existing studies show inorganic PCM can be a viable solution. Commercial availability and lack of synthesised encapsulated PCM were found to be barriers to research. [ABSTRACT FROM AUTHOR]

Phase change material (PCM)‐based heat storage systems utilize the absorption or release of latent heat during a phase change of the storage material to store thermal energy. Nevertheless, the effectiveness of these systems is restricted by the shape and structure of their confinement, as well as the heat conductivity of the storage material. This work investigates a novel method to enhance the effectiveness of PCM systems by concurrently utilizing two techniques: the inclusion of nanoparticles and the alteration of the system's geometry. Introducing nanoparticles enhances the thermal conductivity of the storage medium while altering the shape, which improves heat transfer efficiency by adjusting the surface area available for heat exchange. RT‐35 was tested for use in latent heat thermal energy storage systems for space heating and cooling. With a melting point of 35°C, RT‐35 was chosen to moderate building temperatures by storing and releasing thermal energy for space heating and cooling. The results indicate that using nanoparticles and adjusting shape can greatly enhance the effectiveness of PCM systems. By incorporating Al2O3 nanoparticles, the melting time of the PCM was reduced by 20% compared to the pure PCM, and it is more efficient than the best case of shape modification. These findings indicate that including nanoparticles and modifying the shape are effective methods to improve the performance of heat storage devices. This technology's potential surpasses this study's limits and can be utilized in diverse applications, including solar thermal energy storage, district heating and cooling, and industrial process heat. [ABSTRACT FROM AUTHOR]

Urban Land Surface Models (ULSMs) simulate energy and water exchanges between the urban surface and atmosphere. However, earlier systematic ULSM comparison projects assessed the energy balance but ignored the water balance, which is coupled to the energy balance. Here, we analyze the water balance representation in 19 ULSMs participating in the Urban‐PLUMBER project using results for 20 sites spread across a range of climates and urban form characteristics. As observations for most water fluxes are unavailable, we examine the water balance closure, flux timing, and magnitude with a score derived from seven indicators expecting better scoring models to capture the latent heat flux more accurately. We find that the water budget is only closed in 57% of the model‐site combinations assuming closure when annual total incoming fluxes (precipitation and irrigation) fluxes are within 3% of the outgoing (all other) fluxes. Results show the timing is better captured than magnitude. No ULSM has passed all water balance indicators for any site. Models passing more indicators do not capture the latent heat flux more accurately refuting our hypothesis. While output reporting inconsistencies may have negatively affected model performance, our results indicate models could be improved by explicitly verifying water balance closure and revising runoff parameterizations. By expanding ULSM evaluation to the water balance and related to latent heat flux performance, we demonstrate the benefits of evaluating processes with direct feedback mechanisms to the processes of interest. Plain Language Summary: Urban environments have their own local climates including typically higher nocturnal temperatures compared with rural areas. Ideally, modeling cities should capture their influences on the atmosphere above them. As the energy and water balances are linked by evaporation, a good water balance representation will support a good energy balance simulation. Focusing on the water balance, we find the water balance in models could be improved by paying attention to closure and runoff. Key Points: We evaluate the water balance in 19 urban land surface models (ULSM) from the Urban‐PLUMBER projectULSMs capture the timing of water fluxes more accurately than their magnitudeThe water balance appears unclosed in 43% of the model runs (19 models at 20 sites) [ABSTRACT FROM AUTHOR]

Sea-effect snow (SES) is a meteorological phenomenon resulting from cold air moving over warmer waters. Accurate prediction of SES is vital for emergency management, transportation, and water resource planning. A thundersnow event in Istanbul from 17–19 February 2015 caused significant disruptions, with traffic and flights affected, highways temporarily closed, and trees falling due to heavy snowfall. This study investigates the influence of different parameterization schemes in the Weather Research and Forecasting (WRF) model on SES simulations. Six distinct PBL parameterization schemes were used in a series of WRF simulations. In addition, the following factors pivotal to SES event have also been investigated: 1000–500 hPa thickness, total and latent heat fluxes, radar and satellite analyses, temperature gradients, wind shear, inversion levels, and atmospheric stability indices. Additionally, the formation of SES during the cold front transition further contributed to these elements in the Black Sea region. The simulations displayed notably high total heat flux and latent heat flux values, particularly following the passage of the cold front. Furthermore, the northeast-southwest oriented SES cloud, distinguished by its banded structure, was successfully validated using radar and satellite imagery. However, it's worth noting that the model positioned it farther west than its actual location. This study highlights the challenges in precise prediction and analysis of such convective activities. In this thundersnow event, the local closure schemes, particularly MYNN in first place and second MYJ, demonstrated superior performance compared to non-local schemes within the parameterization options. [ABSTRACT FROM AUTHOR]

Solar energy is a primary form of renewable energy, and photothermal conversion is a direct conversion process with tunable conversion efficiency. Among various kinds of photothermal conversion materials, porous organic polymers (POP) are widely investigated owing to their controllable molecular design, tailored porous structures, good absorption of solar light, and low thermal conductivity. A variety of POP, such as conjugated microporous polymers (CMP), covalent organic frameworks (COF), hyper‐crosslinked porous polymers (HCP), polymers of intrinsic microporosity (PIM), porous ionic polymers (PIP), are developed and applied in photothermal conversion applications of seawater desalination, latent energy storage, and biomedical fields. In this review, a comprehensive overview of the recent advances in POP for photothermal conversion is provided. The micro molecular structure characteristics and macro morphology of POP are designed for applications such as seawater desalination, latent heat energy storage, phototherapy and photodynamic therapy, and drug delivery. Besides, a probe into the underlying mechanism of structural design for constructing POP with excellent photothermal conversion performance is methodicalized. Finally, the remaining challenges and prospective opportunities for the future development of POP for solar energy‐driven photothermal conversion applications are elucidated. [ABSTRACT FROM AUTHOR]

The increasing global population has intensified the demand for energy and food, leading to significant greenhouse gas (GHG) emissions from both sectors. To mitigate these impacts and achieve Sustainable Development Goals (SDGs), passive thermal storage methods, particularly using phase change materials (PCMs), have become crucial for enhancing energy efficiency and reducing GHG emissions across various industries. This paper discusses the state of the art of bio-based phase change materials (bio-PCMs), derived from animal fats and plant oils as sustainable alternatives to traditional paraffin-based PCMs, while addressing the challenges of developing bio-PCMs with suitable phase change properties for practical applications. A comprehensive process is proposed to convert bacon fats to bio-PCMs, which offer advantages such as non-toxicity, availability, cost-effectiveness, and stability, aligning with multiple SDGs. The synthesis process involves hydrolysis to break down fat molecules obtained from the extracted lipid, followed by three additional independent processes to further tune the phase change properties of PCMs. The esterification significantly decreases the phase transition temperatures while slightly improving latent heat; the UV-crosslinking moderately raises both the phase transition temperature and latent heat; the crystallization remarkably increases the both. The future research and guidelines are discussed to develop the large scale manufacturing with cost effectiveness, to optimize synthesis process by multiscale modeling, and to improve thermal conductivity and latent heat capacities at the same time. [ABSTRACT FROM AUTHOR]

In order to explore the influence of laser power on the evolution of molten pool and convective heat transfer of laser cladding Incoloy 926 on stainless steel surface, a three-dimensional thermal fluid multi-field coupled laser cladding numerical model was established in this paper. The variation of latent heat during solid-liquid phase transformation was treated by apparent heat capacity method. The change in the gas–liquid interface was tracked using the mesh growth method in real time. The instantaneous evolution of temperature field and velocity flow field of laser cladding Incoloy 926 on a stainless steel surface under different laser power was discussed. The solidification characteristic parameters of the cladding layer were calculated based on the temperature-time variation curves at different nodes. The mechanism of the impact of laser power on the microstructure of the cladding layer was revealed. The experiment of laser cladding Incoloy 926 on 316L surface was carried out under different laser power. Combined with the numerical simulation results, the effects of laser power on the geometrical morphology, microstructure and element distribution of the cladding layer were compared and analyzed. The results show that with the increase in laser power, the peak temperature and flow velocity of the molten pool surface both increase significantly. The thermal influence of the molten pool center on the edge is enhanced. The temperature gradient, solidification rate, and cooling rate increased gradually. The microstructure parameters (G/R) are relatively small when the laser power is 1000 W. In the experimental range, the dilution rate and wetting angle of the cladding layer both increase with the increase in laser power. When the laser power is 1000 W, the alloying elements of the cladding layer are more evenly distributed and the microstructure is finer. The experimental results are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Landfast sea ice plays a crucial role in the Antarctic coastal ecosystem and iceberg dynamics. This study employs a single-column thermodynamic model to simulate landfst sea ice near Zhongshan Station from 2016 to 2017. Forcing variables, including wind, temperature, specific humidity, and radiation, were obtained from in-situ automatic weather stations (AWS) and reanalysis atmospheric data (ERA5 and JRA55). Although there was alignment with observations, reanalysis data consistently overestimated precipitation, with a correlation coefficient of less than 0.8. Sensitivity experiments were conducted by varying precipitation inputs. In Group 1, the simulated sea ice thickness showed minimal biases of 6.3 cm and 5.3 cm when using AWS and ERA5 data, respectively. Additionally, the sea ice temperature simulations in Group 1 were within 0.3 ℃ of the observed values. The minimum bias in simulated sea ice thickness using JRA55 across all experiments was 10.9 cm. Overestimated snow depth, particularly with JRA55 data, resulted in thicker snow ice. Excessive precipitation led to overestimated snow depth, which revealed the dual impact of snow. Excessive snow depth led to greater snow ice formation, while reduced snow depth resulted in colder inner sea ice temperatures, promoting more bottom sea ice growth. Bottom melt primarily reduced sea ice thickness, while lateral melt reduced sea ice fraction, with latent heat flux dominating energy loss during melting. This study underscores the significance of snow depth, largely influenced by precipitation, in understanding the ablation process of landfast sea ice. Despite the discrepancies between simulations and observations, which indicate a need for refinement, this study highlights the potential of reanalysis data in sea ice thermodynamic simulations. [ABSTRACT FROM AUTHOR]

Before establishment of the Asian summer monsoon, the spring diabatic heating over the Tibetan Plateau (TP) is regarded as an essential factor to modulate rainfall in the surrounding and downstream regions of the TP, but its intraseasonal variability (ISV) has not been paid enough attention to. Based on the observation and ERA5 reanalysis data, the first two leading modes of the spring ISV of the surface sensible heat (SH) and the latent heat of condensation (LH) over the eastern TP have been identified, which both exhibit a north–south dipole and uniform pattern with dominant ~ 40-day and 10–20-day periods, respectively. The ISV of LH is strongly negatively correlated to that of SH, which is determined by variations of ground-air temperature difference. The north–south dipole patterns for the 40-day period are induced by the synergistic effect of northward-propagating circulation anomalies from the tropical Indian Ocean and a southeastward-propagating wave train in the middle-to-high latitudes, whereas the uniform patterns can be attributed to an eastward-propagating zonal wave train in the mid-latitude. Accompanied with the ISV of SH and LH, the anomalous moisture convergence/divergence and thus rainfall anomalies occur in the Yangtze River Basin. These results suggest that the spring diabatic heating over the eastern TP has great potentials as a predictability source of anomalous precipitation in its downstream regions on intraseasonal timescale. [ABSTRACT FROM AUTHOR]

The impacts of hydrometeor-related processes on the development and evolution of the "21·7" extremely heavy rainfall in Zhengzhou were investigated using WRF simulations. Surface precipitation was determined by the hydrometeor microphysical processes (all microphysical source sink terms of hydrometeors) and macrophysical processes (local change and flux convergence of hydrometeors). The contribution of hydrometeor macrophysical processes was commonly less than 10%, but could reach 30%–50% in the early stage of precipitation, which was largely dependent on the size of the study area. The macrophysical processes of liquid-phase hydrometeors always presented a promotional effect on rainfall, while the ice-phase hydrometeors played a negative role in the middle and later stages of precipitation. The distributions of microphysical latent heat corresponded well with those of buoyancy and vertical velocity (tendency), indicating that the phase-change heating was the major driver for convective development. Reasonable diagnostic buoyancy was obtained by choosing an area close to the convective size for getting the reference state of air. In addition, a new dynamic equilibrium involving hydrometeors with a tilted airflow was formed during the heavy precipitation period (updraft was not the strongest). The heaviest instantaneous precipitation was mainly produced by the warm-rain processes. Sensitivity experiments further pointed out that the uncertainty of latent heat parameterization (±20%) did not significantly affect the convective rainfall. While when the phase-change heating only altered the temperature tendency, its impact on precipitation was remarkable. The results of this study help to deepen our understanding of heavy rainfall mechanisms from the perspective of hydrometeor processes. [ABSTRACT FROM AUTHOR]

This study aimed to determine a method to suppress thermal runaway in electric vehicles by passing water directly inside the battery case. A scaled-down model experiment was conducted using a lithium-ion battery pack consisting of six 18650 cells, which is equal to about one-thousandth of an electric vehicle's charging capacity. The heat generation rate, heat transfer coefficient, and time constant for cooling were measured using a simple model for the cooling methods, thermal runaway stages, and state of charge. When thermal runaway occurred during natural cooling, the battery temperature rose to 630 °C at a rate of 116 °C/s. Through water injection, the thermal runaway was quickly suppressed with a time constant of about 3 s and a heat transfer coefficient of 3400 W/m2·K. The water effectively prevented chain explosions and kept harmful gases emitted from the batteries. It was found that it is difficult to completely suppress thermal runaway using the latent heat of the stagnant water in the spaces between cylindrical batteries. If the experimental results of this study were to be applied to an actual vehicle, it is expected that thermal runaway could be suppressed with a time constant of about 170 s and 1 ton of water. [ABSTRACT FROM AUTHOR]

The earthquake (EQ) precursors from satellites data portray an image of the energy propagation from the lithosphere to atmosphere and then to the ionosphere. Previous studies have often presented detailed discussion on different precursors at various altitudes. However, this study aimed to investigate the anomalies at various altitudes associated with the Hotan China EQ (hypocentral depth: 10 km, latitude 35.5°N, longitude 82.4°E). The goal was to identify pre-and post-seismic anomalies statistically in the conjunction with the wavelet transformation. We observed possible precursors in the atmosphere such as variations in aerosol optical depth, tropopause pressure, relative humidity, latent heat flux, and outgoing longwave radiation in a window of 5–10 days before the seismic event. Moreover, the total electron content had precursors during quiet geomagnetic storm conditions (−20 < Dst ≤ − 40 nT, Kp ≤ 3) beyond the bound within 5–10 days. These findings highlight the potential of using atmospheric and ionospheric parameters to detect seismic anomalies as EQ precursors for improved EQ early warning systems. [ABSTRACT FROM AUTHOR]

Flash droughts, characterised by their rapid onset and significant impacts on local communities and agriculture, pose challenges for monitoring and mitigation efforts due to their unpredictable nature. Therefore, this study aims to investigate the occurrence, characteristics and influencing factors of flash droughts in the Ganga River Basin (GRB) for the period 1981–2020. Flash droughts are identified using the pentad averaged root zone soil moisture (PRZSM). The Mann‐Kendall trend test is used to determine the spatial and temporal pattern of flash drought characteristics. Furthermore, a multivariate flash drought index (MFDI) is developed to account for the combined effects of flash drought characteristics. Finally, wavelet coherence analysis evaluates the relationship between climatic oscillations and MFDI at the sub‐basin scale. Utilising a revised flash drought identification approach incorporating non‐stationary cumulative distribution functions (CDFs), the study identifies flash droughts in the GRB, particularly emphasising higher occurrences in the Chambal and Upper Yamuna Sub‐basins. Analysis of flash drought characteristics under stationary and non‐stationary conditions reveals increased frequency, severity and decline rates, highlighting the impact of evaporation and latent heat flux. Furthermore, the Upper Ganga Sub‐basin demonstrates coherence with the DMI at shorter time scales (1 to 4‐year time scales), while the Lower Ganga Sub‐basin displays a pronounced association with the NINO3.4 index (5.65‐year time scale), indicating the impact of climate oscillations on flash drought dynamics in these regions. These findings provide valuable insights for drought monitoring, prediction and management strategies in a changing climate, emphasising the need for integrated approaches to address the complex interplay between climate variability and flash drought occurrences in the GRB. [ABSTRACT FROM AUTHOR]

This study examined Baltic Sea Marine Heatwaves (MHWs) using 42 years of satellite-derived sea surface temperature (SST) data. We found that MHWs in warmer months are more intense but shorter compared to MHWs in cooler months. Also, MHWs predominantly affect offshore areas in warmer months, whereas MHWs predominantly impacting coastal seas in cooler months, especially along the eastern coast. Our analysis of interannual variability revealed that, unlike in many other basins worldwide, Baltic MHWs tend to maintain a constant intensity, while their spatial extent has significantly increased over the last few decades. Shortwave radiation notably influences MHW intensity and spatial extent, with additional impacts from longwave radiation in cooler months and latent heat flux in warmer months. Northern Hemisphere teleconnections exhibit stronger correlations with MHWs in the Baltic Sea compared to global-scale climate oscillations, with the Eastern Atlantic pattern having a particularly significant effect on MHW variability in the region. [ABSTRACT FROM AUTHOR]

In this study, the impact of phase-change microcapsules (PCM) on asphalt performance was investigated through a series of orthogonal experiments. These experiments focus on the evaluation of the effect of the urea-formaldehyde (melamine-urea-formaldehyde) resin as a shell material and w-tetradecane as a core material on the synthetic efficiency of PCM. The optimal preparation process for PCM was analyzed. Differential scanning calorimetry and dynamic shear rheology were employed to assess the performance of the PCM-modified asphalt (referring to as phase change bitumen). The findings indicated that the most effective synthetic parameters were determined for PCM at an emulsifier concentration of 7 wt. %, an emulsification speed of 2 000 r/min, a mass ratio of core to wall material of 1:1, a 1: 7 oil-to-water volume ratio, a synthetic time of 90 min, and a reaction temperature of 80 °C. Under such conditions, PCM exhibited a latent heat of 117 J/g. Furthermore, the microcapsule shell presented excellent sealing properties, ensuring the stability of asphalt within the range required for construction temperature. The PCM-modified asphalt showed an exothermic interval from -7. 1 to -17. 9 °C and an endothermic interval from 2. 3 to 13. 5 °C. The PCM-modified asphalt presented a phase-change enthalpy of 5. 1 J/g at a microcapsule concentration of 7 wt. %. More importantly, the incorporation of PCM effectively slowed down the hardening process of the PCM-modified asphalt and maintained its stability at room temperature. The developed phase-change asphalt exhibits great potential for application. [ABSTRACT FROM AUTHOR]

The mid‐latitude extreme weather disasters are often associated with explosively developing cyclones (ECs). Based on different vertical development characteristics, 4,608 ECs identified over the North Pacific in the cold season of 44 years of NCEP‐CFSR reanalyzes are divided into four types of upward development and four types of downward development categories. ECs with vertical upward (downward) development follow a northeastward (nearly eastward) path, mainly explosively developing over the Northwest Pacific (Asia continent and Pacific). Furthermore, utilizing the piecewise potential vorticity inversion method reveals the synergetic forcing of the turbulent heat transport and baroclinicity in the lower troposphere, the latent heat release in the middle levels, the upper‐level jet stream, and the downward intrusion of stratospheric potential vorticity on the ECs. Different configurations of these influences from the troposphere to the stratosphere result in the occurrences of eight types of ECs in the cold season over the North Pacific. Plain Language Summary: Since the late twentieth century, there has been a significant variation in the frequency of explosively developing cyclones (ECs), which bring extreme weather disasters to the mid‐latitudes. This study classifies winter North Pacific ECs into four upward and four downward developing categories. The upward developing ECs include those enhanced only in the lower troposphere (UL‐EC), those developing upward to the middle troposphere (UM‐EC), those developing upward to the upper troposphere (UU‐EC), and those developing upward into the stratosphere (US‐EC). In contrast, the downward developing ECs can be classified as those intensifying only in the upper troposphere (DU‐EC), those developing downward to the middle troposphere (DM‐EC), those developing downward to the lower troposphere (DL‐EC), and those developing downward from the stratosphere (DS‐EC) to the lower troposphere. Furthermore, the piecewise potential vorticity inversion results show that the explosive development of UL‐EC and UM‐EC are dominated by the thermodynamical processes in the middle‐to‐lower troposphere, exhibiting a baroclinic structure with opposite anomalous geopotential height between the troposphere and stratosphere. However, the other types have a consistent stratospheric‐to‐tropospheric negative anomalies, which is determined by the upper‐layer dynamical processes. The downward intrusion of stratospheric potential vorticity dominates the explosive development for the US‐EC and DS‐EC. Key Points: The North Pacific explosively developing cyclones during cold season are divided into eight up‐ and down‐ward vertically developing typesThe explosively developing cyclones are proved to be an important link between the stratosphere and troposphere in the mid‐high latitudesUsing the piecewise potential vorticity inversion method, the quantitative forcings on the explosively developing cyclones are explored [ABSTRACT FROM AUTHOR]

The globally averaged diurnal temperature range (DTR) has shrunk since the mid‐20th century, and climate models project further shrinking. Observations indicate a slowdown or reversal of this trend in recent decades. Here, we show that DTR has a minimum for average temperatures close to 0°C. Observed DTR shrinks strongly at colder temperature, where warming shifts the average temperature toward the DTR minimum, and expands at warmer temperature, where warming shifts the average temperature away from the DTR minimum. Most, but not all climate models reproduce the minimum DTR close to average temperatures of 0°C and a stronger DTR shrinking at colder temperature. In models that reproduce the DTR minimum, DTR shrinking slows down significantly in recent decades. Models project that the global‐mean DTR will shrink over the 21st century, and models with a DTR minimum close to 0°C project slower shrinking than other models. Plain Language Summary: The diurnal temperature range, that is, the difference between daily maximum and minimum temperatures, affects both human health and plant development. Global data sets have shown a shrinking diurnal temperature range since the 1950s, but a recent study found that the diurnal temperature range had expanded again. In this study, we investigate how the diurnal temperature range behaves at different mean temperatures. We find that the diurnal temperature range is particularly small for temperatures close to the melting point of water (0°C), and larger for both colder and warmer temperatures. Due to the latent heat of freezing/melting, more energy is required to warm the soil from −1 to +1°C than from −3 to −1°C or from 1 to 3°C. The diurnal temperature range shrinks in regions and seasons with negative average temperature, where global warming pushes the average closer to 0°C and expands for warmer temperature. Most, but not all climate models also show a narrow diurnal temperature range near 0°C, shrinking of the temperature range at colder temperature and a slower reduction in the diurnal temperature range in recent decades. Models suggest that the currently observed expansion of the diurnal temperature range is a transient phenomenon. Key Points: The diurnal temperature range (DTR) has a local minimum near average temperatures of 0°CDTR in observations shrinks strongly for average temperatures below 0°C and expands for warmer temperaturesClimate models that reproduce the local DTR minimum near 0°C show a significant slowdown of DTR shrinking in recent decades [ABSTRACT FROM AUTHOR]

The parameterizations of air‐sea turbulent heat flux are one of the major bottlenecks in atmosphere‐ocean coupled model development, which play a crucial role in sea surface temperature (SST) prediction. Recently, neural networks start to be applied for the development of parameterizations of interface turbulent heat flux. However, these new parameterizations are primairily developed for specific regions and have not been tested in real atmosphere‐ocean coupled models. In this study, we propose a new air‐sea heat flux parameterization using a physical‐informed neural network (PINN) based on multiple observational data sets worldwide. Evaluated with an independent observation data set, it is shown that the PINN can significantly reduce the RMSE of latent heat flux by at least about 48.6% compared to three traditional bulk formulas. Moreover, the PINN can be flexibly updated with new observational data by transfer learning. To test the performance of the new parameterization in realistic application, we implement the PINN into a global ocean‐atmosphere coupled model and make seasonal forecasts for the first time. The PINN markedly reduce the errors of equatorial SST forecast, indicating a good performance of the PINN‐based air‐sea turbulent heat flux scheme. Noticeably, due to limited observational data, the NN‐based parameterizations tend to underestimate heat flux at high wind speeds compared with bulk formula‐based parameterizations. With more data available at extreme conditions, the PINN can be improved via transfer learning and need to be futher evaluated. This study suggests that PINN‐based air‐sea heat flux parameterization is promising to improve SST simulation. Plain Language Summary: The air‐sea turbulent heat flux plays a crucial role in advancing marine science and is the key to improving the accuracy of the sea surface temperature (SST) prediction. The traditional parameterizations for air‐sea turbulent heat flux have large deviations in some circumstances and are hard to update since they are developed based on unique observation datasets. The emergence of artificial intelligence offers a fresh avenue to address this issue. In this study, we develop air‐sea heat flux parameterization based on a PINN and multiple observational data sets, which measured air‐sea heat fluxes directly. Our novel parameterization outperforms three bulk formula‐based parameterizations in offline tests and solves the problem of unphysical result of neural networks. The new parameterization also shows great potential in improving the accuracy of SST prediction in multiple online tests. Key Points: We propose a new air‐sea turbulent heat flux parameterization based on physical‐informed neural network (PINN) which is trained on data in situThe new scheme can accurately calculate the air‐sea turbulent heat flux and perform well in a global seasonal forecastThe PINN can be flexibly updated with new observational data by transfer learning [ABSTRACT FROM AUTHOR]

The eastward displacement of Southwest Vortices (SWVs) profoundly impacts the precipitation in the middle and lower reaches of the Yangtze River Basin (YRB) in summer. At present, the feedback mechanism of latent heating on the persistent eastward movement of SWVs under the influence of the orographic effect of the second‐step terrain in China remains unclear. Therefore, this study focused on clarifying the relationship between orographic effects and the mechanisms governing the persistent eastward movements of SWVs, as well as the feedback effect of latent heating on the eastward‐moving SWVs. In this study, it is revealed that discontinuous maintenance of closed vortex circulation occurs when eastward‐moving SWVs pass over the second‐step terrain region. Specifically, eastward‐moving SWVs first experience dissolution on the windward side, followed by substantial reconstruction of closed vortex circulation on the leeward side when passing over the second‐step terrain region. Moreover, the reconstruction of closed vortex circulation on the leeward side is closely associated with the feedback effect of latent heating, and the microphysical property of cold clouds identified during the vortex intensification determines the dual‐peak feature observed in the vertical constitution of the total latent heating, which is related to two major phase‐transition processes: the condensation of water vapor into liquid‐phase hydrometeors (LCP_vapor) process and the desublimation of water vapor into ice‐phase hydrometeors (LSP_vapor) process. From a potential vorticity (PV) perspective, latent heating promotes the genesis of PV anomalies, which accordingly facilitates the maintenance of a positive "vorticity tower" (i.e., total budget of vorticity) via the tilting effect and the horizontal advection effect of local vorticity. Further sensitivity experiments of latent heating indicated that latent heating associated with the LCP_vapor process fulfills a more important role in sustaining the positive "vorticity tower" than does that associated with the LSP_vapor process during the vortex intensification. Plain Language Summary: This study focused on clarifying the relationship between the orographic effect of the second‐step terrain and the vertical distribution of latent heating, as well as unraveling the feedback mechanism of latent heating on the intensification of vortices downstream of the second‐step terrain. The microphysical properties of cold clouds are further highlighted during the intensification of vortices, and the vertical profile of latent heating exhibits double‐peak features correspondingly. This is associated with two categories of phase‐transition processes: the condensation of water vapor into liquid‐phase hydrometeors (i.e., LCP_vapor) and the desublimation of water vapor into ice‐phase hydrometeors (i.e., LSP_vapor). Further analysis confirms that the topographically enhanced convection downstream of the second‐step terrain provides favorable dynamic conditions for further vertical transportation of water vapor, which substantially facilitates the LCP_vapor and LSP_vapor processes. Latent heating is conducive to the genesis of PV anomalies and facilitates the maintenance of a positive "vorticity tower" via the tilting effect and the horizontal advection effect of local vorticity, which plays crucial roles in strengthening vortices. Key Points: The evolution of vortices indicates the closed vortices is not a continuous maintenance process during the eastward propagation of the SWVsA causal relationship is established between the orographic effect of the second‐step terrain and the latent heating via convectionThe condensation process of water vapor plays the most decisive role in affecting the feedback effect of latent heating [ABSTRACT FROM AUTHOR]

Phase‐change materials (PCMs) have become a hot spot in the development of modern thermal management materials because of their absorbing and releasing heat while keeping the temperature constant during phase change process. However, their relatively low thermal conductivity (TC) considerably restricts their further application. In this work, graphene nanosheets (GNS) were initially nickel‐plated to increase the contact area between adjacent GNS (in the form of Ni@GNS) by constructing a "point‐surface" structure. Then, the prepared Ni@GNS was coated with polydopamine (PDA) to prepare PDA‐Ni@GNS, which helped to effectively reduce the interface thermal resistance (ITR) between the filler and the matrix, and also made the prepared filler more easily dispersed in the polymer matrix. By constructing well‐defined three‐dimensional (3D) thermally conductive pathways in the matrix, the PCMs exhibited excellent TC and effectively prevented the leakage of polyethylene glycol (PEG) even at low filler loading. The results of thermogravimetry (TG), differential scanning calorimeter (DSC), and cyclic DSC tests jointly showed that the PDA‐Ni@GNS/CNF‐C/SA/PEG PCMs displayed excellent thermal storage properties, high latent heat as well as good cyclic thermal stability. The present study provides a facile way of preparing PEG‐based PCMs, which are applicable in thermal management area. [ABSTRACT FROM AUTHOR]

Phase change materials (PCM) often encounter severe problems of leakage and shape collapse concerns. Chemical modification methods, utilizing chemical bonds to bind phase change molecular chains, have the potential to address the above‐mentioned problems radically. However, this approach often entails the use of expensive raw materials and complex processes. Therefore, a simple one‐pot preparation method had been reported using earth‐abundant and inexpensive octadecyl methacrylate (OMA) and 1,6‐hexanediol diacrylate (HD) as raw materials to prepare PCM with a molecular structure of cross‐linked polymer main chains and phase change side chains through free radical polymerization. Owing to the three‐dimensional polymer main chain structure, it exhibited excellent leakage‐proof performance, maintaining its form‐stable nature at 70°C with no obvious leakage observed during the phase change process, confirming it to be an excellent intrinsic solid–solid PCM (SSPCM). Additionally, the introduction of the cross linking segment significantly improves its thermal stability, and the 50% degradation temperature increased significantly from 228.8 to 355.9°C. Moreover, the latent heat increased with the decrease of the crosslinking density until the molar ratio of HD/OMA was reduced to 1/40 and then tended to reach constant. At the optimal ratio the latent heat of SSPCM can reach 88.23 J g−1. Excessive crosslinking density will affect the stacking tightness of molecular chains during the crystallization process, thereby reducing the latent heat. [ABSTRACT FROM AUTHOR]

Tropical oceans are the main global water vapor and latent heat sources, but their responses to radiative forcing remain unclear. Here, we investigate oceanic moisture dynamics of the western tropical Pacific (WTP) over the past 210,000 years through an approach of planktonic foraminiferal triple oxygen isotope (Δ′17O). The Δ′17O record is dominated by the precession cycles (~23,000 years), with lower values reflecting higher humidity in concert with higher Northern Hemisphere summer insolation. Our empirical and modeling results, combined with other geological archives, suggest that the enhanced moisture convergence over the WTP largely intensifies changes in the meridional and zonal hydrological cycles, affecting rainfall patterns in East Asia and northern South America. We propose that the insolation-driven WTP moisture dynamics play a pivotal role in regulating tropical hydroclimate. [ABSTRACT FROM AUTHOR]

AbstractPhase change energy storage materials are the core of phase change energy storage technology. Phase change hysteresis can cause phase change materials not to store and release thermal energy as expected, and most studies have not focused on this. A low-temperature eutectic phase change material CaCl2·6H2O–MgCl2·6H2Omaterial prepared was investigated, and some influencing factors of the phase change hysteresis phenomenon and its regular characteristics were aspired to be obtained. The melting-solidification curves were obtained using a step-cooling test bench, and the latent heat values and heat absorption and exothermic curves of materials with different proportions were measured by a differential scanning calorimeter. The experimental results show that the temperature difference of the phase change hysteresis tended to increase gradually with the increase of the mass fraction of the nucleating agent, and the hysteresis temperature difference increases from the initial 3.9 °C–15.02 °C when SrCl2·6H2O was added by 2.4%. The temperature difference of the phase change hysteresis increased gradually with the increase of the mass fraction of the thickener. This paper provides a new idea for optimizing the properties of phase change energy storage materials and provides a possibility for realizing the parametric control of phase change hysteresis factors. [ABSTRACT FROM AUTHOR]

Turning the dirt, we have cultivated back into soil is critical to securing our planetary future. The world’s principal existential challenges – food, water and energy security, climate change abatement, biodiversity protection and human health1 – are all underpinned by soil dysfunction. Yet, little is known about soil function, soil services and threats to soil, or how the state of our soils, determined by land use and land management, cause desertification and climate change. As greenhouse gases are transparent to incoming solar radiation, we must mitigate excess atmospheric heat by reducing the amount of organic matter mined from the soil, because when the sun’s rays fall on exposed, drained, baked dry soil, most of the solar radiation is converted from latent heat to sensible heat. Soil specific policy and legislation must be developed to regulate sources of excess sensible heat, consistent with limiting global temperature rise to 1.5°C above pre-industrial levels. Through soil security, we can deliver a better present and safeguard our planetary future. [ABSTRACT FROM AUTHOR]

The influence of greenhouse warming on mesoscale air-sea interactions, crucial for modulating ocean circulation and climate variability, remains largely unexplored due to the limited resolution of current climate models. Additionally, there is a lack of theoretical frameworks for assessing changes in mesoscale coupling due to warming. Here, we address these gaps by analyzing eddy-resolving high-resolution climate simulations and observations, focusing on the mesoscale thermal interaction dominated by mesoscale sea surface temperature (SST) and latent heat flux (LHF) coupling in winter. Our findings reveal a consistent increase in mesoscale SST-LHF coupling in the major western boundary current regions under warming, characterized by a heightened nonlinearity between warm and cold eddies and a more pronounced enhancement in the northern hemisphere. To understand the dynamics, we develop a theoretical framework that links mesoscale thermal coupling changes to large-scale factors, which indicates that the projected changes are collectively determined by historical background wind, SST, and the rate of SST warming. Among these factors, the large-scale SST and its warming rate are the primary drivers of hemispheric asymmetry in mesoscale coupling intensification. This study introduces a simplified approach for assessing the projected mesoscale thermal coupling changes in a warming world. This study shows that greenhouse warming intensifies mesoscale thermal coupling in western boundary currents, primarily driven by large-scale sea surface temperature and its warming rate, with key implications for ocean circulation and climate variability. [ABSTRACT FROM AUTHOR]

The observational data of the air-sea interface and upper ocean elements from a buoy array deployed in the northern South China Sea from June to November 2014 is analyzed. The COARE 3.0 algorithm was adopted to examine the variability of air-sea heat fluxes and their contributions to near-surface ocean temperature changes. During the observation period, air-sea heat exchange in the northern South China Sea is primarily determined by solar shortwave radiation and latent heat flux, with net heat flux mostly negative, indicating that the ocean predominantly loses heat. In autumn, net heat flux loss significantly increased by an average of 34.4 W/m2, primarily due to enhanced latent heat loss driven by stronger winter monsoon. During typhoon period, net air-sea heat flux was significantly suppressed, mainly due to reduced solar shortwave radiation, with minimal contribution from sensible heat flux. Near-surface ocean temperature exhibited a seasonal cooling trend, averaging 29.7°C in summer and 28.4°C in autumn. The maximum cooling during typhoon reached 3.1°C, with minimal contribution from air-sea heat flux. During the monsoon transition period, weaker winds led to a slight increase in near-surface ocean temperature, with air-sea heat flux contributing 70.2% and 56.3% to this process. During winter monsoon, more uniform water column mixing resulted in a gradual decrease in near-surface ocean temperature, with air-sea heat flux contributing over 60% to this process. [ABSTRACT FROM AUTHOR]

In recent years, there has been a rise in human activities in oceanic areas, making the land–atmosphere interactions over islands a major scientific concern on a global scale. Examining the observation data from offshore areas enables a more comprehensive understanding of the turbulent fluxes in offshore atmospheric environments, patterns of momentum, energy and material exchange between the atmosphere and underlying surface in an oceanic boundary layer, and development of a heterogeneous atmospheric boundary layer. The related findings will assist in developing theoretical models and parameterization schemes to simulate the influence of heterogeneous surfaces on land–atmosphere interactions on the South China Sea Islands. Existing studies on the turbulent fluxes over the South China Sea Islands were mainly conducted on the Nansha Islands, whereas studies on the waters of the South China Sea are scarce. In this study, we used 10 Hz high‐frequency turbulence measurements to calculate the latent and sensible heat fluxes over the South China Sea Islands using the eddy correlation method. These findings were then compared with data from the Dunhuang Gobi, Ordos desert, and Xilingol grassland regions in inland China, along with the observed net radiation and surface heat fluxes. The findings indicate that the energy fluxes over the South China Sea in summer exhibit prominent diurnal variations. The magnitude of either latent or soil heat flux is low, and the net radiation is predominantly transformed into sensible heat flux, which warms the atmosphere. Furthermore, the daily variation curves of sensible and latent heat fluxes are influenced by intermittent turbulence on the islands and reefs, resulting in a less smooth pattern compared with soil heat flux. Although the South China Sea Islands have small land areas and are surrounded by the sea, the land–atmosphere interactions over the underlying surface of this region are similar to those over the underlying surface of grasslands in inland China during summer. The daily mean sensible heat flux on the islands is higher than that in an inland area, and the time lag in its response to sunrise is longer than that in inland areas by approximately 1 h. The overall energy balance ratio is approximately 0.75, c which is in line with the average level, but an energy balance residual of approximately 25% still exists. Furthermore, extreme weather conditions, such as typhoons, can disrupt the diurnal variations of sensible and latent heat fluxes, and the cyclical patterns are subsequently restored. [ABSTRACT FROM AUTHOR]

Surface thermal inertia derived from satellite imagery offers a valuable tool for remotely mapping the physical structure and water content of planetary regolith. Efforts to quantify thermal inertia using surface temperatures on Earth, however, have consistently yielded large uncertainties and suffered from a lack of reproducibility. Unlike dry or airless bodies, Earth's abundant water and dense atmosphere lead to dynamic thermophysical conditions that are a greater challenge to model than on a world like Mars. In this work, an approach was developed using field experiments to inform and fine‐tune a thermophysical model of terrestrial sediment and calculate an inherent thermal inertia value with higher precision and less initial knowledge of the sediment than has previously been achieved remotely on Earth. A thermal inertia derived for a basaltic tephra site in Northern Arizona was replicated within 1% between different field seasons, demonstrating reproducibility. Model‐derived values were validated in situ by two different thermophysical field probes to within 8% of the measured mean values. Analog studies such as this hold the promise of improved interpretations of surface materials on Mars, and an accurate thermal model for Earth is the key step to enabling translation between the two worlds. Key Points: This work introduces a new approach for relating remote temperature observations to regolith physical propertiesThe manuscript details the development, calibration, and testing of a soil‐agnostic thermophysical model for application to Earth and MarsSoil moisture and temperature have dynamic effects on thermal conductivity and latent heat that depend on regolith type [ABSTRACT FROM AUTHOR]

Wind gustiness is an effective approach for addressing mesoscale enhancement in estimating air-sea interface fluxes. In this study, an improved convective gustiness parameterization scheme based on convective available potential energy (CAPE) is formulated utilizing reanalysis data and wind observations from moored buoys. This new parameterization was examined by implementing it in the air-sea flux transfer scheme within the National Center for Atmospheric Research Community Earth System Model (NCAR CESM) version 2.1.3 and contrasting it with a previously proposed scheme based on convective precipitation rate. The results indicate a significant reduction in negative biases of surface winds and latent heat fluxes over the tropical Indian Ocean and western Pacific during summer with the implementation of either gustiness scheme, resulting in an average increase in latent heat flux of approximately 9 W·m− 2. Specifically, the CAPE-based scheme shows a more favorable impact in the Indo-Pacific Warm Pool region, whereas the precipitation-based scheme exhibits inferior performance in the western Pacific Intertropical Convergence Zone. Further analysis reveals that the inclusion of the gustiness scheme distinctly alters surface evaporation and latent heat flux, influencing vertical motion in the area with active convective activity and effectively improving precipitation simulations by up to 18%. Moreover, the CAPE-based scheme reduces the bias in summer precipitation simulations by approximately 5% more than the precipitation-based scheme. [ABSTRACT FROM AUTHOR]

Investigating the impact of El Niño-Southern Oscillation (ENSO) on subtropical Indian Ocean dipole (SIOD) facilitates understanding their combined effects on African and Australian climate. We found the correlation between ENSO in austral summer and SIOD in following autumn is enhanced after the early 1990s. Before the early 1990s, ENSO only changes the southeastern Indian Ocean (SEIO) temperature by modulating the Walker circulation. In contrast, after the early 1990s, El Niño induces positive sea surface temperature (SST) anomalies in the SEIO and negative SST anomalies in the southwestern Indian Ocean (SWIO), causing the enhanced ENSO-SIOD correlation. This increasing influence of ENSO on the SWIO closely links to the ENSO-related atmospheric teleconnection in the midlatitude Southern Hemisphere (SH). Before the early 1990s, the El Niño-related teleconnection coincides with a low-pressure anomaly to the south of southern Africa. Anomalous westerlies on the northern flank of this low-pressure warm the SWIO SST by increasing the solar radiation and reducing the mixed-layer thickness but cool the SWIO SST by changing the oceanic heat advection. These opposite effects cause a weak ENSO-SWIO connection. After the early 1990s, the low-pressure related to El Niño shifts to the SWIO in January–February–March, causing anomalous local moisture divergence. The increased air–sea humidity difference enhances the latent heat release and then deepens the mixed-layer thickness, cooling the SWIO SST. The interdecadal differences in the ENSO-related SH teleconnection are probably attributed to the westward-shifted ENSO pattern and the reduced response of the Tasman Sea SST to ENSO after the early 1990s. [ABSTRACT FROM AUTHOR]

The Asian Summer Monsoon Anticyclone (ASMA) is a gateway for atmospheric pollutants transported to the upper troposphere and lower stratosphere (UTLS). Thus, it is necessary to understand the relative roles of vertical transport due to convection and horizontal transport due to advection in the formation and sustenance of the ASMA. Outgoing longwave radiation reveals that the ASMA region shows characteristic features associated with strong convective activity in its eastern (70°–120° E) part while subsidence dominates in the western (20°–70° E) part. Over the convective region, the convergence of latent heat flux extends from the Indian mainland (65°–110° E) to the west Pacific Warm Pool (WP) (110°–160° E). On average the ASMA region is characterized by a main convective outflow level at ~ 9 km. This level varies considerably with longitude being higher (~ 10.5 km) over the convective region and lower (~ 7 km) over the subsidence region. Furthermore, the mean convective outflow level is higher over the WP (11.5 km) region when compared to the Indian mainland (10 km) region. From the thermodynamic energy equation, we have calculated the convective and advective terms and found anomalously cold advection over the subsidence region and warm advection over the convective region. The warm advection over the convective region is split into two parts with the stronger one located over the Indian region and the weaker one over the WP region. Similarly, stronger convection occurs over the Indian mainland (convective term ~ 4 K/day) compared to the WP (~ 1 K/day). The cold advection over the subsidence region is mainly centered near 30° E longitude. The convection over the Indian region and the cold advection over the subsidence region as well as warm advection and convection over the WP region are associated. We find that the advective terms change in magnitude and shift together with the convective terms in response to signals of the El Nino Southern Oscillation and the Indian Ocean Dipole. [ABSTRACT FROM AUTHOR]

Climate models are useful tools for monthly to decadal prediction of the evolution of climate. This study assesses how CMIP6 models represent soil moisture-latent heat regimes and coupling processes between the land and atmosphere. Metrics considered are terrestrial and atmospheric coupling indices to show the nature and strength of the coupling over Africa, focusing on the March to May (MAM) and June to August (JJA) seasons over East, Central, and West Africa. Characterization of the annual cycle indicates that model biases are highest during the peak of the rainfall season and least during the dry season, while soil moisture biases correspond with rainfall. Models show appreciable sensitivity to regional characteristics; there was model consensus in representing East Africa and the Sahel as regions of limited soil moisture, while major differences were noted in the wet regime over Central Africa. Most CMIP6 models tend to overestimate the strength of the terrestrial and atmospheric coupling pathways over East and Southern Africa. Inter-model differences in coupling indices could be traced to their inter-annual variability rather than the mean biases of the variables considered. These results encourage further advancement of land surface schemes in the next generation of climate models for a better representation of climate over Africa. [ABSTRACT FROM AUTHOR]