Surface Temperature Ts Research Articles

Microclimate analysis of Ganga riverfront in Patna: spatial form perspective

ABSTRACT The investigation in this research scrutinizes the influence of spatial form factors on thermal comfort along the Ganga riverfront trail during the spring season. Understanding how spatial form factors impact local climate parameters and PET values is crucial for optimizing thermal comfort in urban waterfronts. The research addresses the need to improve thermal comfort in rapidly urbanizing areas through strategic urban design. Data were collected from eight measurement points along the riverfront, analyzing Air Temperature (Ta), Relative Humidity (RH), Wind Velocity (v), Surface Temperature (Ts), Global Radiation (G) and Mean Radiant Temperature (Tmrt). The study employs a combination of field measurements and statistical analysis to assess the correlation between spatial form factors and thermal comfort indicators. Findings reveal that lower building height (Hb) values are associated with more favorable thermal comfort conditions, while higher Hb negatively impacts thermal comfort. The study also highlights that building spacing (ADb) influences thermal comfort, with findings contrasting those from composite climates, suggesting a need for context-specific design strategies. The research underscores the significant role of Ta and v in shaping Physiological Equivalent Temperature (PET), aligning with previous studies in diverse urban contexts. The results emphasize the critical impact of spatial form on microclimate and thermal comfort, informing urban design and planning to enhance livability along the Ganga riverfront. This study contributes to the field by providing empirical evidence and practical insights for developing thermally comfortable walking trails.

Assessing the spatial-temporal impacts of underlying surfaces on 3D thermal environment: A field study based on UAV vertical measurements

The composition of underlying surfaces has a significant impact on the thermal environment within urban canopies. Current research predominantly focuses on surface temperature (Ts) and near-surface air temperature (Ta) at the pedestrian scale. However, studies on the Spatial-temporal distribution characteristics of the three-dimensional (3D) thermal environment within urban canopies remain scarce. This study selected 7 typical underlying surfaces and investigated the Spatial-temporal distribution characteristics of Ts and vertical Ta from 1.5 to 200 m by using unmanned aerial vehicle (UAV) and fixed measurement techniques. The results indicated that the largest differences in 3D thermal environment characteristics across different underlying surfaces occurred at 14:00, with the smallest at 05:30. Each underlying surface exhibited distinct day-night variations in their impacts on the 3D thermal environment, with the water body showing significant day-night difference. The dense forest positively regulated the urban thermal environment, but at night, it slightly adversely effected the thermal environment at the pedestrian scale. The bare soil had the second most adverse effect on the 3D thermal environment during the day, following the impervious pavement; thus, exposure of the land should be minimized in urban environments. There was a significant positive correlation between Ts and Ta at different heights (P < 0.05). At 05:30, 14:00, and 21:00, the heights of vertical influence of Ts on Ta were 2 m, 50 m, and 32 m, respectively. These results provide important references for urban environmental managers to mitigate the 3D urban heat island (3D UHI).

A universal triangle method for evapotranspiration estimation with MODIS products and routine meteorological observations: Algorithm development and global validation

The surface temperature (Ts) and vegetation index (VI) triangle method is one of the most famous and widely applied methods for regional evapotranspiration (ET) estimation. However, no robust validation has been performed yet to evaluate its accuracy on a global scale, making its accuracy unclear when compared with other global ET models. The main reason behind it is that most traditional triangle models depend on the Ts-VI feature space within a certain spatial domain to parameterize their boundary conditions. The domain dependency makes it impossible to derive universal boundaries for continental or global application. Under this background, this study presented a universal triangle method for ET estimation with Moderate Resolution Imaging Spectroradiometer (MODIS) products and routine meteorological observations. The solution for boundary conditions was performed pixel by pixel without the consideration of spatial domain based configuration. Specifically, the dry boundary was solved theoretically based on the surface energy balance equation, and the wet boundary was substituted by wet-bulb temperature estimated from dew point temperature and air temperature. The validation against ground observations collected from 33 flux towers worldwide shows that this universal triangle method achieved evaporative fraction (EF) estimation with the correlation coefficient of 0.65, the mean absolute error of 0.17, the root-mean-square-error of 0.20, and the bias of 0.13. These four metrics of daily ET estimation were 0.83, 0.71 mm/d, 0.90 mm/d, and 0.41 mm/d, respectively. This analysis is the first comprehensive validation of the triangle method on a global scale. The comparison with early work suggests that our universal triangle method on a global scale has reached a comparable accuracy to traditional triangle models at regional scale. However, the universal triangle method has the capacity to monitor ET continuously pixel by pixel without domain dependency. This is just what most traditional triangle methods do not possess.

Urbanization Effect on Regional Thermal Environment and Its Mechanisms in Arid Zone Cities: A Case Study of Urumqi

Urumqi is located in the arid region of northwestern China, known for being one of the most delicate ecological environments and an area susceptible to climate change. The urbanization of Urumqi has progressed rapidly, yet there is a lack of research on the urbanization effect (UE) in Urumqi in terms of the regional climate. This study investigates the UE of Urumqi (urban built-up area) on the regional thermal environment and its mechanisms for the first time, based on the WRF (Weather Research and Forecasting) model (combined with the Urban Canopy Model, UCM) simulation data of 10 consecutive years (2012–2021). The results show that the UE on surface temperature (Ts) and air temperature at 2 m (T2m) is strong (weak) during the night (daytime) in all seasons, and the UE on these is largest (smallest) in spring (winter). In addition, the maximum UE on both Ts and T2m is present over southern Urumqi in winter, whereas the maximum UE is identified over the northern Urumqi in other seasons. The maximum UE on Ts occurred in northwestern Urumqi at 18 LST (Local Standard Time, i.e., UTC+6) in autumn (reaching 5.2 °C), and the maximum UE on T2m occurred in northern Urumqi at 4 LST in summer (reaching 2.6 °C). Urbanization showed a weak cooling effect during daytime in summer and winter, reflecting the unique characteristics of the UE in arid regions, which are different from those in humid regions. The maximum cooling of Ts occurred in northern Urumqi at 11 LST in summer (reaching −0.4 °C), while that of T2m occurred at 10 LST in northern and northwestern Urumqi in winter (reaching −0.25 °C), and the cooling effect lasted for a longer period of time in summer than in winter. The UE of Urumqi causes the increase of Ts mainly through the influence of net short-wave radiation and geothermal flux and causes the increase of T2m through the influence of sensible heat flux and net long-wave radiation. The UE on the land surface energy balance in Urumqi can be used to explain the seasonal variation and spatial differences of the UEs on the regional thermal environment and the underlying mechanism.

Contributions of Soil Moisture and Vegetation on Surface-Air Temperature Difference during the Rapid Warming Period

The difference (DIF) between land surface temperature (Ts) and near surface air temperature (Ta) is the key indicator of the energy budget of the land surface, which has a more complex process than the individual Ts or Ta. However, the spatiotemporal variations and influencing factors of DIF remain incomplete. The contribution of vegetation and soil moisture (SM) as key driving factors to DIF is not yet clear. Here, we analyzed the spatiotemporal variation patterns of DIF in China from 2011 to 2023 using in situ Ts and Ta data. A convergent cross-mapping method was employed to explore the causal relationship between SM, NDVI and DIF, and subsequently calculated the contribution of NDVI and SM variations to DIF under different climatic backgrounds. The results indicate that during the study period, DIF values were all above 0 °C and showed a significant increasing trend with a national mean slope of 0.02 °C/a. In general, vegetation and SM have a driving effect on DIF, with vegetation contributing more to DIF (0.11) than SM (0.08) under different surface properties. The background values of SM and temperature have a significant effect on the spatial and temporal distribution of DIF, as well as the correlation of vegetation and soil moisture to DIF. The study outcomes contribute to a better understanding of the coupling relationship between the land surface and atmosphere, which are also crucial for addressing climate change and ecological environmental management.

Effect of Uncertainty in Water Vapor Continuum Absorption on CO2 Forcing, Longwave Feedback, and Climate Sensitivity

AbstractWe investigate the effect of uncertainty in water vapor continuum absorption at terrestrial wavenumbers on CO2 forcing , longwave feedback λ, and climate sensitivity at surface temperatures Ts between 270 and 330 K. We calculate this uncertainty using a line‐by‐line radiative‐transfer model and a single‐column atmospheric model, assuming a moist‐adiabatic temperature lapse‐rate and 80% relative humidity in the troposphere, an isothermal stratosphere, and clear skies. Due to the lack of a comprehensive model of continuum uncertainty, we represent continuum uncertainty in two different idealized approaches: In the first, we assume that the total continuum absorption is constrained at reference conditions; in the second, we assume that the total continuum absorption is constrained for all atmospheres in our model. In both approaches, we decrease the self continuum by 10% and adjust the foreign continuum accordingly. We find that continuum uncertainty mainly affects through its effect on λ. In the first approach, continuum uncertainty mainly affects λ through a decrease in the total continuum absorption with Ts; in the second approach, continuum uncertainty affects λ through a vertical redistribution of continuum absorption. In both experiments, the effect of continuum uncertainty on is modest at Ts = 288 K (≈0.02 K) but substantial at Ts ≥ 300 K (up to 0.2 K), because at high Ts, the effects of decreasing the self continuum and increasing the foreign continuum have the same sign. These results highlight the importance of a correct partitioning between self and foreign continuum to accurately determine the temperature dependence of Earth's climate sensitivity.

BeO in epoxy composites as TIM for high-power LED packages

Beryllium oxide (BeO)-filled epoxy composite was prepared and used as a thermal interface material (TIM) in light-emitting diode (LED) packages. The filler percentages influenced on changing thermal and optical behaviour of LED at various driving currents. An improvement of 14.36% in thermal conductivity was recorded from that of neat epoxy. The lowest total thermal resistance of 10.75 K/W ( Rth) and rise in junction temperature ( Tj) of 3.1°C were recorded at 100 mA driving current for 50 wt-% BeO-filled TIM attached LED followed by an improved optical output and lowered correlated colour temperature values (3466 K). Thermal imaging infra-red imaging analysis also supported the observation of reduced Tj and Rth values from transient analysis and indicated lower chip surface temperature ( Ts) at all driving currents.

Understanding Outdoor Cold Stress and Thermal Perception of the Elderly in Severely Cold Climates: A Case Study in Harbin

This study collected data through microclimate monitoring, surface temperature measurements, and questionnaire surveys, and used indicators, such as the universal thermal climate index (UTCI), surface temperature (Ts), and wind chill temperature (tWC), to determine the thermal comfort threshold of the elderly in severely cold climates and evaluate their cold stress. The results indicated that (1) the neutral UTCI (NUTCI) for elderly individuals in winter was 13.3 °C, and the NUTCI range was from 1.4 to 25.2 °C; (2) the intensity of elderly individuals’ physical activity affected the magnitude of risk of whole-body cooling, with duration-limited exposures corresponding to 0.5, 3.3, and over 8 h for light, moderate, and vigorous activity levels, respectively; (3) the tWC in all four spaces was below −10 °C, potentially inducing discomfort or even frostbite in the elderly; (4) for a 10 s touch, the maximum Ts (−17.2 °C) of stone was lower than the numbness threshold (−15.0 °C), while that (−15.1 °C) of steel materials remained below the frostbite threshold (−13 °C), posing risks for the elderly during physical activity. This study’s results will provide valuable insights and theoretical references for the landscape design of urban park activity spaces for elderly individuals in cold climate regions.

Dynamic changes in evapotranspiration, canopy photosynthesis and expansive growth in open field under rapid fluctuating radiation

In open fields, plants experience dynamic changes in environment, particularly radiation, temperature, wind, and humidity but their short-term responses have not been adequately characterized under natural conditions. In this study, we assessed causal effects of rapid radiation fluctuation on seven plant parameters in open fields of cotton and sweet corn canopies. The parameters are evapotranspiration (ET), canopy photosynthesis indicated by CO2 flux from air to canopy (FCO2), sensible heat energy flux (H), canopy conductance for water vapor (gcw), canopy surface temperature (Ts), shoot and leaf elongation rate, and stem diameter change. The energy and CO2 fluxes were measured with Bowen ratio/energy balance/CO2 gradient (BREB+) technique, using averaging time of 5 min. Shoot + leaf elongation and stem diameter change were monitored with position transducers using averaging time of 1 min. All parameters were all found to respond to change in radiation and transpiration within minutes or sooner. While radiation effects on canopy gas exchanges are expected, illuminating are the indirect but immediate effects on shoot + leaf growth and stem diameter change through radiation effects on transpiration and plant water status. A novel finding is that gcw also responded within minutes or sooner to radiation fluctuations and that FCO2 was related almost linearly to gcw. Results are discussed in terms of soil-plant-atmosphere continuum, and interpreted in terms of dynamic interactions between transpiration and plant water status. The clear inverse relationship between ET and elongation rate or stem diameter changes provides additional evidence supporting the validity of 5-min averaging for the BREB + technique.

Consistent Ground Surface Temperature Climatology Over China: 1956–2022

AbstractThe ground surface represents the land‐atmosphere interface and plays a crucial role in exchanging energy, matter, and biochemical fluxes. The ground surface temperature (Ts) is hence widely investigated as an indicator to understand the thermal state of soil in a warming world. However, regular and continuous Ts measurements are rare worldwide, and the early Ts records were derived from snow surface measurements and are not comparable with the measurements of modern automatic systems. In this study, we reconstruct the Ts records of the China Meteorological Administration (CMA) for 1956–2022 by numerical simulation. The results show that the mean annual ground surface temperature (MAGST) during 1981–2010 ranged from 0.4 to 30.8°C at 632 stations. The MAGST was mainly controlled by air temperature and refined by snow depth. The overall MAGST increased by 0.20 ± 0.02°C dec−1 across China during 1956–2022 and showed pronounced interdecadal variability corresponding to the surface air temperature (0.23 ± 0.03°C dec−1). At the snow‐covered sites, the Ts warming was amplified by increased snow depth, leading to about 0.24°C dec−1 (or 70.6%) faster warming for Ts in winter compared to that of surface air temperature. Many of the early reported ground surface temperature studies based on CMA measurements did not consider the measurement inconsistency and likely overestimated the warming trend of ground surface temperature over China.

Feasibility of Using SWIR-Transformed Reflectance (STR) in Place of Surface Temperature (Ts) for the Mapping of Irrigated Landcover

(1) Background: A simple approach to map irrigated landcover has been introduced by using measures derived from the optical spectral range as an alternative to the thermal range. It has been demonstrated that substituting surface temperature (Ts, ‘thermal approach’) with SWIR-transformed reflectance (STR, ‘optical approach’) to detect surface moisture is feasible with comparable results. (2) Methods: Using an iterative thresholding procedure to minimize within-class variance, the bilevel segmentation of variables derived from Landsat-8 representing surface moisture and vegetation cover was achieved for the 2020–2021 summer for a key irrigation district in Australia. (3) Results: The results of irrigated landcover by the optical approach were found to be comparable with those obtained by the thermal approach. The classification accuracy was assessed using water delivery records at the farm level. Although the overall accuracy was high in both cases, the optical approach (97.6%) performed slightly better than the thermal approach (93.9%). (4) Conclusions: The feasibility of using STR to map irrigated landcover has been confirmed by a high-level overall accuracy assessment. This has broader implications in terms of irrigated landcover assessment, as the use of satellite imagery in these applications may not necessarily be limited to microwave or thermal sensors.

The A1 Adenosine Receptor Agonist N6 Cyclohexyl Adenosine Suppresses the Cold-Defense Threshold to a Surface Temperature Below 4°C in Sprague Dawley Rats

A1 adenosine receptor (A1AR) agonists have applications in targeted temperature management (TTM) for neurogenic fever, cardiac arrest and neonatal ischemic encephalopathy. By mitigating the cold-defense response the A1AR agonist N6 cyclohexyl adenosine (CHA) blocks shivering and cold-defense metabolic stress that limits the application and benefit of TTM. Stimulating CNS A1AR inhibits cold-induced shivering and nonshivering thermogenesis in rats and induces a torpor-like response in rats and hibernating species [1,2]. Dynamic control of surface temperature (Ts) in rats, designed to mimic conductive cooling used clinically, is an effective means to regulate body temperature after CHA [3]. In prior studies 17°C was the minimum Ts tested while in the clinic a fast rate of cooling is facilitated by setting cooling devices to 4°C. Unknown is if CHA suppresses the cold-defense response at a Ts of 4°C. The present study tests the hypothesis that the cold-defense threshold of CHA (1.0mg/kg, IP) is less than a Ts of 4°C, and we ask if the threshold differs between sexes. To define the cold-defense threshold, male and female Sprague-Dawley rats fed ad lib and housed at 20°C and 12:12 L:D were held overnight in a metabolic cage with a temperature-controlled surface set to 29°C and a video camera. The following day after 4h at 29°C with lights on, rats were injected with vehicle (week 1) or CHA (week 2) and the Ts was decreased to 28, 20, 16, 12, 8 and 4°C for 30min each. Cold-defense was assessed by an increase in the rate of oxygen consumption (VO2) and by behaviors suggestive of escape. Based on prior work showing a bimodal distribution of rats that respond to CHA and those that do not respond [4], we a priori chose to assess the proportion of nonresponders in the study population and to analyze responders and nonresponders separately. Of 9 rats (5 M, 4 F), one male did not respond to CHA. In rats that responded to CHA, vehicle (veh) treatment increased VO2 at Ts of 16°C to 4°C in both sexes (p&lt;0.0001 drug x Ts, 2-way RM ANOVA; p&lt;0.01, veh-29°C (lights on) vs veh-16, 12, 8, and 4°C, Tukey, n=8,8). CHA treatment decreased VO2 at all Ts tested (p&lt;0.05 CHA vs Veh, Tukey, n=8,8). Females trended towards higher VO2 at 29°C than males at all Ts, but sex differences decreased after treatment with CHA. Blinded analysis of behavior is in progress. Results show that CHA lowers the threshold of Ts induced cold-defense from 16°C to below 4°C. Suppressed VO2 at Ts above 16°C illustrates CHA-induced metabolic suppression unrelated to thermogenesis. Results inform optimal Ts to minimize time to reach target temperature without a cold-defense response. 1. Jinka et al., 2011, J Neurosci 31 (30):10752-10758. 2. Tupone et al., 2013, J Neurosci 33 (36):14512-14525. 3. Laughlin et al., 2018, Ther Hypothermia Temp Manag 8 (2):108-116. 4. Bailey et., 2017, J Pharm Exp Ther 362 (3):424-430. NNX13AB28A, 22-22EPSCoR-0018, P20GM130443, P20GM103395. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Interchangeability of multi-decade skin and surface air temperature trends over land in models

Satellite land surface temperature (Ts ) records have now reached 20+ year length, but their trends may differ from historical records built from in-situ measurements of near-surface air temperature (Tas ). In the ERA5 reanalysis, 60° S–60° N land Ts and Tas trends can differ by up to ±0.06 °C decade−1 over 20 years, depending on the period, or more on smaller spatial scales. Here I use 1979–1998 outputs from ACCESS1-0 climate model simulations with prescribed land Ts to understand changes in Ts and Tas . CO2’s effective radiative forcing causes adjustments that warm Tas relative to Ts . In ACCESS1-0, vegetation enhances the adjustments to CO2 over land. Meanwhile, feedbacks in ACCESS1-0 oppose the adjustments, resulting in small long-term net effects on global temperature estimates. In coupled simulations from other models, there is no agreement on whether Ts or Tas warms more and the most extreme case shows global long-term differences of just 5% between land Ts or land Tas trends. The results contrast with over-ocean behavior where adjustments and feedbacks reinforce each other, and drive larger long-term Tas warming relative to Ts across all models.

Convective heat transfer into moving fluid from a heated prolate spheroid

A common assumption in heat transfer models that involve fluid-solid interactions is that solid particles have a spherical shape. However, in numerous engineering applications, it is crucial to gain insights into the heat transfer mechanisms involving non-spherical particles and flowing fluids. These processes often employ particles with altered shapes, such as elongated geometries resembling prolate spheroids.A numerical study of airflow past a stationary constrained prolate spheroid under forced convective heat transfer is performed. A large temperature difference of the spheroid's surface was maintained relative to free stream temperature. Navier-Stokes and energy equations were solved to investigate the impact of Reynolds number (Re) and aspect ratio (AR) on convective heat transfer rate and Nusselt number (Nu). We focus on a wide range of spheroids' surface temperatures up to 1500 K in our study, which has never been studied in depth before. The simulations show that the mean Nu has a positive dependence on Ts, AR, and Re.A new correlation has been introduced that calculates the average Nusselt number (Nu) for spheroidal particles without assuming an isothermal condition (where the surface temperature Ts is roughly equal to the ambient temperature T∞). The suggested correlation incorporates the influence of AR, surface temperature, and Re.

Weekly rhythms of urban heat islands: A multicity perspective

Investigating the weekly rhythms of urban heat islands (UHIs) is critical for gaining deep insights into the urban climate changes caused by periodic cycles of human activities. However, the weekly rhythms of both canopy and surface UHIs (termed Ic and Is) remain poorly understood at a large spatial scale. Leveraging daily screen-level air temperature (Ta) and satellite land surface temperature (Ts) observations (2015∼2020), we show that the weekly rhythms of Ic averaged for all selected cities exhibit an evident peak-and-valley pattern across most seasons, with the annual mean Ic reduction during weekends of 0.09 ± 0.01 K (mean ± S.E., p < 0.05) for daytime and 0.10 ± 0.01 K (p < 0.05) for nighttime when compared to weekdays. In contrast, the Is only displays a pronounced weekly rhythm during winter daytime, with the corresponding Is reduction during weekends of 0.07 ± 0.01 K (p < 0.05) relative to weekdays. These findings remain robust against potential observation errors in Ta and Ts. From an intra-city perspective, both Ic and Is reductions during weekends escalate with increasing urban impervious surface percentage. This study illustrates the significance of short-term cycles of human activities in shaping global urban climates.

Comparison of CWSI and Ts-Ta-VIs in moisture monitoring of dryland crops (sorghum and maize) based on UAV remote sensing

Monitoring agricultural drought using remote sensing data is crucial for precision irrigation in modern agriculture. Utilizing unmanned aerial vehicle (UAV) remote sensing, we explored the applicability of an empirical crop water stress index (CWSI) based on canopy temperature and three-dimensional drought indices (TDDI) constructed from surface temperature (Ts), air temperature (Ta) and five vegetation indices (VIs) for monitoring the moisture status of dryland crops. Three machine learning algorithms (random forest regression (RFR), support vector regression, and partial least squares regression) were used to compare the performance of the drought indices for vegetation moisture content (VMC) estimation in sorghum and maize. The main results of the study were as follows: (1) Comparative analysis of the drought indices revealed that Ts-Ta-normalized difference vegetation index (TDDIn) and Ts-Ta-enhanced vegetation index (TDDIe) were more strongly correlated with VMC compared with the other indices. The indices exhibited varying sensitivities to VMC under different irrigation regimes; the strongest correlation observed was for the TDDIe index with maize under the fully irrigated treatment (r=−0.93). (2) Regarding spatial and temporal characteristics, the TDDIn, TDDIe and CWSI indices showed minimal differences Over the experimental period, with coefficients of variation were 0.25, 0.18 and 0.24, respectively. All three indices were capable of effectively characterizing the moisture distribution in dryland maize and sorghum crops, but the TDDI indices more accurately monitored the spatial distribution of crop moisture after a rainfall or irrigation event. (3) For prediction of the moisture content of single crops, RFR models based on TDDIn and TDDIe estimated VMC most accurately (R2>0.7), and the TDDIn-based model predicted VMC with the highest accuracy when considering multiple-crop samples, with R2 and RMSE of 0.62 and 14.26%, respectively. Thus, TDDI proved more effective than the CWSI in estimating crop water content.

Habitat Utilization and Behavioral Patterns of the Endemic Sri Lankan Green Pit Viper (Craspedocephalus trigonocephalus) in the Wet Zone of Sri Lanka

Behavioral patterns and habitat utilization of the endemic Green Pit Viper (GPV) Craspedocephalus trigonocephalus were studied in the wet zone of Sri Lanka. The region, which is covered by the wet zone, has no significant dry periods and a moderately high mean annual rainfall of over 2,500 mm. Data collection occurred between April 2021 and March 2022 with a total of 260 hours of standardized sampling effort distributed throughout the collection period. The method used was an active search which consists of a visual search of up to six meters from the central line along each side of the quadrate. Quadrats were placed in habitats, taking each GPV sighting as the center of a quadrate. At each GPV-occupied quadrat, ambient temperature, body surface temperature, prey availability, perch position and perch light level were recorded. The day was divided into six-time periods as; early morning, morning, mid-day, evening, late evening, and night. Activity level was determined considering the number of GPV that could be visually observed. A total of 49 GPV were examined during the study. Focal animal sampling was conducted, and an ethogram was developed. A strong positive relationship was observed between ambient temperature (Ta) and body surface temperature (Ts) of GPVs (Pearson correlation r=0.936). The highest number of individuals preferred filtered sun light (57.14%). C. trigonocephalus mostly preferred distal position on the branches followed by middle and apical. There was a significant difference in the percentage of individuals with different behaviors [ANOVA, F=3.64, p&lt;0.05]. Behavioral pattern of GPV varied in the temporal scale during the day. During the morning time slot, C. trigonocephalus spent most of the time ambushing (16.12%) and basking (6.42%) respectively. During the mid-day they spent most of their time basking (10.57%), followed by resting (7.15%). The evening, late evening, night, and early morning slots were spent mostly on ambushing. The highest average time of 239 min was spent on ambushing behavior. Feeding behavior (9.8 min) had relatively short time on average. Results of this study indicate that C. trigonocephalus is well adapted for the utilization of its preferred habitat in the wet zone, and that, it displayed behavioral patterns that vary within temporal scales, which results in more efficient and effective utilization of resources. Therefore, this study provides important insights for conservation and management of C. trigonocephalus by critically evaluating the requirements of this species. &#x0D; Keywords: Craspedocephalus trigonocephalus, Behavior, Endemic pit viper, Wet zone

Nanofluid Drop Impact on Heated Surfaces.

We experimentally elucidate the impact dynamics of ethylene glycol (EG) droplets laden with both hydrophilic and hydrophobic SiO2 nanoparticles (NPs) onto a flat heated surface in non-boiling, boiling, and Leidenfrost regimes. We use seven nanofluid concentrations (Cp), ranging from 0.89 to 64.3 wt %, and control the surface temperature (Ts) between 100 and 400 °C, while the nanofluid droplet's impact velocity is constant at 0.22 ± 0.02 m/s. Phase diagrams of impact outcomes are established to illustrate the effect of the additive nanoparticles on the droplets' impact dynamics, revealing that nanoparticles modify droplet impact behaviors differently in each regime. In the non-boiling regime, the droplet spreading profile remains unaffected by nanoparticles up to Cp < 11.9 wt % before reaching the maximum spreading diameter (βmax). For nanofluid drops with higher nanofluid concentration, the increasing viscosity with concentration is likely to be the primary factor that affects the droplets' spreading profile in the non-boiling regime Ts ≲ Tsat ≈ 200 °C, as the saturation temperature. In the boiling regime 200 °C < Ts ≲ 350 °C, a small amount of nanoparticle addition (Cp = 0.89 wt %) promotes atomization regardless of nanoparticle wettability. Finally, manifested in a complete rebound due to an intervening vapor layer, the Leidenfrost temperature (TL) of the nanofluid droplets is affected by both nanofluid concentration and nanoparticles' wettability. The nanofluid droplets' TL increases with higher nanofluid concentration; moreover, this Leidenfrost temperature increment is more significant for EG droplets laden with hydrophobic nanoparticles. Our results quantitatively reveal the significant influence of nanoparticle concentrations and wettability on drop spreading, impact outcome, and Leidenfrost temperature on heat surfaces, potentially benefiting applications in coating, spraying, and cooling.

A study of the formation of fuzzy tungsten in a HiPIMS plasma system

Nanostructured ‘fuzzy’ tungsten has been grown for the first time in a high-power impulse magnetron sputtering high power-impulse magnetron sputtering-(HiPIMS) system. The fuzzy layers were formed over range of surface temperatures T s, from 1025 to 1150 K, for helium ion fluences of 5.02 × 1024 m−2, and mean ion bombardment energy of 55 eV. The time-evolution of the helium ion flux (ΓHe) and incident energy (E He) were determined during the HiPIMS pulse (of width of 150 μs) using a planar Langmuir probe. The micrographic findings revealed that, the thickness of HiPIMS-grown nano-tendrill layers increased by 83% (from 274 to 501 nm) for only a 125 K rise in T s. This result is explained by the fact that higher surface temperatures led to larger helium bubbles which ultimately produce a thicker nanostructured layer. The growth rate of fuzzy tungsten layers in HiPIMS conditions is approximately 50% lower than those observed for DC magnetron operation.

The Land Wet‐Bulb Temperature Increases Faster Than the Sea Surface Temperature

AbstractVapor buildup in the atmosphere and faster warming over land than over ocean are ubiquitous features of climate change. This combination is a threat to society because the associated heat stress may exceed the limit for human survival. The heat stress due to high humidity and high temperature is quantified with the wet‐bulb temperature (Tw). A common view is that the land Tw should change at the same rate as the ocean surface temperature (Ts). Using climate model data and atmospheric observations, we show that the land Tw increases 17% faster than Ts. This amplification arises from stronger downward longwave radiation (L↓) at the surface in a warmer climate, which causes moist static energy to accumulate in the atmospheric boundary layer. We also find that L↓ is a better predictor of Tw than Ts at interannual to decadal time scales. These relationships are robust across climates and across model simulations.