Surface Temperature Measurements Research Articles

Combined Thermal Index Development for Urban Heat Island Detection in Area of Split, Croatia

Urban heat islands (UHIs) are a phenomenon of temperature rising within urban areas relative to their rural counterparts. UHIs are becoming an increasingly common problem in large cities, which appear due to excessive urbanization and reductions in natural cover and vegetation. This phenomenon negatively affects the quality of life of the residents of the affected city, causing discomfort, reducing air quality, and increasing energy demand. In this study, UHIs were detected and analyzed in the city of Split, Croatia, using data from the Landsat 8 and 9 satellite missions and ground-based measurements of air and land surface temperatures, which were conducted in July, August, and September 2024. This research compares ground-based and sensor-based temperatures, and their analysis results in the proposal of a new index: the Combined Thermal Index. The main feature of this new index, which combines measured and perceived temperature, is to improve the understanding of the impact of UHIs in the city (Split), compared to existing indices. So far, LST and air temperature have not been combined, nor have they been combined with human perception of temperature, which is important in the case of UHIs because it is these people who will ultimately feel a rise in temperature.

Intercomparison of satellite-derived SST with logger data in the Caribbean—Implications for coral reef monitoring

Since the early 1980s measurements of Sea Surface Temperature (SST) derived from satellite-borne instruments have provided a wide range of global gridded products documenting changes in SST. However, there are many sources of uncertainty in these records and significant differences exist among them. One use of these products is identification of coral bleaching events, and the predictions of the impact of future warming on coral reefs. This relies on an understanding of how temperatures near reefs as recorded by SST products differ from the in-situ SST experienced by the corals. This difference is a combination of real spatio-temporal variations, inadequate in product resolution and errors in the products. This paper investigates the relationship between the local temperature measured in-situ by loggers at coral sites in the western tropical Atlantic and two high resolution satellite SST products. Using differences among ESA SST CCI v2.1 (CCI analysis SST), NOAA CoralTemp SST products and in-situ logger data from coral reefs, an assessment of the satellite products with focus on coral reef monitoring is carried out. Discrepancies between the two products can be large, especially in coastal areas and for the warmest and coldest months when there is a particular risk of bleaching. By comparison to the stable CCI analysis SST product, CoralTemp was found to overestimate the rise in SST by as much as 0.20°C per decade. In almost all cases SSTs from CCI analysis SST were more consistent with temperatures measured near the corals than those from CoralTemp.

Seagrass wasting disease prevalence and lesion area increase with invertebrate grazing across the northeastern Pacific.

Disease is a key driver of community and ecosystem structure, especially when it strikes foundation species. In the widespread marine foundation species eelgrass (Zostera marina), outbreaks of wasting disease have caused large-scale meadow collapse in the past, and the causative pathogen, Labyrinthula zosterae, is commonly found in meadows globally. Research to date has mainly focused on abiotic environmental drivers of seagrass wasting disease, but there is strong evidence from other systems that biotic interactions such as herbivory can facilitate plant diseases. How biotic interactions influence seagrass wasting disease in the field is unknown but is potentially important for understanding dynamics of this globally valuable and declining habitat. Here, we investigated links between epifaunal grazers and seagrass wasting disease using a latitudinal field study across 32 eelgrass meadows distributed from southeastern Alaska to southern California. From 2019 to 2021, we conducted annual surveys to assess eelgrass shoot density, morphology, epifauna community, and the prevalence and lesion area of wasting disease infections. We integrated field data with satellite measurements of sea surface temperature and used structural equation modeling to test the magnitude and direction of possible drivers of wasting disease. Our results show that grazing by small invertebrates was associated with a 29% increase in prevalence of wasting disease infections and that both the prevalence and lesion area of disease increased with total epifauna abundances. Furthermore, these relationships differed among taxa; disease levels increased with snail (Lacuna spp.) and idoteid isopod abundances but were not related to abundance of ampithoid amphipods. This field study across 23° of latitude suggests a prominent role for invertebrate consumers in facilitating disease outbreaks with potentially large impacts on coastal seagrass ecosystems.

The Utility of Skin Surface Temperature measurement in the prediction of Diabetic Foot Ulceration.

The Utility of Skin Surface Temperature measurement in the prediction of Diabetic Foot Ulceration.

Ultra-fast etching of photoresist by reactive atmospheric-pressure thermal plasma jet with surface temperature measurement

Abstract Atmospheric-pressure reactive thermal plasma jet (R-TPJ) with Ar and O2 gas mixture was applied to etching of photoresist (PR) on silicon wafer. An optical interference contactless thermometry (OICT) and optical emission spectroscopy were carried out to clarify the relationship between the etching rate, amount of atomic oxygen radicals, and PR surface temperature. The results show that O2 flow rate and surface temperature are obviously related to the etching rate of PR. The R-TPJ irradiation with input current at 60 A reaches surface temperature of 720 K within 7 ms and achieved etching rate of 84 μm/s.

Orifice plate surface temperature measurement of a LaB6 hollow cathode using a near-infrared two-color radiation thermometer

This study measured the two-dimensional orifice plate surface temperature of a 20-A-class LaB6 hollow cathode using a near-infrared two-color radiation thermometer. The thermometer technique resolved the orifice plate temperature with an accuracy of approximately 166 ℃. With this technique, the surface temperature of the orifice plate was found nearly uniform, with no observed temperature gradient on the orifice plate. Consequently, the operational characteristics of the hollow cathode are discussed in relation to the average surface temperature. Data analysis revealed that the orifice plate temperature was not sensitive to the mass flow rate; conversely, it was highly sensitive to the discharge current. Moreover, for the same input power, the orifice plate temperature was higher in the high-current, low-voltage mode also known as the spot mode indicating efficient emitter heating. The measurement system developed in this study provides a more precise evaluation of the orifice plate temperature and allows for estimating the internal conditions of a hollow cathode, thus facilitating more appropriate design evaluations under various operating conditions.

Shipborne comparison of infrared and passive microwave radiometers for sea surface temperature observations

Abstract. In the spring of 2021, a shipborne comparison of sea surface temperature (SST) measurements was undertaken using thermal infrared (IR) and passive microwave (PMW) radiometers. The Danish Meteorological Institute (DMI) and the Technical University of Denmark (DTU) jointly deployed two IR and two PMW instruments aboard the Norröna ferry, which traversed between Denmark and Iceland for a week. The primary objective was to assess the proximity-based comparison of IR and PMW measurements, minimizing atmospheric influences and providing valuable insights into reconciling IR- and PMW-derived SSTs. A linear regression algorithm was developed using IR SST data as a reference to derive PMW SST from brightness temperature. The data analysis primarily focused on evaluating data variability, identifying discrepancies between IR and PMW SST, and assessing the overall uncertainty in the retrieval process. The overall root-mean-square error (RMSE) of the retrieved PMW SST was 0.88 K during the ship's motion and 0.94 K when the ship was moored. The analysis of the retrieved SST uncertainty budget involved the consideration of observed quantities and a forward model, accounting for factors like instrument noise, wind speed, incidence angle, and the RMSE of skin and sub-skin temperature. The resulting uncertainty budget in the retrieved PMW SST indicated 0.53 K for the data acquired during motion and 0.3 K for data collected during a port stay. Based on the analyses of the collected data and uncertainty estimations, recommendations are offered to improve future inter-comparisons and help reconcile IR and PMW measurements.

Observation Angle Effect of Near-Ground Thermal Infrared Remote Sensing on the Temperature Results of Urban Land Surface

During the process of urbanization, a large number of impervious land surfaces are replacing the biologically active surface. Land surface temperature is a key factor reflecting the urban thermal environment and a crucial factor affecting city livability and resident comfort. Therefore, the accurate measurement of land surface temperature is of great significance. Thermal infrared remote sensing is widely applied to study the urban thermal environment due to its distinctive advantages of high sensitivity, wide coverage, high resolution, and continuous measurement. Low-altitude remote sensing, performed using thermal infrared sensors carried by unmanned aerial vehicles (UAVs), is a common method of land surface observation. However, thermal infrared sensors may experience varying degrees of sway due to wind, affecting the quality of the data. It is still uncertain as to what degree angle changes affect thermal infrared data in urban environments. To investigate this effect, a near-ground remote sensing experiment was conducted to observe three common urban land surfaces, namely, marble tiles, cement tiles and grasses, at observation angles of 15°, 30°, 45°, and 60° using a thermal infrared imager. This is accompanied by synchronous ground temperature measurements conducted by iButton digital thermometers. Our results suggest that the temperature differences between the remote sensing data of the land surface and the corresponding ground truth data increase as a function of the increasing observation angle of the three land surfaces. Furthermore, the differences are minor when the observation angle changes are not more than 15° and the changes are not the same for different land surfaces. Our findings increase the current understanding of the effects of different angles on thermal infrared remote sensing in urban land surface temperature monitoring.

A Simple Power Loss Evaluation Method for High-Frequency Transformers Based on Surface Temperature Measurement Within Wide Operation Range

A Simple Power Loss Evaluation Method for High-Frequency Transformers Based on Surface Temperature Measurement Within Wide Operation Range

High-Resolution Nearshore Sea Surface Temperature from Calibrated Landsat Brightness Data

Understanding and monitoring nearshore environments is essential, given that these fine-scaled ecosystems are integral to human well-being. While satellites offer an opportunity to gain synchronous and spatially extensive data of coastal areas, off-the-shelf calibrated satellite sea surface temperature (SST) measurements have only been available at coarse resolutions of 1 km or larger. In this study, we develop a novel methodology to create a simple linear equation to calibrate fine-scale Landsat thermal infrared radiation brightness temperatures (calibrated for land sensing) to derive SST at a resolution of 100 m. The constants of this equation are derived from correlations of coincident MODIS SST and Landsat data, which we filter to find optimal pairs. Validation against in situ sensor data at varying distances from the shore in Northern California shows that our SST estimates are more accurate than prior off-the-shelf Landsat data calibrated for land surfaces. These fine-scale SST estimates also demonstrate superior accuracy compared with coincident MODIS SST estimates. The root mean square error for our minimally filtered dataset (n = 557 images) ranges from 0.76 to 1.20 °C with correlation coefficients from r = 0.73 to 0.92, and for our optimal dataset (n = 229 images), the error is from 0.62 to 0.98 °C with correlations from r = 0.83 to 0.92. Potential error sources related to stratification and seasonality are examined and we conclude that Landsat data represent skin temperatures with an error between 0.62 and 0.73 °C. We discuss the utility of our methodology for enhancing coastal monitoring efforts and capturing previously unseen spatial complexity. Testing the calibration methodology on Landsat images before and after the temporal bounds of accurate MODIS SST measurements shows successful calibration with lower errors than the off-the-shelf, land-calibrated Landsat product, extending the applicability of our approach. This new approach for obtaining high-resolution SST data in nearshore waters may be applied to other upwelling regions globally, contributing to improved coastal monitoring, management, and research.

Ultra-thin sealing surface treatments for solar radiation screening on asphalt facing dams

Bituminous materials are widely used in a large range of hydraulic applications due their excellent waterproofing properties. More than 300 asphalt facing reservoirs were built in the last century, presenting higher mechanical and hydraulic performance when compared with other facing alternatives, such as cement concrete or steel membranes. On the other hand, the dark colour of bitumen may lead to high temperatures inside asphalt paved system, affecting long term ageing of binder and jeopardizing the quality of the impervious layer. Recently, multifunctional ultra-thin surface treatments are becoming an alternative to demolition-reconstruction of the impervious layer, significantly abating the quantity of energy and raw materials required for maintenance. High-reflective surface treatments may represent also an effective solution to reduce the temperature of asphalt layers, extending the service life of the dam embankment and reducing the need of maintenance. In fact, there is a lack of literature concerning the assessment of thermal impact on asphalt dams. In the light of above, a number of different combinations of sealing surface treatments were investigated in this study. An ad hoc testing equipment and procedure were designed to perform an artificial solar irradiance test. A complete colorimetry analysis was performed and the outcomes were compared with temperature data, making use of a thermal camera and of embedded sensors for surface and base temperature measurements, respectively. Major results and their relationships have been commented in-depth along with proposed further research activities.

Solar-optical and thermal behavior of photochromic glazing: Small-scale testing under real sky conditions

The poor performance of conventional building glazing, which is usually responsible for large climatization needs and glare problems, has been promoting the development of innovative smart glazing technologies with an improved performance. Photochromic glazing, a type of smart glazing, exhibits a dynamic behavior by darkening/bleaching in reaction to the presence/absence of solar radiation. The aim of this study is to evaluate the thermal and solar-optical behavior of a photochromic filmed clear glazing, against the same glazing without film, through experimental tests. The transmittance and reflectance spectra of the glazing solutions were initially measured with a spectrophotometer. Then two small-scale models were used to assess the behavior of the glazing solutions under real sky conditions (clear and overcast). The thermal behavior was assessed through air and surface temperature measurements. The solar-optical behavior was investigated through solar radiation and illuminance measurements, which were also used to compute the solar and visible transmittance of the glazing systems, respectively. The dynamic behavior of the photochromic film resulted on a reduction of 14 % of the interior temperature. Interior illuminance and irradiance levels were significantly reduced with the film, corresponding to 10–50 % and 15–35 % visible and solar transmittance values of the photochromic glazing, respectively.

Multiple Preheating Processes for Suppressing Liquefaction Cracks in IN738LC Superalloy Fabricated by Electron Beam Powder Bed Fusion (EB-PBF).

In additive manufacturing, controlling hot cracking in non-weldable nickel-based superalloys poses a significant challenge for forming complex components. This study introduces a multiple preheating process for the forming surface in electron beam powder bed fusion (EB-PBF), employing a dual-band infrared surface temperature measurement technique instead of the conventional base plate thermocouple method. This new approach reduces the temperature drop during forming, decreasing surface cooling by 28.6% compared to traditional methods. Additionally, the precipitation of carbides and borides is reduced by 38.5% and 80.1%, respectively, lowering the sensitivity to liquefaction cracking. This technique enables crack-free forming at a lower powder bed preheating temperature (1000 °C), thereby improving the powder recycling rate by minimizing powder sintering. Microstructural analysis confirms that this method reduces low-melting eutectic formation and alleviates liquefaction cracking at high-angle grain boundaries caused by thermal cycling. Consequently, crack-free IN738 specimens with high-temperature durability were successfully achieved, providing a promising approach for the EB-PBF fabrication of crack-resistant IN738 components.

Rocks and walls: Biodiversity and temperature regulation of natural cliffs and vertical greenery systems

Loss of natural habitats and increased human activity results in warming up of cities and a reduced biodiversity. Vertical greenery systems (VGSs) have been proposed to mitigate rising temperatures and the loss of biodiversity. So far, studies on existing VGSs have only analysed a single ecosystem service and their performance has not been compared to that of their natural counterparts. Here, air and surface temperature measurements as well as biodiversity observations were conducted on two different types of existing VGSs (climber, foliage) on buildings in Singapore and compared to non-vegetated building walls and vegetated natural cliffs. Our results show that VGSs act as temperature buffer creating a cooling layer towards the building wall during the day and a warming layer during the night. Furthermore, VGSs host significantly more animals than non-vegetated walls, however, VGS have less animals than vegetated natural cliffs. Moreover, a positive correlation was found between the amount of surrounding vegetation (green cover, tree density within 10 m of VGS), thickness of vegetation, plant richness on VGS and biodiversity observed on VGSs. Together, VGSs not only contribute with their aesthetics but can also be used to regulate daytime temperature in a tropical city like Singapore and to mitigate, at least in part, the loss of habitat for biodiversity.

Optimization of P-electrode structures to enhance current spreading uniformity in micro-LEDs.

In this study, we designed and fabricated parallel-connected green micro-LEDs with three different P-electrode configurations: rounded (Sample A), cross-shaped (Sample B), and circular (Sample C). We then systematically evaluated the impact of these electrode shapes on the devices' optoelectronic performance. The results show that the shape of the P-electrode significantly influences the optoelectronic performance of micro-LEDs. With a round mesa, Sample C exhibits the lowest operating voltage and the smallest dynamic resistance and achieves a peak external quantum efficiency (EQE) of 19.57%, which is 25.53% and 11.13% higher than that of Sample A (15.59%) and Sample B (17.61%), respectively. The analysis suggests that this improvement is mainly due to enhanced uniformity in current spreading and shorter current injection paths. COMSOL simulations, along with thermal resistance and surface temperature measurements, confirm that different P-electrode shapes affect the uniformity of current distribution in micro-LEDs, which in turn impacts the device's thermal performance. TracePro simulation results further demonstrated that circular P-electrodes optimize the light output of the device. We believe that this study provides a valuable reference for the design and fabrication of micro-LED chips.

Thermographic and ultrasound assessment in patients with rheumatoid arthritis: can thermography detect subclinical synovitis at the wrist?

BackgroundThermography is an emerging imaging modality which allows for a quick and objective measure of joint surface temperature in patients with rheumatoid arthritis (RA). To date, there are no published studies comparing thermography with ultrasonography in the subclinical assessment of joint inflammation at the wrist of patients with RA, and no published data on inter-rater reliability for multiple raters for thermographic assessment at the RA wrist. In our study comparing thermography and ultrasonography at the RA wrist, we aim to determine if thermography can detect subclinical synovitis. Additionally, we performed inter-reliability testing (multiple raters) for both thermography and ultrasonography.MethodsThermographic (average (Tavg), maximum (Tmax) and minimum (Tmin) temperatures) and ultrasound (total grey-scale (TGS) score and total power Doppler (TPD) scores) parameters were compared between two patient groups: Asymptomatic Group (with non-swollen and non-tender wrists) and Symptomatic Group (with swollen and/or tender wrists). Among Asymptomatic Group patients, thermographic parameters were compared between those with and without wrist joint recess(es) having ultrasound synovitis (PD ≥ 1 or GS ≥ 2); Spearman’s correlation and simple linear regression were used to study the relationship between thermographic and ultrasound parameters. Intra-class correlation coefficient (ICC) was used for inter-rater reliability calculation.ResultsEighty-seven RA patients’ right wrists were imaged in this cross-sectional study. Thermographic temperatures, TPD and TGS scores were all significantly (p < 0.05) greater among Symptomatic Group versus Asymptomatic Group patients. Among Asymptomatic Group patients, thermographic temperatures were all significantly higher (P < 0.01) in wrists having joint recess(es) with ultrasound PD ≥ 1 or GS ≥ 2, while all thermographic parameters correlated significantly with TPD (correlation coefficient ranging from 0.43 to 0.48, p < 0.001) and TGS (correlation coefficient ranging from 0.33 to 0.37, p < 0.01). The ICC values based on a subset of images obtained for inter-reliability testing were high for thermography (0.994 to 0.998) and ultrasonography (0.933 to 0.952).ConclusionsSwollen and/or tender RA wrists displayed greater thermographic and ultrasound-detected joint inflammation. At clinically quiescent (non-swollen; non-tender) wrists, thermographic temperatures significantly correlated with ultrasound-detected joint inflammation.Clinical trial numberNot applicable.

Perception and reconstruction of temperature field in forgings based on physical model and CNN model

Accurately perceiving and reconstructing the temperature field of hot-deformed large forgings is essential for intelligent forging and enhancing forging quality. In this study, the surface temperature of large forgings is measured using an infrared thermal imager. The relationship between the grayscale of infrared images and the surface temperature of large forgings is analyzed. A physical model, incorporating a convolutional neural network (CNN) model, is established to ascertain the surface temperature of large forgings. The CNN model utilizes standard convolution and multilayer perceptron modules for the backbone network and implements an adaptive learning rate. The correlation between three channel information and the surface temperature besides the grayscale is considered in the CNN model. Lastly, this study proposes a method for reconstructing the temperature field of large forgings based on the developed perception model, enabling accurate surface temperature measurement even when the large forgings are covered by oxide skin.

Undesired effects of low‐level photobiomodulation analgesic therapy in three cats with osteoarthritis

AbstractThree cats with osteoarthritis undergoing low‐level laser therapy showed undesired effects, namely, discomfort and behavioural changes, after their first laser session. Although visible burns could not be detected and rectal temperature was only slightly elevated compared to pre‐procedural values, it is hypothesised that the behavioural changes showed by all three cats, namely, restlessness, tail wiggling, flinching away from touch and frequent position changes, were caused by skin overheating, as it has been reported in human patients.It is advisable to intensify post‐procedural monitoring in cats undergoing photobiomodulation as part of the analgesic treatment of osteoarthritis for early detection of complications. Measurement of skin surface temperature of the treated areas and behavioural observation may be recommended in cats following photobiomodulation, possibly until 3‒4 h after the end of the laser treatment.

Systematic Review and Meta-Analysis of Thermal Stress Assessment in Poultry Using Infrared Thermography in Specific Body Areas.

Thermal stress is a health and welfare concern in the poultry industry. Poultry have specific thermoregulation strategies for heat stress (i.e., vasodilatation) or cold stress (i.e., vasoconstriction). Infrared thermal (IRT) analysis is a non-invasive temperature assessment technology with significant benefits compared to conventional temperature measurements, which are invasive and time-consuming. However, a wide range of IRT methodologies and equipment are used for temperature assessment in poultry. The aim of this study was to perform a systematic review and meta-analysis of IRT applications in poultry undergoing thermal stress. The bibliographic search yielded 17 records for qualitative synthesis and 10 for quantitative analysis. The results showed IRT is more commonly studied during heat stress than cold stress, and more research is being conducted on laying hens than other poultry species. Also, four body areas (parts of the head, body, face, and leg) were identified as common areas of interest for body surface temperature measurement. There is a clear thermoregulation response to thermal stress in poultry, with marked differences between featherless and feather-covered areas. IRT in poultry undergoing thermal stress has a good diagnostic value and represents an important welfare assessment tool for future research, particularly when combined with other welfare assessment methods.

Experimental study on high-precision measurement of surface temperature in friction stir welding aluminium alloy 2219 based on infrared thermometry

In friction stir welding (FSW) of aluminium alloy 2219, the welding temperature critically influences the weld quality. Accurate measurement of the welding temperature is essential for effective welding process control. However, the conventional approach of non-contact infrared thermometry faces significant challenges in FSW due to the inherently low and variable emissivity of aluminium alloys, making it susceptible to environmental radiation interference. This paper proposes a novel, high-precision method for measuring the surface temperature of FSW aluminium alloy 2219 based on infrared thermometry principles. Initially, the study delves into these principles, analysing factors that affect the accuracy of infrared thermometry in the context of FSW in industrial settings. To enhance the surface emissivity of the weldments, a high-emissivity coating is applied to the aluminium alloy surface. Additionally, strategic adjustments in the positioning of the thermal imager and careful selection of the measuring area effectively mitigate interference from the FSW tool’s radiation. Conventional methods report a temperature measurement error greater than 2%, while the proposed method reduces this error to 1.2%. The effectiveness and practical utility of the method are validated through FSW experiments on flat plates and rocket tank rings, corroborated by comparative analyses with surface thermocouple temperature measurements. This confirms the viability of the proposed method for high-precision temperature measurement in aluminium alloy FSW applications.