Temperature Variance Research Articles

July Mean Temperature Reconstruction for the Southern Tibetan Plateau Based on Tree-Ring Width Data during 1763–2020

Long-term climate records are essential for understanding past climate change and its driving forces, which could provide insights for adapting to future climate change. This paper presents a reconstruction of the July mean temperature based on the Smith fir tree-ring width data over 1763–2020 for the southern Tibetan Plateau (TP). The reconstruction explained 50.1% of the variance in the instrumental temperature records during the calibration period 1979–2020. The reconstruction matched well with other summer temperature reconstructions from neighboring regions and Northern Hemisphere temperatures. A significant warming trend was found from the 1960s, and the warming accelerated since the 1990s. In the reconstructed series, multiple-taper method analysis and wavelet analysis revealed significant periodicities of 2–4-year, 20–30-year, and 70–80-year. Moreover, the El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO) significantly influenced the July mean temperature in our study area. Our reconstruction can provide valuable data for climate change studies.

Preliminary investigation of saline water intrusion (SWI) and submarine groundwater discharge (SGD) along the south-eastern coast of Andhra Pradesh, India, using groundwater dynamics, sea surface temperature and field water quality anomalies.

Intensive anthropogenic activities along the coastal plains of Andhra Pradesh (such as urbanisation, agriculture and aquaculture) rely extensively on coastal fresh groundwater resources that are pumped at unsustainable rates causing groundwater decline and water quality problems due to saline water intrusion. Hydrogeological studies are imperative to implement groundwater conservation strategies in coastal Andhra Pradesh, which is experiencing a severe freshwater shortage due to overexploitation and saline water intrusion as well as clean water loss through the aquifer system close to the coastal plains. An attempt is made in this study to demarcate the submarine groundwater discharge (SGD) and saline water intrusion (SWI) zones adopting a three-tier validation system, i.e. groundwater dynamic, LANDSAT resultant sea surface temperature (SST) variance and site-specific water characteristics along the southeast coast of Andhra Pradesh, India. A total of 234 water samples (139 porewater, 31 groundwater and 64 seawater samples) were evaluated along ~ 450km southeast coastline of Andhra Pradesh. In situ porewater physio-chemical parameters, i.e. EC, TDS, pH, DO, temperature, and salinity, at every 1km except non-accessible areas and groundwater for every 5km were analysed and used for identification of SGD zones in the study area. The hydraulic gradient values vary from - 11 to 250m in post-monsoon and - 14 to 250m in pre-monsoon. And sea surface temperature anomaly for 2017, 2018 and 2019 varies between 21-39°C, 15-34°C and 20-39°C. Three districts out of the four districts studied (Krishna, Guntur and Nellore) were shown to be prone to SWI, whereas Prakasam district was susceptible for SGD. For the first time, this kind of preliminary study was carried out in the coastal Andhra Pradesh region, and it will serve as a basis for the meticulous analysis of the fresh and saline water mixing zones/process as well as to develop and manage the groundwater resources along the water-stressed coastal plains of Andhra Pradesh, India.

Experimental investigation on the phase behaviour for gas hydrates in CO2 rich gas mixtures & multiphase system

Almost 40% of undiscovered hydrocarbon reserves have high CO2 and H2S concentrations around the globe. So it is crucial to understand these hydrocarbon systems’ thermophysical properties for the excellent design of production facilities. An experimental investigation is conducted in this study to understand and evaluate the thermodynamic conditions of gas hydrate formation in natural gas systems with high CO2 levels gas and dominant multiphase (high CO2 level gases, deionized water, and crude oil). Three gas mixtures were chosen in this study to simulate natural gas with high CO2 content. The experiments are conducted within the critical pressure of the selected gas to avoid any phase change due to pressure. The impact of high CO2 levels in gas systems on the thermodynamic conditions of the gas hydrates was first explored. Then, the effect of a multiphase system was investigated after the addition of the oil phase into the system. The thermodynamic equilibrium conditions obtained from experiments were used to construct the Hydrate liquid–vapour Equilibrium (HLVE) curves, and the phase behaviour was studied. The details about the temperature variance and enthalpy are also clearly discussed. It has been discovered that gas mixtures with a higher CO2 content tend to promote compared to the pure methane gas system but inhibit compared the pure CO2 system. But in the multiphase system, all the gases show an inhibition effect compared to their respective pure gas system results.

Identification of Thermohaline Sheet and Its Spatial Structure in the Canada Basin

Abstract Thirty-four individual thermohaline sheets are identified at depths of 170–400 m in the Canada Basin of the Arctic Ocean by using the hydrographical data measured with the Ice-Tethered Profilers (ITPs) between August 2005 and October 2009. Each sheet is well determined because the salinity within itself remains very stable and the associated salinity anomaly is markedly smaller than the salinity jump between neighboring sheets. These thermohaline sheets are nested between the Lower Halocline Water (LHW) and Atlantic Water (AW) with lateral coherence of hundreds of kilometers and thickness varying from several to dozens of meters. The physical properties, including temperature, heat flux, and vertical turbulent diffusivity, in the sheet are found to be averagely associated with the AW propagation. Spatially, the thermohaline sheet is in a bowl-shaped distribution, which is deepest in the basin center and gradually becomes shallower toward the periphery. The interaction between the LHW and AW could be demonstrated through the property variances in the sheets. The temperature variances in the upper and lower sheets are correlated with the LHW and AW, respectively, transited at the 15th sheet, whereas the depth variance in the sheet is strongly correlated with the LHW. It is proposed that the sheet spatial distribution is mainly dominated by the Ekman convergence with the Beaufort Gyre, slightly modulated with the AW intrusion. Significance Statement The diffusive convection staircases, composed of consecutive steps containing thick mixed layers and relatively thin interfaces, are prominent between the Lower Halocline Water (LHW) and the Atlantic Water (AW) throughout the Canada Basin. This sheet-like structure is in a bowl shape with lateral coherence over hundreds of kilometers. It is proposed that the distribution of the thermohaline sheet is mainly dominated by the Ekman convergence with Beaufort Gyre, as well as the AW intrusion. The present method of thermohaline-sheet identification would have more implications beyond this work. Since the thermohaline sheet remains mostly stable and coherent on a very large spatial–temporal scale, it might play a similar role as the water mass analysis in numerous applications, e.g., climate change.

Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium

This paper investigates the effect of porous-media arrangement, hot-plate arrangement, heat flux, and inlet flow on the mixed convection heat transfer, and uniformity of temperature and concentration in an open enclosure. This model is considered for use as an adsorption treatment unit for radioactive waste gas in a nuclear medicine building. The radioactive waste gas flows through the cavity from bottom to top. The two-dimensional governing equations have been solved using the finite volume method. The Prandtl number and aspect ratio of the cavity are fixed at 0.71 and 1, respectively. The problem has been governed by five parameters: −10 ≤ Br ≤ 10, 10−6 ≤ Da ≤ 102, 0.1 ≤ Kc ≤ 10, 10−2 ≤ Ri ≤ 10, and 0.1 ≤ Kr ≤ 10, and the layouts of the porous layer and hot plates. The simulation results indicate that the Type C (polymeric porous media) has excellent heat transfer characteristics with a 10% increase in the Nusselt number (Nu). The contours of streamlines, isotherms and heatlines indicate that, with the increase of Richardson number (Ri), the trend of Nu varies for different arrangements of hot plates. It is interesting to note that the convective heat transfer of Type F (surrounded arrangement) was found to have the lowest Nu number for the same Ri number. The convective heat transfer is more pronounced for Type E (symmetrical arrangement). The Nu number of Type E (symmetrical arrangement) is about 110% higher than that of Type F (surrounded arrangement) and it is about 35% higher than that of Type D (centralized arrangement). This type also has a more uniform temperature distribution, as indicated by the temperature variance. The findings of this study can guide preheating system optimization.

On the Diffusivity of Moist Static Energy and Implications for the Polar Amplification Response to Climate Warming

Abstract Energy balance models (EBMs) have been widely used in a range of climate problems, but the assumption of constant diffusivity in the parameterization of the moist static energy (MSE) flux can hardly be justified. We demonstrate in this study that the diffusive MSE flux can be derived from the basic energy balance equation with a few tolerable assumptions. The estimated diffusivity is both spatially and seasonally dependent, and its midlatitude average is then tested against several scaling theories for the midlatitude eddy diffusivity. The result supports the diffusivity theory of Held and Larichev modified for the moist atmosphere, affording a dynamics-based parameterization of MSE diffusivity. The implementation of the parameterization in an EBM leads to an interactive MSE diffusivity that accounts for the midlatitude eddy response to climate forcing perturbations. Under a uniform radiative forcing, the EBM with a diffusivity so parameterized produces a weakening of the midlatitude diffusivity and a modestly polar-amplified surface temperature response as an inevitable outcome under the dual constraints of the nonlinear Clausius–Clapeyron relation and the temperature gradient-dependent diffusivity, even in the absence of any poleward-amplifying radiative feedbacks. As the consequence of more isothermal temperature and reduced diffusivity, the variance of the midlatitude surface temperature also decreases with warming.

Wall-attached temperature structures in supersonic turbulent boundary layers

It is well known that low- and high-speed velocity streaks are statistically asymmetric. However, it is unclear how different the low- and high-temperature structures (T-structures) are even though they are strongly coupled with the streamwise velocity. Therefore, this paper identifies three-dimensional wall-attached temperature structures in supersonic turbulent boundary layers over cooled and heated walls (coming from direct numerical simulations) and separates them into positive and negative families. Wall-attached T-structures are self-similar; especially, the length and width of the positive family are linear functions of the height. The superposed temperature variance in both positive and negative families exhibits a logarithmic decay with the wall distance, while the superposed intensity of the wall-normal heat flux in the negative family shows a logarithmic growth. The modified strong Reynolds analogy proposed by Huang, Coleman, and Bradshaw [“Compressible turbulent channel flows: DNS results and modelling,” J. Fluid Mech. 305, 185–218 (1995)] is still valid in the negative family. The relative position between T-structures of opposite signs depends on the wall temperature and that in the cooled-wall case differs significantly from the relative position between low- and high-speed streaks, especially those tall ones. In the cooled-wall case, although positive temperature fluctuations below and above the maximum of the mean temperature can cluster to large-scale wall-attached structures, they are very likely dynamically unrelated.

Robustness of Reduced-Order Jet Noise Models

Three statistical jet noise prediction models are compared for a representative set of single-stream jet cases, which include cold and hot jets of the Strategic Investment in Low-Carbon Engine Technology experiment at an acoustic Mach number of 0.875 as well as the cold jets of the NASA small hot jet acoustic rig experiment at acoustic Mach numbers of 0.5 and 0.9. The implemented models are those proposed by Tam and Auriault (Jet Mixing Noise from Fine-Scale Turbulence,” AIAA Journal, Vol. 37, No. 2, 1999, pp. 145–153), Khavaran and Bridges (“An Empirical Temperature Variance Source Model in Heated Jets,” NASA TM 2012-217743, 2012), and the Goldstein’s “A Generalized Acoustic Analogy,” Journal of Fluid Mechanics, Vol. 488, July 2003, pp. 315–333) generalized acoustic analogy (GAA) model. By virtue of reduced-order modeling, which is based on the single-point mean flow and turbulence statistics, all of these implementations use a number of empirical dimensionless source parameters for far-field noise spectra predictions. In comparison with the Tam and Auriault model, the Khavaran and GAA model implementations use several dimensionless parameters, which are available from previous literature and assumed to be more or less universal for a class of single-stream jets. These parameters include the fluctuating enthalpy function and the dimensionless amplitudes of autocovariances of turbulent fluctuating stresses and velocities available from the literature. The comparison of the three models is aimed at not only assessing their accuracy for a range of jet conditions, observer angles, and frequencies but also to examine their robustness outside of a reference jet experiment for which their source models were calibrated. For the input to each model, the mean flow, turbulence kinetic energy, and dissipation rate extracted from Large Eddy Simulations and Reynolds-averaged Navier–Stokes solutions are considered.

Research on equivalent thermal network modeling for rare-earth giant magnetostrictive transducer

Of crucial importance for giant magnetostrictive transducers (GMTs) design is to quickly and accurately analysis the temperature distribution. With the advantages of low calculation cost and high accuracy, thermal network modelling has been developed for thermal analysis of GMT. However, the existing thermal models have their limits to describe these complicated thermal behaviors in the GMTs: most of researches focused on steady-state which is incapable of capturing temperature variances; the temperature distribution of giant magnetostrictive (GMM) rods is generally assumed to be uniform whereas the temperature gradient on the GMM rod is remarkable due to its poor thermal conductivity; the non-uniform distribution of GMM’s losses is seldom introduced into thermal model. Therefore, a transient equivalent thermal network (TETN) model of GMT is established in this paper, considering the aforementioned three aspects. Firstly, based on the structure and working principle of a longitudinal vibration GMT, thermal analysis was carried out. Following this, according to the heat transfer process of GMT, the TETN model was established and the corresponding model parameters were calculated. Finally, the accuracy of the TETN model for the temporal and spatial analysis of the transducer temperature are verified by simulation and experiment.

Impact of tundra vegetation type on topsoil temperature in central Spitsbergen (Svalbard, High Arctic)

Current climatic models and projections forecast further increases in air temperature in the Arctic in the future. Therefore, new knowledge concerning the variability of air and soil temperature as well as its dependence on environmental factors is urgently needed to better understand and forecast the consequences of climate warming in the Arctic region. The main aims of this study were: 1) to determine the variability of the topsoil temperature for the one-year time scale under different types of tundra vegetation in the Adventdalen Valley in the central part of Spitsbergen (Svalbard, High Arctic), and 2) to determine the impact of different types of tundra vegetation on the topsoil temperature on a microscale in this area. The obtained results indicate that wet sites covered with marsh and moss tundra vegetation exhibited a significantly higher mean annual topsoil temperature (−0.7 °C and −1.2 °C, respectively) than sites featuring bare ground (−1.5 °C), Arctic meadow (−2.1 °C), and heath tundra vegetation (−2.4 °C). The mean topsoil temperature during the summer season was the lowest at sites covered with Arctic meadow and heath tundra vegetation (4.9 °C and 5.7 °C, respectively), and highest at the site with bare ground (6.9 °C). The topsoil temperature was highly and significantly correlated with the air temperature (correlation coefficient between 0.86 and 0.92); however, the correlation was clearly higher during the autumn and summer seasons (correlation coefficient between 0.76 and 0.89; p < 0.001) in comparison with the winter season (correlation coefficient between 0.67 and 0.89; p < 0.001) and especially the spring season (correlation coefficient between 0.62 and 0.71; p < 0.001). Freeze-thaw events were substantially less frequent in the topsoil (up to 16 events) compared to the atmosphere (at least 80 events), and their number was clearly different even at the microscale (from 4 to 16 events). Local microtopography, snow cover, tundra vegetation type, soil properties, and soil moisture were responsible for variances in topsoil temperature and number of freeze–thaw events. The obtained results indicated that the topsoil temperature is significantly different, even at the microscale, and further research is needed in other Arctic terrestrial environments to better understand and forecast the consequences of climate warming in this region of the world.

Transitional fluctuations of thermal boundary layer in horizontal convection

Fluctuations of thermal boundary layer (BL) in horizontal convection (HC) strongly affect the global heat transport through the HC sample and predominately determine the flow state. Here, we present a systematic experimental study of vertical profiles of mean temperature and temperature variance in the thermal BL of a HC flow that are heated and cooled from the bottom. Three rectangular HC samples filled with de-ionised water are used in the experiment. They have the same aspect ratios Γ≡L:W:H=10:1:1 but with different L (L, W and H are, respectively the length, width and height of the sample). The Rayleigh number Ra varies in the range 2×1010≲Ra≲1.3×1013, and the Prandtl number Pr is in the range 3.9≲Pr≲6.5. For all Ra in the studied range, we find that the cold thermal BL above the cooling plate remains laminar and the vertical profiles of measured mean temperature follow a universal scaling form predicted for laminar BL by Yan, Shishkina and He (J. Fluid Mech., vol. 915, 2021, R5). Above the heated plate, on the contrary, temperature fluctuations in the hot thermal BL undergo several transitional changes as Ra increases. For Ra≲6×1010, the thermal BL has a stable double-layer structure agreeing with the predicted scaling form for laminar BL and the temperature fluctuations are nearly zero. In the range 6×1010≲Ra≲1.1×1011, temperature fluctuations inside the BL have intermittent decayed oscillations, which results in deviations of the measured mean temperature profiles from the predicted scaling form. For 1.1×1011≲Ra≲1012, the temperature oscillations inside the BL become continuous and stable. Correspondingly, an intermediate layer emerges in the thermal BL, where the mean temperature profile has a sinusoidal variation on the distance z above the heated plate. For 1012≲Ra≲1.3×1013, the temperature fluctuations in the intermediate layer become irregular and intermittent, indicating a growing mixing intensity as Ra increases. When Ra exceeds 7×1012, the vertical distribution of mean temperature in the intermediate layer is uniform because of strong mixing. The temperature-variance vertical profiles follow a power-law function σT2(z)∼z−γ with the exponent γ=0.66, which agrees with the Priestley prediction for thermal convection over a heated horizontal surface. Our results thus reveal a series of transitional changes of temperature fluctuations, from laminar to chaotic states, in the hot thermal BL. They predominately account for the enhancement of global heat transport in the HC flow observed by Reiter and Shishkina (J. Fluid Mech., vol. 892, 2020, R1).

A classification of nonequilibrium steady states based on temperature correlations

Although generalized ensembles have now been in use in statistical mechanics for decades, including frameworks such as Tsallis’ nonextensive statistics and superstatistics, a classification of these generalized ensembles outlining the boundaries of validity of different families of models, is still lacking. In this work, such a classification is proposed in terms of supercanonical and subcanonical ensembles, according to a newly defined parameter, the inverse temperature covariance parameter U. This parameter is non-negative in superstatistics (and is equal to the variance of the inverse temperature) but can be negative for other families of statistical ensembles, acquiring then a broader meaning. It is shown that U is equal for every region of a composite system in a steady state, and examples are given of supercanonical and subcanonical states.

The high-energy probability distribution of accretion disc luminosity fluctuations

ABSTRACT The probability density function of accretion disc luminosity fluctuations at high observed energies (i.e. energies larger than the peak temperature scale of the disc) is derived, under the assumption that the temperature fluctuations are lognormally distributed. Thin disc theory is used throughout. While lognormal temperature fluctuations would imply that the disc’s bolometric luminosity is also lognormal, the observed Wien-like luminosity behaves very differently. For example, in contrast to a lognormal distribution, the standard deviation of the derived distribution is not linearly proportional to its mean. This means that these systems do not follow a linear rms-flux relationship. Instead they exhibit very high intrinsic variance, and undergo what amounts to a phase transition, in which the mode of the distribution (in the statistical sense) ceases to exist, even for physically reasonable values of the underlying temperature variance. The moments of this distribution are derived using asymptotic expansion techniques. A result that is important for interpreting observations is that the theory predicts that the fractional variability of these disc systems should increase as the observed frequency is increased. The derived distribution will be of practical utility in quantitatively understanding the variability of disc systems observed at energies above their peak temperature scale, including X-ray observations of tidal disruption events.

Maxwell Nanofluids: FEM Simulation of the Effects of Suction/Injection on the Dynamics of Rotatory Fluid Subjected to Bioconvection, Lorentz, and Coriolis Forces.

In this study, the relevance of Lorentz and Coriolis forces on the kinetics of gyratory Maxwell nanofluids flowing against a continually stretched surface is discussed. Gyrotactic microbes are incorporated to prevent the bioconvection of small particles and to improve consistency. The nanoparticles are considered due to their valuable properties and ability to enhance thermal dissipation, which is important in heating systems, advanced technology, microelectronics, and other areas. The main objective of the analysis is to enhance the rate of heat transfer. An adequate similarity transformation is used to convert the primary partial differential equations into non-linear dimensionless ordinary differential equations. The resulting system of equations is solved using the finite element method (FEM). The increasing effects of the Lorentz and Coriolis forces induce the velocities to moderate, whereas the concentration and temperature profiles exhibit the contrary tendency. It is observed that the size and thickness of the fluid layers in the axial position increase as the time factor increases, while the viscidity of the momentum fluid layers in the transverse path decreases as the time factor decreases. The intensity, temperature, and velocity variances for the suction scenario are more prominent than those for the injection scenario, but there is an opposite pattern for the physical quantities. The research findings are of value in areas such as elastomers, mineral productivity, paper-making, biosensors, and biofuels.

Sensing of ocean mixing via forward scattering acoustic scintillation

Ocean mixing process observations show complex spatio-temporal patterns as well as energy and dissipation levels that vary over six or more orders of magnitude, creating a challenging sampling problem. Acoustic imaging of ocean turbulent structures is informative, but extraction of quantities like spectra and dissipation rates of kinetic energy, ε, and temperature variance, Χ, requires geometric sampling constraints. Here, a remote sensing approach is proposed in the spirit of Di Iorio and Farmer (1994), and Duda et al. (1988), based on weak multiple-forward scattering physics. In the correct scattering regime, observations of the wavenumber spectrum of acoustic intensity obtained on a vertical array gives a direct measure of the range average turbulence index of the refraction spectrum in a plane transverse to the acoustic path. In this talk, the theory will be reviewed and some illustrative simulations will be presented; importantly, one-way acoustic transmission measures a combination of both ε and Χ. Experimental arrangements (frequency/range) where the theory is expected to apply will be outlined with an eye towards observing bottom boundary layer mixing. With a suitable vertical array, one could resolve scales from the smallest internal waves (∼several meters), through the transition regime, and down to scales of turbulence (∼tens of cm).

Chroma consistency and luminous efficacy for a WLED using remote phosphor configuration with a tri-layer design

The light quality of white-light-emitting diodes (WLEDs), an essential element for the improvement of WLEDs performance, can now be estimated by the angular color uniformity (ACU). In this study, a single micro-patterned layer is used to compare the variations between the traditional remote phosphor (RP) layer and the remote phosphor layer (single remote micro-patterned phosphor film (RMPP) layer). Furthermore, we investigate the application of a novel triple remote phosphor layer to improve the ACU in RP down-light lamps. Besides, the optical efficiency of the layers as well as the distribution for the angular correlated color temperature (ACCT) were also measured experimentally. According to the findings, the dual-RMPP-layer structure can achieve better chromatic uniformity with just 441 K of correlated color temperature (CCT) variance. Meanwhile, the single RMPP layer shows an ACCT deviation of 556 K and RP film structure of 1390 K. The simulation incorporating e finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in ACU. Furthermore, compare to the traditional RP layer, the single and dual RMPP layers configuration result in respective luminous efficiency ameliorations of 6.68% and 4.69%. The scattering principle and combining influence from the micro-molded layer may explain the enhancement in ACU as well as lumen.

Using triple-layer remote phosphor structures LaVO4:Eu3+ and ZnS:Cu,Sn to improve the chromatic uniformity and luminous quality of WLEDs

This research paper investigates the novel triple remote phosphor layer for improving the remote phosphor’s angular chroma uniformity (ACU) of down-light lamps by using remote micro-patterned phosphor layers (RMPP). In addition, introducing the triple-layer (TL) RMPP is introduced to offer the potential approach to this objective. This analysis also measures the optical efficiency of the layers and the angle distribution of angular correlated color temperature (ACCT). Drawing a comparison between the traditional dual-layer (DL) RMPP and the proposed TL is furthermore critical to this study. According to the findings, the triple-layer phosphor configuration can achieve greater hue consistency while having a correlating colour temperature (CCT) variance merely measured at 441 K. Results in the single RMPP layer are 1390 K of the remote phosphor (RP) sheet setting and 556 K for the ACCT deviation. The recreation employing finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in angular color uniformity (ACU). The structure of DL and TL RMPPs results in a 6.68 % and 4.69 % gain in luminous efficiency, respectively, with the standard RMPP layer at a currently driving of 350 mA. The micro-patterned layer’s scattering characteristic and mixing effect may account for the increased ACU and luminous efficiency.

The Horizontal Wavelength Spectrum of Gravity Wave Activity in Mars’s Lower Atmosphere: The Perspective from MGS–TES Nadir Observations

Connecting upper-atmospheric gravity waves (GW) to their lower- and middle-atmospheric (0–30 and 30–100 km altitude) origins can improve understanding of the evolution of Mars’s atmosphere as well as its present thermal structure and general circulation. A recent study using observations from the Mars Climate Sounder (MCS) on board the Mars Reconnaissance Orbiter (MRO) characterized the climatology of lower-atmospheric GW with 10–100 km horizontal wavelengths, but GW observed in the upper atmosphere have horizontal wavelengths of up to 500 km, motivating more careful attention to the horizontal wavelength spectrum of lower-atmospheric GW. A previous study of observations by the Thermal Emission Spectrometer (TES) on Mars Global Surveyor (MGS) reported substantial interannual variability in the horizontal wavelength spectrum of wave activity defined broadly, including GW. Here, we derive the horizontal wavelength spectrum of wave activity from the brightness temperature variance spectrum of MGS–TES observations resampled to the MRO–MCS spectral channels during L s = 120°–150°, Mars Years 24 and 25. Lower-atmospheric wave activity is strongest at wavelengths <200 km, a population which resembles that observed by MRO–MCS and is likely GW activity. This short-wavelength population is distinct from a wave population with wavelengths >1000 km, which appears to be a mixture of tides and planetary waves. We find that interannual variability in GW activity previously identified using MGS–TES data largely arises from a change in the instrumental noise characteristics of MGS–TES during the first quarter of MY 25.

Feasibility, Acceptability, and Performance of a Continuous Temperature Monitor in Older Adults and Staff in Congregate-Living Facilities.

Residents of congregate-living facilities are susceptible to disability and mortality from infection given the presence of advanced age, multimorbidity, and frailty-as demonstrated in the recent COVID pandemic. This study assessed the feasibility, acceptability, and applicability of a continuous temperature monitoring device in a congregate-living facility with residents of independent living, assisted living, and their care-providing staff. We hypothesized that a wearable device compared with daily manual temperature assessment would be well tolerated and more effective at detecting temperature variances than current standard of care body temperature assessment. Feasibility study. Residents of assisted and independent living and staff of a retirement community. Thirty-five participants, including residents in assisted- and independent-living facilities (25) and staff (10) were enrolled in a 90-day feasibility study and wore a continuous temperature sensor from March to July 2021. Primary outcomes included study completion, ability to reapply the sensor, temperature data acquisition, and data availability from the sensors. A secondary analysis of the temperature data involved comparing the method of obtaining temperature using the continuous monitoring device against standard of care using traditional manual thermometers. Overall, 91.3% of residents, who were in the study during the first reapplication, were able to apply the device without assistance (21 of 23), and 80% of resident participants completed the study (20 of 25). For staff participants, completion rates and reapplication rates were 100%. Data acquisition rates from the continuous temperature devices were much higher than manual temperatures. Four episodes of fever were detected by the devices; manual temperature checks did not identify these events. Continuous temperature monitoring in an older adult population and the staff in congregate-living facilities is feasible and acceptable. This approach identified fever undetected by current standard of care indicating the capability of this device for earlier detection of fevers.

Modeling the spatiotemporal heterogeneity of land surface temperature and its relationship with land use land cover using geo-statistical techniques and machine learning algorithms.

Rapid changes in land use and land cover (LULC) have ecological and environmental effects in metropolitan areas. Since the 1990s, Saudi Arabia's cities have undergone tremendous urban growth, causing urban heat islands, groundwater depletion, air pollution, loss of ecosystem services, etc. This study evaluates the variance and heterogeneity in land surface temperature (LST) because of LULC changes in Abha-Khamis Mushyet, Saudi Arabia, from 1990 to 2020. The research aims to determine the impact of urban biophysical parameters on the High-High (H-H) LST cluster using geospatial, statistical, and machine learning techniques. The support vector machine (SVM) was used to map LULC. The land surface temperature (LST) has been derived using the mono-window algorithm (MWA). The local indicator of spatial associations (LISA) model was implemented on the spatiotemporal LST maps to identify LST clusters. Also, the parallel coordinate plot (PCP) approach was employed to examine the relationship between LST clusters and urban biophysical variables as a proxy of LULC. LULC maps show that urban areas rose by > 330% between 1990 and 2020. Built-up areas had an 83.6% transitional probability between 1990 and 2020. In addition, vegetation and agricultural land have been transformed into built-up areas by 17.9% and 21.8% respectively between 1990 and 2020. Uneven LULC changes in terms of built-up areas lead to increased LST hotspots. High normalized difference built-up index (NDBI) was linked to LST hotspots but not normalized difference water index (NDWI) or normalized difference vegetation index (NDVI). This research could help policymakers develop mitigation strategies for urban heat islands.