Absolute Surface Temperature Research Articles

The Role of Renewable-Derived Plastics in the Analysis of Waste Management Schemes: A Time-Dependent Carbon Cycle Assessment

Carbon capture and storage (CCS) is an essential greenhouse gas removal (GGR) technology used to achieve negative emissions in bioenergy plants using biomass feedstock (Bio-CCS). In this study, the climate mitigation potential of a novel GGR technology consisting in the production of renewable-derived plastics from municipal solid waste (MSW) refuse has been evaluated. This novel GGR technology allows for carbon storage, for variable periods, in stable materials (plastics), and thus overcomes the technical limitations of CCS. A time-dependent carbon cycle assessment has been conducted based on the Absolute Global surface Temperature change Potential (AGTP) metric. This new method to assess carbon emissions is presented against a traditional life cycle assessment (LCA). The production of renewable-derived plastics proves to be an effective GGR technology for both landfill- and incineration-dominant countries in Europe. The results obtained encourage the implementation of renewable-derived plastics in Integrated Assessment Models (IAMs) to assess their global potential in forecasting scenarios to achieve the ambitious climate change targets set in the European Union. Thanks to this study, a novel approach toward a green and sustainable economy has been established. This study will help to fill the gaps between bioenergy and renewable materials production.

Example of a solution for Dorodnitzyn’s limit formula

In the present paper, we show an example of a solution for Dorodnitzyn’s gaseous boundary layer limit formula. Oleinik’s no back-flow condition ensures the existence and uniqueness of solutions for the Prandtl equations in a rectangular domain R⊂R2. It also allowed us to find a limit formula for Dorodnitzyn’s stationary compressible boundary layer with constant total energy on a bounded convex domain in the plane R2. Under the same assumption, we can give an approximate solution u for the limit formula if |u|<<<1 such that: u(z)≅δ∗c∗z+625⋅12i0⋅4U23z4+o(z5),that corresponds to an approximate horizontal velocity component when a small parameter ϵ given by the quotient of the maximum height of the domain divided by its length tends to zero. Here, c>0, δ is the boundary layer’s height in Dorodnitzyn’s coordinates, U is the free-stream velocity at the upper boundary of the domain, and T0 is the absolute surface temperature.

Improving temperature reconstructions from ice-core water-isotope records

Abstract. Oxygen and hydrogen isotope ratios in polar precipitation are widely used as proxies for local temperature. In combination, oxygen and hydrogen isotope ratios also provide information on sea surface temperature at the oceanic moisture source locations where polar precipitation originates. Temperature reconstructions obtained from ice-core records generally rely on linear approximations of the relationships among local temperature, source temperature, and water-isotope values. However, there are important nonlinearities that significantly affect such reconstructions, particularly for source region temperatures. Here, we describe a relatively simple water-isotope distillation model and a novel temperature reconstruction method that accounts for these nonlinearities. Further, we examine in detail many of the parameters, assumptions, and uncertainties that underlie water-isotope distillation models and their influence on these temperature reconstructions. We provide new reconstructions of absolute surface temperature, condensation temperature, and source region evaporation temperature for all long Antarctic ice-core records for which the necessary data are available. These reconstructions differ from previous estimates due to both our new model and reconstruction technique, the influence of which is investigated directly. We also provide thorough uncertainty estimates for all temperature histories. Our reconstructions constrain the pattern and magnitude of polar amplification in the past and reveal asymmetries in the temperature histories of East and West Antarctica.

Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks.

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

Molecular paleothermometry of the early Toarcian climate perturbation

Abstract In this paper, we use molecular paleothermometry, based on the TEX86 proxy derived from fossilized archaeal lipids, to reconstruct absolute sea surface temperatures (SSTs) for the northwest Tethys Shelf during the late Pliensbachian to early Toarcian (Early Jurassic, ~183 Ma) stages. Our composite record from outcrops in Spain and Italy reveals that tropical SSTs varied between 22 and 32 °C over a ~ 3 Myr time period, including transient temperature excursions of 5–10 °C magnitude with lapse rates of ~0.1 °C/kyr. Changes in reconstructed SSTs covaried with sea level fluctuations and δ18O isotope signatures of marine biocalcifiers, recording recurrent shifts between icehouse and greenhouse states. Parallel trends of reconstructed SST and δ13C isotopes of atmospheric CO2 may reflect storage of isotopically light carbon in cryosphere reservoirs during icehouse phases and release during greenhouse phases. The existence of a labile cryosphere is considered a prerequisite to explain the inferred rapid climate fluctuations and as a reservoir to facilitate pronounced carbon isotope excursions.

An ITER Challenge Absolute Surface Temperature Measurements of Low and Varying Emissivity Tungsten Plasma-Facing Components

One of the challenges that International Thermonuclear Experimental Reactor (ITER) will face during plasma operation is to determine the absolute divertor surface temperature of the actively water-cooled (70 °C, 3 MPa) tungsten plasma-facing units (PFUs) to ensure their integrity. The expected steady-state heat flux up to 10 MW/m2 is close to the operational limit and so one of the goals of the thermographic system is to make reliable measurements (wavelength band: 3.5– $4.5~\mu \text{m}$ ) with relatively low error bars to avoid tungsten melting and material damages. The tungsten emissivity is low and dependent on wavelength, temperature, and surface state (roughness, cracks, oxidation, and erosion/deposition processes) which can evolve during the time along with plasma operation. An error on the absolute emissivity can lead to large absolute temperature errors, and consequently to either a reduction of the operational window to fulfill safety limits, or an increased risk regarding the integrity of the components. For the past years, a number of emissivity measurements have been performed with ITER-like PFU mock-ups made of different grades of tungsten, with different techniques, from different material makers, and from different manufacturers. The overall emissivity discrepancy is large, indicating that tungsten emissivity is a major issue for temperature measurement and wall protection. The accuracy of the temperature measurement is investigated for both monocolor and bicolor IR thermography techniques. We present laboratory tests performed with an IR camera equipped with a rotating filter wheel for bicolor temperature measurement. It shows that the bicolor technique can reach high precision $\Delta \text {T}/\text {T} at high temperature assuming the emissivity ratio is constant regarding the two selected wavelengths.

An Approach for the Retrieval of Land Surface Temperature from the Industrial Area Using Landsat-8 Thermal Infrared Sensors

The thermal imagine provides data with synoptic coverage for investigating thermal information from hot sources for detecting, mapping energy loss from the industrial area. This study attempts to retrieved heat loss from the industrial area using Landsat-8 TIRS experimented at an industrial area of Pasir Gudang, Peninsular Malaysia, the main objective is to investigate the sensitivity of Landsat-8 TIR for detecting industrial thermal energy within the various range of targets of different temperatures. An estimated heat map with absolute surface temperature values is the final output. Apart of the pre-processing of Landsat-8 TIRS data, data are processed for the retrieval of land surface temperature, then subjected to a downscaling process to final 30 x 30 m pixels, hence enable to merge with all Landsat-8 bands for visualization and validation of results. The split window algorithm (SWA) is used for the temperature retrieval from band 10 and 11, with other driven parameters. The Multiple Adaptive Regression Splines (MARS) model for spatial downscaling was adopted in this study. The generated thermal energy map was then validated over selected targets in the field and compared to corresponding downscaled MODIS LST product (MODIS11A2). TIR bands applied with SWA generated 13.7°C temperature dynamic range from 22.35˜51.36° C in comparison with MODIS LST product values range from 27.17 ˜ 37.65°C). Results indicated good agreement between the generated thermal energy map with the in-situ validations (RMSE=0.43 °C). It is therefore concluded that derived Land surface temperature map derived is suitable for study industrial thermal environment at 1:50,000 ˜ 100,000 scales, adequately to be used for environmental impact assessment.

Automated water surface temperature retrieval from Landsat 8/TIRS

Satellite remote sensing of Land and Water Surface Temperature (L/WST) has many applications in studies of terrestrial and aquatic ecology. Retrieval of L/WST requires a well calibrated radiometer and an accurate atmospheric correction. In the present study, the performance of the Thermal InfraRed Sensor (TIRS) on board Landsat 8 is evaluated for the retrieval of L/WST. libRadtran is used to retrieve atmospheric correction parameters based on atmospheric profiles of relative humidity and temperature from three global atmospheric models. Performance of single band retrievals is compared to typical MODTRAN results from the Atmospheric Correction Parameter Calculator (ACPC) and a split-window approach. A multi-temporal land masking method using imagery from the Operational Land Imager (OLI) on board Landsat 8 is demonstrated, and is used to automatically classify imagery in the matchup dataset in three classes of cloud cover. Two sources of in situ data covering the Belgian Coastal Zone (BCZ) are used for validation of the L/WST product: (1) fixed locations in the Flemish Banks measurement network and (2) underway data from regular RV Belgica campaigns. In the present study the single band methods outperformed the split-window approach, and consistent retrievals are found for the MODTRAN and libRadtran simulations. Typical single band surface temperature retrievals in quasi cloud-free conditions have Root Mean Squared Differences (RMSD) of 0.7 K and 1 K for Bands 10 and 11 with low bias, depending on the method and atmospheric profile source. For imagery with scattered clouds, RMSD values increase to 1 K and 2 K respectively with an approximately 0.5 K cold bias, likely caused by cloud proximity. The calibration efforts combined into Collection 1 allows for accurate absolute surface temperature retrievals from B10 on Landsat 8/TIRS for homogeneous targets with known emissivity, such as liquid water. The method is adapted to global processing and can be used for Land Surface Temperature retrieval with a suitable source of emissivity data.

Thermally induced icequakes detected on blue ice areas of the East Antarctic ice sheet

ABSTRACTOver a year of seismic observations, ~5000 short duration icequakes were detected by a permanent broadband station installed at the Princess Elisabeth base, located ~180 km inland in eastern Dronning Maud Land, East-Antarctica. Icequake detection via seismic waveform pattern recognition indicates the presence of two dominating clusters of events, totalizing ~1500 icequakes. The corresponding icequake locations point towards two distinct zones of outcropping blue ice areas (BIAs) located respectively at 4 and 1 km from the seismic station, both on the leeward side of a nunatak protruding through the ice sheet. The temporal occurrence of these icequakes suggests a close genetic link with thermal contraction of ice caused by significant surface cooling controlled, in summer by variations in diurnal solar radiation and in winter by strong cooling during cold katabatic regimes. Further analysis demonstrates the dependence of these icequakes on the absolute surface temperature and on its temporal change. Besides providing information on the ice fracture mechanics and rheology, investigations of thermal icequakes may be regarded as a ground-based proxy for the monitoring of the thermal state of BIAs, and characterization of ice-sheet ablation zones.

Commingled black and white cows (Bos taurus; Angus and Charolais) in high-elevation rangeland are differentially parasitised by Haematobia irritans

Globally horn flies (Haematobia irritans) are one of the most economically damaging parasites of beef cattle. These obligate blood-feeding external parasites take blood meals from cattle leading to blood loss, annoyance avoidance behaviours, and reductions in animal performance. Development of chemical resistance by horn flies suggests that novel management strategies are needed. More in-depth understanding of parasitism relative to hide colour and temperature, especially in a changing climate, may enhance animal production. In peak parasitism periods of 2016 and 2017, we measured horn fly loads on commingled black Angus and white Charolais cows in a cold high-elevation rangeland in Wyoming, USA. We tested how breed, year, and interactions explained horn fly parasitism and economic thresholds. In 2016 we also measured ambient and external cow temperatures to further elucidate thermal ecology mechanisms explaining horn fly hide colour preferences. Mean annual horn fly infestations were always four times greater or more on black cows than white cattle both years, but not all cattle reached economic thresholds all years and the breed by year interaction was not significant. Difference in horn fly preference for black cattle over white cattle in our cold high-elevation environment may be explained by greater absolute and relative external surface temperatures of black hided cows. Host colour and thermal preferences of horn flies could be incorporated into integrated pest management strategies that only treat darker hided cattle and producers in cold high-elevation environments conduct real-time monitoring to determine if treatments are even needed on a year-by-year basis.

Non-invasive measurement of effective thermal conductivity of human skin with a guard-heated thermistor probe

This paper describes a non-invasive method for measurement of the effective thermal conductivity of human skin with a guard-heated thermistor probe. The guard-heated thermistor probe makes it possible to accurately measure the absolute surface temperature of a material at temperatures higher than the ambient temperature. In this study, the probe was used for a non-invasive measurement of the effective thermal conductivity of human skin by measuring skin surface temperature response for a short time. The effective thermal conductivity of human skin was measured at different body locations, such as cheeks, forearms, and heels, on five healthy volunteers. The measured values reflect the effects of multi-layered skin structure and biological processes, such as blood perfusion and metabolism beneath the skin. The results reveal a correlation between the effective thermal conductivity and the skin structure. A numerical simulation was performed to assess the effects of the epidermis thickness and the thermal conductivities of skin layers on the effective thermal conductivity of human skin. The results show that the thickness of the epidermis has a large impact on the effective thermal conductivity measured with a guard-heated thermistor probe. This is because the measured effective thermal conductivity is a function of the thermal conductivities of both the epidermis and dermis, depending on the thermal penetration depth during measurement. At locations on the body with a thicker epidermis, such as the heel, the epidermal thermal conductivity dominates over the effective thermal conductivity. At locations on the body with a thinner epidermis, such as the cheek and forearm, the dermal thermal conductivity dominates over the effective thermal conductivity. The influences of physiological conditions, such as blood perfusion beneath the skin and metabolism, on the effective thermal conductivity of human skin, were also analyzed numerically. Variations in the blood perfusion rate and metabolic heat generation rate of the dermis layer were found to have a slight impact on the effective thermal conductivity; however, only the blood perfusion rate and the arterial blood temperature were found to influence the skin surface temperature.

Calibration procedures of the Tore-Supra infrared endoscopes

Five endoscopes equipped with infrared cameras working in the medium infrared range (3–5μm) are installed on the controlled thermonuclear fusion research device Tore-Supra. These endoscopes aim at monitoring the plasma facing components surface temperature to prevent their overheating. Signals delivered by infrared cameras through endoscopes are analysed and used on the one hand through a real time feedback control loop acting on the heating systems of the plasma to decrease plasma facing components surface temperatures when necessary, on the other hand for physics studies such as determination of the incoming heat flux . To ensure these two roles a very accurate knowledge of the absolute surface temperatures is mandatory. Consequently the infrared endoscopes must be calibrated through a very careful procedure. This means determining their transmission coefficients which is a delicate operation. Methods to calibrate infrared endoscopes during the shutdown period of the Tore-Supra machine will be presented. As they do not allow determining the possible transmittances evolution during operation an in-situ method is presented. It permits the validation of the calibration performed in laboratory as well as the monitoring of their evolution during machine operation. This is possible by the use of the endoscope shutter and a dedicated plasma scenario developed to heat it. Possible improvements of this method are briefly evoked.

Evaluating the impact of adjusting surface temperature derived from Landsat 7 ETM+ in crop evapotranspiration assessment using high-resolution airborne data

ABSTRACTSurface temperature (Ts) is an essential parameter in many land surface processes. When Ts is obtained from remotely sensed satellite data the consideration of atmospheric correction may be needed to obtain accurate surface temperature estimates. Most atmospheric correction methods adjust atmospheric transmissivity, path radiance and downward thermal radiation coefficients. Following a standardized atmospheric correction of Landsat 7 thermal data, some differences were found between these corrected data and surface temperature derived from very-high resolution airborne thermal data. Five different methods for determining atmospheric correction were evaluated comparing atmospherically corrected Landsat 7 data with airborne data for an area of olive orchards located at Southern Spain. When using standard default Landsat 7 calibration coefficients Ts differences between satellite and airborne observations ranged from 1 to 6 K, highlighting the need to perform more robust atmospheric correction. When applying the customized values for semi-arid temperate climate in Idaho, USA, and the values based on the National Centers for Environmental Prediction (NCEP) Ts differences ranged from 1 to 4 K, indicating that additional local calibration may be appropriate. Optimal coefficients were determined using the Generalized Reduced Gradient (GRG) approach, a nonlinear algorithm included in Solver tool, obtaining Ts differences around 1–3 K. In order to evaluate the impact of considering the proposed correction approaches, assessment of the evapotranspiration and crop coefficient values derived from the Mapping Evapotranspiration with Internalized Calibration (METRIC) energy balance model provided maximum errors of around 4%, indicating that the METRIC model does not require a robust atmospheric correction. However, the localized calibration approaches are proposed as useful alternatives when absolute land surface temperatures values are required, as in the case of the determination of crop water stress based on differences between canopy (Tc) and air temperature (Tair).

Surface energy fluxes in the Northeast Asia ecosystem: SEBS and METRIC models using Landsat satellite images

The reliable assessment of turbulent heat fluxes and evapotranspiration (ET) from the field to regional scales is fundamental to comprehending land-atmosphere interactions and water balance dynamics. In this study, we evaluated two single-source operational methodologies, the Surface Energy Balance System (SEBS) and Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC), to scrutinize the surface energy balance components using Landsat TM/ETM+ images collected between 2002 and 2013. Estimations from the models were compared with ground observations from two grassland and two cropland AsiaFlux tower sites. To examine model behaviors adequately, both SEBS and METRIC were parameterized using the same predictions of instantaneous and daily net radiation (RN). The RN estimations were quite promising; the ensemble averaged (from all sites) bias and root mean square error (RMSE) were within 39Wm−2. In terms of the soil heat flux (G) and sensible heat flux (H), both models showed various contrasted outputs at the tower and spatial scales, yielding a maximum difference of 77Wm−2. The estimated G from the albedo-based method (METRIC) had low bias and RMSE within 46Wm−2, whereas that obtained from the fractional vegetation cover based method (SEBS) exceeded 125Wm−2. However, the SEBS model performed better for H estimations, yielded less bias and an RMSE (averaged) within 82Wm−2, compared with errors of 102Wm−2 obtained from METRIC. The slightly higher errors in METRIC were caused by its original design based on internal calibration, which lumped the maximum biases from other variables into the estimated H. The errors in G (SEBS) were almost equal to the errors in H (METRIC) but of the opposite sign. Because the latent heat flux is calculated as a rest-term, the errors in G and H compensate for each other. Therefore, both models performed similarly in consistently overestimating the latent heat flux (LE) and corresponding daily ET because of energy balance misclosure in the eddy covariance flux measurements. Three different closure approaches [least squares linear regression (REG), Bowen ratio (BR), and residual (RE) correction] were used, and both models had daily ET with less bias and RMSE (averaged) within 0.16mmday−1 and 0.62mmday−1, respectively, using REG. Furthermore, a sensitivity analysis suggested that corrections of radiometric to absolute surface temperature are essentially required only for SEBS, whereas the accurate calibration of cold and hot end-points is important for METRIC implementation. These evaluations promote better understanding of the strengths and weaknesses of both models for mapping the surface energy balance at the regional scale and are a step toward an integrated methodology for a wide range of heterogeneous ecosystems.

Infrared thermography – evaluation of the results reproducibility

Purpose – Infrared thermography is increasingly being used to diagnose pathologies in buildings, such as façade defects. The purpose of this paper is to assess the results reproducibility and the equipment influence on the measurements. To do so, it was defined as case study the assessment of rendering delamination. Design/methodology/approach – Two infrared cameras of different makers were used to detect the presence of defects deliberately created in specimens. The tests were done in the laboratory with a heat source. The defects were detected through a temperature gradient between the zones with and without defect. Findings – With this thermographic imaging, it was possible to identify the defects in the specimen both qualitatively and quantitatively. The results were found to be reproducible in the three cycles performed. The influence of the equipment on the results was of little significance for the quantitative assessment criterion “temperature difference between zones with and without defect”, but for the criterion “absolute surface temperature”, the difference in the results yielded by the two cameras was around 1.8°C. Originality/value – The results suggest that there is reproducibility of the measurements, considering both the qualitative and quantitative approach, when assessing delamination, irrespective of the maker of the equipment used. The influence of the equipment on the results depends on the quantitative assessment criterion used.

Domestic heating from forest logging residues: environmental risks and benefits

The European Union (EU) relies largely on bioenergy to achieve its climate and energy targets for 2020 and beyond. Special focus is placed on utilization of biomass residues, which are considered to cause low environmental impacts.We used the dataset from the latest European Commission document on the sustainability of solid and gaseous biomass (SWD2014 259), complementing those results by: i) designing three pathways for domestic-heat production using forest logging residues, with different combustion technologies; ii) expanding the analysis to include forest carbon stock development with and without bioenergy; iii) using absolute climate metrics to assess the surface temperature response by the end of the century to a bioenergy and a reference fossil system; iv) including multiple climate forcers (well-mixed GHG, near term climate forcers and surface albedo change); iv) quantifying life cycle impacts on acidification, particulate matter emissions and photochemical ozone formation; v) reviewing potential risks for forest ecosystem degradation due to increased removal of residues.Supply-chain GHG savings of the three pathways analysed ranged between 80% and 96% compared to a natural gas system, above the 70% threshold suggested by the EU. However, the climate impact of bioenergy should be assessed by considering also the non-bioenergy uses of the biomass and by including all climate forcers.We calculate the Surface Temperature Response to bioenergy and fossil systems by means of Absolute Global surface Temperature Potential (AGTP) metric. Domestic heating from logging residues is generally beneficial to mitigate the surface temperature increase by 2100 compared to the use of natural gas and other fossil sources. As long as residues with a decay rate in the forest higher than 2.7%*yr−1 are considered as feedstock, investing now in the mobilization of residues for heat production can reduce the temperature increase by 2100 compared to all the fossil sources analysed, both in case of bioenergy as a systemic change or in case of bioenergy as a transitory option.Furthermore, several environmental risks are associated with the removal and use of forest logging residues for bioenergy. These issues concern mostly local air pollution, biodiversity loss and, mainly for stumps removal, physical damage to forest soils.Forest logging residues are not free of environmental risks. Actions promoting their use should consider: (i) that climate change mitigation depends mainly on the decay rate of biomass under natural decomposition and time and rate of technology deployment, (ii) whether management guidelines aimed at protecting long-term forest productivity are in place and (iii) whether proper actions for the management of adverse effects on local air pollution are in place.

Approximation of absolute surface temperature measurements of powder bed fusion additive manufacturing technology using in situ infrared thermography

Additive manufacturing (AM) has several possible advantages over traditional manufacturing including increased design freedom, reduced material usage, and shorter lead-times. A noteworthy capability of AM is the ability to monitor the process during material deposition and interrupt the process during fabrication if necessary. Recently, such monitoring, feedback, and control have been made possible by implementing in situ infrared (IR) thermography in powder bed fusion AM technologies. The purpose of the current research was to investigate the acquisition of absolute surface temperatures using in situ IR imaging of the melted or solid surfaces layer-by-layer during fabrication within an electron beam melting (EBM) system. The thermal camera was synchronized with the system's signal voltages of three synchronized events (pre-heating, melting, and raking) to automatically capture images. To acquire absolute temperature values from the IR images, a calibration procedure was established to determine the solid material's emissivity and reflected temperature or mean radiant temperature of the build chamber, which are necessary input parameters for the IR camera. A blackbody radiator was fabricated via EBM and was used as a tool to determine the emissivity of Ti–6Al–4V (determined to be 0.26 in the temperature range of the current study). Furthermore, a mathematical model was developed to determine the view factors associated with the system's interior (e.g. heat shielding) that were used in calculating the mean radiant temperature of the manufacturing environment (∼342°C). Experimental validation of the model was performed using a thermocouple embedded during fabrication that showed a 3.77% difference in temperature. A temperature difference of ∼366°C (1038°C vs. 672°C) was observed when comparing uncorrected IR temperature data with corrected temperature data. Upon validation of the IR parameters for a melted area, experimentation was conducted to also determine powder emissivity (found to be 0.50). The thermal model presented here can be modified and implemented in other AM technologies for consideration of radiation energy to acquire absolute temperatures of layered surfaces, leading to improved thermal monitoring and control of the fabrication process.

Impacts of Atmospheric Temperature Trends on Tropical Cyclone Activity

Abstract Impacts of tropical temperature changes in the upper troposphere (UT) and the tropical tropopause layer (TTL) on tropical cyclone (TC) activity are explored. UT and lower TTL cooling both lead to an overall increase in potential intensity (PI), while temperature changes at 70 hPa and higher have negligible effect. Idealized experiments with a high-resolution global model show that lower temperatures in the UT are associated with increases in global and North Atlantic TC frequency, but modeled TC frequency changes are not significantly affected by TTL temperature changes nor do they scale directly with PI. Future projections of hurricane activity have been made with models that simulate the recent upward Atlantic TC trends while assuming or simulating very different tropical temperature trends. Recent Atlantic TC trends have been simulated by (i) high-resolution global models with nearly moist-adiabatic warming profiles and (ii) regional TC downscaling systems that impose the very strong UT and TTL trends of the NCEP–NCAR reanalysis, an outlier among observational estimates. The impact of these differences in temperature trends on TC activity is comparable to observed TC changes, affecting assessments of the connection between hurricanes and climate. Therefore, understanding the character of and mechanisms behind changes in UT and TTL temperature is important to understanding past and projecting future TC activity changes. The UT and TTL temperature trends in the NCEP–NCAR reanalysis are unlikely to be accurate and likely drive spuriously positive TC and PI trends and an inflated connection between absolute surface temperature warming and TC activity increases.

Estimation of the absolute surface air temperature of the Earth

Average temperatures for the hemispheres and the globe are generally expressed as anomalies from a base period. Most users of these data and the underlying constituent gridded datasets do not require the values in absolute degrees, but a number of users might require this additional detail. An example group of users are climate modellers, who want to directly compare their simulations with reality in absolute units. Reanalysis datasets offer opportunities of assessing earlier absolute temperature estimates, but until recently their quality over data‐sparse regions of the world was questionable. Here, we assess the latest Reanalysis (ERA‐Interim) which is available from 1979 to the present against earlier direct estimates. Globally averaged ERA‐Interim and the earlier direct estimates of absolute surface temperatures across the world are about 0.55°C different for the 1981–2010 period, with ERA‐Interim cooler. The difference is only 0.29°C for the Northern Hemisphere, but larger at 0.81°C for the Southern Hemisphere. Spatially, the largest differences come from the Polar Regions, particularly the Antarctic.

Time-series modeling and prediction of global monthly absolute temperature for environmental decision making

Abstract A generalized, structural, time series modeling framework was developed to analyze the monthly records of absolute surface temperature, one of the most important environmental parameters, using a deterministicstochastic combined (DSC) approach. Although the development of the framework was based on the characterization of the variation patterns of a global dataset, the methodology could be applied to any monthly absolute temperature record. Deterministic processes were used to characterize the variation patterns of the global trend and the cyclic oscillations of the temperature signal, involving polynomial functions and the Fourier method, respectively, while stochastic processes were employed to account for any remaining patterns in the temperature signal, involving seasonal autoregressive integrated moving average (SARIMA) models. A prediction of the monthly global surface temperature during the second decade of the 21st century using the DSC model shows that the global temperature will likely continue to rise at twice the average rate of the past 150 years. The evaluation of prediction accuracy shows that DSC models perform systematically well against selected models of other authors, suggesting that DSC models, when coupled with other ecoenvironmental models, can be used as a supplemental tool for short-term (∼10-year) environmental planning and decision making.