Atmospheric Band Research Articles

A spectrally selective gap surface-plasmon-based nanoantenna emitter compatible with multiple thermal infrared applications

Wavelength-selective nanoantenna emitters have attracted considerable attention due to their widespread applications ranging from thermal radiation management to thermophotovoltaics. In this paper, we design a wavelength-selective nanoantenna emitter based on the excitation of gap-surface plasmon modes using a metal–insulator–metal configuration (silicon dioxide (SiO2) sandwiched between silver (Ag) layers) for satisfying multiple infrared applications. The proposed design, which is called design I, realizes triple narrowband perfect absorptions at the resonance wavelengths of , , and , which perfectly match the atmospheric absorption bands while maintaining relatively low emissivity in the atmospheric transparency windows of and . Later, the functionality of design I is extended, which is called design II, to include a broadband absorption at the near-infrared region to minimize the solar irradiation reflection from the nanoantenna emitter. Finally, single- and three-layer graphene are introduced to provide a real-time tuning of the infrared signature of the proposed nanoantenna emitter (design II). It is also demonstrated that the three-layer graphene structure can suppress an undesired absorption resonance wavelength related to the intrinsic vibrational modes (optical phonons) of the SiO2 layer by compared to for the single-layer one. The spectral analysis of design I is validated using both analytical and numerical approaches where the numerical simulation domain is extended for the analysis of design II. The thermal characteristic analyses of design I and design II (without/with graphene layers) reveal that infrared signatures of the blackbody radiation are significantly reduced for the whole wavelength spectrum at least by and within a wide temperature ranging from room temperature to , respectively.

AT2ES: Simultaneous Atmospheric Transmittance-Temperature-Emissivity Separation Using Online Upper Midwave Infrared Hyperspectral Images

This paper presents a novel method for atmospheric transmittance-temperature-emissivity separation (AT2ES) using online midwave infrared hyperspectral images. Conventionally, temperature and emissivity separation (TES) is a well-known problem in the remote sensing domain. However, previous approaches use the atmospheric correction process before TES using MODTRAN in the long wave infrared band. Simultaneous online atmospheric transmittance-temperature-emissivity separation starts with approximation of the radiative transfer equation in the upper midwave infrared band. The highest atmospheric band is used to estimate surface temperature, assuming high emissive materials. The lowest atmospheric band (CO2 absorption band) is used to estimate air temperature. Through onsite hyperspectral data regression, atmospheric transmittance is obtained from the y-intercept, and emissivity is separated using the observed radiance, the separated object temperature, the air temperature, and atmospheric transmittance. The advantage with the proposed method is from being the first attempt at simultaneous AT2ES and online separation without any prior knowledge and pre-processing. Midwave Fourier transform infrared (FTIR)-based outdoor experimental results validate the feasibility of the proposed AT2ES method.

Improving cabin thermal environment of parked vehicles under direct sunlight using a daytime radiative cooling cover

Car overheating after parking under the direct sunshine leads to not only more energy consumption of air conditions but also potential security issues, such as higher traffic accident rates and heatstroke of passengers. In this study, we propose a new type of car cover with the daytime radiative cooling effect (named as Cover R) to reduce interior temperature when parking outside. With utilizing a layer of innovative meta-material coating, this cover is capable of reflecting most sunlight and effectively emitting infrared radiation in the atmospheric window band (8–13 μm). Experimental results have shown that under strong solar irradiation (>900 W/m2), the usage of Cover R decreases cabin air temperature by 31.1 °C and 19.6 °C compared that for a car without a cover and with a traditional cover, respectively, which efficiently avoids thermal shock to the passengers. A simulation model that reproduces experimental data well suggests that Cover R is able to improve personal comfort in hot days. Considering the initial energy cost of air conditions for high interior temperatures, the application of Cover R also saves gasoline and reduces carbon dioxide emission.

Speed-dependent broadening of the [formula omitted] fine-structure lines

Pressure broadening of the molecular oxygen fine-structure lines near 60 GHz was experimentally reexamined in the range of rotational quantum numbers up to N=39, in the pure gas at room temperature. The analysis of a representative set of individual line profiles with N varying from 1 to 21 included the speed dependence of collisional relaxation, which affects absorption by 0.25–0.5% of maximum at low pressures. The ratio of the two speed-dependence parameters γ0 and γ2 exhibits no notable variation with N. Obtained data are compared with similar parameters of other oxygen bands in the near-infrared and visible spectral ranges. Assuming similar speed dependence in air as for pure oxygen, we find that at 1-atm pressure, the impact of introducing speed-dependent line mixing and broadening coefficients into a model for the atmospheric oxygen 60-GHz band is 0.05–0.1% of maximum absorption, much smaller than the influence of either first- or second-order speed-independent line mixing.

Tuning of mid-infrared absorption through phonon-plasmon-polariton hybridization in a graphene/hBN/graphene nanodisk array.

In this paper, we utilize a heterostructured graphene/hBN/graphene nanodisk array to implement an electrically tunable absorber in and out of the Reststrahlen band (RSB) region of hBN. Tuning of phonon-type resonance absorption in the RSB region is achieved through phonon-plasmon-polariton hybridization. The hybrid phonon mode enabled a 290 nm shift of the resonant wavelength, and the sensitivity of absorption peak to the electrical control is 362.5 nm/eV. Simultaneously, the nearly perfect absorption is obtained in the condition of high chemical potential of graphene. Moreover, the plasmon polaritons are strongly modified by phonon polaritons of hBN, so the FWHM of absorption peaks out of the RSB region reduce to 45-49 nm, and the maximum Q of absorption reaches 220.44 at EF=0.65 eV, which is paving a way toward coherent emission at the atmospheric transparent band. Importantly, graphene-assisted hyperbolic phonon polaritons of hBN will enable future phonon devices with high optical performance and wide tunability.

Nighttime O(1D) and corresponding Atmospheric Band emission (762 nm) derived from rocket-borne experiment

Based on common volume rocket-borne measurements of temperature, densities of atomic oxygen and neutral air, we derived O(1D) nighttime concentrations and corresponding Atmospheric band emission (762 nm). This is one of the first retrievals of the nighttime O(1D) concentration. Recently, Kalogerakis, Sharma and co-workers have suggested a new production path of O(1D) based on the reaction of vibrationally excited OH and O. We calculate Atmospheric band volume emission related to the population of O2(b1Σg+) from O(1D) and compare with total Atmospheric band emissions observed during the same rocket launch. This allows an estimation of the relative contribution of the new Kalogerakis-Sharma mechanism (KSM) to the total Atmospheric band emission. The concentration of O(1D) due to KSM amounts to several tens cm−3 with a peak around 95 km. The KSM gives an essential contribution to the total Atmospheric band volume emission (762 nm). Additionally, we illustrate analytically that the expressions for volume emission by the new KSM and the traditional two-step mechanism have similar functional dependences on the atmospheric concentrations of O and O2. This causes an ambiguity, when interpreting Atmospheric band observations in terms of the one mechanism or the other.

On how atmospheric temperature affects the intensity of oxygen emissions in the framework of the Barth’s mechanism

The three-body recombination of oxygen atoms O + O + M → O2(el) + M is the dominant process of oxygen excitation in the Earth’s nightglow at altitudes of 85–110 km. The rate coefficient of this reaction, as well as the quantum yields of electronically excited products (O2(el) in the electronic states: 5πg, A3Σu+, A′3Δu, c1Σu+, b1Σg+, a1Δg, X3Σg-) depend on the gas kinetic temperature. In addition to the direct one-stage excitation channel of these levels of the O2 molecule, the Barth’s mechanism considers the two-stage energy transfer channel. In this channel, higher excited levels of the O2 act as precursors for the excitation of the O(1S) atom and the underlying electronic levels of the O2. In this study, we use sensitivity analysis to consider the temperature dependence of the processes of excitation and quenching for each of the excited components. The analytical expressions are obtained for the sensitivity coefficients of the Volume Emission Rates depending on temperature for the green line of atomic oxygen O(1S → 1D), the Herzberg I band O2(A3Σu+→X3Σg-) and O2 Atmospheric band O2(b1Σg+,v'=0→X3Σg-, v''=0). With the help of the sensitivity analysis performed in this work, we (a) confirm that the state O2(5πg), produced by the three-body recombination of atomic oxygen, is a precursor for the formation of O2(b1Σg+), (b) estimate the quantum yield of the O2(b1Σg+) state formed as a result of collisional reaction O2(5πg) with O2, and (c) propose a method for determining a type of precursor for production of O(1S) in the Barth's mechanism.

Retrieval of daytime mesospheric ozone using OSIRIS observations of O<sub>2</sub> (<i>a</i><sup>1</sup>Δ<sub>g</sub>) emission

Abstract. Improving knowledge of the ozone global distributions in the mesosphere–lower thermosphere (MLT) is a crucial step in understanding the behaviour of the middle atmosphere. However, the concentration of ozone under sunlit conditions in the MLT is often so low that its measurement requires instruments with very high sensitivity. Fortunately, the bright oxygen airglow can serve as a proxy to retrieve the daytime ozone density indirectly, due to the strong connection to ozone photolysis in the Hartley band. The OSIRIS IR imager (hereafter, IRI), one of the instruments on the Odin satellite, routinely measures the oxygen infrared atmospheric band (IRA band) at 1.27 µm. In this paper, we will primarily focus on the detailed description of the steps done for retrieving the calibrated IRA band limb radiance (with <10 % random error), the volume emission rate of O2 (a1Δg) (with <25 % random error) and finally the ozone number density (with <20 % random error). This retrieval technique is applied to a 1-year sample from the IRI dataset. The resulting product is a new ozone dataset with very tight along-track sampling distance (<20 km). The feasibility of the retrieval technique is demonstrated by a comparison of coincident ozone measurements from other instruments aboard the same spacecraft, as well as zonal mean and monthly average comparisons between Odin-OSIRIS (both spectrograph and IRI), Odin-SMR and Envisat-MIPAS. We find that IRI appears to have a positive bias of up to 25 % below 75 km, and up to 50 % in some regions above. We attribute these differences to uncertainty in the IRI calibration as well as uncertainties in the photochemical constants. However, the IRI ozone dataset is consistent with the compared dataset in terms of the overall atmospheric distribution of ozone between 50 and 100 km. If the origin of the bias can be identified before processing the entire dataset, this will be corrected and noted in the dataset description. The retrieval technique described in this paper can be further applied to all the measurements made throughout the 19 year mission, leading to a new, long-term high-resolution ozone dataset in the middle atmosphere.

Temperature-Dependent Emissivity Models of Aeronautical Alloy DD6 and Modified Function for Emissivity Computation with Different Roughness

In this study, the spectral emissivity of aeronautical alloy DD6 at eight temperatures (473 K, 523 K, 573 K, 623 K, 673 K, 723 K, 773 K and 823 K) over the spectral range from 3 μm to 20 μm is systematically studied under argon condition. The multi-temperature calibration method is adopted to accurately obtain the FTIR spectrometer response, and then the improved method that eliminates the disturbances caused by background radiation is used for spectral emissivity determination. The effects of temperature, wavelength and surface roughness on the spectral emissivity of DD6 are investigated. The results show that the spectral emissivity increases with increasing temperature and decreases with increasing wavelength, and the emissivity increases with increasing surface roughness. The fitting relationship between the spectral emissivity and temperature is established, and it is found that the fitting results of the complex model are more consistent than those of other models. To verify the validity of the complex model, the temperature inferred from the model is compared with that measured by the radiometer and thermocouple directly. The modified emissivity model based on the Agababov roughness function is established to infer the spectral emissivity of samples with different surface roughness. The relative combined uncertainty of spectral emissivity is evaluated to be better than 3.2% except for the atmospheric absorption bands.

The surprisingly carbon-rich environment of the S-type star W Aql,

Context. W Aql is an asymptotic giant branch (AGB) star with an atmospheric elemental abundance ratio C/O ≈ 0.98. It has previously been reported to have circumstellar molecular abundances intermediate between those of M-type and C-type AGB stars, which respectively have C/O < 1 and C/O > 1. This intermediate status is considered typical for S-type stars, although our understanding of the chemical content of their circumstellar envelopes is currently rather limited. Aims. We aim to assess the reported intermediate status of W Aql by analysing the line emission of molecules that have never before been observed towards this star. Methods. We performed observations in the frequency range 159−268 GHz with the SEPIA/B5 and PI230 instruments on the APEX telescope. We made abundance estimates through direct comparison to available spectra towards a number of well-studied AGB stars and based on rotational diagram analysis in the case of one molecule. Results. From a compilation of our abundance estimates and those found in the literature for two M-type (R Dor, IK Tau), two S-type (χ Cyg, W Aql), and two C-type stars (V Aql, IRC +10 216), we conclude that the circumstellar environment of W Aql appears considerably closer to that of a C-type AGB star than to that of an M-type AGB star. In particular, we detect emission from C2H, SiC2, SiN, and HC3N, molecules previously only detected towards the circumstellar environment of C-type stars. This conclusion, based on the chemistry of the gaseous component of the circumstellar environment, is further supported by reports in the literature on the presence of atmospheric molecular bands and spectral features of dust species which are typical for C-type AGB stars. Although our observations mainly trace species in the outer regions of the circumstellar environment, our conclusion matches closely that based on recent chemical equilibrium models for the inner wind of S-type stars: the atmospheric and circumstellar chemistry of S-type stars likely resembles that of C-type AGB stars much more closely than that of M-type AGB stars. Conclusions. Further observational investigation of the gaseous circumstellar chemistry of S-type stars is required to characterise its dependence on the atmospheric C/O. Non-equilibrium chemical models of the circumstellar environment of AGB stars need to address the particular class of S-type stars and the chemical variety that is induced by the range in atmospheric C/O.

Multiband metamaterial selective absorber for infrared stealth.

Nanostructured selective absorbers have widespread applications ranging from artificial color to thermophotovoltaics and radiative cooling. In this paper, we propose a metamaterial selective absorber with a metal-insulator-metal structure for infrared stealth. It can realize multiband absorption, and one sharp peak is at 1.54 µm, which can be used to reduce the scattering signals in laser-guided missiles. The other two relatively broad absorption peaks are at 2.83 µm and 6.11 µm, which can match the atmospheric absorption band. It can reduce up to 90 % of the detected infrared signals while maintaining a relatively high level of thermal emission capability. The dependence of the spectral characteristics on the incident angle is studied. The infrared signatures of the structure could be suppressed across a wide temperature range.

Surface Chlorophyll Enhancement in Mesoscale Eddies by Submesoscale Spiral Bands

AbstractOceanic submesoscale processes (with scales ~1–10 km and approximately days) have been progressively recognized as an important upwelling mechanism to close the upper ocean nutrient budget and sustain the primary production in euphotic layer. Spiral band is one of the most typical submesoscale structures of mesoscale eddies, characterized with enhancement of surface chlorophyll concentration. By combining satellite ocean‐color, satellite‐altimetry, and surface drifter data, we find that the oceanic spiral chlorophyll bands emerge globally and share a series of structural and kinematic features with atmospheric spiral rain bands of tropical cyclones, which indicate that they are footprints of the vertical motions induced by vortex Rossby waves embedded in eddies. As vortex Rossby waves are closely related to eddy evolution under background deformation, further observational analysis indicates that an intense eddy energy variation and a strong background deformation field constitute the favorable conditions for the emergence of the spiral chlorophyll bands.

Coupled heat transfer analysis and experiments to evaluate the radiative cooling potential of concrete and green roofs for buildings

Improving building energy efficiency is one of the most important challenges towards the mitigation of climate change concerns. Buildings use significant amount of energy for cooling loads. Development of new night-time and day-time radiative cooling modalities by roofs is essential for reducing the energy consumption during the summer months. If a surface is desired to be kept cool while exposed to the sun, it should have (i) the maximum reflection of solar energy at visible wavelength range, and (ii) the maximum radiative emission from the surface at atmospheric radiation bands (8–13 μm wavelength range). In this study, reinforced concrete panels and three different types of plant-covered roof layers were investigated for their potential use for passive cooling applications, including moss, cactus and green leaves. Fourier transform infrared spectroscopy (FTIR) measurements were conducted to determine the absorbance of different samples at infrared wavelengths. In addition, reverse heat leak method was used to determine the effective conductivity values (R-values). The power of cooling parameter of each sample was determined first, and after that a coupled radiation and conduction heat transfer analysis was carried out to evaluate their insulation potential. It was demonstrated that moss is a better candidate to be used as a radiative cooling material, and it is a better insulator than the other tested materials.

Gravity wave activity in the middle atmosphere from SATI airglow observations at northern mid-latitude: Seasonal variation and comparison with tidal and planetary wave-like activity

The study investigates the gravity waves activity detected in the mesosphere/lower thermosphere (MLT) region (80–120 km) using airglow observations performed by the Spectral Airglow Temperature Imager (SATI) at the Sierra Nevada Observatory (SNO) (37.06∘N, 3.38∘W). In this analysis column emission rates of the OH Meinel (6–2) and O2 Atmospheric (0–1) bands, as well as rotational temperatures derived from these emission rates are employed for the period of 1998–2015. The long time series allows the determination of gravity waves climatology at this site. The gravity wave activity content exhibits an annual variability with a maximum during winter and a faint increase in summer. It was found that gravity waves with periods of less than 3h are more prevalent than those with periods of 3–6h throughout the year, for both column emission rates and rotational temperatures. The gravity wave activity with periods of less than 3h is larger in summer, while gravity waves with period from 3 to 6 h have maximum activity around autumn-winter. The analysis showed that the gravity waves activity surpassed that of the semidiurnal tides, although was still smaller than the planetary wave activity, especially in summer when the planetary waves appear to dominate the dynamics of the MLT region. In general, wave activity is the main source of variability in both OH and O2 airglow emissions with the planetary wave activity being the main driver of the O2 emission variability. However, the rotational temperatures are more affected by seasonal variations, especially the OH rotational temperatures, accounting for more than the 40% of the overall observed variability.

Trends in the Airglow Temperatures in the MLT Region—Part 1: Model Simulations

Airglow intensity-weighted temperature variations induced by the CO2 increase, solar cycle variation (F10.7 as a proxy) and geomagnetic activity (Ap index as a proxy) in the Mesosphere and Lower Thermosphere (MLT) region were simulated to quantitatively assess their influences on airglow temperatures. Two airglow models, MACD-00 and OHCD-00, were used to simulate the O(1S) greenline, O2(0,1) atmospheric band, and OH(8,3) airglow temperature variations induced by these influences to deduce the trends. Our results show that all three airglow temperatures display a linear trend of ~−0.5 K/decade, in response to the increase of CO2 gas concentration. The airglow temperatures were found to be highly correlated with Ap index, and moderately correlated with F10.7, with the OH temperature showing an anti-correlation. The F10.7 and Ap index trends were found to be ~−0.7 ± 0.28 K/100SFU and ~−0.1 ± 0.02 K/nT in the OH temperature, 4.1 ± 0.7 K/100SFU and ~0.6 ± 0.03 K/nT in the O2 temperature and ~2.0 ± 0.6 K/100SFU and ~0.4 ± 0.03 K/nT in the O1S temperature. These results indicate that geomagnetic activity can have a rather significant effect on the temperatures that had not been looked at previously.

Bulk material based selective infrared emitter for sub-ambient daytime radiative cooling

Through passively emitting excess heat to the outer space, radiative cooling has been demonstrated as an efficient way for energy saving applications. Instead of well-designed photonic structures, we rediscovered the potential of a bulk material as a selective emitter for sub-ambient daytime radiative cooling. The proposed cooler, consisting of a 1-mm-thick lithium fluoride crystal coated with silver backing, exhibits a low solar absorptance of 4.7% and nearly ideal infrared selectivity with high emission exactly within the atmospheric transmission band (i.e., 8–13 μm). Potentially, the cooler could achieve an ultra-low stagnation temperature up to 57 °C below the ambient. Sub-ambient daytime cooling performance was also demonstrated in an outdoor test with cooler stagnation temperature below the ambient one by 5 °C under solar irradiance above 900 W/m2 and a net cooling power of about 60 W/m2 in thermal equilibrium with the ambient. The proposed simple selective infrared emitter could efficiently and passively cool optical systems due to the wide applications of lithium fluoride crystal as optical windows and mirrors.

Effect of OH emission on the temperature and wind measurements derived from limb-viewing observations of the 1.27 µm O2 dayglow

Abstract. The O2(a1Δg) emission near 1.27 µm is well-suited for remote sensing of global wind and temperature in near-space by limb-viewing observations to its bright signal and extended altitude coverage. However, vibrational–rotational emission lines of the OH dayglow produced by the hydrogen–ozone reaction (H+O3→OH•+O2) overlap the infrared atmospheric band emission (a1Δg→X3Σg) of O2. The main goal of this paper is to discuss the effect of OH emission on the wind and temperature measurements derived from the 1.27 µm O2 dayglow limb-viewing observations. The O2 dayglow and OH dayglow spectrum over the spectral region and altitude range of interest is calculated by using the line-by-line radiative transfer model and the most recent photochemical model. The method of four-point sampling of the interferogram and sample results of measurement simulations are provided for both O2 dayglow and OH dayglow. It is apparent from the simulations that the presence of OH dayglow as an interfering species decreases the wind and temperature accuracy at all altitudes, but this effect can be reduced considerably by improving OH dayglow knowledge.

Evaluation of Remote Sensing Reflectance Derived From the Sentinel-2 Multispectral Instrument Observations Using POLYMER Atmospheric Correction

With a five-day revisit frequency over coastal regions and a spatial resolution of 10–60 m, the Sentinel-2 multispectral instrument (MSI) has shown its capacity to provide a reasonably accurate remote sensing reflectance ( $R_{\mathrm {rs}}$ ) data product over water when the standard “black pixel” (BP) atmospheric correction algorithm was applied to the top-of-atmospheric (TOA) reflectance data. Alternative atmospheric correction approaches, such as the POLYnomial-based algorithm applied to Medium Resolution Imaging Spectrometer (MERIS) (POLYMER), may show advantages under nonoptimal observation conditions (e.g., in the presence of strong sun glint). Here, POLYMER is implemented to process the data collected by both MSI and the Moderate Resolution Imaging Spectroradiometer (MODIS) with the resulting $R_{\mathrm {rs}}$ evaluated with concurrent and colocated in situ $R_{\mathrm {rs}}$ data collected from the AERONET-OC platforms. The results indicate less uncertainties in the MSI $R_{\mathrm {rs}}$ than those in the MODIS $R_{\mathrm {rs}}$ , and also less uncertainties in the MSI $R_{\mathrm {rs}}$ than those reported earlier. This is possibly attributed to the spatial heterogeneity of coastal waters where MODIS coarse-resolution data may suffer, and to the high-quality AERONET-OC data. In addition, for the evaluation data set, MSI $R_{\mathrm {rs}}$ does not appear to suffer from adjacency effects from the AERONET-OC platform and clouds, leading to more coverage than MODIS in nearshore waters. However, MSI $R_{\mathrm {rs}}$ is noisy in relatively clear waters, possibly due to the noisy TOA reflectance in the atmospheric correction bands over clear waters.

The MATS satellite mission – gravity wave studies by Mesospheric Airglow/Aerosol Tomography and Spectroscopy

Abstract. Global three-dimensional data are a key to understanding gravity waves in the mesosphere and lower thermosphere. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that addresses this need. It applies space-borne limb imaging in combination with tomographic and spectroscopic analysis to obtain gravity wave data on relevant spatial scales. Primary measurement targets are O2 atmospheric band dayglow and nightglow in the near infrared, and sunlight scattered from noctilucent clouds in the ultraviolet. While tomography provides horizontally and vertically resolved data, spectroscopy allows analysis in terms of mesospheric temperature, composition, and cloud properties. Based on these dynamical tracers, MATS will produce a climatology on wave spectra during a 2-year mission. Major scientific objectives include a characterization of gravity waves and their interaction with larger-scale waves and mean flow in the mesosphere and lower thermosphere, as well as their relationship to dynamical conditions in the lower and upper atmosphere. MATS is currently being prepared to be ready for a launch in 2020. This paper provides an overview of scientific goals, measurement concepts, instruments, and analysis ideas.

Wavelength Calibration Correction Technique for Improved Emissivity Retrieval

Accurate retrieval of surface emissivity from long-wave infrared hyperspectral imaging data is necessary for many scientific and defense applications. Emissivity retrieval requires an atmospheric model for the scene and consists of two interwoven steps: atmospheric compensation (AC) and temperature–emissivity separation (TES). AC converts the at-aperture radiance to ground radiance, and TES uses the ground radiance to produce a temperature and emissivity estimate. TES assumes that emissivity spectra for solids are smooth, compared to atmospheric features. Model-based techniques find an atmospheric model, which produces the smoothest emissivity estimates. The high-resolution model must be band averaged to the sensor's spectral response function (SRF), which is difficult to characterize and maintain. Any errors in the SRF cause errors in the atmospheric spectra and roughness in the emissivity estimates. We propose a technique that improves the quality of the retrieved emissivity by correcting band-averaging errors of the model from the SRF. An in-scene AC (ISAC) technique is used to find pixels containing a high emissivity material. Atmospheric model bands far from absorption features and a material library are then used to identify the material and estimate the pixel temperatures. At-aperture radiance spectra are generated for the pixels, instead of the ground radiance spectra generated by ISAC. The linear relationship between the generated and measured at-aperture radiances is used to determine model correction factors. Using simulated data, we demonstrate the capability of this technique to substantially reduce calibration error effects in the corrected atmospheric spectra and retrieved emissivities.