Long-wave Band Research Articles

Impact of Assimilating Geostationary Interferometric Infrared Sounder Observations from Long- and Middle-Wave Bands on Weather Forecasts with a Locally Cloud-Resolving Global Model

The Geostationary Interferometric InfraRed Sounder (GIIRS) provides a novel opportunity to acquire high-spatiotemporal-resolution atmospheric information. Previous studies have demonstrated the positive impacts of assimilating GIIRS radiances from either long-wave temperature or middle-wave water vapor bands on modeling high-impact weather processes. However, the impact of assimilating both bands on forecast skill has been less investigated, primarily due to the non-identical geolocations for both bands. In this study, a locally cloud-resolving global model is utilized to assess the impact of assimilating GIIRS observations from both long-wave and middle-wave bands. The findings indicate that the GIIRS observations exhibit distinct inter-channel error correlations. Proper inflation of these errors can compensate for inaccuracies arising from the treatment of the geolocation of the two bands, leading to a significant enhancement in the usage of GIIRS observations from both bands. The assimilation of GIIRS observations not only markedly reduces the normalized departure standard deviations for most channels of independent instruments, but also improves the atmospheric states, especially for temperature forecasting, with a maximum reduction of 42% in the root-mean-square error in the lower troposphere. These improvements contribute to better performance in predicting heavy rainfall.

Updating the radiation infrastructure in MESSy (based on MESSy version 2.55)

Abstract. The calculation of the radiative transfer is a key component of global circulation models. In this article, we describe the most recent updates of the radiation infrastructure in the Modular Earth Submodel System (MESSy). These updates include the implementation of the PSrad radiation scheme within the RAD submodel. Furthermore, the radiation-related submodels CLOUDOPT (for the calculation of cloud optical properties) and AEROPT (for the calculation of aerosol optical properties) have been updated and are now more flexible in order to deal with different sets of shortwave and longwave bands of radiation schemes. In the wake of these updates, a new submodel (ALBEDO), which features solar-zenith-angle-dependent albedos and a new satellite-based background (white sky) albedo, was created. All of these developments are backward compatible, and previous features of the MESSy radiation infrastructure remain available. Moreover, these developments mark an important step in the use of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model, as the update of the radiation scheme was a key aspect in the development of the sixth generation of the European Centre for Medium-Range Weather Forecasts – HAMburg (ECHAM6) model from ECHAM5. The developments presented here are also aimed towards using the MESSy infrastructure with the ICOsahedral Non-hydrostatic (ICON) model as a base model. The improved infrastructure will also aid in the implementation of additional radiation schemes once this should be needed. We have optimized the set of free parameters for two general circulation model-type (GCM-type) setups for pre-industrial and present-day conditions: one with the radiation scheme that was used to date (i.e. the radiation scheme of ECHAM5) and one with the newly implemented PSrad radiation scheme. After this parameter optimization, we performed four model simulations and evaluated the corresponding model results using reanalysis and observational data. The most apparent improvements related to the updated radiation scheme are the reduced cold biases in the tropical upper troposphere and lower stratosphere and the extratropical lower stratosphere and a strengthened polar vortex. The former is also related to improved stratospheric humidity and its variability if the new radiation scheme is employed. Using the multiple radiation call capability of MESSy, we have applied the two model configurations to calculate instantaneous and stratospheric-adjusted radiative forcings related to changes in greenhouse gases. Overall, we find that for many forcing experiments the simulations with the new radiation scheme show improved radiative forcing values. This is in particular the case for methane radiative forcings, which are considerably higher when assessed with the new radiation scheme and thus in better agreement with reference values.

GeAsSeTe/GeAsSe Pedestal Waveguides for Long-Wave Infrared Tunable on-Chip Spectroscopy

A dry-etched pedestal chalcogenide waveguide platform, designed for use in long-wave IR spectrometer applications, is demonstrated, fabricated and optically characterized. The optical layers were deposited on pre-patterned dry-etched silicon pedestals. An exceptionally low waveguide propagation loss was measured, at around 0.1 dB/cm at λ = 10 μm. The modal thermo-optic coefficient of the waveguide was experimentally estimated to be approximately 1.1 × 10−4 C−1 at λ = 1.63 μm, which is comparable to that of Si and GaAs. Waveguide spiral interferometers were fabricated, proving the potential for realization of more complex, chalcogenide-based, integrated photonic circuits. The combination of low propagation losses and a strong thermo-optic coefficient makes this platform an ideal candidate for utilization in on-chip tunable spectrometers in the long-wave IR wavelength band.

A COMPARATIVE STUDY OF THE COMPONENT COMPOSITION OF THE HERBS OF SOME SPECIES OF THE GENUS ACHILLEA L.

The article presents the results of a comparative study of the component composition of herbs of some species of the genus Achillea L. growing in the Samara region - common yarrow (Achillea millefolium L.), cartilaginous yarrow (Achillea cartilaginea (Ledeb. ex Rchb.) and noble yarrow (Achillea nobilis (L.). Spectrophotometry and high performance liquid chromatography were used as methods of investigation.
 As a result of comparative spectrophotometric analysis of water-alcoholic extracts of common yarrow herbs, yarrow cartilaginous herbs and noble yarrow herbs revealed that the absorption curve of their UV spectra is due mainly to hydroxycinnamic alcohols, in particular chlorogenic and caffeic acids (290 sh. and 330 nm). When aluminum (III) chloride solution was added to the water-alcoholic extracts of yarrow herb from the studied species, a bathochromic shift of the long-wave band at 400 nm was observed due to the flavonoids.
 The content of total flavonoids in the plant raw material is: common yarrow - 0.68±0.01%, cartilaginous yarrow - 0.65±0.02%, noble yarrow - 0.69±0.02%.
 Chlorogenic acid, cynaroside, cosmosiin, apigenin and luteolin were identified in water-alcoholic extracts from the above described species using HPLC method. In addition, the presence of caffeic acid was detected in the water-alcoholic extracts of noble yarrow herbs.
 The content of cosmosiin in the plant raw material is: common yarrow - 0.61±0.01%, cartilaginous yarrow - 0.56±0.02%, noble yarrow - 0.62±0.02%.
 The results of the study can be used in the development of regulatory documentation for medicinal plant material "Yarrow herb" for inclusion in the State Pharmacopoeia of the Russian Federation.

Fluorescent Sensor Based on 1H-Pyrazolo[3,4-b]quinoline Derivative for Detecting Zn2+ Cations.

The photophysical and sensory properties of the donor-acceptor pyrazoloquinoline derivative (PQPc) were investigated using absorption, steady-state, and time-resolved fluorescence measurements. The compound synthesized from commercial, readily available substrates exhibited absorptions in the UV-Vis range, with a maximum of the longwave band around 390 nm. The maximum fluorescence was around 460-480 nm, depending on the solvent. The quantum yield was between 12.87% (for n-hexane) and 0.75% (for acetonitrile) and decreased with increasing solvent polarity. The PET mechanism was implicated as the cause of fluorescence quenching. Divalent ions such as Zn2+, Pb2+, Cd2+, Ca2+, Mg2+, Co2+, Ni2+, and Cu2+ were introduced to study the fluorescent response of PQPc. A 13-times increase in fluorescence quantum yield was observed after the addition of Zn2+ ions. Detailed research was carried out for the PQPc-Zn2+ system in order to check the possibility of analytical applications of PQPc as a fluorescent sensor. A detection limit of Zn2+ was set at the value level 1.93 × 10-7 M. PQPc-Zn2+ complexes had a stoichiometry of 1:1 with a binding constant of 859 M-1. Biological studies showed that the sensor was localized in cells near the membrane and cytoplasm and may be used to detect zinc ions in eukaryotic cells.

Design of narrowband infrared emitters by hybridizing guided-mode resonance structures with van der Waals materials

In this paper, narrowband emitters have been designed using particle swarm optimization (PSO) in the 10–20 μm infrared range. The device structure consists of an anisotropic α-MoO3 layer combined with the one- and two-dimensional guided-mode resonance structures. Well-defined absorption lines are present in the reflection spectrum for both TE and TM polarizations, thereby yielding narrowband emissivity at desired wavelengths. The band structure of the designed emitters under TM polarization demonstrates distinct features unlike its TE counterpart. These features are attributed to the interaction between guided-mode resonances and phonon polaritons. The results are relevant for applications in active and passive photonic elements in mid- and long-wave IR bands.

Characteristics of Air Pollutant Distribution and Sources in the East China Sea and the Yellow Sea in Spring Based on Multiple Observation Methods

The composition of marine aerosol is quite complex, and its sources are diverse. Across the East China Sea (ECS) and the Yellow Sea (YS), multi-dimensional analysis of marine aerosols was conducted. The characteristics of carbonaceous aerosols and gaseous pollutants were explored through in situ ship-based observation, MERRA-2 reanalysis datasets and TROPOMI data from Sentinel-5P satellite. Black carbon (BC)’s average concentration is 1.35 ± 0.78 μg/m3, with high-value BC observed during the cruise. Through HYSPLIT trajectory analysis, sources of BC were from the northern Eurasian continent, the Shandong Peninsula, the ECS and Northwest Pacific Ocean (NWPO). The transport of marine sources like ship emissions cannot be ignored. According to the absorption Angstrom exponent (AAE), BC originates from biomass burning (BB) in the shortwave band (~370 nm) and from fossil fuel combustion in the longwave band (~660 nm). Organic carbon (OC), sulfate (SO42−) and BC report higher Angstrom exponent (AE) while dust and sea salt reveal lower AE, which can be utilized to classify the aerosols as being fine- or coarse-mode, respectively. OC has the highest AE (ECS: 1.98, YS: 2.01), indicating that anthropogenic activities could be a significant source. The process of biomass burning aerosol (BBA) mixed with sea salt could contribute to the decline in BBA’s AE. Ship emissions may affect the distribution of tropospheric nitrogen dioxide (NO2) in the ECS, especially during the COVID-19 pandemic. Tropospheric NO2 over the YS has the highest value (up to 12 × 1015 molec/cm2). Stratospheric NO2 has a ladder-like distribution from north to south, and the variation gradient was lower than that in the troposphere. Carbon monoxide (CO) accumulates in the south and east of the ECS and the east of the YS, while the variation over the eastern YS is relatively frequent. Seas near the Korean Peninsula have extremely high CO concentration (up to 1.35 × 1017 molec/cm2).

Trap state and exciton luminescence of colloidal PbS quantum dots coated with thioglycolic acid molecules

This work presents the results of studying the IR luminescence of colloid PbS quantum dots coated with molecules of thioglycolic acid. Luminescence of the sample was recorded using the InGaAs image sensor PDF 10C/M (ThorlabsInc., USA) and a diffraction monochromator with 600 mm-1 grating. To study the temperature dependence of luminescence, the sample was cooled in a nitrogen cryostat down to 80 К. A redistribution of the luminescence intensity between two peaks (1100 and 1280 nm) was identified upon a decrease in temperature. It was shown that an exciton absorption peak was present in the excitationspectrum for the short-wave luminescence peak, and the Stokes shift was ΔEstokes ~ 0.1 eV. On the contrary, the exciton peak was absent in the luminescence excitation spectrum of the long-wave band, and its red boundary was shifted towards the short-wave region, that provided the Stokes shift of more than 0.3 eV. It was concluded that the short-wave luminescence band appeared as a result of the radiative annihilation of an exciton, while the long-wave band appeared due to the recombination of charge carriers at trap states. Trap state luminescence was effectively excited upon direct absorption of the radiation by the luminescence centre. A three-level diagram was suggested that determined the IR luminescence of colloid PbS quantum dots coated with thioglycolic acid molecules.

Optical and Sensing Properties of Carbon Colloidal Particles Based on (Thio)urea and Citric Acid: Effect of the Components Ratio

Changing the composition of a precursors mixture is a powerful tool to tune the structure and properties of carbonaceous nanoparticles synthesized via the solvothermal route. We have addressed the influence of the ratio of urea or thiourea to citric acid during their solvothermal treatment in dimethylformamide on the optical and sensing properties of the obtained colloidal product. It has been found that the urea-derived products are more diverse in comparison with the thiourea-based ones. The excitation-dependent fluorescence of the products and their sensitivity to mercury(II) ions have been investigated; one to three types of fluorophores have been observed in the products depending on the composition. The nanoparticles prepared in excess of urea have been found more sensitive to the heavy metal, with the sensitivity of the long-wave emission band being superior.

Evaluating the Value of CrIS Shortwave-Infrared Channels in Atmospheric-Sounding Retrievals

The Cross-track Infrared Sounder (CrIS), in low Earth orbit since 2011, makes measurements of the top of atmosphere radiance for input into data assimilation (DA) systems as well as the retrieval of geophysical state variables. CrIS measurements have 2211 narrow infrared channels ranging between 650 and 2550 cm−1 (~3.9–15.4 μm) and capture the variation in profiles of atmospheric temperature, water vapor, and numerous trace gas species. DA systems derive atmospheric temperature by assimilating CO2-sensitive channels in the CrIS longwave (LW) band (650–1095 cm−1). Here, we investigate if CO2-sensitive channels in the shortwave (SW) band (2155–2550 cm−1) can similarly be applied. We first evaluated the information content of the CrIS bands followed by an assessment of the performance degradation of retrievals due to the loss of individual CrIS bands. We found that temperature profile retrievals derived from the CrIS SW band were statistically both well-behaved and as accurate as a retrieval utilizing the CrIS LW band. The one caveat, however, is that the higher CrIS instrument noise in the SW band limited its performance under certain conditions. We conclude with a discussion on the implications our results have for channel selection in retrieval and DA systems as well as the design of future space instruments.

Extending laser wavelengths to 1630 nm in centimeter-scale Er-phosphate fiber.

The spectral bandwidth of Er-doped fibers limits their lasing wavelength at longer wave band. Here, to the best of our knowledge, we report a broad emission band (1420‒1680 nm) of Er3+ and demonstrate for the first time an Er-phosphate fiber, which supports laser oscillation at the extended wavelengths of 1627 nm and 1630 nm, with the output powers and slope efficiencies of 44 mW/12.5% and 16.5 mW/5.6%, respectively, pumped at 1480 nm. To the best of our knowledge, these are the highest output powers and slope efficiencies at 1627 nm and 1630 nm from an Er3+-doped all-fiber configuration.

Simulation of CrIS Radiances Accounting for Realistic Properties of the Instrument Responsivity That Result in Spectral Ringing Features

This paper provides a procedure for the simulation of radiances from the U. S. National Oceanic and Atmospheric Administration (NOAA) Cross-track Infrared Sounder (CrIS) Fourier Transform Spectrometer to include spectral ringing effects caused by the finite-band, non-flat instrument spectral response to incident radiation. A simulation using a line-by-line radiative transfer model is performed to illustrate the magnitude of the effect and to indicate which spectral channels are likely to be impacted. Comparisons with CrIS observations are made to show that for most channels this effect is negligibly small compared to errors in the radiative transfer calculations but for the longwave edge of the CrIS longwave band and a few other regions, the brightness temperature ringing is significant. While the ringing artifact described in this paper may appear to be removed when Hamming apodization is applied, as is done for the assimilation of CrIS data into Numerical Weather Prediction (NWP) models, it is still present, and its influence reappears if the spectral correlation induced by apodization is properly handled to preserve the information content that derives from high spectral resolution. Inclusion of the instrument responsivity in calculated spectra to properly mimic the observed spectra as defined here eliminates artifacts from this type of ringing. Users of CrIS radiances should consider whether this effect is important for their application.

High Performance Broadcast Receiver Based on Obsolete Technology.

Since its inception, the electronics industry has mass-produced equipment. The fast evolution of electronic technologies made obsolete the entire generation of products and even technologies. Until the government issued regulations and guidelines on how to address the issue of reuse of obsolete electronic equipment, with special regard to the ones still operating (e.g., give it to family/friends, donate to charity, or sell to individuals or recycling companies), most of it was thrown out with usual rubbish, with a destructive effect on the environment. This paper presents the design techniques and methods for revaluation of obsolete vacuum tube analog receivers, with a focus on the manufacturing steps of a high-performance receiver. The choice of receiver type is not accidental at all, since tube technology is still a real success among audiophiles many providers offer vacuum tube amplifiers at considerably high prices. The redesign implied the original FM unit replacement with a DSP-based AM/FM tuner while the AM RF vacuum tube section has been preserved with the original architecture to allow the reception of the broadcast stations for the long-wave band and the alternative operation with the silicon tuner for the medium-wave and short-wave bands. The electrical performances of the modified receiver in terms of reliability, sensitivity, selectivity, and distortions on the reception chain are clearly superior to the original one, while the power consumption of the RF section is reduced more than 10 times from 11.5 W–15.5 W to 1 W. Last, but not least important, the proposed solution implied the use of few additional parts and resources and extended significantly the lifetime of the original vacuum tubes receiver. The work has been developed to serve as an example of how obsolete electronic equipment can be redesigned and reused avoiding its complete recycling or even worse, its disposal with usual rubbish. It has been imagined and performed as the initial step in launching a professional student contest on the reuse/redesign of obsolete equipment aimed at raising awareness regarding the issue of pollution with e-waste amongst students from the electronic departments of Romanian technical universities.

Hybrid ray-tracing/Fourier optics method to analyze multilayer diffractive optical elements.

The performance (paraxial phase delay) of conventional diffractive optical elements is generally analyzed using the analytical scalar theory of diffraction, based on thin-element approximation (TEA). However, the high thickness of multilayer diffractive optical elements (MLDOEs) means that TEA yields inaccurate results. To address this, we tested a method based on ray-tracing simulations in mid-wave and long-wave infrared wave bands and for multiple f-numbers, together with the effect of MLDOE phase delay on a collimated on-axis beam with an angular spectrum method. Thus, we accurately generate optical figures of merit (point spread function along the optical axis, Strehl ratio at the "best" focal plane, and chromatic focal shift) and, by using a finite-difference time-domain method as a reference solution, demonstrate it as a valuable tool to describe and quantify the longitudinal chromatic aberration of MLDOEs.

Parametric design and IR signature study of exhaust plume from elliptical-shaped exhaust nozzles of a low flying UAV using CFD approach

This paper describes the design, parametric study, and IR signature analysis of plume of a slit-shaped exhaust nozzle. Circular-shaped exhaust nozzles are generally used to get the essential thrust necessary for an aircraft flight. However, the Infrared (IR) signature of the exhaust plume emanating from these nozzles is very high, and the IR missile can easily lock and hit the aircraft. In this paper, the compressible flow CFD model using a realizable k-ε turbulence model is used to study the flow characteristics of the exhaust nozzle with different aspect ratios. The exit cross-section of the nozzle is kept elliptical up to a maximum aspect ratio of 10. IR signature for each nozzle shaped is calculated using a set of input parameters in Mid-wave IR and Long-wave IR spectral bands. The IR signature of exhaust plume in Long-wave IR spectral band is not significant due to high transmittance of species in the exhaust plume mixture. However, for this particular case of low flying UAV, a considerable reduction in the IR signature is recorded for the high aspect ratio nozzle in MWIR spectral band.

Effect of nitrate coatings on the optical properties of mineral dust particles during the haze aging process

The frequent occurrence of haze episodes in China poses a severe threat to human health. During the haze period, nitrate and mineral dust form a complex mixing state through heterogeneous reactions. The existing numerical models usually assume sulfate instead of nitrate in simulating the optical properties of aerosol, and the radiation difference between sulfate and nitrate needs to be evaluated. Therefore, it is significant to study the influence mechanism of nitrate coating on the optical properties of mineral particles during the haze aging process. In this study, the effects of nitrate coating on the scattering and polarization properties of mineral dust under multi-spectral conditions are investigated by core-shell spheroid models using the T-matrix method. The results show that the optical properties of mineral dust are wavelength dependent, whereas the coating ratio plays a governing role in the overall floating. The coating ratio changes with the haze aging process, which leads to a dramatic variation in the scattering and polarization properties at short wavelengths. For different coating ratios, the scattering phase function in the backward direction P11(π) can be approximately enhanced by a factor of 1.55, while the maximum value of P12(θ), P11(0) and the linear backscattering depolarization ratio are weakened by nearly 25%, 10%, 14% at 0.35µm, respectively. However, these effects are not obvious in the longer waveband. Overall, various coating structures are characterized by a reasonable number of limit tunable parameters, which is of great significance to understand the mixing structure and optical properties of mineral dust during the haze aging process.

Moving People Tracking and False Track Removing with Infrared Thermal Imaging by a Multirotor

Infrared (IR) thermal imaging can detect the warm temperature of the human body regardless of the light conditions, thus small drones equipped with the IR thermal camera can be utilized to recognize human activity for smart surveillance, road safety, and search and rescue missions. However, the unpredictable motion of the drone poses more challenges than a fixed camera. This paper addresses the detection and tracking of people through IR thermal video captured by a multirotor. For object detection, each frame is first registered with a reference frame to compensate for its coordinates. Then, the objects in each frame are segmented through k-means clustering and morphological operations. Falsely detected objects are removed considering the actual size and the shape of the object. The centroid of the segmented area is considered the measured position for target tracking. The track is initialized with two-point differencing initialization, and the target states are continuously estimated by the interacting multiple model (IMM) filter. The nearest neighbor association rule assigns the measurement to the track. Tracks that move slower than the minimum speed are terminated at the proposed criteria. In the experiments, three videos were captured with a long-wave IR band thermal imaging camera mounted on a multirotor. In the first and second videos, eight pedestrians on a pavement and three hikers on a mountain on winter nights were captured, respectively. In the third video, two walking people with complex backgrounds were captured on a windy summer day. The image characteristics vary between videos depending on the climate and surrounding objects, but the proposed scheme shows the robust performance in all cases; the average root mean squared errors in position and velocity are obtained as 0.08 m and 0.53 m/s, respectively for the first video, 0.06 m and 0.58 m/s, respectively for the second video, and 0.18 m and 1.84 m/s, respectively for the third video. The proposed method reduces false tracks from 10 to 1 in the third video.

Preliminary analysis of experimental cross-polarization images from polarimetric aircraft synthetic aperture radar of P-band

An analysis of polarimetric synthetic aperture radar (SAR) space observations usage for measuring Faraday rotation angle of plane-polarized electromagnetic radiation on the satellite-Earth-satellite route and calibrating the radar is performed. It is shown that technical characteristics of SAR, the radar movement during the survey and features of electromagnetic waves reflection from the rough Earth’s surface, as well as small-scale ionospheric inhomogeneities affect the results of comparison the radar images at HV and VH cross-polarizations. As a result, there is a problem of SAR signal polarization plane Faraday rotation angle measuring accuracy, which is needed for proper calibration of linearly polarized polarimetric long-wave band SAR using methods proposed by soviet and foreign specialists. Currently, there are no studies of Earth’s surfaces reflection properties carried out by means of space-based long-wave band polarimetric synthesized aperture radars at HV and VH polarizations. At the same time, the authors are not aware of any works, in which the reciprocity principle of cross-polarized HV and VH radar images is analyzed. An attempt to use aircraft P-band radar images at HV and VH polarizations for studying the reciprocity principle is performed in this work.

Phytochemical study of leaves of the genus <i>Syringa</i> L. species

The work is devoted to the phytochemical study of the leaves of various species of the genus Syringa. They are promising sources of raw material containing flavonoids. The leaves of S. vulgaris, S. josikaea, S. amurensis, S. microphylla, S. villosa and S. sweginzovii were selected for the experiment. Rutin was found in the studied extracts of lilac leaves. The bathochromic shift of the long-wave band in the UV spectra of the solutions of the studied extracts indicates the presence of flavonoids. Under the conditions of differential spectrophotometry, the maximal absorption was detected at the range of 406-412 nm of plant raw material. The total flavonoids at the wavelength of 412 nm calculated on rutin in all the studied samples varies from 1.43% to 2.92%.

Spectrum calibration of the first hyperspectral infrared measurements from a geostationary platform: Method and preliminary assessment

AbstractThe level‐1 (L1) radiance spectra from the first Geostationary Interferometric InfraRed Sounder (GIIRS) have been publicly available since January 2019. On account of the inherent observation characteristics, operation modes, and capabilities, a complete spectrum calibration method of GIIRS/L1 products is originally proposed to form the latest version (V3) algorithm for implementation. Particularly, four targeted improvements in three aspects are independently established: subsample location alignment to yield integrated interferograms in both forward and backward directions with almost zero phase, rough spectral scale unification as well as accurate spectral scale correction to resolve spectral non‐uniformity due to a seriously asymmetric configuration of focal plane array, and an additional double‐reflected compensation to mitigate the influence of non‐ideal onboard blackbody reference upon radiometric accuracy. Preliminary assessments from both domestic and international sources indicate that the spectral and radiometric accuracies of the measured spectra from the latest GIIRS/L1 V3 algorithm show a well‐behaved performance in both longwave (LW) and midwave (MW) bands, that is, lower than 10 ppm of spectral scale errors, which is of sufficient accuracy for numerical weather prediction use, and around 1 K for most uncontaminated channels within the LW band. However, non‐linearity correction of interferograms and spectral quality improvements, especially for the MW band, should be developed further. In general, a feasible solution of spectrum calibration for a hyperspectral sounder on geostationary platform is provided in detail for reference, which is expected to benefit users of GIIRS data as well as designers responsible for L1 data processing of other similar sensors.