Characterization and verification of ACAM slit functions for trace-gas retrievals during the 2011 DISCOVER-AQ flight campaign

Abstract. The Airborne Compact Atmospheric Mapper (ACAM), an ultraviolet/visible/near-infrared spectrometer, has been flown on board the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaigns to provide remote sensing observations of tropospheric and boundary-layer pollutants from its radiance measurements. To assure the trace-gas retrieval from ACAM measurements we perform detailed characterization and verification of ACAM slit functions. The wavelengths and slit functions of ACAM measurements are characterized for the air-quality channel (~304–500 nm) through cross-correlation with a high-resolution solar irradiance reference spectrum after necessarily accounting for atmospheric gas absorption and the ring effect in the calibration process. The derived slit functions, assuming a hybrid combination of asymmetric Gaussian and top-hat slit functions, agree very well with the laboratory-measured slit functions. Comparisons of trace-gas retrievals between using derived and measured slit functions demonstrate that the cross-correlation technique can be reliably used to characterize slit functions for trace-gas retrievals.

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Characterization and verification of ACAM slit functions for trace gas retrievals during the 2011 DISCOVER-AQ flight campaign

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-11415-2014 ◽

2014 ◽

Vol 7 (11) ◽

pp. 11415-11437

Author(s):

C. Liu ◽

X. Liu ◽

M. G. Kowalewski ◽

S. J. Janz ◽

G. González Abad ◽

...

Keyword(s):

Air Quality ◽

Cross Correlation ◽

Near Infrared ◽

Gas Absorption ◽

Trace Gas ◽

Correlation Technique ◽

Reference Spectrum ◽

Infrared Spectrometer ◽

Cross Correlation Technique ◽

Near Infrared Spectrometer

Abstract. The Airborne Compact Atmospheric Mapper (ACAM), an ultraviolet/visible/near-infrared spectrometer, has been flown on board the NASA UC-12 aircraft during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) campaigns to provide remote sensing observations of tropospheric and boundary layer pollutants from its radiance measurements. To improve the trace gas retrieval from ACAM measurements, we perform detailed characterization and verification of ACAM slit functions. The wavelengths and slit functions of ACAM measurements are characterized for the air quality channel (~304–500 nm) through cross-correlation with a high-resolution solar irradiance reference spectrum after necessarily accounting for atmospheric gas absorption and the Ring effect in the calibration process. The derived slit functions, assuming a hybrid combination of asymmetric Gaussian and top-hat slit functions, agree very well with the laboratory-measured slit functions. Comparisons of trace gas retrievals between using derived and measured slit functions demonstrate that the cross-correlation technique can be reliably used to characterize slit functions for trace gas retrievals.

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The emergence of the red sequence at z~2 seen through galaxy clustering in the UKIDSS UDS

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313004456 ◽

2012 ◽

Vol 8 (S295) ◽

pp. 105-108

Author(s):

William G. Hartley ◽

Omar Almaini ◽

Alice Mortlock ◽

Chris Conselice ◽

Keyword(s):

Dark Matter ◽

Cross Correlation ◽

Near Infrared ◽

Correlation Technique ◽

Dark Matter Halos ◽

Star Forming ◽

Deep Survey ◽

Cross Correlation Technique ◽

Infrared Survey

AbstractWe use the UKIDSS Ultra-Deep Survey, the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and passive galaxies to z ~ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter halos with Mhalo > 1013 M⊙ irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies.

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SuperCLASS – I. The super cluster assisted shear survey: Project overview and data release 1

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa709 ◽

2020 ◽

Vol 495 (2) ◽

pp. 1706-1723 ◽

Cited By ~ 1

Author(s):

Richard A Battye ◽

Michael L Brown ◽

Caitlin M Casey ◽

Ian Harrison ◽

Neal J Jackson ◽

...

Keyword(s):

Cross Correlation ◽

Near Infrared ◽

Correlation Technique ◽

Large Array ◽

Photometric Redshifts ◽

Very Large Array ◽

Infrared Observations ◽

Data Release ◽

L Band ◽

Cross Correlation Technique

ABSTRACT The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4 GHz) to a r.m.s. of $7\, \mu {\rm Jy}\,$beam−1 over an area of $\sim 1\, {\rm deg}^2$ centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements with the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity out to z ∼ 1. In this paper we give an overview of the project including the science goals and multiwavelength coverage before presenting the first data release. We have analysed around 400 h of e-MERLIN data allowing us to create a Data Release 1 (DR1) mosaic of $\sim 0.26\, {\rm deg}^2$ to the full depth. These observations have been supplemented with complementary radio observations from the Karl G. Jansky Very Large Array (VLA) and optical/near infrared observations taken with the Subaru, Canada-France-Hawaii, and Spitzer Telescopes. The main data product is a catalogue of 887 sources detected by the VLA, of which 395 are detected by e-MERLIN and 197 of these are resolved. We have investigated the size, flux, and spectral index properties of these sources finding them compatible with previous studies. Preliminary photometric redshifts, and an assessment of galaxy shapes measured in the radio data, combined with a radio-optical cross-correlation technique probing cosmic shear in a supercluster environment, are presented in companion papers.

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Classification of Red Oak (Quercus Rubra) and White Oak (Quercus Alba) Wood Using a near Infrared Spectrometer and Soft Independent Modelling of Class Analogies

Journal of Near Infrared Spectroscopy ◽

10.1255/jnirs.760 ◽

2008 ◽

Vol 16 (1) ◽

pp. 49-57 ◽

Cited By ~ 29

Author(s):

Oluwatosin Emmanuel Adedipe ◽

Ben Dawson-Andoh ◽

Jeffrey Slahor ◽

Larry Osborn

Keyword(s):

Near Infrared ◽

Quercus Rubra ◽

Red Oak ◽

Quercus Alba ◽

White Oak ◽

Infrared Spectrometer ◽

Near Infrared Spectrometer

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The Improvement on the Performance of DMD Hadamard Transform Near-Infrared Spectrometer by Double Filter Strategy and a New Hadamard Mask

Micromachines ◽

10.3390/mi10020149 ◽

2019 ◽

Vol 10 (2) ◽

pp. 149 ◽

Cited By ~ 1

Author(s):

Zifeng Lu ◽

Jinghang Zhang ◽

Hua Liu ◽

Jialin Xu ◽

Jinhuan Li

Keyword(s):

Near Infrared ◽

Signal To Noise Ratio ◽

Nonuniform Distribution ◽

Stray Light ◽

Spectral Energy ◽

Hadamard Transform ◽

Digital Micromirror Device ◽

Infrared Spectrometer ◽

Near Infrared Spectrometer ◽

The Impact

In the Hadamard transform (HT) near-infrared (NIR) spectrometer, there are defects that can create a nonuniform distribution of spectral energy, significantly influencing the absorbance of the whole spectrum, generating stray light, and making the signal-to-noise ratio (SNR) of the spectrum inconsistent. To address this issue and improve the performance of the digital micromirror device (DMD) Hadamard transform near-infrared spectrometer, a split waveband scan mode is proposed to mitigate the impact of the stray light, and a new Hadamard mask of variable-width stripes is put forward to improve the SNR of the spectrometer. The results of the simulations and experiments indicate that by the new scan mode and Hadamard mask, the influence of stray light is restrained and reduced. In addition, the SNR of the spectrometer also is increased.

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Investigating the total antioxidant capacity of gluten-free grains with miniaturized near-infrared spectrometer

NIR news ◽

10.1177/0960336019861509 ◽

2019 ◽

Vol 30 (5-6) ◽

pp. 35-38

Author(s):

Verena Wiedemair ◽

Christian Wolfgang Huck

Keyword(s):

Antioxidant Capacity ◽

Total Antioxidant Capacity ◽

High Performance ◽

Near Infrared ◽

Least Squares Regression ◽

Test Set ◽

Total Antioxidant ◽

Infrared Spectrometer ◽

Near Infrared Spectrometer ◽

Infrared Instruments

The use of ever smaller near-infrared instruments is becoming more and more prevalent, since they are cheaper, more versatile and often advertised as high-performance spectrometer. The last claim is rarely verified by independent researchers, which is why the presented work evaluates the performance of three hand-held spectrometers in comparison to a benchtop instrument. Seventy-seven samples comprising buckwheat, millet and oat were investigated for their total antioxidant capacity using Folin–Ciocalteu and near-infrared spectroscopy. Partial least squares regression models were established using cross- and test set validation. Results showed that all instruments were able to predict total antioxidant capacity to some extent. The coefficients of determinations ranged from 0.823 to 0.951 for cross-validated and from 0.849 to 0.952 for test set validated models. Errors for cross-validated models ranged from 1.11 to 2.08 mgGAE/g and for test set validated models from 1.02 to 1.86 mgGAE/g.

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