Aircraft Instrument for Comprehensive Characterization of Aerosol Optical Properties, Part I: Wavelength-Dependent Optical Extinction and Its Relative Humidity Dependence Measured Using Cavity Ringdown Spectroscopy

Langridge, Justin M.; Richardson, M.; Lack, D. A.; Law, D. C.; Murphy, D. M.

doi:10.1080/02786826.2011.592745

Cited by 103 publications

(122 citation statements)

References 62 publications

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“…At an integration time of 10 s, both channels can achieve the standard deviation precision of 0.24 Mm −1 (1σ). This detection limit is similar to those achieved in other CRDS instruments using pulsed lasers and modulated diode lasers [3,8,9,28]. The ambient measurement signals, however, were noisier due to the fluctuations from wind, temperature, pressure (not maintained at a constant in our setup), etc.…”

Section: Ambient Measurementssupporting

confidence: 57%

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Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy

Liu

Zhang

2013

Chin. Sci. Bull.

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Accurate measurement of optical extinction of atmospheric aerosols is important for quantifying the direct climate effects of aerosols. A portable cavity ringdown spectrometer utilizing a modulated multimode blue diode laser (linewidth ~0.2 nm) is developed to measure the aerosol optical extinction. Laboratory generated ammonia sulfate particles (<1 μm in diameter) are characterized, with good agreements between the experimental measurements and Mie theory calculations. An optical extinction detection sensitivity of 0.24 Mm −1 (1σ) is achieved. Measurements of ambient aerosols are also carried out. This study demonstrates the feasibility of a compact, multimode diode laser cavity ringdown spectrometer for sensitive measurements of the optical extinction of atmospheric aerosols. aerosol, optical extinction, spectroscopy Citation:Liu Y D, Zhang J S. Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy.

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Section: Ambient Measurementssupporting

confidence: 57%

“…However, these setups required complex electronics to control the optical cavity length and to modulate the diode laser output in order to couple the cw diode laser radiation into the cavity. Only recently, an instrument utilizing multimode diode lasers was reported by Langridge et al [28].…”

mentioning

confidence: 99%

Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy

Liu

Zhang

2013

Chin. Sci. Bull.

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“…Cavity ring-down extinction: the b ext measurements at 405 and 532 nm were made using the UC Davis (UCD) twowavelength cavity ring-down photoacoustic spectrometer (CRD-PAS) instrument (Langridge et al, 2011;Lack et al, 2012). Full details of these measurements are available in Cappa et al (2016) and Atkinson et al (2015).…”

Section: Instruments Used At the T0 Site (American Rivermentioning

confidence: 99%

“…Extinction by aerosol particles is determined relative to this gas zero. The aerosol extinction is further corrected to account for the practical aspect that the complete mirror-to-mirror distance of the optical cavity is typically not filled with aerosols (to keep the mirrors clean) (Langridge et al, 2011). The former (zeroing) limits instrument precision and sometimes accuracy while the latter (path length) limits instrument accuracy.…”

Section: Estimation Of the Fine-mode Effective Radius -The Fine-mode mentioning

confidence: 99%

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

et al. 2018

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Abstract. Multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-sizerelated information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved finemode fraction and effective radius compare well with other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM 1 and PM 10 , although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of "fine" and "coarse" modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparison here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.

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“…Optical aerosol properties were provided by five instruments onboard the NOAA P-3. The Cavity Ring Down aerosol extinction Spectrometer (CRDS) [Langridge et al, 2011] measured total dry aerosol light extinction at 532, 405 and 662 nm and the dependence of extinction on relative humidity. The Photoacoustic Absorption Spectrometer (PAS) [Lack et al, 2012] measured total dry aerosol light absorption at the same wavelengths as the CRDS.…”

Section: Ancillary Instrumentsmentioning

confidence: 99%

Spectral aerosol direct radiative forcing from airborne radiative measurements during CalNex and ARCTAS

et al. 2012

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This study presents the aerosol radiative forcing derived from airborne measurements of shortwave spectral irradiance during the 2010 Research at the Nexus of Air Quality and Climate Change (CalNex). Relative forcing efficiency, the radiative forcing normalized by aerosol optical thickness and incident irradiance, is a means of comparing the aerosol radiative forcing for different conditions. In this study, it is used to put the aerosol radiative effects of an air mass in the Los Angeles basin in context with case studies from three field missions that targeted other regions and aerosol types, including a case study from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). For CalNex, we relied on irradiance measurements onboard the NOAA P‐3 aircraft during a flight on 19 May 2010 over a ground station. CalNex presented a difficulty for determining forcing efficiency since one of the input parameters, optical thickness, was not available from the same aircraft. However, extinction profiles were available from a nearby aircraft. An existing retrieval algorithm was modified to use those measurements as initial estimate for the missing optical thickness. In addition, single scattering albedo and asymmetry parameter (secondary products of the method), were compared with CalNex in situ measurements. The CalNex relative forcing efficiency spectra agreed with earlier studies that found this parameter to be constrained at each wavelength within 20% per unit of aerosol optical thickness at 500 nm regardless of aerosol type and experiment, except for highly absorbing aerosols sampled near Mexico City. The diurnally averaged below‐layer forcing efficiency integrated over the wavelength range of 350–700 nm for CalNex is estimated to be −58.6 ± 13.8 W/m2, whereas for the ARCTAS case it is −48.7 ± 11.5 W/m2.

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Aircraft Instrument for Comprehensive Characterization of Aerosol Optical Properties, Part I: Wavelength-Dependent Optical Extinction and Its Relative Humidity Dependence Measured Using Cavity Ringdown Spectroscopy

Cited by 103 publications

References 62 publications

Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy

Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

Spectral aerosol direct radiative forcing from airborne radiative measurements during CalNex and ARCTAS

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