Correction to “Optical properties of boreal forest fire smoke derived from Sun photometry” by N. T. O'Neill, T. F. Eck, B. N. Holben, A. Smirnov, A. Royer, and Z. Li

O’Neill, N. T.

doi:10.1029/2002jd002700

Cited by 13 publications

(7 citation statements)

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“…Quasi-continuous direct sun measurements, with a sampling interval of 5 to 15 minutes (under cloudless conditions), provide AOD and Angstrom exponent values (B. N. Holben et al, 1998;B. Holben et al, 2001) as well as the partition of AOD 500nm between fine and coarse mode particles using the SDA algorithm (N. O'Neill et al, 2003). Measurements are collected both in daylight and at night using lunar photometry (Barreto et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Growth and global persistence of stratospheric sulfate aerosols from the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption

Boichu

Grandin

Blarel

et al. 2023

Preprint

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Stratospheric sulfate aerosols play a key role on atmospheric chemistry and Earth’s radiation budget, but their size distribution, a critical parameter in climate models, is generally poorly-known. We address such gap for the 2022 Hunga Tonga-Hunga Ha’apai (HT-HH) volcanic eruption by exhaustively analyzing a set of satellite observations together with photometric ground observations from the worldwide open-access AERONET network. We document a rapid growth of HT-HH sulfate aerosols in the days following eruption, faster than observed for other stratospheric eruptions, likely due to the exceptional hydration of the stratosphere by this phreatomagmatic eruption. An unusual aerosol fine mode (peak radius in 0.3-0.5 microns) is identified at 20 stations of the southern hemisphere until May 2023 (time of writing). Nevertheless, 1.4 years after eruption, HT-HH sulfate aerosols remain smaller than 1991 Pinatubo particles. Smaller aerosols backscatter more efficiently visible light and sediment more slowly than larger particles, implying stronger and longer-lasting negative radiative forcing.

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Section: Introductionmentioning

confidence: 99%

Growth and global persistence of stratospheric sulfate aerosols from the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption

Boichu

Grandin

Blarel

et al. 2023

Preprint

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“…Even if the viewing geometry can be adapted to minimize uncertainty due to partially known aerosol properties, as shown in Figures 10, 11, it is necessary to document the presence of aerosol load during data acquisitions. This can easily be done from the measurements provided by the AERONET-OC network (Zibordi et al, 2009) for which measurements are routinely operated to provide spectral aerosol optical thickness (Zibordi et al, 2021) or further optical properties (Dubovik et al, 2000;O'Neill et al, 2003). For another important network called HYPERNETS, the installed system, the HYperspectral Pointable System for Terrestrial and Aquatic Radiometry (HYPSTAR), could also be used to concurrently monitor the aerosol optical properties but it is not currently the case for routine operation (Goyens et al, 2022).…”

Section: Aerosol Approachmentioning

confidence: 99%

Apparent surface-to-sky radiance ratio of natural waters including polarization and aerosol effects: implications for above-water radiometry

Harmel

2023

Front. Remote Sens.

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Above-water radiometry (AWR) methods have been developed to provide “ground-truth” (or fiducial) measurements for calibration and validation of the water color satellite missions. AWR is also an important tool for environmental survey from dedicated field missions. Under clear sky, the critical step of AWR is to retrieve the water-leaving radiance from radiometric measurements of the upward radiance that also includes the reflection of the direct sunlight and diffuse skylight reflected by the wind ruffled water surface toward the sensor. In order to correct for the surface reflection, sky radiance measurements are performed and converted into surface radiance through a factor often called “sea surface reflectance factor” or “effective Fresnel reflectance coefficient”. Based on theoretical and practical considerations, this factor was renamed surface-to-sky radiance ratio, Rss, to avoid misuse of the term reflectance as often encountered in the literature. Vector radiative transfer computations were performed over the spectral range 350–1,000 nm to provide angular values of Rss for a comprehensive set of aerosol loads and types (including maritime, continental desert and polluted models) and water surface roughness expressed in wave slope variances or in equivalent Cox-Munk wind speeds, for practical use. After separating direct and diffuse light components, it was shown that the spectral shape and amplitude of Rss are very sensitive to aerosol load and type even for extremely low values of the aerosol optical thickness. Uncertainty attached to Rss was computed based on propagation of errors made in aerosol and surface roughness parameters demonstrating the need to adapt the viewing geometry according to the Sun elevation and to associate concurrent aerosol measurements for optimal AWR protocols.

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“…Results from our SBIG seeing monitor have been presented at past meetings of the American Astronomical Society (O'Neill et al 2016(O'Neill et al , 2017. The median and mode of the expected FWHM distributions were found to be 3 5 and 2 7, respectively.…”

Section: Image Quality and Seeingmentioning

confidence: 83%

The Renovated Thacher Observatory and First Science Results

Swift¹,

Andersen

Arculli

et al. 2022

PASP

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Located on the campus of the Thacher School in Southern California, the Thacher Observatory has a legacy of astronomy research and education that dates back to the late 1950s. In 2016, the observatory was fully renovated with upgrades including a new 0.7 m telescope, a research grade camera, and a slit dome with full automation capabilities. The low-elevation site is bordered by the Los Padres National Forest and therefore affords dark to very dark skies allowing for accurate and precise photometric observations. We present a characterization of the site including sky brightness, weather, and seeing, and we demonstrate the on-sky performance of the facility. Our primary research programs are based around our multi-band photometric capabilities and include photometric monitoring of variable sources, a nearby supernova search and followup program, a quick response transient followup effort, and exoplanet and eclipsing binary light curves. Select results from these programs are included in this work which highlight the broad range of science available to an automated observatory with a moderately sized telescope.

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Correction to “Optical properties of boreal forest fire smoke derived from Sun photometry” by N. T. O'Neill, T. F. Eck, B. N. Holben, A. Smirnov, A. Royer, and Z. Li

Cited by 13 publications

References 0 publications

Growth and global persistence of stratospheric sulfate aerosols from the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption

Growth and global persistence of stratospheric sulfate aerosols from the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption

Apparent surface-to-sky radiance ratio of natural waters including polarization and aerosol effects: implications for above-water radiometry

The Renovated Thacher Observatory and First Science Results

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