Using bright sunshine at low-elevation angles to compile an historical record of the effect of aerosol on incoming solar radiation

Horseman, Andrew; MacKenzie, A. R.; Timmis, Roger

doi:10.1016/j.atmosenv.2008.06.033

Cited by 23 publications

(33 citation statements)

References 20 publications

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“…These four steps are detailed in the following sections. Our method is similar to the method of Horseman et al (2013), but there are also significant differences that will be highlighted below.…”

Section: Semiautomatic Methods For Reading the Burned Tracesmentioning

confidence: 99%

“…Similar to Horseman et al (2013), scanning the burned card is the first step of our method and the more time-consuming manual part. For this purpose we use a commercial scanner (model HP Scanjet 5590).…”

Section: Image Capturementioning

confidence: 99%

“…Unlike Horseman et al (2013), the positioning of the card within the image also requires some manual intervention. This is convenient for checking the scan and the image treatment and necessary to convert the image of the burned pixels into length (millimeters of width) and into time (minutes along the day).…”

Section: Image Positioningmentioning

confidence: 99%

“…Galindo Estrada and Fournier D'Albe (1960) applied a similar approach: they compared daily values of the mass loss of burned cards (which is related to the perforation of the card and thus to mean burn width) with pyrheliometer readings. The hypothesis of using the burn width of CSSRs to obtain DSI data has recently been revisited, and several studies have shown the potential of the burn width of CSSR cards as a proxy for DSI (e.g., Wood and Harrison, 2011;Horseman et al, 2013); however, here a more complete research is presented, comparing burn width and DSI for a relatively long period of time (2 years) and investigating results at high-temporal resolution. As long-term records of SD cards are available at some historical meteorological stations, e.g., Blue Hill Observatory in United States (Magee et al, 2014;Mike Iacono, personal communication, 2014), the reconstruction of DSI for these sites can reach more than 100 years from the present day.…”

Section: Introductionmentioning

confidence: 99%

“…For this purpose we use a commercial scanner (model HP Scanjet 5590). As sensors in image scanners alter with time and use, a method to calibrate the scanner must be applied regularly (Horseman et al, 2013). We use a standard image format, 24 bit RGB BMP (bitmap), and the same dimension (2340 × 1700 pixels) for all scans.…”

Section: Image Capturementioning

confidence: 99%

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Using digital image processing to characterize the Campbell–Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

et al. 2015

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Abstract. The Campbell-Stokes sunshine recorder (CSSR) has been one of the most commonly used instruments for measuring sunshine duration (SD) through the burn length of a given CSSR card. Many authors have used SD to obtain information about cloudiness and solar radiation (by using Ångström-Prescott type formulas), but the burn width has not been used systematically. In principle, the burn width increases for increasing direct beam irradiance. The aim of this research is to show the relationship between burn width and direct solar irradiance (DSI) and to prove whether this relationship depends on the type of CSSR and burning card. A method of analysis based on image processing of digital scanned images of burned cards is used. With this method, the temporal evolution of the burn width with 1 min resolution can be obtained. From this, SD is easily calculated and compared with the traditional (i.e., visual) determination. The method tends to slightly overestimate SD, but the thresholds that are used in the image processing could be adjusted to obtain an improved estimation. Regarding the burn width, experimental results show that there is a high correlation between two different models of CSSRs, as well as a strong relationship between burn widths and DSI at a hightemporal resolution. Thus, for example, hourly DSI may be estimated from the burn width with higher accuracy than based on burn length (for one of the CSSR, relative root mean squared error is 24 and 30 %, respectively; mean bias error is −0.6 and −30.0 W m −2 , respectively). The method offers a practical way to exploit long-term sets of CSSR cards to create long time series of DSI. Since DSI is affected by atmospheric aerosol content, CSSR records may also become a proxy measurement for turbidity and atmospheric aerosol loading.

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Section: Semiautomatic Methods For Reading the Burned Tracesmentioning

confidence: 99%

Section: Image Capturementioning

confidence: 99%

Section: Image Positioningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Image Capturementioning

confidence: 99%

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Using digital image processing to characterize the Campbell–Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

et al. 2015

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The cause of solar dimming and brightening at the Earth's surface during the last half century: Evidence from measurements of sunshine duration

Stanhill

Achiman

Rosa

et al. 2014

J. Geophys. Res. Atmos.

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Analysis of the Angstrom-Prescott relationship between normalized values of global radiation and sunshine duration measured during the last 50 years made at five sites with a wide range of climate and aerosol emissions showed few significant differences in atmospheric transmissivity under clear or cloud-covered skies between years when global dimming occurred and years when global brightening was measured, nor in most cases were there any significant changes in the parameters or in their relationships to annual rates of fossil fuel combustion in the surrounding 1°cells. It is concluded that at the sites studied changes in cloud cover rather than anthropogenic aerosols emissions played the major role in determining solar dimming and brightening during the last half century and that there are reasons to suppose that these findings may have wider relevance.

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The signal of aerosol‐induced changes in sunshine duration records: A review of the evidence

et al. 2014

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Aerosols play a significant yet complex and central role in the Earth's radiation budget, and knowledge of long-term changes in the atmospheric turbidity induced by aerosols is therefore fundamental for a better understanding of climate change. However, there is little available information on changes in aerosol concentration in the atmosphere, especially prior to the 1980s. The present paper reviews publications reporting the suitability of sunshine duration records with regard to detecting changes in atmospheric aerosols. Some of the studies reviewed propose methods for estimating aerosol-related magnitudes, such as turbidity, from sunshine deficit at approximately sunrise and sunset, when the impact of aerosols on the solar beam is more easily observed. In addition, there is abundant evidence that one cause of the decadal changes observed in sunshine duration records involves variations in atmospheric aerosol loading. Possible directions for future research are also suggested: in particular, detailed studies of the burn (not only its length but also its width) registered by means of Campbell-Stokes sunshine recorders may provide a way of creating time series of atmospheric aerosol loading metrics dating back to over 120 years from the present.

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Using bright sunshine at low-elevation angles to compile an historical record of the effect of aerosol on incoming solar radiation

Cited by 23 publications

References 20 publications

Using digital image processing to characterize the Campbell–Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

Using digital image processing to characterize the Campbell–Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

The cause of solar dimming and brightening at the Earth's surface during the last half century: Evidence from measurements of sunshine duration

The signal of aerosol‐induced changes in sunshine duration records: A review of the evidence

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