The world’s highest levels of surface UV

Cordero, Raúl R.; Seckmeyer, Günther; Damiani, Alessandro; Riechelmann, Stefan; Rayas, J. A.; Labbé, Fernando; Laroze, David

doi:10.1039/c3pp50221j

Cited by 70 publications

(57 citation statements)

References 62 publications

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“…), belonging to the ESR European SKYNET network, under comparable (austral) summer conditions (i.e., on 24 January 2017). Details on the state-of-the-art measurements of SW radiation recorded there, their comparison with other stations and radiative transfer simulations, and the influence of the altitude on the solar irradiance can be found in Cordero et al (2014Cordero et al ( , 2016. In this location, a single RE episode, with flux approaching 300 W m −2 greater than the simulated clear-sky flux, developed between 08:00 and 11:30 and was characterized by an average irradiance greater than the solar constant.…”

Section: Validations Under All-sky Conditionsmentioning

confidence: 99%

Evaluation of Himawari-8 surface downwelling solar radiation by ground-based measurements

et al. 2018

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Abstract. Observations from the new Japanese geostationary satellite Himawari-8 permit quasi-real-time estimation of global shortwave radiation at an unprecedented temporal resolution. However, accurate comparisons with groundtruthing observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 global radiation product AMATERASS using observations recorded at four SKYNET stations in Japan and, for certain analyses, from the surface network of the Japanese Meteorological Agency in 2016. We found that the spatiotemporal variability of the satellite estimates was smaller than that of the ground observations; variability decreased with increases in the time step and spatial domain. Cloud variability was the main source of uncertainty in the satellite radiation estimates, followed by direct effects caused by aerosols and bright albedo. Under all-sky conditions, good agreement was found between satellite and ground-based data, with a mean bias in the range of 20-30 W m −2 (i.e., AMATERASS overestimated ground observations) and a root mean square error (RMSE) of approximately 70-80 W m −2 . However, results depended on the time step used in the validation exercise, on the spatial domain, and on the different climatological regions. In particular, the validation performed at 2.5 min showed largest deviations and RMSE values ranging from about 110 W m −2 for the mainland to a maximum of 150 W m −2 in the subtropical region. We also detected a limited overestimation in the number of clear-sky episodes, particularly at the pixel level. Overall, satellite-based estimates were higher under overcast conditions, whereas frequent episodes of cloud-induced enhanced surface radiation (i.e., measured radiation was greater than expected clear-sky radiation) tended to reduce this difference. Finally, the total mean bias was approximately 10-15 W m −2 under clear-sky conditions, mainly because of overall instantaneous direct aerosol forcing efficiency in the range of 120-150 W m −2 per unit of aerosol optical depth (AOD). A seasonal anticorrelation between AOD and global radiation differences was evident at all stations and was also observed within the diurnal cycle.

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Section: Validations Under All-sky Conditionsmentioning

confidence: 99%

Evaluation of Himawari-8 surface downwelling solar radiation by ground-based measurements

et al. 2018

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“…Few aerosol observations are available for the central volcanic zone of the Andes. An indication for the aerosol loading can be found in the observations by Cordero et al (2014). For January 15, 2013 the authors derived a total UV aerosol loading AOD = 0.15 and a single-scattering albedo SSA = 0.7 on the Chajnantor plateau (23°00′S, 67°45′W, 5100 m).…”

Section: Retrieval Of So 2 Fluxesmentioning

confidence: 98%

First estimates of fumarolic SO 2 fluxes from Putana volcano, Chile, using an ultraviolet imaging camera

Stebel

Amigo²,

Thomas

et al. 2015

Journal of Volcanology and Geothermal Research

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Putana is a stratovolcano in the central Andes volcanic zone in northern Chile on the border with Bolivia. Fumarolic activiy has been visible at its summit crater at 5890 m altitude from long distances since the early 1800s. However, due to its remote location neither detailed geological studies have been made nor gas fluxes have been monitored and therefore its evolution remains unknown. On November 28, 2012 an ultraviolet (UV) imaging camera was transported to Putana and for about 30 min images of the fumaroles were recorded at 12 Hz. These observations provide the first measurements of SO 2 fluxes from the fumarolic field of Putana and demonstrate the applicability of the UV camera to detect such emissions. The measurement series was used to assess whether the sampling rate of the data influences the estimate of the gas flux. The results suggest that measurements made at 10 s and 1 min intervals capture the inherent (turbulent) variability in both the plume/wind speed and SO 2 flux. Relatively high SO 2 fluxes varying between 0.3 kg s −1 and 1.4 kg s −1 , which translates to 26 t/day and 121 t/day assuming constant degassing throughout the day, were observed on November 28, 2012. Furthermore, we demonstrate how an optical flow algorithm can be integrated with the SO 2 retrieval to calculate SO 2 fluxes at pixel level. Average values of 0.64 kg s −1 ± 0.20 kg s −1 and 0.70 kg s −1 ± 0.53 kg s −1 were retrieved from a "classical" transect method and the "advanced" optical flow based retrieval, respectively. Assuming constant emissions throughout all times, these values would results in an average annual SO 2 burden of 20-22 kT.

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“…), belonging to the ESR European Skynet network, under comparable (austral) summer conditions (i.e., on 24 January, 2017). Details on the state-of-the-art measurements of shortwave radiation recorded there, on their 25 comparison with other stations and radiative transfer simulations as well as details on the influence of the altitude on the solar irradiance can be found in Cordero et al (2014Cordero et al ( , 2016. In this location, a single RE episode, with flux approaching 300 W/m 2 greater than the simulated clear-sky flux, developed between 8:00 and 11.30 A.M. and was characterised by an average irradiance greater than the solar constant.…”

Section: Validations Under All-sky Conditionsmentioning

confidence: 99%

Evaluation of Himawari-8 surface downwelling solar radiation by SKYNET observations

Damiani

Irie

Horio

et al. 2018

Preprint

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Abstract.Observations from the new Japanese geostationary satellite Himawari-8 permit quasi-real-time estimation of global shortwave radiation at an unprecedented temporal resolution. However, accurate comparisons with ground truthing observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 global radiation product AMATERASS using observations recorded at four SKYNET stations in Japan and, for certain analyses, from the surface 15 network of the Japanese Meteorological Agency in 2016. We found that the spatiotemporal variability of the satellite estimates was smaller than that of the ground observations; variability decreased with increases in the time step and spatial domain. Cloud variability was the main source of uncertainty in the satellite radiation estimates, followed by direct effects caused by aerosols and bright albedo. Under all-sky conditions, good agreement was found between satellite and groundbased data, with a mean bias in the range of 20-30 W/m 2 (i.e., AMATERASS overestimated ground observations) and a root 20 mean square error of approximately 80 W/m 2 . However, results depended on the time step used in the validation exercise and on the spatial domain. We also detected a limited overestimation in the number of clear-sky episodes, particularly at the pixel level. Overall, satellite-based estimates were higher under overcast conditions, whereas frequent episodes of cloudinduced enhanced surface radiation (i.e., measured radiation was greater than expected clear-sky radiation) tended to reduce this difference. Finally, the total mean bias was reduced to approximately 10-15 W/m 2 under clear-sky conditions, mainly 25 because of overall instantaneous direct aerosol forcing efficiency in the range of 120-150 W/m 2 per unit of aerosol optical depth (AOD). A seasonal anti-correlation between AOD and global radiation differences was evident at all stations and was also observed within the diurnal cycle.

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The world’s highest levels of surface UV

Cited by 70 publications

References 62 publications

Evaluation of Himawari-8 surface downwelling solar radiation by ground-based measurements

Evaluation of Himawari-8 surface downwelling solar radiation by ground-based measurements

First estimates of fumarolic SO 2 fluxes from Putana volcano, Chile, using an ultraviolet imaging camera

Evaluation of Himawari-8 surface downwelling solar radiation by SKYNET observations

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