Validation of satellite-based noontime UVI with NDACC ground-based instruments: influence of topography, environment and satellite overpass time

Brogniez, Colette; Auriol, Frédérique; Deroo, Christine; Arola, Antti; Kujanpää, Jukka; Sauvage, Béatrice; Kalakoski, Niilo; Pitkänen, Mikko R. A.; Catalfamo, Maxime; Metzger, Jean‐Marc; Tournois, Guy; Conceicao, Pierre Da

doi:10.5194/acp-16-15049-2016

Cited by 24 publications

(34 citation statements)

References 27 publications

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“…OMTO3 was on average the lowest total ozone column, which led to the highest modelled values of UVI. Brogniez et al (2016) found that OMI-UVI products were higher than local measurements of UVI on Reunion Island with a mean relative bias of about 2 % and median relative bias of 4 %. OMI-UVI products are based on the OMTO3 product, but also take other OMI products (aerosols, surface albedo) into account (Krotkov et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…This spectroradiometer is composed of two monochromators and scans the wavelength range of 280-450 nm. According to Brogniez et al (2016), Bentham DTMc300 UVI measurements have an expected uncertainty of about 5 % for a coverage factor of 2. Recalibration is made every 3 to 4 months with a 150 W -ground-based measurements from the SAOZ (Système d'Analyse par Observation Zenithal) (Pommereau and Goutail, 1988) UV-visible spectrometer collocated with the Bentham,…”

Section: Data Setsmentioning

confidence: 99%

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Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

et al. 2018

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Abstract. Surface ultraviolet radiation (SUR) is not an increasing concern after the implementation of the Montreal Protocol and the recovery of the ozone layer (Morgenstern et al., 2008). However, large uncertainties remain in the prediction of future changes of SUR (Bais et al., 2015). Several studies pointed out that UV-B impacts the biosphere (Erickson et al., 2015), especially the aquatic system, which plays a central part in the biogeochemical cycle (Hader et al., 2007). It can affect phytoplankton productivity (Smith and Cullen, 1995). This influence can result in either positive or negative feedback on climate (Zepp et al., 2007).Global circulation model simulations predict an acceleration of the Brewer-Dobson circulation over the next century (Butchart, 2014), which would lead to a decrease in ozone levels in the tropics and an enhancement at higher latitudes (Hegglin and Shepherd, 2009). Reunion Island is located in the tropics (21 • S, 55 • E), in a part of the world where the amount of ozone in the ozone column is naturally low. In addition, this island is mountainous and the marine atmosphere is often clean with low aerosol concentrations. Thus, measurements show much higher SUR than at other sites at the same latitude or at midlatitudes. Ground-based measurements of SUR have been taken on Reunion Island by a Bentham DTMc300 spectroradiometer since 2009. This instrument is affiliated with the Network for the Detection of Atmospheric Composition Change (NDACC). In order to quantify the future evolution of SUR in the tropics, it is necessary to validate a model against present observations. This study is designed to be a preliminary parametric and sensitivity study of SUR modelling in the tropics.We developed a local parameterisation using the Tropospheric Ultraviolet and Visible Model (TUV; Madronich, 1993) and compared the output of TUV to multiple years of Bentham spectral measurements. This comparison started in early 2009 and continued until 2016.Only clear-sky SUR was modelled, so we needed to sort out the clear-sky measurements. We used two methods to detect cloudy conditions: the first was based on an observer's hourly report on the sky cover, while the second was based on applying Long and Ackerman (2000)'s algorithm to broadband pyranometer data to obtain the cloud fraction and then discriminating clear-sky windows on SUR measurements.Published by Copernicus Publications on behalf of the European Geosciences Union. Multiple model inputs were tested to evaluate the model sensitivity to different parameters such as total ozone column, aerosol optical properties, extraterrestrial spectrum or ozone cross section. For total column ozone, we used ground-based measurements from the SAOZ (Système d'Analyse par Observation Zénithale) spectrometer and satellite measurements from the OMI and SBUV instruments, while ozone profiles were derived from radiosoundings and the MLS ozone product. Aerosol optical properties came from a local aerosol climatology established using a Cimel photometer. Since the me...

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Section: Discussionmentioning

confidence: 99%

Section: Data Setsmentioning

confidence: 99%

Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

et al. 2018

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“…Similar positive biases with increasing cloudiness were also reported. 201,203 [206][207][208][209] that the highest UVI on Earth of greater than 20 occurs in Peru, Bolivia, and Chile at high elevations of the Andes Mountains during summer months ( Fig. 9).…”

Section: Satellite Validationmentioning

confidence: 99%

“…These small biases generally increase for all-sky conditions and are 9% at OHP and 11% at SDR. 201 A new dataset of UVI observations with broadband instruments at six locations in South Africa recently became available. 202 Time records at four of the six sites are as long as 21 years.…”

Section: Satellite Validationmentioning

confidence: 99%

Ozone—climate interactions and effects on solar ultraviolet radiation

Bais

Bernhard

McKenzie

et al. 2019

Photochem Photobiol Sci

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“…It could be attributable to the strong seasonal variability of UV at La Réunion and thus to the concentration of oxidants like hydroxyl radical. The maximum daily UV index measured in clear sky by the Bentham spectrometer (Brogniez et al, 2016) at the OPAR site of Saint-Denis (80 m a.s.l., Fig. 1) is consistent with this assumption.…”

Section: Examples Of Volcanic Plume Distribution and Chemical Propertiesmentioning

confidence: 99%

First results of the Piton de la Fournaise STRAP 2015 experiment: multidisciplinary tracking of a volcanic gas and aerosol plume

et al. 2017

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Abstract. The STRAP (Synergie Transdisciplinaire pour Répondre aux Aléas liés aux Panaches volcaniques) campaign was conducted over the entire year of 2015 to investigate the volcanic plumes of Piton de La Fournaise (La Réu-nion, France). For the first time, measurements at the local (near the vent) and at the regional scales were conducted around the island. The STRAP 2015 campaign has become possible thanks to strong cross-disciplinary collaboration between volcanologists and meteorologists. The main observations during four eruptive periods (85 days) are summarised. They include the estimates of SO 2 , CO 2 and H 2 O emissions, the altitude of the plume at the vent and over different areas of La Réunion Island, the evolution of the SO 2 concentration, the aerosol size distribution and the aerosol extinction profile. A climatology of the volcanic plume dispersion is also reported. Simulations and measurements show that the plumes formed by weak eruptions have a stronger interaction with the surface of the island. Strong SO 2 mixing ratio and particle concentrations above 1000 ppb and 50 000 cm −3 respectively are frequently measured over a distance of 20 km from Piton de la Fournaise. The measured aerosol size distribution shows the predominance of small particles in the volcanic plume. Several cases of strong nucleation of sulfuric acid have been observed within the plume and at the distal site of the Maïdo observatory. The STRAP 2015 campaign provides a unique set of multi-disciplinary data that can now be used by modellers to improve the numerical parameterisations of the physical and chemical evolution of the volcanic plumes.

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Validation of satellite-based noontime UVI with NDACC ground-based instruments: influence of topography, environment and satellite overpass time

Cited by 24 publications

References 27 publications

Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

Ultraviolet radiation modelling from ground-based and satellite measurements on Reunion Island, southern tropics

Ozone—climate interactions and effects on solar ultraviolet radiation

First results of the Piton de la Fournaise STRAP 2015 experiment: multidisciplinary tracking of a volcanic gas and aerosol plume

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