On the complexity of the boundary layer structure and aerosol vertical
                        distribution in the coastal Mediterranean regions: a case study

Pace, Giandomenico; Junkermann, W.; Vitali, Lina; Sarra, Alcide di; Meloni, Daniela; Cacciani, Marco; Cremona, Giuseppe; Iannarelli, Anna Maria; Zanini, Gabriele

doi:10.3402/tellusb.v67.27721

Cited by 15 publications

(9 citation statements)

References 54 publications

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“…x ARTS matches the a priori profile from 12 km of altitude upward and, below 9 km, it is consistent with the measurements of precipitable water vapor (PWV) collected by the HATPRO radiometer (Rose and Czekala, 2009;Pace et al, 2015) installed at the THAAO. This lower part of x ARTS is calculated according to x ARTS (from the ground to 9 km) = PWV Hatpro PWV Eu…”

Section: Forward Model and A Priori Profilessupporting

confidence: 55%

“…The forward model is provided by the ARTS software (Eriksson et al, 2011), which is tuned to reproduce the VESPA-22 measurement technique. In order to perform a realistic simulation of the troposphere, the PWV measured by the HATPRO radiometer (Rose and Czekala, 2009;Pace et al, 2015) operating side by side with VESPA-22 is taken into account in the forward model.…”

Section: Discussionmentioning

confidence: 99%

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VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

et al. 2018

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Abstract. The new ground-based 22 GHz spectrometer, VESPA-22 (water Vapor Emission Spectrometer for Polar Atmosphere at 22 GHz) measures the 22.23 GHz water vapor emission line with a bandwidth of 500 MHz and a frequency resolution of 31 kHz. The integration time for a measurement ranges from 6 to 24 h, depending on season and weather conditions. Water vapor spectra are collected using the beam-switching technique. VESPA-22 is designed to operate automatically with little maintenance; it employs an uncooled front-end characterized by a receiver temperature of about 180 K and its quasi-optical system presents a full width at half maximum of 3.5 • . Every 30 min VESPA-22 measures also the sky opacity using the tipping curve technique. The instrument calibration is performed automatically by a noise diode; the emission temperature of this element is estimated twice an hour by observing alternatively a black body at ambient temperature and the sky at an elevation of 60 • . The retrieved profiles obtained inverting 24 h integration spectra present a sensitivity larger than 0.8 from about 25 to 75 km of altitude during winter and from about 30 to 65 km during summer, a vertical resolution from about 12 to 23 km (depending on altitude), and an overall 1σ uncertainty lower than 7 % up to 60 km altitude and rapidly increasing to 20 % at 75 km.In July 2016, VESPA-22 was installed at the Thule High Arctic Atmospheric Observatory located at Thule Air Base (76.5 • N, 68.8 • W), Greenland, and it has been operating almost continuously since then. The VESPA-22 water vapor mixing ratio vertical profiles discussed in this work are obtained from 24 h averaged spectra and are compared with version 4.2 of concurrent Aura/Microwave Limb Sounder (MLS) water vapor vertical profiles. In the sensitivity range of VESPA-22 retrievals, the intercomparison from July 2016 to July 2017 between VESPA-22 dataset and Aura/MLS dataset convolved with VESPA-22 averaging kernels shows an average difference within 1.4 % up to 60 km altitude and increasing to about 6 % (0.2 ppmv) at 72 km.

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Section: Forward Model and A Priori Profilessupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

et al. 2018

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“…Junkermann, 2001;Meloni et al, 2003;Di Iorio et al, 2003;Pace et al, 2015) and eastern (e.g. Formenti et al, 2002;Dulac and Chazette, 2003) parts of the basin thus improving the description of the atmospheric composition and structure over the whole Mediterranean area.…”

Section: Discussionmentioning

confidence: 99%

“…Aitken particle profiles are very rare over the sea surface in the Mediterranean (e.g. Junkermann et al, 2001;Pace et al, 2015) and data comparison is quite difficult. A few studies have observed NPF in the FT in continental areas Rose et al, 2015) and suggest that the export of pollution into the upper troposphere, as is common in the western basin, might promote the occurrence of these events.…”

Section: Discussionmentioning

confidence: 99%

Continental pollution in the western Mediterranean basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

et al. 2015

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Abstract. In this study we present airborne observations of aerosol and trace gases obtained over the sea in the western Mediterranean basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summer 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m above sea level over an extended area (40-45 • N and 2 • W-12 • E) including the Gulf of Genoa, southern France, the Gulf of Lion, and the Spanish coast. During TRAQA and SAFMED the study area experienced a wide range of meteorological conditions which favoured pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study show that continental pollution largely affects the western Mediterranean both close to coastal regions and in the open sea as far as ∼ 250 km from the coastline. The measured aerosol scattering coefficient varies between ∼ 20 and 120 Mm −1 , while carbon monoxide (CO) and ozone (O 3 ) mixing ratios are in the range of 60-165 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 µm) and accumulation (0.1-1.0 µm) modes is between ∼ 30 and 5000-6000 scm −3 (standard cm −3 ), which is comparable to the aerosol concentration measured in continental areas under pollution conditions. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 scm −3 ) observed both close to the surface and in the free troposphere, possibly linked to the influence of new particle formation (NPF) episodes over the basin.

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“…The profile is the profile used in the forward model calculations to compute the apriori spectrum and the weighting functions. matches the apriori profile from 12 km of altitude upward and, below 9 km, it is consistent with the measurements of precipitable water vapor (PWV) collected by the HATPRO radiometer (Rose and Czekala, 2009;Pace et al, 2015) The pressure and temperature profiles needed to run the forward calculation are built merging NASA Goddard Space Flight Center (GSFC), AURA/MLS and climatological temperature and pressure profiles. The NASA GSFC profiles by Goddard…”

Section: Distribution 10mentioning

confidence: 59%

VESPA-22: a ground-based microwave spectrometer for long-term measurements of Polar stratospheric water vapor

Mevi¹,

Muscari²,

Bertagnolio³

et al. 2017

Preprint

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Abstract. The new ground-based 22 GHz spectrometer, VESPA-22 (water Vapor Emission Spectrometer for PolarAtmosphere at 22 GHz) measures the 22.23 GHz water vapor emission line with a bandwith of 500 MHz and a frequency resolution of 31 kHz. The integration time for a measurement is of the order of hours, depending on season and weather conditions. Water vapor spectra are collected using the beam switching technique. VESPA-22 is designed to operate 15 automatically with minimum need of maintenance; it employs an uncooled front-end characterized by a receiver temperature of about 180 K and its quasi-optical system presents a half power full beam angle of 3.5°. VESPA-22 measures also the sky opacity with a temporal resolution of two measurements an hour using the tipping curve technique. The instrument calibration is performed automatically by a noise diode; the emission temperature of this element is measured two times an hour through the observation of a black body at ambient temperature and of the sky at 60° of elevation. The retrieved profiles 20 obtained inverting a 24-hour integration spectra present a sensitivity higher than 0.8 from about 25 to 72 km of altitude, a vertical resolution from about 12 to 23 km (depending on altitude) and an overall 1 uncertainty between 5 and 12 %.In July 2016, VESPA-22 was installed at the THAAO (Thule High Arctic Atmospheric Observatory) located at Thule Air Base (76.5° N, 68.8° W), Greenland, and has been operating almost continuously since then, with very few interruption periods characterized by poor weather. The VESPA-22 water vapor mixing ratio vertical profiles discussed in this work 25 cover the period from July 2016 to May 2017 and are compared with Version 4.2 of concurrent Aura/MLS (Waters et al., 2006) water vapor vertical profiles. In the sensitivity range of VESPA-22 retrievals, the intercomparison between the VESPA-22 dataset and Aura/MLS dataset convolved with VESPA-22 averaging kernels reveals a correlation coefficient of about 0.9 or higher and an average difference reaching its maximum of -6% or -0.2 ppmv at the top of the sensitivity range.Atmos. Meas. Tech. Discuss., https://doi

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On the complexity of the boundary layer structure and aerosol vertical distribution in the coastal Mediterranean regions: a case study

Cited by 15 publications

References 54 publications

VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

Continental pollution in the western Mediterranean basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

VESPA-22: a ground-based microwave spectrometer for long-term measurements of Polar stratospheric water vapor

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