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Francisco Navas-Guzmán
Andalusian Institute for Earth System Research (IISTA-CEAMA), 18006, Granada, Spain

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Preprint content
Published: 02 March 2021
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This work focuses on the characterization of vertically-resolved aerosol hygroscopicity properties and their direct radiative effects through a unique combination of ground-based and airborne remote sensing measurements during the DISCOVER-AQ 2011 field campaign in the Washington D.C. – Baltimore metropolitan area. To that end, we combined measurements from a multiwavelength Raman lidar located at NASA Goddard Space Flight Center and the airborne NASA Langley HSRL-1 lidar system. In-situ measurements on board the P-3B airplane and ground-based AERONET-DRAGON served to validate and complement quantifications of aerosol hygroscopicity from lidar measurements and also to extend the study both temporally and spatially. The focus here is on the 22nd and 29th of July, 2011 which were very humid days and characterized by a stable atmosphere and increasing relative humidity with height in the planetary boundary layer (PBL). Combined lidar and radiosonde measurements allowed the retrieval of the Hänel hygroscopic growth factor which agreed with that obtained from airborne in-situ measurements, and also explained the significant increase of extinction and backscattering with height. Airborne measurements also confirmed aerosol hygroscopicity throughout the entire day in the PBL and identified sulfates and water soluble organic carbon as the main species of aerosol particles. The combined Raman and HSRL-1 measurements permitted the inversion for aerosol microphysical properties revealing an increase of particle radius with altitude consistent with hygroscopic growth. Aerosol hygroscopicity was identified as the main reason to explain aerosol optical depth increases during the day, particularly for fine mode particles. Lidar measurements were used as input to the libRadtram radiative transfer code to obtain vertically-resolved aerosol radiative effects and heating rates under dry and humid conditions, and the results reveal that aerosol hygroscopicity is responsible for larger cooling effects in the shortwave range (7–10 W/m2 depending on aerosol load) near the ground, while heating rates produced a warming of 0.12 K/day near the top of PBL where aerosol hygroscopic growth was highest.

ACS Style

Daniel Pérez-Ramírez; David N. Whiteman; Igor Veselovskii; Richard Ferrare; Gloria Titos; María José Granados-Muñoz; Guadalupe Sánchez-Hernández; Francisco Navas-Guzmán. Spatiotemporal changes in aerosol properties by hygroscopic growth and impacts on radiative forcing and heating rates during DISCOVER-AQ 2011. 2021, 2021, 1 -40.

AMA Style

Daniel Pérez-Ramírez, David N. Whiteman, Igor Veselovskii, Richard Ferrare, Gloria Titos, María José Granados-Muñoz, Guadalupe Sánchez-Hernández, Francisco Navas-Guzmán. Spatiotemporal changes in aerosol properties by hygroscopic growth and impacts on radiative forcing and heating rates during DISCOVER-AQ 2011. . 2021; 2021 ():1-40.

Chicago/Turabian Style

Daniel Pérez-Ramírez; David N. Whiteman; Igor Veselovskii; Richard Ferrare; Gloria Titos; María José Granados-Muñoz; Guadalupe Sánchez-Hernández; Francisco Navas-Guzmán. 2021. "Spatiotemporal changes in aerosol properties by hygroscopic growth and impacts on radiative forcing and heating rates during DISCOVER-AQ 2011." 2021, no. : 1-40.

Journal article
Published: 22 February 2021 in Atmospheric Measurement Techniques
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The Raman Lidar for Meteorological Observations (RALMO) is operated at the MeteoSwiss station of Payerne (Switzerland) and provides, amongst other products, continuous measurements of temperature since 2010. The temperature profiles are retrieved from the pure rotational Raman (PRR) signals detected around the 355 nm Cabannes line. The transmitter and receiver systems of RALMO are described in detail, and the reception and acquisition units of the PRR channels are thoroughly characterized. The FastCom P7888 card used to acquire the PRR signal, the calculation of the dead time and the desaturation procedure are also presented. The temperature profiles retrieved from RALMO PRR data during the period going from July 2017 to the end of December 2018 have been validated against two reference operational radiosounding systems (ORSs) co-located with RALMO, i.e. the Meteolabor SRS-C50 and the Vaisala RS41. The ORSs have also served to perform the calibration of the RALMO temperature during the validation period. The maximum bias (ΔTmax), mean bias (μ) and mean standard deviation (σ) of RALMO temperature Tral with respect to the reference ORS, Tors, are used to characterize the accuracy and precision of Tral along the troposphere. The daytime statistics provide information essentially about the lower troposphere due to lower signal-to-noise ratio. The ΔTmax, μ and σ of the differences ΔT=Tral-Tors are, respectively, 0.28, 0.02±0.1 and 0.62±0.03 K. The nighttime statistics provide information for the entire troposphere and yield ΔTmax=0.29 K, μ=0.05±0.34 K and σ=0.66±0.06 K. The small ΔTmax, μ and σ values obtained for both daytime and nighttime comparisons indicate the high stability of RALMO that has been calibrated only seven times over 18 months. The retrieval method can correct for the largest sources of correlated and uncorrelated errors, e.g. signal noise, dead time of the acquisition system and solar background. Especially the solar radiation (scattered into the field of view from the zenith angle Φ) affects the quality of PRR signals and represents a source of systematic error for the retrieved temperature. An imperfect subtraction of the background from the daytime PRR profiles induces a bias of up to 2 K at all heights. An empirical correction f(Φ) ranging from 0.99 to 1 has therefore been applied to the mean background of the PRR signals to remove the bias. The correction function f(Φ) has been validated against the numerical weather prediction model COSMO (Consortium for Small-scale Modelling), suggesting that f(Φ) does not introduce any additional source of systematic or random error to Tral. A seasonality study has been performed to help with understanding if the overall daytime and nighttime zero bias hides seasonal non-zero biases that cancel out when combined in the full dataset.

ACS Style

Giovanni Martucci; Francisco Navas-Guzmán; Ludovic Renaud; Gonzague Romanens; S. Mahagammulla Gamage; Maxime Hervo; Pierre Jeannet; Alexander Haefele. Validation of pure rotational Raman temperature data from the Raman Lidar for Meteorological Observations (RALMO) at Payerne. Atmospheric Measurement Techniques 2021, 14, 1333 -1353.

AMA Style

Giovanni Martucci, Francisco Navas-Guzmán, Ludovic Renaud, Gonzague Romanens, S. Mahagammulla Gamage, Maxime Hervo, Pierre Jeannet, Alexander Haefele. Validation of pure rotational Raman temperature data from the Raman Lidar for Meteorological Observations (RALMO) at Payerne. Atmospheric Measurement Techniques. 2021; 14 (2):1333-1353.

Chicago/Turabian Style

Giovanni Martucci; Francisco Navas-Guzmán; Ludovic Renaud; Gonzague Romanens; S. Mahagammulla Gamage; Maxime Hervo; Pierre Jeannet; Alexander Haefele. 2021. "Validation of pure rotational Raman temperature data from the Raman Lidar for Meteorological Observations (RALMO) at Payerne." Atmospheric Measurement Techniques 14, no. 2: 1333-1353.

Journal article
Published: 16 February 2021 in Atmospheric Chemistry and Physics
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Remote-sensing measurements by light detection and ranging (lidar) instruments are fundamental for the monitoring of altitude-resolved aerosol optical properties. Here we validate vertical profiles of aerosol backscatter coefficient (βaer) measured by two independent lidar systems using co-located balloon-borne measurements performed by Compact Optical Backscatter Aerosol Detector (COBALD) sondes. COBALD provides high-precision in situ measurements of βaer at two wavelengths (455 and 940 nm). The two analyzed lidar systems are the research Raman Lidar for Meteorological Observations (RALMO) and the commercial CHM15K ceilometer (Lufft, Germany). We consider in total 17 RALMO and 31 CHM15K profiles, co-located with simultaneous COBALD soundings performed throughout the years 2014–2019 at the MeteoSwiss observatory of Payerne (Switzerland). The RALMO (355 nm) and CHM15K (1064 nm) measurements are converted to 455 and 940 nm, respectively, using the Ångström exponent profiles retrieved from COBALD data. To account for the different receiver field-of-view (FOV) angles between the two lidars (0.01–0.02∘) and COBALD (6∘), we derive a custom-made correction using Mie-theory scattering simulations. Our analysis shows that both lidar instruments achieve on average a good agreement with COBALD measurements in the boundary layer and free troposphere, up to 6 km altitude. For medium-high-aerosol-content measurements at altitudes below 3 km, the mean ± standard deviation difference in βaer calculated from all considered soundings is −2 % ± 37 % (−0.018 ± 0.237 Mm−1 sr−1 at 455 nm) for RALMO−COBALD and +5 % ± 43 % (+0.009 ± 0.185 Mm−1 sr−1 at 940 mm) for CHM15K−COBALD. Above 3 km altitude, absolute deviations generally decrease, while relative deviations increase due to the prevalence of air masses with low aerosol content. Uncertainties related to the FOV correction and spatial- and temporal-variability effects (associated with the balloon's drift with altitude and different integration times) contribute to the large standard deviations observed at low altitudes. The lack of information on the aerosol size distribution and the high atmospheric variability prevent an accurate quantification of these effects. Nevertheless, the excellent agreement observed in individual profiles, including fine and complex structures in the βaer vertical distribution, shows that under optimal conditions, the discrepancies with the in situ measurements are typically comparable to the estimated statistical uncertainties in the remote-sensing measurements. Therefore, we conclude that βaer profiles measured by the RALMO and CHM15K lidar systems are in good agreement with in situ measurements by COBALD sondes up to 6 km altitude.

ACS Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Maxime Hervo; Alexander Haefele; Francisco Navas-Guzmán. Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements. Atmospheric Chemistry and Physics 2021, 21, 2267 -2285.

AMA Style

Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Maxime Hervo, Alexander Haefele, Francisco Navas-Guzmán. Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements. Atmospheric Chemistry and Physics. 2021; 21 (3):2267-2285.

Chicago/Turabian Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Maxime Hervo; Alexander Haefele; Francisco Navas-Guzmán. 2021. "Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements." Atmospheric Chemistry and Physics 21, no. 3: 2267-2285.

Preprint content
Published: 10 September 2020
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The RAman Lidar for Meteorological Observations (RALMO) is operated at the MeteoSwiss station of Payerne (Switzerland) and provides, amongst other products, continuous measurements of temperature since 2010. The temperature profiles are retrieved from the pure rotational Raman (PRR) signals detected around the 355-nm Cabannes line. The transmitter-receiver system of RALMO is described in detail and the reception and acquisition units of the PRR channels are thoroughly characterized. The FastCom P7888 card used to acquire the PRR signal, the calculation of the dead-time and the desaturation procedure are also presented. The temperature profiles retrieved from RALMO data during the period going from July 2017 to the end of December 2018 have been validated against two reference operational radiosounding systems (ORS) co-located with RALMO, i.e. the Meteolabor SRS-C50 and the Vaisala RS41. These radiosondes have also been used to perform seven calibrations during the validation period. The maximum bias (ΔTmax), mean bias (μ) and mean standard deviation (σ) of RALMO temperature Tral with respect to the reference ORS Tors are used to characterize the accuracy and precision of Tral in the troposphere. The ΔTmax, μ and σ of the daytime differences ΔT=Tral−Tors in the lower troposphere are 0.28 K, 0.02±0.1 K and 0.62±0.03 K, respectively. The nighttime differences suffer a mean bias of μ = 0.05±0.34 K, a mean standard deviation σ=0.66±0.06 , and a maximum bias ΔTmax=0.29 K over the whole troposphere. The small ΔTmax, μ and σ values obtained for both daytime and nighttime comparisons indicate the high stability of RALMO that has been calibrated only seven times over 18 months. The retrieval method can correct for the largest sources of correlated and uncorrelated errors, e.g. signal noise, dead-time of the acquisition system and solar background. Especially the solar radiation (scattered into the field of view from the Zenith angle Phi affects the quality of PRR signals and represents a source of systematic error for the retrieved temperature. An imperfect subtraction of the background from the daytime PRR profiles induces a bias of up to 2 K at all heights. An empirical correction f(Φ) ranging from 0.99 to 1, has therefore been applied to the mean background of the PRR signals to remove the bias. The correction function f(Φ) has been validated against the numerical weather prediction model COSMO suggesting that f(Φ) does not introduce any additional source of systematic or random error to Tral. A seasonality study has been performed to help understanding if the overall daytime and nighttime zero-bias hides seasonal non-zero biases that cancel out when combined in the full dataset. Finally, the validated RALMO temperature has been used in combination with the humidity profiles retrieved from RALMO to calculate the relative humidity and to perform a qualitative study of supersaturation occurring in liquid stratus clouds.

ACS Style

Giovanni Martucci; Francisco Navas-Guzman; Ludovic Renaud; Gonzague Romanens; S. Mahagammulla Gamage; Maxime Hervo; Pierre Jeannet; Alexander Haefele. Validation of temperature data from the RAman Lidar for Meteorological Observations (RALMO) at Payerne. An application to liquid cloud supersaturation. 2020, 2020, 1 -32.

AMA Style

Giovanni Martucci, Francisco Navas-Guzman, Ludovic Renaud, Gonzague Romanens, S. Mahagammulla Gamage, Maxime Hervo, Pierre Jeannet, Alexander Haefele. Validation of temperature data from the RAman Lidar for Meteorological Observations (RALMO) at Payerne. An application to liquid cloud supersaturation. . 2020; 2020 ():1-32.

Chicago/Turabian Style

Giovanni Martucci; Francisco Navas-Guzman; Ludovic Renaud; Gonzague Romanens; S. Mahagammulla Gamage; Maxime Hervo; Pierre Jeannet; Alexander Haefele. 2020. "Validation of temperature data from the RAman Lidar for Meteorological Observations (RALMO) at Payerne. An application to liquid cloud supersaturation." 2020, no. : 1-32.

Preprint content
Published: 06 May 2020
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ACS Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Alexander Haefele; Francisco Navas-Guzmán. Supplementary material to "Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements". 2020, 1 .

AMA Style

Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, Francisco Navas-Guzmán. Supplementary material to "Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements". . 2020; ():1.

Chicago/Turabian Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Alexander Haefele; Francisco Navas-Guzmán. 2020. "Supplementary material to "Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements"." , no. : 1.

Preprint content
Published: 06 May 2020
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Remote sensing measurements by light detection and ranging (lidar) instruments are fundamental for the monitoring of altitude-resolved aerosol optical properties. Here, we validate vertical profiles of aerosol backscatter coefficient (βaer) measured by two independent lidar systems using co-located balloon-borne measurements performed by Compact Optical Backscatter Aerosol Detector (COBALD) sondes. COBALD provides high-precision in-situ measurements of βaer at two wavelengths (455 and 940 nm). The two analyzed lidar systems are the research Raman Lidar for Meteorological Observations (RALMO) and the commercial CHM15K ceilometer (Lufft, Germany). We consider in total 17 RALMO and 31 CHM15K profiles, co-located with simultaneous COBALD soundings performed throughout the years 2014–2019 at the MeteoSwiss observatory of Payerne (Switzerland). The RALMO (355 nm) and CHM15K (1064 nm) measurements are converted to respectively 455 nm and 940 nm using the Angstrom exponent profiles retrieved from COBALD data. To account for the different receiver field of view (FOV) angles between the two lidars (0.01–0.02°) and COBALD (6°), we derive a custom-made correction using Mie-theory scattering simulations. Our analysis shows that both RALMO and CHM15K achieve a good agreement with COBALD measurements in the boundary layer and free troposphere, up to 6 km altitude, and including fine structures in the aerosol’s vertical distribution. For altitudes below 2 km, the mean ± standard deviation difference in βaer is + 6 % ± 40 % (+ 0.005 ± 0.319 Mm−1 sr−1) for RALMO – COBALD at 455 nm, and + 13 % ± 51 % (+ 0.038 ± 0.207 Mm−1 sr−1) for CHM15K – COBALD at 940 nm. The large standard deviations can be at least partly attributed to atmospheric variability effects, associated with the balloon’s horizontal drift with altitude (away from the lidar beam) and the different integration times of the two techniques. Combined with the high spatial and temporal variability of atmospheric aerosols, these effects often lead to a slight altitude displacement between aerosol backscatter features that are seen by both techniques. For altitudes between 2–6 km, the absolute standard deviations of both RALMO and CHM15K decrease (below 0.13 and 0.16 Mm−1sr−1, respectively), while their corresponding relative deviations increase (often exceeding 100 % COBALD of the signal). This is due to the low aerosol content (i.e. low absolute backscattered signal) in the free troposphere, and the vertically decreasing signal-to-noise ratio of the lidar measurements (especially CHM15K). Overall, we conclude that the βaer profiles measured by the RALMO and CHM15K lidar systems are in good agreement with in-situ measurements by COBALD sondes up to 6 km altitude.

ACS Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Alexander Haefele; Francisco Navas-Guzmán. Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements. 2020, 1 -31.

AMA Style

Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, Francisco Navas-Guzmán. Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements. . 2020; ():1-31.

Chicago/Turabian Style

Simone Brunamonti; Giovanni Martucci; Gonzague Romanens; Yann Poltera; Frank G. Wienhold; Alexander Haefele; Francisco Navas-Guzmán. 2020. "Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements." , no. : 1-31.

Journal article
Published: 05 March 2020 in Remote Sensing
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This work evaluates the Lidar-Radiometer Inversion Code (LIRIC) using sun-sky photometers located at different altitudes in the same atmospheric column. Measurements were acquired during an intensive observational period in summer 2012 at Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS)/Aerosol Robotic Network (AERONET) Granada (GRA; 37.16°N, 3.61°W, 680 m above sea level (a.s.l.)) and Cerro Poyos (CP; 37.11°N, 3.49°W, 1820 m a.s.l.) sites. Both stations operated AERONET sun-photometry, with an additional lidar system operating at Granada station. The extended database of simultaneous lidar and sun-photometry measurements from this study allowed the statistical analysis of vertically resolved microphysical properties retrieved with LIRIC, with 70% of the analyzed cases corresponding to mineral dust. Consequently, volume concentration values were 46 μm3/cm3 on average, with a value of ~30 μm3/cm3 corresponding to the coarse spheroid mode and concentrations below 10 μm3/cm3 for the fine and coarse spherical modes. According to the microphysical properties’ profiles, aerosol particles reached altitudes up to 6000 m a.s.l., as observed in previous studies over the same region. Results obtained from comparing the LIRIC retrievals from GRA and from CP revealed good agreement between both stations with differences within the expected uncertainties associated with LIRIC (15%). However, larger discrepancies were found for 10% of the cases, mostly due to the incomplete overlap of the lidar signal and/or to the influence of different aerosol layers advected from the local origin located between both stations, which is particularly important in cases of low aerosol loads. Nevertheless, the results presented here demonstrate the robustness and self-consistency of LIRIC and consequently its applicability to large databases such as those derived from ACTRIS-European Aerosol Research Lidar Network (EARLINET) observations.

ACS Style

María J. Granados-Muñoz; José Antonio Benavent-Oltra; Daniel Pérez-Ramírez; Hassan Lyamani; Juan Luis Guerrero-Rascado; Juan Antonio Bravo-Aranda; Francisco Navas-Guzmán; Antonio Valenzuela; Francisco José Olmo; Lucas Alados-Arboledas. Evaluation of LIRIC Algorithm Performance Using Independent Sun-Sky Photometer Data at Two Altitude Levels. Remote Sensing 2020, 12, 842 .

AMA Style

María J. Granados-Muñoz, José Antonio Benavent-Oltra, Daniel Pérez-Ramírez, Hassan Lyamani, Juan Luis Guerrero-Rascado, Juan Antonio Bravo-Aranda, Francisco Navas-Guzmán, Antonio Valenzuela, Francisco José Olmo, Lucas Alados-Arboledas. Evaluation of LIRIC Algorithm Performance Using Independent Sun-Sky Photometer Data at Two Altitude Levels. Remote Sensing. 2020; 12 (5):842.

Chicago/Turabian Style

María J. Granados-Muñoz; José Antonio Benavent-Oltra; Daniel Pérez-Ramírez; Hassan Lyamani; Juan Luis Guerrero-Rascado; Juan Antonio Bravo-Aranda; Francisco Navas-Guzmán; Antonio Valenzuela; Francisco José Olmo; Lucas Alados-Arboledas. 2020. "Evaluation of LIRIC Algorithm Performance Using Independent Sun-Sky Photometer Data at Two Altitude Levels." Remote Sensing 12, no. 5: 842.

Research article
Published: 13 December 2019 in Atmospheric Chemistry and Physics
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Six months of stratospheric aerosol observations with the European Aerosol Research Lidar Network (EARLINET) from August 2017 to January 2018 are presented. The decay phase of an unprecedented, record-breaking stratospheric perturbation caused by wildfire smoke is reported and discussed in terms of geometrical, optical, and microphysical aerosol properties. Enormous amounts of smoke were injected into the upper troposphere and lower stratosphere over fire areas in western Canada on 12 August 2017 during strong thunderstorm–pyrocumulonimbus activity. The stratospheric fire plumes spread over the entire Northern Hemisphere in the following weeks and months. Twenty-eight European lidar stations from northern Norway to southern Portugal and the eastern Mediterranean monitored the strong stratospheric perturbation on a continental scale. The main smoke layer (over central, western, southern, and eastern Europe) was found at heights between 15 and 20 km since September 2017 (about 2 weeks after entering the stratosphere). Thin layers of smoke were detected at heights of up to 22–23 km. The stratospheric aerosol optical thickness at 532 nm decreased from values > 0.25 on 21–23 August 2017 to 0.005–0.03 until 5–10 September and was mainly 0.003–0.004 from October to December 2017 and thus was still significantly above the stratospheric background (0.001–0.002). Stratospheric particle extinction coefficients (532 nm) were as high as 50–200 Mm−1 until the beginning of September and on the order of 1 Mm−1 (0.5–5 Mm−1) from October 2017 until the end of January 2018. The corresponding layer mean particle mass concentration was on the order of 0.05–0.5 µg m−3 over these months. Soot particles (light-absorbing carbonaceous particles) are efficient ice-nucleating particles (INPs) at upper tropospheric (cirrus) temperatures and available to influence cirrus formation when entering the tropopause from above. We estimated INP concentrations of 50–500 L−1 until the first days in September and afterwards 5–50 L−1 until the end of the year 2017 in the lower stratosphere for typical cirrus formation temperatures of −55 ∘C and an ice supersaturation level of 1.15. The measured profiles of the particle linear depolarization ratio indicated a predominance of nonspherical smoke particles. The 532 nm depolarization ratio decreased slowly with time in the main smoke layer from values of 0.15–0.25 (August–September) to values of 0.05–0.10 (October–November) and < 0.05 (December–January). The decrease of the depolarization ratio is consistent with aging of the smoke particles, growing of a coating around the solid black carbon core (aggregates), and thus change of the shape towards a spherical form. We found ascending aerosol layer features over the most southern European stations, especially over the eastern Mediterranean at 32–35∘ N, that ascended from heights of about 18–19 to 22–23 km from the beginning of October to the beginning of December 2017 (about 2 km per month). We discuss several transport and lifting mechanisms that may have had an impact on the found aerosol layering structures.

ACS Style

Holger Baars; Albert Ansmann; Kevin Ohneiser; Moritz Haarig; Ronny Engelmann; Dietrich Althausen; Ingrid Hanssen; Michael Gausa; Aleksander Pietruczuk; Artur Szkop; Iwona S. Stachlewska; Dongxiang Wang; Jens Reichardt; Annett Skupin; Ina Mattis; Thomas Trickl; Hannes Vogelmann; Francisco Navas-Guzmán; Alexander Haefele; Karen Acheson; Albert A. Ruth; Boyan Tatarov; Detlef Müller; Qiaoyun Hu; Thierry Podvin; Philippe Goloub; Igor Veselovskii; Christophe Pietras; Martial Haeffelin; Patrick Fréville; Michaël Sicard; Adolfo Comerón; Alfonso Javier Fernández García; Francisco Molero Menéndez; Carmen Córdoba-Jabonero; Juan Luis Guerrero-Rascado; Lucas Alados-Arboledas; Daniele Bortoli; Maria João Costa; Davide Dionisi; Gian Luigi Liberti; Xuan Wang; Alessia Sannino; Nikolaos Papagiannopoulos; Antonella Boselli; Lucia Mona; Giuseppe D'Amico; Salvatore Romano; Maria Rita Perrone; Livio Belegante; Doina Nicolae; Ivan Grigorov; Anna Gialitaki; Vassilis Amiridis; Ourania Soupiona; Alexandros Papayannis; Rodanthi-Elisaveth Mamouri; Argyro Nisantzi; Birgit Heese; Julian Hofer; Yoav Y. Schechner; Ulla Wandinger; Gelsomina Pappalardo. The unprecedented 2017–2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET. Atmospheric Chemistry and Physics 2019, 19, 15183 -15198.

AMA Style

Holger Baars, Albert Ansmann, Kevin Ohneiser, Moritz Haarig, Ronny Engelmann, Dietrich Althausen, Ingrid Hanssen, Michael Gausa, Aleksander Pietruczuk, Artur Szkop, Iwona S. Stachlewska, Dongxiang Wang, Jens Reichardt, Annett Skupin, Ina Mattis, Thomas Trickl, Hannes Vogelmann, Francisco Navas-Guzmán, Alexander Haefele, Karen Acheson, Albert A. Ruth, Boyan Tatarov, Detlef Müller, Qiaoyun Hu, Thierry Podvin, Philippe Goloub, Igor Veselovskii, Christophe Pietras, Martial Haeffelin, Patrick Fréville, Michaël Sicard, Adolfo Comerón, Alfonso Javier Fernández García, Francisco Molero Menéndez, Carmen Córdoba-Jabonero, Juan Luis Guerrero-Rascado, Lucas Alados-Arboledas, Daniele Bortoli, Maria João Costa, Davide Dionisi, Gian Luigi Liberti, Xuan Wang, Alessia Sannino, Nikolaos Papagiannopoulos, Antonella Boselli, Lucia Mona, Giuseppe D'Amico, Salvatore Romano, Maria Rita Perrone, Livio Belegante, Doina Nicolae, Ivan Grigorov, Anna Gialitaki, Vassilis Amiridis, Ourania Soupiona, Alexandros Papayannis, Rodanthi-Elisaveth Mamouri, Argyro Nisantzi, Birgit Heese, Julian Hofer, Yoav Y. Schechner, Ulla Wandinger, Gelsomina Pappalardo. The unprecedented 2017–2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET. Atmospheric Chemistry and Physics. 2019; 19 (23):15183-15198.

Chicago/Turabian Style

Holger Baars; Albert Ansmann; Kevin Ohneiser; Moritz Haarig; Ronny Engelmann; Dietrich Althausen; Ingrid Hanssen; Michael Gausa; Aleksander Pietruczuk; Artur Szkop; Iwona S. Stachlewska; Dongxiang Wang; Jens Reichardt; Annett Skupin; Ina Mattis; Thomas Trickl; Hannes Vogelmann; Francisco Navas-Guzmán; Alexander Haefele; Karen Acheson; Albert A. Ruth; Boyan Tatarov; Detlef Müller; Qiaoyun Hu; Thierry Podvin; Philippe Goloub; Igor Veselovskii; Christophe Pietras; Martial Haeffelin; Patrick Fréville; Michaël Sicard; Adolfo Comerón; Alfonso Javier Fernández García; Francisco Molero Menéndez; Carmen Córdoba-Jabonero; Juan Luis Guerrero-Rascado; Lucas Alados-Arboledas; Daniele Bortoli; Maria João Costa; Davide Dionisi; Gian Luigi Liberti; Xuan Wang; Alessia Sannino; Nikolaos Papagiannopoulos; Antonella Boselli; Lucia Mona; Giuseppe D'Amico; Salvatore Romano; Maria Rita Perrone; Livio Belegante; Doina Nicolae; Ivan Grigorov; Anna Gialitaki; Vassilis Amiridis; Ourania Soupiona; Alexandros Papayannis; Rodanthi-Elisaveth Mamouri; Argyro Nisantzi; Birgit Heese; Julian Hofer; Yoav Y. Schechner; Ulla Wandinger; Gelsomina Pappalardo. 2019. "The unprecedented 2017–2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET." Atmospheric Chemistry and Physics 19, no. 23: 15183-15198.

Journal article
Published: 17 September 2019 in Atmospheric Chemistry and Physics
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This study focuses on the analysis of aerosol hygroscopicity using remote sensing techniques. Continuous observations of aerosol backscatter coefficient (βaer), temperature (T) and water vapor mixing ratio (r) have been performed by means of a Raman lidar system at the aerological station of MeteoSwiss at Payerne (Switzerland) since 2008. These measurements allow us to monitor in a continuous way any change in aerosol properties as a function of the relative humidity (RH). These changes can be observed either in time at a constant altitude or in altitude at a constant time. The accuracy and precision of RH measurements from the lidar have been evaluated using the radiosonde (RS) technique as a reference. A total of 172 RS profiles were used in this intercomparison, which revealed a bias smaller than 4 % RH and a standard deviation smaller than 10 % RH between both techniques in the whole (in lower) troposphere at nighttime (at daytime), indicating the good performance of the lidar for characterizing RH. A methodology to identify situations favorable to studying aerosol hygroscopicity has been established, and the aerosol hygroscopicity has been characterized by means of the backscatter enhancement factor (fβ). Two case studies, corresponding to different types of aerosol, are used to illustrate the potential of this methodology. The first case corresponds to a mixture of rural aerosol and smoke particles (smoke mixture), which showed a higher hygroscopicity (fβ355=2.8 and fβ1064=1.8 in the RH range 73 %–97 %) than the second case, in which mineral dust was present (fβ355=1.2 and fβ1064=1.1 in the RH range 68 %–84 %). The higher sensitivity of the shortest wavelength to hygroscopic growth was qualitatively reproduced using Mie simulations. In addition, a good agreement was found between the hygroscopic analysis done in the vertical and in time for Case I, where the latter also allowed us to observe the hydration and dehydration of the smoke mixture. Finally, the impact of aerosol hygroscopicity on the Earth's radiative balance has been evaluated using the GAME (Global Atmospheric Model) radiative transfer model. The model showed an impact with an increase in absolute value of 2.4 W m−2 at the surface with respect to the dry conditions for the hygroscopic layer of Case I (smoke mixture).

ACS Style

Francisco Navas-Guzmán; Giovanni Martucci; Martine Collaud Coen; María José Granados-Muñoz; Maxime Hervo; Michael Sicard; Alexander Haefele. Characterization of aerosol hygroscopicity using Raman lidar measurements at the EARLINET station of Payerne. Atmospheric Chemistry and Physics 2019, 19, 11651 -11668.

AMA Style

Francisco Navas-Guzmán, Giovanni Martucci, Martine Collaud Coen, María José Granados-Muñoz, Maxime Hervo, Michael Sicard, Alexander Haefele. Characterization of aerosol hygroscopicity using Raman lidar measurements at the EARLINET station of Payerne. Atmospheric Chemistry and Physics. 2019; 19 (18):11651-11668.

Chicago/Turabian Style

Francisco Navas-Guzmán; Giovanni Martucci; Martine Collaud Coen; María José Granados-Muñoz; Maxime Hervo; Michael Sicard; Alexander Haefele. 2019. "Characterization of aerosol hygroscopicity using Raman lidar measurements at the EARLINET station of Payerne." Atmospheric Chemistry and Physics 19, no. 18: 11651-11668.

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Published: 23 July 2019
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Francisco Navas-Guzmán. Point-by-point-responses-to-comments-from-reviewer#1. 2019, 1 .

AMA Style

Francisco Navas-Guzmán. Point-by-point-responses-to-comments-from-reviewer#1. . 2019; ():1.

Chicago/Turabian Style

Francisco Navas-Guzmán. 2019. "Point-by-point-responses-to-comments-from-reviewer#1." , no. : 1.

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Published: 23 July 2019
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Francisco Navas-Guzmán. Point-by-point-responses-to-comments-from-reviewer#2. 2019, 1 .

AMA Style

Francisco Navas-Guzmán. Point-by-point-responses-to-comments-from-reviewer#2. . 2019; ():1.

Chicago/Turabian Style

Francisco Navas-Guzmán. 2019. "Point-by-point-responses-to-comments-from-reviewer#2." , no. : 1.

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Published: 18 July 2019
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Six months of stratospheric aerosol observations with the European Aerosol Research Lidar Network (EARLINET) from August 2017 to January 2018 are presented. The decay phase of an unprecedented, record-breaking stratospheric perturbation caused by wild fire smoke is reported and discussed in terms of geometrical, optical, and microphysical aerosol properties. Enormous amounts of smoke (mainly soot particles) were injected into the upper troposphere and lower stratosphere over fire areas in western Canada on 12 August 2017 during strong thunderstorm-pyrocumulonimbus activity. The stratospheric smoke plumes spread over the entire northern hemisphere in the following weeks and months. Twenty-eight European lidar stations from northern Norway to southern Portugal and the Eastern Mediterranean monitored the strong stratospheric perturbation on a continental scale. The main smoke layer (over central, western, southern, and eastern Europe) was found between 15 and 20 km height since September 2017 (about two weeks after entering the stratosphere). Thin layers of smoke were detected to ascent to 22–24 km height. The stratospheric aerosol optical thickness at 532 nm decreased from values > 0.25 on 21–23 August 2017 to 0.005–0.03 until 5–10 September, and was mainly 0.003–0.004 from October to December 2017, and thus still significantly above the stratospheric background (0.001–0.002). Stratospheric particle extinction coefficients (532 nm) were as high as 50–200 Mm−1 until the beginning of September and of the order of 1 Mm−1 (0.5–5 Mm−1) from October 2017 until the end of January 2018. The corresponding layer mean particle mass concentration was of the order of 0.05–0.5 μg cm−3 over the months. Soot is an efficient ice-nucleating particle (INP) at upper tropospheric (cirrus) temperatures and available to influence cirrus formation when entering the tropopause from above. We estimated INP concentrations of 50–500 L−1 until the first days in September and afterwards 5–50 L−1 until the end of the year 2018 in the lower stratosphere for typical cirrus formation temperatures of −55 °C and ice supersaturation values of 1.15. The measured profiles of the particle linear depolarization rato indicated the predominance of non-spherical soot particles. The 532 nm depolarization ratio decreased with time in the main smoke layer from values of 0.15–0.25 (August–September) to values of 0.05–0.10 (October–November) and

ACS Style

Holger Baars; Albert Ansmann; Kevin Ohneiser; Moritz Haarig; Ronny Engelmann; Dietrich Althausen; Ingrid Hanssen; Michael Gausa; Aleksander Pietruczuk; Artur Szkop; Iwona S. Stachlewska; Dongxiang Wang; Jens Reichhardt; Annett Skupin; Ina Mattis; Thomas Trickl; Hannes Vogelmann; Francisco Navas-Guzmán; Alexander Haefele; Karen Acheson; Albert A. Ruth; Boyan Tatarov; Detlef Müller; Qiaoyun Hu; Thierry Podvin; Philippe Goloub; Igor Vesselovski; Christophe Pietras; Martial Haeffelin; Patrick Fréville; Michaël Sicard; Adolfo Comerón; Alfonso Javier Fernández García; Francisco Molero Menéndez; Carmen Córdoba-Jabonero; Juan Luis Guerrero-Rascado; Lucas Alados-Arboledas; Daniele Bortoli; Maria João Costa; Davide Dionisi; Gian Luigi Liberti; Xuan Wang; Alessia Sannino; Nikolaos Papagiannopoulos; Antonella Boselli; Lucia Mona; Giuseppe D'amico; Salvatore Romano; Maria Rita Perrone; Livio Belegante; Doina Nicolae; Ivan Grigorov; Anna Gialitaki; Vassilis Amiridis; Ourania Soupiona; Alexandros Papayannis; Rodanthi-Elisaveth Mamouri; Argyro Nisantzi; Birgit Heese; Julian Hofer; Yoav Y. Schechner; Ulla Wandinger; Gelsomina Pappalardo. The unprecedented 2017–2018 stratospheric smoke event: Decay phase and aerosol properties observed with EARLINET. 2019, 1 .

AMA Style

Holger Baars, Albert Ansmann, Kevin Ohneiser, Moritz Haarig, Ronny Engelmann, Dietrich Althausen, Ingrid Hanssen, Michael Gausa, Aleksander Pietruczuk, Artur Szkop, Iwona S. Stachlewska, Dongxiang Wang, Jens Reichhardt, Annett Skupin, Ina Mattis, Thomas Trickl, Hannes Vogelmann, Francisco Navas-Guzmán, Alexander Haefele, Karen Acheson, Albert A. Ruth, Boyan Tatarov, Detlef Müller, Qiaoyun Hu, Thierry Podvin, Philippe Goloub, Igor Vesselovski, Christophe Pietras, Martial Haeffelin, Patrick Fréville, Michaël Sicard, Adolfo Comerón, Alfonso Javier Fernández García, Francisco Molero Menéndez, Carmen Córdoba-Jabonero, Juan Luis Guerrero-Rascado, Lucas Alados-Arboledas, Daniele Bortoli, Maria João Costa, Davide Dionisi, Gian Luigi Liberti, Xuan Wang, Alessia Sannino, Nikolaos Papagiannopoulos, Antonella Boselli, Lucia Mona, Giuseppe D'amico, Salvatore Romano, Maria Rita Perrone, Livio Belegante, Doina Nicolae, Ivan Grigorov, Anna Gialitaki, Vassilis Amiridis, Ourania Soupiona, Alexandros Papayannis, Rodanthi-Elisaveth Mamouri, Argyro Nisantzi, Birgit Heese, Julian Hofer, Yoav Y. Schechner, Ulla Wandinger, Gelsomina Pappalardo. The unprecedented 2017–2018 stratospheric smoke event: Decay phase and aerosol properties observed with EARLINET. . 2019; ():1.

Chicago/Turabian Style

Holger Baars; Albert Ansmann; Kevin Ohneiser; Moritz Haarig; Ronny Engelmann; Dietrich Althausen; Ingrid Hanssen; Michael Gausa; Aleksander Pietruczuk; Artur Szkop; Iwona S. Stachlewska; Dongxiang Wang; Jens Reichhardt; Annett Skupin; Ina Mattis; Thomas Trickl; Hannes Vogelmann; Francisco Navas-Guzmán; Alexander Haefele; Karen Acheson; Albert A. Ruth; Boyan Tatarov; Detlef Müller; Qiaoyun Hu; Thierry Podvin; Philippe Goloub; Igor Vesselovski; Christophe Pietras; Martial Haeffelin; Patrick Fréville; Michaël Sicard; Adolfo Comerón; Alfonso Javier Fernández García; Francisco Molero Menéndez; Carmen Córdoba-Jabonero; Juan Luis Guerrero-Rascado; Lucas Alados-Arboledas; Daniele Bortoli; Maria João Costa; Davide Dionisi; Gian Luigi Liberti; Xuan Wang; Alessia Sannino; Nikolaos Papagiannopoulos; Antonella Boselli; Lucia Mona; Giuseppe D'amico; Salvatore Romano; Maria Rita Perrone; Livio Belegante; Doina Nicolae; Ivan Grigorov; Anna Gialitaki; Vassilis Amiridis; Ourania Soupiona; Alexandros Papayannis; Rodanthi-Elisaveth Mamouri; Argyro Nisantzi; Birgit Heese; Julian Hofer; Yoav Y. Schechner; Ulla Wandinger; Gelsomina Pappalardo. 2019. "The unprecedented 2017–2018 stratospheric smoke event: Decay phase and aerosol properties observed with EARLINET." , no. : 1.

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Published: 15 April 2019
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This study focuses on the analysis of aerosol hygroscopicity using remote sensing technique. Continuous observations of aerosol backscatter coefficient, temperature and water vapour mixing ratio are performed by means of a Raman lidar system at the aerological station of MeteoSwiss at Payerne (Switzerland) since 2008. These measurements allow us to monitor in a continuous way any change of aerosol properties as a function of the relative humidity (RH). These changes can be observed either in time at constant altitude or in altitude at a constant time. The accuracy and precision of RH measurements from the lidar have been evaluated using the radiosonde (RS) technique as reference. A total of 172 RSs were used in this intercomparison which revealed a small bias (

ACS Style

Francisco Navas Guzmán; Giovanni Martucci; Martine Collaud Coen; María José Granados Muñoz; Maxime Hervo; Michael Sicard; Alexander Haefele. Towards continuous monitoring of aerosol hygroscopicity by Raman lidar measurements at the EARLINET station of Payerne. 2019, 2019, 1 -30.

AMA Style

Francisco Navas Guzmán, Giovanni Martucci, Martine Collaud Coen, María José Granados Muñoz, Maxime Hervo, Michael Sicard, Alexander Haefele. Towards continuous monitoring of aerosol hygroscopicity by Raman lidar measurements at the EARLINET station of Payerne. . 2019; 2019 ():1-30.

Chicago/Turabian Style

Francisco Navas Guzmán; Giovanni Martucci; Martine Collaud Coen; María José Granados Muñoz; Maxime Hervo; Michael Sicard; Alexander Haefele. 2019. "Towards continuous monitoring of aerosol hygroscopicity by Raman lidar measurements at the EARLINET station of Payerne." 2019, no. : 1-30.

Journal article
Published: 18 May 2018 in Atmospheric Chemistry and Physics
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This study focuses on the analysis of aerosol hygroscopic growth during the Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at the ACTRIS Granada station and in situ instrumentation at a mountain station (Sierra Nevada, SNS). To this end, a methodology based on simultaneous measurements of aerosol profiles from an EARLINET multi-wavelength Raman lidar (RL) and relative humidity (RH) profiles obtained from a multi-instrumental approach is used. This approach is based on the combination of calibrated water vapor mixing ratio (r) profiles from RL and continuous temperature profiles from a microwave radiometer (MWR) for obtaining RH profiles with a reasonable vertical and temporal resolution. This methodology is validated against the traditional one that uses RH from co-located radiosounding (RS) measurements, obtaining differences in the hygroscopic growth parameter (γ) lower than 5 % between the methodology based on RS and the one presented here. Additionally, during the SLOPE I campaign the remote sensing methodology used for aerosol hygroscopic growth studies has been checked against Mie calculations of aerosol hygroscopic growth using in situ measurements of particle number size distribution and submicron chemical composition measured at SNS. The hygroscopic case observed during SLOPE I showed an increase in the particle backscatter coefficient at 355 and 532 nm with relative humidity (RH ranged between 78 and 98 %), but also a decrease in the backscatter-related Ångström exponent (AE) and particle linear depolarization ratio (PLDR), indicating that the particles became larger and more spherical due to hygroscopic processes. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, and we found good agreement on γ measured with remote sensing (γ532=0.48±0.01 and γ355=0.40±0.01) with respect to the values calculated using Mie theory (γ532=0.53±0.02 and γ355=0.45±0.02), with relative differences between measurements and simulations lower than 9 % at 532 nm and 11 % at 355 nm.

ACS Style

Andrés Esteban Bedoya-Velásquez; Francisco Navas-Guzmán; María José Granados-Muñoz; Gloria Titos; Roberto Román; Juan Andrés Casquero-Vera; Pablo Ortiz-Amezcua; Jose Antonio Benavent-Oltra; Gregori De Arruda Moreira; Elena Montilla-Rosero; Carlos David Hoyos; Begoña Artiñano; Esther Coz; Francisco José Olmo Reyes; Lucas Alados-Arboledas; Juan Luis Guerrero-Rascado. Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in situ instrumentation. Atmospheric Chemistry and Physics 2018, 18, 7001 -7017.

AMA Style

Andrés Esteban Bedoya-Velásquez, Francisco Navas-Guzmán, María José Granados-Muñoz, Gloria Titos, Roberto Román, Juan Andrés Casquero-Vera, Pablo Ortiz-Amezcua, Jose Antonio Benavent-Oltra, Gregori De Arruda Moreira, Elena Montilla-Rosero, Carlos David Hoyos, Begoña Artiñano, Esther Coz, Francisco José Olmo Reyes, Lucas Alados-Arboledas, Juan Luis Guerrero-Rascado. Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in situ instrumentation. Atmospheric Chemistry and Physics. 2018; 18 (10):7001-7017.

Chicago/Turabian Style

Andrés Esteban Bedoya-Velásquez; Francisco Navas-Guzmán; María José Granados-Muñoz; Gloria Titos; Roberto Román; Juan Andrés Casquero-Vera; Pablo Ortiz-Amezcua; Jose Antonio Benavent-Oltra; Gregori De Arruda Moreira; Elena Montilla-Rosero; Carlos David Hoyos; Begoña Artiñano; Esther Coz; Francisco José Olmo Reyes; Lucas Alados-Arboledas; Juan Luis Guerrero-Rascado. 2018. "Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in situ instrumentation." Atmospheric Chemistry and Physics 18, no. 10: 7001-7017.

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Published: 21 December 2017
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This work focuses on the study of aerosol hygroscopic growth during Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at Granada valley station (IISTA-CEAMA station) and in-situ instrumentation at a mountain station (Sierra Nevada station, SNS), located ~ 20 km away from IISTA-CEAMA and about 1 km above this station. To this end, a methodology based on the combination of calibrated water vapour mixing ratio (r) profiles, retrieved from an EARLINET multiwavelength Raman lidar (RL), and continuous temperature profiles from a microwave radiometer (MWR) for obtaining relative humidity (RH) profiles with high temporal resolution is used. This methodology is validated against an approach using radiosounding (RS) data at the EARLINET IISTA-CEAMA station, achieving differences in hygroscopic growth parameter (γ) lower than 5 % between the methodology based on RS and that based on remote sensing. During SLOPE I the remote sensing methodology used for aerosol hygroscopic growth studies has been checked using Mie calculations with in-situ measurements at SNS. For SLOPE I case with remote sensing instrumentation, an increase in particle backscatter coefficient at 355 and 532 nm is observed from 1.5 to 2.4 km a.s.l. in the relative humidity range of 78–98 %, but also a decrease on Ångström exponent (AE) and particle linear depolarization ratio (PLDR). This fact indicates that particles become larger and more spherical as relative humidity increases, what is strongly related to aerosol hygroscopic growth. In addition, atmospheric stability is checked ensuring well-mixed layers. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system at IISTA-CEAMA station, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, obtaining relative differences between RL and Mie simulations up to 13 % and 10 % for 532 nm and 355 nm, respectively.

ACS Style

Andrés E. Bedoya-Velásquez; Francisco Navas-Guzmán; María J. Granados-Muñoz; Gloria Titos; Roberto Roman; Juan A. Casquero-Vera; Pablo Ortiz-Amezcua; Jose A. Benavent-Oltra; Gregory De Arruda Moreira; Elena Montilla-Rosero; Carlos D. Hoyos Ortiz; Begoña Artíñano; Esther Coz; Lucas Alados-Arboledas; Juan Luis Guerrero-Rascado. Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in-situ instrumentation. 2017, 2017, 1 -29.

AMA Style

Andrés E. Bedoya-Velásquez, Francisco Navas-Guzmán, María J. Granados-Muñoz, Gloria Titos, Roberto Roman, Juan A. Casquero-Vera, Pablo Ortiz-Amezcua, Jose A. Benavent-Oltra, Gregory De Arruda Moreira, Elena Montilla-Rosero, Carlos D. Hoyos Ortiz, Begoña Artíñano, Esther Coz, Lucas Alados-Arboledas, Juan Luis Guerrero-Rascado. Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in-situ instrumentation. . 2017; 2017 ():1-29.

Chicago/Turabian Style

Andrés E. Bedoya-Velásquez; Francisco Navas-Guzmán; María J. Granados-Muñoz; Gloria Titos; Roberto Roman; Juan A. Casquero-Vera; Pablo Ortiz-Amezcua; Jose A. Benavent-Oltra; Gregory De Arruda Moreira; Elena Montilla-Rosero; Carlos D. Hoyos Ortiz; Begoña Artíñano; Esther Coz; Lucas Alados-Arboledas; Juan Luis Guerrero-Rascado. 2017. "Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in-situ instrumentation." 2017, no. : 1-29.

Journal article
Published: 27 November 2017 in Atmospheric Chemistry and Physics
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In this work the stratospheric performance of a relatively new microwave temperature radiometer (TEMPERA) has been evaluated. With this goal in mind, almost 3 years of temperature measurements (January 2014–September 2016) from the TEMPERA radiometer were intercompared with simultaneous measurements from other techniques: radiosondes, MLS satellite and Rayleigh lidar. This intercomparison campaign was carried out at the aerological station of MeteoSwiss at Payerne (Switzerland). In addition, the temperature profiles from TEMPERA were used to validate the temperature outputs from the SD-WACCM model. The results showed in general a very good agreement between TEMPERA and the different instruments and the model, with a high correlation (higher than 0.9) in the temperature evolution at different altitudes between TEMPERA and the different data sets. An annual pattern was observed in the stratospheric temperature with generally higher temperatures in summer than in winter and with a higher variability during winter. A clear change in the tendency of the temperature deviations was detected in summer 2015, which was due to the repair of an attenuator in the TEMPERA spectrometer. The mean and the standard deviations of the temperature differences between TEMPERA and the different measurements were calculated for two periods (before and after the repair) in order to quantify the accuracy and precision of this radiometer over the campaign period. The results showed absolute biases and standard deviations lower than 2 K for most of the altitudes. In addition, comparisons proved the good performance of TEMPERA in measuring the temperature in the stratosphere.

ACS Style

Francisco Navas-Guzmán; Niklaus Kämpfer; Franziska Schranz; Wolfgang Steinbrecht; Alexander Haefele. Intercomparison of stratospheric temperature profiles from a ground-based microwave radiometer with other techniques. Atmospheric Chemistry and Physics 2017, 17, 14085 -14104.

AMA Style

Francisco Navas-Guzmán, Niklaus Kämpfer, Franziska Schranz, Wolfgang Steinbrecht, Alexander Haefele. Intercomparison of stratospheric temperature profiles from a ground-based microwave radiometer with other techniques. Atmospheric Chemistry and Physics. 2017; 17 (22):14085-14104.

Chicago/Turabian Style

Francisco Navas-Guzmán; Niklaus Kämpfer; Franziska Schranz; Wolfgang Steinbrecht; Alexander Haefele. 2017. "Intercomparison of stratospheric temperature profiles from a ground-based microwave radiometer with other techniques." Atmospheric Chemistry and Physics 17, no. 22: 14085-14104.

Journal article
Published: 17 November 2017 in Atmospheric Measurement Techniques
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Microwave radiometry is a suitable technique to measure atmospheric temperature profiles with high temporal resolution during clear sky and cloudy conditions. In this study, we included cloud models in the inversion algorithm of the microwave radiometer TEMPERA (TEMPErature RAdiometer) to determine the effect of cloud liquid water on the temperature retrievals. The cloud models were built based on measurements of cloud base altitude and integrated liquid water (ILW), all performed at the aerological station (MeteoSwiss) in Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the ILW was measured by a HATPRO (Humidity And Temperature PROfiler) radiometer. To assess the quality of the TEMPERA retrieval when clouds were considered, the resulting temperature profiles were compared to 2 years of radiosonde measurements. The TEMPERA instrument measures radiation at 12 channels in the frequency range from 51 to 57 GHz, corresponding to the left wing of the oxygen emission line complex. When the full spectral information with all the 12 frequency channels was used, we found a marked improvement in the temperature retrievals after including a cloud model. The chosen cloud model influenced the resulting temperature profile, especially for high clouds and clouds with a large amount of liquid water. Using all 12 channels, however, presented large deviations between different cases, suggesting that additional uncertainties exist in the lower, more transparent channels. Using less spectral information with the higher, more opaque channels only also improved the temperature profiles when clouds where included, but the influence of the chosen cloud model was less important. We conclude that tropospheric temperature profiles can be optimized by considering clouds in the microwave retrieval, and that the choice of the cloud model has a direct impact on the resulting temperature profile.

ACS Style

Leonie Bernet; Francisco Navas-Guzmán; Niklaus Kämpfer. The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements. Atmospheric Measurement Techniques 2017, 10, 4421 -4437.

AMA Style

Leonie Bernet, Francisco Navas-Guzmán, Niklaus Kämpfer. The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements. Atmospheric Measurement Techniques. 2017; 10 (11):4421-4437.

Chicago/Turabian Style

Leonie Bernet; Francisco Navas-Guzmán; Niklaus Kämpfer. 2017. "The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements." Atmospheric Measurement Techniques 10, no. 11: 4421-4437.

Journal article
Published: 25 October 2017 in Atmospheric Measurement Techniques
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Ground-based microwave radiometers (MWRs) offer the capability to provide continuous, high-temporal-resolution observations of the atmospheric thermodynamic state in the planetary boundary layer (PBL) with low maintenance. This makes MWR an ideal instrument to supplement radiosonde and satellite observations when initializing numerical weather prediction (NWP) models through data assimilation. State-of-the-art data assimilation systems (e.g. variational schemes) require an accurate representation of the differences between model (background) and observations, which are then weighted by their respective errors to provide the best analysis of the true atmospheric state. In this perspective, one source of information is contained in the statistics of the differences between observations and their background counterparts (O–B). Monitoring of O–B statistics is crucial to detect and remove systematic errors coming from the measurements, the observation operator, and/or the NWP model. This work illustrates a 1-year O–B analysis for MWR observations in clear-sky conditions for an European-wide network of six MWRs. Observations include MWR brightness temperatures (TB) measured by the two most common types of MWR instruments. Background profiles are extracted from the French convective-scale model AROME-France before being converted into TB. The observation operator used to map atmospheric profiles into TB is the fast radiative transfer model RTTOV-gb. It is shown that O–B monitoring can effectively detect instrument malfunctions. O–B statistics (bias, standard deviation, and root mean square) for water vapour channels (22.24–30.0 GHz) are quite consistent for all the instrumental sites, decreasing from the 22.24 GHz line centre ( ∼ 2–2.5 K) towards the high-frequency wing ( ∼ 0.8–1.3 K). Statistics for zenith and lower-elevation observations show a similar trend, though values increase with increasing air mass. O–B statistics for temperature channels show different behaviour for relatively transparent (51–53 GHz) and opaque channels (54–58 GHz). Opaque channels show lower uncertainties (< 0.8–0.9 K) and little variation with elevation angle. Transparent channels show larger biases ( ∼ 2–3 K) with relatively low standard deviations ( ∼ 1–1.5 K). The observations minus analysis TB statistics are similar to the O–B statistics, suggesting a possible improvement to be expected by assimilating MWR TB into NWP models. Lastly, the O–B TB differences have been evaluated to verify the normal-distribution hypothesis underlying variational and ensemble Kalman filter-based DA systems. Absolute values of excess kurtosis and skewness are generally within 1 and 0.5, respectively, for all instrumental sites, demonstrating O–B normal distribution for most of the channels and elevations angles.

ACS Style

Francesco De Angelis; Domenico Cimini; Ulrich Löhnert; Olivier Caumont; Alexander Haefele; Bernhard Pospichal; Pauline Martinet; Francisco Navas-Guzmán; Henk Klein-Baltink; Jean-Charles Dupont; James Hocking. Long-term observations minus background monitoring of ground-based brightness temperatures from a microwave radiometer network. Atmospheric Measurement Techniques 2017, 10, 3947 -3961.

AMA Style

Francesco De Angelis, Domenico Cimini, Ulrich Löhnert, Olivier Caumont, Alexander Haefele, Bernhard Pospichal, Pauline Martinet, Francisco Navas-Guzmán, Henk Klein-Baltink, Jean-Charles Dupont, James Hocking. Long-term observations minus background monitoring of ground-based brightness temperatures from a microwave radiometer network. Atmospheric Measurement Techniques. 2017; 10 (10):3947-3961.

Chicago/Turabian Style

Francesco De Angelis; Domenico Cimini; Ulrich Löhnert; Olivier Caumont; Alexander Haefele; Bernhard Pospichal; Pauline Martinet; Francisco Navas-Guzmán; Henk Klein-Baltink; Jean-Charles Dupont; James Hocking. 2017. "Long-term observations minus background monitoring of ground-based brightness temperatures from a microwave radiometer network." Atmospheric Measurement Techniques 10, no. 10: 3947-3961.

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Published: 16 October 2017
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ACS Style

Francisco Navas-Guzmán. Answers to referee 1. 2017, 1 .

AMA Style

Francisco Navas-Guzmán. Answers to referee 1. . 2017; ():1.

Chicago/Turabian Style

Francisco Navas-Guzmán. 2017. "Answers to referee 1." , no. : 1.

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Published: 16 October 2017
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ACS Style

Francisco Navas-Guzmán. Answer to referee 2. 2017, 1 .

AMA Style

Francisco Navas-Guzmán. Answer to referee 2. . 2017; ():1.

Chicago/Turabian Style

Francisco Navas-Guzmán. 2017. "Answer to referee 2." , no. : 1.