scholarly journals Australian Lidar Measurements of Aerosol Layers Associated with the 2015 Calbuco Eruption

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 124
Author(s):  
Andrew R. Klekociuk ◽  
David J. Ottaway ◽  
Andrew D. MacKinnon ◽  
Iain M. Reid ◽  
Liam V. Twigger ◽  
...  
Keyword(s):  
Vertical Motion ◽  
Stratospheric Aerosol ◽  
Spatial Inhomogeneity ◽  
Volcanic Plume ◽  
Orthogonal Polarization ◽  
Aerosol Layer ◽  
Lidar Measurements ◽  
The Mean ◽  
Volcanic Aerosols ◽  
Ground Based Lidar

The Calbuco volcano in southern Chile (41.3° S, 72.6° W) underwent three separate eruptions on 22–23 April 2015. Following the eruptions, distinct layers of enhanced lidar backscatter at 532 nm were observed in the lower stratosphere above Buckland Park, South Australia (34.6° S, 138.5° E), and Kingston, Tasmania (43.0° S, 147.3° E), during a small set of observations in April–May 2015. Using atmospheric trajectory modelling and measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) space-borne lidar and the Ozone Mapping Profiler Suite (OMPS) instrument on the Suomi National Polar-orbiting Partnership (NPP) satellite, we show that these layers were associated with the Calbuco eruptions. Buckland Park measurements on 30 April and 3 May detected discrete aerosol layers at and slightly above the tropopause, where the relative humidity was well below saturation. Stratospheric aerosol layers likely associated with the eruptions were observed at Kingston on 17 and 22 May in narrow discrete layers accompanied by weaker and more vertically extended backscatter. The measurements on 22 May provided a mean value of the particle linear depolarisation ratio within the main observed volcanic aerosol layer of 18.0 ± 3.0%, which was consistent with contemporaneous CALIOP measurements. The depolarisation measurements indicated that this layer consisted of a filament dominated by ash backscatter residing above a main region having likely more sulfate backscatter. Layer-average optical depths were estimated from the measurements. The mean lidar ratio for the volcanic aerosols on 22 May of 86 ± 37 sr is consistent with but generally higher than the mean for ground-based measurements for other volcanic events. The inferred optical depth for the main volcanic layer on 17 May was consistent with a value obtained from OMPS measurements, but a large difference on 22 May likely reflected the spatial inhomogeneity of the volcanic plume. Short-lived enhancements of backscatter near the tropopause of 17 May likely represented the formation cirrus that was aided by the presence of associated volcanic aerosols. We also provide evidence that gravity waves potentially influenced the layers, particularly in regard to the vertical motion observed in the strong layer on 22 May. Overall, these observations provide additional information on the dispersal and characteristics of the Calbuco aerosol plumes at higher southern latitudes than previously reported for ground-based lidar measurements.

scholarly journals Variability and evolution of the midlatitude stratospheric aerosol budget from 22 years of ground-based lidar and satellite observations

2017 ◽  
Vol 17 (3) ◽  
pp. 1829-1845 ◽  
Author(s):  
Sergey M. Khaykin ◽  
Sophie Godin-Beekmann ◽  
Philippe Keckhut ◽  
Alain Hauchecorne ◽  
Julien Jumelet ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Infrared Imaging ◽  
Imaging System ◽  
Late Summer ◽  
Stratospheric Aerosol ◽  
Atmospheric Composition ◽  
Orthogonal Polarization ◽  
Asian Monsoon Region ◽  
Lidar Measurements ◽  
Ground Based Lidar

Abstract. The article presents new high-quality continuous stratospheric aerosol observations spanning 1994–2015 at the French Observatoire de Haute-Provence (OHP, 44° N, 6° E) obtained by two independent, regularly maintained lidar systems operating within the Network for Detection of Atmospheric Composition Change (NDACC). Lidar series are compared with global-coverage observations by Stratospheric Aerosol and Gas Experiment (SAGE II), Global Ozone Monitoring by Occultation of Stars (GOMOS), Optical Spectrograph and InfraRed Imaging System (OSIRIS), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and Ozone Mapping Profiling Suite (OMPS) satellite instruments, altogether covering the time span of OHP lidar measurements. Local OHP and zonal-mean satellite series of stratospheric aerosol optical depth are in excellent agreement, allowing for accurate characterization of stratospheric aerosol evolution and variability at northern midlatitudes during the last 2 decades. The combination of local and global observations is used for a careful separation between volcanically perturbed and quiescent periods. While the volcanic signatures dominate the stratospheric aerosol record, the background aerosol abundance is found to be modulated remotely by the poleward transport of convectively cleansed air from the deep tropics and aerosol-laden air from the Asian monsoon region. The annual cycle of background aerosol at midlatitudes, featuring a minimum during late spring and a maximum during late summer, correlates with that of water vapor from the Aura Microwave Limb Sounder (MLS). Observations covering two volcanically quiescent periods over the last 2 decades provide an indication of a growth in the nonvolcanic component of stratospheric aerosol. A statistically significant factor of 2 increase in nonvolcanic aerosol since 1998, seasonally restricted to late summer and fall, is associated with the influence of the Asian monsoon and growing pollution therein.

scholarly journals Variability and evolution of mid-latitude stratospheric aerosol budget from 22 years of ground-based lidar and satellite observations

2016 ◽  
Author(s):  
Sergey M. Khaykin ◽  
Sophie Godin-Beekmann ◽  
Philippe Keckhut ◽  
Alain Hauchecorne ◽  
Julien Jumelet ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Infrared Imaging ◽  
Imaging System ◽  
Late Summer ◽  
Stratospheric Aerosol ◽  
Orthogonal Polarization ◽  
Asian Monsoon Region ◽  
Lidar Measurements ◽  
Global Coverage ◽  
Ground Based Lidar

Abstract. The article presents new high-quality continuous stratospheric aerosol observations spanning 1994–2015 at the French Observatoire de Haute-Provence (OHP, 44° N, 6° E) obtained by two independent regularly-maintained lidar systems. Lidar series are compared with global-coverage observations by Stratospheric Aerosol and Gas Experiment (SAGE II), Global Ozone Monitoring by Occultation of Stars (GOMOS), Optical Spectrograph and InfraRed Imaging System (OSIRIS), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Ozone Mapping Profiling Suite (OMPS) satellite instruments, altogether covering the time span of OHP lidar measurements. Local OHP and zonal-mean satellite series of stratospheric aerosol optical depth are in excellent agreement, allowing for accurate characterization of stratospheric aerosol evolution and variability at Northern mid-latitudes during the post-Pinatubo era. The combination of local and global observations is used for careful separation between volcanically-perturbed and quiescent periods. While the volcanic signatures dominate the stratospheric aerosol record, the background aerosol abundance is found to be modulated remotely by poleward transport of convectively-cleansed air from the deep tropics and aerosol-laden air from the Asian monsoon region. The annual cycle of background aerosol at mid-latitudes, featuring a minimum during late spring and a maximum during late summer, correlates with that of water vapour from Microwave Limb Sounder (MLS). Observations covering two volcanically-quiescent periods over the last two decades provide indication of a growth in the non-volcanic component of stratospheric aerosol. A statistically-significant factor of two increase of non-volcanic aerosol since 1998, seasonally restricted to late-summer and fall, is associated with the influence of the Asian monsoon and growing pollution therein.

scholarly journals Lidar observations of Nabro volcano aerosol layers in the stratosphere over Gwangju, Korea

2015 ◽  
Vol 15 (1) ◽  
pp. 1171-1191 ◽  
Author(s):  
D. Shin ◽  
D. Müller ◽  
K. Lee ◽  
S. Shin ◽  
Y. J. Kim ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Upper Troposphere ◽  
Lidar Measurements ◽  
Volcanic Aerosols ◽  
Lidar Observations ◽  
532 Nm

Abstract. We report on the first Raman lidar measurements of stratospheric aerosol layers in the upper troposphere and lower stratosphere over Korea. The data were taken with the multiwavelength aerosol Raman lidar at Gwangju (35.10° N, 126.53° E), Korea. The volcanic ash particles and gases were released around 12 June 2011 during the eruption of the Nabro volcano (13.37° N, 41.7° E) in Eritrea, east Africa. Forward trajectory computations show that the volcanic aerosols were advected from North Africa to East Asia. The first observation of the stratospheric aerosol layers over Korea was on 19 June 2011. The stratospheric aerosol layers appeared between 15 and 17 km height a.s.l. The aerosol layers' maximum value of the backscatter coefficient and the linear particle depolarization ratio at 532 nm were 1.5 ± 0.3 Mm−1 sr−1 and 2.2%, respectively. We found these values at 16.4 km height a.s.l. 44 days after this first observation, we observed the stratospheric aerosol layer again. We continuously probed the upper troposphere and lower stratosphere for this aerosol layer during the following 5 months, until December 2011. The aerosol layers typically occurred between 10 and 20 km height a.s.l. The stratospheric aerosol optical depth and the maximum backscatter coefficient at 532 nm decreased during these 5 months.

scholarly journals Enhancement of stratospheric aerosols after solar proton event

1996 ◽  
Vol 14 (11) ◽  
pp. 1119-1123 ◽  
Author(s):  
O. I. Shumilov ◽  
E. A. Kasatkina ◽  
K. Henriksen ◽  
E. V. Vashenyuk
Keyword(s):  
Considerable Increase ◽  
Ground Level ◽  
Solar Proton ◽  
Stratospheric Aerosol ◽  
Nucleation Mechanism ◽  
Solar Proton Event ◽  
Proton Event ◽  
Aerosol Layer ◽  
Event Type ◽  
Lidar Measurements

Abstract. The lidar measurements at Verhnetulomski observatory (68.6°N, 31.8°E) at Kola peninsula detected a considerable increase of stratospheric aerosol concentration after the solar proton event of GLE (ground level event) type on the 16/02/84. This increase was located at precisely the same altitude range where the energetic solar protons lost their energy in the atmosphere. The aerosol layer formed precipitated quickly (1–2 km per day) during 18, 19, and 20 February 1984, and the increase of R(H) (backscattering ratio) at 17 km altitude reached 40% on 20/02/84. We present the model calculation of CN (condensation nuclei) altitude distribution on the basis of an ion-nucleation mechanism, taking into account the experimental energy distribution of incident solar protons. The meteorological situation during the event was also investigated.

scholarly journals CALIPSO level 3 stratospheric aerosol profile product: version 1.00 algorithm description and initial assessment

2019 ◽  
Vol 12 (11) ◽  
pp. 6173-6191 ◽  
Author(s):  
Jayanta Kar ◽  
Kam-Pui Lee ◽  
Mark A. Vaughan ◽  
Jason L. Tackett ◽  
Charles R. Trepte ◽  
...  
Keyword(s):  
Space Station ◽  
Volcanic Eruptions ◽  
Satellite Observation ◽  
Stratospheric Aerosol ◽  
Initial Assessment ◽  
Orthogonal Polarization ◽  
Aerosol Layer ◽  
Stratospheric Dynamics ◽  
Level 3 ◽  
Lidar Ratio

Abstract. In August 2018, the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) project released a new level 3 stratospheric aerosol profile data product derived from nearly 12 years of measurements acquired by the spaceborne Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP). This monthly averaged, gridded level 3 product is based on version 4 of the CALIOP level 1B and level 2 data products, which feature significantly improved calibration that now makes it possible to reliably retrieve profiles of stratospheric aerosol extinction and backscatter coefficients at 532 nm. This paper describes the science algorithm and data handling techniques that were developed to generate the CALIPSO version 1.00 level 3 stratospheric aerosol profile product. Further, we show that the extinction profiles (retrieved using a constant lidar ratio of 50 sr) capture the major stratospheric perturbations in both hemispheres over the last decade resulting from volcanic eruptions, extreme smoke events, and signatures of stratospheric dynamics. Initial assessment of the product by intercomparison with the stratospheric aerosol retrievals from the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station (ISS) indicates good agreement in the tropical stratospheric aerosol layer (30∘ N–30∘ S), where the average difference between zonal mean extinction profiles is typically less than 25 % between 20 and 30 km (CALIPSO biased high). However, differences can exceed 100 % in the very low aerosol loading regimes found above 25 km at higher latitudes. Similarly, there are large differences (≥100 %) within 2 to 3 km above the tropopause that might be due to cloud contamination issues.

scholarly journals Year-round stratospheric aerosol backscatter ratios calculated from lidar measurements above northern Norway

2019 ◽  
Vol 12 (7) ◽  
pp. 4065-4076 ◽  
Author(s):  
Arvid Langenbach ◽  
Gerd Baumgarten ◽  
Jens Fiedler ◽  
Franz-Josef Lübken ◽  
Christian von Savigny ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Stratospheric Aerosol ◽  
New Method ◽  
The Arctic ◽  
Correction Function ◽  
Aerosol Layer ◽  
Radiative Balance ◽  
Northern Norway ◽  
Lidar Measurements ◽  
Aerosol Backscatter

Abstract. We present a new method for calculating backscatter ratios of the stratospheric sulfate aerosol (SSA) layer from daytime and nighttime lidar measurements. Using this new method we show a first year-round dataset of stratospheric aerosol backscatter ratios at high latitudes. The SSA layer is located at altitudes between the tropopause and about 30 km. It is of fundamental importance for the radiative balance of the atmosphere. We use a state-of-the-art Rayleigh–Mie–Raman lidar at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) station located in northern Norway (69∘ N, 16∘ E; 380 m a.s.l.). For nighttime measurements the aerosol backscatter ratios are derived using elastic and inelastic backscatter of the emitted laser wavelengths 355, 532 and 1064 nm. The setup of the lidar allows measurements with a resolution of about 5 min in time and 150 m in altitude to be performed in high quality, which enables the identification of multiple sub-layers in the stratospheric aerosol layer of less than 1 km vertical thickness. We introduce a method to extend the dataset throughout the summer when measurements need to be performed under permanent daytime conditions. For that purpose we approximate the backscatter ratios from color ratios of elastic scattering and apply a correction function. We calculate the correction function using the average backscatter ratio profile at 355 nm from about 1700 h of nighttime measurements from the years 2000 to 2018. Using the new method we finally present a year-round dataset based on about 4100 h of measurements during the years 2014 to 2017.

scholarly journals 35 yr of stratospheric aerosol measurements at Garmisch-Partenkirchen: from Fuego to Eyjafjallajökull, and beyond

2013 ◽  
Vol 13 (10) ◽  
pp. 5205-5225 ◽  
Author(s):  
T. Trickl ◽  
H. Giehl ◽  
H. Jäger ◽  
H. Vogelmann
Keyword(s):  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Saharan Dust ◽  
Positive Trend ◽  
Aerosol Layer ◽  
Mauna Loa ◽  
Background Period ◽  
Lidar Measurements ◽  
Tropopause Region ◽  
Volcanic Impact

Abstract. Lidar measurements at Garmisch-Partenkirchen (Germany) have almost continually delivered backscatter coefficients of stratospheric aerosol since 1976. The time series is dominated by signals from the particles injected into or formed in the stratosphere due to major volcanic eruptions, in particular those of El Chichon (Mexico, 1982) and Mt Pinatubo (Philippines, 1991). Here, we focus more on the long-lasting background period since the late 1990s and 2006, in view of processes maintaining a residual lower-stratospheric aerosol layer in absence of major eruptions, as well as the period of moderate volcanic impact afterwards. During the long background period the stratospheric backscatter coefficients reached a level even below that observed in the late 1970s. This suggests that the predicted potential influence of the strongly growing air traffic on the stratospheric aerosol loading is very low. Some correlation may be found with single strong forest-fire events, but the average influence of biomass burning seems to be quite limited. No positive trend in background aerosol can be resolved over a period as long as that observed by lidar at Mauna Loa. We conclude that the increase of our integrated backscatter coefficients starting in 2008 is mostly due to volcanic eruptions with explosivity index 4, penetrating strongly into the stratosphere. Most of them occurred in the mid-latitudes. A key observation for judging the role of eruptions just reaching the tropopause region was that of the plume from the Icelandic volcano Eyjafjallajökull above Garmisch-Partenkirchen (April 2010) due to the proximity of that source. The top altitude of the ash above the volcano was reported just as 9.3 km, but the lidar measurements revealed enhanced stratospheric aerosol up to 14.3 km. Our analysis suggests for two or three of the four measurement days the presence of a stratospheric contribution from Iceland related to quasi-horizontal transport, differing from the strong descent of the layers entering Central Europe at low altitudes. The backscatter coefficients within the first 2 km above the tropopause exceed the stratospheric background by a factor of four to five. In addition, Asian and Saharan dust layers were identified in the free troposphere, Asian dust most likely even in the stratosphere.

scholarly journals Year-round stratospheric aerosol backscatter ratios calculated from lidar measurements above Northern Norway

2019 ◽  
Author(s):  
Arvid Brand ◽  
Gerd Baumgarten ◽  
Jens Fiedler ◽  
Franz-Josef Lübken ◽  
Christian von Savigny ◽  
...  
Keyword(s):  
Scattered Light ◽  
Stratospheric Aerosol ◽  
Research Station ◽  
Aerosol Layer ◽  
Radiative Balance ◽  
Northern Norway ◽  
Spatial And Temporal Scales ◽  
Microphysical Properties ◽  
Lidar Measurements ◽  
Aerosol Backscatter

Abstract. In this work, the processing of a year-round stratospheric sulphate aerosol (SSA) dataset from day- and nighttime lidar measurements is presented. The SSA layer is of fundamental importance for the radiative balance of the atmosphere. The layer is found at altitudes between the tropopause and about 30 km. We use a state of the art Doppler Rayleigh-Mie-Raman lidar at the ALOMAR research station located in Northern Norway (69° N, 16° E) to observe the aerosol layer and derive microphysical properties. The lidar allows the investigation of SSA from small spatial and temporal scales to decadal variations. The aerosol backscatter ratio is derived by using a multi-wavelength approach and different scattering processes. Here we introduce a method for the extension of the dataset throughout the summer where measurements have to be performed under permanent daytime conditions. We calculate backscatter ratios from color ratios of elastic scattered light at the wavelengths 355, 532 and 1064 nm. These color ratios are corrected using an average backscatter ratio profile at 355 nm from the years 2000 to 2018. Thereby, we are able to extend the dataset from 2883 hours of nighttime data to 7273 hours of total data time between 2000 and 2018.

scholarly journals Validation of CALIPSO space-borne-derived aerosol vertical structures using a ground-based lidar in Athens, Greece

2009 ◽  
Vol 2 (1) ◽  
pp. 561-587 ◽  
Author(s):  
R. E. Mamouri ◽  
V. Amiridis ◽  
A. Papayannis ◽  
E. Giannakaki ◽  
G. Tsaknakis ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Air Masses ◽  
Continental Scale ◽  
Comparison Results ◽  
Tropospheric Aerosol ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
The Mean ◽  
Ground Based Lidar ◽  
Signal Attenuations

Abstract. We present initial aerosol validation results of the space-borne lidar CALIOP retrievals -onboard the CALIPSO satellite-, using coincident observations performed with a ground-based lidar in Athens, Greece (37.9° N, 23.6° E). A multi-wavelength ground-based backscatter/Raman lidar system is operating since 2000 at the National Technical University of Athens (NTUA) in the framework of the European Aerosol Research LIdar NETwork (EARLINET), the first lidar network for tropospheric aerosol studies on a continental scale. Since July 2006, a total of 40 coincidental aerosol ground-based lidar measurements were performed over Athens during CALIPSO overpasses. The duration of the ground-based lidar measurements was approximately two hours, centred on the satellite overpass time. From the statistical analysis of the ground-based/satellite correlative lidar measurements, a mean bias of the order of 22% for daytime measurements and of 8% for nighttime measurements with respect to the CALIPSO profiles was found for altitudes between 3 and 10 km. The mean bias becomes much larger for altitudes lower that 3 km (of the order of 60%) which is attributed to the decrease of the CALIOP signal-to-noise ratio, as well as to the incomplete overlap height region of the ground based lidar and finally to the distance between the two instruments, resulting to the observation of possibly different air masses. In cases of aerosols layers underlying cirrus clouds, comparison results for aerosol tropospheric profiles become worst, illustrating the limitations of space-borne downward-looking lidar measurements due to strong signal attenuations.

scholarly journals Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations

2011 ◽  
Vol 11 (11) ◽  
pp. 29681-29721 ◽  
Author(s):  
M. Sicard ◽  
J. L. Guerrero-Rascado ◽  
F. Navas-Guzmán ◽  
J. Preißler ◽  
F. Molero ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Mass Concentration ◽  
Temporal Evolution ◽  
Volcanic Plume ◽  
Volcanic Aerosol ◽  
The Mean ◽  
Sun Photometer ◽  
Volcanic Aerosols ◽  
First Time ◽  
Aerosol Plume

Abstract. Lidar and sun-photometer measurements were performed intensively over the Iberian Peninsula (IP) during the eruption of Eyjafjallajökull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (<1000 m) with a top height up to 11–12 km. The mean optical thicknesses associated to those layers were rather low (between 0.013 and 0.020 over the whole period). Punctually on 7 May the optical thickness reached peak values near 0.10. Secondly the volcanic aerosols are characterized in terms of extinction and backscatter coefficients, lidar ratios, Ångström exponents and linear particle depolarization ratio. Lidar ratios at different sites varied between 30 and 50 sr without a marked spectral dependency. Similar extinction-related Ångström exponents varying between 0.6 and 0.8 were observed at different sites. The temporal evolution of the backscatter-related Ångström exponents points out a possible decrease of the volcanic particle size as the plume moves from west to east. Particle depolarization ratios on the order of 0.06–0.08 confirmed the coexistence of both ash and non-ash particles. Additionally profiles of mass concentration were obtained with a method using the opposite depolarizing effects of ash particles (strongly depolarizing) and non-ash particles (very weakly depolarizing), and sun-photometer observations. In Granada the ash mass concentration was found approximately 1.5 higher than that of non-ash particles, and probably did not exceed the value of 200 μg m−3 during the whole event.

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