scholarly journals Measurement Report: Lidar measurements of stratospheric aerosol following the Raikoke and Ulawun volcanic eruptions

2020 ◽  
Author(s):  
Geraint Vaughan ◽  
David Wareing ◽  
Hugo Ricketts
Keyword(s):  
Volcanic Ash ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Lidar System ◽  
Elastic Channel ◽  
Lidar Measurements ◽  
Volcanic Cloud ◽  
Lidar Ratio

Abstract. On 22 June 2019 the Raikoke volcano in the Kuril islands erupted, sending a plume of ash and sulphur dioxide into the stratosphere. A Raman lidar system at Capel Dewi Atmospheric Observatory, UK (52.4° N, 4.1° W) has been used to measure the extent and optical depth of the stratospheric aerosol layer following the eruption. The elastic channel allowed measurements up to 25 km, but the Raman channel was only sensitive to the troposphere. Therefore, backscatter ratio profiles were derived by comparison with aerosol-free profiles derived from nearby radiosondes, corrected for aerosol extinction with a lidar ratio of 40–50 sr. Small amounts of aerosol were measured prior to the arrival of the volcanic cloud, probably from pyroconvection over Canada. Volcanic ash may have first arrived as a thin layer at 14 km late on 3 July, and was certainly detected from 13 July onwards, eventually extending up to 20.5 km. Aerosol optical depths reached around 0.05 by early August, decaying thereafter to around 0.01 by the end of 2019 and remaining around that level until May 2020. The location of peak backscatter varied considerably but was generally around 15 km. However, on one notable occasion on 25 August, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.

Lidar observations of volcanic aerosol over the UK since June 2019

2020 ◽  
Author(s):  
Geraint Vaughan ◽  
David Wareing ◽  
Hugo Ricketts
Keyword(s):  
Volcanic Ash ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Lidar System ◽  
Elastic Channel ◽  
Enhanced Sensitivity ◽  
Volcanic Cloud ◽  
The Uk ◽  
Lidar Observations

<p>On 22 June 2019, the Raikoke volcano in the Kuril Islands erupted, sending a plume of ask and sulphur dioxide into the stratosphere. A Raman lidar system at Capel Dewi, UK (52.4°N, 4.1°W) has been used to measure the extent and optical depth of the stratospheric aerosol layer following the eruption. The lidar was modified to give it much enhanced sensitivity in the elastic channel, allowing measurements up to 25 km, but the Raman channel is only sensitive to the troposphere. Therefore, backscatter ratio profiles were derived by comparison with aerosol-free profiles derived from nearby radiosondes, corrected for aerosol extinction. Small amounts of stratospheric aerosol were measured prior to the arrival of the volcanic cloud, probably from pyroconvection over Canada. Volcanic ash began to arrive as a thin layer at 14 km late on 3 July, extending over the following month to fill the stratosphere below around 19 km. Aerosol optical depths reached around 0.03 by mid-August and continued at this level for the remainder of the year. The location of peak backscatter varied considerably but was generally around 15 km. However, on one notable occasion on August 25, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.</p>

scholarly journals Measurement Report: Lidar measurements of stratospheric aerosol following the 2019 Raikoke and Ulawun volcanic eruptions

2021 ◽  
Vol 21 (7) ◽  
pp. 5597-5604
Author(s):  
Geraint Vaughan ◽  
David Wareing ◽  
Hugo Ricketts
Keyword(s):  
Initial Period ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Elastic Channel ◽  
Aerosol Cloud ◽  
Maximum Value ◽  
Lidar Measurements ◽  
Volcanic Cloud ◽  
Lidar Ratio ◽  
The Uk

Abstract. At 18:00 UTC on 21 June 2019 the Raikoke volcano in the Kuril islands began a large-magnitude explosive eruption, sending a plume of ash and sulfur dioxide into the stratosphere. A Raman lidar system at Capel Dewi Atmospheric Observatory, UK, was deployed to measure the vertical extent and optical depth of the volcanic aerosol cloud following the eruption. The elastic channel at 355 nm allowed measurements up to 25 km, but the Raman channel was only sensitive to the troposphere. Therefore, retrievals of backscatter ratio profiles from the raw backscatter measurements required aerosol-free profiles derived from nearby radiosondes and allowance for aerosol extinction using a lidar ratio of 40–50 sr. Small amounts of aerosol were measured prior to the arrival of the volcanic cloud (27 June–5 July 2019), from pyroconvection over Canada. Model simulations by de Leeuw et al. (2020) and Kloss et al. (2020) show that volcanic ash may have reached Europe from 1 July onwards and was certainly present over the UK after 10 July. The lidar detected a thin layer at an altitude of 14 km late on 3 July, with the first detection of the main aerosol cloud on 13 July. In this initial period the aerosol was confined below 16 km, but eventually the cloud extended to 20.5 km. A sustained period of clearly enhanced stratospheric aerosol optical depths began in early August, with a maximum value (at 355 nm) around 0.05 in mid-August and remaining above 0.02 until early November. Thereafter, optical depths decayed to around 0.01 by the end of 2019 and remained around that level until May 2020. The altitude of peak backscatter varied considerably (between 14 and 18 km) but was generally around 15 km. However, on one notable occasion on 25 August 2019, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.

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

2012 ◽  
Vol 12 (9) ◽  
pp. 23135-23193 ◽  
Author(s):  
T. Trickl ◽  
H. Giehl ◽  
H. Jäger ◽  
H. Vogelmann
Keyword(s):  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Saharan Dust ◽  
Positive Trend ◽  
Aerosol Layer ◽  
Quasi Biennial Oscillation ◽  
Mauna Loa ◽  
Background Period ◽  
Lidar Measurements ◽  
Volcanic Impact

Abstract. The powerful backscatter lidar at Garmisch-Partenkirchen (Germany) has almost continually delivered backscatter coefficients of the 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). The volcanic aerosol disappears within about five years, the removal from the stratosphere being modulated by the phase of the quasi-biennial oscillation. 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 or Boulder. This suggests being careful with invoking Asian air pollution as the main source as found in the literature. Rather an impact of previously missed volcanic eruptions on the stratospheric aerosol must be taken into consideration. A key observation in this regard 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 next to the source was reported just as roughly 9.3 km, but the lidar measurements revealed enhanced stratospheric aerosol up to 14.5 km. Our analysis suggests for two, perhaps three, of the four measurement days the presence of a stratospheric contribution from Iceland related to quasi-horizontal transport, contrasting the strongly descending lower layers entering Central Europe. The backscatter coefficients within the first 2 km above the tropopause exceed the stratospheric background by a factor of three to four. In addition, Asian and Saharan dust layers were identified in the free troposphere, Asian dust most likely even in the stratosphere. The number of minor mid-latitude eruptions has gradually increased during the past ten years. We conclude that, although their stratospheric contribution could not be clearly identified above our site they can sum up for forming some minor background. Clear stratospheric signatures were only seen in the case of eruptions reaching higher altitudes.

scholarly journals 30-year lidar observations of the stratospheric aerosol layer state over Tomsk (Western Siberia, Russia)

2017 ◽  
Vol 17 (4) ◽  
pp. 3067-3081 ◽  
Author(s):  
Vladimir V. Zuev ◽  
Vladimir D. Burlakov ◽  
Aleksei V. Nevzorov ◽  
Vladimir L. Pravdin ◽  
Ekaterina S. Savelieva ◽  
...  
Keyword(s):  
Forest Fires ◽  
Western Siberia ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Background Period ◽  
Lidar Measurements ◽  
Soufriere Hills ◽  
Global Volcanism ◽  
Langley Research Center

Abstract. There are only four lidar stations in the world which have almost continuously performed observations of the stratospheric aerosol layer (SAL) state over the last 30 years. The longest time series of the SAL lidar measurements have been accumulated at the Mauna Loa Observatory (Hawaii) since 1973, the NASA Langley Research Center (Hampton, Virginia) since 1974, and Garmisch-Partenkirchen (Germany) since 1976. The fourth lidar station we present started to perform routine observations of the SAL parameters in Tomsk (56.48° N, 85.05° E, Western Siberia, Russia) in 1986. In this paper, we mainly focus on and discuss the stratospheric background period from 2000 to 2005 and the causes of the SAL perturbations over Tomsk in the 2006–2015 period. During the last decade, volcanic aerosol plumes from tropical Mt. Manam, Soufrière Hills, Rabaul, Merapi, Nabro, and Kelut and extratropical (northern) Mt. Okmok, Kasatochi, Redoubt, Sarychev Peak, Eyjafjallajökull, and Grímsvötn were detected in the stratosphere over Tomsk. When it was possible, we used the NOAA HYSPLIT trajectory model to assign aerosol layers observed over Tomsk to the corresponding volcanic eruptions. The trajectory analysis highlighted some surprising results. For example, in the cases of the Okmok, Kasatochi, and Eyjafjallajökull eruptions, the HYSPLIT air mass backward trajectories, started from altitudes of aerosol layers detected over Tomsk with a lidar, passed over these volcanoes on their eruption days at altitudes higher than the maximum plume altitudes given by the Smithsonian Institution Global Volcanism Program. An explanation of these facts is suggested. The role of both tropical and northern volcanic eruptions in volcanogenic aerosol loading of the midlatitude stratosphere is also discussed. In addition to volcanoes, we considered other possible causes of the SAL perturbations over Tomsk, i.e., the polar stratospheric cloud (PSC) events and smoke plumes from strong forest fires. At least two PSC events were detected in 1995 and 2007. We also make an assumption that the Kelut volcanic eruption (Indonesia, February 2014) could be the cause of the SAL perturbations over Tomsk during the first quarter of 2015.

scholarly journals Technical Note: One year of Raman-lidar measurements in Gual Pahari EUCAARI site close to New Delhi in India – Seasonal characteristics of the aerosol vertical structure

2012 ◽  
Vol 12 (10) ◽  
pp. 4513-4524 ◽  
Author(s):  
M. Komppula ◽  
T. Mielonen ◽  
A. Arola ◽  
K. Korhonen ◽  
H. Lihavainen ◽  
...  
Keyword(s):  
Technical Note ◽  
New Delhi ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Extinction Coefficients ◽  
Seasonal Characteristics ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
One Year

Abstract. One year of multi-wavelength (3 backscatter + 2 extinction + 1 depolarization) Raman lidar measurements at Gual Pahari, close to New Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscatter, extinction, and lidar ratio and their variability during each season are presented. The measurements revealed that, on average, the aerosol layer was at its highest in spring (5.5 km). In summer, the vertically averaged (between 1–3 km) backscatter and extinction coefficients had the highest averages (3.3 Mm−1 sr−1 and 142 Mm−1 at 532 nm, respectively). Aerosol concentrations were slightly higher in summer compared to other seasons, and particles were larger in size. The autumn showed the highest lidar ratio and high extinction-related Ångström exponents (AEext), indicating the presence of smaller probably absorbing particles. The winter had the lowest backscatter and extinction coefficients, but AEext was the highest, suggesting still a large amount of small particles.

scholarly journals One year of Raman-lidar measurements in Gual Pahari EUCAARI site close to New Delhi in India: seasonal characteristics of the aerosol vertical structure

2010 ◽  
Vol 10 (12) ◽  
pp. 31123-31151 ◽  
Author(s):  
M. Komppula ◽  
T. Mielonen ◽  
A. Arola ◽  
K. Korhonen ◽  
H. Lihavainen ◽  
...  
Keyword(s):  
New Delhi ◽  
Aerosol Layer ◽  
Raman Lidar ◽  
Extinction Coefficients ◽  
Seasonal Characteristics ◽  
Four Seasons ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
One Year

Abstract. One year of multi-wavelength (3+2) Raman lidar measurements at Gual Pahari, close to Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscatter, extinction, and lidar ratio and their variability during each season are presented. The measurements revealed that, on average, the aerosol layer was at its highest in spring (5.5 km). In summer, the vertically averaged (between 1–3 km) backscatter and extinction coefficients had the highest averages (3.3 Mm−1 sr−1 and 142 Mm−1 at 532 nm, respectively). Aerosol concentrations were slightly higher in summer compared with other seasons, and particles were larger in size. The autumn showed the highest lidar ratio and high extinction-related Ångström exponents (AEext), indicating the presence of smaller probably absorbing particles. The winter had the lowest backscatter and extinction coefficients, but AEext was the highest, suggesting still a large amount of small particles.

scholarly journals Lidar Observations of Aerosol Disturbances of the Stratosphere over Tomsk (56.5∘N;85.0∘E) in Volcanic Activity Period 2006–2011

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Oleg E. Bazhenov ◽  
Vladimir D. Burlakov ◽  
Sergey I. Dolgii ◽  
Aleksey V. Nevzorov
Keyword(s):  
Volcanic Activity ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Optical Characteristics ◽  
Activity Period ◽  
Aerosol Layer ◽  
Lidar Measurements ◽  
The Vertical Distribution ◽  
Sarychev Peak

The lidar measurements (Tomsk:56.5∘N;85.0∘E) of the optical characteristics of the stratospheric aerosol layer (SAL) in the volcanic activity period 2006–2011 are summarized and analyzed. The background SAL state with minimum aerosol content, observed since 1997 under the conditions of long-term volcanically quiet period, was interrupted in October 2006 by series of explosive eruptions of volcanoes of Pacific Ring of Fire: Rabaul (October 2006, New Guinea); Okmok and Kasatochi (July-August 2008, Aleutian Islands); Redoubt (March-April 2009, Alaska); Sarychev Peak (June 2009, Kuril Islands); Grimsvötn (May 2011, Iceland). A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions. Trends of variations in the total ozone content are also considered.

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.

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