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 Pure rotational-Raman channels of the Esrange lidar for temperature and particle extinction measurements in the troposphere and lower stratosphere

2013 ◽  
Vol 6 (1) ◽  
pp. 91-98 ◽  
Author(s):  
P. Achtert ◽  
M. Khaplanov ◽  
F. Khosrawi ◽  
J. Gumbel
Keyword(s):  
Lower Stratosphere ◽  
Thermal Structure ◽  
Atmospheric Temperature ◽  
Temperature Measurements ◽  
Integration Time ◽  
Aerosol Extinction ◽  
Temperature Profiles ◽  
Backscatter Coefficient ◽  
Upper Troposphere ◽  
532 Nm

Abstract. The Department of Meteorology at Stockholm University operates the Esrange Rayleigh/Raman lidar at Esrange (68° N, 21° E) near the Swedish city of Kiruna. This paper describes the design and first measurements of the new pure rotational-Raman channel of the Esrange lidar. The Esrange lidar uses a pulsed Nd:YAG solid-state laser operating at 532 nm as light source with a repetition rate of 20 Hz and a pulse energy of 350 mJ. The minimum vertical resolution is 150 m and the integration time for one profile is 5000 shots. The newly implemented channel allows for measurements of atmospheric temperature at altitudes below 35 km and is currently optimized for temperature measurements between 180 and 200 K. This corresponds to conditions in the lower Arctic stratosphere during winter. In addition to the temperature measurements, the aerosol extinction coefficient and the aerosol backscatter coefficient at 532 nm can be measured independently. Our filter-based design minimizes the systematic error in the obtained temperature profile to less than 0.51 K. By combining rotational-Raman measurements (5–35 km height) and the integration technique (30–80 km height), the Esrange lidar is now capable of measuring atmospheric temperature profiles from the upper troposphere up to the mesosphere. With the improved setup, the system can be used to validate current lidar-based polar stratospheric cloud classification schemes. The new capability of the instrument measuring temperature and aerosol extinction furthermore enables studies of the thermal structure and variability of the upper troposphere/lower stratosphere. Although several lidars are operated at polar latitudes, there are few instruments that are capable of measuring temperature profiles in the troposphere, stratosphere, and mesosphere, as well as aerosols extinction in the troposphere and lower stratosphere with daylight capability.

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 Lower-stratospheric aerosol measurements in eastward shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018

2020 ◽  
Author(s):  
Masatomo Fujiwara ◽  
Tetsu Sakai ◽  
Koichi Shiraishi ◽  
Yoichi Inai ◽  
Sergey Khaykin ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Forest Fires ◽  
Lower Stratosphere ◽  
Asian Summer Monsoon ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Upper Troposphere ◽  
Asian Summer ◽  
The Japanese Archipelago

Abstract. Eastward airmass transport from the Asian summer monsoon (ASM) anticyclone in the upper troposphere and lower stratosphere (UTLS) often involves eastward shedding vortices, which can cover most of the Japanese archipelago. We investigated the aerosol characteristics of these vortices by analysing data from two lidar systems in Japan, at Tsukuba (36.1° N, 140.1° E) and Fukuoka (33.55° N, 130.36° E), during the summer of 2018. We observed several events with enhanced particle signals at Tsukuba at 15.5–18 km altitude (at or above the local tropopause) during August–September 2018, with a backscattering ratio of ~1.10 and particle depolarization of ~5 % (i.e., not spherical, but more spherical than ice crystals). These particle characteristics may be consistent with those of solid aerosol particles, such as ammonium nitrate. Each event had a timescale of a few days. During the same study period, we also observed similar enhanced particle signals in the lower stratosphere at Fukuoka. The upper troposphere is often covered by cirrus clouds at both lidar sites. Backward trajectory calculations for these sites for days with enhanced particle signals in the lower stratosphere and days without indicate that the former airmasses originated within the ASM anticyclone, and the latter more from edge regions. Reanalysis carbon-monoxide and satellite water-vapour data indicate that eastward shedding vortices were involved in the observed aerosol enhancements. Satellite aerosol data confirm that the period and latitudinal region were free from the direct influence of documented volcanic eruptions and high latitude forest fires. Our results indicate that the Asian Tropopause Aerosol Layer (ATAL) over the ASM region extends east towards Japan in association with the eastward shedding vortices, and that lidar systems in Japan can detect at least the lower stratospheric portion of the ATAL during periods when the lower stratosphere is undisturbed by volcanic eruptions and forest fires. The upper tropospheric portion of the ATAL is either depleted by tropospheric processes (convection and wet scavenging) during eastward transport or is obscured by much stronger cirrus cloud signals.

scholarly journals Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018

2021 ◽  
Vol 21 (4) ◽  
pp. 3073-3090
Author(s):  
Masatomo Fujiwara ◽  
Tetsu Sakai ◽  
Tomohiro Nagai ◽  
Koichi Shiraishi ◽  
Yoichi Inai ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Forest Fires ◽  
Lower Stratosphere ◽  
Asian Summer Monsoon ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Layer ◽  
Upper Troposphere ◽  
Asian Summer ◽  
The Japanese Archipelago

Abstract. Eastward air-mass transport from the Asian summer monsoon (ASM) anticyclone in the upper troposphere and lower stratosphere (UTLS) often involves eastward-shedding vortices, which can cover most of the Japanese archipelago. We investigated the aerosol characteristics of these vortices by analysing data from two lidar systems in Japan, at Tsukuba (36.1∘ N, 140.1∘ E) and Fukuoka (33.55∘ N, 130.36∘ E), during the summer of 2018. We observed several events with enhanced particle signals at Tsukuba at 15.5–18 km of altitude (at or above the local tropopause) during August–September 2018, with a backscattering ratio of ∼ 1.10 and particle depolarization of ∼ 5 % (i.e. not spherical, but more spherical than ice crystals). These particle characteristics may be consistent with those of solid aerosol particles, such as ammonium nitrate. Each event had a timescale of a few days. During the same study period, we also observed similar enhanced particle signals in the lower stratosphere at Fukuoka. The upper troposphere is often covered by cirrus clouds at both lidar sites. Backward trajectory calculations for these sites for days with enhanced particle signals in the lower stratosphere and days without indicate that the former air masses originated within the ASM anticyclone and the latter more from edge regions. Reanalysis carbon monoxide and satellite water vapour data indicate that eastward-shedding vortices were involved in the observed aerosol enhancements. Satellite aerosol data confirm that the period and latitudinal region were free from the direct influence of documented volcanic eruptions and high-latitude forest fires. Our results indicate that the Asian tropopause aerosol layer (ATAL) over the ASM region extends east towards Japan in association with the eastward-shedding vortices and that lidar systems in Japan can detect at least the lower-stratospheric portion of the ATAL during periods when the lower stratosphere is undisturbed by volcanic eruptions and forest fires. The upper-tropospheric portion of the ATAL is either depleted by tropospheric processes (convection and wet scavenging) during eastward transport or is obscured by much stronger cirrus cloud signals.

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 Ground-based water vapor raman lidar measurements up to the upper troposphere and lower stratosphere for long-term monitoring

2012 ◽  
Vol 5 (1) ◽  
pp. 17-36 ◽  
Author(s):  
T. Leblanc ◽  
I. S. McDermid ◽  
T. D. Walsh
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Lower Troposphere ◽  
Atmospheric Composition ◽  
Raman Lidar ◽  
Upper Troposphere ◽  
Lidar Measurements ◽  
Development Data ◽  
Instrumental Development

Abstract. Recognizing the importance of water vapor in the upper troposphere and lower stratosphere (UTLS) and the scarcity of high-quality, long-term measurements, JPL began the development of a powerful Raman lidar in 2005 to try to meet these needs. This development was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review the stages in the instrumental development, data acquisition and analysis, profile retrieval and calibration procedures of the lidar, as well as selected results from three validation campaigns: MOHAVE (Measurements of Humidity in the Atmosphere and Validation Experiments), MOHAVE-II, and MOHAVE 2009. In particular, one critical result from this latest campaign is the very good agreement (well below the reported uncertainties) observed between the lidar and the Cryogenic Frost-Point Hygrometer in the entire lidar range 3–20 km, with a mean bias not exceeding 2% (lidar dry) in the lower troposphere, and 3% (lidar moist) in the UTLS. Ultimately the lidar has demonstrated capability to measure water vapor profiles from ∼1 km above the ground to the lower stratosphere with a precision of 10% or better near 13 km and below, and an estimated accuracy of 5%. Since 2005, nearly 1000 profiles have been routinely measured, and since 2009, the profiles have typically reached 14 km for one-hour integration times and 1.5 km vertical resolution, and can reach 21 km for 6-h integration times using degraded vertical resolutions. These performance figures show that, with our present target of routinely running our lidar two hours per night, 4 nights per week, we can achieve measurements with a precision in the UTLS equivalent to that achieved if launching one CFH per month.

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.

scholarly journals Ground-based water vapor Raman lidar measurements up to the upper troposphere and lower stratosphere – Part 1: Instrument development, optimization, and validation

2011 ◽  
Vol 4 (4) ◽  
pp. 5079-5109 ◽  
Author(s):  
I. S. McDermid ◽  
T. Leblanc ◽  
T. D. Walsh
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Companion Paper ◽  
Atmospheric Composition ◽  
Raman Lidar ◽  
Upper Troposphere ◽  
Lidar Measurements ◽  
Instrumental Development ◽  
Validation Experiments

Abstract. Recognizing the importance of water vapor in the upper troposphere and lower stratosphere (UT/LS) and the scarcity of high-quality, long-term measurements, JPL began the development of a powerful Raman lidar in 2005 to try to meet these needs. This development was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review the stages in the instrumental development of the lidar and the conclusions from three validation campaigns: MOHAVE, MOHAVE-II, and MOHAVE 2009 (Measurements of Humidity in the Atmosphere and Validation Experiments). The data analysis, profile retrieval and calibration procedures, as well as additional results from MOHAVE-2009 are presented in detail in a companion paper (Leblanc et al., 2011a). Ultimately the lidar has demonstrated capability to measure water vapor profiles from ~1 km above the ground to the lower stratosphere, reaching 14 km for 1-h integrated profiles and 21 km for 6-h integrated profiles, with a precision of 10 % or better near 13 km and below, and an estimated accuracy of 5 %.

scholarly journals Fluorescence lidar observations of wildfire smoke inside cirrus: A contribution to smoke-cirrus – interaction research

2021 ◽  
Author(s):  
Igor Veselovskii ◽  
Qiaoyun Hu ◽  
Albert Ansmann ◽  
Philippe Goloub ◽  
Thierry Podvin ◽  
...  
Keyword(s):  
Surface Area ◽  
Ice Crystal ◽  
Raman Lidar ◽  
Upper Troposphere ◽  
Wildfire Smoke ◽  
Microphysical Properties ◽  
Lidar Measurements ◽  
Lidar Observations ◽  
Interaction Research ◽  
Area And Volume

Abstract. A remote sensing method, based on fluorescence lidar measurements, that allows to detect and to quantify the smoke content in upper troposphere and lower stratosphere (UTLS) is presented. The unique point of this approach is that, smoke and cirrus properties are observed in the same air volume simultaneously. In the article, we provide results of fluorescence and multiwavelength Mie-Raman lidar measurements performed at ATOLL observatory from Laboratoire d’Optique Atmosphérique, University of Lille, during strong smoke episodes in the summer and autumn seasons of 2020. The aerosol fluorescence was induced by 355 nm laser radiation and the fluorescence backscattering was measured in a single spectral channel, centered at 466 nm of 44 nm width. To estimate smoke properties, such as number, surface area and volume concentration, the conversion factors, which link the fluorescence backscattering and the smoke microphysical properties, are derived from the synergy of multiwavelength Mie-Raman and fluorescence lidar observations. Based on two case studies, we demonstrate that the fluorescence lidar technique provides possibility to estimate the smoke surface area concentration within freshly formed cirrus layers. This value was used in smoke INP parameterization scheme to predict ice crystal number concentrations in cirrus generation cells.

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