scholarly journals Comparison of Coincident Optical Particle Counter and Lidar Measurements of Polar Stratospheric Clouds Above McMurdo (77.85°S, 166.67°E) From 1994 to 1999

2021 ◽  
Vol 126 (6) ◽  
Author(s):  
Marcel Snels ◽  
Francesco Cairo ◽  
Luca Di Liberto ◽  
Andrea Scoccione ◽  
Marco Bracaglia ◽  
...  
Keyword(s):  
Polar Stratospheric Clouds ◽  
Particle Counter ◽  
Lidar Measurements ◽  
Optical Particle Counter ◽  
Stratospheric Clouds

scholarly journals Characteristics of aerosol and cloud particle size distributions in the tropical tropopause layer measured with optical particle counter and lidar

2007 ◽  
Vol 7 (13) ◽  
pp. 3507-3518 ◽  
Author(s):  
S. Iwasaki ◽  
K. Maruyama ◽  
M. Hayashi ◽  
S.-Y. Ogino ◽  
H. Ishimoto ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cirrus Clouds ◽  
Cirrus Cloud ◽  
Particle Counter ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
Lidar Measurements ◽  
Optical Particle Counter

Abstract. An optical particle counter (OPC) is used in conjunction with lidar measurements to examine the characteristics of the particle size distribution in cirrus cloud in the tropical tropopause layer (TTL) over Thailand where the TTL is defined as the height at which temperature is lower than −75°C in this paper. Of 11 OPC launches, cirrus cloud was detected at 10–15 km high on 7 occasions, cirrus was detected in the TTL in 6 cases, and simultaneous OPC and lidar measurements were made on two occasions. Comparison of lidar and OPC measurements reveal that the cloud heights of cirrus in the TTL varies by several hundred meters over distances of tens kilometers; hence the height is not always horizontally uniform. The mode radii of particles constituting the clouds are estimated by lidar and OPC measurements to be less than approximately 10 μm. The regression lines of the particle size distribution with and without cirrus cloud exhibit similar features at equivalent radii of <0.8 μm. Enhancement in the integrated number concentration at radii greater than 0.8 μm indicates that liquid particles tend to be frozen at a radius of 0.8 μm, with cirrus clouds above 10 km exhibiting similar features. On the other hand, enhancement in the particle size distribution at radii greater than 0.9 μm and a peak at around 0.8 μm in the ratio of the standard deviation of count values to that of the Poisson distribution of the averaged count values are common features of cirrus clouds in the TTL, where the ratio shows the vertical homogeneity of the particle number. These typical features suggest that the transition from liquid, sulfuric acid aerosol, to ice is more observable in the TTL and the timing of freezing may vary with height in the TTL.

10 years of Polar Stratospheric Clouds lidar measurements at the French antarctic station Dumont d’Urville

2020 ◽  
Author(s):  
Florent Tencé ◽  
Julien Jumelet ◽  
Alain Sarkissian ◽  
Slimane Bekki ◽  
Philippe Keckhut
Keyword(s):  
Stratospheric Ozone ◽  
Atmospheric Composition ◽  
Polar Regions ◽  
Primary Role ◽  
Atmospheric Conditions ◽  
Polar Stratospheric Clouds ◽  
Ice Clouds ◽  
Yearly Average ◽  
Lidar Measurements ◽  
Stratospheric Clouds

&lt;p&gt;&lt;span&gt;Polar Stratospheric Clouds (PSCs) play a primary role in polar stratospheric ozone depletion processes. &lt;/span&gt;&lt;span&gt;Aside from recent improvements in both spaceborne PSCs monitoring as well as investigations on PSCs microphysics and modeling, there are still uncertainties associated to solid particle formation and their denitrification potential. In that regard, groundbased instruments deliver detailed and valuable measurements that complement the global spaceborne coverage.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;Operated since 1989 at the French antarctic station Dumont d&amp;#8217;Urville (DDU) in the frame of the international Network for the Detection of Atmospheric Composition Change (NDACC), the Rayleigh/Mie/Raman lidar provides over the years a solid dataset to feed both process and classification studies, by monitoring cloud and aerosol occurrences in the upper troposphere and lower stratosphere. Located on antarctic shore (66&amp;#176;S - 140&amp;#176;E), the station has a privileged access to polar vortex dynamics. Measurements are weather-dependent with a yearly average of 130 nights of monitoring. Expected PSC formation temperatures are used to evaluate the whole PSC season occurrences.&lt;/p&gt;&lt;p&gt;We hereby present a consolidated dataset from 10 years of lidar measurements using the 532nm backscatter ratio, the aerosol depolarisation and local atmospheric conditions to help in building an aerosol/cloud classification. Using the different PSC classes and associated optical properties thresholds established in the recent PSC CALIOP classification, we build a picture of the 2007-2019 events, from march to october.&lt;/p&gt;&lt;p&gt;Overall, the DDU PSC pattern is very consistent with expected typical temperature controlled microphysical calculations. Outside of background sulfate aerosols and anomalies related to volcanic activity (like in 2015), Supercooled Ternary Solution (STS) particles are the most observed particle type, closely followed by Nitric Acid Trihydrate (NAT). ICE clouds are less but regularly observed. ICE clouds also have to be cleary separated from cirrus clouds, raising the issue of accurate dynamics tropopause calculations.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Validation of the spaceborne measurements as well as multiple signatures of volcanic or even biomass originated aerosol plumes strengthens the need for groundbased monitoring &lt;/span&gt;&lt;span&gt;especially in polar regions where instrumental facilities remain sparse.&lt;/span&gt;&lt;/p&gt;

Polar stratospheric clouds over McMurdo, Antarctica, during the 1991 spring: Lidar and particle counter measurements

1992 ◽  
Vol 19 (17) ◽  
pp. 1755-1758 ◽  
Author(s):  
A. Adriani ◽  
T. Deshler ◽  
G. P. Gobbi ◽  
B. J. Johnson ◽  
G. Di Donfrancesco
Keyword(s):  
Polar Stratospheric Clouds ◽  
Particle Counter ◽  
Stratospheric Clouds

scholarly journals A climatological study of polar stratospheric clouds (1989–1997) from LIDAR measurements over Dumont d’Urville (Antarctica)

Tellus B ◽  
2001 ◽  
Vol 53 (3) ◽  
pp. 306-321
Author(s):  
Vincenzo Santacesaria ◽  
A. Robert Mackenzie ◽  
Leopoldo Stefanutti
Keyword(s):  
Polar Stratospheric Clouds ◽  
Lidar Measurements ◽  
Stratospheric Clouds

scholarly journals Characteristics of particle size distributions in the tropical tropopause based on optical particle counter and lidar measurements

2007 ◽  
Vol 7 (1) ◽  
pp. 1595-1622
Author(s):  
S. Iwasaki ◽  
K. Maruyama ◽  
M. Hayashi ◽  
S. Y. Ogino ◽  
H. Ishimoto ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cirrus Clouds ◽  
Cirrus Cloud ◽  
Particle Counter ◽  
Tropical Tropopause ◽  
Cloud Models ◽  
Lidar Measurements ◽  
Optical Particle Counter

Abstract. An optical particle counter (OPC) is used in conjunction with lidar measurements to examine the characteristics of the particle size distribution in cirrus cloud at the tropical tropopause (TT) over Thailand. Of 11 OPC launches, cirrus cloud was detected at 10–15 km high on 7 occasions, cirrus was detected at the TT in 6 cases, and simultaneous OPC and lidar measurements were made on two occasions. Comparison of lidar and OPC measurements reveal that the cloud height of cirrus in the TT varies by several hundred meters over distances of tens kilometers; hence the height is not horizontally uniform. The mode radii of particles constituting the clouds are estimated by lidar and OPC measurements to be less than approximately 10 μm. The regression lines of the particle size distribution with and without cirrus cloud exhibit similar features at equivalent radii of <0.7 μm. Enhancement in the integrated number concentration at radii greater than 0.7 μm indicates that liquid particles tend to be frozen at a radius of 0.7 μm, with cirrus clouds above 10 km exhibiting similar features. In addition, common features of cirrus clouds at the TT include a local maximum in the particle size distribution at 2.0 μm and a peak between 0.5 μm and 1.7 μm in the ratio of the standard deviation of count values to that of the Poisson distribution of the averaged count values. Each feature implies that all ice particles in the clouds may be nucleated by the same mechanism and particles in this size range are actively frozen at the TT. These parameters are thus good indicators for checking the results of cirrus cloud models in the TT.

Sign in / Sign up

Export Citation Format

Share Document