Report on the atmospheric lidar observatory in McMurdo and Dome C

1. Report on the atmospheric lidar observatory in McMurdo and Dome C M.Snels Istituto di Scienze dell’Atmosfera e del Clima, CNR, Roma

2. McMurdo LIDAR system 2004-2010 Compact NdYAG laser 532 nm (190 mJ/pulse) 1064 nm (90 mJ/pulse) 14” telescope (35.6 cm) New optical box Chopper @ 400 Hz Photon counting Miniature photomultipliers (Hamamatsu) Low/high channel @ 532 nm 1064 nm channel (APD) Raman channel (607.3 nm) Photon counting acquisition cards (2*2048 bins, Photon - counting , 100 ns bins, 250 MHz Analog operation (not used) 80 MHz, 8 bit

3. Lower Troposphere Channel(1 km- 30 km)Nikon 50mm f/1.8 100 mm pinholeHamamatsu PM

4. McMurdo science • The McMurdo data (2006-2010) have been reclassified by using an approach very similar to the V2 detection and classification scheme for CALIOP. • This allows for a statistical comparison between ground based and satellite based observations of PSCs at McMurdo. • Coincident lidar and OPC observations of PSCs have been analyzed in order to obtain an empirical relation between the backscatter coefficient and the Surface Area Density (SAD) and Volume density (VD) of PSCs

5. Comparison CALIOP vs groundbased McMurdo (2006 June- September) Blue = ice Green = NAT mixtures Red = enhanced Nat mix Orange= STS

6. Comparison CALIOP vs groundbased McMurdo (2006-2010) Vertical distribution 2006-2010 Relative abundances PSC types Blue = ice Green = NAT mixtures Red = enhanced Nat mix Orange= STS

7. Dome C lidar observatory 2014-now Status (1): • The data are of an excellentquality and coverage, due to upgrade of the system and more favorableconditionsat Dome C (wrtMcMurdo) • A new data acquisitionsystemhasbeenimplementedsinceJanuary 2018 • The effect of the viewwindow on the depolarizationhasbeenextensivelycharacterized and a correctionhasbeenapplied to the data. • The remote control of the lidar (from the mainbuildingsat Dome C and from Rome) hasbeenfullyexploitednow.

8. Dome C lidar observatory Status (2): • All data (2014-2017) havebeenuploaded to the NDACC data base. • Thisyearwehave a critical situation, because the laser needs a revision and the spare laser isunrepairable. • Fundingisguaranteed for anothertwoyearsatleast. • A request for a new laser hasbeenapproved by PNRA and thiswillallowus to substitute the old laser in January 2019, and send the old laser to Europe for reconditioning and use itas a workingspare from 2020

9. Dome C lidar observatory • Science: • The Dome C data are being reclassified with an algorithm similar to the CALIOP V2 algorithm and compared with CALIOP data in a ± 2 degrees square around the Dome C coordinates.

10. Dome C vs CALIOP 2014-2017 (preliminary analysis) Blue = ice Green = NAT mixtures Red = enhanced Nat mix Orange= STS

11. Dome C vs CALIOP 2014 (preliminary analysis)

12. Dome C vs CALIOP 2015(preliminary analysis)

13. Dome C vs CALIOP 2016 (preliminary analysis)

14. Papers to be submitted • Marcel Snels*, Francesco Cairo, Luca Di Liberto, Andrea Scoccione, Marco Bracaglia and Terry Deshler “Comparison of coincident optical particle counter and lidar measurements at McMurdo “ to be submitted to JGR • Marcel Snels*, Francesco Colao, Francesco Cairo, Andrea Scoccione, Mauro De Muro, and Michael Pitts, «Polar Stratospheric Cloud observations from Dome C (Antarctica) from 2014 to 2017“ to be submitted… • Marcel Snels*, Federico Fierli, Francesco Cairo, Luca Di Liberto, Michael Pitts, Chiara Cagnazzo, Andrea Scoccione, Terry Deshler, “Comparison of Antarctic polar stratospheric clouds observations by ground- and satellite based lidars and relevance for Chemistry Climate Models», to be submitted to ACP • * corresponding author

15. SAD and VD vs beta