10 years of stratospheric aerosol observadons from CALIPSO J.-P. Vernier, L.W. Thomason, T.D. Fairlie, J. Kar, M. Natarajan

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1 10 years of stratospheric aerosol observadons from CALIPSO J.-P. Vernier, L.W. Thomason, T.D. Fairlie, J. Kar, M. Natarajan CALIPSO-Cloudsat 10th Anni versary workshop, June 2016, Paris

2 Some important results about stratospheric aerosols since ~10 years - Increase of stratospheric aerosol loadings during the period likely contributed to reduce global warming (by ~25%). - Moderate volcanic erupdons played a major role in supplying the stratosphere in aerosol - Some disrupted the air traffic for several weeks (e.g Pueyhue- Cordon) - In absence of erupdon, polludon can reach the stratosphere during the Summer Asian Monsoon resuldng in the formadon of aerosol layers CALIPSO obs. have had contribudons to these findings!

3 Stratospheric aerosol layers above Africa Backsca]er sonde August 2006 OpDcal ParDcle Counter AlDtude (km) August,7th August,17 th Sca]ering RaDo (SR) - Aerosol layers observed during the SCOUT-AMMA campaign - Deep convecdve transport of pardcles into the UTLS by the Western African monsoon? SR = β ( +//)532 β m

4 CALIOP first obs. June 2006 A B PolluDon over Europe Saharan dust Saharan dust? A B - Layer between ~18-20 km above deep convecdve clouds over Africa - Could dust be transported in deep convecdve clouds in the UTLS? - Non-depolarizing layer : likely not dust

5 CALIOP observadons of the Soufriere Hills plume SR km Diagram of depolarizadon 20N-20S Ice plume Longitude Zonal ladtude - Layers between km over the tropical belt (leg panel) - DisDnct opdcal properdes between ice clouds and this aerosol layer (low depo.) - Soufrière Hills erupdon on May, 20 th (0.5 Tg) / Mt Pinatubo ~(10-20Tg)

6 CALIOP obs. of stratospheric volcanic layers CALIOP: 20N-20S AlDtude (km) Vf So Ta Ka Sa Me Na Ke Ca Trop + 5km LaDtude So Ta Ka CALIOP: Trop-Trop+5km Sa Na Me Vf Co Ke tropopause Ca Volcanic plumes + 1 Smoke plume observed since Upward transport above 20 km within the tropical stratosphere - - Meridional transport exchange between tropics and midladtudes

7 CALIOP in the bigger picture 20N-20S AOD 20N-20S : km Aerosol to Molecular ExDncDon rado - Merged stratospheric aerosol datasets with SAGE II/GOMOS/CALIOP - Major influence from Mt Pinatubo followed by moderate erupdons in the 2000 s. - Core of the satellite stratospheric aerosol dataset provided to CCMI / CMIP6 (+OSIRIS)

8 RadiaDve/Climate impacts of moderate erupdons : RF (W/m2) Anderson et al. (2015) RadiaDve Forcings comparison (CO2 ~0.3 W/m2) between (courtesy S. Solomon) Solomon et al. (2011); Fyfe et al. (2011); Santer ( ) Anderson et al. (2015) showed the climate importance of medium size erupdon (RF ~-0.5 W/m2) with stadsdcally significant impacts on shortwave RF, tropospheric temperature and SST.

9 Volcanic ash and aviadon Puyehue-Cordon Caulle ErupDon 4 June weeks ager the erupdon MODIS 6 June 2011 Ash Advisory from Darwin VAAC on 06/21 - Air traffic disrupted in most of the Southern Hemisphere more than 2 weeks ager the erupdon - Plume circumnavigadng several Dmes the world (e.g. Australia)

10 Cordon ash clouds observed by CALIOP/IIR Color rado Backsca]er 06/23 06/23 DepolarizaDon 06/ Swath (km) Unusual muld laminar layers with low color rado (0.5) and high depolarizadon ( ) observed by CALIOP - NegaDve BT from InfraRed Imager - Consistent with small volcanic ash from Cordon

11 Trajectory mapping of CALIOP New Zealand 06/21-06/25 Ensemble of trajectories Australia Volcanic ash clouds Vernier et al., 2013 JAMC Total Backsca]er Cordon plume dispersion between Australia, AntarcDca and New Zealand Trajectories inidalized at CALIPSO obs. Of the plume and run forward in Dme ObjecDve : trajectory mapping of CALIPSO obs. of volcanic ash clouds to improve the Dme and space coverage of the CALIOP data alone

12 Improving Ash Advisories for aviadon safety CALIPSO-trajectory mapping Now cast from Darwin VAAC FL200-FL400 (8-13 km) - Absence of Ash Advisory over SE Australia (Sydney) on 06/21. - CALIPSO-trajectory map capture the head of the plume over Sidney. - RetrospecDve exercise prove that Lidar data can be used by the VAACs if available within 48 h at least.

13 SAM andcyclone Transport of polludon into the UTLS linked to deep convecdon in Summer Asian Monsoon MLS/CO July-Aug hPa Park et al. (2007) (Lawrence and Lelieveld., ACP, Summer Asian Monsoon (SAM) can provide a vehicle for transport of BL gas-phase pollutants (e.g. CO, HCN, CH4) into the UTLS (Park et al., 2007; Randel et al., 2010, 2011). Do aerosols also transported or/and formed in the UTLS during the Summer Monsoon?

14 The Asian Tropopause Aerosol Layer: South AtlanDc Anomaly ATAL associated with SAM andcyclone ATAL extends from top of convecdve ouslow Vernier et al., JGR 2015! Cloud clearing of CALIPSO backsca]er using 532 nm depolarizadon cutoff of 5% reveals ATAL! Buildup of enhanced aerosol associated with Summer Asian Monsoon andcyclone! Extends from top of convecdve ouslow (black contour) in much of SE Asia

15 Balloon-borne measurements of the ATAL km 08/10 - CALIPSO validadon through in situ backsca]er measurements (COBALD) - First ATAL s size distribudon from OpDcal ParDcle Counters (Univ Wyoming) : small (r<0.15 micron) and voladle pardcles (liquid and spherical) - BATAL 2016 will focus on ATAL s composidon

16 Conclusions CALIOP provided key measurements of stratospheric aerosol since 2006 to : Highlight the role of moderate volcanic erupdons on climate. Be merged with other datasets (SAGE II/GOMOS) and soon SAGE III/ISS for climate simuladons (e.g. CCMI, CMIP6) Be used for providing ash info for the VAACs (by including info from IIR) Demonstrate the importance of volcanic ash on climate ogen neglected * (not had Dme to speak about that). CALIPSO mission is ending : follow up (CATS/short mission), EarthCare (one channel 355 nm) : homogeneity of space-borne lidar record? Need a quick, smaller and cheaper follow up of CALIPSO with the same capabilides before a space-borne HSRL lidar.