Science Plan for MNF Investigator cruises over the Southern Ocean

1. Southern Ocean Clouds and Meteorology Workshop, 27 November 2012 Science Plan for MNF Investigator cruises over the Southern Ocean and Cape Grim cloud observations Participants : Alain Protat, Peter May, Eric Schulz, Hongyan Zhu, Lawrie Rikus, Vaughan Barras (CAWCR / BoM) Charmaine Franklin, Stuart Young, Melita Keywood (CAWCR / CSIRO) Christian Jakob, Steve Siems, Michael Reeder, Danijel Belusic (Monash University) Todd Lane (The University Of Melbourne)

2. The Marine National Facility (MNF) New research vessel : the RV Investigator Some numbers : 93.9 m long, up to 300 days at sea per year (60 days max per voyage), can accommodate 40 scientists onboard It is being constructed in Singapore – commissioning should start by 09 / 2013 Relevant instrumentation : dual-pol C-band Doppler radar (owned by MNF), soundings, lidar (CAWCR), radiative fluxes, air-sea fluxes – looking for a cloud radar to complement that. The Centre for Australian Weather and Climate ResearchA partnership between CSIRO and the Bureau of Meteorology

3. MNF Science Plan: Frontal Cloud Systems Study • Most of significant weather in the mid and high latitudes is associated with the fronts along the Southern Ocean storm track. Current climate models also poorly represent the energy balance in that region (although it is apparently getting better). The Southern Ocean environment is very unique in several aspects (pristine air, SLW occurrence, high low-level shear), so we need to uinderstand what causes poor model performances there. • The main objective is to acquire a statistically-significant database about frontal systems and clouds over the Southern Ocean in order to : • Characterize the unique morphological, dynamical, thermodynamical, • and microphysical properties of atmospheric frontal cloud systems • Evaluate satellite active and passive remote sensing cloud and precipitation • products (A-Train) • Analyze the capability of ACCESS and CRMs to reproduce the properties of frontal • cloud systems • Propose hypotheses to explain the large radiation biases in large-scale models • We propose to address this with regular cruises over the Southern Ocean

4. MNF Science Plan: Strategy • Both statistical studies and case-studies will be undertaken. • Statistical verification of the ACCESS model (and WRF) and A-Train products will focus on cloud macrophysics (CFO, top, base, cloud fraction), cloud microphysics (LWC / IWC, particle size, fall speed), frontal dynamics, rainfall, and radiative fluxes at surface and TOA. • Case-studies will be used for : • 1.5 km ACCESS model evaluation of the frontal structure and associated cloud system, with a focus on the interactions between convective clouds and front and the microphysics feedback on boundary layer. • Impact of assimilation of our ship observations on frontal structure and evolution (up to Australia) using the 12 km ACCESS model • Boundary layer process studies (devt of the mixed layer, diurnal cycle of fluxes) • Convective process studies (triggering, dynamics, and heating) • The ISCCP “cloud regimes” over the Southern Ocean will be used as a framework.

5. Status of proposals 1 – Proposal during the commissioning period (Dec 2013 – March 2014) Our proposal was very well ranked scientifically, but given our inexperience at sea, a piggy-back cruise was allocated in September 2013 – this has been cancelled because of ship construction delays. We are waiting on a new piggy-back proposal from MNF (should be around March 2014). 2 – Proposals for 2014-2015 (first call for proposals for scientific cruises) Our proposal, because the strategy has been to do as many piggy-back operations as possible, has been kind of accepted automatically, and they have noted our plans. Once the proposals have been selected, we will get cruises allocated. The period is from december 2014 to march 2015. 3 – 2015 or 2016 : organizing a major Australian-led field experiment ? We have received several expressions of interest (mostly from the US) : Rob Wood, Tom Ackerman, Roj Marchand, Chris Bretherton (Univ. Washington, US) Yong Hu, Gerry Heymsfield (NASA Goddard, US) Jay Mace (Univ. Utah, US) Julien Delanoë (Univ. Versailles / LATMOS, France) Their objectives are : cloud-radiation interactions from local to climate scales, low-level cloud processes, validation of satellite (CloudSat-CALIPSO) products there, including supercooled liquid water, microphysics The Centre for Australian Weather and Climate ResearchA partnership between CSIRO and the Bureau of Meteorology

6. The Cape Grim Site Although it is located a little bit too North to study the main radiation bias in climate models, the nature of clouds and cloud-radiation interactions is expected to be similar, given the very pristine air coming from the west, the very large frequency of occurrence of low-level clouds, etc … The idea would be to augment the current capabilities of the site with cloud active remote sensing (CAWCR lidar will be installed there for one year starting in April 2013, and we are looking for a cloud radar to deploy there as well) – if someone has a cloud radar and / or a microwave radiometer / profiler in his back yard …

7. Questions Who would like to join the Cape Grim effort with instruments / scientific contribution ? Where could we organize to have a ground-based site with cloud radar, lidar, soundings, surface fluxes in the 50-60S latitude band ? Can anyone facilitate that ? Interested in contributing to our MNF science ? Interested in starting discussions on a potential future international campaign ? The Centre for Australian Weather and Climate ResearchA partnership between CSIRO and the Bureau of Meteorology

8. Thank you Alain Protat Southern Ocean Clouds Characterization using CloudSat, CALIPSO, and the ISCCP regimes Email: a.protat@bom.gov.au Thank you