Summary of Session 3 (16 talks) A. Protat, S. Siems, R. MarchandTalk 1: Kalli Furtado (UKMO)

SO SST bias linked to lack of SLW clouds in the UM modelDeveloped a new parameterization using turbulence to generate mixed-phase cloudsUsed LES to test the parameterization : works wellImplemented in GCM 4 Wm-2 reduction of SW

Differences from CERES EBAF

Talk 2: Erica Dolinar (North Dakota)Compared cloud fraction, cloud water path, w, TOA radiative fluxes (30S-70S ) from AMIP simulations (2000-2008), 28 models ensemble mean and spread NASA products (CloudSat, CALIPSO, CERES, MODIS) & MERRA analysesGCMs underestimate cloud fraction by 12 % (worst for 30s-45S and for low-levels), CWP by 56 gm-2 (worst in the 45S-60S), general patterns of vertical velocity OK but differences in subsidence region. The magnitude of TOA SW (LW) CRF cooling (warming) is underestimated. Not consistent with CF and CWP results …

Talk 3: Ryan Stanfield (North Dakota)Assessment of NASA GISS CMIP5 and post-CMIP5 – clouds and TOA radiation using satellite data (A-Train). Changed cumulus & BL turbulence params general improvement over SO but new version probably overestimating low cloud cover.

NEW OLD

cloud response SST anomalies jet shift

Talk 4: Paulo Ceppi (Washington)Analyzed in detail the causal relationship between SW radiation changes, SST, and midlatitude jet shift. A very nice correlation is found between change in ASR gradient and change in SST gradient. Also between change in ASR gradient and poleward jet shift

jet shift cloud shift SST anomalies

1

2

Spread in ASR response due to model-dependent sensitivity to SST warmingMinor role played by poleward shift

Talk 5: Ying Li (CSU)Studied the instantaneous linkage between cloud vertical structure and 6 LS paramsUses 2B-GEOPROF-LIDAR and ECMWF-AUXThis provides a very nice framework to evaluate GCMs. We should consider it together with the ISCCP regime or other state-classifications.

Maximum at high LTS

e.g., stratocumulus clouds

Maximum at low LTS

e.g., stratus associated with extratropical synoptic storms)

Dual maxima: different types of clouds throughout the mid/high latitude

Hei

ght (

km)

Talk 6: Roj Marchand (U. Washington)Recent changes in SO cloud fraction using CTH-OD diagrams. No signature on global total cloud fraction but clear reduction in CF for clouds with OD > 23. Our SOCRATES area is spot on. Not due to a change in LS atmospheric state but a change in cloud properties within states with regions of low pressure. Change islargest in winter, and it was suggested that experimental goals need to include sampling winter and summer seasons.

Talk 7: Daniel McCoy (U. Washington)Studied the effect of cloud properties on upwelling SW radiation with special attention on the increase in SW from transition from ice to liquid transitionSummertime : peak in low CF and reduced Reff. Seasonal cycle of phase.Radiative transfer calculations changing cloud microphysics parameters individually show the respective contributions to upwelling SW (CF and Reff both contribute).

Ice to liquid transition over the seasons strongly affect the upwelling SW but magnitude highly varies with assumed microphysicsTake home : better understanding of cloud microphysical processes is needed to better constrain the optical depth feedback.

Talk 8: Jay Mace (U. Utah)Studied the microphysical properties of marine low clouds, precipitation susceptibility, and the variability due to environmental factors. Also gave a word of caution about the use of ISCCP regimes.

The co-dependence of albedo susceptibility and precip susceptibility shows large variability between summer and winter. Both seasons should be sampled …

Talk 9: Steve Siems (Monash)Analyzed the BL structure and precip properties from soundings at Macquarie IslandMet. Records are available since 1948. There is a clear problem with ERA-Interim winds below 500 m height. Reports a 35% increase in precip between 1970 and 2008 (wintertime) and surface wind increase by 3 cm/s a year since 1991. Identified the “buffer layer” on Macquarie soundings. Not present on YOTC analyses (too smooth).

Talk 10: Adrian McDonald (U. Canterbury, NZ)Presented the main objectives of research in NZ under the “Deep South” National challenge. A major priority will be the polar influences on the westerlies which are a main driver for weather over NZ. Strong climate modelling and atmospheric remote sensing activities planned. Auckland Island sites will be instrumented. Many people (including me!) discovered the potential of WindSat for these studies (launched in 2003, provides a host of products). Studied the impact of SAM on properties measured by WindSat.

Zonal wind (m/s) Meridional wind (m/s) SST(K)

TCWV (%) Cloud Liquid water (%) Rain rate (%)

Talk 11: Kalli Furtado (UKMO)Highlights a problem with low stratiform clouds in cold air outbreaks of the NH. Even when using high-resolution (km scale) model. Research aircraft flights have been performed to better understand this problem. Significant underestimate in surface moisture flux due to enhanced water vapour in the model near the surface has been found. Building a comprehensive database.A similar problem is expected over the Southern Ocean (?).

Satellite Control model Modified model

Talk 12: Tom Lachlan-Cope (British Antarctic Survey)Described the Meteorological Airborne Science INstrumentation (MASIN). Twin Otter equipped for sea ice, clouds, aerosols, radiation. 150 flight hours done. Found that models do not reproduce the energy balance very well. Documented the average droplet number concentration on both sides of the peninsula. (unexpected ?) Discussed upcoming activtiteis with aircraft and surface measurements and plans to support ACRE.

Talk 13: Simon Alexander (AAD)Described the ACRE proposal to be submitted to AAD call for science proposal. 1 year deployments of a comprehensive suite of clouds, aerosol, precipitation and radiation measurements at Macquarie Island (54S) and Davis (69S).Objectives are to characterize cloud and aerosol properties and their modes of variability, evaluate satellite products, and model simulations (climate to high-resolution).

Talk 14: Scott Collis (ANL)Shared his expertise and gave recommendations on C-band Doppler radar data processing. Described some of the algorithms they have recently developed / implemented. Recommended recording spectra to help filter out (sea-ice) clutter. Slow antenna rotation for good data quality. Recommends the use of Kdp – attenuation then rain rate from attenuation. Demonstrated a technique to get at the number of rain features exceeding rain rate threshold and use that for model evaluation.

Talk 15: Jeff Stith (NCAR)Described the NCAR aircraft characteristics and instrumentation (C130 and G-V). Also showed impressive results with a new cloud probe called HOLODEC-II.Presented CESM modelling evaluation using the HIPPO flights. We want these aircraft ;-)

Talk 16: Gijs De Boers (U. Colorado / NOAA)Described the UAS developments. Advantages of such platforms are enhanced profiles, the characterization of the spatial variability, and sampling over water.Prices range from 1000 to about 5000 US$ (almost expendable).Currently instrumented for P, T, RH, winds, aerosol SD. Working on cloud microphysics and atmospheric radiation.Main risks for deployments over the SO are high winds, icing, wildlife.We want these aircraft too ;-)