Science Discipline Overview: Atmosphere (large-scale perspective)  How might large-scale atmospheric challenges add to the scientific arguments for MOSAIC?

Sources  ISAC (International Study of Arctic Change) Science Plan  SEARCH (Study of Environmental Arctic Change): Recommendations for Understanding Arctic System Change (Workshop Report)  Others (WCRP Predictability, IASC/Arctic in Rapid Transition,…)

What is the Arctic Ocean’s role as a source/sink of greenhouse gases, aerosol particles, and other chemical species? [ISAC]

Postulated feedback involving DMS [

800 m Methane flares on the Arctic shelves: Is there a summer signature in the central Arctic [from N. Shakhova and I. Semiletov, IARC]

Arctic seabed methane stores destabilizing, venting Shakhova and Semiletov (2010, Science)

What is the Arctic Ocean’s role as a source/sink of greenhouse gases, aerosol particles, and other chemical species? [ISAC]  Are increases in midlatitudes being augmented or offset by exchanges at the surface of the Arctic Ocean?  Is reduced sea ice cover (area and thickness) altering the Arctic Ocean’s role in the global carbon and sulfur budgets?  Of particular interest: Dimethyl sulfide (DMS) and its role in cloudiness

How much has sea ice loss (area, thickness) contributed to polar amplification of the recent warming? [ISAC]

Change in surface air temperature (°C), [from NASA GISS] Arctic Antarctic

How much has sea ice loss (area, thickness) contributed to polar amplification of the recent warming? [ISAC]  Sensible heat release from ocean (increased solar absorption)  Changes in atmospheric humidity, cloudiness due to enhanced evaporation  Increased influxes of atmospheric heat and moisture from lower latitudes  Increased inflows of oceanic heat from the North Atlantic and North Pacific

Can a station in the Arctic Ocean provide information relevant to springtime ozone depletion? [ISAC]

Total column ozone measured by satellite [Bernhard et al., 2011, Arctic Report Card]

Can a station in the Arctic Ocean provide information relevant to springtime ozone depletion? [ISAC] Measurements of potential utility:  Spectral distribution of downwelling radiation  Upper atmosphere profiles  Others?

Can field measurements support a linkage between reduced autumn ice coverage and wintertime atmospheric circulation anomalies affecting middle latitudes?

Latitude-height section of temperature anomalies ( ºE) Oct-Dec, [Overland and Wang, 2010, Tellus]

mb thickness anomalies Oct-Dec, [Overland and Wang, 2010, Tellus]

Can field measurements support a linkage between reduced autumn ice coverage and wintertime atmospheric circulation anomalies affecting middle latitudes?  Enhanced heating of upper ocean in recent summers is substantial (Perovich et al.)  Subsequent release of heat to the atmosphere is not fully understood (i.e., temporal, vertical distributions) – but warming of the lower troposphere is strongly indicated  Mechanisms linking midlatitude weather/climate anomalies to heating of Arctic troposphere need elucidation

How much is the atmosphere contributing to the extreme ice retreat of recent summers? [ISAC]

Satellite-derived cloud fractions, June-August [Stroeve et al., 2011, Climatic Change]

% of sea ice retreat explained by wind (black, blue) downwelling longwave (green), and sensible hear flux convergence (red) [from Francis et al., 2005]

Arctic Ocean temperatures from NABOS moorings,

How much is the atmosphere contributing to the extreme ice retreat of recent summers? [ISAC] Factors to be included in quantitative diagnosis:  Downwelling radiation anomalies (clouds, water vapor)  Wind forcing/ice advection  Atlantic and Pacific water inflows and  Effects of changes in surface albedo

How do storm events interact with the ice cover and upper ocean? -- effects of storms on the ice/ocean state -- effects of lower boundary changes on storms

Polar low in Chukchi Sea (2009) Contours: geopotential height at 500 hPa; Color: SLP. The polar low developed after a synoptic scale cyclone intruded into the Chukchi Sea. Mirai soundings crucial to diagnosis, initialization of WRF Moreira et al. 2012

Targeting special observations to enhance weather forecasts – the Norwegian IPY-THORPEX success (Kristjansson et al., 2011) special obs no special obs ← verifying analysis L L L

How do storm events interact with the ice cover and upper ocean? -- effects of storms on the ice/ocean state -- effects of lower boundary changes on storms  Atmospheric soundings from vicinity of polar low have been found to enhance regional model simulations of system  Surface fluxes should be important to the development of the system  Boundary layer parameterization packages are many – choice of most appropriate modules need observational guidance