Dust as a Tracer of Climate Change in Antarctica and as modulator of Phytoplankton Activity Ice core records show a correlation of dust deposition and temperature changes (Recent and in geological times) McConnell et al, PNAS, 2007 Phytoplankton activity is very sensitive to changes in nutrient availability (particularly in the Southern Ocean) Soiree Experiment, Edward et al, Nature 407, (12 October 2000) | doi: / Artificially seeded Fe in the SO Chlorophyll visible for several days afterwards A combination of MODIS and OMI observations shows dust traveling a long way in the South Atlantic MODIS Aerosol Optical Depth OMI Aerosol Index Observation of dust in the SO is very difficult because: Very cloudy --- > very few clear sky retrievals > sampling problem Dust activity is episodic and in pulses. Only a combination of satellite retrievals can help to understand dust transport and detection in the SO as this example shows. Indirect Effects from Degassing Volcanoes can be comparable to human effects Weakly explosive volcanoes play an important role in the sulfur cycle and radiative forcing. Estimation is model dependent due to parameterization and emissions height inventory Very poor global characterization of degassing activity of volcanoes. Anthropogenic (a),Volcano (b), DMS (c ) Radiative forcing- Graf et al, 1997 Observations of the impact of weak volcanic activity on clouds A natural laboratory for studying the indirect effect First observation of a naturally occurring phenomena similar to man- made ship-tracks Used two-satellite platforms to characterize the event.