Observations of Stratospheric Aerosols over Sondrestrom, Greenland Injected by Russia's Sarychev Peak Volcano

Volcanic stratospheric aerosols affect global climate by influencing the radiative budget and chemistry of the lower stratosphere. Presently the stratospheric aerosol levels are in a background state. This provides the opportunity for studies of stratospheric injections by small volcanic eruptions. A thin stratospheric aerosol layer was identified during the month of July, 2009 using the Arctic Lidar Technology (ARCLITE) System operated at Sondrestrom. Trajectory analysis points to the source of the aerosols being the Sarychev Peak volcano in the Russian Kuril Islands. Latitudinal observations of the layer were made by the NOAA/Earth System Research Laboratory/Global Monitoring Division’s (GMD) stratospheric lidar network (Boulder,CO; Mauna Loa, HI; and Pago Pago, American Samoa). These observations show a significant increase in aerosol backscatter levels compared to the low background levels observed prior the eruption. Profiles derived from the from the ARCLITE observations include depolarization, backscatter and temperature which allow for a characterization of the layer on a daily basis. The ARCLITE observations also provide a time series of measurements showing the evolution of the aerosol layer over the month after the injection within the context of the less frequent profiles provided by the global GMD network. From the optical qualities observed, the exact nature of the aerosols and their role in the radiative budget and stratospheric chemistry are elucidated. These types of observations are unique to ground based lidar systems like ARCLITE due to the optically thin qualities of the layer which prevent detection in the visible band by nadir looking satellites. The long-term effect of this injection of sulfur dioxide into the stratosphere may influence the formation of type 1b polar stratospheric clouds during the coming winter.