Infrared Radiation Effects of Aerosols in the Atmospheric Window during Wet Growth Process

Aerosols increase the down-welling infrared (IR) radiation flux in the Arctic. The activation of aerosols increases the down-welling IR flux further, depending on the type of the aerosol. A new instrument, NYAEM-FTS has been installed in Ny-Alesund, Spitsbergen to measure the down-welling IR flux. Ny-Alesund is located on the archipelago of Spitsbergen in the most Northern part of the Atlantic Ocean. It is affected by influx of air from Europe and Asia which leads to import of Aerosols from the polluted areas of Europe and Asia.

We use the measurements of NYAEM -FTS for observing (non-activated) aerosols in cloud-free conditions. We improved this algorithm that it can be used for determining the type of activated aerosol as well.

We present first analysis of the IR measurements to show the dependence of the down-welling infrared radiation on the humidity in the aerosol layer and the chemical composition of the aerosols. This helps to close the gap between the warming effect on the Arctic climate of aerosols on one hand and the warming effect of clouds on the other hand.