Temperature profile inside the container (bold red line) and outside (blue line) during the year 2005. The temperature outside was measured by an automated weather station (daily mean values, AWS 9, IMAU, Utrecht University) installed about 2 km east of Kohnen Station. The yellow area marks the period of unattended operation. We deployed about 1200 kg of liquid water to buffer temperature fluctuations. With these precautions, we succeeded to maintain a temperature of not much below 0°C inside the chamber until May.

Methane sulfonate (MSA, circles) and non-sea salt sulfate (nss-SO42-, triangles) concentrations measured during four years at Kohnen station. Yellow shaded areas mark sampling broke down due to power failure; detection limit for MSA: 2.7 ng m-3 and for nss-SO42-: 4.5 ng m-3.

Na+ concentrations measured during four years at Kohnen station. Detection limit for for Na+: 0.28 ng m-3.