Climate model simulations have to be validated by past observations from the real atmosphere. Within MiKlip Module E, MOSQUITO aims to validate MiKlip global and regional hind-casts from MODULEs A to D by comparing simulated and observed profiles of the essential climate variables (ECVs) temperature, relative humidity, wind, and ozone throughout the free atmosphere, from the low troposphere up to the mid-stratosphere. MOSQUITO will use routine meteorological radiosonde and ozonesonde data from a set of German, European and world-wide stations. Contrary to many satellite measurements, profiles from balloon sondes have quite good height resolution. On decadal time-scales, however, radiosonde changes can affect long-term data consistency (Seidel et al., 2004, Free et al. 2005, Haimberger et al., 2008; Steinbrecht et al., 2008, Miloshevich et al., 2009, Sun et al. 2010). In MOSQUITO we will collect radiosonde data, screen for quality, correct for sonde-changes, and use the resulting improved data sets for MiKlip model validation.
Time series of radiosonde data allow climate change and variability investigations, e.g. looking at atmospheric circulation patterns, teleconnections, and stratosphere-troposphere connections. These modes are potentially important for long-range weather forecasts and mid-range climate prediction (Thompson and Wallace, 2001; Baldwin and Dunkerton, 2001). In the troposphere, the El-Nino/ Southern Oscillation phenomenon (ENSO) is a major player (Latif, 2006). In the stratosphere, longer-term variations on decadal, inter-annual and weekly to monthly time-scales are well known. They can be attributed to the 11-year solar cycle, to the quasi-biennial oscillation of equatorial winds (QBO), and to vacillations in the strength of the polar winter vortices (van Loon and Labitzke, 1988; Steinbrecht et al., 2006). Radio- and ozonesonde data contain substantial information about these modes of variability, and within MOSQUITO we want to explore this.