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UP: Fachverband Umweltphysik

UP 2: Atmosphäre

UP 2.3: Vortrag

Mittwoch, 25. März 2015, 09:45–10:00, G/gHS

Spatio-Temporal Variability of Water Vapor Investigated by LIDAR and FTIR vertical soundings above Mt. Zugspitze — •Hannes Vogelmann, Ralf Sussmann, Thomas Trickl, and Andreas Reichert — IMK-IFU, Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Germany

We quantitatively analyzed the spatio-temporal variability (minutes to hours, 500 m to 10 km) of integrated water vapor (IWV) and water vapor profiles in the free troposphere above Mt. Zugspitze (Germany). Our data have been measured with a differential absorption lidar (DIAL, Schneefernerhaus, 2675 m) and a solar FTIR (summit, 2962 m). This investigation benefits from the arrangement of one zenith-viewing and one sun-pointing instrument 680 m away from each other and the temporal resolution of the instruments. Within a time interval of 20 min, the spatial variability of IWV becomes significant for horizontal distances above 2 km, but only during the warm season (0.35 mm). The temporal variability of IWV increases from 0.05 mm within 5 min to more than 0.5 mm within a time interval of 15 h. The vertical profile variability has a minimum at about 4.5 km a.s.l. and peaks in the tropopause region. We found that the long-range transport of heterogeneous air masses may cause short-term variations of the water-vapor density which exceed the impact of local convection by one order of magnitude, even near the ground. Our results demonstrate the importance of closely co-locating H₂O instruments for investigations together with other atmospheric sensors or for quantitative validation. Our findings could also be useful for model parametrization.