84th AMS Annual Meeting

Monday, 12 January 2004: 11:15 AM
The Tornado reconnaissance aircraft of the German Airforce as a measurement system in a meteorological campaign
Room 618
Jens Bange, Aerospace Systems, Braunschweig, Germany; and P. Zittel and T. Spiess
Joint field experiments like the LITFASS campaigns investigate the energy exchange between the earth surface and the atmosphere using various methods and systems. The general goal of many of these campaigns is to help with the improvement of numerical climate and weather predictions. The LITFASS 2003 experiment near Lindenberg (60 km south east of Berlin) was one of the largest campaigns carried out in Central Europe for years. Research groups from all over Germany and the Netherlands observed mainly the water transport in the soil and the atmosphere of a heterogeneous terrain with a distribution of grassland, forest, agriculture, and lakes that is typical for Central Europe. Beside ground-based stations, wind profiler, LIDAR, SODAR, scintillometers, and a 99 m tower, two airborne systems performed research flights. The helicopter borne turbulence probe Helipod measured wind, humidity, air and surface temperature during mainly low-level flights as before in 1997, 1998, and 2002 at this site. Completely new to the German meteorological community was the use of combat aircraft for research purpose.

The Tornado aircraft of the 51th reconnaissance squadron 'Immelmann' are equipped with high-resolution infrared cameras. Due to its high air speed the infra-red camera aboard the Tornado aircraft covered the experimental site of about 20 km times 20 km in less than 30 minutes. The surface temperature distribution changed slowly, so these photographies represent snapshots of the surface temperature of the entire area. Since the Tornado cameras use analog technique (chemical films) the spatial resolution is in the order of a meter or (depending on aircraft's altitude) even better. The first impressive result of the analysis of these photographies is that the heterogeneity of the experimental site was much stronger than assumed by the numerical models used so far. Especially the influence of the water content of different soil types is clearly visible.

The infrared pictures sampled by the Tornado aircraft provide relative temperature distributions and are not calibrated. For the usual reconnaissance task the camera systems are optimized for a maximum contrast and not for absolute temperature measurements. But via the comparison with simultaneous measurements of other involved systems these gray-scale photographies can be temperature-calibrated. Especially the horizontal flights at low altitude with the Helipod provide an excellent calibration tool. The measurements at several ground stations give the opportunity for data quality control and cross-validation. During the LITFASS 2003 campaign the Landsat satellite made several flights over the experimental site. The next step will be the comparison of Landsat data with temperature maps obtained from Tornado flights.

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