The polarization diversity-radar (POLDIRAD) of DLR has extensively been used for thunderstorm research in the south German area. By polarimetric measurements it is possible to discriminate between different kinds of hydrometeors like raindrops, snow, graupel or hailstones (Hoeller et al., 1994). These methods enable an improved study of hail growth processes in severe storms. The Doppler capabilities allow to infer the principal dynamical features of thunderstorms like updrafts or downdrafts, convergence and divergence patterns, rotation or gust fronts. The radar was also used to study mesoscale weather systems as demonstrated by Meischner et al. (1991) for the case of a severe squall line.
A six years statistics of the hailfall and hailstorm characteristics as well as of the meso-scale organization of the storms was performed by Hoeller (1994). On the one hand, the cells were classified according to evolutionary characteristics as ordinary cells, multicells and supercells. On the other hand, microphysical features as induced from the polarimetric measurements were applied to discriminate between rain and hail producing (fallout at the ground) cells. On the larger scale the convection was classified as isolated storms, storm clusters, line-storms, and squall lines.
In MAP it is intended to extend these types of analyses to a longer time period as well as to a larger region by including Swiss and Austrian radars (project HERA). The focus will be on the study of severe precipitating systems (MPS) affecting the Alpine region. Based on radar monitoring, a homogenized classification and climatology of the MPS will arise from such an analysis. Moreover, the relation of MPS events to supra-scale meteorological structures will be studied. The results will be usefull for an assessment of thunderstorms and MPS related risks in a changing climate.
Hoeller, H., V. N. Bringi, J. Hubbert, M. Hagen, and P. F. Meischner, 1994: Life cycle and precipitation formation in a hybrid-type hailstorm revealed by polarimetric and Doppler radar measurements. J. Atmos. Sci., 51, 2500-2522.
Hoeller, H., 1994: Mesoscale organization and hailfall characteristics of deep convection in Southern Germany. Beitr. Phys. Atmosph., 67, 219-234.
Meischner, P., V.N. Bringi, D. Heimann, and H. Hoeller, 1991:
A squall line in southern Germany: Kinematics and precipitation
formation as deduced by advanced polarimetric and Doppler radar
measurements. Mon. Wea. Rev., 119, 678-701.
MAP Data Centre - April '05 - MAP WebMaster