The 4D-clouds Project: Goals, Experiments, Data, and Results

As part of the 4D-clouds project, two major field experiments were conducted in cooperation with the European CLIWA-NET project. BBC 1 and 2 (BALTEX Bridge Campaign) were held around Cabauw, Netherlands, in August/September 2001, and May 2003. Satellite and various ground-based remote sensing observations were combined with in-situ measurements of microphysical and radiative cloud properties from three aircraft. The project was aimed at studying the influence of heterogeneous clouds on radiative fluxes and dynamical processes, ultimately to be used in parameterizations for dynamic atmospheric models, remote sensing applications, and radiative budget studies. An extensive database with 1- and 2-dimensional cloud data, as well as 3-dimensional cloud fields from a statistical cloud generator, and ground-based radiation and meteorological data were created. The goals, experiments, instruments, database, and selected results will be presented in this overview.