A modelling approach for optimizing flight patterns in airborne meteorological measurements

A method is presented for selecting the optimal flight patterns for airborn e meteorological measurements in various flow situations. The method is bas ed on systematic utilisation of mesoscale model fields. Flow over an Arctic sea-ice boundary zone is modelled, and it is assumed that the mesoscale mo del fields represent the true state of the atmosphere, and that each possib le flight pattern yields a different sample of the true fields. A plan for the basic structure of the flight pattern is assumed, and then the unexplai ned variance, i.e., the difference between the true variance and the sample variance, of a quantity of interest is calculated for a variety of possibl e flight patterns. Different target quantities are considered, such as wind speed, air temperature, and the turbulent fluxes of momentum and sensible heat. The optimal flight pattern is defined by minimisation of the unexplai ned variance, and often depends on the quantity we are interested in. For s awtooth patterns, the optimal flight pattern was sensitive to the maximum a scent angle of the aircraft. In flight patterns designed for turbulence mea surements, the optimal pattern was different for the unexplained variance o f the turbulent fluxes and for the unexplained total heat content of the co nvective layer.