A high-altitude long-range aircraft configured as a cloud observatory: The NARVAL expeditions

Abstract : A configuration of HALO (the High-Altitude LOng-range research aircraft) as a remote sensing cloud observatory is described and its use is illustrated with results from the first and second NARVAL (Next-generation Aircraft Remote-sensing for VALidation) field studies. Measurements from NARVAL2 are used to highlight the ability of HALO, when configured in this fashion, to characterize not only the distribution of water condensate in the atmosphere, but also its impact on radiant energy transfer and the co-varying large-scale meteorological conditions – including the large-scale velocity field, and its vertical component. The NARVAL campaigns with HALO demonstrate the potential of airborne cloud observatories to address long-standing riddles in studies of the coupling between clouds and circulation, and are helping to motivate a new generation of field studies.