Mike Larsen , Professor at College of Charleston (USA) will present some of work at HM&Co on Monday 14th October at 11:00 in our meeting room. This seminar is part of the activities of the ANR PRCI Ra2DW project.
Title : Disdrometer Measurements: Insights, Limitations, and Future Directions
Abstract:
Rain drop size distributions vary in space and time, and this variability is important to characterize in order to appropriately use remote sensing tools for quantitative precipitation estimation. “Ground truth” measurements of these drop size distributions are frequently made with commercial disdrometers (DIStribution of DROps METERS), most of which are capable of determining individual drop sizes and fall speeds. The individual droplet measurements are then typically aggregated into distributions that are interpreted to characterize the underlying droplet size distribution associated with some spatio-temporal region. Disdrometer data need not be temporally aggregated, however. The disdrometer drop-by-drop data is the highest resolution rainfall data possible and looking at the individual drop record can yield insights into spatio-temporal variability all the way down to the drop scale.
In this presentation, we explore some of the nuanced intricacies of disdrometer-based rain measurement, including a deeper look into instrument design and performance, instrument measurement uncertainty, alternative approaches to data aggregation, and investigation of the underlying physical variability or rainfall in time and space.
It is of particular note that disdrometer drop-by-drop data is structured somewhat similarly to Optical Array Probe (OAP) and/or holographic cloud probe data; the cloud microphysics community has recently developed new techniques to determine time and spatial scales of drop size distribution variability that may be adaptable to precipitation data. The feasibility of utilizing these new approaches on existing disdrometric datasets is discussed.