Assessment of Data Quality and Quantity from Airborne Cloud Physics Projects from 1974 through 1984

摘要

Most of the principal airborne cloud physics projects over the past decade are reviewed here to assess the quantity, quality, and availability of microphysical data from clouds above the freezing level. In particular, available information from the projects is analyzed to determine whether adequate data on supercooled liquid water content (SLWC) and snow currently exist for reliably characterizing aircraft icing conditions at altitudes up to 30,000 feet (9 km) over the conterminous United States (CONUS). About 1700 flights in cold clouds over CONUS are documented, and the number and value of flights having data on SLWC, snow, and other hydrometeors are tabulated. Our assessment for SLWC is that there have been an adequate number of flights into supercooled clouds, but there are often serious disagreements between independent LWC indicators when the LWC is greater than about 1 g/cum. Retroactive probe calibration checks in a calibrated, wet wind tunnel may be required to verify individual LWC probe responses or to produce correction factors for past measurements. Our assessment for snow is that the amount of data appear to be adequate for characterizing the sizes and abundance of snow particles at flight altitudes, but about 40% of the data will be from impactors or replicators. If one is willing to accept coarse size and shape classification, then the existing size and shape tabulations for these data will be of value. Otherwise, tedious and time consuming re-analyses of the original images would be required and the use of the impactor and replicator data may therefore be impractical.