Assessing the Presence of Supercooled Liquid Water and Stability Using Radiometer Data Collected during the 2015-2016 Winter Cloud Seeding Program in the Upper Gunnison River Basin, Colorado


  • Stephanie D. Beall North American Weather Consultants, Inc.
  • Don A. Griffith


Weather Modification Operations, Weather Modification Research


During the 2015-2016 Winter Cloud Seeding Program, a Radiometrics microwave radiometer was installed in the Upper Gunnison River Basin cloud seeding target area.  The main purpose of using this device was to provide the ability to measure temperature and liquid water in frequent vertical profiles of the atmosphere above the radiometer.  With observations of these two variables, the presence of supercooled liquid water can be identified. This information may be used in real-time to determine the “seedablity” of naturally occurring winter storms that impact the target area. Data may also be used in the post-analysis of these winter storms. For example, the radiometer data used in conjunction with the Rawindsonde Observation Program (RAOB), can be used to generate a vertical sounding of temperature dew point (no winds are observed from these radiometers). Such plots can be used to assess lower level atmospheric stability during storm periods that contain “supercooled” liquid water, which is the target of glaciogenic winter cloud seeding programs.   The ensuing analyses indicated that stability is present in the lower valley levels upwind of the target area during most winter storms but that these inversions have a negligible effect on seeding operations primarily due to the very shallow nature of these inversions. Radiometer data were also compared to a nearby ground-based icing meter to determine if there was any correlation between the two types of observations.






Technical Notes and Correspondence