Comparison of Silver Iodide Outputs from Two Different Generators and Solutions Measured by Acoustic Ice Nucleas Counters
AbstractField testing in late September 2009 permitted comparisons of the output of a WMI remote-controlled seeding generator burning a modern solution with an older style AgI generator and solution previously calibrated in the Colorado State University (CSU) Cloud Simulation Laboratory. That facility is no longer available for seeding generator calibrations. Acoustical Ice Nucleus Counters (AINCs), usually operated at -20°C, were used to monitor ice nucleus concentrations from passage of AgI lines released upwind by mobile generators towed approximately perpendicular to the prevailing wind direction. Considerable variability existed for total ice nuclei per AgI plume passage as could be anticipated given variations in atmospheric conditions. However, examination of all tests with useable data revealed no major difference between the outputs of the two generator types using different solutions. The WMI generator uses a newer solution, expected to produce ice nuclei which operate primarily by condensation-freezing in winter orographic clouds. It had yields in the -15 to -20°C range similar to the Montana State University Skyfire generator producing a relatively pure AgI aerosol likely to operate by contact nucleation. However, AINCs with standard configurations as used in this investigation cannot differentiate between ice nucleation processes. The observations also documented that a newly-manufactured AINC compares favorably with previously tested units. Recommendations are made for future testing expanded to warmer temperatures than practical with the standard configurations of the AINCs available for this study.
Authors that submit papers for publication agree to the Journal’s copyright and publication terms. Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the manuscript’s authorship and initial publication in Journal of Weather Modification. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal’s published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in the Journal of Weather Modification. Authors are permitted to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process to encourage productive exchanges and greater citation of the published article.
Articles are published online using restricted access for the first year. After the first year, articles are made freely available online. Immediate open access for an article may be obtained by the author paying an open access fee which is in addition to the normal page changes. Authors are expected to honor a page charge in order to support publication and distribution of the journal. After the author approves the gallery formatted version for publication, the Weather Modification Association’s Secretary will invoice the corresponding author for the page charges and payment is due within 30 days.