A comparison of the turbulent characteristics of cumulus clouds measured near Yellowknife and Thunder Bay

• Main Author: Macpherson, J. I.
• Format: Report
• Language: English
• Published: National Research Council of Canada. National Aeronautical Establishment 1979
• Subjects: Thunder Bay; Yellowknife
• Online Access: https://nrc-publications.canada.ca/eng/view/object/?id=472106d2-6a86-4f04-a6bf-c7095d0dde0e; https://nrc-publications.canada.ca/fra/voir/objet/?id=472106d2-6a86-4f04-a6bf-c7095d0dde0e

While serving as the seeding aircraft in a rainfall enhancement research program, the NAE (National Aeronautical Establishment) T-33 atmospheric research aircraft made turbulence measurements in the tops of towering cumulus clouds near Yellowknife, N. W. T. and Thunder Bay, Ontario. Since the T-33 penetrations all tended to occur at roughly the same stage of each cloud's lifetime, and at about the same height below cloud top, the data collected afford the opportunity to compare the dynamical characteristics of cumuli measured over forested lakeland within 350 km of each location. Data from 28 penetrations of 15 clouds at Yellowknife are matched with an equal number of gust records collected in 18 Thunder Bay clouds. Included among these clouds are 21 of the total of 25 seeded with silver iodide during this experiment. Comparisons of the RMS and peak gust velocities, spectra, turbulent energy dissipation rates, and aircraft vertical accelerations all indicate that on the average the tops of cumulus clouds in the Thunder Bay area were more turbulent than their counterparts at Yellowknife. Reprinted from: DME/NAE Quarterly Bulletin, no. 1979 (1). Réimprimé de: DME/NAE Quarterly Bulletin, no. 1979 (1). Peer reviewed: Yes NRC publication: Yes