CrazyC83 wrote:I think 1971-75 is still at least a couple years ago. Checking out the new findings now.
One interesting case that the recent reanalysis covered is that of Debbie (1969). On 18 and 20 August 1969 Project STORMFURY, as is well known, seeded Debbie with silver iodide, and the metadata indicate that Debbie apparently underwent or commenced eyewall replacement cycles on those two dates. The aircraft recorded a 31% decrease in Debbie’s MSW on 18 August and an 18% decrease on 20 August, respectively. While the reanalysis suggests that the ERCs were the responsible for these changes, what is still unclear is whether the seeding had any impact on the initiation of the ERCs themselves. A close look at the metadata suggests that the seedings did not have much of an effect.
Per aircraft radar, on 18 August the diameter of Debbie’s eye increased from ~24 n mi at 11:55 UTC to ~40 n mi at 17:52 UTC. Debbie’s eye maintained a ~40-n-mi diameter through 12:02 UTC on 19 August. The eye subsequently shrank to ~20 n mi by 18:36 UTC on the same date. On 20 August the diameter of Debbie’s eye fluctuated between ~20–30 n mi throughout the day, but the very last reconnaissance fix, at 23:43 UTC, on that date indicated inner and outer eyewalls whose diameters were ~17 and ~35 n mi, respectively. The first ERC took about a day to complete and the latter started little more than a day later than the first’s completion.
Overall, the progression of the posited ERCs seems to have been fairly normal, so the effects of the seedings, if any, appear to have been rather minimal.