J1.1
Commerical aircraft Inadvertent cloud seeding

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Thursday, 27 January 2011: 8:30 AM
Commerical aircraft Inadvertent cloud seeding
605/610 (Washington State Convention Center)
Andrew Heymsfield, NCAR, Boulder, CO; and A. Bansemer, G. Thompson, H. Morrison, R. Rasmussen, Z. Wang, D. Zhang, and P. Minnis

The production of "hole punch" clouds and snow precipitation development in supercooled liquid clouds from turboprop and jet aircraft is documented. Ice is produced by piston through turboprop aircraft via cooling behind the propellers (APIPS) and by private through commercial jet aircraft by cooling over the wings (aerodynamic contrails). Once ice is produced dynamical processes can kick in and cause local updrafts via latent heating in the ice regions and subsidence around them affected region. The updrafts suspend the ice particles which continue to grow and produce latent heating, expanding the updraft area laterally. Using observations and the WRF model, we show that the area of influence can last for two or more hours. Broader implications of this inadvertent seeding will be discussed.