Hello again Dave,
As I'm sure you know, Bernie & Kurt were brothers. Through the former (a very close friend) I met the latter a few times. Both generous & great people! Cheers, John. ************* Quoting "Hawkins, Dave" <dhawk...@nrdc.org>: > not to be confused with Kurt Vonnegut's ice-nine > > ________________________________ > > From: John Latham [mailto:john.latha...@manchester.ac.uk] > Sent: Friday, February 20, 2009 2:25 PM > To: Hawkins, Dave > Cc: geoengineering > Subject: Cloud Seeding - State-manufactured snowfall closes 12 highways > > > > Hello Dave et al, > > The role of silver iodide AgI in precipitation formation is to initiate > the freezing of supercooled water cloud droplets at temperatures (below > 0C) too warm for freezing of such small particles to occur naturally. It > works well because the molecular bond-length in AgI is very close to > that in ice, as Bernard Vonnegut (originator of this seeding technique) > first noticed. The tiny ice particles grow rapidly in the supersaturated > cloud, acquiring classical hexagonal shapes. These ice crystals collide > and aggregate to form snowflakes, which eventually settle to ground. I > cannot see where "moisture retention" comes into the equation. > > Silver iodide does not act as a nucleus for water drop formation (only > for ice). > > Cheers, John. > > > *************** > > > Quoting "Hawkins, Dave" <dhawk...@nrdc.org>: > >> Whoops. >> (but consider the mitigation due to a day or so of no driving) :>) >> >> CHINA: State-manufactured snowfall closes 12 highways (02/20/2009) >> >> >> >> Chinese officials were forced to close 12 highways in the >> drought-plagued Hebei province around Beijing after artificially >> "enhanced" clouds dropped heavy snowfall, the state-run news agency >> said. >> >> The clouds were seeded by 313 cigarette-sized capsules of silver > iodide >> shot into the sky, a procedure to increase the clouds' ability to > retain >> moisture. >> >> On the bright side, officials expect the snowstorm to help bring an > end >> to Beijing's longest drought in 38 years, according to weather bureau >> records. >> >> "The snow has brought moisture to the soil, which may help end the >> drought," Guo Yingchun, a senior engineer in the provincial >> meteorological observatory, was quoted as saying. >> >> In all, 12 outbound highways were shut down, including one linking the >> capital with Shenyang, capital of the northeastern Liaoning province >> (Nick Macfie, Reuters >> <http://in.reuters.com/article/environmentNews/idINTRE51I10X20090219> > , >> Feb. 19). >> >> >> >> > >> > > > > -- > John Latham > > lat...@ucar.edu & john.latha...@manchester.ac.uk > > Tel. 303-444-2429 (H) & 303-497-8182 (W) > > > > > -- John Latham lat...@ucar.edu & john.latha...@manchester.ac.uk Tel. 303-444-2429 (H) & 303-497-8182 (W) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---