MCGRATH@OZ.AI.MIT.EDU ("Jim McGrath") (01/03/86)
Staring in Space Digest, Volume 6 : Issue 58: > From: Paul Dietz <dietz%slb-doll.csnet@csnet-relay.arpa> > Has anyone ever thought about the environmental impact that an > air-breathing x-atmos vehicle is likely to cause? ... we can wind up > with lots more nitrous oxide, nitric oxide, nitric acid,.. What > happens? We... reduce the ozone layer... I think it is fairly clear from other submission that this is the only real concern - the others seem to have been disposed of convincingly. > From: "Keith F. Lynch" <KFL@mit-mc.arpa> > This harks back to the anti-SST argument concerning NOx emissions > destroying the ozonosphere (which was vastly overblown). I agree - it is almost exactly the same argument. Since the scientific community has spent a huge amount of effort studying the upper atmosphere and devising various models of chemical transformations, the precise answer should be relatively easy to obtain. As I remember the latest reports on such research, the ozone layer is much more resilent that originally thought, so that there should be little difficulty. Moreover, existing SSTs are polluting the air far more than any space transportation system envisioned possibly could (exhausts weighted by frequency of flights). Clearly we are not suffering from ill effects (or they would have been reported by this time). > From: ucdavis!lll-crg!seismo!hao!ames!eugene@ucbvax.berkeley.edu > (Eugene Miya) > I think you raise a valid point and the Office of Technological > Accessment (OTA) should probably start such a study. ... Linking > this to SST hysteria (both pro and con) would do this no end of harm. First, I see no reason not to use previous relevant research. Second, given that the OTA seems to hate anything with the work "space" in it, I would strongly oppose getting them involved. > One must not be blinded by technological wonders. Nor by rabid environmentalism. It is this type of "problem making" that gives environmentalists (as opposed to conservationists) such a bad name. The space program is already suffering from inertia and lack of political support. While it is only prudent to take reasonable steps to minimize environmental impacts, it is silly to make a federal case (literally) out of something with such a low probability of being a fatal defect and such a high probability of being used to try and derail or delay any work on these programs for the indefinite future. Jim -------
al@vger.UUCP ( Informatix) (01/07/86)
> Since the > scientific community has spent a huge amount of effort studying the > upper atmosphere and devising various models of chemical > transformations, the precise answer should be relatively easy to > obtain. You have a lot more faith in those models and research than I do. The accuracy of weather prediction should give you an idea of how good such models really are - not very (maybe in a few decades ...).
dietz@SLB-DOLL.CSNET (Paul Dietz) (01/07/86)
>> Since the >> scientific community has spent a huge amount of effort studying the >> upper atmosphere and devising various models of chemical >> transformations, the precise answer should be relatively easy to >> obtain. >You have a lot more faith in those models and research than I do. The accuracy >of weather prediction should give you an idea of how good such models really >are - not very (maybe in a few decades ...). Actually, atmospheric chemical models and weather forecasting are not closely related. Current chemical models have proven inaccurate for this reason: there are thousands of chemical reactions going on in the atmosphere at various rates, and not all are well understood. In contrast, the physical processes in weather are reasonably well understood, but lack of fine grained measurements cripples forecasting. The January issue of Science 86 has an interesting article on new weather forecasting tools, primarily new sensing technologies. The most interesting uses two polar-orbiting satellites with CO2-laser radar to get global wind measurements. Meteorologists think these satellites alone will make 7-10 day forecasts as accurate as current 24-hour forecasts. Currently, wind measurements come from weather balloons.
eugene@ames.UUCP (Eugene Miya) (01/08/86)
[I tell myself that I'm going the read this group less.... oh well.] I did not see the original posting. > >> scientific community has spent a huge amount of effort studying the > >> upper atmosphere and devising various models of chemical > >> transformations, the precise answer should be relatively easy to > >> obtain. The atmosphere about 70,000 feet to 250,000 feet is relatively poorly understood. We have a building full of physicists and chemists working on a Cyber 205 around the clock spending $millions trying to understand the chemistry of this regime. > >You have a lot more faith in those models and research than I do. > >The accuracy > >of weather prediction should give you an idea of how good such models really > >are - not very (maybe in a few decades ...). > > Actually, atmospheric chemical models and weather forecasting are not > closely related. There is very little "chemical" with the weather: maybe ozone and small things. Weather is basically the state change of one compound (water). Very interesting. > Current chemical models have proven inaccurate > for this reason: there are thousands of chemical reactions going > on in the atmosphere at various rates, and not all are well understood. > In contrast, the physical processes in weather are reasonably well > understood, but lack of fine grained measurements cripples forecasting. This is correct. The people at NCAR could tell you better, but the spatial resolution of the GASP [Global AtmoSPheric circulation] model is about 2.5 degrees of latitude and longitude [over-simplication in my figures, but close enough 100 by 100 miles, which in turn barely fits on a Cray-1]. Consider 1 datapoint representing a 10,000 square mile area: say 1 temperature. Another problem is this the lack of adequate data from satellites: consider cloud cover. Typical weather images show cloud patterns over the NA continent [BTW: these were unknown before the space program]. But 70% of the world is covered by water which is NOT watched by satellites, so there is a major sampling problem. Nothing like running a weather program and then looking outside a window! Several radar-based instruments for measuring wind have been sent up on an experimental basis. > interesting uses two polar-orbiting satellites with CO2-laser radar > to get global wind measurements. There is an interesting story about CO2 measurements by a fellow at Scripps Inst. of Oceanography, but too long for this message. From the Rock of Ages Home for Retired Hackers: --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene emiya@ames-vmsb.ARPA