Pilots are only interested in the pressure to the nearest hPa, the altimeter Kollsman window only has 4 digits, hence 1013 hPa would be fine. For all practical purposes we can forget about numbers after the decimal point.
> [Original Message] > From: G. Stanley Doore <[EMAIL PROTECTED]> > To: U.S. Metric Association <[EMAIL PROTECTED]> > Date: 08/9/03 15:23:20 > Subject: [USMA:26908] Re: Non-SI metric units > > The issue here is the user or consumer. Pilots have training in meteorology > to get their ticket and so they are taught to read coded wx fcsts and obs > including pressure without a decimal point. > > Internal to computer systems for most of the last century, no decimal was > included in transmissions. This was particularly true when teletype was > used. The same is true today depending of the user. The decimal point is > assumed according to communication protocols, display units and user. The > public uses decimal points whereas automated systems mostly don't include > them. > > This is and has been common practice worldwide for a least a century. > > Stan Doore > > ----- Original Message ----- > From: "Joseph B. Reid" <[EMAIL PROTECTED]> > To: "U.S. Metric Association" <[EMAIL PROTECTED]> > Sent: Monday, September 08, 2003 11:11 AM > Subject: [USMA:26904] Re: Non-SI metric units > > > > Stan Doer wrote in USMA 26895: > > > > >Atmospheric pressure is observed (measured) to the nearest tenth of a > mbar > > >or a tenth of a hPa.. That's five digits. Standard atmospheric pressure > is > > >1013.25 mbar or 101.325 kPa or 1013.25 hPa. > > > > > >Hope this clarifies. > > > > > >Stan Doore > > > > > > > This may seem to be contradictory, or at least, paradoxal. The > > explanation is that 1013.25 hPa would be transmitted on the > > aeronauical weather network simply as 01325, while 995.67 hPa would > > be transmitted as 99657. Since these are transmitted in a standard > > format there is no need of explanation or decimal point. > > > > > > -- > > Joseph B. Reid > > 17 Glebe Road West > > Toronto M5P 1C8 Telephone 416-486-6071 > > > > --- Michael Payne --- [EMAIL PROTECTED] --- EarthLink: The #1 provider of the Real Internet.
