In that list, the two logical choices are millibars (same as hectopascals) and kilopascals. In it's metric option, the National Weather Service uses millibars(hectopascals) as do many other countries (gives numbers around 1000) while Environment Canada uses kilopascals (numbers around 100). The use of kilopascals is in line with the rule (recommendation) of 1000, prefixes which are multiples of 10³ and numbers in range 1-1000. Hectopascals are used because the numbers agree with millibars which were formerly used. The others are obsolete and/or non-metric.
>________________________________ > From: "[email protected]" <[email protected]> >To: U.S. Metric Association <[email protected]> >Sent: Monday, June 30, 2014 1:51 AM >Subject: [USMA:54077] Pressure Unit > > > > >While customizing my http://www.TimeAndDate.com preferences today, I became >rather curious about why so many options are available for Pressure Unit. I >see on the list millabar, Hg, Pa, bars, mmHg, psi, atm and kPa. Now, since I >know less about Pressure Units than most of you, I am hoping someone would >jump in and recommend the most appropriate one. (I already know that none of >you will recommend psi.) Thanks in advance. See attached picture. I hope none >of your computers have trouble opening a png picture format. >David Pearl www.MetricPioneer.com 503-428-4917 > >
