First off, it's clear that you must be reporting your pressures in
values that are corrected to sea level values (i.e., not the pressure
measured at the station elevation, which would be much lower). See
http://www.ofcm.noaa.gov/fmh-1/fmh1.htm
I suspect that your recollection of the "observed/estimated median"
pressure is somewhat high, and that what you are seeing is the normal
seasonal variation of barometric pressure over the SW United States.
I couldn't find good average data for Santa Fe, but the average
sea-level barometric pressure for Albuquerque from 1951 to 1988 was
1014 hPa (see http://www.worldclimate.com/cgi-bin/data.pl?ref=N35W106+4102+72365W
and recognize that 1 hPa = 1 mbar). There is a clear variation in the
average monthly barometric pressure over the course of the year,
however, with the pressure being highest over the winter months (
average = 1019.5 hPa in Jan and Feb, and lowest in the early summer
(average = 1009.9 hPa in Apr-Jun). The average pressure for this time
of year is around 1014 hPa. Note that this is almost exactly the
"defined" average value for mean sea-level atmospheric pressure of
1013.25 hPa. (I say "defined" because the *actual* value is probably
more like 1011 hPa - see Trenberth KE, 1981, Seasonal variations in
global sea-level pressure and the total mass of the atmosphere. J.
Geophysical Research - Oceans and Atmospheres, v86, pp5238-46.) An
average pressure of 1023h Pa seems suspiciously high to me.
There is a possibility that you are seeing something real, and that
the average pressure for the past few years *has* been higher than the
long-term average. The western US has been in the grips of a major
drought for several years, and such a climate pattern is typically
associated with persistent higher-than-average barometric pressure
over the western US. A breakdown of this atmospheric pattern might
accompany the end of the drought conditions, but as far as I know, the
drought is continuing.
The NOAA National Climatic Data Center has a wealth of historical
climate data that can be downloaded for free (or a very small nominal
charge, like $2.00-3.00) at
http://www5.ncdc.noaa.gov/cgi-bin/script/webcat.pl?action=ALL. In
particular, check out the "Local Climatological Data, Edited". I did
a quick check of what was available for NM, and it looks like the ABQ
airport has historical pressure data, but the data are either funky or
missing for the past several years :-(
The Weather Underground web site for NM
(http://www.weatherunderground.com/US/NM/) has links to a number of
privately operated met sites around the state. (Select a location
from the page at the above link, and then scroll down to find the
table of "Personal Weather Stations".) Many of these stations have
historical barometric pressure data that you can display by month. I
would, however, be cautious about the quality of these data, as there
is no guarantee that the corrections to sea-level values have been
done correctly! Trends are probably ok, but the absolute values are
probably not directly comparable.
Another resource you might check is the Citizen Weather Observer
Program (CWOP) at http://www.wxqa.com/stations.html, but I don't think
these stations maintain a very long on-line record of historical
observations. |
