[BLDG-SIM] (Near) Real-Time Weather Data Archive now available

Drury.Crawley at EE.DOE.GOV Drury.Crawley at EE.DOE.GOV
Fri May 30 13:52:52 PDT 2003

DOE is pleased to announce that a weather data archive with very recent
data (near real-time) for more than 1600 locations in the US and another
2500 locations around the world is now available on the web:


(Or through the real-time weather data link on the right hand side of the
EnergyPlus web site:  www.energyplus.gov)


In 1998, the Gas Technology Institute (formerly the Gas Research Institute)
created a real-time (very recent data) weather data archive for 245
locations in the United States.  After the original funding ended in 1999,
GTI was no longer able to maintain the weather data archive.

In 2001, DOE began investigating ways to restart and extend the database to
other locations in the US and throughout the world.  In 2002, the National
Renewable Energy Laboratory (NREL) began collecting hourly data for DOE as
it was reported the same day from the US National Weather Service (NWS) ftp
site for more than 4100 locations throughout the world.  This new
'real-time' weather data archive was developed by, and is hosted and
maintained by NREL.   Most locations have data which begins in early 2002.

GTI and its subcontractors, Mason-Grant Company and Rocket  Science Inc,
graciously agreed to donate the existing data archive and allowed DOE to
incorporate that data into the new database. The 245 US locations
originally in the GTI data archive often have data from 1998 through today.
But there are often significant gaps in the data.

Data Available

Because of network interruptions or missing data on the NWS ftp site, the
weather data archive does have gaps of hours to days.  If missing data is
less than 48 hours in length, the web site can interpolate the data for the
user. (Currently only wet bulb and dry bulb temperatures are interpolated.)
When data are missing, the data are broken into separate files.

The following data are available:

1. Local Date and Time, MM/DD/YYYY HH:MM
2. Greenwich Mean Time, MM/DD/YYYY HH:MM
3. Dry Bulb Temperature, tenths of degree Celsius
4. Wet Bulb Temperature, tenths of degree Celsius
5. Wind Direction, degrees (0º = North)
6. Wind Speed, tenths of meters per second
7. Wind Gusts, tenths of meters per second
8. Wind Variability Range, degrees
9. Altimeter, hundreds of pascals
10. Visibility, tenths of kilometers
11. Weather Description, MI, BC, PR, TS, BL, SH, DR, F
12. Weather Precipitation, DZ, RA, SN, SG, IC, PL, GR, GS, UP
13. Weather Observation, BR, FG, FU, VA, SA, HZ, PY, DU
14. Weather Other, SQ, SS, DS, PO, FC
15. Cloud Cover Level 1, identifier, height in hundreds of feet
16. Cloud Cover Level 2, identifier, height in hundreds of feet
17. Cloud Cover Level 3, identifier, height in hundreds of feet
18. Sea Level Pressure, hundreds of pascals

NOTE--There are NO SOLAR DATA reported through the NWS ftp site.

Users can request any amount of data--from a single day to the entire
available period of record (1998-May 2003 for the 245 US locations,
2002-May 2003 for most locations).  Data are usually available within a
week or so after they are reported on the NWS ftp site and updated
continually (It takes a long time to process 4100 locations!).  Data are
emailed directly to the user, usually within minutes.

Output formats include comma-separated values (CSV) and IWEC (ASHRAE's
International Weather for Energy Calculations).  Both are documented in the
manual available on the web site.

We hope that you find the archive useful and we welcome feedback!

Dru Crawley

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