Denney Hall weather Station
data_description.txt
updated:  11/25/08 by JQD

The Department of Geography installed the original version of the Denney Hall rooftop weather station
in 1987.  It consisted of an array of sensors (temperature, relative humidity, wind speed, wind 
direction, rain gauge, and atmospheric pressure) from the WeatherMeasure Corporation hardwired via
underground cable to dial displays and strip chart recorders in Derby Hall.  With the renovation of
Derby Hall 1991, maintenance of the weather station was discontinued and did not resume until 1996.

In 2004 the dials and strip chart recorders were put away and we began recording sensor output on a
Campbell Scientific CR7 datalogger.  At the same time, we developed a suite of computer programs to
download the data, process and store it and display it on a web page.  Details regarding the format
of the archived data as well as the chronology of changes to the sensor array are given below.

The weather station, datalogger and the data visualization/archiving system are currently maintained
by Jim DeGrand (degrand.1@osu.edu).  

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April 8, 2004

The values in the archived data from the Denney Hall Weatherstation are the 1 minute reports from the
Campbell Scientific CR7 datalogger.  The data are in space delimited text files, 1 file per day.  The
file names are yyyy_0ddd.txt where yyyy is the year and ddd the julian day number.  The fields in the
data file are as follows:

1. Year (0004 = 2004, 0005 = 2005, etc)
2. Julian Day
3. Time (local EST/EDST). This was changed to GMT on December 9, 2005.
4. temperature (degreees C)
5. temperature (degrees F)
6. relative humidity
7. dewpoint temperature - calculated from T and RH as follows:

	Td = 237.7*alpha / (17.27-alpha)

	alpha = (17.27*Tc/(237.7+Tc) + log(RH/100))

	Tc=temperature (C) ; Td = dewpoint temperature (C) ; RH = relative humidity

8. dewpoint temperature (F)
9. pressure (millibars)
10. pressure (inches of mercury)
11. wind speed (meters per second)
12. wind speed (miles per hour)
13. wind pseed maximum (mps)
14. wind speed maximum (mph)
15. mean wind vector magnitude (mph)
16. wind direction (degrees from north)
17. standard deviation of the wind direction
18. precipitation (cm)
19. precipitation (inches)
20. saturation vapor pressure (from CS7 program 56)


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April 8, 2005

2nd barometer added to system.  Fields 21 and 22 are pressure from the Campbell CS105 sensor in 
millibars and inches of mercury, respectively

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December 9, 2005

Time (field 3) is now in GMT instead of local time.

Discontinued use of WeatherMeasure barometer.  Campbell cs105 barometer data are now in fields 9 and 10.

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June 1, 2006

Added output from Eppley pyronometer for downward solar radiation.  Output is in field 21; units are W/m^2.

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November 15, 2007

Added a Kipp & Zonen pyranometer and pyrgeometer outputs for solar down and longwave down in fields 22
and 23 respectively.  Units are W/m^2