On September 3, 1999, at the request of Thomas Nylen, the data manager did some fine-tuning
of the data. This included:
1. Deletion of flags for ice temperature measurements from Nov 20, 1993 @ 16:30 to Dec
24, 1993 @ 14:30. Instruments were not installed during this time;
2. Removal and flagging of WDir values for measurements taken between Nov 23, 1994 @
10:20 and Jan 23, 1995 @ 13:20 where WSpd = 0. Since the wind speed values during
this time were flagged as bad, the original database query probably did not flag the WDir
data when WSpd =0.
In May 2000, the 1999-2000 data was posted. In the process, Denise Steigerwald changed the
layout of the files so that they were sorted by category (air temperatures, humidity, radiation,
wind etc.) rather than by year. Files containing monthly and daily averages were generated and
minor adjustments were made to the metadata.
On May 30, 2000, relative humidity (RH) values were corrected for a systematic error in the
measurement created by an instrument manufacturer error. All RH data with air temperatures
below freezing were corrected using the vapor pressure over ice (rather than over water which
was used initially). The error became quite large for very cold temperatures (the correction could
grow to around 30%). The formula used for the correction was:
RH_corr=RH_orig/((A*temp*temp)+(B*temp)+C)
where
RH_corr = corrected relative humidity
RH_orig = original relative humidity
temp = air temperature
A = 4.165E-5
B = 9.7E-3
C = 1.0
For example, with an air temperature of -2.3 and RH_orig of 50.6, the RH_corr will be 51.7.
Records that showed corrected RH values greater than or equal to 100 were changed to 99.99
and flagged.
In June 2000, summary files were added to the web containing daily and monthly statistics.
These were generated by creating "views" of daily and monthly means, minimums, maximums
and counts of the records represented in the Oracle database's meteorology tables.
On May 7, 2003, SwRadIn and SwRadOut values between 11/20/1993 4:30:00 PM and
11/23/1994 8:00:00 AM flagged as questionable because the values are significantly lower than
the other stations during the same time period. It appears the pyranometers were either tilted or
installed improperly. Also SwRadIn and SwRadOut values between 11/25/1997 @ 1445 and
01/10/1998 1430 because the wrong multiplier was used. The SwRadIn values were divided by
109.29 and multiplied by 115.61 and the SwRadOut were divided by 108.7 and multiplied by
116.41.
On June 29, 2004, wind direction between 11/20/1993 16:30 to 11/27/1995 15:00 was flagged
because the data is about +25 degrees off from the true direction. This was determined by
comparing the daily wind direciton over the entire 10 years of record. Additionally, between
11/27/1995 15:30 to 11/25/1997 13:30, the wind direction data was flagged because it is about -
10 degrees off from the true direction.
