1. Addition of PAR values between Nov 24, 1997 @ 11:30 and Jan 13, 1998 @ 12:00. This was done at the request of Thomas Nylen.
On June 1, 2000, the 1999-2000 data was posted. In the process, Denise Steigerwald changed thelayout of the files so that they were sorted by category (ait temperatures, humidity, radiation,wind etc.) rather than by year. Files containing monthly and daily averages were generated andminor adjustments were made to the metadata.
On June 1, 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 whichwas used initially). The error became quite large for very cold temperatures (the correction couldgrow 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 99.99and 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.