SGP/TWR/C1 - West RH Probe Replacement

On 4-5 November 1997, the Qualimetrics RH probes were removed from the west
elevator 25 and 60 meter levels and replaced with Vaisala probes.  The
Vaisala probes had to be inserted upside down in the Qualimetrics
aspirators to make them fit.  Data during the period above is incorrect.
The west temperature probes appeared to need recalibration, so that was
done on 5 November.  Little improvement in the comparison of west and
southeast carriage temperatures can be detected in the data after 5
November.  RH comparisons show that the west and southeast side Vaisala
probes agree within 1% normally, with only a very occasional 3% to 4%
difference (when RH is greater than 90%).  West side temperatures are normally
greater in the daytime especially, an indication that the aspiration rate in
the west side aspirators is marginal, as I reported when they were installed 5
years ago.  The west side metal aspirators also have more thermal mass than the
plastic southeast aspirators; the combination of this with the lower aspiration
rate causes the west side temperatures to not drop as rapidly as those
measured on the southeast side when the temperature is decreasing.  The west
side temperatures are often 0.2 to 0.6 degrees higher than the southeast
side during the midday.  Obviously, when the temperature differences are large,
the RH tends to be slightly smaller on the west side.

The vapor pressure differences between the west and southeast sides are very
small, 0.03 kPa or less, usually much less, a result that should make the
WVIOP community happy.

• Vapor Pressure (kiloPascals)(vap_pres)
• Relative Humidity (hybrid-b grid)(rh)

• Relative Humidity (hybrid-b grid)(rh)
• Vapor Pressure (kiloPascals)(vap_pres)
• Standard deviation of vapor pressure(sd_vap_pres)
• Standard Deviation of Relative Humidity(sd_rh)

• Vapor Pressure (kiloPascals)(vap_pres)
• Relative Humidity (hybrid-b grid)(rh)

• Minimum Relative Humidity(min_rh)
• Daily minimum vapor pressure(min_vap_pres)
• Daily maximum relative humidity(max_rh)
• Maximum Vapor Pressure(max_vap_pres)

• Daily minimum vapor pressure(min_vap_pres)
• Minimum Relative Humidity(min_rh)
• Maximum Vapor Pressure(max_vap_pres)
• Daily maximum relative humidity(max_rh)

• Relative Humidity (hybrid-b grid)(rh)
• Standard deviation of vapor pressure(sd_vap_pres)
• Vapor Pressure (kiloPascals)(vap_pres)
• Standard Deviation of Relative Humidity(sd_rh)