Reports

In fall 2020, we set up some comparison sensors on the SW tower for about 2 months.

• HMP155 sn R0360206 (reference sensor, brand new)
• 2 multi-globe thermometers (link to paper) -These sensors are from Joe's friend Atsushi Maruyama in Japan. The globe thermometers are three thermocouples in different size stainless steel spheres (~1mm – 7mm). Combining the three measurements should give actual air temperature without the need of a solar shield or ventilation.

All these sensors were connected to a CR1000 sn 4190. Data was measured every 10 seconds and 30-minute averages were recorded.

We compared these data to the tower AirT/RH data. The tower sensors were connected to the tower met datalogger. Data was measured every 10 seconds and 30-minute averages were recorded.

•     HMP45 sn W0730036 (AirT, RH)

On the left in the green lab clamps are 2 globe thermometers. On right right is a new HMP155 sensor to act as our reference sensor.

 

Figure 1. Time-series of air temperature. Fit looks good except HMP155 has slightly lower daily minimums.

Figure 2. Linear regression of air temperature. Tight fit without much noise.

Figure 3. Time-series of RH. Fit looks good except HMP155 has slightly higher daily  minimums.

Figure 4. Linear regression of RH. There is a slightly different slope when RH<20%, but that doesn't happen frequently so I feel ok ignoring it.

Figure 5. Time-series of calibrated RH. Seems like a reasonable calibration.