Reports

At Tonzi Floor from 2024-02-27 to 2024-03-36 we compared a new HygroVue sn E5736 with the old HMP45 sn W0510026 in preparation for continuing measurements of RH and T with the HygroVue.  The old HMP45 has been reading a little low in RH for several years.

Overall, the new HygroVue is better.  As to whether we should attempt to correct the old data I am uncertain.  Certainly the RH needs correction and this has already been implemented.  I think this report can act as a place holder and if someone needs more precise RH or T we can look at applying more complicated corrections.

Air Temperature looks pretty tight.  The old sensor has a few nighttime values a little lower than the new sensor.  Both sensors had ventilation fans.  I can only guess that the old sensor is just a little flaky.

Figure 1. Time series of air temperature.

Figure 2. Regression of air temperature.

Relative humidity is the reason this sensor is getting replaced.  The old sensor is reading a little low.  This was previously fixed by applying a regression to points about 85%, but I don't see an obvious break in the scatter during this inter-comparison. 

Figure 3. Time series of relative humidity.

Figure 4. Regression of relative humidity.