may21-feb22 compare rain sensors
Comparing the sensors.
The orion rain sensor was replaced on
11may21 with a spare sent from orion. Rain data from 12may21
through 06feb22 was used to compare the rain sensor with the orion
tipping bucket. Both of these devices are installed on the orion
system located on the lidar lab roof. They are read
Data is read from the orion system every 15
seconds. It includes data from the rain sensor and the tipping
bucket. The rainToday(2) values was used to compare the 2
devices. The maximum value from each day was used as the daily
rainfall. Data from 12may21 through 06feb22 was used: 270 days. 5
days were excluded because of bad readings (mainly power outages).
This left us with 265 days of data.
The plots compare the results from
the 2 sensors (.ps) (.pdf)
- Top: over plot rain sensor and tipping bucket
- black is the rain sensor
- red is the tipping bucket
- the horizontal axis is date: yymmdd_hh
- the vertical axis is the daily rainfall in inches.
- The totals for each device (265 days) is also printed:
- rain sensor: 38.3 inches
- tipping bucket: 47.1
- This is a 25% difference (47.1-38.3)/38.3
- Middle: tipping bucket - rain sensor
- the daily difference is plotted vs date.
- most of the differences are > 0 ( the tipping bucket
value is > than the rain sensor value).
- Bottom: measured differences vs daily rainfall
- The vertical axis is the daily difference (Tipping bucket -
rainSensor) in inches of rain
- the horizontal axis is the daily rainfall (taken from the
- As the daily rainfall increases there is an increase in the
- 265 days of rainfall data was used to compare the values from
the rainfall sensor and the tipping bucket.
- The totals for the 265 days were:
- tipping bucket: 47.1 inches
- rain sensor :38.3 inches
- this is about a 25% difference.
- Most of the differences were positive (the tipping bucket
value was greater than the rain sensor).
- We saw similar differences when comparing the pre may21 rain
sensor with the tipping bucket (more info)
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