Story by Pete Boulay,
Assistant State Climatologist, Minnesota State Climate Office
Dr. Don Baker established the St. Paul Campus Climate Observatory in late September 1960 and it became an official National Weather Service Cooperative site in 1961. Don was essentially the godfather of the station and was its manager for the next 30 years. Soil Scientist Dave Ruschy kept the station running after Don retired.
Dr. Baker employed an army of grad students to tend to the many observations at the station, sometimes taking up to an hour to record all the measurements. In addition to air temperature, there was ground temperature, solar radiation and pan evaporation to name a few.
Soil temperature readings are made via thermocouples from 1 cm to 12.8 meters. There is a time lag for the surface temperature to penetrate the soil. This time lag is about 30-60 minutes for the 1 cm depth, to about a year around 10.6 meters. The soil temperature readings recorded down to 12.8 meters (42 feet) are nearly unique in the United States.
1960s
There have been other unique measurements as well in the past such as the weighing lysimeter in the agriculture plot outside the fence. This is a large tank filled with soil on a very sensitive truck scale and can be used to measure the actual evapotranspiration. There were also sensors to measure Gamma Radiation at the station too. One could detect droplets of rain that were too small to measure any other way.
Over the years the station has slowly been modernized. The liquid in glass measurements in the Cotton Region Shelter were discontinued in the early 1990s in favor of the MMTS (Maximum Minimum Temperature Shelter) Pan evaporation measurements began on May 23, 1972. This is an instrument that looks like a kiddie swimming pool where the level of the water level is measured.
Over in the southeast part of the plot the 8 inch Standard Rain Gage (SRG) is still in use as the official precipitation for the St. Paul Campus. This gauge has been in roughly the same spot over the past sixty years. Just to the north of the SRG is the frost tube. Frost depth measurements have been recorded since the 1960’s. Near the steps of the block house is an Eppley Radiometer to measure the incoming solar radiation. This is an old instrument that is being used to compare the more modern radiometers.
A new station that was installed in 2019 is the Hennepin Mesonet tower with wind speed and direction at the standard height that the National Weather Service uses. It is 10 meters high as the international standard.
Many an observer walked out there in some of the worst weather conditions you can think of.
The twin snowstorms in January 20-21, 1982 (17.4 inches MSP) and Jan 22-23, 1982 (20.0 inches MSP) were a special challenge at the weather station.
At about noon on January 22nd 1982 the University closed for the first time due to weather since 1965. Dave Ruschy remained at his post as long as he could and the daily observations were made at 4pm instead of the usual 5pm observation. This was one of the few times that the observation at the weather station was not taken at the usual time. Even a power outage caused by the Har Mar tornado of June 14, 1981 didn't completely shut the station down. Mark Seeley was taking the observations that day and hid in the blockhouse listening to the “train-like” sounds of the tornado passing by to the north.
The biggest challenge the weather station had over 50 years (besides the time it was vandalized on July 28, 1990) was in Spring of 1965 when the deep snow pack melted and water flooded the station. There was water 4 feet deep in the blockhouse. The arriving observer found water coming out of the keyhole when he showed up to take the observations. It took a week or two before all the observations were back in order. It may be weathered a bit but the observatory continues to operate to this day.
