Snow Rules!

Enhanced Snow and Precipitation Monitoring within Minnesota Portions of Watersheds Draining to Lake Superior

Minnesota’s Lake Superior Coastal Program

Hwy 1 Transect

June 2004 average diurnal behviour

hours of possible solar 'contamination' highlighted

The thermochrons mounted on power poles were placed on the north sides using a compass for guidance. In that way for much of the time the device is not exposed directly to solar radiation. However, in months 'summerward' of the equinoxes the sun rises and sets somewhat to the north of due east/west. Before the sun passes into the hemisphere south of the east-west plane it can attain an altitude of nearly 30 degrees above the horizon. At such elevations, the thermochrons may be exposed to direct sunlight. For the geographical location of Hwy 1 the hours of 6 and 18 CST have the greatest potential for such 'contamination' In hours either side of those hours the sun is either closer to the horizon or is closer to passing 'in back of the pole'. The following graphs depict the average June 2004 temperatures at each of the devices over the course of a typical 24-hour day. The hours discussed above are colored orange in the graphs to facilitate examination. There seems to be little morning solar effect but at several locations there appears to be a 'spike' in temperature near 18p.

Images are in order from Lake Superior to inland.

'lakeward' of Hwy 61

Hwy 61 to Isabella

Snow Rules! thermochron page
Snow Rules! main page
State Climatology Office, DNR - Waters, 2004