Here Comes The Sun

You might have noticed a couple new readings in the “Current Conditions” section of our home page. I’ve installed 2 new sensors on our main weather station, a Davis Vantage Pro2, to measure output from the Sun.

One sensor reads a narrow band of ultraviolet (UV) radiation. The 290 – 390 nm spectrum of the sun’s shortwave energy particularly affects human health. Readings are translated into a universal UV index (1 – 16 scale).

The other sensor measures broad spectrum solar radiation (a.k.a. “solar irradiance”, “solar insolation”) between 300 – 1100 nm. It’s output scale is 0 – 1800 Watts per meter squared (W/m2). This is useful for solar energy management & approximating cloud cover / ambient light. You may wonder “can’t I just look out a window?” If you are in Marquette, yes. If you are elsewhere, no.

In addition, these readings are being archived on the Weather History page for future reference. People come from all over the world to look up historical conditions in Marquette. Some of them have summer homes here. Others are researching a potential move. Still others are simply curious, perhaps, about friends, family, future trips, or an unknown place.

Real-time solar irradiance data is also being transmitted to NOAA and other governmental and academic institutions for purposes of forecasting and research. As far as I know, we are only the 2nd station in the U.P. that broadcasts this data via CWOP (Citizen Weather Observer Program). The other is in the Keweenaw Peninsula. The only other weather station on any network, that I’m aware of, to report solar output in Upper Michigan for official purposes is the Climate Research Network station in Chatham.

The UV index will only be displayed in Current Conditions during the warmer months running, roughly, April/May to October/November. Year round it can be found on the Weather History page in the daily/monthly/yearly tables by clicking the “Solar” tab. Currently, only the daily table is operational with solar data. I’m still in the process of adding a tab to the monthly and yearly tables.

You”ll also see 24-hour graphs on the History page for UV (warm months only) and solar radiation. The latter, in particular, is an easy way to visualize cloud & precipitation development during daylight hours. Once you get a handle on the scale for any given time of year, you can easily spot when clouds appear or lighten/thicken.

It’s my hope that this enhancement further informs and enriches you as well as local community members who may consume our data or its end products without even knowing it (forecasts / various apps / search engines).


Acknowledgement: Thank you to Ryan Wilhour at Scaled Instruments for his outstanding customer service. Originally I intended only to order the solar radiation sensor but received the UV sensor by mistake. Suffice to say, Ryan made it right, allowing me to obtain both sensors at a considerable discount. If you are a weather station owner or prospective owner, you cannot beat Ryan’s prices and service. I’ve used him for years now. He’s never disappointed.

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