Bird spike kit and solar radiation data
With the bird spike kit installed, dips in the pyranometer data may occur during clear sky conditions. This is caused by the wire shadows that move across the pyranometer sensor throughout the day on sunny days. The wire shadow effects are negligible (<1% error) on a diffuse day with continuous cloud cover and should be less than 6% error in total daily solar radiation on a clear sky day.
Correcting for wire shadow effects is impractical because different cloud cover, time of day, time of year, and location will cause the shadows to vary.
ClimaVue 50 G2 solar radiation data with and without bird spike kit provides solar radiation data of ClimaVue 50 G2s with and without bird spike kits. On 3/9/2019, ClimaVue 50 G2s with bird spike kits installed show dips in solar radiation data. The bird spike kit did not affect the solar radiation data on completely cloudy days, when no wire shadows are present (see 3/8/2019 in ClimaVue 50 G2 solar radiation data with and without bird spike kit).
On a mostly clear sky day, the error caused by the bird spike kit was a decrease in total solar radiation by 3.0% and 4.7% for two ClimaVue 50 G2 pyranometer sensors. On a cloudy day, the error caused by the bird spike kit was less than 1%. On a clear sky day, the error caused by the bird spike kit was a decrease in total solar radiation by 2.6% and 5.7%. The error was estimated by summing the daily solar radiation of ClimaVue 50 G2s with bird spike kit (experimental) and without bird spike kit (control) and calculating the percent error. Data was collected at 5 minute intervals.
Without summing daily solar radiation, the percent error when the pyranometer dips are most drastic resulted in a decrease of 13 to 17% solar radiation (clear sky day). The most dramatic dips occurred on 3/9/2019 and resulted in a decrease of 83 to 113 W/m2 (ClimaVue 50 G2 solar radiation data for 3/9/2019).
