LAB

Sunshine & Temperature

Exploring the relationship between surface solar radiation (sunshine) and surface air temperature.

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Incoming sunshine delivers energy to the surface. More sunshine generally supports higher temperatures, but the relationship is complex. Clouds, aerosols, albedo (ice/snow reflection), elevation, latitude, and ocean/land effects all play major roles.

Select Station Pair

Raw + Adjusted loaded

IMPORTANT CAVEATS

Temperature Data

Comparison

Solar Measure

Pyranometer (MJ/m²) — total incoming solar energy at the surface per month (direct + diffuse), from ERA5 shortwave_radiation_sum. This is what a pyranometer measures: global horizontal irradiance.

Sunshine hours — hours of "bright" sunshine per month (irradiance above ~120 W/m²), from ERA5 sunshine_duration. Analogous to a Campbell-Stokes recorder. Does not capture diffuse radiation on overcast days.

Raw is unadjusted monthly GHCN temperature from Klymot; Adjusted is homogenized. Solar data loaded from data/sunshine-qc.json.

Sunshine Lag

0 mo

Time Axis

Visualizations

Monthly pairs

Time Series

Aligned observations

Scatter: Sunshine vs Temperature

Correlation Analysis

Pearson r

0.72

r² (explained variance)

0.52

p-value (approx)

<0.001

Contribution Score

Strong positive contribution (r = 0.72)

Sunshine explains a meaningful portion of temperature variance at this location. Other factors (clouds, circulation, etc.) account for the remainder.

Sources & References

Temperature: Klymot station CSVs derived from GHCN-Monthly v4 Raw and Adjusted records. GHCNm is the Global Historical Climatology Network Monthly temperature dataset; Klymot uses station records as the primary climate observation source. Menne et al., 2018 DOI.

Homogenization: Adjusted records follow the GHCN processing lineage, including pairwise homogeneity methods for non-climatic shifts. Menne & Williams, 2009 DOI.

Pyranometer / Shortwave radiation: Monthly totals of shortwave_radiation_sum from the Open-Meteo Historical Weather API (ERA5 reanalysis). ERA5 derives surface downwelling shortwave radiation from the ECMWF atmospheric model; it represents global horizontal irradiance — the same physical quantity measured by a pyranometer — but is a gridded model estimate rather than a station instrument record. Open-Meteo documentation. ERA5 dataset.

Sunshine hours: Monthly totals of sunshine_duration from the same ERA5/Open-Meteo source. Counts hours where surface solar irradiance exceeds approximately 120 W/m², analogous to a Campbell-Stokes sunshine recorder. Both solar variables are fetched by scripts/fetch_sunshine.py and stored in data/sunshine-qc.json.

This is a neutral exploration tool. Correlation does not imply causation; circulation, clouds, albedo, elevation, land/sea effects, and station exposure can influence both variables.