DOI: 10.5281/zenodo.15121982
title: Solar irradiance measurements from Automatic Weather Station (AWS) at Freiburg – Chemiehochhaus (FRCHEM) from 2021-01-01 to 2021-12-31 [L2]

description: Quality controlled and gap-filled continuous solar irradiance measurements from the urban rooftop weather station at Freiburg-Chemiehochhaus (FRCHEM, 7.8486ºE, 48.0011ºN, 323.5 m) operated 2 m above roof level. Solar irradiance is measured using a ventilated pyranometer CM21 (Kipp & Zonen, Delft, Netherlands). The pyranometer was factory calibrated at Kipp & Zonen on 2018-01-10.



Quality controlled above-canopy solar irradiance data are available and aggregated at 10min, 30min, hourly, daily, monthly and yearly resolution for the year 2021. Values are averages during the periods shown.

Solar irradiance in this dataset is equal "global irradiance" or "global hemispherical irrandiance" and does not distinguish between direct and diffuse irradiance.

Modeled extraterrestrial irradiance (based on the NOAA General Solar Position Calculations of the NOAA Global Monitoring Division and considering the Earth's elliptical orbit) is provided for comparison, along with the ratio of solar irradiance to extraterrestrial  irradiance at 10min, 30min, hourly, daily, monthly and yearly resolution. Extraterrestrial irradiance is average of period show.

Data in the mid-morning on clear-sky days in summer can be impacted for a few minutes by a guy-wire of the mast, slightly reducing readings. Data from affected periods are not removed. 

Number of hours with solar irradiance >5 W/m2 (daylight hours) and > 120 W/m2 (sometimes used as threshold for "sun hours") provided on daily, monthly, and annual scale.

Number of days with solar irradiance >5 W/m2 (quality check) and > 120 W/m2 ("sun hours") provided on monthly, and annual scale.

Detailed information on gap-filled data is provided.

Note: All times are provided in UTC, not local time.


For more details read `FRCHEM_2021_SolarIrradiance_MetaData.txt`.

Version 1.1



displays times according to ISO 8610 to unambiguously identify that all times are given in UTC. Further, the column headers for the time periods have been changed to "From" and "To" to indicate the start and end of the aggregation periods.
description: COPYRIGHT



Creative Commons Attribution 4.0 International. Copyright Albert-Ludwigs-Universität Freiburg, Professur für Umweltmeteorologie, Werthmannstrasse 10, Freiburg, Germany.


CREATOR

This work is owned by the University of Freiburg.

ATTRIBUTION

The [creation and] curation of this work has been supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 855005) and the University of Freiburg.

DISCLAIMER

The use of the work is at the user's own risk. The authors, the University of Freiburg, and/or the European Research Council accept no liability for material or non-material damage arising from the use or non-use or from the use of incorrect or incomplete information in this work. The authors, the University of Freiburg and/or the European Research Council are not responsible for any use that may be made of the information in this work. The legal provisions remain unaffected.