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| GHI | Global horizontal irradiation | kWh/m2 | Average annual, monthly or daily sum of global horizontal irradiation. |
| DIF | Diffuse horizontal irradiation | Average yearly, monthly or daily sum of diffuse horizontal irradiation. | |
| DNI | Direct normal irradiation | kWh/m2 | Average yearly, monthly or daily sum of direct normal irradiation. |
| GTI | Global tilted irradiation | kWh/m2 | Average annual, monthly or daily sum of global horizontal irradiation. |
| TEMP | Air temperature at 2 meters | °C / °F | Average yearly, monthly and daily air temperature at 2 m above ground. |
| PVOUT | PV cSi yield | kWh | Yearly and monthly average values of photovoltaic electricity (AC) delivered by the total installed capacity of a PV system. |
| WS | Wind speed m/s at 10 m above ground | m/s | Average yearly, monthly and daily wind speed at 10 m above ground. |
| RH | Relative humidity at 2m above ground | % | Average yearly or monthly relative humidity at 2 m above ground. |
| PWAT | Precipitable water | kg/m2 | Precipitable water is the depth of water vapour in a column of the atmosphere, if all the water in that column were precipitated as rain. It indicates the amount of moisture above ground. |
| PREC | Precipitation (rainfall) | mm | Average yearly and monthly sums of precipitation. |
| SNOWD | Snow days | days | Snow days are calculated as days with snow water depth equivalent to or higher than 5 mm. |
| ALB | Surface albedo | Fraction of solar irradiance reflected by surface. Ratio of upwelling to downwelling (GHI) radiative fluxes at the surface. | |
| CDD | Cooling degree days | degree days | Quantifies energy demand needed to cool a building. "Cooling degree days" are a measure of how much (in degrees), and for how long (in days), outside air temperature was higher than a specific base daily average temperature (18°C). Yearly and monthly values are aggregated from daily values. |
| HDD | Heating degree days | degree days | Quantifies energy demand needed to heat a building. "Heating degree days" are a measure of how much (in degrees), and for how long (in days), outside air temperature was lower than a specific base daily average temperature (18°C). Yearly and monthly values are aggregated from daily values. |
| GHI_VAR_LONG | Long-term variability of Global horizontal irradiation | % | The standard deviation of the yearly time series of GHI. |
| GHI_VAR_SHORT | Short-term variability of Global horizontal irradiation | The yearly average count of GHI ramps exceeding the 400 W/m2 threshold, analyzed from Solargis GHI Time Series. |
|
| CORR | Corrosion degradation rate | % | Degradation effect in PV modules, primarily driven by temperature and humidity. |
| TMOD_AMP50 | Daily module temperature amplitude higher than 50 °C | days | The average number of days in a year with daily PV module temperature amplitude higher than 50 °C. |
| WG p99 | Wind gust p99 | m/s | The 99th percentile of wind gusts at 10 m height above ground calculated from the ERA5 hourly dataset from 2001 to 2020, averaged to provide a yearly number. |
| UVA | Ultraviolet A radiation | kWh/m2 | Average annual UVA radiation. |
| UVB | Ultraviolet B radiation | kWh/m2 | Average annual UVB radiation. |
| ELE | Elevation | ||
| SLO | Slope | ||
| AZIM | Azimuth | ||
| POPUL | Population density | ||
| LANDC | Land cover | ||
| D2G | Ratio of diffuse to global irradiation | Ratio of diffuse horizontal irradiation and global horizontal irradiation (DIF/GHI). | |
| OPTA | Optimum tilt of PV modules | ||
| TLEO | Lowest expected operating temperature | °C / °F | Mean of annual extreme low temperatures according to IEC 62738. |
| THEO | Highest expected operating temperature | °C / °F | Average of the highest recorded air temperatures over 20 years at the site according to IEC 62738. |
|
Horizon, Sun path, Day length, Solar zenith angle |
| Spatial resolution | Data parameters |
|---|---|
|
3 arc-seconds, approx. 90m x 90m 9 arc-seconds, approx. 250m x 250m 10 arc-seconds, approx. 300m x 300m 30 arc-seconds, approx. 1 km x 1 km 2 arc-minutes, approx. 4 km x 4 km 0.1 degree, approx. 11 km x 11 km 0.25 degree, approx. 28 km x 28 km |
ELE, SLO, AZIM GHI, DIF, DNI, GTI, D2G, DNI_SEASON, GHI_SEASON LANDC PVOUT, TEMP, TLEO, THEO, ALBEDO, HDD, CDD, POPUL OPTA, GHI_VAR_LONG, GHI_VAR_SHORT, CORR, TMOD_AMP50 PREC, SNOWD WS, WG, RH, PWAT, UVA, UVB |
| Spatial resolution | Data parameters |
|---|---|
|
3 arc-seconds, approx. 90m x 90m 30 arc-seconds, approx. 1 km x 1 km 2 arc-minutes, approx. 4 km x 4km 0.1 degree, approx. 11 km x 11 km 0.25 degree, approx. 28 km x 28 km |
PVOUT, Horizon TEMP GHI, DNI SNOWD PWAT |
Time representation of various parameters depends on the input sources and models behind them. With few exceptions, it spans from the 1990s/2000s to the last year. Depending on the region, the long-term averages are calculated for a period from 1994/1999/2005/2007/2018 to 2024. Please, refer to the map above for the specific start year.
The long-term averages of the other meteorological parameters are calculated for a period 1994-2024 globally.
Ground albedo data represents the long-term average for a period 2006-2015.
