Release Notes

- Elevation data, used as input for post-processing of meteorological outputs from NWP models (Temperature, Atmospheric Pressure, and Relative humidity) and for calculation of CdTe PV spectral correction, was updated. Previously the main source of elevation data was SRTM3-v2, which had inaccuracies in some islands, coastal regions, and few deserted regions.
- The primary data source for the updated elevation data layer is SRTM-v4.1, which is an improvement over SRTM3-v2, but still, some issues remained.
- Many issues have been fixed by applying patches based on multiple data sources.

Data for Americas has been improved using the first complete year of GOES-R satellite imagery:

- better snow identification and processing in GHI and DNI calculation for period from 1 January 2018
- more info about the use of GOES-R satellite in Solargis model

- IFS forecast was updated with following changes
- Forecast update frequency is 6 hours (before it was  12 hours)
- Temporal resolution for first 48 hours was increased to 1 hour, hour 48-84 remains in 3 hourly resolution
- New region covering east Brazil

- Improved gap filling of meteorological parameters, and introduced minimum and maximum limits for parameters to avoid overshoots and other erroneous data cases

- CSV file header for TMY Pxx (75,90,95,99) data has been extended to include uncertainty values. The values include GHI/DNI model uncertainty, uncertainty because of inter-annual variability, and combined uncertainty. All uncertainty values are reported at P90 confidence (1.282 * SD).
- It is planned to include the uncertainty values also in PDF report issued along with the CSV files.

- De-biasing correction for TEMP data from CFSv2 model (applicable for period 2011 onward) was improved.
- Change in temperature values for period 2011 onward is mostly within ±0.5°C. The change in long-term average is even smaller. For details of TEMP post-processing method see https://solargis.com/docs/methodology/meteo-data/#post-processing-of-air-temperature-data

- Improved post-processing of night-time air temperature data from CFSv2 and MERRA-2 model outputs. Updated lapse rate used for spatial downscaling of TEMP data to 1km resolution.
- This change affects Solargis time series: historical, recent, nowcast and forecast.
- All regions are affected but most significant corrections are seen in the coasts of California, Namibia and Chile, western Canada and Yakutia (Russia).

- Time series data from GOES-West satellite region, covering Northwest USA, West Canada and Hawaii were re-analyzed. The update affects period between January and October 2018.

- Terrain shading model has been improved in the calculation of diffuse irradiance. This change affects Solargis time series data: historical, recent, nowcast and forecast.

- Solar radiation calculation scheme has been improved for Americas, Middle East, Asia and Pacific by implementing better management of raw satellite data. The values of GHI, DNI, DIF, GTI and PVOUT parameters are affected by new version of the Solargis model only in rare cases related to a specific segment geometry.
- New parameters have been introduced (available via API and FTP): PV Module Temperature (TMOD) and Precipitation Rate (PREC). TMOD is useful for evaluation of daytime temperature of PV modules, and for calculation of temperature-corrected performance ratio. PREC can be used for improved understanding of soiling and cleaning of PV modules.
- Nowcasting service was extended to Australia, Morocco and Canary Islands
- Geographical coverage of forecasting service based on postprocessing of the IFS outputs (the model operated by ECMWF) was extended to Northeast China, Turkey, Jordan, New Caledonia, Kenya, Morocco and Canary Islands.