In case of solar and PV time series (GHI, DNI, DIF, GTI, PVOUT) we use satellite data since history up to present moment plus 4-5 hours ahead. This include historical (archived) data, operational data, real-time and nowcasting data. Historical data spans up to last completed calendar month and can be considered as "definitive". Data in current calendar month up to DAY-1 is "operational" and will be re-analysed in the next month using final data inputs. Important to note is that differences introduced with every update is typically small. Data in current day are from "real-time" satellite model and will be updated when day finishes. Then, based on last satellite scenes we predict cloud motion in period in next 4-5 hours ("nowcasting"). The present moment and short period before is covered by "nowcasting" data as the last satellite scene is still in progress. This delay can take up to 30 minutes (depends on satellite scan frequency). After nowcasting period we use post-processed outputs from Numerical Weather Prediction models (NWP). Satellite based data is seamlessly integrated with NWP forecasting data within one response. In case of locations where real-time & nowcasting data is not available, NWP data is used for the whole current day. Also, not every location is supplied by ECMWF IFS data. In such case NOAA GFS data is used for all forecasted values. Meteorological data (TEMP, RH, WS, etc.) is comprised of NWP modeled data.
Spatial coverage of data available through API (valid for Oct 2016), click map to enlarge:
We regularly update light Light orange regions on the map with operational and historical dataare accessible via API and data is regularly updated. In the green polygons, real-time & nowcasting data is available. Main data parameters include GHI, DNI, DIF, GTI, PVOUT.
|satellite region||data availability since||historical data update||operational data update|
satellite scan frequency
in the beginning of every month,
whole previous month is re-calculated
|every day at 10:00 UTC (USA), 13:00 UTC (whole region)no||planned||30 minutes|
|MSG||2005-01-01||every day at 03:45 UTC||part of Europe, Kenya||15 minutes|
|MTSAT / HIMAWARI||2006-07-01||every day at 22:40 UTC||East China, Japan||30 min. (10 min. since Jan 2016 onward)|
Operational data daily update re-calculates two days: DAY-1 and DAY-2. Monthly update re-calculates the whole previous month as soon as completed. The purpose of those updates is described in this article. We gradually expands spatial coverage of satellite data accessible via API. To access operational and historical data in the gray areas on the map, please use Solargis climData online shop.