In this document
You will learn what services, data types, and features are included in every Solargis Forecast subscription tier.
Forecast data parameter specifications
The following table details all parameters available in Solargis Forecast services. It specifies the units and source of each parameter.
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Parameter | API parameter | Unit | Type | Source | Forecast Basic | Forecast Professional/ Enterprise | Forecast: Historical Period | Forecast: Portfolio Aggregation |
Global Horizontal Irradiation | GHI | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Direct Normal Irradiation | DNI | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Diffuse Horizontal Irradiation | DIF | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Global Tilted Irradiation for fixed-tilt PV modules * | GTI | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Global Tilted Irradiation for PV modules on trackers * | GTI | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Clear-sky Global Horizontal Irradiation | GHI_C | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Clear-sky Direct Normal Irradiation | DNI_C | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Global tilted clear-sky irradiance * | GTI_C | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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GHI high estimate (10 % probability of exceedance) | GHI_UNC_HIGH | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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GHI low estimate (90 % probability of exceedance) | GHI_UNC_LOW | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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GTI high estimate (10 % probability of exceedance) | GTI_UNC_HIGH | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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GTI low estimate (90 % probability of exceedance) | GTI_UNC_LOW | kWh/m2, Wh/m2, W/m2 | Solar | Solargis CMV, NWP |
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Cloud identification quality flag | CI_FLAG | - | Solar | Solargis |
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Alias for CI_FLAG | FLAG_R | - | Solar | Solargis |
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Sun Altitude (Elevation) Angle | SE | ° | Solar | Solargis |
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Sun Azimuth Angle | SA | ° | Solar | Solargis |
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Clear-sky index | KC | - | Solar | Solargis CMV |
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Clearness index | KT | - | Solar | Solargis CMV |
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Incidence angle of direct irradiance * | INC | ° | PV | Solargis |
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Photovoltaic Output for fixed-tilt PV modules * | PVOUT | kW, kWh | PV | Solargis CMV, NWP |
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Photovoltaic Output for PV modules on trackers * | PVOUT | kW, kWh | PV | Solargis CMV, NWP |
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PVOUT high estimate (10 % probability of exceedance) * | PVOUT_UNC_HIGH | kW, kWh | PV | Solargis CMV, NWP |
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PVOUT low estimate (90 % probability of exceedance) * | PVOUT_UNC_LOW | kW, kWh | PV | Solargis CMV, NWP |
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PV module temperature * | TMOD | °C | PV | Solargis |
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Tilt of inclined surface * | TILT | ° | PV | Solargis |
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Aspect of inclined surface * | ASPECT | ° | PV | Solargis |
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Air Temperature at 2 meters | TEMP | °C | Climate | NWP |
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Wet Bulb Temperature | WBT | °C | Climate | NWP |
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Dew Point Temperature | TD | °C | Climate | NWP |
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Wind Speed | WS | m/s | Climate | NWP |
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Wind Direction | WD | ° | Climate | NWP |
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Wind Gust | WG | m/s | Climate | NWP |
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Wind speed at 100 meters | WS100 | m/s | Climate | NWP |
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Wind direction at 100 meters | WD100 | ° | Climate | NWP |
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Atmospheric Pressure | AP | hPa | Climate | NWP |
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Relative Humidity | RH | % | Climate | NWP |
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Precipitable Water | PWAT | kg/m2 | Climate | NWP |
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Precipitation Rate | PREC | mm/h | Climate | NWP |
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Water equivalent of accumulated snow depth | SDWE | kg/m2 | Climate | NWP |
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Water equivalent of fresh snowfall rate | SFWE | kg/m2/hour | Climate | NWP |
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* This parameter needs a PV system defined in the request, at least in a minimal setup as follows:
<pv:system installedPower="1">
<pv:module type="CSI"/>
<pv:inverter/>
<pv:losses/>
</pv:system>Forecast model details
The spatial resolution and update rate of Solargis Forecast for a particular location and time horizon depends on the forecast model used. Solargis Forecast uses several forecasting models – our proprietary Cloud Motion Vector (CMV) model, and four different Numerical Weather Prediction (NWP) models. These models are summarized in the table below.
As a general statement, nowcasts and short-term forecasts for solar and PV parameters are derived from the Solargis CMV model, with sub-hourly update rates, and ~4 km spatial resolution. Forecasts for meteorological parameters for any time horizon, solar and PV parameters beyond approximately the next 3 hours are derived from a blend of NWP models, with an update rate of 6 hours, and at least ~13 km spatial resolution. In the continental USA, the forecast for the next 2 days is available with an hourly update rate and approximately 3 km spatial resolution.
Model | Coverage | Temporal coverage up to | Spatial resolution | Update rate |
CMV model by Solargis | Global | Next approx. 3 hours | 0.033° (~4 km) | 5 minutes in the contiguous USA 10 minutes in the Americas and East Asia/Pacific 15 minutes in Europe, Africa, and Asia |
Continental USA (CONUS) | D+2 | ~3 km | Hourly | |
Global | D+7 | ~13 km | 6 hours globally | |
Global | D+10 | ~8 km | 6 hours globally | |
Global | D+14 | ~13 km | 6 hours globally |
Forecast subscriptions - technical details
| Forecast Basic | Forecast Professional | Forecast Enterprise | Forecast: Historical Period | Forecast: Portfolio Aggregation |
Geographical coverage | Land surface and coastal seas between latitudes 60°N to 56°S and between 60°N and 65°N in Scandinavia and America (Figure 1) | ||||
Temporal resolution (time step) | Hourly | Up to 5 minutes | Up to 5 minutes | Up to 5 minutes | Up to 5 minutes |
Temporal coverage for Forecast data | Today to D+7 | Today to D+14 | Today to D+14 | Past two complete calendar years for horizons H0, H1, H2, H3 D+0 D+1, D+2, D+3 | Today to D+14 |
Data update rate for up to approx. 3 hours ahead | Six hours | Up to 5 minutes for PVOUT, GHI, DNI, DIF, GTI (including clear sky and uncertainty variants - Figure 1) Six hours for all other parameters One hour for all other parameters in CONUS | Up to 5 minutes for PVOUT, GHI, DNI, DIF, GTI (including clear sky and uncertainty variants - Figure 1) Six hours for all other parameters One hour for all other parameters in CONUS | n/a | Up to 5 minutes (Figure 1)
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Data update rate for data beyond approx. 3 hours ahead | Six hours | Six hours One hour in CONUS up to D+2 | Six hours One hour in CONUS up to D+2 | n/a | Six hours |
Figure 1: Geographical coverage of Solargis Forecast data