Horizontal Irradiance (GHI – Mean Irradiance)

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Map Information

Total incoming solar radiation on a horizontal surface, including both direct and diffuse components.

Data Source:
Environmental Data
Units:
W/m²
Coverage:
GLOBAL
Citation:
Mazzella, J. (2026). Global Horizontal Irradiance (GHI) Raster, 2020–2024. AtmosphericIQ LLC / Engineering Director, Inc. Derived from the Copernicus Climate Change Service (C3S) ERA5 reanalysis dataset. Hersbach, H., et al. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. ECMWF Copernicus Climate Data Store (CDS). https://cds.climate.copernicus.eu
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Technical Specifications

Horizontal Irradiance (GHI) – Mean Surface Solar Radiation Downwards

Global | ~1 km Resolution | 2020–2024


Short Description

This dataset represents the spatial distribution of global horizontal irradiance (GHI), defined as the total incoming shortwave solar radiation received at the Earth's surface. GHI includes both direct beam and diffuse radiation components under all-sky conditions.


Technical Specification

The dataset is derived from ERA5 Surface Solar Radiation Downwards (SSRD) fields and represents mean global horizontal irradiance for the period 2020–2024.

ERA5 hourly radiation data were aggregated across the 2020–2024 period to produce a multi-year climatological mean expressed as radiative flux.

This dataset is developed by AtmosphericIQ LLC and processed for distribution and deployment by Engineering Director, Inc.


Key Characteristics

  • Units: watts per square meter (W/m²)
  • Represents total incoming solar radiation at the surface (direct + diffuse)
  • Derived from ERA5 SSRD fields
  • Represents climatological mean conditions for 2020–2024

Spatial Characteristics

  • Coordinate System: GCS_WGS_1984
  • Native Resolution: ~0.25°
  • Resampled Resolution: ~1 km (30 arc-second)
  • Coverage: Global (±85.0511° for web compatibility)

Role in SSI™ Model

Global Horizontal Irradiance (GHI) is a primary radiative variable incorporated into the Solar Suitability Index (SSI™) model developed by AtmosphericIQ LLC.

As a measure of total solar energy available at the surface, GHI represents a fundamental driver of solar resource potential and contributes significantly to the SSI™ suitability scoring framework.

This dataset is provided as a supporting climatic input layer and does not independently represent solar suitability.


Applications

  • Solar resource assessment
  • Photovoltaic and solar thermal analysis
  • Climatological and environmental modeling
  • Geospatial screening workflows

Data Source

Derived from Copernicus Climate Change Service (C3S) ERA5 reanalysis data, with processing including temporal aggregation (2020–2024), spatial resampling to ~1 km resolution, and web-compatible clipping.


Related SSI™ Dataset

This dataset is a supporting climatic input to the Solar Suitability Index (SSI™), a global multi-parameter model developed by AtmosphericIQ LLC.

For the full solar suitability model and derived classification datasets, see:
Global Solar Suitability Index (SSI™) – Continuous Score (1–100)


Data Access & API Services

This dataset is available through Engineering Director, Inc. platforms:
www.engineeringdirector.com

Use beyond visualization, including API access, automated queries, or integration, is subject to the Engineering Director API Terms of Service.


Legal & Licensing

© 2026 AtmosphericIQ LLC and Engineering Director, Inc. All rights reserved.

This dataset is provided for informational and analytical use only and is supplied "as is" without warranty of any kind. Users assume all risk associated with its use.

Data Distribution Analysis

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Linear Scale Distribution
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Logarithmic Scale Distribution
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