Vaisala Energy Support
What is Global Horizontal Irradiance?
The radiation reaching the earth's surface can be represented in a number of different ways. Global Horizontal Irradiance (GHI) is the total amount of shortwave radiation received from above by a surface horizontal to the ground. This value is of particular interest to photovoltaic installations and includes both Direct Normal Irradiance (DNI) and Diffuse Horizontal Irradiance (DIF).
DNI is solar radiation that comes in a straight line from the direction of the sun at its current position in the sky. DIF is solar radiation that does not arrive on a direct path from the sun, but has been scattered by molecules and particles in the atmosphere and comes equally from all directions.
More Solar Online Tools Questions
- Which weather data source should I pick?
- What's the latest month available in the solar time series tool?
- What updates were applied to the datasets in November 2019?
- What solar values are shown on the map?
- How do I enter a location?
- Why does the map disappear?
- How do I interpret the graphs provided by the Monthly Mean Irradiance Tools in the Prospecting Tools?
- What do the Annual Mean Irradiance Tools in the Prospecting Tools provide?
- How can I compare sites side-by-side in the Prospecting Tools?
- How much area is covered by the Solar Prospecting Tools?
- How accurate are the Solar Prospecting Tools?
- What data is shown in the Solar Time Series Viewer?
- What data can I get from the Solar Time Series Download tool?
- What is the Vaisala 1.0 dataset?
- What is the Vaisala 1.1 dataset?
- What is the Vaisala 1.2 dataset?
- What is the Vaisala 2.0 dataset?
- What is the Vaisala 2.1 dataset?
- The datasets give different answers. Which one is right?
- How accurate is the data in the Solar Time Series Tools?
- What are the units of irradiance?
- What is the “TMY” Data Type in the Solar Time Series Download tool?
- What is the “Long-Term” Data Type in the Solar Time Series Download tool?
- Why does the data not match my observations?
- How do I input CSV files into PVSyst?
- How can I input time series data into PVSyst?
- What is Direct Normal Irradiance?
- What is Diffuse Horizontal Irradiance?
- What affects solar radiation at a given site?
If you didn't find what you were looking for, please contact 3TIER Support for additional assistance.