--- title: "Solar / Global Radiation Sensors & Monitoring | Aethair" description: "Solar (global) radiation is the total shortwave solar energy on a horizontal surface, in W/m². How pyranometers measure it and where to place them." url: https://aethair.io/parameters/solar_radiation/ --- Measurements · Radiation & Light # Solar / Global Radiation Also known as pyranometer, solar irradiance, global radiation Global (solar) radiation / irradiance. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure Solar / Global Radiation Monitoring](https://aethair.io/build/?params=solar_radiation) At a glance W/m² Radiation & Light 1 way to measure it - **Thiamis** 3 external instruments What it is ## What is solar radiation? Solar radiation, or global radiation, is the total shortwave energy arriving from the sun on a horizontal surface, measured in watts per square meter (W/m²). It is the sum of two parts: the **direct** beam coming straight from the sun's disc, and the **diffuse** radiation scattered across the whole sky by cloud, air, and aerosols. Reported as global horizontal irradiance, it rises and falls through the day with the sun's angle and is cut by cloud, haze, and shading. It covers the shortwave band (ultraviolet, visible, and near-infrared) that carries the sun's energy to the ground, and it is distinct from the narrower band of photosynthetically active radiation that plants use. Solar radiation is the primary energy input to the surface, driving temperature, evaporation, plant growth, and power generation alike, which makes it a cornerstone measurement in energy, agriculture, and meteorology. For solar-energy projects, irradiance is the fuel: it determines how much a photovoltaic array or thermal collector can produce, so measured radiation underpins yield prediction, performance monitoring, and the detection of soiling or faults. In agriculture it drives photosynthesis and, together with temperature and humidity, the evapotranspiration that governs crop water demand and irrigation scheduling. In meteorology and building science it feeds energy-balance and climate models and informs the design of shading, daylighting, and cooling loads. Across all of these, solar radiation is a supplied energy that everything else responds to, so measuring it accurately turns qualitative expectations about sun and cloud into quantitative inputs for design and control. How it is measured ## How Solar / Global Radiation Is Measured Global radiation is measured with a **pyranometer**, a sensor with a horizontal, upward-facing element under one or two glass domes that admit the full shortwave band while excluding longwave heat. Two technologies dominate: **thermopile** pyranometers, which sense the heat absorbed by a black surface and offer a flat spectral response classified under ISO 9060; and **silicon-photodiode** sensors, which are lower cost but respond over a narrower band. As a professional meteorological sensor rather than a built-in reading, a pyranometer is connected to a Thiamis gateway for continuous irradiance logging, and its glass dome must be kept clean and free of dew, frost, and dust to stay accurate. An instrument on Thiamis 3 A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account. ### Placing solar radiation sensors A pyranometer is mounted level, on an unshaded platform with a clear view of the whole sky dome and no obstructions (buildings, masts, trees) that would cast shadows or reflect extra radiation onto it during any part of the day or year. It should be sited away from light-colored walls and other reflective surfaces, kept accessible for cleaning, and leveled precisely, since even a small tilt biases the reading. For photovoltaic performance work the sensor is sometimes mounted in the plane of the array as well, to measure the irradiance the panels actually receive. ### Every device and option that measures Solar / Global Radiation 3 | Device / option | Type | Base platform | Measures | | - | - | - | - | | [Davis](https://aethair.io/sensors/davis-weather-stations/) · Davis Wizard III, Davis Wizard II, Davis Monitor… | Weather Stations | Thiamis | Solar / Global Radiation [Dew Point](https://aethair.io/parameters/dew_point/) [Heat Index](https://aethair.io/parameters/heat_index/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Leaf Temperature](https://aethair.io/parameters/leaf_temperature/) [Leaf Wetness](https://aethair.io/parameters/leaf_wetness/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) | | [Lufft](https://aethair.io/sensors/lufft-weather-stations/) · WS100, WS200, WS300… | Weather Stations | Thiamis | Solar / Global Radiation [Dew Point](https://aethair.io/parameters/dew_point/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) [Precipitation](https://aethair.io/parameters/precipitation/) [Barometric Pressure](https://aethair.io/parameters/pressure/) [Air Temperature](https://aethair.io/parameters/temperature/) | | [Gill Instruments](https://aethair.io/sensors/gill-instruments-weather-stations/) · MaxiMet-GMX100, MaxiMet-GMX200, MaxiMet-GMX240… | Weather Stations | Thiamis | Solar / Global Radiation [Dew Point](https://aethair.io/parameters/dew_point/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Barometric Pressure](https://aethair.io/parameters/pressure/) [Air Temperature](https://aethair.io/parameters/temperature/) [Wind Direction](https://aethair.io/parameters/wind_direction/) [Wind Speed](https://aethair.io/parameters/wind_speed/) | [Configure Solar / Global Radiation Monitoring](https://aethair.io/build/?params=solar_radiation) Where it is monitored ## Solutions That Monitor Solar / Global Radiation Each one links to the solution page showing what that industry measures it for. ### [Agriculture & Irrigation](https://aethair.io/solutions/agriculture/) Often added Soil moisture, microclimate, and frost warning ### [Heat Stress & Outdoor Work](https://aethair.io/solutions/heat-stress/) Often added WBGT for worksites, athletics, and events ### [Weather Stations & Meteorology](https://aethair.io/solutions/weather/) Often added Professional multi-parameter weather monitoring Related ## More in Radiation & Light [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [UV Index](https://aethair.io/parameters/uv/) [Radon](https://aethair.io/parameters/radon/) [Illuminance / Light](https://aethair.io/parameters/light/) Questions ## Solar / Global Radiation FAQ What is the difference between global, direct, and diffuse radiation? Global radiation is the total shortwave energy on a horizontal surface, made up of the direct beam from the sun's disc plus the diffuse radiation scattered by the sky. A standard pyranometer measures the global total; separating direct and diffuse needs additional instruments such as a shaded sensor or a tracker. How is solar radiation different from PAR? Solar radiation covers the whole shortwave band that carries the sun's energy, whereas photosynthetically active radiation (PAR) is only the visible portion that plants use for photosynthesis. They are measured with different sensors and reported in different units, so one cannot simply be converted into the other without assumptions. Why must the sensor be level and unshaded? Because a pyranometer measures energy on a horizontal plane, any tilt biases the reading, and any shadow or nearby reflective surface adds or removes radiation that is not representative of the sky. Precise levelling, a clear sky view, and a clean dome are what keep the measurement accurate. How do I monitor solar radiation? Pair a Thiamis gateway with a pyranometer, mounted level and unshaded and kept clean, for continuous irradiance logging. Use the configurator to combine solar radiation with temperature, humidity, wind, and other weather and agricultural parameters so that irradiance can be interpreted alongside the conditions it drives.