Classification of solar radiation sensors: a) Solar radiation intensity meter: Also known as total solar radiation (direct radiation + diffuse radiation). They are widely used in meteorological stations, solar energy systems and agricultural research. b) Direct radiometer: Measures direct solar radiation, also known as direct normal irradiance (DNI). They are used in the assessment of solar energy resources, the design of solar energy systems and atmospheric research. c) Ground radiation intensity meter: Measures long-wave infrared radiation emitted from the Earth's surface and atmosphere. They are crucial for studying the Earth's energy budget, climate research and weather forecasting. d) Light and effective Sensor (PAR Meter) : Photosynthetically active radiation data is of great significance for the research of plant growth, plant photosynthesis, and vegetation index. e) Ultraviolet sensor (UV sensor) : Ultraviolet sensors are specifically designed to measure the level of ultraviolet radiation from the sun. They are applied in ultraviolet irradiation for monitoring human health purposes, environmental monitoring and ultraviolet sterilization processes. f) Spectral radiometer: A spectral radiometer measures the entire electromagnetic spectrum of solar radiation and provides detailed spectral information. They are used in solar energy research, atmospheric research and material characterization.