Infrared Thermometer: Sky brightness temperature - irt

The infrared thermometer (IRT) is a ground-based radiation pyrometer that measures the equivalent blackbody brightness temperature of the scene in its field of view. The downwelling version has a narrow field of view for measuring sky temperature and detecting clouds. The upwelling version has a wide field of view for measuring the narrowband radiating temperature of the ground surface.

红外温度计（infrared thermometer, IRT）是一种地面辐射高温计，可测量其视场内场景的等效黑体亮度温度。其中下行式型号采用窄视场设计，用于测量天空温度并探测云层；上行式型号则配备宽视场，能够测量地表的窄带辐射温度。