TOVS

TOVS stands for the TIROS Operational Vertical Sounder. It was a series of instruments designed to measure temperature and humidity profiles in the Earth's atmosphere from space. The first TOVS instrument was launched aboard the TIROS-N satellite in 1978, and subsequent instruments were flown on NOAA satellites for several decades. The primary goal of TOVS was to provide data for operational weather forecasting by retrieving vertical atmospheric profiles of temperature and moisture. These profiles are crucial for understanding atmospheric stability, cloud formation, and the movement of weather systems.

The TOVS instrument package typically consisted of three main components: the Advanced Very High Resolution Radiometer (AVHRR), the Stratospheric Sounding Unit (SSU), and the Microwave Sounding Unit (MSU). The AVHRR provided high-resolution imagery in visible and infrared channels, used for cloud detection and surface temperature measurements. The SSU measured temperature profiles in the stratosphere, and the MSU measured temperature profiles in the troposphere and lower stratosphere using microwave frequencies, which are less affected by clouds. The data collected by TOVS instruments were processed into atmospheric soundings, which were then assimilated into numerical weather prediction models. This continuous stream of data from TOVS significantly improved the accuracy and timeliness of weather forecasts. Later versions of TOVS were superseded by the Advanced TOVS (ATOVS) and later instruments like the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS).