AVHRR2

The Advanced Very High Resolution Radiometer 2 (AVHRR2) is a multispectral scanning radiometer designed to measure the Earth's surface and atmosphere in five spectral channels. Developed by the National Oceanic and Atmospheric Administration (NOAA), it is part of the series of AVHRR instruments launched aboard polar-orbiting satellites, including the NOAA-9, NOAA-11, NOAA-14, and NOAA-16 satellites. The AVHRR2 was introduced to improve upon its predecessor, the AVHRR1, by enhancing spatial and spectral resolution while maintaining compatibility with existing data processing systems.

AVHRR2 operates in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum. Its five spectral bands include:

- Channel 1 (0.58–0.68 µm) for visible light imaging,

- Channel 2 (0.725–1.1 µm) for vegetation and cloud detection,

- Channel 3 (3.55–3.93 µm) for thermal infrared measurements,

- Channel 3A (1.58–1.64 µm) for atmospheric water vapor detection,

- Channel 4 (10.3–11.3 µm) and Channel 5 (11.5–12.5 µm) for surface and cloud temperature measurements.

The instrument provides global coverage with a swath width of approximately 2,900 kilometers, capturing data at a spatial resolution of 1.1 kilometers at nadir. AVHRR2 data is widely used in various applications, including weather forecasting, climate monitoring, oceanography, and environmental studies. Its long-term data record, spanning decades, makes it valuable for analyzing trends such as sea surface temperature variations, vegetation indices, and cloud cover changes.

The AVHRR2’s legacy continues through its successor, the AVHRR3, which further refined the instrument’s capabilities while retaining backward compatibility. Despite being retired from active service, AVHRR2 data remains a critical resource for historical and ongoing research.