The AIRS Relative Humidity (500 hPa, Day) layer indicates the percent relative humidity at varying pressure levels measured in hectopascals (hPa). The vertical profile information produced by the AIRS instrument augments radiosonde data. Most radiosonde launch stations are situated on land, and the AIRS instrument improves this information as it can provide data for locations all over the globe such as large swaths of the ocean that do not have any regular measurements taken. The Relative Humidity layer is available at 500hPa, 700hPa, 850hPa. 500hPa is approximately 5.5 km or 18,000 feet, 700hPa is approximately 3 km or 10,000 feet and 850hPa is approximately 1.5 km or 5,000 feet. This information helps improve world weather observing and in improving the skill in making mid and long range weather forecast.

The Atmospheric Infrared Sounder (AIRS) is an instrument on board the Aqua satellite. The AIRS Relative Humidity science parameter is a parameter of the AIRS Level 2 Near Real Time standard retrieval product using AIRS (AIRS2RET_NRT). The imagery resolution is 2 km and sensor resolution is 45 km. The temporal resolution is daily.

References: GES DISC - AIRS2RET_NRT: AIRS/Aqua L2 Near Real Time (NRT) Standard Physical Retrieval (AIRS-only) V006; GES DISC - Near Real-Time Data; NOAA National Weather Service - Radiosonde Observations; AIRS - The AIRS instrument suite physical retrievals