About the Products
CLIMCAPS-Aqua Level 2 & 3 Products
CLIMCAPS retrieves multiple Earth surface, cloud and atmospheric state variables from AIRS radiances. These are available as Level 2 products, organized according to measurement swaths and geolocated. Level 3 products on a 1 x 1 degree grid are also provided. Because AIRS measures the globe twice daily, two sets of retrieval data (referred to as ascending and descending) are available each day with global coverage.
There are two processing streams of each Level 2 and Level 3 data type. They differ in the combination of instrument radiances used in the retrieval process.
AIRS-only: This record is only based on observations from the AIRS instrument and covers the entire duration of the mission.
AIRS+AMSU: This record is based on combined AIRS and AMSU observations and covers the period 30 August 2002 to 24 September 2016 (about 14 years), when AMSU-A2 failed.
Level 2 Data Products Overview
The Level 2 data product includes geophysical retrievals, e.g., of temperature, water vapor, clouds, and trace gases. Data files contain six-minute granules, generally 240 per day, of data. Cloud cleared radiances are provided in separate product files. Both types of files are available with data from either AIRS-only or AIRS+AMSU instruments.
Level 3 Data Products Overview
The CLIMCAPS Level 3 products contain gridded statistical summaries of the geophysical variables. The Level 3 products are averaged over daily and monthly time spans for both AIRS-only and AIRS+AMSU Level 2 products. Each of the resulting product types is available with either specific or comprehensive quality control (see NASA CLIMCAPS L3 Format Definition V2).
Geophysical Product Summaries
A list of the atmospheric variables CLIMCAPS retrieves is provided in the CLIMCAPS Science Application Guide with associated information and detailed guides and descriptions for some of the main variables. These main variables are temparature, water vapor, ozone, carbon dioxide, carbon monoxide, methane, cloud fraction and cloud top pressure. Other primary variables are cloud liquid water, nitric acid, nitrous oxide and sulphur dioxide, as well as surface temperature, emissivity and reflectivity. Derived variables calculated from the retrieved variables are also listed in the CLIMCAPS Science Application Guide and inlude cloud top temperature, relative and specific humidity, geopotential height, total precipitable water, and total column cloud liquid water.