Other Names
Aerosol Absorbing Index, Aerosol Absorbing Indicator, AI, AAI
Definition
It is an index that detects the presence of uv-absorbing aerosols such as dust and soot.
TOMS Aerosol index (AI) is based on a spectral contrast method in a UV region where the ozone absorption is very small. It is the difference between the observations and model calculations of absorbing and non absorbing spectral radiance ratios. For TOMS, AI is defined as
AI = 100 [ log10 (I360/I331)measured - log10 (I360/I331)calculated]
Positive values of Aerosol Index generally represent absorbing aerosols (dust and smoke) while small or negative values represent nonabsorbing aerosols and clouds. The Index can be interpreted in terms of optical depth if the index of refraction, particle size distribution, and the height of the aerosol layer are known from other measurements.
GOME (ERS-2) defines similar index called Absorbing Aerosols Indicator (AAI). Following TOMS AI definition GOME AAI also uses two wavelength intervals around 340 nm and 380 nm.
However, POLDER on ADEOS-1 & 2 define Aerosol Index (for small size particles) as the product of the retrieved aerosol optical thickness and Angstrom exponent.
Applications
| (1) Atmospheric correction of remotely sensed surface features | (5) Air Quality |
| (2) Monitoring of sources and sinks of aerosols | (6) Health and Environment |
| (3) Monitoring of volcanic eruptions and forest fire | (7) Earth Radiation Budget |
| (4) Radiative Transfer Model | (8) Climate Change |
GES DISC Datasets
Other sources for data
Atmos Composition
