Apparent Visible Wavelength (AVW) quantifies the spectral center of water-leaving reflectance across the visible range, reported in nanometers. This Level-4 mapped product from NASA's Aqua MODIS satellite is used for water-type classification and algorithm selection. The data is produced by OB_CLOUD.
Use Cases
- Classify water types (e.g., oligotrophic vs. productive) based on the `avw` value.
- Guide chlorophyll-a (`chlor_a`) retrieval algorithm selection by using `avw` as a blending parameter.
- Detect regional changes in water optical properties by analyzing time-series of the `avw` variable.
- Provide context for other ocean color products like `Kd_490` (diffuse attenuation) and `PAR` (photosynthetically available radiation).
Strengths
- Provides a single, globally mapped geophysical variable (`avw`) for ocean color analysis.
- Derived from NASA's Aqua MODIS satellite, a long-standing source of oceanographic remote sensing data.
Limitations
- Interpretations of the `avw` variable can be ambiguous in optically complex coastal and inland waters.
- Data quality is contingent on flags for clouds, glint, and aerosols, which must be reviewed by the user.
Provenance
- Source
- NASA Earthdata (OB_CLOUD)
- Collection Method
- Derived from water-leaving reflectance spectra (Rrs) measured by the MODIS instrument on the Aqua satellite.
- Time Range
- null
- Freshness
- null
- Geography
- Global ocean coverage.