Terra MODIS Fluorescence Line Height (FLH): Global Near Real-time Ocean Data

The Ocean Biology DAAC produces near real-time (NRT) Fluorescence Line Height (FLH) data using satellite measurements from the Terra MODIS instrument. This data suite quantifies red chlorophyll-a fluorescence emitted by phytoplankton, measured in units of W m⁻² µm⁻¹ sr⁻¹. It is designed for rapid monitoring, though inputs and calibration are noted as less than optimal.

Use Cases

• Detecting and tracking harmful algal blooms (HABs) based on elevated fluorescence line height values.
• Identifying productive ocean waters based on phytoplankton fluorescence signals.
• Assessing phytoplankton physiology and stress based on variations in fluorescence measurements.

Strengths

• Provides near real-time (NRT) data for rapid environmental monitoring.
• Includes the geophysical variable 'nflh' (Normalized Fluorescence Line Height) and 'ipar' (Instantaneous Photosynthetically Available Radiation).
• Data is produced by the NASA Ocean Biology DAAC, indicating an authoritative source for satellite ocean color products.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Uncertainties increase in optically complex coastal and inland waters, as noted in the algorithm documentation.
• Row count is unknown, which may limit suitability assessment for large-scale modeling.

Provenance

Source

NASA Ocean Biology DAAC (OB_CLOUD) via the nasa_earthdata platform.

Collection Method

Satellite remote sensing from the Terra MODIS instrument, with data processed using the best-available ancillary meteorological and ozone data.

Freshness

Near real-time (NRT), providing a snapshot from a short time period within a single orbit.

Geography

Global