|
|
|
|
| NIRE Annual Report |
| 1998 |
Estimation of Primary Production by
Marine Environment Division |
|---|
Objectives
Primary Production is one of the most important processes for ecosystem dynamics and material cycling. Recent development of remote sensing technology allows to detect spatial distribution of chlorophyll a and temperature at the sea surface from space. With the chlorophyll a and temperature information, primary production in the ocean should be able to estimate. Spatial distribution of primary production off Sanriku on April 26, 1997, was estimated with the data of Ocean Color and Temperature Sensor (OCTS) on board of Advanced Earth Observation Satellite (ADEOS).
Results
Primary production per chlorophyll a was assumed to be controlled by number of photon absorbed by phytoplankton and ambient temperature. Vertical distribution of photosynthetically active radiation was calculated from the diffuse attenuation coefficients of seawater and chlorophyll a. Using the ship-observed insolation, chlorophyll a and temperature, vertical distribution of primary production was estimated and compared with ship-observed primary production data. Primary production was reasonably estimated from surface chlorophyll a concentration and temperature assuming vertically constant.
With surface chlorophyll a concentration and temperature estimated by OCTS, spatial distribution of integrated primary production through water column was estimated off Sanriku where a warm core ring was placed. The chlorophyll a concentration was high around the warm core ring and lower in the warm core ring and surrounding waters. Spatial distribution of integrated primary production was basically similar to the spatial distribution of chlorophyll a.