Accession Number:

ADA585237

Title:

Impact of Bio-optical Data Assimilation on Short-term Coupled Physical, Bio-optical Model Predictions

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV

Report Date:

2013-04-30

Pagination or Media Count:

17.0

Abstract:

Data assimilation experiments with the coupled physical, bio-optical model of Monterey Bay are presented. The objective of this study is to investigate whether the assimilation of satellite-derived bio-optical properties can improve the model predictions phytoplankton population, chlorophyll in a coastal ocean on time scales of 1-5 days. The Monterey Bay model consists of a physical model based on the Navy Coastal Ocean Model and a biochemical model which includes three nutrients, two phytoplankton groups diatoms and small phytoplankton, two groups of Zooplankton grazers, and two detrital pools. The Navy Coupled Ocean Data Assimilation system is used for the assimilation of physical observations. For the assimilation of bio-optical observations, we used reduced-order Kaiman filter with a stationary forecast error covariance. The forecast error covariance is specified in the subspace of the multivariate bio-optical, physical empirical orthogonal functions estimated from a monthlong model run. With the assimilation of satellite-derived bio-optical properties chlorophyll a or absorption due to phytoplankton, the model was able to reproduce intensity and tendencies in subsurface chlorophyll distributions observed at water sample locations in the Monterey Bay, CA. Data assimilation also improved agreement between the observed and model-predicted ratios between diatoms and small phytoplankton populations. Model runs with or without assimilation of satellite-derived bio-optical observations show underestimated values of nitrate as compared to the water sample observations. We found that an instantaneous update of nitrate based on statistical relations between temperature and nitrate corrected the model underestimation of the nitrate fields during the multivariate update.

Subject Categories:

  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE