Time Series of Bio-Optical Properties in a Subtropical Gyre: Implications for the Evaluation of Interannual Trends of Biogeochemical Properties

Abstract

With a validated Quasi-Analytical Algorithm, an 11 year (1998-2008) monthly time series of the primary optical properties of waters in the center of the South Pacific gyre was developed from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS). Also derived are chlorophyll a (Chi a) concentrations with the operational empirical algorithms for SeaWiFS and MODIS. The optical properties include the absorption coefficient (at 443 nm) of phytoplankton (aph) and that of the combination of detritus and gelbstoff (adg). From these time series, we further derived their annual background (summer low) and seasonal intensity (the difference between winter high and summer low). These time series show that (1) the optical properties have different seasonal and interannual variations, indicating different dynamics of these properties in the subtropical gyre; (2) there is a decreasing trend (r-squared = 0.24) of the background apn in the 1998-2008 period and an increasing trend of the aph seasonal intensity (r-squared = 0.11) for this period, and both trends are not statistically significant; (3) the aph time series agrees with the Chi a time series at the seasonal scale, but differs with respect to interannual variations; and (4) different interannual trends could be inferred with different time frames. These results emphasize that it is difficult to draw unequivocal conclusions about long-term trends of biogeochemical properties in the oceans with the current relatively short bio-optical records. To clarify and predict such trends, it is critical to get a full account of the forces that are responsible for the seasonal and interannual variations of these properties.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2010
Accession Number
ADA537102

Entities

People

  • Bertrand Lubac
  • Chuanmin Hu
  • Marlon Lewis
  • Robert Armone
  • Shaoling Shang
  • Yonghong Li
  • Zhongping Lee

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Absorption
  • Absorption Coefficients
  • Algorithms
  • Climate Change
  • Coefficients
  • Dynamics
  • Intensity
  • Jet Propulsion
  • Measurement
  • Oceanography
  • Oceans
  • Optical Properties
  • Raman Scattering
  • Remote Sensing
  • Scattering
  • Statistical Analysis
  • Test And Evaluation

Readers

  • Atmospheric Remote Sensing.
  • Atmospheric Science/Meteorology
  • Regression Analysis.

Technology Areas

  • AI & ML
  • AI & ML - Bayesian Inference