Report: TR 2013/51
Author: M Pinkerton, S Wood, J Zeldis, M Gall (National Institute of Water & Atmospheric Research Ltd)
Waikato Regional Council seeks to use satellite remote sensing methods to provide spatial data on ocean colour, to help management of the Hauraki Gulf region.
Coastal waters exhibit high natural variability in their characteristic properties, both spatially and seasonally. Observations of the ocean from optical sensors on satellites can complement measurements of water properties from boats and moorings, and provide synoptic distributions of these properties over large areas, at daily and longer timescales.
Local (regional) validation and tuning of processing methods is required to use satellite observations. In-water measurements of total suspended matter (TSM) and chlorophyll-a (chl-a) concentration (a proxy for phytoplankton biomass) in the Hauraki Gulf region were assembled to assess and develop “locally-tuned” satellite processing methods.
These locally-tuned algorithms were applied to more than a decade of satellite observations from the NASA MODIS-Aqua sensor, in order to assess typical conditions and characterise variability of water constituents.
|1.2||Coloured water constituents||7|
|1.3||Remote sensing of ocean colour||8|
|1.5||Structure of report||10|
|2||Objective 1: Evaluation of satellite products||10|
|2.1||Source of satellite data||10|
|2.3||Satellite data grid||10|
|2.4||Testing and tuning satellite in-water algorithms||11|
|2.5||Long-term median, high and low satellite data values||11|
|2.6||In situ data available||12|
|2.7||Satellite algorithms for total suspended matter (TSM)||12|
|2.8||Satellite algorithms for chlorophyll-a concentration (chl-a)||14|
|2.8.1||Band-ratio chl-a algorithm (CHL)||16|
|2.8.2||Fluorescence line height (FLH)||16|
|2.8.3||QAA phytoplankton absorption product (APH-QAA)||16|
|2.8.4||GSM phytoplankton absorption production (APH-GSM)||17|
|3||Objective 2: Satellite total suspended matter||18|
|4||Objective 3: Satellite chlorophyll-a concentration||21|
|Appendix A: Number of pixels used in data compilations||30|