The application of satellite imagery to a predictive model of cetacean density

Tom Norris1 Christine Loftus1 Jay Barlow2 Ed Armstrong3

1 Science Applications International Corporation2 NOAA-Southwest Fisheries Science Center3 Jet propulsion Laboratory, Caltech

Objectives

• To compare the results of a predictive model of marine mammal distribution and abundance that uses in-situ (i.e. ship aquired) oceanographic data versus satellite aquired oceanographic data.

• To examine the effects of temporal averaging of satellite data on model results.

Methods: data collection• Marine mammal surveys were conducted by

NOAA-SWFSC in the temperate eastern North Pacific in ’91, ’93, ’96 & 2001.

Cetacean survey data:line-transect methods used.

Chl-a and SST data: standard techniques used.

ORCAWALE 2001

• A generalized additive model will be developed by SWFSC (after Forney, 2000) based on archival (e.g. bathymetry) and ship-acquired (in-situ) environmental data for years: 1991, 1993, and 1996.

• Model will be evaluated for inter-annual predictive power using data from the 2001 fall marine mammal survey (ORCAWALE cruise).

Methods: model development

Methods: satellite data• Model applied and tested using satellite derived

environmental data - specifically SST and chl-a.

AVHRR - SST SeaWIFS - chl-a

Methods: satellite data sets

8-day

monthly

seasonal

best pixel

SeaWiFS AVHRR

Matchup processing(SAIC)

annual

Matchup processing(SAIC)

Methods: best pixel matchup database

Best pixel

Daily 8-day monthly seasonal annual

daily match?

yes

no

8-day match?

yes

no

monthly match?

yesseasonal match?

yesannual match

no

no

Methods: comparison of model results

• Compare model results from satellite vs. ship acquired data inputs.

• Examine effects of temporal averaging of satellite data on model results.

• Quantify differences with statistical tests.• Qualitatively assess differences with maps.

• Satellite data are synoptic and therefore may be a better indicator of overal environmental conditions related to habitat of marine mammals.

• pixel dimension = 9 km2.• covearage is widespread (with some exceptions).• archival satellite data is readily available (for

running models).

• in-situ data are collected continuously but are avaeraged and characterized as point

measurements.

In-situ vs. satellite data

Timeline

• August 2003 - Begin effort.

• January 2003 - Complete match-up database.

• March 2003 - Complete model execution for all data.

• May 2003 - Complete model validation and testing.

• July 2003 - Analysis, summary, and final report.

Future efforts

Model development: • Develop a model using satellite data for 2001survey

(NOTE: chl-a / SeaWiFS data do not exist for ‘91- ‘96).

• Validate satellite data model for other years (once additional marine mammal survey data are available).

• Include SST and chl-a and bathymetry gradients as and hydrographic modeled data (e.g. vertical temp. structure) in model development

Other:• Test for auto-correlations between SST gradients, chl- a gradients, and bathymetry gradients.