Incorporating Sea-surface Temperature to the light-based geolocation model, TrackIt

60th Annual International Tuna Conference

Chi Lam (Tim), Anders Nielsen and John Sibert

http://www.soest.hawaii.edu/PFRP/Kiefer Lab

http://netviewer.usc.edu/

Objectives of the talk

1. Highlight the features of various “kf” Kalman filter geolocation models

2. Show how TrackIt works with sea-surface temperature matching

3. Help appreciate the details and practical usage of the “kf” models

the wine tasting experience to geolocation

A common 2-step approach in geolocation

• Get raw daily positions from tag manufacturer processing

• Reconstruct most probable positions from the raw estimates

• A disconnected one-way process – no feedback and limited use of the original time series

• Extreme outliers are still problematic

Manufacturer Software

kftrack

kfsst

ukfsst

Others

e.g. tidal methods, Easy-Fish Tracker

Goals of the “kf” models

To give us• a track of geographic positions • some ideas about the uncertainities• some quantitative movement parameters

The “kf” familySimilarities

• Underlying movement model– random walk with drift and diffusion

• Observation model– predicts and describes observation error at any given position

• Kalman filter (extended (EKF) or unscented (UKF) )

• Maximum likelihood estimated model parameters

• Most probable track– Weighted average of what is learned from the current position’s data

and the entire track

Differences

Quick recap of the TrackIt model

u, v – velocity in North-South, East-West direction

D – diffusion

Nielsen & Sibert 2007. Can J Fish Aquat Sci 64

Model 2/3

Model 3/3

Raw geolocations vs. TrackIt

Differentscale

Adding sea-surface temperature

Data scenarios

Sea-surface temperature (SST) imagery

1. Reynolds (NOAA old OI set) 1 deg, Weekly

2. NOAA OIsst version 1 (AVHRR only) 0.25 deg, Daily

3. Blended (D. Foley, Coastwatch) 0.1 deg, 5-day

4. MODIS Aqua (NASA GSFC) 0.05 deg, 8-day

3 Mako sharks (SPOT+PAT)From S. Kohin and D. Holts

(SWFSC)

Drifter (with PAT attached)From M. Musyl

(U Hawaii/ NOAA)

Light only vs.

HighRes

Low

Usage tips

1. Always look at the confidence interval (ci)

2. SST may help, but not all the time3. SST works best when there is a sharp gradient4. Imagery resolution doesn’t matter too much5. Pay attention to the smoothing radius (r)6. Overall, SST reduces the width of the confidence region

7. Convergence for a fit is needed!

Reduce the• No. of parameters estimated

(e.g. bsst.ph = -1)• Resolution of SST imagery

(e.g. Reynolds, fixed radius)

Use• Better initial values

(e.g. D.init = 300)

… a balancing act

Just give me the conclusions…

Wine tasting guide to TrackIt

What you will see A. Light only

240 242 244 246 248

24

26

28

30

32

34

B. Reynolds SST

240 242 244 246 248

24

26

28

30

32

34 JulAugSepOctNovDecSPOT

C. NOAA OIsst

240 242 244 246 248

24

26

28

30

32

34

D. Coastwatch Blended

240 242 244 246 248

24

26

28

30

32

34

Longitude (E)

240

242

244

246

248

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Light onlyRey noldsOIsstBlended

SPOTLight CISST CI

Latitude (N)

22

26

30

34

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

16

18

20

22

24

SST (C)

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Rey noldsOIsst

BlendedTag SST

Latitude

( N)

Longitude ( E) Date

1. Swirl – General sense; Track segments are colored by month

3. Taste – Understand SST, see how SST gradient matters

2. Sip – Snip out segments, look at confidence interval (shaded)

+ “True” positions (SPOT/GPS)

Yellow line

A. Light only

240 242 244 246 248

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26

28

30

32

34

B. Reynolds SST

240 242 244 246 248

24

26

28

30

32

34 JulAugSepOctNovDecSPOT

C. NOAA OIsst

240 242 244 246 248

24

26

28

30

32

34

D. Coastwatch Blended

240 242 244 246 248

24

26

28

30

32

34

Longitude (E)

240

242

244

246

248

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Light onlyRey noldsOIsstBlended

SPOTLight CISST CI

Latitude (N)

22

26

30

34

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

16

18

20

22

24

SST (C)

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Rey noldsOIsst

BlendedTag SST

Latitude

( N)

Longitude ( E) Date

Mako 1901

C.

A.

D.

B.

A. Light only

240 242 244 246 248

26

28

30

32

34

36

B. Reynolds SST

240 242 244 246 248

26

28

30

32

34

36JulAugSepOctNovDecSPOT

C. NOAA OIsst

240 242 244 246 248

26

28

30

32

34

36

D. Coastwatch Blended

240 242 244 246 248

26

28

30

32

34

36

Longitude (E)

240

242

244

246

248

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Light onlyRey noldsOIsstBlended

SPOTLight CISST CI

Latitude (N)

26

30

34

38

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

16

18

20

22

24

26

SST (C)

Jul 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004

Rey noldsOIsstBlendedTag SST

Latitude

( N)

Longitude ( E) Date

Mako 39322

C.

A.

D.

B.

A. Light only

238 242 246 250

18

20

22

24

26

28

30

32

34

JulAugSepOctNovDecJanFebSPOT

B. Reynolds SST

238 242 246 250

18

20

22

24

26

28

30

32

34

C. NOAA OIsst

238 242 246 250

18

20

22

24

26

28

30

32

34

D. Coastwatch Blended

238 242 246 250

18

20

22

24

26

28

30

32

34

Longitude (E)

240

242

244

246

248

Aug 2003 Oct 2003 Dec 2003 Feb 2004

Light onlyRey noldsOIsst

BlendedSPOTLight CI

SST CI

Latitude (N)

18

22

26

30

34

Jul 2003 Sep 2003 Nov 2003 Jan 2004 Mar 2004

14

16

18

20

22

24

SST (C)

Jul 2003 Sep 2003 Nov 2003 Jan 2004 Mar 2004

Rey noldsOIsstBlendedTag SST

Latitude

( N)

Longitude ( E) Date

Mako 1902

C.

A.

D.

B.

A. Light only

192 196 200 204

12

14

16

18

20

22

24

26

28

30

B. Reynolds SST

192 196 200 204

12

14

16

18

20

22

24

26

28

30

SepOctNovDecJan

FebMarAprMaySPOT

C. MODIS Aqua

196 197 198 199 200 201

18

20

22

24

D. Coastwatch Blended

196 197 198 199 200 201

18

20

22

24

Longitude (E)

194

196

198

200

202

Sep 2002 Nov 2002 Jan 2003 Mar 2003 May 2003

Light onlyRey nolds

ModisBlended

SPOTLight CI

SST CI

Latitude (N)

15

20

25

30

Sep 2002 Nov 2002 Jan 2003 Mar 2003 May 2003

22

24

26

28

30

SST (C)

Sep 2002 Nov 2002 Jan 2003 Mar 2003 May 2003

Rey noldsModisBlendedTag SST

Latitude

( N)

Longitude ( E) Date

Drifter

C.

A.

D.

B.

Download

http://www.soest.hawaii.edu/tag-data/software/

• R (2.8 and below)– NOT 2.9.0 (latest, released April, 2009)

– A basic internal R function has changed for unzipping

• Let us know when– it works!

– it doesn’t…

– You have

• Double-tag data

Chi Lam USC

Acknowledgements

This work was sponsored by the Pelagic Fisheries Research Program, University of Hawaii.

We thank Michael Musyl, Suzanne Kohin, David Holts, Dave Foley, Wildlife Computers, and Lotek Wireless for generously sharing data and ideas.

NASA Earth System Science Fellowship

Cheers!