Light level geolocation

Michael SumnerPhD. candidate

Summary

• Light level geolocation

– Light data

– Environmental data

– Behavioural model

• Summarizing behaviour of multiple animals

• Calibrating tags

Tracking vertebratessouthern elephant seal

(male 5yo)

Photo:

J. van den Hoff, AAD

• Archival tag– Light level

– pressure (depth)– temperature– Archived on board

Light levels and solar elevation

Kingston, Tasmania April 2003

Time GMT

10 PM 8 AM 6 PM 2 AM 10 AM

8 AM 4 PM

Local time

LONGITUDE

time of noon in GMT

LATITUDE

length of day vs. night

LATITUDE

difference in length

of day versus night

Effect of longitude on expected light Effect of latitude on expected light

Locations for predicted light levels

DAWN DAWN

Light data – with solar elevation in Hobart (different y-scale)

Light data – choosing “twilight”

Real light data – diving elephant seal

Parameters to estimate – lon, lat, and light attenuation

Location estimates

• Storing series of estimates for animal “tracks”

Calibrating light tags