The SIO Glider Program

The underwater glider ‘Spray’

Operations in AOSN 2003

Objectives: data for model assimilation; technical development

0 to 400 m vertical average velocity interesting

T data good but need higher vertical resolution

CTD, Optical Backscatter, Fluorometer all suffer from biofouling

Scales are 25 km and 2 days, shorter than we planned for

~ 400 m

~2.5 km Five gliders for 5 weeks uninterrupted

Operate 5 ~100-km offshore sections

Speed ~25 km/day ~0.5 knot

Profile to 400 m or 3 m from bottom

Cycle takes ~3 hours

0-400m

0-200m

August 2003 Glider Array

Velocity – Days 214-224

Fouling Is The Limit to DurationIn AOSN II five Sprays operated 35 days using 20% of their battery energy

All five optical (backscatter/fluorometer) sensors failed from fouling

CTDs were erratic as a result of biofouling

Even if sensors work, fouling will eventually degrade gliding performance

Scales of Variability

LT

Scales longer at surface – Offshore variation unknown

On average L ~ 25 km T ~ 2 days

MURI 2005Preparations

Test new CTD and short-range ADCP in San Diego

Improve and simplify the AOSN 2004 quality-control process and provide web access

Develop web-based software to simplify control and to guard against errors in issuing mission changes

2005 Field Trial:

Verify that bio-fouling problems under control

Gather statistical info (scales, tide energy, etc.) needed to plan 2006 experiment.

Use adaptive control to control scale-measuring array

MURI 2006

4 Sprays with CTD and ADCP (U(z), T(z), S(z))

Use software for 24/7 maintenance of the array to maximize mapping skill will be available (in collaboration with Princeton)

Gliders can be used to map mesoscale while investigating:

1. Mixing (Thorpe Scale) and relation to Richardson Number

2. Mixing and advection by internal tides

3. Mixed layer response to winds in upwelling

4. Accuracy of acoustic propagation predictions?