Lidar Surveys

Jim ChurnsideNOAA Research

What is a lidar?

• Operates like an echosounder, except with a short laser pulse instead of a short acoustic pulse.

• Operates from a small aircraft instead of a surface vessel.

• Penetrates to over 50 m in clear water, 20-30 m in murky coastal water.

Two Installations

Piper Seminole NOAA Twin Otter

Lidargram - Nearshore

Lidargram - Offshore

Intercomparisons

• Intercomparisons have been made with acoustic and trawl surveys

• Species include sardine, anchovy, herring, capelin, mackerel, and mixed schools (“baitfish”)

• Correlations are high if lidar and surface surveys are close together (within about four days)

Plus Camera (or Video)

• Images increase swath width, but with limited depth penetration

• Images help to identify surface returns• Lidar helps to identify image features• Camera generally not useful at night

(exception is low-light-level camera when bioluminescence is present)

Aircraft flight tracks20 flightsNov. 3 – Dec. 10, 2010

26 hours, day21 hours, night

10 000 km (San Diego to Beijing)

818 schools

Proposed Surveys

• Coast-wide summer survey• Fall southern California survey

• Either should be coordinated with a surface survey.

Hake Survey

Survey example

2005 hake survey lines spaced by 10 nmi and extended from coastline to 50 m water depth.

US portion accomplished with about two months of ship time at 11-12 kts (15,000 nmi).

Aerial coverage would require about 100 hours

Adaptive Sardine Survey

Budget

• Coast-wide survey - $400K, including $140K aircraft costs, $250K labor and overheads (based on day and night coverage equivalent to two months of ship survey)

• Southern California Survey - $115K, including $35K aircraft costs, $75K labor and overheads (based on day and night coverage of CalCOFI +)

• These are total costs.

Questions

• What is the best mix of ship and aircraft time to estimate sardine abundance and distribution?

• Do we need to oversample with both in order to answer the first question?

Research Vessel Cost

R/V New Horizon is intermediate class at $20,000 per day, or $1,200,000 for 60 daysDoes not include scientific personnel.

Survey Salary

• GS-12, step 5, San Diego - $40 per hour• 24% benefits + 88% overhead - $85 per hour• 12 hour day – $1000 per day• 2 scientists for 60 days - $120,000• Scientific staff of 12 for 60 days - $720,000