# Presentation: 531578

## Fish LIDAR

- A proposed technology transfer plan from ETL to NMFS
- James Churnside
- OAR Environmental Technology Laboratory

**Notes:**
The purpose of this brief is to describe a path to NOAA operational implementation of the OAR Fish lidar and related instrumentation.

## Strategic Goal

- Ecosystem-Based Management
-    “With our partners, we will monitor and observe fish species, protected resources, and ocean, coastal, and Great Lakes ecosystems and communities to provide basic information on habitats and the human activities that affect them.”

**Notes:**
ETL is pursuing this research in direct support of the first goal of the NOAA Strategic Plan.

## The Challenge

-    How to increase ecosystem Monitoring and Observing capabilities to allow us to effectively Understand and Describe; Assess and Predict; Engage, Advise and Inform; and Manage
-    This is particularly important for historically under-observed components like forage fish, juvenile fish, and zooplankton.

**Notes:**
In a move from species-specific management to ecosystem-based management, increased monitoring and observations will be required for ecosystem components for which there has not been a large monitoring effort.  Phytoplankton is not included in this list because of satellite-based estimates of primary productivity, although more information on smaller scales than provided by satellite data may still be required.  

## The Opportunity

-    Existing and emerging technologies will soon allow a wide range of ecosystem components to be observed over a wide range of spatial and temporal scales using a combination of satellites, aircraft, ships, AUVs, and moorings.

**Notes:**
The exciting opportunity in ecosystem observations and monitoring is not the emergence of a single sensor, but the combination of sensors on different platforms to allow measurements to be made over the full range of important temporal and spatial scales.

## The Vision

-    For each region, an integrated ecosystem observing system uses data from all available platforms to monitor and observe all important components of the local ecosystem.
-    ETL is concentrating on the development of airborne capabilities for this system that will be transferred into routine use.

**Notes:**
Regional ecosystem observing systems, combined with appropriate ecosystem models will allow true ecosystem management.  For reasons described below, ETL has determined that the greatest payoff on an investment in sensor technology is in the area of airborne instrumentation.

## Observing System Platforms

**Notes:**
Final observing system uses satellites, aircraft, ships, and moorings to observe ecosystem on all important scales.

## Characteristics - Satellites

- Cost – Huge capital investment, but the data are generally available either free or at very low cost to the user.
- Coverage – Global, with revisit times of days.  Spatial resolution is relatively poor, with several 100 m to 1 km typical.
- Data Quality – Limited, with chlorophyll *a* concentration, sea-surface temperature, and sea-surface height the most common ocean parameters available.

**Notes:**
Satellite data will be critical to the integrated ecosystem observing system of the future, but there is a huge capital cost to bring a new sensor into operational use.  Also, there is a large global effort in this area already, so we have decided that this is not the area where we can have the greatest impact.

## Characteristics – Ships, AUVs, Moorings

- Cost – High capital investment and high operating costs.
- Coverage – Global, but practically must be limited to an area that can be surveyed before it changes.  Spatial resolution can be as small as desired.
- Data Quality – Best available, limited only by the quality of sensor and sampling technologies available.

**Notes:**
As with satellites, there is a significant capital investment for new sensors.  In this case, the cost is directly related to the slow speed of ships; a relatively large number of ships must be equipped with new technology to have an impact.  Also, there is already a large effort, and this is not  the area where we can have the greatest impact.

## Characteristics - Aircraft

- Cost – Relatively low. Only a few systems are needed, surveys do not take long to complete.
- Coverage – Global. Near-shore regions (EEZ) can use smaller aircraft and are therefore less expensive.
- Data Quality – Intermediate. Spatial resolution much better than satellite, but not as good as ship.

**Notes:**
The costs for improved airborne instrumentation are relatively low because of the short time required for a survey.  This means that the operating costs for each survey are relatively low.  It also means that only a few systems are needed to perform all of the required surveys, and the acquisition cost is relatively low.  The resolution and data quality fill a gap between those of satellite instruments and of ships, AUVs, and moorings.  The amount data currently collected by ship is much less than is possible with current and emerging sensors.  These factors combine to provide an opportunity for ETL to make a significant contribution in this area at a modest cost.

## Survey Cost Comparison

- Ship – assume a cost of $12000/day and a survey speed of 5 kts = $100/mile
- A 20-day survey covers 2400 miles at a cost of $240K
- Plane – assume a cost of $700/hour and a survey speed of 140 kts = $5/mile
- 2400 miles can be covered twice in 6 days for $24K
- The total cost of an adaptive survey with the same ship covering half of the lidar survey area would be $144K

**Notes:**
This slide makes some reasonable assumptions about ship and aircraft speed and costs.  This shows that the aircraft is much less expensive than the ship.  The combined cost of an aerial survey combined with a shorter surface survey is still much less than the aerial survey and dominated by ship costs.  The ship is used for ground truth for the lidar data, and the lidar data are used to direct the ship to the portion of the survey area of greatest interest. 

## Aerial Data Currently Used

- Visual observations of marine mammals and turtles – often from NOAA Twin Otter aircraft.
- Visual observations of fish schools – generally from spotter pilots working for the fishing industry.  This source of data seems to be decreasing.

**Notes:**
While both NOAA and private aircraft are used for 

## Aircraft Instruments Available Now

- Thermal radiometer for sea-surface temperature  that provides information on ocean thermal structure.  Instruments are commercially available, but some work on calibration and validation is required for this specific application.
- Visible radiometer for ocean color, which can produce chlorophyll *a* estimates.  Also commercially available, but a calibration and validation effort is required.

**Notes:**
Commercially available thermal and visible radiometers are available for aircraft use.  They are fairly inexpensive (~$10-20K) and easy to mount in most aircraft.  There are questions of calibration and of retrieval validation for airborne use, especially for the visible radiometers.  One nice feature of these instruments is that they provide the same information as satellite instruments, but with better spatial resolution, nearer to the shore, and on the same time scales as visual observations.

##  Instruments Requiring Development

- Microwave radiometer for sea-surface salinity – has been demonstrated, but requires improved sensitivity and engineering for operational use.
- Fish LIDAR – has been demonstrated, but requires validation under more conditions and engineering for operational use, including data processing algorithms.

**Notes:**
NOAA NOS has used an airborne salinity mapper for coastal studies, but it is still an experimental apparatus, and needs some engineering refinement for routine use.  Also, improved sensitivity is required for open ocean applications where the salinity variations are smaller.
Fish LIDAR has been used by OAR on an experimental basis, showing excellent agreement with traditional surveys under a variety of applications.  Further validation, engineering refinement, and improved data processing algorithms are required.

## Microwave Salinity Radiometer

- Passive microwave imaging of sea surface salinity with applications in coastal circulation forecasting, and prediction of primary production and invasive species such as sea nettles.
- Coastal salinity gradients and presence of small land features and shoreline preclude microwave imaging of estuarine salinity from satellites - airborne surveying is essential.
- Microwave salinity mapping technology is mature enough for development of prototype operational systems, with eventual operation from UAVs.

## Microwave Mapping of Salinity

- Actual Microwave Salinity Map:  Provides enhanced resolution and improved   specificity of salinity Data can be used to initialize salinity models

- NOS Salinity Model based on PORTS Data

## PSR/L Scanning Antenna Concept

-  Sea surface salinity maps with ~0.2-0.8 psu sensitivity and ~1 km
-   surface resolution over ~50 x 100 km region in ~3-4 hours
-  Uses thin rotating disk antenna to improve on SLFMR design
-  Single narrow-beam dual-polarized conical scan uses front and back
-   looks at a constant 45o incidence angle to minimize errors
-   caused by beam switching in original SLFMR system
-  Compatible with existing ETL PSR system to accommodate flight testing
** **First test article antenna built by Ball Aerospace ATC (2002)
-  Flight qualified version under design study – first possible flight 2004

## Fish LIDAR

- Adult fish – images of large fish or density profiles of small schooling fish near surface.
- Juvenile fish – density profiles of juvenile fish, including some species where the adults are too deep for lidar.
- Zooplankton – density profiles of zooplankton, even in phytoplankton bloom.

**Notes:**
Fish LIDAR has been tested experimentally for these applications.

## LIDAR Image of Salmon

**Notes:**
In the imaging mode, individual salmon near the surface can be identified.  These were in the top 2 m of the water column.  The flight altitude was 150 m.

## Photo and LIDAR Profile of Mullet

**Notes:**
Dense schools of small fish very close to the surface can be profiled.  This was a school of mulled within the top 2 m of the water column.

## Lidar vs Echosounder School by school comparison of adult fish

- R = 0.994

**Notes:**
The correlation between lidar and echosounder for surface schools like the one in the previous slide was extremely high when the same schools were measured by both.  (The aircraft located the schools and directed the boat with the echosounder to come and measure the same school.)

## Zooplankton, Prince William Sound

- LIDAR

- Echosounder

**Notes:**
Distributions of zooplankton were measured by echosounder over a 3-day period and by lidar 2 days later in 8 areas of the Sound.

## Lidar vs Echosounder 

- Lidar vs Echosounder

- Correlation coefficient *R* as a function of the threshold level *T* applied to the LIDAR signal.  Applying a threshold to the lidar signal separates the zooplankton return from the ubiquitous by lower phytoplankton return, to obtain a correlation of 0.78.  Zooplankton was almost all *neocalanus*.

**Notes:**
A high correlation was obtained once the lidar were thresholded to remove the component from phytoplankton.  Target strength measurements of neocalanus and other zooplankton species is required to set the threshold level objectively and to infer number density and biomass from the lidar signal.

## Lidar vs Echosounder

- Correlation coefficient *R* for various values of threshold *T* and filter length *L* used to select the return from juvenile pollock near Kodiak Alaska.  This is a comparison of the daytime acoustic return with the nighttime lidar return.

**Notes:**
While adult pollock are generally too deep to be effectively surveyed by lidar, juveniles come to the surface at night.  The appropriate combination of spatial filtering of the data and thresholding removes phytoplankton and zooplankton contributions and produced a good correlation with echosounder results on a transect by transect basis.  We are continuing the analysis of these data on smaller spatial scales.

## Technology Transfer – Stage 1

-    Integrate a package with thermal and visible radiometers into the NOAA Twin Otter.  This is a very low-cost ($35K) implementation that will provide sea-surface temperature and primary productivity on visual surveys of marine mammals and turtles on the same spatial and temporal scale as the animal counts.

**Notes:**
Transfer of airborne technology to operational use should proceed in a 4-stage process.  Stage 1 applies commercial instruments to flights that are already planned.  Local data will allow the distribution of animals to be understood in the context of the temperature and primary productivity structure of the ocean.

## Technology Transfer – Stage 2

-    Apply fish lidar to fisheries research questions to develop the confidence in the capabilities and limitations of the technique that is a prerequisite for management applications.  This is the path to operations that fisheries acoustics followed, and it seems to be a good model to follow.

**Notes:**
Stage 2 would apply fish lidar to ongoing fisheries research problems to help understand ecosystem dynamics and also to fully test the capabilities of fish lidar to the point where the data can be used for management purposes.

## Technology Transfer – Stage 3

-    Add the microwave radiometer for salinity and the fish lidar for zooplankton and forage fish to the NOAA Twin Otter package.  This provides a significant amount of information about the ecosystem as long as there is some ground truth information available about fish and zooplankton species composition.

**Notes:**
Stage 3 adds microwave and lidar to the Twin Otter package.  The full package, including observers, would provide information on marine mammals, turtles, sea birds, individual large fish, schools of adult commercial species like sardine and herring, schools of adult forage species like capelin and sandlance, juveniles of a wide variety of species, zooplankton, phytoplankton, suspended sediment load, turbidity, temperature and salinity.

## Technology Transfer – Stage 4

-    Spin off technology to private industry from which NOAA and other organizations can contract specific surveys using private aircraft.  This is similar to the model that has been used by the SHOALS airborne lidar bathymeter.  The choice between the NOAA and contract systems would depend on the survey requirements.

**Notes:**
Stage 4 leads to a commercial survey capability to supplement the Twin Otter.  The number of systems available would depend on the level of use by NOAA, State Fish and Game departments, etc., and would be developed in response to demand without a large capital investment by NOAA.

## 4-Stage Timeline

|          FY: | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |   |   |   |   |   |   |   |
|  Stage 1: |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |
|  Stage 2: |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |
|  Stage 3: |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |
|  Stage 4: |   |   |   |   |   |   |   |   |   |   |

|   | Instrument Development |
| --- | --- |
|   |   |
|   | Transition |
|   |   |
|   | Routine Operational Use |

- Sea-surface temperature, chlorophyll

- Fish lidar

- Sea-surface salinity, fish lidar, temperature, chlorophyll

- Commercial surveys

**Notes:**
The timeline assumes continued OAR investment of about 2 FTEs and a similar investment by other organizations.  Note that Stage 2 does not directly lead to an operational mode, but feeds into Stage 3 and 4 products.