• Wizard Island

    Crater Lake

    National Park Oregon

The CTD water monitoring sensor packages

A CTD is an instrument used in oceanography that contains multiple sensors attached to a single unit. The CTD is attached to a cable that is raised and lowered in the water column. Visit this site for additional information on CTD's.

Crater Lake owns two CTD units, one unit is deployed from the research boat Neuston and the other unit is permanently moored in the lake and takes a top to bottom measurement once per day.

 
ctd water monitoring sonde

A CTD sonde ready for lowering into Crater Lake.

NPS

  • Lowered from the water surface to the bottom (580 meters)
  • Takes readings twice per second
  • Stores readings while being lowered and data is downloaded afterwards on the boat
  • Measures:
    • water temperature
    • depth
    • salinity
    • particle density
    • chlorophyll concentration
 
CTD deployment

NPS

Crater Lake biologists prepare the CTD for deployment by turning the power on and cleaning the sensor heads.

Getting the CTD ready for deployment.

 
The CTD being deployed from the Neuston.

NPS

The CTD sensor package is visible about 15 feet below the boat.

The CTD is being lowered from the R/V Neuston on a wire winch.

The unit is approximately 5 meters (15 feet) under the boat in the picture.

 
Chlorophyll distribution in Crater Lake
NPS
A graph of chlorophyll concentrations and distribution in Crater Lake for July 2010 - January 2011.  These data were collected with our CTD that is permanently moored in the lake.  This CTD travels from the surface to the bottom and back once per day.
 
particle density in Crater Lake
NPS
A graph of particle concentrations and distribution in Crater Lake for July 2010 - January 2011.  These data were collected with our CTD that is permanently moored in the lake.  This CTD travels from the surface to the bottom and back once per day.

Did You Know?