Thermohaline Circulation - Exploration2

Your Objective

How does the ocean temperature change by season and how is that change represented at different depths?

Make a prediction about how the temperature changes as you go deeper into the water column.
Make a prediction about how the temperature change at depth compares to that at the surface.

Specify CTD depths to plot:

30m 90m 350m 1000m

Show:

Model Air Temperature

Download this Dataset

Data Tips

When the site loads, you are able to see the full dataset of wind speed, seawater temperature, and seawater density for the POR of 2014-09-21 to 2018-06-17 from the Irminger Sea Flanking Mooring B and ECMWF reanalysis grid point. You can interact with the data by:

Turning on and off the various layers of temperature, density, and speed. If a reference layer is needed, I suggest the ECMWF wind speed OR the 30m temperature.
Zoom in and out of the data to highlight particular sections of the seasonal cycle. Site loads with all data highlighted, change highlighted width with zoom.

Questions for Thought

Orientation Questions

What oceanic and atmospheric variables are displayed in the graphs? What are the units associated with each variable?
What time period does the graph cover?
- What is the starting date?
- What is the ending date?
- How many complete years of data are represented?
What graph type is this?

Interpretation Questions

What changes or patterns did you observe in the temperature graphs at each depth?
At the surface, what month has the highest temperatures and what month has the lowest temperatures? What is the range of temperatures (highest - lowest) observed?
As you go deeper in the water column does the highest and lowest observed temperatures occur in the same months as at the surface?
Calculate the temperature range for the 90m, 350m, and 1000m depths.
Examine the temperature ranges for the surface and each depth. What happens to the range as you move deeper into the water column?

Background Information

Click on the images below to learn more about where and how the dataset above was collected.

Dataset Information

The data for this activity was obtained from the following CTDs on the Irminger Sea Flanking Mooring B:

Recovered datasets were downloaded from the OOI data portal, and then daily (mean) averages of temperature and density were calculated and merged together into a single file. Potential temperature and potential density were calculated using the seawater toolbox.

Because the meteorological data from the Irminger Surface Mooring is rather sparse, wind speed and air temperature data was obtained from the ECMWF reanalysis at the closest grid points (between 59-61°N and 40-38°W).

The highlighted boxes represent those time periods where the difference between the 350m and 30m potential density is less than 0.05 kg/m³. This effectively highlights those time periods when the mixed layer depth reaches far below the surface.

See this Jupyter Notebook for details on how the data for this activity was processed.

Activity Citation: Dixon, R., Beaird, N., & Lichtenwalner, C. S. (2019). Thermohaline Circulation. OOI Data Labs Collection.