Module 4 Lab



In this Lab you will:

  • use Google Earth KML file of a system of tide gauges on the Permanent Service for Mean Sea Level (PSMSL) site to locate data from several tide gauges;
  • demonstrate your skill at accessing, analyzing, and interpreting data obtained from key tide gauges that give us a reliable, long term record;
  • extrapolate the observed data to make predictions about the potential for sea level change in the foreseeable future for these locations, considering local sea level rise as well as more regional or even global trends; and
  • compare and contrast sea level rise predictions for the same locations using a NOAA sea level rise viewer and several sea levels rise scenarios.

Lab Overview

There are two parts to this Lab. Part I: Analyzing Sea Level Change Using Tide Gauge Data and Part II: NOAA Sea Level Rise Viewer.

Part I: Analyzing Sea Level Change Using Tide Gauge Data

In Part I of this Lab, you will use data obtained from the Permanent Service for Mean Sea Level (PSMSL) in conjunction with Google Earth. A KML file is provided by the PSMSL site to open in Google Earth, making data access seamless. The sea level data are monthly and annual means referenced to a common benchmark and are referred to as Revised Local Reference (RLR). This type of data are used to create accurate time series to observe trends. We are choosing four tide gauges with long time series. The longer the time series (more data), the more reliable the data are for looking at trends in sea level. You will notice a great deal of short-term variability in the data – more in some locations than others. As you work through the lab, think about the difference between short-term and long-term time series data and the reasons for the short-term variability that makes the data “noisy."

PART II: NOAA Sea Level Rise Viewer

Sea level rise is expected to accelerate in the immediate future, but even using the annual rates you calculated from the tide gauge data from the 20th Century and early 21st Century, a steady rise would be expected.

In Part II of this Lab, you will use the NOAA Sea Level Rise Viewer to help you visualize what these levels would look like in particular locations around the U.S.

You will keep your calculated rates in mind for each place from Part I as you work with the viewer and consider the factors that influence the future projections of increased sea level rise.

NOAA built the viewer based on data that calculates a projected Global Mean Sea Level (GMSL) for 2100 to be between 0.3 m and 2.5 m. The model uses five GMSL rise scenarios: Intermediate-Low, Intermediate, Intermediate-High, High and Extreme, which correspond to GMSL rise by 2100 of 0.5 m, 1.0 m, 1.5 m, 2.0 m and 2.5 m, respectively (NOAA). For more detail on the science behind the Sea Level Rise Viewer, please take time to read at least the Executive Summary and Introduction of NOAA Technical Report NOS CO-OPS 083 “Global and Regional Sea Level Rise Scenarios for the United States” listed in Resources.


Directions for downloading tide gauge data using the PSMSL site and Google Earth

  1. Go to: PSMSL Tide Gauges.
  2. Follow the directions to download the tide gauge KML file and open in Google Earth.
  3. The PSMSL RLR Catalogue folder will appear in your Temporary Places in Google Earth. Click on this folder to open and select the Last Reported Year of 2016 or after (or most recent available). This will reveal the tide gauges around the world that have the most current data. These are the gauges we are interested in. We are also interested in those that have long and continuous datasets. We have chosen three that have good data available going back to early in the 20th Century. These are: Boston MA, San Francisco, CA, and Grand Isle, LA. They also provide us with U.S. northeast coast, west coast, and Gulf coast locations.


Before you begin the Lab, you will need to download the Lab worksheet and tide gauge data. We advise you to either print or download/save the Lab worksheet, as it contains the steps you need to take to complete the Lab in Google Earth. In addition, it contains prompts for questions that you should take note of (by writing down or typing in) as you work through the Lab.

Once you have worked through all of the steps and completed the measurements, you will go to the Module 4 Lab in Canvas to complete the Lab by answering multiple-choice questions. The answers to questions on this Lab worksheet will match choices in the multiple-choice questions in Canvas. Submit the quiz in Canvas for credit.