Collecting Data at a Station Using SonTek RSSL (Under Ice)

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Detailed Description

In this video we will outline the process of collecting an under ice station in the SonTek RSSL software. Note: Use of trade names is for descriptive purposes only, and does not imply endorsement by the USGS. For additional videos in this series, visit the following link: https://www2.usgs.gov/humancapital/ecd/hydrotube/hydrotube-ADCP.html
 

Details

Image Dimensions: 480 x 360

Date Taken:

Length: 00:03:05

Location Taken: Augusta, ME, US

Transcript

Hi my name is Nick Stasulis and I work with the Maine Office of the New England Water Science Center. In this video we will outline the process of collecting an under ice station in the SonTek RSSL software.

Immediately after you enter the edge information this dialog will appear that allows you to enter information associated with your first station. First, enter the distance from the initial point, which is essentially your distance from shore. You can also enter the distance between stations. Either way, ensure the location agrees with the location noted on your tagline. For ice measurements, ensure the water surface type is set to ice or ice and slush, depending on your conditions. If you are unsure, use ice and slush.

Notice that clicking in each of the ice information fields will change what is shown on the image to the right. Also understand that while the ice and slush information will make the graphs and displays in the software more useful, they are not used for computation purposes. If you decide to leave the ice information blank, only the transducer depth below the ice is needed, which should then match the transducer depth below water surface.

The use of user input water depth, the velocity correction factor and the island edge option will be discussed in separate videos outlining the process of entering a manual station and dealing with invalid depths.

Ensure a screening distance is entered here, which is equal to the transducer depth  plus 0.52 ft.  If the USGS screening feature was selected during software installation this will happen automatically. In this case our screening distance is equal to 0.72 ft as our transducer depth is 0.2 ft.  

For coordinate system, most ice measurements will use XYZ, which requires the ADCP be held at a fixed orientation to the tagline. This orientation is shown. ENU allows the ADCP’s compass to automatically account for flow angles based on the cross section azimuth, but should only be used as a backup method for ice conditions. A separate video in this series will discuss angle correction in more detail.

The default averaging time of 40 seconds should be used, though you may consider increasing this value in cases where you are getting intermittent invalid data.

Gage height information can be entered here, as well as the time the gage height was read. While there is an option to edit extrapolation methods here, those methods will usually be reviewed and applied during playback, a process described in a separate video in this series. You will notice that the extrapolation method is set to no slip/no slip when the water surface type of ice or ice and slush is selected.

If you are ready to end a measurement and enter ending edge information, select the End Edge button here. Once all fields are populated correctly, and you are sure that you are getting a reasonable number of valid depth cells and otherwise reasonable data, hit the Measure button, or select Enter to begin data collection.