LEXPLORE PLATFORM

LéXPLORE Letters No. 17

This newsletter was generated on the 11-04-2023.

The figures below are showing data for the period 21-03-2023 to 04-04-2023.

Until today, Thetis sampled 3485 depth profiles on Lake Geneva. In this Newsletter we show 59 profiles, so just 1.69% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

The data in this issue highlights the rollercoaster ride that happened below our platform at the end of March going into April.

A few days of milder temperatures with very little wind increased the surface water temperatures at the beginning of our two week period, after which stormier conditions with precipitation shuffled up colder, deeper water and unified the water column conditions from deeper levels throughout to the surface.

After this weather front passed through, warm and sunny spring conditions at the end of March warmed up the water column down to deeper levels. With fresh nutrients, from runoff and precipitation, and plenty of solar radiation, algae had perfect conditions to grow and increase the amount of Chlorophyll A in the water. This led to positive Chlorophyll A and water temperature anomalies for this time of the year.

Another storm at the beginning of April made this productive period seem more like a joke. High wind speeds and wave heights shuffled the water column again, bring up cold and nutrient poor water from deeper lake layers. The last days of the shown period indicate that the water column returns slowly to average spring conditions, with Chlorophyll A values still trailing behind water temperatures.

What is displayed

Data from the Thetis profiler:

  • Water Temperature in °Celsius

  • Water Temperature Anomaly on daily resolution with respect to to the available daily climatology from Thetis so far in Kelvin

  • Dissolved Oxygen mg/L

  • Oxygen Saturation in %

  • Chlorophyll A in μg/L

  • Chlorophyll A Anomaly on daily resolution with respect to to the available daily climatology from Thetis so far in μg/L

  • Backscattering of light 700 nm in 1.e-2 m-1, representing zooplankton or larger particles in the water

Data from the automatic weather station:

  • Air Temperature in °Celsius

  • Wind Speend in m/s

  • Precipitation in mm

Data from the wave buoy:

  • Wave height in decimeter

Authorship and further information

This newsletter is created by EPFL, specifically Martin Wegmann.

For more information about LéXPLORE, contacting us and possibilities to visit the platform: lexplore.info

If you want to know more about the Chlorophyll distribution across Lake Geneva, have a look at the satellite data map by our colleagues at CIPEL.

If you want to know more about the water temperature distribution across Lake Geneva, have a look at the lake reanalysis and forecasts by our colleagues at EAWAG.

If you want to use figures from the LéXPLORE Letters, you can use the following citation:

EPFL, Limnology Center 2023: LéXPLORE Letters, 17, https://lexplore.info/wp-content/uploads/2023/04/lexplore-letters-2023-04-11.html