LEXPLORE PLATFORM

LéXPLORE Letters No. 41

This newsletter was generated on the 12-03-2024.

The figures below are showing data for the period 20-02-2024 to 05-03-2024.

Until today, Thetis sampled 4159 depth profiles on Lake Geneva. In this Newsletter we show 31 profiles, so just 0.75% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

This February 2024 was the warmest February in Switzerland since the records started in 1864. This exceptional heat is now also stored in the Swiss water bodies and we can see it in our observations below and above the platform.

Most strikingly, water temperature anomalies throughout the water column are very much dominated by positive values, with positive anomalies of up to +0.6 Kelvin. That means, the lake is overall too warm for this season. A short window of negative anomalies at the lake surface, starting at the 22nd of February, was triggered by a strong precipitation, wind and wave event at the same day. With wave heights up to 1 meter, colder water from deeper levels was shuffled towards the surface.

At the beginning of March, warm temperatures, together with fresh nutrients and calm wind conditions, were the perfect conditions for phytoplankton growth, visible in the positive chlorophyll A anomalies starting around March 1st.

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 Speed 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 2024: LéXPLORE Letters, 41, https://lexplore.info/wp-content/uploads/2024/03/lexplore-letters-2024-03-12.html