LEXPLORE PLATFORM

LéXPLORE Letters No. 52

This newsletter was generated on the 13-08-2024.

The figures below are showing data for the period 23-07-2024 to 06-08-2024.

Until today, Thetis sampled 4591 depth profiles on Lake Geneva. In this Newsletter we show 54 profiles, so just 1.18% of the recorded data. The complete data set is available at Datalakes.

Jul 242024Jul 27Jul 30Aug 2Aug 5−50−40−30−20−10Jul 282024Aug 4−50−40−30−20−10Jul 242024Jul 27Jul 30Aug 2Aug 5−50−40−30−20−10Jul 242024Jul 27Jul 30Aug 2Aug 5−50−40−30−20−10Jul 242024Jul 27Jul 30Aug 2Aug 5−50−40−30−20−10Jul 282024Aug 4−50−40−30−20−10Jul 242024Jul 27Jul 30Aug 2Aug 5−50−40−30−20−10Jul 282024Aug 4051015202530
Wind SpeedAir TemperatureWave HeightDaily Rainfall10152025[deg C]−4−2024[K]891011[mg/L]708090100110120[%]12345[μg/L]−1−0.500.51[μg/L]0246[1.e-2 m-1]TimeTimeTimeTimeTimeTimeTimeTimeDepth [m]Depth [m]Depth [m]Depth [m]Depth [m]Depth [m]Depth [m][deg C], [mm], [m/s] & [dm]TemperatureTemp. Anomaly wrt daily climatologyDissolved OxygenOxygen SaturationChlorophyll AChl. A Anomaly wrt daily climatologyBackscattering 700 nmAir Temp., Rainfall, Wind Speed and Wave Height

Data highlights of this issue

Happy Birthday LéXPLORE Letters! We are happy to bring you two years of continuous data highlights from the platform!

In this issue, we have a look at the recordings from end of July to the beginning of August. We can see that phytoplankton activity is pumping oxygen into the lake, even though phytoplankon anomalies are nothing extraordinary. Only at the beginning of August, when high temperatures coincide with low wind conditions, that is when positive Chlorophyll A anomalies start to form in the upper layers of the lake.

Interestingly, water temperature anomalies show a three pole pattern, where the surface layers are warmer than usual, followed by a very cold layer between 5 and 20 meters depth, with anomalies of up to -4 Kelvin. Further down below, many days highlight another layer with positive temperature anomalies. Puzzling!

We also recorded a storm pass by on the night of Switzerland´s national holiday, mixing up the water column, shuffling cold water to the surface and reducing phytoplankton activity.

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, 52, https://lexplore.info/wp-content/uploads/2024/08/lexplore-letters-2024-08-13.html