LEXPLORE PLATFORM

LéXPLORE Letters No. 48

This newsletter was generated on the 18-06-2024.

The figures below are showing data for the period 28-05-2024 to 11-06-2024.

Until today, Thetis sampled 4409 depth profiles on Lake Geneva. In this Newsletter we show 53 profiles, so just 1.2% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

In this issue, we continue to see plenty precipitation recorded, but the event with the biggest impact happened around May 30th and 31st. Strong winds and waves, created by what looks like an atmospheric front passing by the platform, together with high precipitation sums, shuffled the water column down to considerable depth.

Temperature, chlorophyll and backscattering recordings all indicate a mixture of the water column down to 40 meters depth and more. Together with the slightly weaker wave event on June 6th, we can see the impacts of this wind forcing also in the anomaly plots. The water temperature anomalies are patchy, going from positive to negative temperature anomaly depth gradients from one day to the other. This is a results of warm surface waters being shuffled downwards, and colder water masses shuffled towards the surface. That said, the Chlorophyll A anomalies show mostly negative values. In order for phytoplankton to accumulate, weak wind and rain forcing together with strong temperature forcing are favorable. Whereas we recorded warm enough air temperatures, the lakes´s near-surface layers seemed to be too disturbed for a substantial phytoplankton accumulation.

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, 48, https://lexplore.info/wp-content/uploads/2024/06/lexplore-letters-2024-06-18.html