LEXPLORE PLATFORM

LéXPLORE Letters No. 21

This newsletter was generated on the 06-06-2023.

The figures below are showing data for the period 16-05-2023 to 30-05-2023.

Until today, Thetis sampled 3690 depth profiles on Lake Geneva. In this Newsletter we show 51 profiles, so just 1.38% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

End of May we see the lake below our platform being impacted by yet another wind-induced mixing event. The windy episode of May 17th/18th was shuffling up cold water to the surface layers. We can see an incredibly cold water temperature anomaly for this time of the year of around -4 Kelvin close to the surface on May 18th/19th. But the mixing did not only have an impact on the water temperature.

At the same time we can see rather negative Chlorophyll A anomalies, reflecting the reduced Chlorophyll A concentration in the water masses that were shuffled towards the surface. With that, oxygen concentration is low as well. The impact of this mixing event continues for a few days as air temperatures slowly increase towards the end of May. Nevertheless, for this time of the year, we see more negative than positive water temperature and Chlorophyll A anomalies. We will see how this changes with warmer temperatures in June.

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, 21, https://lexplore.info/wp-content/uploads/2023/06/lexplore-letters-2023-06-06.html