LEXPLORE PLATFORM

LéXPLORE Letters No. 15

This newsletter was generated on the 14-03-2023.

The figures below are showing data for the period 21-02-2023 to 07-03-2023.

Until today, Thetis sampled 3382 depth profiles on Lake Geneva. In this Newsletter we show 38 profiles, so just 1.12% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

After a period of rather high air temperatures and small rain showers, lasting until the 25th of February, atmospheric conditions changed drastically. A stormy weather front brought high wind speeds and waves with low air temperatures. Afterwards, clear sky conditions resulted in high daily air temperature amplitudes with chilly nights going into March.

The lake water column responded accordingly. After the period of positive water temperature and Chlorophyll A anomalies ended, we recorded the wind-induced mixing of the water column on the 26th and 27th of February. Concurrently, we see a flip of the anomaly signals, with positive temperatures and Chlorophyll A anomalies deeper in the lake. The following cold atmospheric temperatures then cooled down again the top layers of the lake, marking colder than normal conditions for the surface lake layers at the beginning of March.

Side note: The precipitation events around the 24th of February left a small response in the backscattering observations, generated by small particles from the runoff streams.

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, 15, https://lexplore.info/wp-content/uploads/2023/03/lexplore-letters-2023-03-14.html