LEXPLORE PLATFORM

LéXPLORE Letters No. 59

This newsletter was generated on the 19-11-2024.

The figures below are showing data for the period 29-10-2024 to 12-11-2024.

Until today, Thetis sampled 4754 depth profiles on Lake Geneva. In this Newsletter we show 29 profiles, so just 0.61% of the recorded data. The complete data set is available at Datalakes.

Data highlights of this issue

After a calm, high air pressure October with minimal amounts of wind and precipitation, the atmospheric situation slowly changes. Air temperatures start to drop below maxima of 10 deg;Celsius and autumns winds are picking up.

In the waters below the platform, we see a decreasing temperature gradient between deeper and upper lake layers, an expected development going into the European winter. Interestingly, the temperature anomaly pattern shown in previous newsletters seems to resolve itself. Cold surface anomalies are slowly changing towards neutral conditions over the span of the two weeks shown here. That leaves the integral of the temperature anomalies across all depth layers to be positive, with most of the heat still stored below 25 meters.

Chlorophyll A and oxygen production is also expected decrease in this part of the year, but the Chlorophyll anomalies clearly indicated an unusually low amount of Chlorophyll in the waters below the platform, especially after the strong wind forcing events on November 11th and 12th.

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, 59, https://lexplore.info/wp-content/uploads/2024/11/lexplore-letters-2024-11-19.html