Results of temperature measurements at lake Nokoué

10/11/2019

Reporter Katrijn Baetens

The team got back to the lake the 11th of November to pick up the thermometers left at the three stations. The one at the yatch club unfertunately was not sealed properly, so no data could be retrieved. Also the one at the west of the lake did not provide us with good data, here the issue was a malfunctioning of the thermocouple itself. The data logger in the center gave results for 7 days, the light was not switched on when retrieved, this sensor used rechargeable batteries.

The results of the 6 day temperature measurements:

 

Temperature evolution in the center of lake Nokoué Benin, Oct 2019
Average daily temperature and precipitation in Cotonou October 2019

From the results it is clear that their is mostly a clear day-night cycle observed in the surface temperatures of the lake except during the night of 17 and 18 October. The average temperatures of the atmosphere in the region did not explain why there was a decrease in overall surface temperature, an increased precipitation rate could have induced the observed temperature drom. Further research is necessary.

Our first experiences with the Arduino based equipment are good, however, to compete with the professional equipment , a better solution for powering the device should be found. Also proficient care should be given to sealing up the system and making sure the sensor is properly working.

Reanalysis of the first results

Sunday 13th of October 2019

After 10 busy days full of working and adjusting our work, we finally managed to make the temperatures measured at the port presentable and in a good format.

After ten days of hard work the team (Zacharie, Katrijn, Sylvain, Wilfried, Medard and field expert Victor) finally have the confidence to test there sensors in the field

After reanalysing the data of 3 and 4 October and comparing them with the GPS shield output we can come up with the following results:

Results of the sensor left at the port of Cotonou

The conclusion of these measurements is that the system is too unstable to produce good results and the gps module uses a lot of battery. After removing the GPS module and stabilizing the system we found the following results:

The conclusion of these measurements is that the addition of shock absorbers  proved very beneficial, there was one power cut that happened during the recollection of the system. The results can be positioned in time in a reliable manner.

On monday, when we will analyse the results gathered during the weekend, we will see if these conclusions can be hold in a real experimental set up.