2019-2021

Figure 23 - Temporal evolution of air temperature (ºC). It follows a parabolic curve (in relation to the cycle of the height of the sun on the horizon) with maximums in the rainy period (November - February) and minimums in the dry period (June - August). It fluctuated between 0.1 ºC and 17.1 ºC, with an average of 9.6 ºC. It can be noted that on the surface of the lake the air temperature does not freeze (does not pass negative). During the dry season the daily thermal amplitude is greater (range up to 16 ºC) than in the rainy season (range up to 9 ºC).

Figure 24 - Temporal evolution of atmospheric pressure (barometric; in mm Hg). During the dry and wet seasons, it ranged between 482 and 489 mm Hg, with a period of 2-3 days and an average of 485 mm Hg. The daily amplitude is +/- 3 mm Hg, with slightly lower pressures in the transition season (December).

Figure 26 - Time evolution of the average wind direction (in 5 min intervals) (º). The wind that usually starts blowing in the afternoon changes direction daily at 360 º. [To be included] 

Figure 27 - Temporal evolution of relative air humidity (%) over the two years. At the beginning of the rainy season (November), as well as during the windy period (July-August) during the dry season, the daily amplitude was higher (~11-95 %), than during the wet period (January-February, 40-80 %). During the two years, relative humidity fluctuated between a minimum of 10 and a maximum of 95 %, with an average of 63 % and a median of 65 %. Slightly, during the 1st semester, the amplitude of variation was higher in 2020 compared to 2021. During the 2nd half of the year, the amplitude of variation in 2019 was greater than in 2020.

Figure 28 - Temporal evolution of precipitation (rainfall) during two years between 2019 and 2021. Rainfall (storms) occurred mostly between November and February, and was most intense (up to 8 and 11 mm/5 min) and frequent in late January and late November. Visually, the patterns of the years were quite similar. During the 1st half of the year, 2020 appears slightly more rainy than 2019. During the 2nd semester, apparently 2019 and 2020 were quite similar. Statistical time series analysis is needed to verify if the differences are significant.

Figure 29 - Temporal evolution of hailstorm during two years between mi-2019 and mi-2021. Hailstorms were very scarce. They occurred mainly between November and March, although very sporadically and of reduced intensity/duration. The maximum recorded occurred at the end of March 2021 with 0.9 impact/cm2.

Figure 30 - Time evolution of incident visible solar radiation during the two years. The Li-COR Li-200R pyranometer measures global solar radiation, i.e. the combination of direct and diffuse solar radiation, in the range 400 to 1100 nm, in W/m2. This equipment was only installed on the buoy on 08/29/2020. The radiation oscillated between a minimum in the dry season (June-July; < 300 W/m2) and maximums in November-February (≥ 400 W/m2), with oscillations of 2-3 weeks. It  had an average (between day and night periods) of 89 W/m2 and a median of 13 W/m2. The maximum reached 548 W/m2. This intense solar radiation is responsible for generating the thermal winds with daily frequency.