2023-2024

Air temperature vary widely within a 10 ºC daily range.

Barometric pressure can increase or drop up to 6 mm Hg in a few days.

Relative humidity can fluctuate between 30 and 100 % daily. 

Incident solar radiation can reach 450 Watt/m2, as measured within the 400-1100 nm range (Li-COR LI-200R pyranometer). The average incident solar radiation across the entire earth is ca. 240 W/m2.

It seems that it rained almost continuously during the last weeks, yet too little. It is clearer from the 24-hrs graph.

Winds that blow in the afternoons are very strong, up to 14 m/s, i.e. 50 km/h.

The daily air temperature range is wide, up to 8-10 ºC. Surprisingly, peaked above 18 ºC on Dec. 25. As it doesn't rain, under a clear sky solar radiation is strong, thus warming the lake surface. Thus, Lake Titicaca is really a sentinel of climate change. It also responds quickly to meteorological changes. Thus, evaporation can reach 9 mm/day, as maximum daily value according to historical calculations. 

These barometric pressures are higher that the 474 mm Hg expected at 3800 m a.s.l. at 15 ºC. What happens with an increase in atmospheric pressure? Does it affect the evaporation rate? This needs to be studied. This effect may have been underestimated until now. Possibly, since long term calculus have been done on a monthly time step. Thus, this high frequency help us to understand better the mechanisms.

Daily relative humidity span widely between 30 and 90%. 

Incident energy of solar radiation bewteen 400 and 1100 nm, measured with a Li-COR LI-200R pyranometer.  The 500 Watt/m2 as daily maximum are close to historical values. There are various methods to estimate cloudiness. Most use n/N where n is surface incident radiation, and N is the incident radiation at the top of the atmosphere, i.e roughly 1361 W/m2.

A daily precipitation of 20 mm/24 hrs corresponds to the typical maximum values during December, which is a good news. Until now, we didn't see torrential rains necessary for the lake level to increase towards the average level (1810 m a.s.l.). Yet, we will got the definitive response in March, since the January and February rains are crucial. 

Average daily wind speed is 6 m/s (22 km/h), and maximum up to 14 m/s (50 km/h) that is strong. Those thermal winds blow mainly during the afternoons. 

During a 24-hr period, wind direction rotates almost 360 º. The average direction from one day to the next changes dramatically.  

Air temperature range (ºC) - Fluctuated abruptly between 4 and 19 ºC, with a slight tendency to decrease (frequency 5 min). 

Air humidity range (%) - Humidity  fluctuated bwetween 20 and100 % with a slight tendency to increase (frequency 5 min). 

Solar radiation range (W/m2, 400-1100 nm) - Maximum fluctuated between 300 and 500 W/m2 (frequency 5 min). 

Rain events (mm/event) - The rains were sporadic (not every day) reaching more frequently 20 mm/day, with a maximum of 50 mm/day on 05/01/2024. During this 98-day period the cumulated rain was 480 mm. (frequency 5 min).

Wind speed range (m/s) - Fluctuated up to 14 m/s, i.e. 50.4 km/h. Typically, the wind (of thermic or atmospheric origine) blows mostly in the afternoon. 

Barometric pressure range (mm Hg) - It fluctuated between 481 and 489 mm Hg with no clear tendency. 

Hail events (hit cm-2 day-1) - Hail was very occasional and not intense (0.1-0.4 hit cm-2 day-1), and occurred only 7 times.