| dc.description.abstract | The páramo ecosystem is characterized by a very moist climate and the continuous presence of fog
and low-intensity rainfall. The most important páramo feature is the high water regulation capacity
which in part might be related to the high frequency of fog and low-intensity rainfall (drizzle).
Therefore, it is essential to understand the hydrological processes that are linked to the ecology of
the páramo. This study aimed the following three objectives: (1) to assess fog water estimates
derived from three different types of fog gauges, and from them to understand its temporal
dynamics and the importance of fog to annual rainfall; (2) to quantify the contribution of fog water
deposition to soil moisture; and (3) to analyze the impact of fog on evapotranspiration rates, under
different weather conditions (clear, foggy and rainy). Findings of this study show that fog occurs at
very low intensities (0.2 mm h-1) reporting events of short term (<3 hours) at wind velocities below
4 m s-1. Most of the time fog appears combined with other type of precipitation (i.e. drizzle, light
rain or rain) with fog tending to be more intense in the early morning, and at night. On average,
daily fog amounts 1.37 mm. Overall, fog and drizzle are the major water sources to páramo
vegetation, especially during late night-time and early mornings, when evaporation is low. The fog
water deposition shows that only 4.5% of fog reaches the soil, contributing to soil moisture changes
rather low (0.1-0.2 mm), whilst the combination of fog with low-intensity rainfall generate a higher
contribution on soil moisture (as high as 4.3 mm). These events are potentially important for both
soil moisture and stream flow, because of their long duration and high total amount per-event. Daily
evapotranspiration rates are reduced by 43% due to the presence of mixed conditions (fog + lowintensity rainfall) compared with clear conditions (no fog and no rainfall). The net radiation is
reduced by 9.2% during foggy conditions (only fog) mainly because its early morning hours
occurrence is higher, and when solar radiation peaks fog occurrence is lower. While, during mixed
conditions the net radiation is reduced by 33%. At the same time as less humid periods were
reported, evapotranspiration was also low; suggesting that fog and drizzle presence can inhibit
transpiration, limit water loss by evaporation and also could alleviate water stress. | |
