Browsing by Author "Berrones Guapulema, Gina Marcela"

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Assessment of fog gauges and their effectiveness in quantifying fog in the andean páramo
(2021) Célleri Alvear, Rolando Enrique; Wilcox, Bradford P.; Berrones Guapulema, Gina Marcela; Tobon, Conrado; Crespo Sánchez, Patricio Javier
In tropical highlands of the northern Andes, known as páramos, fog incidence is very frequent. Its quantification is not yet clear, mostly because of the complexity of distinguishing between fog and low-intensity rainfall. Moreover, there is uncertainty about the performance of the various types of gauges used to capture fog in this ecosystem. This study was carried out at the Zhurucay Ecohydrological Observatory (3,800 m a.s.l.), in southern Ecuador, assessing two cylindrical (Juvik and Wire Harp types) and two flat-screen fog collection gauges. A high-resolution laser disdrometer was installed next to the fog gauges, to measure precipitation of very low intensities and isolate fog from rainfall. We collected data over a 12-month period for four types of events—fog only, fog dominant, fog non-dominant and fog negligible. We evaluated the performance of the gauges during each type of event as well as to estimate the amount, rate and duration of fog. Fog was present during 68% of the days of the study, predominantly in the early morning and at night, and the average daily contribution was 1.37 mm. Most of the events occurred at rates below 0.3 mm h−1. Measured rainfall was 1,200.1 mm, and fog estimations amounted to 340.1 mm. This fog contribution could bring total annual precipitation to about 1,540.2 mm, suggesting an extra 22% of water potentially available to the ecosystem—a very important asset for hydrological and ecological processes. This is the first study that has compared different types of fog gauges in the Andean páramo
Fog in the Andean Páramo: measurements, dynamics, and its influence on soil hydrology and evapotranspiration processes
(Universidad de Cuenca, 2022-09-15) Berrones Guapulema, Gina Marcela; Célleri Alvear, Rolando Enrique
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.
Importance of Fog and Cloud Water Contributions to Soil Moisture in the Andean Paramo
(2022) Berrones Guapulema, Gina Marcela; Célleri Alvear, Rolando Enrique; Wilcox, Bradford P.; Ochoa Sánchez, Ana Elizabeth; Crespo Sánchez, Patricio Javier
Páramos are particular ecosystems of the Tropical Andes, where fog and low-intensity rainfall such as drizzle are commonly frequent—but the contribution of these water sources to soil water replenishment and discharge is not yet clear, mainly because the development of techniques for separating fog from drizzle and wind-driven rainfall has been challenging. Fog was measured with a cylindrical Juvik gauge and types of precipitation other than fog with a high-resolution disdrometer. Soil moisture was measured at 100 mm depth by means of Water Content Reflectometers, then Effective precipitation (EP) was calculated. We categorized events as two types: fog only (FO) and cloud water (CW). We found that in the case of FO events, only small amounts reached the soil (EP ranged between 0.1 and 0.2 mm); in contrast, greater amounts of EP originated from CW events (maximum value of 4.3 mm). Although we found that FO events are negligible for stream water contribution; they are ecologically important for maintaining high relative humidity, low net radiation, and consequently low evapotranspiration rates. Our research provides new insights into the hydrological role of fog, enabling us to better understand to what extent its input influences the water resources of the Andean páramo.
Variability in evapotranspiration in the Andean páramo as influenced by fog and rainfall
(2024) Berrones Guapulema, Gina Marcela; Crespo Sánchez, Patricio Javier; Carrillo Rojas, Galo José; Célleri Alvear, Rolando Enrique
Tropical mountains such as the páramos of the Andes, which serve as ‘water towers’ for local communities and downstream cities, are important areas for early detection of climate change. Here, fog and low-intensity rainfall are very common and play a key role in ecohydrological processes. Although evapotranspiration (ET) represents an important part of the water cycle, how ET and fog processes interact and how they affect páramo vegetation and water resources availability are poorly understood. This study investigated the effects of foggy (fog only) and mixed (fog and rainfall) conditions on ET. To determine whether fog significantly reduces ET, we compared ET and meteorological data under these two conditions with those during dry days. We found that on foggy days, when fog was most prevalent in the early morning, ET declined on average by 4% and net radiation (Rn) by 9.2%. Under mixed conditions, daily ET declined by 42% and Rn by 33%. In the páramo, where mean annual precipitation and ET are 1210 and 635 mm, respectively, the estimated annual reduction in ET due to fog and rainfall combined is between 77 and 174 mm. We found that during fog and rainfall mixed conditions, solar radiation was reduced, consequently constraining the energy available for ET while sustaining high relative humidity, ultimately reducing water loss. Our findings, which suggest that the presence of fog and low-intensity rainfall restricts water losses by evaporative demand, contribute to a better understanding of the ecohydrological importance of these water inputs in the Andes.