Eddy-covariance CO2 fluxes over Itaipu lake, southern Brazil

Abstract

In this work, we present CO2, latent heat and sensible heat fluxes measured over the reservoir of the Itaipu Hydroelectric Power Plant (Paraná State, Brazil) during 2013. A tower was installed at a small island in the reservoir, where an Eddy Covariance system, with supplementary equipments and analysers, was deployed. The objective of this work was to determine the magnitude of CO2 fluxes and their variation throughout the year. CO2 flux displayed seasonality: in warm months there was a predominance of negative CO2 daytime fluxes and positive CO2 nighttime fluxes, which we attributed to photosynthesis/respiration in the reservoir; in cold months there was a predominance of negative CO2 fluxes in both periods, with CO2 air concentration apparently imposing the signal of the CO2 fluxes and the strong winds intensifying them. The range of 90% of the CO2 fluxes measured in this work (−102.68 to +151.72 µg m−2s−1 at the 30-min. time scale) is comparable to those observed in natural lakes and reservoirs around the world. On the average, the reservoir acted as a source of CO2, with an overall mean flux of +12.78 µg m−2s−1.

Salt marsh-atmosphere CO2 exchanges in Patos Lagoon Estuary, Southern Brazil

“…This result agrees with our findings and supports the idea that the plant's physiology is the major driver of the vegetation/atmosphere CO 2 fluxes. During the cold season, however, Armani et al (2020) found that both daytime and nighttime CO 2 fluxes were predominantly negative, suggesting an imposition of the atmosphere's CO 2 concentration and the occurrence of stronger winds on the CO 2 fluxes. The authors also reported that 90% of the CO 2 flux measurements made in their study area ranged between -102.68 to 151.72 mmol m -2 s -1 .…”

STAEBLE: A Surface‐Temperature‐ and Available‐Energy‐Based Lake Evaporation Model

“…Of course, it is not impossible to perform in‐lake measurements, as the early studies at lakes Hefner and Mead showed (G. E. Harbeck et al., 1958; USGS, 1954); several such studies at important lakes around the world have been conducted since then (e.g., Armani et al., 2020; Assouline & Mahrer, 1993; Blanken et al., 2000; Cancelli et al., 2012; M. T. Moreo & Swancar, 2013; Omar & El‐Bakry, 1981). In this work, we concentrate on the particularly long 5‐year data set generated by the recent USGS Lake Mead study initially reported by M. T. Moreo and Swancar (2013).…”