On the Climate Impact of the Local Circulation in the Itaipu Lake Area

Abstract

The impact of the Itaipu Lake on the climate and local circulation is investigated here using the meteorological information available in the area. The Itaipu Lake is an artificial water reservoir of 1460 km 2 (approximately 170 km by 7.5 km), formed in 1982 as part of the Itaipu Power Plant. It is situated on the Brazil-Paraguay frontier, in the central portion of Parana River Valley. The analysis of the available meteorological data (air and water temperatures, air relative humidity, precipitation and radiosonde soundings) provides observational evidences supporting the hypothesis that the Itaipu Lake presence has an important impact in the local circulation, inducing a local circulation with lake breeze characteristics showing horizontal wind divergence over the lake during daytime and convergence during nighttime. From the regional point of view, the Itaipu Lake formation has reduced the thermal amplitude of the diurnal air temperature cycle. The precipitation data, investigated here, has not indicated any systematic effect associated to the lake formation. The reason for the apparent inconsistency is that others phenomena (e.g., valley-mountain circulation and El Niño events) could be masking the impact of the lake formation on the rain deficit in the region.

Itaipu reservoir limnology: eutrophication degree and the horizontal distribution of its limnological variables

“…The inspection of the topographical map of Itaipu valley (Stivari et al, 2005), suggests that the topography of the transition zone favours a flow increasing (Tucci, 2002), maximising the contribution of allochthonous material to the reservoir. In the terrestrial area adjacent to the transition zone there are numerous rural properties with rearing pigs and their waste are discarded / washed away without any treatment.…”

Effects of changes in land use on the diurnal temperature range: a long-term data analysis

“…In tropical dams, the increase in the minimum air temperature and the decrease in the maximum air temperature follow the same trend, although the diurnal range remains almost constant throughout the year (Stivari et al 2005). In the subarctic Great Lakes, the minimum air temperature increased throughout the year, although the winter maximum air temperature decreased, and the diurnal range was larger in summer than in winter (Hinkel and Nelson 2012).…”

“…Sacks et al (2009) reported that irrigation changed the local air temperature by increasing evaporation. Additionally, several explanations have been offered regarding the effect of dam lakes on the local climate from observational studies (Stivari et al 2005). In Ghana, downstream of the Akosombo Dam, the air temperature changed as the river flow decreased (Gyau-Boakye 2001).…”

“…For instance, an artificial lake promotes the occurrence of fog (Vogel and Huff 1975). Using observational data, it was shown that the Itapúa Dam, located in a subtropical zone, decreased the daytime air temperature and increased the nighttime air temperature five years after its construction (Stivari et al 2005). Chikamori and Kamii (1993), however, reported that there was no significant air temperature change before and after the construction of a dam located in a temperate region based on temperature data that spanned decades.…”

Analysis of local wind induced by surface heterogeneity and sloping terrain near Nakdong river

“…Sun et al (1997) investigated diurnal and seasonal variations of lake-induced atmospheric circulation over three lakes by using aircraft observation data. Stivari et al (2005) analyzed local circulation in a lake area by using available meteorological data. These studies examined local circulations induced by water bodies with width of a few kilometers.…”