Recycling of water in the Amazon Basin: An isotopic study

Abstract

The oxygen‐18 content of precipitation in the Amazon basin is characterized by a very small inland gradient, 0.75 × 10−3 ‰ km−1. This is a consequence of the large contribution of reevaporated moisture to the basin's water balance. A distinct seasonal and regional pattern of stable isotope composition has been recognized and shows the basin to be inhomogeneous from the hydrometeorological point of view. The occasional appearance of very low δ values is believed to be related to the position of the ITCZ rather than to interbasin processes.

Huascaran δ18O as an indicator of tropical climate during the Last Glacial Maximum

“…To match the annual average composition of -17 o /oowe fix the precipitation height at the mean of the seasonal extremes (6300m) and take r = .4 . This is close to runoff estimates based on streamflow and precipitation data [Moreira et al, 1997;Salati et al, 1979].…”

Composição isotópica da água de chuva e da água do solo em floresta amazônica do tipo terra firme, região de Manaus

“…Salati et al (1979) verificaram que o conteudo de 8 18 0 das precipitac;:6es na Bacia Amazonica e caracterizado por um gradiente de 0,75 x 10-3 0 / 00 /km em consequencia da umidade reevaporada. Sequndo esses autores ce~ ca de 44% da umidade deixa a bacia na forma de vapor, sendo a quantidade restante, recirculada na pr6pria bacia.…”

Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra

“…To draw inferences about these lower tropospheric processes, many studies have so far relied on the isotopic composition of precipitation (e.g., Salati et al, 1979;Gat and Matsui, 1991;Tian et al, 2001). However, precipitation is strongly affected by post-condensation processes that blur the original vapor signal (Stewart, 1975;Lee et al, 2008;Risi et al, 2008).…”

“…In the lower troposphere, the water vapor isotopic composition is sensitive to the origin of water vapor and precipitation, such as continental recycling (Salati et al, 1979;Gat and Matsui, 1991) or air mass origin (Tian et al, 2001). To draw inferences about these lower tropospheric processes, many studies have so far relied on the isotopic composition of precipitation (e.g., Salati et al, 1979;Gat and Matsui, 1991;Tian et al, 2001).…”