Latent Heating Profiles over the Amazon in Relation to the Atlantic Walker Circulation
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The western rising branch of the local Walker circulation over the Atlantic intensifies as a result of enhanced convection and the associated latent heat release over the greater Amazon region. Monthly measurements gathered from 16 years of Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) data are used to construct a latent heating climatology, which is then compared to those generated by the Convective and Stratiform Heating (CSH), Spectral Latent Heating (SLH), and variational analysis algorithms, to determine methodological accuracy. Three-dimensional reflectivity measurements collected during the Green Ocean Amazon experiment (GOAmazon2014/5) by the Sistema de Proteção da Amazônia (SIPAM) S-band Doppler radar located in Manaus in the central Amazon are also used to calculate latent heating profiles, and are compared to local sounding budgets. While all of the methods show similar seasonal cycles of latent heating, there are notable differences in the magnitude and height of maximum heating. Years are then identified as having higher or lower heat release during the Amazon wet season in boreal spring. Sea-level pressure, sea surface temperature, and surface wind measurements over the equatorial Atlantic are analyzed to determine the relative effect of an enhanced rising branch of the Walker circulation using data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). Higher heating over the Amazon during the wet season generally strengthens the Walker circulation over the equatorial Atlantic during boreal spring and yields lower surface pressures, stronger easterlies, and a delayed cold tongue in the equatorial Atlantic during boreal summer. This work provides observational confirmation of a strong link between Amazonian heating and the Atlantic Walker circulation, which has implications for improving significant biases in global climate models over the Amazon and Atlantic and enhancing our understanding of how Amazonian rainfall links to tropical climate variability.
Monroe, Emily Elizabeth (2016). Latent Heating Profiles over the Amazon in Relation to the Atlantic Walker Circulation. Master's thesis, Texas A & M University. Available electronically from