Kelvin waves during GOAmazon and their relationship to deep convection
Serra, Yolande — University of Washington
Rowe, Angela K — University of Wisconsin
Area of research:
Atmospheric Kelvin waves are synoptic disturbances in winds, temperature, and moisture in the troposphere that are observed in satellite observations of deep cloud cover over the central Amazon. Our study uses data collected during the Observations and Modeling of the Green Ocean Amazon (GOAmazon) field campaign in 2014-15 to investigate how these Kelvin waves modulate the growth, type, and organization of convection over this region.
The influence of Kelvin waves on deep convection over the central Amazon has implications for improved predictability of organized weather systems in this region and for representation of convection and its growth on local to synoptic scales in global models.
This study aimed to improve understanding of the local and large-scale controls on convective development over the central Amazon. The results of this study demonstrate that Kelvin waves are strong modulators of synoptic-scale low-to-mid-level free-tropospheric moisture, integrated moisture convergence, and surface heat fluxes over the central Amazon. These regional modifications of the environment impact the local development and diurnal cycle of convection, favoring mesoscale convective systems to develop overnight and into the next morning for the convectively active wave phases. As a result, localized rainfall is also strongly modulated by Kelvin waves, with the majority of rainfall in the GOAmazon region occurring during the convectively active phase of the Kelvin wave passage.