5,7,2,- 1Università degli Studi di Milano, Department of Earth Sciences "Ardito Desio", Milano, Italy (luca.mortarini@unimi.it)
- 2Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, (mauricio.meteorologia@gmail.com)
- 3Universidade Federal de Santa Maria (UFSM), Department of Physics, Santa Maria, Brazil
- 4Technical University of Munich (TUM), Land Surface–Atmosphere Interactions (LSAI), Freising, Germany
- 5Institute for Climate Change Solutions, Urbino, Italy
- 6University of Oklahoma, School of Meteorology, Norman, OK, USA
- 7Max Planck Institute for Biogeochemistry, Biogeochemical Processes, Jena, Germany
Convective cold pools (CCPs) are a key driver of transient turbulence and rapid reorganization of the planetary boundary layer (PBL), strongly modulating surface–atmosphere exchanges. At the Amazon Tall Tower Observatory (ATTO) in central Amazonia, CCPs occur nearly daily and represent a dominant mechanism of boundary-layer disturbance. Using the detection framework of Oliveira et al.(2026), which identified 410 CCP events between August 2021 and December 2023, we investigate how CCP-induced changes in CO2, sensible heat, and momentum fluxes depend on cold-pool intensity and pre-existing PBL stability.
CCPs are first classified by intensity based on their minimum temperature anomaly, and subsequently by pre-CCP stability, which controls the background thermodynamic structure and CO2 storage within the forest canopy. Composite time–height analyses reveal a coherent dynamical structure during CCP passage, characterized by a narrow leading-edge updraft followed by a broader region of postfrontal subsidence and enhanced turbulence, consistent with a rotor-like circulation at the cold-pool front.
The scalar response is dominated by the postfrontal phase. After CCP arrival, cold-air advection and turbulent mixing lead to strong negative sensible heat fluxes, indicating downward transport of heat. At the same time, CO2 concentrations increase near the surface and extend upward, accompanied by positive CO2 fluxes, demonstrating the upward transport of CO2-rich air from within and below the canopy. These results suggest that ventilation is not dominated by the brief frontal ascent, but is primarily associated with enhanced turbulent mixing in the postfrontal wake.
The magnitude of these responses strongly depends on pre-existing stability. Under stable conditions, where CO2 accumulates near the surface due to weak mixing and respiration dominates, CCP-induced turbulence leads to the largest increases in CO2 concentration and flux. In contrast, under unstable conditions, the pre-existing mixed state reduces the impact of CCPs on scalar redistribution.
Overall, our results show that CCPs act as an efficient mechanism for redistributing scalars in the Amazon PBL, primarily through postfrontal turbulent mixing rather than frontal lifting. This highlights the importance of cold-pool dynamics in modulating biosphere–atmosphere exchange and provides new insights into the coupling between convective processes and ecosystem fluxes in tropical forests.
Oliveira, M. I., Mortarini, L., Acevedo, O. C., Cely-Toro, I. M., Grosso, M., Reis, L. I., Junior, C. Q. D.,
Quesada, C. A., Ribeiro, B. Z., and Brondani, D. V. (2026). Convective cold pools and attendant
turbulence at the amazon tall tower observatory (atto). Atmospheric Research, 327:108351.
How to cite: Reis, L. I., Oliveira, M. I., Ferreira, V., de Vargas Brondani, D., Acevedo, O., van Asperen, H., Q. Dias-Junior, C., and Mortarini, L.: The Role of Convective Cold Pools in the Transport of Carbon Dioxide over the Amazon Tall Tower Observatory (ATTO), EMS Annual Meeting 2026, Utrecht, Netherlands, 6–11 Sep 2026, EMS2026-420, https://doi.org/10.5194/ems2026-420, 2026.
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