Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory

Oliveira, Maurício I.; Acevedo, Otávio C.; Sörgel, Matthias; Lima Nascimento, Ernani de; Manzi, Antônio Ocimar; Oliveira, Pablo E.S.; Brondani, Daiane V.; Tsokankunku, Anywhere; Andreae, Meinrat O.

Artigo

Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory

In this study, high-frequency, multilevel measurements, performed from late October to mid-November of 2015 at a 80m tall tower of the Amazon Tall Tower Observatory (ATTO) project in the central state of Amazonas, Brazil, were used to diagnose the evolution of thermodynamic and kinematic variables a...

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Autor principal:	Oliveira, Maurício I.
Outros Autores:	Acevedo, Otávio C., Sörgel, Matthias, Lima Nascimento, Ernani de, Manzi, Antônio Ocimar, Oliveira, Pablo E.S., Brondani, Daiane V., Tsokankunku, Anywhere, Andreae, Meinrat O.
Grau:	Artigo
Idioma:	English
Publicado em:	Atmospheric Chemistry and Physics 2020
Assuntos:	Atmospheric Convection Boundary Layer Kinetic Energy Moisture Transfer Rainforest Thermodynamics Turbulent Flow Amazonas Brasil Manaus
Acesso em linha:	https://repositorio.inpa.gov.br/handle/1/15463

id	oai:repositorio:1-15463
recordtype	dspace
spelling	oai:repositorio:1-15463 Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory Oliveira, Maurício I. Acevedo, Otávio C. Sörgel, Matthias Lima Nascimento, Ernani de Manzi, Antônio Ocimar Oliveira, Pablo E.S. Brondani, Daiane V. Tsokankunku, Anywhere Andreae, Meinrat O. Atmospheric Convection Boundary Layer Kinetic Energy Moisture Transfer Rainforest Thermodynamics Turbulent Flow Amazonas Brasil Manaus In this study, high-frequency, multilevel measurements, performed from late October to mid-November of 2015 at a 80m tall tower of the Amazon Tall Tower Observatory (ATTO) project in the central state of Amazonas, Brazil, were used to diagnose the evolution of thermodynamic and kinematic variables as well as scalar fluxes during the passage of outflows generated by deep moist convection (DMC). Outflow associated with DMC activity over or near the tall tower was identified through the analysis of storm echoes in base reflectivity data from an S-band weather radar at Manaus, combined with the detection of gust fronts and cold pools utilizing tower data. Four outflow events were selected, three of which took place during the early evening transition or nighttime hours and one during the early afternoon. Results show that the magnitude of the drop in virtual potential temperature and changes in wind velocity during outflow passages vary according to the type, organization, and life cycle of the convective storm. The nocturnal events had well-defined gust fronts with moderate decreases in virtual potential temperature and increases in wind speed. The early afternoon event lacked a sharp gust front and only a gradual drop in virtual potential temperature was observed, probably because of weak or undeveloped outflow. Sensible heat flux (H) increased at the time of the gust front arrival, which was possibly due to the sinking of colder air. This was followed by a prolonged period of negative H, associated with enhanced nocturnal negative H in the wake of the storms. In turn, increased latent heat flux (LE) was observed following the gust front, owing to drier air coming from the outflow; however, malfunctioning of the moisture sensors during rain precluded a better assessment of this variable. Substantial enhancements of turbulent kinetic energy (TKE) were observed during and after the gust front passage, with values comparable to those measured in grass fire experiments, evidencing the highly turbulent character of convective outflows. The early afternoon event displayed slight decreases in the aforementioned quantities in the passage of the outflow. Finally, a conceptual model of the time evolution of H in nocturnal convective outflows observed at the tower site is presented. © Author(s) 2020. 2020-05-14T14:27:41Z 2020-05-14T14:27:41Z 2020 Artigo https://repositorio.inpa.gov.br/handle/1/15463 10.5194/acp-20-15-2020 en Volume 20, Número 1, Pags. 15-27 Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ application/pdf Atmospheric Chemistry and Physics
institution	Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional
collection	INPA-RI
language	English
topic	Atmospheric Convection Boundary Layer Kinetic Energy Moisture Transfer Rainforest Thermodynamics Turbulent Flow Amazonas Brasil Manaus
spellingShingle	Atmospheric Convection Boundary Layer Kinetic Energy Moisture Transfer Rainforest Thermodynamics Turbulent Flow Amazonas Brasil Manaus Oliveira, Maurício I. Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
topic_facet	Atmospheric Convection Boundary Layer Kinetic Energy Moisture Transfer Rainforest Thermodynamics Turbulent Flow Amazonas Brasil Manaus
description	In this study, high-frequency, multilevel measurements, performed from late October to mid-November of 2015 at a 80m tall tower of the Amazon Tall Tower Observatory (ATTO) project in the central state of Amazonas, Brazil, were used to diagnose the evolution of thermodynamic and kinematic variables as well as scalar fluxes during the passage of outflows generated by deep moist convection (DMC). Outflow associated with DMC activity over or near the tall tower was identified through the analysis of storm echoes in base reflectivity data from an S-band weather radar at Manaus, combined with the detection of gust fronts and cold pools utilizing tower data. Four outflow events were selected, three of which took place during the early evening transition or nighttime hours and one during the early afternoon. Results show that the magnitude of the drop in virtual potential temperature and changes in wind velocity during outflow passages vary according to the type, organization, and life cycle of the convective storm. The nocturnal events had well-defined gust fronts with moderate decreases in virtual potential temperature and increases in wind speed. The early afternoon event lacked a sharp gust front and only a gradual drop in virtual potential temperature was observed, probably because of weak or undeveloped outflow. Sensible heat flux (H) increased at the time of the gust front arrival, which was possibly due to the sinking of colder air. This was followed by a prolonged period of negative H, associated with enhanced nocturnal negative H in the wake of the storms. In turn, increased latent heat flux (LE) was observed following the gust front, owing to drier air coming from the outflow; however, malfunctioning of the moisture sensors during rain precluded a better assessment of this variable. Substantial enhancements of turbulent kinetic energy (TKE) were observed during and after the gust front passage, with values comparable to those measured in grass fire experiments, evidencing the highly turbulent character of convective outflows. The early afternoon event displayed slight decreases in the aforementioned quantities in the passage of the outflow. Finally, a conceptual model of the time evolution of H in nocturnal convective outflows observed at the tower site is presented. © Author(s) 2020.
format	Artigo
author	Oliveira, Maurício I.
author2	Acevedo, Otávio C. Sörgel, Matthias Lima Nascimento, Ernani de Manzi, Antônio Ocimar Oliveira, Pablo E.S. Brondani, Daiane V. Tsokankunku, Anywhere Andreae, Meinrat O.
author2Str	Acevedo, Otávio C. Sörgel, Matthias Lima Nascimento, Ernani de Manzi, Antônio Ocimar Oliveira, Pablo E.S. Brondani, Daiane V. Tsokankunku, Anywhere Andreae, Meinrat O.
title	Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
title_short	Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
title_full	Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
title_fullStr	Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
title_full_unstemmed	Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
title_sort	planetary boundary layer evolution over the amazon rainforest in episodes of deep moist convection at the amazon tall tower observatory
publisher	Atmospheric Chemistry and Physics
publishDate	2020
url	https://repositorio.inpa.gov.br/handle/1/15463
_version_	1787141763019833344
score	11.755432

Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory

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