LFA

COORDINATOR:

• Henrique Barbosa

AGENCY:

• Multiple projects supported the experiment

Rationale

Supporting Projects

(:title ACONVEX - Aerosols, Clouds, cONVection EXperiment (2011-2017):)

The concentration of water vapor in the tropics is highly variable in both time and space. Its vertical distribution above the boundary layer depends on slow advection and on the deep convection it self, which serves as the free troposphere’s water vapor source. At the same time, deep convection itself is sensitive to the distribution of humidity in the free troposphere, developing more vigorously in humid environments. Water vapor also plays an important role in enhancing the convective available potential energy (CAPE), which depends essentially on the boundary layer humidity, but also on the concentration of water in the free troposphere. While CAPE is constantly removed from the atmosphere by convection itself. Observations with high spatial and temporal resolution are necessary for a better understanding these complex interactions and feedback mechanisms between convection and humidity which occur in meso or smaller scales. Over the tropical regions, however, there are very few of such measurements particularly long-term ones allowing for a climatological perspective.

To overcome this lack of observations, a new experimental site was implemented near Manaus-AM, in the Brazilian Amazon Forest. The ACONVEX (Aerosols, Clouds, cONVection EXperiment) site will run continuously during the next years applying a synergy of different instruments.

In our Laboratory, the following research projects supportted the ACONVEX experiment:

See the site description here

[Sitios/Manaus-Embrapa|[See the site description here]]

The concentration of water vapor in the tropics is highly variable in both time and space. Its vertical distribution above the boundary layer depends on slow advection and on the deep convection it self, which serves as the free troposphere’s water vapor source. At the same time, deep convection itself is sensitive to the distribution of humidity in the free troposphere, developing more vigorously in humid environments. Water vapor also plays an important role in enhancing the convective available potential energy (CAPE), which depends essentially on the boundary layer humidity, but also on the concentration of water in the free troposphere. While CAPE is constantly removed from the atmosphere by convection itself.

Observations with high spatial and temporal resolution are necessary for a better understanding these complex interactions and feedback mechanisms between convection and humidity which occur in meso or smaller scales. Over the tropical regions, however, there are very few of such measurements particularly long-term ones allowing for a climatological perspective. To overcome this lack of observations, a new experimental site was implemented near Manaus-AM, in the Brazilian Amazon Forest. The ACONVEX (Aerosols, Clouds, cONVection EXperiment) site will run continuously during the next years applying a synergy of different instruments.

Research Projects

In our Laboratory, the following research projects are supporting the GoAmazon experiment:

1. The climatic effects of clouds in the radiative balance and hydrological cycle of the Amazon
   • Coordinator: Theotonio Pauliquevis
   • Agency: CNPq LBA, 458017/2013-2, 2014-2016
2. Cloud optical properties in the Amazon derived from ground and satellite based instruments
   • Coordinator: Henrique Barbosa
   • Agency: Capes, Ciência sem fronteiras, BJT A016_2013
3. GoAmazon: Interactions of the urban plume of Manaus with biogenic forest emissions in Amazonia.
   • Coordinator: Paulo Artaxo
   • Agency: FAPESP 2013/05015-0
4. Brazil-USA Collaborative Research: Modifications by Anthropogenic Pollution of the Natural Atmospheric Chemistry and Particle Microphysics of the Tropical Rain Forest During the GoAmazon Intensive Operating Periods (IOPs)
   • Coordinator: Henrique Barbosa
   • Agency: FAPESP/DOE/FAPEAM 2013/50510-5

Further information

(:title ACONVEX - Aerosols, Clouds, cONVection EXperiment:)

No contexto de mudanças climáticas, grandes incertezas residem na compreensão sobre como será a resposta das nuvens e da precipitação a um planeta mais impactado pela atividade antrópica. A região amazônica, por estar sujeita a um enorme gradiente de concentração de gases traço e aerossóis entre as estações chuvosa e seca, torna-se um excelente laboratório para o estudo das propriedades de nuvens tanto sob condição natural quanto sob esta forte influência humana.

Neste projeto, serão realizadas medidas de longo prazo para estudar as propriedades micro e macrofísicas de nuvens na região amazônica. Dentro os instrumentos que temos disponíveis, estão:

• radar de apontamento vertical,
• raman-lidar com canal de vapor de água,
• ceilômetro,
• contador de CCN,
• GNSS,
• fotômetro solar e
• radiômetro shadow-band,

que darão o detalhamento temporal e vertical necessários para se estudar a interação microfísica-nuvens-clima.

Também serão realizados estudos de modelagem numérica em alta resolução. Pretende-se utilizar o modelo BRAMS, desenvolvido pela comunidade brasileira e que conta hoje com a mais acurada representação da região amazônia do ponto de vista da vegetação, topografia, aerossóis e química. Entretanto, a parametrização de microfísica ainda é a original do RAMS, incluindo apenas um momento na distribuição de tamanhos e uma concentração fixa de CCN. Pretendemos implementar uma nova microfísica, como a do RAMS@CSU, que inclui CCNs dinâmicos com dois momentos e uma mistura de aerossóis (parâmetro kappa). A combinação de simulações e medidas permitirá entender melhor o ciclo de vida dos sistemas convectivos na região amazônica, bem como compreender os fatores que podem alterar os campos de nuvens e precipitação, e avançar no entendimento das interações aerossóis clima.