The significance of species segregation for Amazonian chemistry

H.G. Ouwersloot, J. Vilà-Guerau de Arellano, L.N. Ganzeveld, M.C. Krol, J. Lelieveld

Research output: Contribution to conferenceConference paperAcademic

Abstract

Tropical rain forest chemistry is driven by the exchange of biogenic compounds, dynamic processes like turbulent mixing and the diurnal variability of the atmospheric boundary layer. The segregation of species due to inefficient turbulent mixing has recently been recognized as a possible relevant dynamic influence that could explain the large discrepancies between observations and simulations of reactive trace gas concentrations over the tropical rain forest. The inability of turbulence to mix the species leads to correlated or anti-correlated accumulations of the reacting species, therefore modifying the boundary layer mean reactivity. In order to make observations comply with large scale model results, chemists currently assume ad hoc values of the intensity of segregation that correspond to a substantial decrease in the isoprene-OH reaction rate. We will present numerical experiments with a large-eddy simulation (LES) model that are based on typical dynamic and chemistry conditions in the Amazonian rain forest. With a chemistry module coupled to the LES, we examine the main processes that control the species segregation. Our results indicate that the influence of segregation is negligible in a typical situation for the Amazonian rain forest characterized by uniform emission conditions. Finally we will present the potential enhancement of segregation due to spatially heterogeneous surface emissions. In these simulations, spatial segregation is induced by introducing heterogeneities in the surface properties: a cold and wet forested patch characterized by high isoprene emissions is alternated with a warm and dry patch, representing pasture with relatively low biogenic emissions
Original languageEnglish
Pages1-5
Publication statusPublished - 2010
Event19th Symposium on Boundary Layers and Turbulence - Keystone, United States
Duration: 1 Aug 20106 Aug 2010

Conference

Conference19th Symposium on Boundary Layers and Turbulence
CountryUnited States
CityKeystone
Period1/08/106/08/10

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isoprene
turbulent mixing
large eddy simulation
boundary layer
biogenic emission
trace gas
reaction rate
simulation
pasture
turbulence
experiment
tropical rain forest
rain forest
cold

Cite this

Ouwersloot, H. G., Vilà-Guerau de Arellano, J., Ganzeveld, L. N., Krol, M. C., & Lelieveld, J. (2010). The significance of species segregation for Amazonian chemistry. 1-5. Paper presented at 19th Symposium on Boundary Layers and Turbulence, Keystone, United States.
Ouwersloot, H.G. ; Vilà-Guerau de Arellano, J. ; Ganzeveld, L.N. ; Krol, M.C. ; Lelieveld, J. / The significance of species segregation for Amazonian chemistry. Paper presented at 19th Symposium on Boundary Layers and Turbulence, Keystone, United States.
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abstract = "Tropical rain forest chemistry is driven by the exchange of biogenic compounds, dynamic processes like turbulent mixing and the diurnal variability of the atmospheric boundary layer. The segregation of species due to inefficient turbulent mixing has recently been recognized as a possible relevant dynamic influence that could explain the large discrepancies between observations and simulations of reactive trace gas concentrations over the tropical rain forest. The inability of turbulence to mix the species leads to correlated or anti-correlated accumulations of the reacting species, therefore modifying the boundary layer mean reactivity. In order to make observations comply with large scale model results, chemists currently assume ad hoc values of the intensity of segregation that correspond to a substantial decrease in the isoprene-OH reaction rate. We will present numerical experiments with a large-eddy simulation (LES) model that are based on typical dynamic and chemistry conditions in the Amazonian rain forest. With a chemistry module coupled to the LES, we examine the main processes that control the species segregation. Our results indicate that the influence of segregation is negligible in a typical situation for the Amazonian rain forest characterized by uniform emission conditions. Finally we will present the potential enhancement of segregation due to spatially heterogeneous surface emissions. In these simulations, spatial segregation is induced by introducing heterogeneities in the surface properties: a cold and wet forested patch characterized by high isoprene emissions is alternated with a warm and dry patch, representing pasture with relatively low biogenic emissions",
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Ouwersloot, HG, Vilà-Guerau de Arellano, J, Ganzeveld, LN, Krol, MC & Lelieveld, J 2010, 'The significance of species segregation for Amazonian chemistry' Paper presented at 19th Symposium on Boundary Layers and Turbulence, Keystone, United States, 1/08/10 - 6/08/10, pp. 1-5.

The significance of species segregation for Amazonian chemistry. / Ouwersloot, H.G.; Vilà-Guerau de Arellano, J.; Ganzeveld, L.N.; Krol, M.C.; Lelieveld, J.

2010. 1-5 Paper presented at 19th Symposium on Boundary Layers and Turbulence, Keystone, United States.

Research output: Contribution to conferenceConference paperAcademic

TY - CONF

T1 - The significance of species segregation for Amazonian chemistry

AU - Ouwersloot, H.G.

AU - Vilà-Guerau de Arellano, J.

AU - Ganzeveld, L.N.

AU - Krol, M.C.

AU - Lelieveld, J.

PY - 2010

Y1 - 2010

N2 - Tropical rain forest chemistry is driven by the exchange of biogenic compounds, dynamic processes like turbulent mixing and the diurnal variability of the atmospheric boundary layer. The segregation of species due to inefficient turbulent mixing has recently been recognized as a possible relevant dynamic influence that could explain the large discrepancies between observations and simulations of reactive trace gas concentrations over the tropical rain forest. The inability of turbulence to mix the species leads to correlated or anti-correlated accumulations of the reacting species, therefore modifying the boundary layer mean reactivity. In order to make observations comply with large scale model results, chemists currently assume ad hoc values of the intensity of segregation that correspond to a substantial decrease in the isoprene-OH reaction rate. We will present numerical experiments with a large-eddy simulation (LES) model that are based on typical dynamic and chemistry conditions in the Amazonian rain forest. With a chemistry module coupled to the LES, we examine the main processes that control the species segregation. Our results indicate that the influence of segregation is negligible in a typical situation for the Amazonian rain forest characterized by uniform emission conditions. Finally we will present the potential enhancement of segregation due to spatially heterogeneous surface emissions. In these simulations, spatial segregation is induced by introducing heterogeneities in the surface properties: a cold and wet forested patch characterized by high isoprene emissions is alternated with a warm and dry patch, representing pasture with relatively low biogenic emissions

AB - Tropical rain forest chemistry is driven by the exchange of biogenic compounds, dynamic processes like turbulent mixing and the diurnal variability of the atmospheric boundary layer. The segregation of species due to inefficient turbulent mixing has recently been recognized as a possible relevant dynamic influence that could explain the large discrepancies between observations and simulations of reactive trace gas concentrations over the tropical rain forest. The inability of turbulence to mix the species leads to correlated or anti-correlated accumulations of the reacting species, therefore modifying the boundary layer mean reactivity. In order to make observations comply with large scale model results, chemists currently assume ad hoc values of the intensity of segregation that correspond to a substantial decrease in the isoprene-OH reaction rate. We will present numerical experiments with a large-eddy simulation (LES) model that are based on typical dynamic and chemistry conditions in the Amazonian rain forest. With a chemistry module coupled to the LES, we examine the main processes that control the species segregation. Our results indicate that the influence of segregation is negligible in a typical situation for the Amazonian rain forest characterized by uniform emission conditions. Finally we will present the potential enhancement of segregation due to spatially heterogeneous surface emissions. In these simulations, spatial segregation is induced by introducing heterogeneities in the surface properties: a cold and wet forested patch characterized by high isoprene emissions is alternated with a warm and dry patch, representing pasture with relatively low biogenic emissions

M3 - Conference paper

SP - 1

EP - 5

ER -

Ouwersloot HG, Vilà-Guerau de Arellano J, Ganzeveld LN, Krol MC, Lelieveld J. The significance of species segregation for Amazonian chemistry. 2010. Paper presented at 19th Symposium on Boundary Layers and Turbulence, Keystone, United States.