Identification

Title

The role of boundary layer dynamics on the diurnal evolution of isoprene and the hydroxyl radical over tropical forests

Abstract

We investigate diurnal variability of isoprene and related chemical species in the Amazonian region. The dynamics and chemistry of an atmospheric boundary layer are studied with a large-eddy simulation code and a mixed-layer model which are guided by observations available for the same area. The main features of isoprene and related species are reproduced well, but their evolution raises questions regarding the physical and chemical processes responsible for the observed diurnal behaviors. To address these questions, we systematically examine the role of (1) the exchange of chemical species between the free troposphere and the atmospheric boundary layer (entrainment), (2) surface isoprene and nitric oxide emissions, and (3) new chemical pathways to recycle the hydroxyl radical. The entrainment flux of isoprene is shown to be equally important as surface isoprene emissions in determining the isoprene temporal evolution. Varying the relationship between the initial isoprene mixing ratio in the boundary layer and that in the overlying free troposphere in the early morning results in an 50% increase/decrease in isoprene mixing ratio or more within the atmospheric boundary layer at noon. Entrainment of free tropospheric nitrogen oxides creates changes of similar magnitude to the boundary layer isoprene mixing ratio. These effects of entrainment and surface emissions on isoprene are found for two different chemical regimes. The introduction of an OH recycling pathway in the chemical mechanism increases midday OH. Our findings show that atmospheric dynamics and chemistry are equally important for interpreting the diurnal observation of reactants and for including in regional-scale modeling efforts where turbulence is parameterized.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d79s1rnv

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2011-04-06T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact