Coastal Influences On Pollution Transport
Author(s)
D. Peake, H. Dacre & J. Methven
Abstract
The ventilation of pollutants from the boundary layer into the free troposphere
is an important process in controlling regional air quality. Coastal outflow is the
horizontal ventilation of pollutants across a coastline from a layer within the
continental boundary layer to above the marine boundary layer. It has been shown
using the Met Office Unified Model that the ventilation by coastal outflow occurs
with a similar order ofmagnitude to ventilation by convection, and that it possesses
a diurnal cycle induced by the boundary layer height cycle over land. Pollutants
with short lifetimes (typically several hours) exhibit the greatest diurnal variability
in export by coastal outflow. Ventilation by coastal outflow by pollutants with
longer lifetimes are less dependent on the boundary layer height over land and
more dependent on the large scale cross-coastal wind strength. A simple model
developed to simulate coastal outflow shows that increasing the pollutant lifetime,
wind speed or convective boundary layer height increases export of tracer by
coastal outflow. Above a threshold windspeed, coastal outflow is reduced due to
tracer being exported across a coastline before being able to be mixed to a height
greater than the marine boundary layer. Convection slightly decreases export by
coastal outflow, although this effect is small.
Keywords: coastal outflow, pollution, modelling, coasts, tracer, ventilation, export
boundary layer.
1 Introduction
The vertical ventilation of pollutants from the boundary layer to the free
troposphere through convection and frontal mechanisms has a significant impact
on regional air quality [1, 2] and has been extensively studied [3–5]. The prospect
of horizontal ventilation across a discontinuity in boundary layer height, such as
one present at a coastline, has received relatively little attention [6]. During the
Keywords
coastal outflow, pollution, modelling, coasts, tracer, ventilation, export
boundary layer
Related Book
Other papers in this volume
Warning (2)
: foreach() argument must be of type array|object, null given [in
/var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/templates/Papers/view.php, line
364]
Code
$counter = '0';
foreach ($paper['book']['Paper'] as $otherPaper) {
if ((!empty($otherPaper['name'])) && ($counter < '7') && ($otherPaper['available'] == 1)) {
Cake\Error\ErrorTrap->handleError() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/templates/Papers/view.php, line 364
/var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/View/View.php /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/View/View.php, line 1188
Cake\View\View->_evaluate() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/View/View.php, line 1145
Cake\View\View->_render() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/View/View.php, line 785
Cake\View\View->render() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Controller/Controller.php, line 712
Cake\Controller\Controller->render() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Controller/Controller.php, line 516
Cake\Controller\Controller->invokeAction() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Controller/ControllerFactory.php, line 166
Cake\Controller\ControllerFactory->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Controller/ControllerFactory.php, line 141
Cake\Controller\ControllerFactory->invoke() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/BaseApplication.php, line 362
Cake\Http\BaseApplication->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 86
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Middleware/CsrfProtectionMiddleware.php, line 159
Cake\Http\Middleware\CsrfProtectionMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Middleware/BodyParserMiddleware.php, line 157
Cake\Http\Middleware\BodyParserMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Routing/Middleware/RoutingMiddleware.php, line 118
Cake\Routing\Middleware\RoutingMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Routing/Middleware/AssetMiddleware.php, line 69
Cake\Routing\Middleware\AssetMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Error/Middleware/ErrorHandlerMiddleware.php, line 115
Cake\Error\Middleware\ErrorHandlerMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/debug_kit/src/Middleware/DebugKitMiddleware.php, line 60
DebugKit\Middleware\DebugKitMiddleware->process() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 82
Cake\Http\Runner->handle() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Runner.php, line 60
Cake\Http\Runner->run() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/vendor/cakephp/cakephp/src/Http/Server.php, line 104
Cake\Http\Server->run() /var/www/dce7ae55-385b-4ffa-8595-3ec5e61ff110/public_html/app/webroot/index.php, line 37
[main]
