Developments in ADMS-Urban and ADMS-Roads …gamta.lt/files/2_ADMS_programines_irangos_naujienos_D_Carruthers.pdf · ADMS-Roads including new road traffic emission factors . ADMS-Urban

David Carruthers

User Group Meeting

Vilnius

March 2013

Developments in ADMS-Urban and

ADMS-Roads including new road

traffic emission factors

ADMS-Urban and ADMS-Roads User Group Meeting 2012

Contents

• New emissions in ADMS-Urban and ADMS-Roads 3.1

– Background

– How do the new emission factors compare to the old?

– New EFT v5.1 in ADMS-Urban and ADMS-Roads

– Modelling NO2 using the EFT factors

• Upcoming model developments

– Urban flows and canyons

– Nesting ADMS-Urban in regional models

– Taking account of time history of emissions within ‘plume’

• Other model enhancements

– Mapper

– Links to Google Earth

– Model speed-up


New emissions in ADMS-Urban and ADMS-Roads 3.1

Background

• UK ‘Emission Factor Toolkit’ factors included in ADMS-Urban

and ADMS-Roads

• Current update to EFT includes:

– NOx emission factors:

• COPERT IV European speed emission curves (year

independent)

• Mileage degradation factors (year dependent)

– PM emission factors:

• Includes exhaust, brake wear, tyre wear and road abrasion

• Still no inclusion of resuspension factors

• New fleet data, with factors for:

– London, England, Scotland, Wales and Northern Ireland

– How applicable are these to the Baltic states?



How do the new emission factors compare to the old?

• Tables taken from the ‘LAQM Support Helpdesk Advice Note

EFT’ http://laqm.defra.gov.uk/review-and-assessment/tools/emissions.html#eft

Urban driving:

• All factors higher

• Diesel LDVs much higher

Motorway driving:

• Diesel LDVs much higher

• Decreases for HDVs

Year


Motorcycles

Cars

LGVs

Buses/coaches

HGVs

20

40

60

2010 2015 2020

Petrol carDiesel car


How do the new emission factors compare to the old?

• Consider emissions for a road with a typical fleet mix, for 2010,

2015, 2020

Typical fleet mix

% c

hange

Increase in NOx &

PM10 estimates

% incre

ase



New EFT v5.1 in ADMS-Urban and ADMS-Roads

• 4 new emission factor datasets

New datasets: EFT v5.1 (#Vehicle Categories)

EFT v5.1 (2 VC) EFT v5.1 (6 VC) EFT v5.1 (7 VC) EFT v5.1 (8 VC)

Light duty vehicle

Heavy duty vehicle

Car

Diesel car

Petrol car

LGV

Taxi

Motorcycle

HGV

Rigid HGV

Articulated HGV

Bus and coach



New EFT v5.1 in ADMS-Urban and ADMS-Roads

• Each dataset is categorised by region

• Other changes

New region types

London England Scotland Wales Northern

Ireland

London (central)

London (inner)

London (outer)

Urban

Rural

Motorway

New dataset (EFT v5.1) Old dataset (EFT v4.2)

Year ranges 2008 - 2030 2006 - 2025

Speed range (km/hr) 5 - 140 5 - 120



Modelling NO2 using the EFT factors

• New primary NO2 estimates have been published alongside

the new emission factors (NAEI Data Warehouse – download

spreadsheet and Advice note).

Perc

enta

ge

of

NO

x

tha

t is

N

O2

Primary NO2 – by vehicle type (2015)







Perc

enta

ge

of

NO

x

tha

t is

N

O2

Primary NO2 – for all traffic

Year







• Section 3.2.1 in the User Guide (p32) gives the steps required

to include primary NO2 emissions in your model run (via

Emissions Inventory database).


Upcoming model developments



Urban Flows and Canyons

• Improve the modelling of the important physical processes in

urban (and also industrial) environments



Urban Flows and Canyons M

od

elle

d N

Ox c

on

ce

ntr

atio

n (

µg

/m3)

Measured NOx concentration (µg/m3)

BRUTAL ADMS-Urban

Queue

ADMS-Urban

PCM CMAQ-urban ERG toolkit

Kerbside

Roadside

Suburban

Urban

Background

500

500 500

500

London Model Inter-comparison Study: Annual Average NOx


NO2 ‘pollution roses’ for Marylebone Road 2008:

• Bivariate polar plot of NO2 concentration at Marylebone Road:

– Wind speed on radial axis

– Concentration shown by colour

• Road width 22m, canyon height 20m

• Shows that models predict high concentrations for low wind speeds in all

directions

• Effect of street canyon shown in measured data plot

ADMS

calculated Monitored




• OSPM approach

Prevailing wind Uo

Building

height HB

Canyon width L

Wind side Lee side

Building

height HB

Recirculation

region




OSPM approach • Well mixed recirculating

region

• No channelling of flow along

canyon

• Flow/turbulence within canyon

has little dependence on

HB and L

• Not possible to consider pavements

or road lanes

• Not formulated for one-sided or

asymmetric canyons

Recirculation

zone

Wind

side

Lee

side

Uo




b

ΔUw

θ

g

Uo

Upcoming model developments: Urban Flows and Canyons

Flow through widely separated buildings


mean streamline

wakes attach

street 2 street 1

Domain Dm

b

g

ΔV1

θ

Uo


Flows with wake attached to downstream building


mean vertical profile

of wind speed

U component in

x direction

Uo

Vm

Um

ΔUm

Uo

Um + ΔUm

z


Flow through closely packed aligned buildings


Uo

Velocity profile Turbulence profile

b

g

UH

UC

z/H

z/H


Velocity profiles in and above urban canopy


New canyon/urban street model

• Well mixed recirculating region

• Flow/turbulence within canyon has

dependence on height and width;

allows for high aspect ratio

• Can consider pavements and road

lanes

• One-sided/asymmetric canyons

• Channelling of flow along canyon

source

mth

street

m+1th

street

plume

centrelines

g




• Dispersion – definition of sources Different sources with weighting depending on porosity, h, g and angle of wind to road.

road in canyon

parallel perpendicular

recirculation ground level source

source at canyon top

volume source at end of canyon

buildings

buildings

pavement

q1 - ground level line source in street with flow parallel to street

q2 - ground level line source along street with flow perpendicular to street

q3 - constant concentration in canyon (recirculating flow)

q4 - ground level line source along street with flow parallel to upstream wind

q5 – elevated line source parallel to street at height of buildings with flow parallel to

upstream wind.

q6 - volume source at end of street with flow parallel to upstream wind




Nesting local model (ADMS-Urban) within

regional model: motivation

• Why nest a local model within a regional model?

• What are the advantages of a nested model?

Model feature Model

Regional (eg grid based) Local (eg Gaussian plume)

Domain extent Country (few 1000 km) City (50km)

Meteorology Spatially and temporally

varying from meso scale

models

Usually spatially

homogeneous

Dispersion in low wind

speed conditions

Models stagnated flows

correctly

Limited modelling of

stagnated flows

Deposition and

chemical processes

Reactions over large spatial

and temporal scales

Simplified reactions over

short-time scales

Source resolution Low High

Validity Background receptors Background, roadside and

kerbside receptors


O3

NO2 VOC

NO

13 Sep 99 Level one 3:00pm

O3

NO2

NO

VOC

HKUST CMAQ/CAMx Modelling for Hong Kong;

ADMS-Urban to be nested within this


Nesting - Example of Preliminary Model results:

NO2 average contours (CMAQ)

CMAQ outer

domain

ADMS-Urban

nested domain

9km

Consistency of

background

concentrations

1km

NO2 µg/m³


source

wind

speed, U

U x 1 hour

U x 2 hours

Concentration due to

emissions in current hour

Concentration due to

emissions in previous hour


Emission history 1


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1 3 5 7 9 11 13 15 17 19 21 23E

mis

sio

n F

ac

tor

Hour

Weekday

Saturday

Sunday

source

wind

speed, U

U x 1 hour

U x 2 hours

• Central London road

NOx emission factors

• Rapid increase in

emissions at rush

hour


Emission history 2


Other model developments

- Impacts of cuttings, embankments, tunnels and flyovers


• Improvement to initial mixing height estimate

– Currently 1m for all vehicles and at all speeds

– May have a significant effect on ground level concentrations

– Equal to source height at low speeds

– Related to vehicle height at high speeds due to traffic induced

turbulence

Other model developments

- Improvement to initial mixing height estimate

Slow traffic

speeds

Fast traffic

speeds


Other model enhancements


• Link to ADMS Mapper

• Currently implemented in ADMS 4/5

– View sources, buildings, specified output points and the output grid

– Add, move, edit and delete sources and specified points

– Define the output grid

– Display concentration contours (plots created independently or

using Surfer or Spatial Analyst)

– Other GIS functionality (for example view background maps, use

measuring tool, modify layer features, display feature names,

export in different formats)

Visualisation I


• ADMS Mapper

Visualisation II


• ADMS Mapper

Visualisation III


Visualisation IV

• Mapper link to Google Earth

• Google Earth visualisation


• General speed up in next release due to code improvements;

significant speed up for complex terrain module calculations

• Take advantage of multiprocessor machines:

– Split up model runs: different meteorology, and/or different model

domains

– Managed by Run Manager

Speed up code


Summary

• New emissions in ADMS-Urban and ADMS-Roads 3.1

– Background

– How do the new emission factors compare to the old?

– New EFT v5.1 in ADMS-Urban and ADMS-Roads

– Modelling NO2 using the EFT factors

• Upcoming model developments

– Urban flows and canyons

– Nesting ADMS-Urban in regional models

– Taking account of time history of emissions within ‘plume’

• Other model enhancements

– Mapper

– Links to Google Earth

– Model speed-up

Documents

Developments in ADMS-Urban and ADMS-Roads …gamta.lt/files/2_ADMS_programines_irangos_naujienos_D_Carruthers.pdf · ADMS-Roads including new road traffic emission factors . ADMS-Urban