Meteorology applied to Urban Air Pollution Problems Lectures
course Meteorology applied to Urban Air Pollution Problems
Alexander Baklanov, Danish Meteorological Institute Young
Scientists School on Computational Information Technologies for
Environmental Sciences: CITES-2005 Novosibirsk, Russia, March
13-19, 2005 Slide 2 Meteorology applied to Urban Air Pollution
Problems: Lecture schedule . 17 2005 11:00 13:00 (/ ) 2.
Meteorology applied to Urban Air Pollution Problems. Alexander
Baklanov (Danish Meteorological Institute, Denmark) 13:00 14:30
14:30 15:30 - 3. Meteorology applied to Urban Air Pollution
Problems. Alexander Baklanov (Danish Meteorological Institute,
Denmark) 15:30 - ( , ) . 18 2005 9:00 13:15 (/ ) 1. Meteorology
applied to Urban Air Pollution Problems. Alexander Baklanov (Danish
Meteorological Institute, Denmark) 11:00 11:15 - 2. Meteorology
applied to Urban Air Pollution Problems. Alexander Baklanov (Danish
Meteorological Institute, Denmark) 13:15 14:30 Slide 3 Structure of
the Lectures I.Introduction to European research (COST Actions 710,
715, 728, 732, SATURN/EUROTRAC, CLEAR cluster, ACCENT, etc.)
II.Structure of the urban boundary layer III.Modification of flow
and turbulence structure over urban areas IV.The surface energy
balance in urban areas V.The mixing height and inversions in urban
areas VI.Evaluation and analysis of European peak pollution
episodes VII.European urban experiments (Copenhagen, ESCOMPTE,
BUBBLE, etc.) VIII.Preparation of meteorological input data for
urban air pollution models IX.Integrated modelling : Forecasting
Urban Meteorology, Air Pollution and Population EXposure (FUMAPEX)
and COST 728 X.Summary of achievements, gaps in knowledge,
recommendations for further research Slide 4 Why Urban Meteorology
Now? Technological Advances Remote sensing and other platforms
Computer models Homeland Security Atmospheric Transport and
Diffusion (ATD) models Health and Safety High impact weather Air
quality Slide 5 Why do we have to consider the urban effects? What
kind of effects? Slide 6 Local-scale inhomogeneties, sharp changes
of roughness and heat fluxes, Wind velocity reduce effect due to
buildings, Redistribution of eddies due to buildings, large =>
small, Trapping of radiation in street canyons, Effect of urban
soil structure, diffusivities heat and water vapour, Anthropogenic
heat fluxes, urban heat island, Internal urban boundary layers
(IBL), urban Mixing Height, Effects of pollutants (aerosols) on
urban meteorology and climate, Urban effects on clouds,
precipitation and thunderstorms. Urban BL features: Slide 7 At
small scale in the urban canopy, the built environment can induce
negative effects: A city can be considered as a protect area for
meso scale atmospheric events : Urban heat island has a positive
influence in the winter outdoor thermal comfort and the energy
consumption Urban roughness mitigates wind speed actions on tall
buildings above the mean roof level But over speed area around
buildings low diffusion of pollutants in street canyon Lack of
ventilation for indoor and outdoor comfort Slide 8 Buildings
located downwind of small roughness (sea and open country) had more
damages on structure Wind effects on structure urban suburbs Open
country sea % of damages Example: effects of storm Lothar (1999)
Slide 9 The Urban System (EU 5FP City of Tomorrow) Interactions
between the city, human environment and biophysical environment
INPUTS EnergyMoney Food Information WaterRaw Materials Manufactured
goods HUMANTHE CITYBIOPHYSICALENVIRONMENT PeoplePhysical
StructureAtmosphere & Energy Flows EthnicityBuilding
TypeHydrological Cycle PoliticsLayoutSoils, Vegetation, Fauna
TechnologyGeology & Landforms OUTPUTS WastesEmployment Liquids
Wealth SolidsManufactured Goods GasesDegraded Energy LINKS TOUrban
Systems OTHERRural Systems Regions Transport Communication From
Bridgman et al. (1996) Slide 10 Introduction to European research
COST Actions 710, 715, 728, 732, SATURN/EUROTRAC/TRAPOS, CLEAR
cluster, FUMAPEX project, ACCENT Network of Excellence,
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
WMO GURME project US EPA/NOAA projects Slide 11 Harmonisation in
the pre-processing of meteorological data for dispersion models
COST710 In the framework of COST, there has been an international
action, COST 710, aimed at Harmonisation in the pre-processing of
meteorological data for dispersion models. COST 710 has been
followed by a related action, COST 715, concerning Urban
Meteorology applied to Air Pollution Problems. A somewhat related
action, COST 732, will be carried out from 2005 onwards. COST 732
is entitled Quality Assurance and Improvement of Microscale
Meteorological Models. Meteorology applied to Urban Air Pollution
Problems - COST 715 In the framework of COST, an international
action has been conducted aimed at increasing knowledge of, and the
accessibility to, the main meteorological parameters which
determine urban pollution levels. The action was designated
initiated COST 715. COST 715 follows a previous action, COST 710.
COST - European Co-operation in the field of Scientific and
Technical Research
(http://cost.cordis.lu/src/domain_detail.cfm?domain=7) Domain:
Meteorology Slide 12 Working Group 1:Urban wind field Working Group
2: Energy Budget and the Mixing height in Urban Areas Working Group
3: Meteorology during peak pollution episodes Working Group 4:
Input Data for Urban Air Pollution Models Meteorology applied to
Urban Air Pollution Problems - COST 715 (1998 2004) Slide 13
Working Group 1: Urban wind field Goals Review and evaluate methods
to describe and parameterise the wind field over urban areas from
routine meteorological observations: near-surface conditions
(roughness sublayer) profile throughout the UBL possibly:
distinction between different locations within a city
recommendations on what /how Met. Services (and others) should
measure in urban areas Methods Review existing methods (theories)
for the specific goals above identify existing data sets for the
specific goals above identify new data sets develop general
semi-empirical relationships for the description of the UWF and
related parameters Plans In the longer term, seeking new directions
for developing a theory for the urban wind profile Evaluation of
the role of alternative tools such as numerical models or remote
sensing techniques Slide 14 Working Group 2: The Surface Energy
Budget and the Mixing height in Urban Areas Background Urban
pollution meteorology is characterised by a number of fundamental
parameters and their evolution in time, which all have specific
problems as to their monitoring, representativeness,
parameterisation and modelling. Within COST-715, WG2 addresses the
specific problems in describing the surface energy balance and the
mixing height. The surface energy balance and the surface
temperature and heat fluxes determine the hydrostatic stability
conditions in the lower atmosphere and regulate its strength for
mixing pollutants, the mixing height parameter determines the
available volume for pollutants mixing. The activities of WG2: To
review theoretical concepts of the structure of the urban boundary
layer. To review and assess pre-processors, schemes and models for
determining the mixing height, the surface energy budget and the
stability that are available to the participants. Cases of strong
stability and/or windless conditions are of special interest. To
review theoretical models together with available field
measurements and LES for calculation of the minimum friction
velocity and the heat transfer coefficient. Conditions of shear
free convection over high roughness are of main importance To
identify and review suitable data sets within and outside the group
that could be used to test and validate the pre- processors and
models. To carry out intercomparisons and to summarise comparisons
of different schemes against each other and against data under
specific conditions. To assess the influence of the model outputs
of certain specific effects such as complex topography, strong
heterogeneity, slope effects and canopy trapping on radiative
fluxes. To assess the suitability of remote sensing tools to
estimate canopy characteristics and surface fluxes. To provide
recommendations for the improvement of existing pre-processors and
models and for the development of new schemes. To provide
recommendations for planning and conducting field campaigns in
order to fill the important existing gaps for empirical data of key
parameters for urban air pollution. To promote co-ordination of
related activities in Europe of presently scattered works,
objectives, and responsibilities. Slide 15 Working Group 3:
Meteorology during peak pollution episodes During air pollution
episodes pollutant concentrations are highest, and the related
adverse health impact on the public should therefore be reliably
evaluated. The meteorological conditions prevailing in the course
of episodes are at the same time commonly the most difficult to
model with the computing tools presently available. European Union
nevertheless requires practical measures to be taken, if air
quality limit values are exceeded. Slide 16 Coordinator: Prof.
Ranjeet S Sokhi Atmospheric Science Research Group (ASRG)
University of Hertfordshire, UK Scientific Officer: Viorel
Vulturescu European Commission, DG Research Launched: December 2002
CLEAR Cluster of European Air Quality Research
http://www.nilu.no/clear Slide 17 Aim of CLEAR Threefold aim: To
improve our scientific understanding of atmospheric processes,
composition and pollution variabilities on local to regional scales
To provide next generation tools for end users and stakeholders for
managing air pollution and responding to its impact To help create
a critical mass of expertise and ambition to address future
research needs in the areas of air pollution, its impact and
response strategies. Slide 18 Eleven Participating Projects FP5,
EESD, City of Tomorrow ATREUS (Coordinator: Dr Agis Papadopoulos,
University of Thessaloniki) Human Potential Research network -
Advanced Tools for Rational Energy Use towards Sustainability with
emphasis on microclimatic issues in urban applications OSCAR
(Coordinator: Professor Ranjeet S Sokhi, University of
Hertfordshire) -Optimised Expert System for Conducting
Environmental Assessment of Urban Road Traffic FUMAPEX
(Coordinator: Dr Alexander Baklanov, DMI) Integrated Systems for
Forecasting Urban Meteorology, Air Pollution and Population
Exposure ISHTAR (Prof Emanuele Negrenti, ENEA) - Integrated
Software for Health, Transport efficiency and Artistic heritage
Recovery Slide 19 Eleven Participating Projects FP5, EESD, City of
Tomorrow SAPPHIRE (Coordinator: Dr Stuart Harrad, University of
Birmingham) - Source Apportionment of Airborne Particulate Matter
and Polycyclic Aromatic Hydrocarbons in Urban Regions of Europe
URBAN AEROSOL (Professor Mihalis Lazaridis, Technical University of
Crete) Characterisation of Urban Air Quality Indoor/Outdoor
Particulate Matter Chemical Characteristics and Source-to-Inhaled
Dose Relationships URBAN EXPOSURE (Dr Trond Bohler, NILU)
Integrated Exposure Management Tool Characterising Air Pollution
Relevant Human Exposure in Urban Environment Slide 20 Eleven
Participating Projects FP5, EESD, City of Tomorrow BOND
(Coordinator: Professor John Bartzis, NCSRD) Biogenic Aerosols and
Air Quality in the Mediterranean Area MERLIN (Coordinator:
Professor Rainer Friedrich, University of Stuttgart)
Multi-pollutant, Multi-Effect Assessment of European Air Pollution
Control Strategies: an Integrated Approach AIR4EU (Coordinator:
Professor Peter Biltjes, TNO) FP6 Project -Air Quality Assessment
for Europe: Local to Continental Scales INTEGAIRE (Coordinator: Dr
Eva Banos, EUROCITIES) - Integrated Urban Governance and Air
Quality Management in Europe Slide 21 CLEAR 20 Partner Countries
Slide 22 FUMAPEX: Integrated Systems for Forecasting Urban
Meteorology, Air Pollution and Population Exposure FUMAPEX:
Integrated Systems for Forecasting Urban Meteorology, Air Pollution
and Population Exposure Project objectives: (i)the improvement of
meteorological forecasts for urban areas, (ii)the connection of NWP
models to urban air quality (UAQ) and population exposure (PE)
models, (iii)the building of improved Urban Air Quality Information
and Forecasting Systems (UAQIFS), and (iv)their application in
cities in various European climates. Slide 23 UAQIFS: Scheme of the
suggested improvements of meteorological forecasts (NWP) in urban
areas, interfaces to and integration with UAP and PE models Slide
24 FUMAPEX target cities for improved UAQIFS implementation #1
Oslo, Norway #2 Turin, Italy #3 Helsinki, Finland #4
Valencia/Castellon, Spain #5 Bologna, Italy #6 Copenhagen, Denmark
Different ways of the UAQIFS implementation: (i)urban air quality
forecasting mode, (ii) urban management and planning mode, (iii)
public health assessment and exposure prediction mode, (iv) urban
emergency preparedness system. Slide 25 FUMAPEX: Forecast procedure
in Oslo Met.no Slide 26 COST 728: Enhancing meso-scale
meteorological modelling capabilities for air pollution and
dispersion applications (2004-2009) The Action will encourage the
advance of the science in terms of parametrisation schemes,
integration methodologies/strategies, air pollution and other
dispersion applications as well as developing model evaluation
methods. In terms of air pollution applications it is recognised
that chemical mechanisms and emissions pre-processing are vital
components. Four working groups (WG): WG1Meteorological
parameterisation/applications WG2 Integrated systems of MetM and
CTM: strategy, interfaces and module unification WG3 Mesoscale
models for air pollution and dispersion applications WG4Development
of evaluation tools and methodologies Slide 27 The overall aim of
WG2 will be to identify the requirements for the unification of
MetM and CTM/ADM modules and to propose recommendations for a
European strategy for integrated mesoscale modelling capability.
WG2 activities will include: Forecasting models Assessment models
WG2: Integrated systems of MetM and CTM/ADM: strategy, interfaces
and module unification Slide 28 Meteorology and Air Pollution: as a
joint problem Meteorology is a main source of uncertainty in APMs
=> needs for NWP model improvements Complex & combined
effects of meteo- and pollution components (e.g., Paris, Summer
2003) Effects of pollutants/aerosols on meteo&climate
(precipitation, thunderstorms, etc) Three main stones for
Atmospheric Environment modelling: 1.Meteorology / ABL,
2.Chemistry, => Integrated Approach 3.Aerosol/pollutant dynamics
(chemical weather forecasting) 4.Effects and Feedbacks Slide 29 Why
we need to build the European integration strategy? European
mesoscale MetM/NWP communities: ECMWF HIRLAM COSMO ALADIN/AROME UM
--------- WRF MM5 RAMS European CTM/ADMs: a big number problem
oriented not harmonised (??) .. NWP models are not primarily
developed for CTM/ADMs and there is no tradition for strong
co-operation between the groups for meso/local-scale the
conventional concepts of meso- and urban-scale AQ forecasting need
revision along the lines of integration of MetM and CTM US example
(The models 3, WRF-Chem) A number of European models A universal
modelling system (like ECMWF in EU or WRF-Chem in US) ??? an open
integrated system with fixed architecture (module interface
structure) Slide 30 ACCENT's goals are to promote a common European
strategy for research on atmospheric composition change, to develop
and maintain durable means of communication and collaboration
within the European scientific community, to facilitate this
research and to optimise two-way interaction with policy-makers and
the general public. Changes in atmospheric composition directly
affect many aspects of life, determining climate, air quality and
atmospheric inputs to ecosystems. In turn, these changes affect the
fundamental necessities for human existence: human health, food
production, ecosystem health and water. Atmospheric composition
change research is therefore fundamental for the future orientation
of Europe's Sustainable Development strategy. Slide 31 Slide 32
Part II: Structure of the urban boundary layer Vertical structure
Horizontal non- homogeneity Temporal variability Slide 33 The
atmospheric boundary layer Lowest layer of the atmosphere
Interactions with the earths surface are important Diurnal
evolution is complicated Turbulence generation by shear and
buoyancy is important Fluxes of energy, momentum, and moisture
to/from the surface Slide 34 Problems in defining the boundary
layer Complicated vertical structure Sub-layers grow and decay over
the diurnal cycle Turbulence is often intermittent, complicating
the classification of stability Boundary layer top is not
necessarily at inversion Slide 35 The structure of the urban
boundary layer - meteorological view after T. Oke (1988) Slide 36
Slide 37 Scales in an Urban Environment Slide 38 Diurnal evolution
of the PBL Slide 39 Diurnal evolution of urban BL day night Slide
40 Boundary layer characteristics Daytime: Deep mixed layer from
surface heating Turbulent eddies on the scale of BL depth Thermally
driven flows can develop from spatial variations in surface heating
Nighttime: Surface inversion develops from radiational cooling
Mixed layer can persist above inversion Turbulence can be
intermittent and mix down faster and warmer air Slide 41 Part III:
Ways to resolve the UBL structure 1. Obstacles-resolved numerical
models - CFD => turbulent closure, bc, geometry, etc. - LES, ,
DNS - simple box models 2. Parameterization of sub-grid processes -
theoretical - experimental - numerical 3. Downscaling of models /
Nesting techniques - NWP-local-scale meteorological models -
Mesoscale models CFD tools - Mesoscale models Parameterized models
Slide 42 Key parameters for urban models of different scales
(COST715) Slide 43 One example of the first way (CFD) Scheme of the
building complex and 6 m height horizontal wind field (after
Mastryukov et al.) Slide 44 High-resolution mapping of urban areas
CORINE and PELCOM data up to 250 m resolution Land-use database
with the resolution 25 x 25 meters (DMU) GIS databases of urban
structure (BlomInfo A/S) Slide 45 Slide 46 Momentum equations for
urban canopy model Slide 47 1.Modifying the existing non-urban
(e.g. MOST) approaches for urban areas by finding proper values for
the effective roughness lengths, displacement height, and heat
fluxes (adding the anthropogenic heat flux, heat storage capacity
and albedo change). In this case, the lowest model level is close
to the top of the urban canopy (displacement height), and a new
analytical model is suggested for the Urban Roughness Sublayer
which is a critical region where pollutants are emitted and where
people live. 2.Alternatively, source and sink terms are added in
the momentum, energy and turbulent kinetic energy equation to take
into account the buildings. Different parameterizations (Masson,
2000; Kusaka et al., 2001; Martilli et al., 2002) had been
developed to estimate the radiation balance (shading and trapping
effect of the buildings), the heat, the momentum and the turbulent
fluxes inside the urban canopy, taking into account a simple
geometry of buildings and streets (3 surface types: roof, wall and
road). Two approaches to parameterise the urban canopy effect:
Slide 48 Slide 49 Wind tunnel data for urban canopy Slide 50
Review: theories relating to urban wind profiles (WG1 COS715)
Theories will be required for various aspects of the UWF: Roughness
sublayer (RS): profile of Reynolds stress & local scaling
within RS wind profile no theory, but good results;
parameterisation exists for Reynolds stress profile (to be extended
to more data sets) Required: friction velocity of inertial sublayer
(IS), ; z * and d Stability effects? (profile of sensible heat
flux? WG2) Urban canopy (part of RS) Little variation within canopy
[height and position] Sharp transition from canopy to above roof
region Similar to plant canopies: Theory? (Raupach et al., 1996)
Possible approach: match the canopy and the RS profiles for 0
