Urban Boundary Layer interactions with weather, air quality, and climate change processes

1
Urban Boundary Layer interactions with weather,
air quality, and climate change processes

• Prof. Robert Bornstein
• Dept. of Meteorology
• San Jose State University
• San Jose, CA USA
• pblmodel_at_hotmail.com
• Presented at the
• HUJI
• 1 Jan 2009

2
OVERVIEW

• URBAN CLIMATE
• WHY STUDY IT
• ITS CAUSES
• ITS IMPACTS
• CALIFORNIA COASTAL COOLING
• DATA
• ANALYSIS
• URBAN PBL MODELS
• FORMULATION
• APPLICATIONS (LA, HOUSTON, ATLANTA, ISRAEL)
• FUTURE EFFORTS

3
URBAN WEATHER ELEMENTSbattles between
conflicting effects

• VISIBILTITY decreased
• TURBULENCE increased (mechanical thermal)
• PBL NIGHT STABILITY neutral
• FRONTS (synoptic sea breeze) slowed
• TEMP PRECIP increased (UHI) or decreased
• PRECIP increased (UHI) or decreased
• WIND SPEED (V) increased or decreased
• WIND DIRECTION con- or divergence
• THUNDERSTORMS triggered or split

4
HUMAN-HEALTH IMPACTS OF URBAN CLIMATE

• gt UHI ? THERMAL STRESS
• gt PRECIP ENHANCEMENT ? FLOODS
• gt URBAN INDUCED INVERSIONS ?
• POLLUTED LAYERS
• gt TRANSPORT DIFF PATTERNS FOR
• POLLUTION EPISODES
• EMERGENCY RESPONSE (i.e., TOXIC RELEASES)

5
NEW URBAN CLIMATE CAUSES

• GRASS SOIL ?
• CONCRETE BUILDINGS ?
• ALTERED SURFACE HEAT FLUXES
• FOSSIL FUEL CONSUMPTION ?
• ATMOSPHERIC POLLUTION AND HEAT
• ATM POLLUTION?
• ALTERED SOLAR IR ENERGY

6
St. Louis nocturnal PBL warm near-neutral,
polluted, urban-plume vs. rural stable
surface-inversion
0F
urban-plume
inversion
Clark McElroy (1970)
7
Urban effects on wind speed

• FAST LARGE-SCALE (i.e., SYNOPTIC) SPEED ?
• SMALL UHI ?
• URBAN SFC ROUGHNESS (Z0) INDUCED DECELERATION
• SLOW SYNOPTIC SPEEDS
• LARGE UHI ?
• INWARD-DIRECTED ACCELERATION
• CRITICAL SPEED 3-4 m/s (FOR NYC London)

8
NYC DAYTIME ?V (z)
urban
rural
9
URBAN EFFECTS ON WIND DIR

• FAST SYNOPTIC SPEED ?WEAK UHI ?
• URBAN BUILDING-BARRIER EFFECT ?
• FLOW DIVERGES AROUND CITY
• SLOW SYNOPTIC SPEED ? LARGE UHI ? LOW-p ?
  CONVERGENCE INTO CITY
• MODERATE SYNOPTIC SPEED ? CONVERGENCE-ZONE
  ADVECTED TO DOWNWIND URBAN-EDGE

10
NOCTURNAL UHI-INDUCED SFC-CONFLUENCE WITH gt
otherwise-calm UHI confluence-center over urban
center gt low-speed regional-flow from N UHI
confluence-center advected to downwind urban-edge
Frankfurt Case
NYC Case
Manhattan
11

• NYC daytime non-UHI Sfc div-field
• like flow around rock
• div-area over city-core ? w lt 0
• conv-areas on lateral urban-edges ? w gt 0

D ?u/?x ?v/?y
No obs
12
NYC TETROON-DERIVED w-VELOCITIES Note (a) larger
w-speeds during unstable daytime hours (b)
Smaller w-speeds during more stable nighttime
hours (c) Thin weak nocturnal urban
elev-inversion layer-base stops w
?
?
13

• Weak cold-frontal (N to S) passage over NYC
• Hourly positions (left)
• At 0800 EST (right) T, q, SO2
  z-profile-changes
• showed lowest 250 m of atm not-replaced, as
  front
• jumped over city

See ?
14
URBAN IMPACTS ON PRECIP

• INITATION BY THERMODYNAMICS (at SJSU)
• LIFTING FROM
• UHI CONVERGENCE
• THERMAL MECHANICAL CONVECTION
• DIVERGENCE FROM BUILDING BARRIER EFFECT
• AEROSOL MICROPHYSICS (at HUJI)
• SLOWER SECONDARY DOWNWIND ROLE
• METROMEX PROF. ROSENFELD

15
NYC two-summer daytime-average thunderstorm-precip
radar-echoes (ss from uniform-distribution) for
cases all, convective, moving
Formed over city
splitting case
Split by city
16
Dispersion effects

• Vertical diffusion limited by urban-induced
• elevated inversions (next slide)
• Transport 3-D effects of urban-induced
  flow- modifications
• Convergence-zones effects due to
• Urban effects
• Sea breezes

17
Urban-induced nocturnal elevate inversion-I traps
area-source emissions, while power plant plume is
trapped b/t urban-induced inversions I II
inversion III is regional inversion
Plume
Area Sources
18
California Coastal-Cooling (to appear J. of
Climate, 2009)

• Global CA observations generally show
• asymmetric warming (more warming for Tmin than
  for Tmax) (next graph)
• acceleration since mid-1970s
• CA downscaled global-modeling (next map)
• done (at SCU elsewhere) onto 10 km grids
• shows summer warming that decreases towards the
  coast (but does not show coastal cooling)

19
Not much change from mid- 40s to mid-70s, when
values started to again rapidly rise
20
Statistically down-scaled (Prof. Maurer, SCU)
1950-2000 annual summer (JJA) IPCC temp-changes
(0C) show warming rates that decrease towards
coast red dots are COOP sites used in present
study boxes are study sub-areas
21
Earlier climate-change (for CA) studies have
dis-cussed climate-change impacts in terms of
increased

• SSTs urbanization (Goodridge 91, Karl et al.
  93 )
• Cloud cover (Nemani et al. 2001)
• Coastal upwelling (Bakum 1990 Snyder et al.
  2003 McGregor et al. 2007)
• Land-cover conversions (Chase et al. 2000 Mintz
  1984 Zhang 1997)
• Irrigation (Christy et al. 06 Kueppers et al.
  07, Bonfils Duffy 07, Lobell Bonfils et
  al. 08)
• Solar absorption (Stenchikov Robock 1995)

22
The current Hypothesis

• INCREASED GHG-INDUCED INLAND TEMPS?
• INCREASED (COAST TO INLAND) PRESSURE TEMP
  GRADIENTS?
• INCREASED SEA BREEZE FREQ, INTENSITY,
  PENETRATION, /OR DURATION ?
• COASTAL AREAS SHOULD SHOW COOLING SUMMER DAYTIME
  MAX TEMPS (i.e., A REVERSE REACTION)
• NOTE
• NOT A TOTALLY ORIGINAL IDEA
  ?

23
CURRENT DATA

• NCDC DAILY MAX MIN 2-METER TEMPS
• FROM ABOUT 300 CA NWS COOP SITES
• FOR 1948-2005
• HAVE BEEN USED IN MANY OTHER CA CLIMATE-CHANGE
  STUDIES
• ERA40 1.4 DEG REANALYSIS 1000-LST SUMMER
• SEA-LEVEL PRESSURES
• FOR 1970-2005

24
Results 1 SoCAB 1970-2005 summer (JJA) Tmax
warming/ cooling trends (0C/decade) solid,
crossed, open circles show stat p-values lt
0.01, 0.05, not significant, respectively
?
?
?
25
Results 2 SFBA CV 1970-2005 JJA Tmax
warming/cooling trends (0C/decade), as in
previous figure
?
?
?
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Significance of These all-CA Trends

• HIGHER TRENDS FROM 1970-2005 ?
• FOCUS NEEDED ON THIS PERIOD
• TMIN HAS FASTER RISE ?
• ASSYMETRIC WARMING IN LITERATURE
• BUT TMAX HAS SLOWER RISE, BECAUSE IT IS A SMALL
  DIFFERENCE B/T BIG POS-VALUE BIG NEG-VALUE (AS
  SEEN IN ABOVE SPATIAL PLOTS)
• TAVE DTR ARE ALSO THUS CONTAMINATED
• NEXT 2 SLIDES THUS SHOW SEPARATE TRENDS FOR CA
  COASTAL AND INLAND AREAS

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Note IPCC 2001 does show cooling over Central
California!!

31
Significance of above Coastal-Cooling and
Inland-Warming Trends

• CA ASSYMETRIC WARMING IN LITERATURE IS HEREIN
  SHOWN TO BE DUE TO COOLING TMAX IN COASTAL AREAS
  CONCURRENT WARMING TMAX IN INLAND AREAS
• PREVIOUS CA STUDIES
• THAT DID NOT LOOK SPECIFICALLY AT SUMMER DAYTIME
  COASTAL VS. INLAND VALUES HAVE THUS REPORTED
  CONTAMINATED TMAX, TAVE, DTR VALUES
• THEY, HOWEVER, ARE NOT INCONSISTENT WITH CURRENT
  RESULTS, THEY ARE JUST NOT AS DETAILED IN THEIR
  ANALYSES RESULTS

32
Trend in 1979-2002 ERA40 reanalysis of 1800 UTC
(1000 LT) JJA sea-level p-changes (hPa/decade)

• lets look at p, as it causes sea breezes
• dots 1.4-deg grids
• end-pts of solid lines pts for p-grad trend
  calcu-lation (next slide)
• H L strength-ened moved to NW (cant see in
  this slide)

33
Result 6 Trends in sea minus land JJA 1000 LT
sea-level p- gradient (hPa/100-km/decade) from
values at ends of lines in prev. Fig.

• Key
• SFBA (red)
• SoCAB (blue)

These stronger HPGFs ? stronger sea breezes ?
coastal cooling
34
Result 7. JJA 1970-2005 2 m Tmax trends for 4
pairs of urban (red, solid) rural (blue,
dashed) sites

• Notes
• All sites are near the cooling-warming border
• UHI-TREND absolute sum b/t warming-urban
  cooling-rural trends (K/decade)
• 3. SFBA sites
• Stockton (0.55)
• Sac. (0.51)
• 4. SoCAB sites
• (c) Pasadena (0.26)
• (d) S. Ana (0.12)

35
Notes on JJA daytime UHI-trend results

• The fastest growing cities had the fastest
  growing UHIs
• As no coastal sites showed warming T-max values,
  the calculation could only be done at these four
  pairs, located at the inland boundary b/t the
  warming and cooling areas
• The coastal sites would have cooled even more w/o
  their (assumed) growing UHIs

36
BENEFICIAL IMPLICATIONS OF COASTAL COOLING

• NAPA WINE AREAS MAY NOT GO EXTINCT (REALLY GOOD
  NEWS!) (next map)
• ENERGY FOR COOLING MAY NOT INCREASE AS RAPIDLY AS
  POPULATION (next graph)
• LOWER HUMAN HEAT-STRESS RATES
• OZONE CONCENTRATIONS MIGHT CONTINUE TO DECREASE,
  AS LOWER MAX-TEMPS MEAN REDUCED
• ANTHROPOGENIC EMISSIONS
• BIOGENIC EMISSIONS
• PHOTOLYSIS RATES

37
NAPA WINE AREAS MAY NOT GO EXTINCT DUE TO ALLEGED
RISING TMAX VALUES, AS PREDICTED IN NAS STUDY
38
Result 6 Peak-Summer Per-capita
Electricity-Trends

• Down-trend at cooling
• Coastal LA (blue) Pasadena
• (pink, 8.5/decade)
• gt Up-trend at warming
• inland Riverside (green)

• Up-trend at warming Sac Santa Clara
• Need
• detailed energy-use data for more sites
• to consider changed energy efficiency

39
Future Coastal-Cooling Efforts (PART 1 OF 2)

• EXPAND (TO ALL OF CA ISRAEL?)
• ANALYSIS OF OBS (IN-SITU GIS)
• URBANIZED MESO-MET (MM5, RAMS, WRF) MODELING
• SEPARATE INFLUENCES OF CHANGING
• LAND-USE PATTERNS RE
• AGRICULTURAL IRRIGATION
• URBANIZATION UHI-MAGNITUDE
• SEA BREEZE
• INTENSITY, FREQ, DURATION, /OR PENETRATION
• DETERMINE POSSIBLE SATURATION OF SEA- BREEZE
  EFFECTS FROM
• FLOW-VELOCITY COLD-AIR TRANSPORT
• AND/OR STRATUS-CLOUD EFFECTS ON LONG-
  SHORT-WAVE RADIATION

40
POSSIBLE FUTURE EFFORTS (PART 2 OF 2)

• DETERMINE CUMULATIVE FREQ DISTRIBU-TIONS OF
  MAX-TEMP VALUES, AS
• EVEN IF AVERAGE MAX-VALUES DECREASE,
• EXTREME MAX-VALUES MAY STILL INCREASE (IN
  INTENSITY AND/OR FREQUENCY)
• DETERMINE CHANGES IN LARGE-SCALE ATMOSPHERIC
  FLOWS
• HOW DOES GLOBAL CLIMATE-CHANGE EFFECT POSIT-ION
  STRENGTH OF PACIFIC HIGH THERMAL LOW?
• THIS IS ULTIMATE CAUSE OF CLIMATE-CHANGE

41
OUR GROUPS MESO-MODELING EXPERIENCE

• SJSU (MM5 uMM5)
• Lozej (1999) MS SFBA winter wave cyclone
• Craig (2002) MS Atlanta UHI-initiated
  thunderstorm (NASA)
• Lebassi (2005) MS Monterey sea breeze (LBNL)
• Ghidey (2005) MS SFBA/CV CCOS episode (LBNL)
• Boucouvula (2006a,b) Ph.D. SCOS96 episode (CARB)
• Balmori (2006) MS Tx2000 Houston UHI (TECQ)
• Weinroth (2009) PostDoc NYC-ER UDS urban-barrier
  effects (DHS)
• SCU (uRAMS)
• Lebassi (2005) Sacramento UHI (SCU)
• Lebassi (2009) Ph.D. SFBA SoCAB
  coastal-cooling (SCU)
• Comarazamy (2009) Ph.D. San Juan climate-change
  UHI (NASA)
• Altostratus (uMM5 CAMx)
• SoCAB (1996, 2008) UHI ozone (CEC)
• Houston (2008) UHI ozone (TECQ)
• Central CA (2008) UHI ozone (CEC)
• Portland (current) UHI ozone (NSF)
• Sacramento (current) UHI ozone (SMAQMD)

42
SJSU IDEAS ON GOOD MESO-MET MODELING

• MUST CORRECTLY REPRODUCE
• UPPER-LEVEL Synoptic/GC FORCING FIRST
• pressure (the GC/Synoptic driver) ?
• Synoptic/GC winds
• TOPOGRAPHY NEXT
• min horiz grid-spacing ?
• flow-channeling
• MESO SFC-CONDITIONS LAST
• temp (the meso-driver) roughness ?
• meso-winds

43
Case 1 MM5 SoCAB SCOS96 O3 episode (Boucouvula,
2 papers in Atmos. Environment)

• RUN 1 has
• No GC warming trend
• Wrong max and min T

RUN 5 corrected, as it used gt Analysis nudging
(to cap-ture GC trends in max-T) gt Reduced
deep-soil T (to capture correct min-T)
3-Aug
4-Aug
5-Aug
6-Aug
44
Case 2 ATLANTA UHI-INITIATED STORM OBS SAT
PRECIP (UPPER) MM5 ws precip (LOWER)
45
Recent Meso-met Model Urbanizations

• Need to urbanize momentum, thermo , TKE
• surface SfcBL diagnostic-Eqs.
• PBL prognostic-Eqs. (not done in NCAR uWRF)
• Start veg-canopy model (Yamada 1982)
• Veg-param replaced with GIS/RS urban-param/data
• Brown and Williams (1998)
• Masson (2000)
• Martilli et al. (2001) in TVM/URBMET
• Dupont, Ching, et al. (2003) in EPA/MM5
• Taha et al. (05, 08a,b,c) Balmori et al.
  (06) his uMM5 uses improved urban dynamics,
  physics, parameterizations, inputs

46
Within Gayno-Seaman PBL/TKE scheme
From EPA uMM5 Mason Martilli (by Dupont)
47
_________
______
3 new terms in each prog. equation
? Advanced urbanization scheme from Masson (2000)
48
But, uMM5 needs extra GIS/RS inputs as f (x, y,
z, t)

• land use (38 categories)
• roughness elements
• anthropogenic heat as f (t)
• vegetation and building heights
• paved-surface fractions
• drag-force coefficients for buildings
  vegetation
• building H to W, wall-plan, impervious-area
  ratios
• building frontal, plan, rooftop area densities
  
• wall and roof e, c?, a, etc.
• vegetation canopies, root zones, stomatal
  resistances

49
S. Stetson Houston GIS/RS zo input
Values are too large, as they were f(h) and not
f(oh) h building height
Values up to 3 m
50
Is extra work worth it? Below are Martilli uMM5
turbulence results
Non-urban
urban

• uMM5 results
• Day nite values are
• on same line ?
• small stability effects
• rooftop max matches
• Obs (blue dots)

51
uMM5 for Houston Balmori (2006)

• Goal Accurate urban/rural temps winds for Aug
  2000 O3 episode via
• uMM5
• Houston LU/LC urban morphology parameters
• TexAQS2000 field-study data
• USFS urban-reforestation scenarios ?
• UHI O3 changes

52
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At 2300 UTC summary of N-max ----?
54
uMM5 Simulation period 22-26 August 2000

• Model configuration
• 5 domains 108, 36, 12, 4, 1 km
• (x, y) grid points
• (43x53, 55x55, 100x100, 136x151, 133x141
• full-s levels 29 in D 1-4 49 in D-5 lowest ½
  s-level7 m
• 2-way feedback in D 1-4
• Parameterizations/physics options
• gt Grell cumulus (D 1-2) gt ETA or MRF PBL (D
  1-4)
• gt Gayno-Seaman PBL (D-5) gt Simple ice
  moisture,
• gt urbanization module NOAH LSM gt RRTM
  radiative cooling
• Inputs
• gt NNRP Reanalysis fields, ADP obs data
• gt Burian morphology from LIDAR building-data
  in D-5
• gt LU/LC modifications (from Byun)

55
Domain 4 (3 PM) cyclone off-Houston only on
O3-day (25th)
? Episode day
L
L
56
Urbanized Domain 5 near-sfc 3-PM V, 4-days
Hot
Cool

• Episode
• day

Cold-L
57
Along-shore flow, 8/25 (episode day) obs at 1500
UTC vs uMM5 (D-5) at 2000 UTC
D-5 (red box) uMM5 captured HGA obs of
along-shore flow (from SST- BC cold-low)
C
58
1 km uMM5 Houston UHI 8 PM, 21 Aug
UHI
UHI

• Upper L MM5 UHI (2.0 K)
• Upper R uMM5 UHI (3.5 K)
• Lower L (uMM5-MM5) UHI

MAX-?
LU/LC error
59
UHI-Induced Convergence obs vs. uMM5
OBSERVED
uMM5
60

• Base-case (current)
• veg-cover (0.1s)
• urban min (red)
• rural max (green)

min
Modeled changes of veg-cover (0.01s) gt
Urban-reforestation (green) gt Rural-deforestation
(purple)
max increase
61
Run 12 (urban-max reforestation) minus Run 10
(base case) near-sfc ?T at 4 PMreforested
central urban-area cools surrounding deforested
rural-areas warm
warmer
cooler
warmer
62
DUHI(t) Base-case minus Runs 15-18

• UHI Temp in Urban-Box minus Temp in Rural-Box
• Runs 15-18 urban re-forestation scenarios
• DUHI Run-17 UHI minus Run-13 UHI ?
• max effect, green line
• Reduced UHI ? lower max-O3 (not shown) ?
• EPA emission-reduction credits ? saved

63
RAMS, MM5, CAMx SIMULATIONS OF MIDDLE-EAST O3
TRANSBOUNDARY TRANSPORT

• E. Weinroth1,2, S. Kasakseh1,3
• M. Luria2, R. Bornstein1
• 1San Jose State Univ.
• 2Hebrew Univ. Jerusalem, Israel
• 3Applied Research Institute Jerusalem (ARIJ),
• Bethlehem, West Bank

64
Background

• USAID-MERC project (2000-)
• Scientists from Palestinian Territories, Israel,
  USA ( now Jordan and Lebanon)
• Objectives accomplished
• Installation of environmental monitoring stations
  in West Bank and Gaza
• Preparation of environmental databases (SJSU web
  page)
• Field campaigns during periods of poor air
  quality (Prof. Luria)
• Application of numerical models for planning
• RAMS MM5 (Kasakseh 2007) meso-met
• CAMx photochemical air-quality (Weinroth et al.
  2007 in Atmos. Environ.)

65
Rawinsonde z-t T(0C) section for July-August
1997solid line inversion base
66
Night obs of sfc flow 3-AM LST (00
UTC)
H

• Flow Dir weak down-slope off coastal-mountains
  at
• Coastal plain offshore (to W) from W-facing
  slopes
• Haifa Pen. (square) offshore (to E ) from
  E-facing slopes
• Inland sites directed inland (to E) from
  E-facing slopes
• Low-O3
• generally lt40 ppb)
• Haifa still at 51 ppb

L
L
67
Day Obs 1200 NOON LST
L

• Winds
• Reversed
• Stronger up 6 m s-1
• Coastal plain Onshore/upwind, from SW
• Inland sites Channeling (from W) in corridor
  (box) from Tel-Aviv to Jerusalem area (at Modiin
  site).
• Higher daytime O3
• max at Mappil, 66 ppb
• 2nd max at Modiin, 63 ppb

H
H
L
68
Obs, 7 AM, 1 Aug MM5 winds areall down-slope,
off-shore (except where inland-direct at inland
sites

• MM5 7 AM sfc winds (above)
• Off coast onshore from W (like ECMWF no obs)
• Coastal plain downslope/offshore from SSE
• (in obs RAMS cant be in coarser ECMWF)
• Inland sites inland directed (obs ECMWF)
• Southern obsMM5 are westerly RAMS was NW

69
Obs, 1 PM on 1 Aug All westerly/onshore flow

• MM5 1 PM sfc winds (above)
• Off coast onshore from W (like ECMWF no obs)
• Coastal plain upslope/onshore (in obs RAMS)
• Inland sites inland directed (in obs RAMS
• South (circle) NW (in RAMS Obs)

70
MM5 Configuration

• Version 3.7
• 3 domains
• 15, 5, 1.67 km Grid Spacings
• 59 x 61, 55 x 76, 58 x 85 Grid Points
• 32 s-levels
• up to 100 mb
• first full s-level at 19 m
• Lambert-conformal map projection (suitable for
  mid lat regions)
• Two-way nesting
• 5-layer soil-model
• Gayno-Seaman PBL
• Simulations
• End 00 UTC, 3 Aug
• Start 00 UTC, 29 July
• Single CPU , LINUX
• (SJSU-Lightning)

71
MM5 Domain-3 winds at 1100 LST on 1 August 1997
72
MM5 Domain-3 winds at 2300 LST on 1 August 1997
73
Mid-east Obs vs. MM5 2 m temp (Kasakech 06 AMS)
First 2 days show GC/Syn trend not in MM5, as
MM5-runs had no analysis nudging
Obs
Run 1
Run 4 Reduced Seep-soil T
July 29
August 1
August 2
obs
MM5Run 4
July 31
Aug 1
Aug2
Standard-MM5 summer night-time min-T, But lower
input deep-soil temp ? better 2-m T results ?
better winds ? better O3
74
Obs vs. MM5 V (m/s)
Note non-reproduced synoptic trend in max-speed
Run 3
OBS
July 31
August 1
August 2
75
RAMS/CAMx (left) O3 vs. airborne Obs (right) at
300 m gt Secondary-max over Jerusalem in obs
(but underestimated by 15) from coastal N-S
highway sources gt Primary-max found in Jordan
(no obs) from Hadera power-plant
Flight Path
Jerusalem
Irbid, Jordan
.
Hadera Power ? Plant
1 Aug, 1500 LST
76
Overall Modeling Lessons

• gt Models cant assumed to be
• perfect
• used as black boxes
• gt Need good large-scale forcing model-fields
• gt If obs are not available, OK to make reasonable
  educated estimates, e.g., for rural
• deep-soil temp
• soil moisture
• gt Need data to compare with simulated-fields
• gt Need good urban
• morphological data
• urbanization schemes

77
Thanks for listening!Questions?