Title: Urban Boundary Layer interactions with weather, air quality, and climate change processes
1Urban 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
2OVERVIEW
- 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
3URBAN 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
4HUMAN-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)
5NEW URBAN CLIMATE CAUSES
- GRASS SOIL ?
- CONCRETE BUILDINGS ?
- ALTERED SURFACE HEAT FLUXES
- FOSSIL FUEL CONSUMPTION ?
- ATMOSPHERIC POLLUTION AND HEAT
- ATM POLLUTION?
- ALTERED SOLAR IR ENERGY
6St. Louis nocturnal PBL warm near-neutral,
polluted, urban-plume vs. rural stable
surface-inversion
0F
urban-plume
inversion
Clark McElroy (1970)
7Urban 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)
8NYC DAYTIME ?V (z)
urban
rural
9URBAN 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
10NOCTURNAL 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
12NYC 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 ?
14URBAN 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
15NYC 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
16Dispersion 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
17Urban-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
18California 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)
19Not much change from mid- 40s to mid-70s, when
values started to again rapidly rise
20Statistically 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
21Earlier 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)
22The 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
?
23CURRENT 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
24Results 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
?
?
?
25Results 2 SFBA CV 1970-2005 JJA Tmax
warming/cooling trends (0C/decade), as in
previous figure
?
?
?
26(No Transcript)
27Significance 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
28(No Transcript)
29(No Transcript)
30Note IPCC 2001 does show cooling over Central
California!!
31Significance 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
32Trend 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)
33Result 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
34Result 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)
-
35Notes 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
36BENEFICIAL 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
37NAPA WINE AREAS MAY NOT GO EXTINCT DUE TO ALLEGED
RISING TMAX VALUES, AS PREDICTED IN NAS STUDY
38Result 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
39Future 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
40POSSIBLE 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
41OUR 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)
42SJSU 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
43Case 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
44Case 2 ATLANTA UHI-INITIATED STORM OBS SAT
PRECIP (UPPER) MM5 ws precip (LOWER)
45Recent 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)
48But, 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
49S. 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
50Is 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)
51uMM5 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(No Transcript)
53At 2300 UTC summary of N-max ----?
54uMM5 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)
55Domain 4 (3 PM) cyclone off-Houston only on
O3-day (25th)
? Episode day
L
L
56Urbanized Domain 5 near-sfc 3-PM V, 4-days
Hot
Cool
Cold-L
57Along-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
581 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
59UHI-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
61Run 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
63RAMS, 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
-
64Background
- 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.)
65Rawinsonde z-t T(0C) section for July-August
1997solid line inversion base
66Night 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
67Day 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
68Obs, 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
69Obs, 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)
70MM5 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)
71MM5 Domain-3 winds at 1100 LST on 1 August 1997
72MM5 Domain-3 winds at 2300 LST on 1 August 1997
73Mid-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
74Obs vs. MM5 V (m/s)
Note non-reproduced synoptic trend in max-speed
Run 3
OBS
July 31
August 1
August 2
75RAMS/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
76Overall 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
77Thanks for listening!Questions?