Air-Sea Interaction in NYC: Air-Sea Interaction in NYC: Urbanized Mesoscale Modeling for CB Urbanized Mesoscale Modeling for CB ThreatsThreats

with Alan Blumberg, SIT

& Bob Bornstein, SJSU

Julie Pullen & Teddy HoltJulie Pullen & Teddy HoltNaval Research LaboratoryNaval Research LaboratoryMonterey, CAMonterey, CA

03 UTC 09 UTC 15 UTC 24 UTC

Motivation: Motivation: Ocean & Urban Ocean & Urban Impacts Impacts

Local SST gradients due to urban Local SST gradients due to urban discharges (such as power plants), discharges (such as power plants), river discharges and coastally river discharges and coastally upwelled water can alter overlying upwelled water can alter overlying atmosphere (e.g., sea breeze fronts)atmosphere (e.g., sea breeze fronts)

Building morphology and Building morphology and heating effects from urban heating effects from urban areas impact the weather areas impact the weather and contaminant dispersionand contaminant dispersion

Mesoscale OverviewMesoscale Overview COAMPSCOAMPS®®: data-assimilating modeling system: data-assimilating modeling system 5 nests (36 km to 0.44 km)5 nests (36 km to 0.44 km) urbanization and time-varying (hourly) realistic SSTs on urbanization and time-varying (hourly) realistic SSTs on

nests 4 (1.33 km) & 5 (0.44 km)nests 4 (1.33 km) & 5 (0.44 km)

sea breeze forecast (nest 5)

0

hurb (m)

50

150

200

100

N S0

0.2

0.1

Lower Manhattan

Midtown

StatenIsland

58.5 km

North-South cross-section

Bu

ild

ing

he

igh

t A

GL

(km

)

N

S

Midtown Manhattan

BrooklynStatenIsland

Model Configuration

nest 1 (36 km) nest 2 (12 km) nest 3 (4 km) nest 4 (1.33 km) nest 5 (0.44 km)

1

2

34

Nests 4 & 5 use an urban canopy parametrization and hourly time-varying model-derived SSTs

Observed SST

nest 4 (1.33 km)

nest 5 (0.444 km)

control SST

control SST

model SST

model SST

Realistic High-Resolution SSTs

13 UTC July 4 to 12 UTC July 9

Upwelling-favorable Wind Regime

Plumb Beach

ALSN6Sandy Hook

Wind speed (m/s) N mean standard dev

Plumb Beachobserved

uses control SSTuses model SST

120120120

2.995.154.89

1.351.771.60

Sandy Hookobserved

uses control SSTuses model SST

120120120

4.564.944.72

2.011.551.54

ALSN6observed

uses control SSTuses model SST

120120120

6.387.186.80

2.432.552.64

Wind speed (m/s) MB RMSE CC

Plumb Beachuses control SSTuses model SST

-2.16-1.90

2.792.50

0.380.39

Sandy Hookuses control SSTuses model SST

-0.38-0.16

1.861.75

0.490.54

ALSN6uses control SSTuses model SST

-0.80-0.42

2.282.25

0.630.62

13 UTC 4 July - 12 UTC 9 July, 2004 (5 days)

Model/Observation Statistics

Modification of Urban Heat Island

Offshore Wind Regime

COAMPS® NYC Nest 5 (0.444 km)

10-m winds; 2-m air temperature (C)12-h forecast valid 00 UTC 5 Aug 2004

JFK

LGA

Winds every 5th grid point

Subset: Winds every grid point

JFK

LGA

ALSN6

NYC Mesoscale ModelingNYC Mesoscale Modeling