Transcript Meteorological Conditions Associated with Major Storm

New York City Storm Surges:
Climatology and An Analysis of
the Wind and Cyclone Evolution
Dr. Brian A. Colle, Katherine Rojowsky, and F. Bounaiuto
School of Marine and Atmospheric Sciences
Stony Brook University, SUNY
Lidar image of business district of Manhattan showing
elevation and seawall locations (arrows). The imager
is flying above the Hudson River looking east.
(Photo Courtesy: NOAA/U.S/ Army JPSD)
3 September 1821: Only Major hurricane to hit
NYC directly (category 3)
The 1821 hurricane produced a storm
surge of 13 feet (4 m) in only one hour at
Battery Park. Manhattan Island was
completely flooded to Canal Street;
NYC area tracks obtained
by observations and
geological survey (Scileppi
and Donnelly 2007)
Tropical
Storm
Tracks:
1851-2005
Figure provided by J. I. Virmani, 2007
December 1992 Nor-easter
NARR Analysis
ADCIRC model hindcast of water
level ASL (m) using MM5 winds and
pressures at 18 UTC 12 Dec (Colle
et al. 2008)
(18Z 12 Dec 1992)
L
*
(6Z 13 Dec 1992)
*
L
12-13 December 1992 Nor-easter
Source: Metro New York Hurricane Transportation Study,
1995
Ref: Bloomfield, J., M. Smith and N. Thompson, 1999. Hot
Nights in the City. Environmental Defense Fund, New
York.
FDR Drive during the
December 1992 nor’easter
(Bloomfield, 1999)
Motivational Questions
• What is the variability of minor and moderate
storm surges and flooding events at NYC during
the past 50 years?
• How will the number of moderate flooding events
change as sea level rises during the next 50-100
years?
• How does the wind speed and direction evolve
around NYC for minor and moderate surge
events?
• What are the cyclone tracks and position at
maximum surge that favor storm surge events for
the NYC area?
Climatological Analysis of NYC
Surges
A minor and moderate surge at the
Battery that would result in a coastal
flood advisory and warning,
respectively, by the NWS during a
high tide (mean high water).
Minor: 0.60-1.00 m above MHW
Moderate: >1.00 m above MHW
Donna (’60)
(Gloria ‘85)
(’92 Nor-easter)
Maximum
daily surge at
the Battery,
NYC (1959 2007)
1960s
1970s
1980s
1990s
2000s
Number of Minor and Moderate Surge Events
Minor
Surge
Moderate
Surge
Monthly Minor Surge Events at the Battery, NY ‘59-‘07
Monthly Moderate Surge Events at the Battery, NY ‘59-‘07
Minor Surge Events at the Battery, NY ‘59-‘07
5 yr running mean
’72-‘73
’82-‘83
’97-’98
Monthly
Minor Surge
Annual
Moderate
SurgeEvents
Eventsatatthe
theBattery,
Battery,NY
NY‘59-‘07
‘59-‘07
Annual Observed Moderate Flooding Events at the Battery, NY ‘59-‘07
*Surge + tidal = total water level (storm tide)
NWS threshold Mod. Flooding = 2.44m above
Mean Low-Low Water (MLLW)
Moderate
observed
water level
flooding
events
absent after
1996
Impact of Sea-Level Rise on NYC Flood Events
IPCC (2007) 12-50 cm over next 50-100 yrs)
Observed Moderate Flooding Events
After 12.5 cm Sea-Level Rise
Impact of Sea-Level Rise on NYC Flood Events
IPCC (2007), 12-50 cm over next 50-100 yrs)
After 25 cm Sea-Level Rise
After 50 cm Sea-Level Rise
Impact of Sea-Level Rise on Minor Flood Events
(rise ~2.77 mm/yr at Battery--10-15 cm over 50 yrs)
Observed Minor Flooding Events
After Sea-Level Rise Correction
NWS threshold = 2.04 (minor flooding – coastal flood advisory),
2.44 (moderate flooding) above Mean Low-Low Water (MLLW)
Meteorological Analysis
• Datasets:
-- Hourly 10-m wind observations from Bennett’s
Field (1968-1971) and JFK airport (1973-2007).
-- NCAR-NCEP global (2 degree) reanalysis (19591978) Regional reanalysis (1979-2006)
• Approach:
-- For 191 minor and 31 moderate events after
1968, quantified the average wind evolution at JFK
and Bennett’s Field from 48-h before time of
maximum surge to 24-h afterwards.
-- Manually tracked cyclones within reanalysis for
surge events 0.8-1.0 and > 1.0 (2mb closed contour
for cyclone closest to NYC).
Wind Direction Evolution at JFK/Bennetts
Wind Direction -48/+24h Surrounding Maximum Surge
Minor
Speed &
Direction
Frequency at
Time of
Maximum
Surge
Speed (m/s)
Minor
Moderate
Time
of max
surge
Wind Speed Evolution at JFK
Wind Speed -48/+24h Surrounding Maximum Surge
Distribution of Wind Speeds at
Maximum Surge
Time
of max
surge
Minor Surge Cyclone Tracks -48/+12h
Cyclone Tracks
0.8-1.0 m events
Position at Time of Max Surge
0.6-1.0 m events
48oN
o
44 N
40oN
*
o
36 N
o
32 N
o
84 W
o
78 W
o
72 W
o
66 W
Number of Cyclone Centers
9 6 5 4 3 2 1
o
60 W
Moderate Surge Cyclone Tracks -48/+12h
Cyclone Tracks
Position at Time of Max Surge
1.0 m events
1.0 m events
*
Number of Cyclone Centers
9 6 5 4 3 2 1
NCEP Reanalysis SLP Composite of 46 > 1-m Surges at Battery, NY
-36 h
-24
h
-24h
H
H
L
-12 h
0h
H
H
L
L
NCEP Reanalysis 500Z Composite of 46 > 1-m Surges at Battery, NY
-36 h
-24 h
-12 h
0h
Tropical Storm Surge Tracks (19592007)
Conclusions
• Large inter-annual & inter-decadal variability. Minor
surge events more prevalent during the 60’s, 70’s &
mid-90’s. Only 1 moderate surface event since 2000
and no observed moderate flooding events since
1996.
• A 10-15 cm sea-level rise over last 50 years has
increased the number of minor flood events (given
coastal flood advisory threshold by NWS).
• Flooding (even for nor-easters) will increase
dramatically as sea level rises 10-50 cm over the next
50-100 years.
• Moderate event mean wind speeds 25% greater at the
time of maximum surge than minor events. Wind
speeds in isolation not a good predictor of minor vs.
mod surge.
• Diverse tracks for minor & moderate, with moderate
tending toward the coast (Miller Type A track).