NOAA’s National Ocean Service • Office of Response and Restoration
Use of Operational Forecast Systems
in Oil Spill Trajectory Modeling
Amy MacFadyen and Glen Watabayashi
Emergency Response Divison,
NOAA/NOS/OR&R
Outline
• About the Emergency Response Division
(formerly NOAA HAZMAT)
• Physical processes in oil movement
• Trajectory forecasting of oil spills
• Use of (operational) Nowcast/Forecast
systems
Origins of NOAA HAZMAT program
1976 Argo Merchant
• On December 15, the tanker
grounded near Nantucket Island
over Georges Bank carrying ~7.5
million gallons of heavy fuel oil
• NOAA began its first major
coordinated oil spill response
activity
 NOAA Hazardous Material Response Division was created to
provide scientific expertise during a response incident
Origins…
1989 Exxon Valdez
• March 24 grounding in Prince
William Sound resulting in spill of
11 million gallons of crude oil
• NOAA HAZMAT team supported
the massive cleanup and damage
assessment by providing forecasts,
guiding aerial obs, making
recommendations on cleanup
actions and monitoring recovery
 Prompted congress to enact the Oil Pollution Act (OPA) of 1990
giving NOAA greater ability to respond to spills and creating a trust
fund financed by oil tax to aid in cleanup operations
Emergency Response Division
• under the National Contingency Plan,
NOAA has responsibility for providing
scientific support to the Federal OnScene Commander (FOSC) for oil and
hazardous material spills
• ERD provides 24-7 response to spill
events
• ERD’s scope encompasses the entire
U.S. coastline, including the Great
Lakes, Alaska, Hawaii and U.S.
territories
How many spills are there?
Spill Calls (1999-2009)
250
Oil
Chemical(s)
Miscellaneous
200
150
100
50
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Incident Command Structure
• Scientific Support Coordinators
are staff advisors to Federal OnScene Commanders responsible
for coordinating the scientific
aspects of spill response
• a team of ERD scientists, support
the SSCs during spill events, as
well as in drills and contingency
planning
– shoreline assessment, biological and
resource assessment, weather
forecasts, overflights, data
management, communications,
protection/cleanup
recommendations and priorities
What happened?
Where will it go?
What will it hit?
How will it hurt?
What can be done?
What happens to oil spilled at sea?
• Oil spill trajectory forecasts
must consider the physical
processes describing both
the fate and the transport of
oil released into the
environment
–
–
–
–
Spreading
Advection
Dispersion and mixing
Weathering
From ITOPF report (www.itopf.com)
Processes in Oil Weathering
hours
days
weeks
years
time
•
•
•
•
•
•
•
•
Spreading
Evaporation
Dispersion
Dissolution
Emulsification
Photo-oxidation
Sedimentation
Biodegradation
Transport processes
• horizontal advection
– Surface currents and wind drag
– empirical studies demonstrate that
surface slicks are transported with the
surface current at 3-4% of the wind
speed



Ur  V  KwU w
• oil is dispersed horizontally by
turbulence field
• oil is also transported vertically in
the water column in the form of
droplets of various size
– recent work has demonstrated that this
vertical movement is important not
only for mass balance calculations, but
also in determining the spatial and
temporal distribution of oil on the sea
surface
 both vertical and horizontal current
shears are important factors in the net
motion of oil at sea
Trajectory forecasting
ADIOS2 + GNOME
AK North Slope Crude
Diesel
Five day oil budget – 20 kt winds, 0.5 kt currents
Showing amount evaporated, dispersed, remaining
Trajectory forecasting
ADIOS2 + GNOME
• Lagrangian-Eulerian spill
trajectory model
• Spills are modeled as
Lagrangian particles within
continuous Eulerian fields
• Surface wind effects (wave
stress, wave compression,
Stokes drift, dispersion, overwashing, surface drift and
Langmuir circulation) are
combined into “Wind Drift”
parameter
• Simple weathering algorithms
• Limited 3D capability
Data sources for ocean currents
--in house response model-• linear, shallow
water equations
• barotropic
• steady-state
• easily relocatable and can be
set up and run very quickly
• simplified physics
Data sources for ocean currents
--external forecast models-• Navy operational models
– NCOM, NLOM, HYCOM
• NOAA operational models
– NWS RTOFS Atlantic Basin model
– CSDL/COOPS models
• State agency run models
– Texas General Line Office (TGLO) Gulf of Mexico
• IOOS Regional Associations
Prince William Sound
(JPL)
Oregon (OSU)
Mid Atlantic Bight
(Rutgers)
ROMS Hawai’i (UH)
Southern CA Bight
(JPL)
Gulf of Mexico
(TAMU/TGLO)
ROMS models for US coastal waters producing
Nowcast/Forecast currents
Considerations for use of currents from
external models in trajectory forecasting
Recent (March 2010) Examples
from ResponseLink
1. Forecast for current/ongoing
spills
2. Hindcast requests
3. Assessing threats from known
sources
4. Assessing threats from
hypothetical sources/spills
1. Response to current/ongoing spill
Scenario:
At approximately 1800 hrs on 25
March 2010, USCG Marine Safety
Unit Morgan City notified the NOAA
Scientific Support Coordinator of a
10 mile by 3 mile slick located
roughly 20 miles SSW of Caillou Bay
and the Louisiana Coast. The NRC
Report stated that 951 bbls spilled
based on an estimation (probably
based on a sheen calculation for
dark oil).
951 bbls = ~40,000 gallons
1. Response to current/ongoing spill
Response:
In the first hour of the spill:
• Weather forecast, tide forecast,
oil fate prediction
• Initial trajectory passed verbally
by phone and followed by written
report
2 - 4 hrs after initial call:
• Computer model setup and run
• Forecast 24-48 hours
Day 2 after initial call
• Away Team goes on-scene
• Model recalibrated and run daily
Considerations for using currents from
operational model
• Access – immediately available at
any time
• Format – easily loaded into GNOME
• Validation – should we believe the
forecast
• Point of contact – is there someone
we can call with questions
1. Response to current/ongoing spill
TGLO ROMS model
•
•
•
Developed at TAMU and run
operationally by TGLO
Forecast images and data easily
available through website
Output is available in GNOME
ready format
http://seawater.tamu.edu/tglo/rindex.html
2. Hindcast requests – “Where did this [body, dead whale,
medical equipment, bale of cocaine…] come from?”
Scenario:
On 18 March 2010, NOAA
Emergency Response Division was
notified by USCG Sector Guam, via
email, of tarballs coming ashore at
Ritidian Point-on the island's
northern end. (13° 39.5'N by 144°
51.8'W). NOAA Scientific Support
Team was requested to provide a
hindcast trajectory to help better
evaluate possible sources.
Specifically: what is the likelihood
of pollution source originating
from the northern islands?
2. Hindcast requests – “Where did this [body, dead whale,
medical equipment, bale of cocaine…] come from?”
Response:
• Written analysis
summarizing findings
within ~24 hours
Considerations for using currents from operational model
• Access – usually not as urgent but may need previous several days
• Format – have more time to make GNOME ready
• Validation – may be able to corroborate model results with current meter or
HF radar data
3. Potential threats from known sources
Scenario:
The SS Princess Kathleen is a wellknown wreck in the Juneau area,
which sunk on Sept. 7, 1952. From a
time shortly after her sinking to today,
she has been leaking fuel oil into the
surrounding waters. Recent increases
in the sightings of small oil blobs in the
area of Lena Pt. resulted in Sector
Juneau's decision to seriously evaluate
the wreck for possible removal of the
remaining fuel, which is very roughly
estimated at 155,000 gallons of bunker
C…
Global Diving tentatively hopes to start
pumping oil on or about March 5.
NOAA has been asked to provide
weather and trajectory support for this
incident.
3. Potential threats from known sources
Response:
• Written analysis summarizing findings within
days to weeks
• Most likely impacted regions under typical
(seasonal, event-scale) forcing scenarios
• Worst case scenarios
• Results may direct the field response – ie
when is best time for pumping operations
Considerations for using currents from operational model
• Access – in order to do statistical analysis may need multiple years of output
• Format – have time to make GNOME ready but may involve very large
datasets
• Validation – does model reasonably represent variability of real system
Utility of external models in spill response
• Needs depend on type of request
• In general, output must be rapidly accessible in standardized
format
– New technologies make this much
less of a hurdle (e.g. NetCDF, NcML,
OpeNDAP)
• in most cases model output will
still require some pre-processing
before import into GNOME
Stolen from Rich Signell
GOODS website
• Inventory of accessible
oceanographic and
meteorological sources
• Allows quick extraction,
subsetting and produces
output that can be
quickly loaded into
GNOME
• Trajectory modelers can evaluate
results from a suite of inputs and
generate a consensus forecast
• Uncertainty estimates
Summary
• Proliferation of Nowcast/Forecast models, observing
system components and new technologies enabling
interoperability increasingly allow us to use multiple
model and data sources for oil spill trajectory
forecasting
• Using output from state-of-the-art regional models is
possible during early stages of spill response only if
contacts have been made prior to the spill
Mahalo!
http://www.weather.com