Advanced Hurricane Prediction

A plan for research and development

Naomi Surgi

February, 2005

Requirements Process

Societal Impacts:• More people living along coastal areas –

takes longer to evacuate• Evacuations are costly: ~$1M per mile of

coastline evacuated• Evacuation numbers depend on hurricane

size and intensity• More hurricane related fatalities now due to

inland flooding

Stakeholder Requirements• Improved track forecast skill – where and

when?

Extend track forecasts out to 5 days

• Improved hurricane intensity forecasts

intensity at landfall – how strong?

onset of gale force winds at coastline (structure) – how big & when?

• Skillful heavy rainfall forecasts out to 3 days in advance

• Continued advancement of TC track forecasts

• Improved TC intensity prediction (genesis and

rapid intensification)

• Improved prediction of TC surface wind

distribution (structure)

• Improved rainfall forecasts

• TC waves, storm surge

Operational TC Forecast Issues:

TPC Atlantic 72-hr Track Forecast Errors

With the exception of “erratically” moving storms, while hurricane track prediction has shown remarkable progress, skill in predicting intensity/ structure changes is still poor. It is expected that high resolution, advanced NWP modeling systems may continue to improve track as well as intensity, structure predictions. Hurricane WRF is the next step towards this goal.

Lowest track errors on record for GFS, GFDL models and TPC!

How NOAA Improved Track Forecasts

• HIGH QUALITY OBSERVATIONS (large scale environment surrounding hurricane, e.g. satellite, aircraft)

• MADE BETTER USE OF OBSERVATIONS IN HURRICANE MODELS (advances in data assimilation)

• IMPROVED HURRICANE MODELS (improved numerical techniques and representation of physical processes)

Three components of modeling system:

Advanced Data Platforms for Hurricanes

Environment: (Winds, Moisture, Temperature) – to define steering currents

• Satellite: Advanced Satellite Instruments

(AMSU, GOES, NPOESS etc.)

• In-situ: Aircraft (dropsondes)

NCEP Global Forecast System 6 hr Forecast and WV Imagery

Jung and Zapotocny

JCSDAFunded by

NPOESS IPO

Satellite data ~ 10-15% impact

Impact of Removing AMSU, HIRS, GOES Wind, Quikscat Surface Wind Data on Hurricane Track Forecasts in the Atlantic Basin - 2003 (34 cases)

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

12 24 36 48 72 96 120

Forecast Hour

% Improvement

NOAMSU

NOHIRS

NOGOESW

NOQuikscat

Impact of Removing AMSU, HIRS, GOES Wind, Quikscat Surface Wind Data on Hurricane Track Forecasts in the East Pacific Basin - 2003 (24 cases)

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

12 24 36 48 72

Forecast Hour

% Improvement

NOAMSU

NOHIRS

NOGOESW

NOQuikscat

Synoptic Surveillance

Pattern

Note: Improved skill at all forecast times in 2002 and 2003

Impact Of Dropsondes On NCEP Global Model Track Forecasts

Intensity Guidance

Most skillMost skill

930

940

950

960

970

980

990

1000

1010

1020

8/9 8/10 8/11 8/12 8/13 8/14 8/15 8/16

Hurricane Charley Minimum Central Pressure9 - 14 August 2004

BEST TRACK

Sat (TAFB)

Sat (SAB)

Sat (AFWA)

Obj T-Num

AC (sfc)

Surface

Pressure (mb)

Date (Month/Day)

Charley deepened From 964 mb to 941 mbin 4 h 35 min nearlandfall – NIGHTMARE!

• ENVIRONMENTAL FORCING

• “good vs. bad” trough interactions

• SST changes (including ocean subsurface)

• CONVECTIVE SCALE PROCESSES

• total rainfall – organization of convection, eyewall vs. Stratiform

• MICROPHYSICS – LIQUID VS. ICE

• INNER CORE REGION

• scale interaction – feedback between vortex dynamics, convective physics and environment

• triggering and adjustment processes – eyewall replacement cycles, eyewall mixing

Science Issues to address Intensity/Structure

• AIR SEA INTERACTION: OCEANIC/ATMOSPHERE BOUNDARY LAYER)

• Air sea fluxes under disturbed conditions (sea spray)

• Turbulence and subgrid scale mixing

• Coupled atm/ocean model; coupled wind-wave model

• UPPER OCEAN PROCESSES

• SST changes – depth of warm layer (accounts for turbulent mixing, horizontal advection) e.g. Gulf Stream and loop currents, warm core eddies, cold wakes

• LAND SURFACE PROCESSES

• PBL fluxes – storm structure -- coupling to hydrologic processes

Science Issues – con’t

To advance TRACK forecasts AND improve INTENSITY, STRUCTURE and RAIN Forecasts:

• Need high quality hurricane core* and environmental observations

• Need advanced data assimilation techniques for environment and hurricane core

• Need advanced modeling system

• Need a “disciplined” approach for transition from research to operations, e.g. JHT, JCSDA

* critical observations for intensity/structure and rain problem

Advanced Observation Platforms for Hurricanes

• Environment (Winds, Moisture, Temp.)

In-situ: G-IV, UAV’s, Driftsondes

Satellite: ADVANCED MICROWAVE INSTRUMENTS

• Hurricane Core (Winds from 12 km to surface)

G-IV, WP-3D airborne Doppler radars

88-D Level II data

• Upper Ocean (SST’s, wave height, mixed layer info)

AXBTs, Altimeter, ARGOS, Current Meter, Buoys

Required Data Assimilation Development

•Advanced Data Assimilation Techniques

Environmental flow – in progress (some success)

Hurricane Interior - substantial R&D necessary*

Ocean data assimilation – new effort (GODAS)

* EMC is developing scale-dependent covariances

Hurricane WRF (HWRF) Prediction System

• Community based next generation hurricane prediction system

• Will replace the GFDL in 2007

• Coupled air-sea-land prediction system

• Advanced data assimilation for hurricane vortex

• Advanced physics for high resolution

• Land surface coupled to hydrology/inundation

• Nested wave prediction

• Coupling to dynamic storm surge (in planning)

GFDL

MM5

02 03 04 05 06 07

Begin Physics Upgrades

Mesoscale Data Assimilation for Hurricane Core

Preliminary Test

HWRF physics

HWRF

T&EHWRF

HWRF Operational

GFDL frozenHWRF T&E

TRANSITIONING TO HURRICANE WRF

Begin R&D

Transition to HWRF

Continue upgrades

Pre-Implementation Strategy for HWRF INCREASE RESOLUTION

UPGRADE GFDL PHYSICS WITH GFS PHYSICS

IMPLEMENT MICROPHYSICS, SFC. PHYSICS

PUT PHYSICS IN WRF FRAMEWORK

MIGRATE ALL PHYSICS TO NMM, e.g. HWRF

CARRY OUT TEST & EVALUATION ON UPGRADED GFDL SYSTEM (GFDL FROZEN ’05-06)

PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND HWRF FOR MULTIPLE SEASONS AND STORMS

DEVELOPMENT OF THE HWRF SYSTEM

Movable, nested grid (configuration, domain)

Advancement of physics (wheel of pain)

Initialization (development of DA for hurricane vortex) (LONG TERM EFFORT)

Coupling to HYCOM

Coupling to WAVEWATCH III (+ multi-scale model)

Coupling to LSM

Development/Upgrade of hurricane verification system (PPT, STRUCTURE)

Coupling to storm surge-wave coupled model (planning stage)

HWRF ensembles

“THE PHYSICS WHEEL OF PAIN”

Radiation

Cu SchemeSfc & PBL

Grid Scale Microphysics

1. - Hydrometeor type (phase)

- Cloud optical properties

- Cloud overlap (merging Cu, grid-scale cloudiness)

- Cloud fractions

2. - Precipitation

3. - Sfc energy fluxes

4. - Convection, PBL evolution, precipitation

Compliments of Dr. Jaiyu Zhou (NOAA/OST)

Hurricane-Wave-Ocean-Surge-Inundation Coupled Models

High resolution Coastal, Bay & Estuarine hydrodynamic model

HWRF

Atmosphere/oceanic Boundary Layer

HYCOM3D ocean circulationmodel

WAVEWATCH IIISpectral wave model

NOAH LSM

NOSland and coastal waters

NCEPAtmosphere and Ocean

runoff

fluxes

wave fluxes

wave spectra

windsair temp. SST

currents

elevations currents3D salinities temperatures

other fluxes

surgeinundation

radiativefluxes

HYCOM Expt – Hurricane Isabel MODEL:

– HYCOM Mercator North Atlantic 1/12 degrees (∆x ≈ 7 km).

– 26 vertical coordinates.

– Vertical viscosity and mixing: GISS.

+ FORCING: 6-h NCEP (GFS analysis).

INITIAL CONDITIONS: from near-real time North Atlantic system (NRL & RSMAS) (O.M. Smedstad).

PERIOD: Sept. 3-30, 2003

SSH and cross section positioning

∆H~30 cm

Temperature cross sections for Sept 11, 15-21, 30

GFDL Coupled Model

C-BLAST BUOYS DURING FRANCES

Hurricane Frances – impact of couplingBlue- GFDL operational coupled modelRed- GFDL uncoupled model

The Future

Deep ocean model resolution dictated by GFS

model

Higher coastal model resolution dictated by

model economy

Highest model resolution in areas of special interest

Hurricane nests moving with storm(s) like GFDL and HWRF

Joint Hurricane Testbed

Mission Statement:

The mission of the JHT is to transfer more rapidly and smoothly new technology, research results, observational and model advances into improved tropical cyclone analyses and prediction at operational hurricane forecast centers.

Technology Infusion