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National Report (NOAA/NCEP). RTOFS, CFS, SST, sea ice. Hendrik L. Tolman Chief, Marine Modeling and Analysis Branch NOAA / NWS / NCEP / EMC [email protected] intro. The bigger pictures: Representing NCEP here, not necessarily all of NOAA: GFDL ocean modeling in climate realm.

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National report noaa ncep

National Report (NOAA/NCEP)

RTOFS, CFS, SST, sea ice

Hendrik L. Tolman

Chief, Marine Modeling and Analysis Branch

NOAA / NWS / NCEP / EMC

[email protected]


Intro

intro

  • The bigger pictures:

    • Representing NCEP here, not necessarily all of NOAA:

      • GFDL ocean modeling in climate realm.

      • AOML push to do ocean OSSEs.

    • Mandate within NOAA to build NOAA part of a national ocean modeling backbone capability (real time and short term forecast focus?):

      • A part of a larger national backbone capability with main contributions from Navy, and many other partners.

      • Within NOAA:

        • NCEP : global focus:

        • NOS: National coastal focus (Coastal Ocean Modeling Framework).

        • IOOS RA’s regional focus.


Intro1

intro

  • Cont’ed:

    • Second focus for us on ocean-weather link.

      • Hurricane forecast problem.

      • General weather prediction.

        • NCEP focus on short term weather up to annual.

        • Seamless model suite approach (see next slide).

    • Resources:

      • Funding remains issue, hurricane helps (HFIP).

      • Building capability.

      • HYCOM consortium.

    • Stand-alone SST and ice products.

    • GODAS in CFS ongoing GODAE contribution.

    • Ecosystems Modeling Enterprise in NOAA a 20 year plan under development.


Intro2

intro

Executing the weather-climate strategy

Adapt this vision to ocean modeling.

Add ocean to each time scale.


Intro3

intro

  • Ocean modeling at NOAA – NCEP ; Eddy-resolving real-time short term forecasting ; Real Time Ocean Forecast System (RTOFS).

    • HYCOM based (part of HYCOM consortium).

    • Jan. 2007 workshop identified four focus areas for NCEP:

      • Eddy resolving modeling (1) and model initialization (2).

        • RTOFS – Atlantic

        • RTOFS – Global

      • Coupled high-resolution modeling of hurricanes (3).

        • RTOFS - HWRF ( - WAVEWATCH IIITM) coupling.

      • Coupled modeling of weather in general (4).

        • Coupled CFS for reanalysis and re-forecasting (GFS + MOM4 from GFDL, GODAS).

        • GFS + HYCOM ? Low hor. res., high vert. res.


Rotfs atlantic

ROTFS-Atlantic

  • 1/12º resolution Real Time Ocean Forecast System for North Atlantic Ocean. (RTOFS-Atlantic, HyCOM based).

    • Deterministic 6 day forecast (including tides, 3h forcing).

    • Assimilation of most available data with in-house assimilation schemes (2+1D Var, recursive filtering).

    • Run once per day.

  • Presently in bad shape, issues are dealing with operations, not with science:

    • Most difficult computer update in decade results in nine-month upgrade moratorium.

    • Weather operations practices versus ocean needs.

      • Data density and impacts for assimilation approaches.

        • Re-initializations, interactive QC.

In queue for summer upgrade


Rtofs global

RTOFS-Global

  • Global eddy resolving model needed at NCEP for various reasons:

    • Provide OPC with suitable guidance.

    • Key element of NOAA and national backbone capability.

      • NCEP – NOS – IOOS strategy.

      • Address boundary issues with RTOFS - Atlantic.

      • Enable local coupled modeling for hurricanes at NCEP.

        • Focus on North Atlantic and North East Pacific, but enable globally as needed (unified model approach).

      • Enable ecosystems modeling in general.

    • NOAA mandate dating from 2005. Gap needs to be filled,

    • Resources:

      • Compute, storage, visualization and analysis,

      • Human.


Rtofs global1

RTOFS-Global

  • Cont’ed:

    • Leverage HYCOM consortium work to accelerate filling gap.

      • Adopt Navy 12° global HYCOM model as starting point.

        • 2009 computing resources sufficient to run model, not sufficient to fully support initialization.

          • Run model with NCEP forcing and Navy initialization, daily 6 day forecast.

          • Operational data feed being established.

          • Visualization and validation is an issue.

        • 2012 computing resources to fully support system.

          • NCEP self contained initialization.

          • Envision close collaboration with Navy in development of assimilation / initialization.

        • 2014+ decision needs to be made to go to higher global resolution or regional US resolution.


Hwrf hycom

HWRF-HYCOM

  • Coupled HWRF-HYCOM system:

    • Ocean state is important in hurricane track and intensity forecasting:

      • SST (26°C cut-off).

      • Depth of mixed layer, temperature gradient below.

      • Operational system uses “ad-hoc” POM mode.

    • HWRF-HYCOM system designed to fit into operational RTOFS-Atlantic model.

      • Full 3D ocean model.

      • Realistic initialization from operational RTOFS-Atlantic.

    • Goals and time lines:

      • Parallel testing 2009 Atlantic Hurricane season.

      • Working on adding wave coupling (WAVEWATCH III), to be tested in parallel operations 2010 or 2011.


National report noaa ncep

Coupled HWRF- HYCOM system

RTOFS-Atlantic

(HYCOM–Basin):

O(4~17 km)

IC

BC

GFS:O(25 km)

Data Assimilation (SST, SSH, T&S) using 2D/3DVAR

meld

Feature Model Wind

SST

ATMOS.:

HWRF

O(9 & 27 km)

OCEAN:

HYCOM–Regional:

O(8~14 km)

* Wind-stress

*Heat Fluxes

*Precipitation

*Atm. Pressure


National report noaa ncep

Example of coupled simulations conducted for 2008

Simulation

for

Katrina

Compared with

Animation of hourly GOES SST 3-day moving average

(http://svs.gsfc.nasa.gov/vis/a000000/a003200/a003222/index.html)


Hwrf hycom1

subinertial waves

Cold wake

HWRF-HYCOM

Real time testing for 2008 hurricane season (Ike).

Realistic oceanic simulation and response to a storm!


Hwrf hycom2

HWRF-HYCOM

  • Focus areas for model development:

    • First and foremost this is a hurricane forecast problem:

      • Hurricane track and intensity

    • Sustained progress can only be made with solid science.

      • Evaluate ocean model skill to accurately represent processes of interest.

      • Evaluate hurricane forecast system to provide accurate air-sea fluxes.

      • Evaluate the ability of observations and data assimilation to accurately represent initial conditions in regions and for state variables of interest.


Hwrf hycom3

Katrina

Rita

Kyle

Gustav

HWRF-HYCOM

Track errors

Black – HYCOM

Red – Ops (POM).

Mean Difference is at the same order of magnitude;

Variations are consistently smaller


Hwrf hycom4

Katrina

Rita

Gustav

Kyle

HWRF-HYCOM

Intensity errors

Mean Difference is at the same order of magnitude;

Variations are consistently smaller


Hwrf hycom5

Position

Time

HWRF-HYCOM

A

Size: 34-kt

SST cooling varies locally, what will be a good metric for cooling:

local

area

footprint

6-hour after

B

6-hour before


Hwrf hycom6

HWRF-HYCOM

R<=34-kt

R<=50-kt

ΔSST ~0.8oC

R=150-km

ΔSST ~0.4oC

ΔSST ~0.7oC

The Size of the footprint matters!


Hwrf hycom7

150-km

34-kt

HWRF-HYCOM

Examples of fluxes and averaging radii for metrics …


Hwrf hycom8

HWRF-HYCOM

Pre-storm survey (Gustav)

Model: warmer SST and deeper MLD, Z26 and Z20  IC


National report noaa ncep

Current Operational GODAS

  • Operational in 2003.

  • Based on MOMv3 (1o x 1o, 1/3o in the tropics, 40 lvls) and a 3DVAR assimilation scheme.

  • The assimilation data are temperature profiles (XBT, Argo, TAO, TRITON, PIRATA), synthetic salinity profiles derived from a climatological T-S relation and Jason-1 altimetry (March 2007). The data window extends from 2-weeks before to 2-weeks after the analysis date.

  • Atmospheric forcing from the NCEP Reanalysis-2, surface relaxation to Reynolds weekly OIv2 SST, Levitas climatological SSS.

  • Ocean reanalysis (1980-present) providing initial conditions for retrospective CFS forecasts used for calibration.

  • Two versions associated with the CFS: 14-day lag, 1-day lag.

  • A third stand-alone version with a 14-day lag.


National report noaa ncep

Ocean Model

MOMv3

quasi-global

1ox1o (1/3o in tropics)

40 levels

Climate

Forecast

System

(CFS)

Atmospheric Model

GFS (2003)

T62

64 levels

Reanalysis-2

3DVAR

T62L28

update of the

NCEP-NCAR R1

GODAS

3DVAR

XBT

TAO etc

Argo

Salinity (syn.)

TOPEX/Jason-1

Current Operational SI Prediction at NCEP


National report noaa ncep

Next Generation GODAS in the CFSRR

  • To become operational in 2010.

  • Based on MOMv4 (1/2o x 1/2o, 1/4o in the tropics, 40 lvls) and an updated 3DVAR assimilation scheme.

  • Assimilation data are temperature profiles (XBT, Argo, TAO, TRITON, PIRATA), synthetic salinity profiles derived from a seasonal T-S relation, and TOPEX/Jason-1/Jason-2 Altimetry. The data window is asymmetrical extending from 10-days before the analysis date.

  • Surface temperature relaxation to (or assimilation of) Reynolds new daily, 1/4o OIv2 SST, surface salinity relaxation Levitas climatological SSS.

  • The analysis system is coupled to the CFS in the sense that the first guess for the assimilation is provided by the CFS. After each analysis cycle the ocean model is stepped forward as a fully coupled component of the CFS.

  • The current stand-alone operational GODAS will be upgraded in 2009 to the higher resolution MOMv4 and be available for comparison with the coupled version.


National report noaa ncep

6hr

Atmospheric Model

GFS (2007)

T382 64 levels

GDAS

GSI

24hr

6hr

Land Model

Ice Mdl SIS

LDAS

Ice Ext

Ocean Model

MOMv4

fully global

1/2ox1/2o (1/4o in tropics)

40 levels

6hr

GODAS

3DVAR

CFSRR at NCEP

Climate Forecast System


National report noaa ncep

GODAS access – CPC site

  • Pentad and Monthly data products

  • 1979-present

  • Access to current and archived Monthly Ocean Briefings

http://www.cpc.ncep.noaa.gov/products/GODAS/


National report noaa ncep

GODAS access - NOMADS

  • Pentad and Monthly data

  • Interactive plotting

  • ftp, http – full data file download

  • ftp2u – partial data download

  • DODS

http://cfs.ncep.noaa.gov/ncep_data/


Hycom gfs

HYCOM - GFS

  • Looking into coupling HYCOM to GFS for weather – climate strategy:

    • Lower horizontal resolution, but high vertical resolution to be able to describe interaction physics.

    • ESMF – NEMS based, focus on coupling.

      • Initialization initially by CFS / GODAS.

      • Tentatively upscaling of hi-res global.

    • Utilizing ensembles to design assimilation systems.

    • Lowest priority for us given limited resources.


National report noaa ncep

SST

  • Daily Real-time global SST (RTG_SST_HR) analysis

    • (1/12º latitude, longitude resolution) is generated every 24h (22:30 UTC) using latest 24 h of real-time data.

    • Focus intended on coastal and inland waters.

  • Daily Real-time global SST (RTG_SST) analysis

    • (1/2º latitude, longitude resolution) is generated every 24h (22:30 UTC) using latest 24 h of real-time data.

  • Validation statistics available on WEB page.

  • Recent issues and changes:

    • Various instrument transitions.

    • Ice edge issues have been removed.

    • Coastal issues related to physical retrievals being addressed.


National report noaa ncep

Coastal biases still an issue

Large polar biases have been removed (2009 Q1)

SST

SST

New polar views available on web site.


Sea ice

sea ice

Northern and Southern Hemisphere daily ice concentration products based on SSMI data, including SSMI based weather filtering of data.

+ AMSR


Sea ice1

sea ice

  • Sea Ice For CFSRR

    • Daily, global 0.5º latitude-longitude

    • 26 October 1978 to present

    • Combines data from

      • Canadian Ice Service (Laurentian Lakes).

      • GLERL (Great Lakes).

      • National Snow and Ice Data Center / GSFC (most of globe) through 1996/12/31.

      • NCEP operational analysis from 1997/01/01 (global)

    • To produce a continuous, consistent, high quality series of sea ice concentrations matching to the present day's operational analysis system.

    • Produced 2007, refined 2008, 2009.


Sea ice2

sea ice

  • Sea Ice in RTOFS / HYCOM :

    • Work starts on low-resolution global model (ESMF).

    • Partially motivated by sea ice forecast issues in CFS.

    • Coupled and stand-alone versions:

      • Stand alone useful considering resource ratio HYCOM – ice.

      • Stand-alone to be used for assessing flux errors in GFS.

    • Dynamic-thermodynamic ice with multiple thickness classes.

    • Using operational concentration analyses.


Sst and sea ice

SST and sea ice

  • SST and sea ice are “stand alone” products

    • Will remain so and will be maintained and developed for the foreseeable future:

      • Input for weather models.

      • Independent validation products.

    • Additional products will become available from modeling:

      • SST directly from HyCOM.

      • Ice model embedded in global HyCOM.

    • Data products can benefit from, or be merged with models:

      • SST to follow model trends rather than revert to climatology for areas with prolonged absence of observation data.


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