Global Impact of Satellite Data on NWP
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Global Impact of Satellite Data on NWP. Model is GFS. Satellite data include HIRS, AMSU, Quickscat, and all geo winds. Courtesy of Tom Zapotocny. Current Users :

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Global impact of satellite data on nwp

Global Impact of Satellite Data on NWP

Model is GFS. Satellite data include HIRS, AMSU, Quickscat, and all geo winds.

Courtesy of Tom Zapotocny


Global impact of satellite data on nwp

  • Current Users:

  • European Centre for Medium-Range Weather Forecasts (ECMWF; Lueder von Bremen and Jean-Noel Thepaut) - Using winds in operational system.

  • NASA Global Modeling and Assimilation Office (GMAO; Lars Peter Riishojgaard and Yanqiu Zhu) - Using winds in operational system.

  • Japan Meteorological Agency (JMA; Masahiro Kazumori) – Using winds in operational system (Arctic only)

  • Canadian Meteorological Centre (CMC; Real Sarrazin) – Using winds in operational system.

  • US Navy, Fleet Numerical Meteorology and Oceanography Center (FNMOC; Pat Pauley and Chuck Skupniewicz) – Using winds in operational system.

  • UK Met Office (Mary Forsythe and Howard Berger) – Using winds in operational system.

  • National Centers for Environmental Prediction NCEP/EMC; John LeMarshall, Jim Jung, Tom Zapotocny) - Engaged in impact studies. Plan to go operational in June 2005.

  • Deutscher Wetterdienst (DWD; Alexander Cress) – Using winds in experimental system

  • NCAR Antarctic Mesoscale Model (AMPS; Dale Barker) – Beginning to test the winds over Antarctica.

  • Other (incomplete information): Chinese meteorological agency, one or more countries involved in HIRLAM.

  • Potential Users:

  • Forecast offices: NWS Alaska (Gary Hufford); McMurdo – Not using them yet, but will.

  • ECMWF Reanalysis (Fedor Mesinger) – Would also use historical AVHRR winds if available.

MODIS Winds in NWP


Nasa global modeling and assimilation office gmao lars peter riishojgaard and yanqiu zhu

NASA Global Modeling and Assimilation Office (GMAO)(Lars Peter Riishojgaard and Yanqiu Zhu)

  • MOWSAP (MODIS Winds Special Acquisition Period): November 8, 2003-January 31, 2004

    • Winds generated by CIMSS and by NESDIS (pre-operational mode)

      • Different code bases

      • Different backgrounds for QC and height assignment

    • Winds generated from MODIS Aqua and MODIS Terra imagery

    • Assimilation experiments by GMAO, ECMWF, Met Office, CMC

    • Standard common diagnostics

    • GMAO experiments: 5-day forecast every other day; 42 members in the ensemble


Global impact of satellite data on nwp

Frequency of Water Vapor and IR Winds


Forecast skills verified against their own analyses

Forecast skills verified against their own analyses

(CIMSS winds)

(NESDIS winds)

Forecast scores are the correlation between the forecast geopotential height anomalies, with and without the MODIS winds, and their own analyses.


Forecast skills verified against ncep analysis

Forecast skills verified against NCEP analysis

(CIMSS winds)

(NESDIS winds)


Forecast skills verified against ncep analysis1

Forecast skills verified against NCEP analysis

(CIMSS winds)

(NESDIS winds)


Global impact of satellite data on nwp

Forecast Busts (GMAO)

Southern Hemisphere Extratropics

Arctic

Blue is forecast with MODIS winds; red is control run


Global impact of satellite data on nwp

Propagation of Error (animation)


Summary of gmao results

Summary of GMAO Results

  • MODIS winds complement other observations in the high latitudes; more so in the SH than in the NH due to the current data sparsity

  • Consistency of data delivery is acceptable; timeliness remains problematic; being addressed using DB capability

  • Based on independent verification and innovation statistics, the quality of the information is acceptable

  • Positive overall contribution to forecast skill; substantial in the SH


Global impact of satellite data on nwp

European Centre for Medium-Range

Weather Forecasts (ECMWF)

(Lueder von Bremen and Jean-Noel Thepaut)

Assimilation experiments

- 3DVAR, T159/159: 5 March—3 April 2001

- 4DVAR, T511/159, compared to ops: 13 July—16 August 2002…

- 4DVAR, T511/159: 5—15 March 2002…

Use same assimilation settings as for geostationary AMVs, except for blacklisting of lower level winds:

Winds used:

IR, WV cloudy and clear

Over land: IR and WV winds above 400 hPa.

Over sea: IR winds above 700 hPa, WV above 550 hPa.


Global impact of satellite data on nwp

ECMWF Mean and Difference Wind Fields:

700 hPa


Global impact of satellite data on nwp

ECMWF Mean and Difference Wind Fields:

400 hPa

Arctic: MODIS winds act to strengthen the circulation at upper levels; at lower levels the difference field suggests a weakening of the local circulation.

Antarctic: MODIS winds act to strengthen the flow around the Antarctic Peninsula.


Global impact of satellite data on nwp

Forecast Impact (3DVAR)

Anomaly correlation for 500 hPa geopotential, each experiment verified against its own analysis. Forecast scores are the correlation between the forecast geopotential height anomalies, with and without the MODIS winds, and their own analyses.

Northern Hemisphere

Arctic (N of 65N)


Global impact of satellite data on nwp

Forecast Impact (3DVAR, cnt’d)

Anomaly correlation for 500 hPa geopotential, each experiment verified against its own analysis.

Southern Hemisphere

Antarctic (S of 65S)


Global impact of satellite data on nwp

Forecast Impact (4DVAR)

Anomaly correlation for geopotential, each experiment verified against operational analysis.

NH, 1000 hPa

NH, 500 hPa


Global impact of satellite data on nwp

Forecast Impact (4DVAR, cnt’d)

Anomaly correlation for geopotential, each experiment verified against operational analysis.

SH, 1000 hPa

SH, 500 hPa


Global impact of satellite data on nwp

Forecast Impact (4DVAR, cnt’d)

N.POLE

N.ATL

EUROPE

E.ASIA


Global impact of satellite data on nwp

ECMWF: Error Propagation to the Midlatitudes

This animation illustrates the propagation of analysis errors from the poles to the midlatitudes for one case study. Each frame shows the 500 hPa geopotential height for forecasts from 1 to 5 days in 1 day increments. The solid blue line is the geopotential from the experiment that included MODIS winds; the dashed black line is the control (CTL) experiment without MODIS winds. Solid red lines show positive differences in the geopotential height (MODIS minus CTL), and thick dashed green lines show negative differences.

The area of large positive differences near the Beaufort Sea (north of Alaska) moves southward over the 5-day period. The CTL run is forming a deeper trough over central Alaska and then over the Pacific south of Alaska than the MODIS run.

The 5-day MODIS forecast verifies better against the subsequent analysis (not shown), so the initial analysis for this MODIS forecast was closer to the “truth” than the CTL (positive impact on forecast). The propagation of differences is therefore also a propagation of analysis errors in the CTL forecast.

Better observations over the poles should improve forecasts in the midlatitudes.


Global impact of satellite data on nwp

Error Propagation to the Midlatitudes: Snowfall

Accumulated snowfall forecasts (mm water equivalent) over Alaska for 20 March 2001. Inclusion of MODIS winds in the analysis can produce a more accurate forecast. At right is the snowfall from the 5-day Control forecast (no MODIS winds); below left is the snowfall from the 5-day forecast that included the MODIS winds in the analysis; below right is the snowfall from a 12-hr forecast for verification (“truth”).


Global impact of satellite data on nwp

Canadian Climate Centre (CMC)

(Real Sarrazin)

  • Now: - Uniform resolution of 100 km (400 X 200 X 28)

    • - 3D-Var at T108 on model levels, 6-hr cycle, use of raw

    • radiances from AMSUA, AMSUB and GOES

  • 2004: - Resolution to ~35 km (800 X 600 X 56) - 4D-Var assimilation, 6-hr time window with 3 outer loops at full

    • model resolution and inner loops at T108

    • - new datasets: profilers, MODIS winds, AMSUA on AQUA

    • - EnKF for EPS

  • 2005: - Top at 0.1 hPa (instead of 10 hPa) with additional AMSUA and

    • AMSUB channels (Clément`s presentation)

    • - assimilation of AIRS, MSG, MTSAT, QuikScat, SSM/IS

    • - revised 4D-Var statistics

  • 2006-07: - Additional datasets: IASI, GIFTS, COSMIC…

  • - very large increase in volume of assimilated data


  • Global impact of satellite data on nwp

    CMC 3DVAR Impacts

    Nov 5 – Dec 15, 2003

    Slight positive impact in the Arctic, positive in the Antarctic and SH, neutral in NH


    Global impact of satellite data on nwp

    MODIS winds: latest results at the Met OfficeMary Forsythe (1), Howard Berger (1,2)(1) Met Office, Exeter, UK(2)UW-CIMSS Madison, WI


    Distribution of modis winds

    100

    200

    300

    400

    500

    Pressure (hPa)

    600

    700

    800

    900

    1000

    0

    20

    40

    60

    80

    100

    120

    Number of winds

    Thousands

    Distribution of MODIS winds

    NESDIS Feb 04

    Terra NH

    Terra SH

    Aqua NH

    Aqua SH

    100

    200

    300

    400

    500

    Pressure (hPa)

    600

    700

    CSWV

    WV

    CSWV

    IR

    800

    900

    1000

    0

    20

    40

    60

    80

    100

    120

    Number of winds

    Thousands

    • More Terra winds in NH than SH

    • More Aqua winds in SH than NH

    • SH winds (summer) peak at lower pressures


    Some statistical comparisons to meto background

    Some Statistical Comparisons to MetO background

    NESDIS Feb 04

    Comparing Satellites Comparing Channels

    IR

    Terra NH


    Global impact of satellite data on nwp

    Thinning demonstration:


    Global impact of satellite data on nwp

    Thinning demonstration:


    Global impact of satellite data on nwp

    Verification vs OBS and ANAL

    3

    vs OBSERVATIONS

    vs ANALYSES

    2

    1

    % RMS difference (experiment – control)

    0

    -1

    -2

    NH H500 T+72

    NH H500 T+24

    NH H500 T+48

    SH H500 T+72

    NH PMSL T+96

    SH PMSL T+24

    SH PMSL T+48

    SH PMSL T+72

    NH PMSL T+24

    NH PMSL T+48

    SH H500 T+24

    SH H500 T+48

    SH PMSL T+96

    NH W250 T+24

    SH W250 T+24

    NH PMSL T+72

    NH PMSL T+120

    SH PMSL T+120

    Trop W850 T+24

    Trop W850 T+48

    Trop W850 T+72

    Trop W250 T+24


    Global impact of satellite data on nwp

    Conclusions

    • Winds from Aqua and Terra are of comparable quality.

    • Some benefits were observed in the forecasts when CSWV winds were included, blacklisting was modified and the thinning box was increased.

    • The NESDIS MODIS product compares better with MetO background than the CIMSS product.

    • The latest MODIS experiment at the Met Office, using the NESDIS MODIS winds, is the first to give neutral to positive impact in all latitude bands.

    • Direct broadcast should allow more MODIS winds to be used in the Met Office assimilation system.


    Modis polar winds assimilation experiments at jma

    MODIS Polar Winds Assimilation Experiments at JMA

    Masahiro Kazumori, Yoshiyuki Nakamura

    Numerical Prediction Division

    Japan Meteorological Agency


    Impacts on forecast

    Impacts on Forecast

    • Anomaly Correlation and RMSE at 500hPa

      • Large improvement for both seasons in the N.H.

      • Neutral for the Tropics and the S.H.

        (no MODIS assimilation in these regions)

      • Change in the Arctic spread to the lower latitudes.

    • RMS forecast error of wind vectors were reduced.

      • Especially, improvements at 500hPa was remarkable.

        ( 500hPa was the level with maximum data number)

    • Improvements on typhoon track prediction

      • Small, but positive impacts were found at the later stage in the forecasts.


    Z500 anomaly correlation

    Z500AnomalyCorrelation

    Red:TEST

    Blue:CNTL

    Large improvements were found for the Northern Hemisphere.


    Rms forecast error difference for 500hpa z test minus cntl

    RMS forecast error difference for 500hPa Z TEST minus CNTL

    (m)

    (m)

    (m)

    • Monthly mean difference for July 2003

    1day forecast

    3day forecast

    5day forecast

    Positive Impacts of MODIS (negative difference) spread to mid-latitudes with procession of forecast.


    Impacts on forecast1

    Impacts on Forecast

    • Anomaly Correlation and RMSE at 500hPa

      • Large improvement for both seasons by 9-day forecasts

      • Neutral for the tropics and the S.H.

        (no MODIS assimilation)

      • Change in the Arctic spread to the lower latitudes.

    • RMS forecast error of wind vectors were reduced.

      • Especially, improvements at 500hPa were remarkable.

        ( 500hPa was the level with maximum data number)

    • Improvements on typhoon track prediction

      • Small, but positive impacts were found at the later stage in the forecasts.


    Zonal mean of rmse of wind speed at 500hpa 5 day forecasts january2004

    Zonal mean of RMSE of Wind Speed at 500hPa(5-day forecasts,January2004)

    (m/s)

    Improvement

    (m/s)

    Improvement


    Impacts on forecast2

    Impacts on Forecast

    • Anomaly Correlation and RMSE at 500hPa

      • Large improvement for both seasons by 9-day forecasts

      • Neutral for the tropics and the S.H.

        (no MODIS assimilation)

      • Change in the Arctic spread to the lower latitudes.

    • RMS forecast error of wind vectors were reduced.

      • Especially, improvements at 500hPa was remarkable.

        ( 500hPa was the level with maximum data number)

    • Improvements on typhoon track prediction

      • Small, but positive impacts were found at the later stage in the forecasts.


    Mean positional error of typhoon track predictions

    Mean positional error of typhoon track predictions

    • 22 events in July 2003

    • Neutral or slightly positive at the later stage in the forecast time.


    Summary

    Summary

    • The MODIS polar winds assimilation experiments were performed at JMA

      • Period:July 2003, January 2004

      • Used data:Aqua/MODIS,Terra/MODIS in the Arctic

      • QC

        • Over land, above 400hPa for IR and WV

        • Over ocean, above 700hPa for IR and 550hPa for WV

      • Data thinning 150km

    • Results

      • Improvements on the analysis and first guess in the Arctic.

      • Large positive impacts on forecasts for both seasons. ( height, temperature, wind fields)

      • Improvements on the typhoon track prediction.

    JMA started the assimilation of MODIS polar winds in the Arctic operationally at 27 May 2004.


    Global impact of satellite data on nwp

    Usage of MODIS winds

    Usage: over Land and Oceans

    IR above 1000 hPa; over Antartica only above 700 hPa

    Wvcloudy above 700 hPa

    FG check: asymmetric to remove negative OBS-FG bias

    Thinning: 1 wind per pre-defined thinning box (oper.: 70 x 70 km; 15 vertical layers).

    Same observation errors as SATOB

    Experiments:

    CTL: Routine assimilation and forecast system using different kinds of

    observing systems (synops, buoys, aircraft, radiosondes, satob, satem, paob)

    Exp: CTL plus MODIS winds for a summer and an autuum case

    7th Int. Winds Workshop

    Alexander Cress


    Global impact of satellite data on nwp

    Mean analysis diferences between Control + Modis and Control

    7th Int. Winds Workshop

    Alexander Cress


    Global impact of satellite data on nwp

    Anomalie correlation

    date: 2003061200 - 2003070900

    28 forecasts; verified against routine analyses

    SH

    forecast time h

    forecast time h

    7th Int. Winds Workshop

    Alexander Cress


    Global impact of satellite data on nwp

    Anomalie correlation

    date: 2003061212 - 2003070912

    28 forecasts; verified against routine analyses

    forecast time h

    forecast time h

    7th Int. Winds Workshop

    Alexander Cress


    Global impact of satellite data on nwp

    500 hPa Geopotential

    Northern Hemisphere

    VV= +60h

    7th Int. Winds Workshop

    Alexander Cress


    Global impact of satellite data on nwp

    Summary of MODIS wind results

    • Good correspondence between MODIS wind statistics and similar statistics

      for AMV winds from geostationary satellites

    • FG statistics look very similar between Terra and Aqua.

    • Some differences exists in the OBS-FG, OBS-ANA statistics between

      Terra and Aqua over Antartica

    • Large impact on polar analysis by introducing analysis increments in data

      void areas

    • Impact of MODIS winds depends strongly on season and occasions

      in which the interaction between polar and midlatitude flow patterns

      is particularly intense

    7th Int. Winds Workshop

    Alexander Cress


    Modis wind assimilation ncep s global forecast system

    MODIS Wind Assimilation NCEP’s Global Forecast System

    John Le Marshall (JCSDA)

    James Jung (CIMSS)

    John Derber (NCEP)

    Jaime Daniels (NESDIS)

    International Winds Workshop

    June 14, 2004


    Global impact of satellite data on nwp

    Global Forecast System Background

    • Operational SSI (3DVAR) version used

    • Operational GFS T254L64 with reductions in resolution at 84 (T170L42) and 180 (T126L28) hours. 2.5hr cut off


    Global impact of satellite data on nwp

    The Trial

    • Used MOWSAP (MODIS Winds Special Acquisition Period) data

      • NESDIS (Ops.) generated AMVs

      • 1 Jan – 15 Feb ‘04

      • Terra & Aqua satellites

    • Similar assimilation methodology that used for GOES AMVs

    • Middle image used for tracers

    • AMVs largely used NESDIS QC

    • Post NESDIS QC used, particularly for gross errors cf. background and for winds above tropopause

    • Winds assimilated only in second last analysis (later “final” analysis) to simulate realistic data availability.


    Discussion and conclusions

    Discussion and Conclusions

    • Overall positive impact

    • AMV observation fit to background worst over land and ice near the surface. AMVs still have positive impact in lower levels

    • Post NESDIS QC used, particularly for gross errors cf. background and for winds above tropopause

    • Repeat with emissivity corrections for ice and snow in GFC

    • Planned for implementation in next upgrade


    Global impact of satellite data on nwp

    RMS (m/s)

    Forecast (days)

    Impact of MODIS Winds on Hurricane Track Forecasts


    Global impact of satellite data on nwp

    AVERAGE HURRICANE TRACK ERRORS (NM)

    FREQUENCY OF SUPERIOR HURRICANE PERFORMANCE (%)*

    • Percent of cases where the specified run had a more accurate hurricane position than the other run.

    • Note: These cases are for hurricanes in the subtropics.


    Global impact of satellite data on nwp

    Fleet Numerical Meteorology and Oceanography Center (FNMOC)

    (Pat Pauley, Randal Pauley)

    • NAVDAS

    • NRL Atmospheric Variational Data Assimilation System

    • Three-dimensional variational data assimilation system cast in observation space

      • Determines an optimal state of the atmosphere using the error statistics of the observing and forecast systems

      • Directly assimilates observations without conversion to the model state variables

      • Operates on both global and regional model domains

    • Transitioned to operational use at FNMOC on 1 Oct 2003

    • Original implementation included geostationary feature-track winds but not MODIS winds


    Global impact of satellite data on nwp

    • Use of feature-track winds in NAVDAS

    • Winds superobbed in 2 ° “prisms”

    • “Prisms” are nearly square regions

      • 2 ° latitude by 2 ° longitude at equator

      • Width adjusted to keep area nearly constant

      • Integer number of prisms in each latitude band

    • Superobbing subject to several constraints

      • At least two consistent observations

      • One or two outliers may be rejected

      • Wind speeds within 7 m/s

      • u, v components within 5 m/s or directions within 20 °

      • Innovations (ob – background) averaged and used in NAVDAS at the average location

    • Observation error same as for geostationary feature-track winds


    Global impact of satellite data on nwp

    500 mb height anomaly correlation for 00Z forecasts. “NOGAPS” is the control run; “BETA” includes MODIS winds.

    Increased skill at ranges beyond 48 hours in the Arctic (left) and Northern Hemisphere (right)


    Global impact of satellite data on nwp

    500 mb height anomaly correlation for 00Z forecasts. “NOGAPS” is the control run; “BETA” includes MODIS winds.


    Global impact of satellite data on nwp

    • FNMOC Results and plans

    • Early results show MODIS winds have a positive impact in the Northern Hemisphere, but a negative impact in the Southern Hemisphere.

    • More recent testing looks better in the Southern Hemisphere but less positive in the Northern Hemisphere.

    • Began use of MODIS winds in operational forecast system in October 2004.

    • Future items to test include a more stringent QC (e.g., omitting lower quality winds, lower-level Southern Hemisphere winds) and increasing the observation error.


    Global impact of satellite data on nwp

    Recommendation from WMO NWP Workshop held in 9-12 March 2004 in Alpbach, Austria (attended by 52 NWP experts representing more than 20 NWP centers)

    “polar wind observations should be developed further and an operational follow-on to the MODIS winds be secured (this will require a water vapour channel on the operational imagers on NPOESS and METOP). Timeliness of data delivery can be addressed through direct data read-out. The number of stations with direct read-out capability should be increased. Such data should be made available directly to the processing centres.”


    Global impact of satellite data on nwp

    3D display of impact of polar winds on GFS

    84 hr forecast of 400 hPa heights


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