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Data Impact Experimentsat the JCSDA and NCEP/EMC

S. Lord (NCEP/EMC)L.P. Riishojgaard (JCSDA)

Contributions by:L. Cucurull, J. Jung, L. Bi, D. Kleist, B. Yan, I.

Appel, D. Stokes

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Overview

• Impact experiments for:– COSMIC– QuikSCAT & Windsat– MODIS winds– IASI– SSM/IS– ASCAT

• Summary and comments

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COSMIC Data Impact

• No COSMIC• With COSMIC• 1 Nov 2006 to 30 Nov 2006• Refractivity assimilated variable• ~1000 profiles assimilated per day

Tropics 200 hPa RMS Wind Error 48 h

NH 500 hPa Height Anom. Cor. SH 500 hPa Height Anom. Cor.

0.1 m/s improvement

L. Cucurull

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QuikSCAT Impact on Standard Verification Scores

• Operational GFS (T382/L64), GSI with FOTO– Control (operational QuikSCAT)– Q denial (no QuikSCAT)– Q new (FY07 improved retrievals)

• 5 July 2005 25 to October 2005 (~4 months)NH 1000 hPa Height RMS Error SH 1000 hPa Height RMS Error

Similar results obtained for 2006 cases

D. Kleist

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Windsat Impact on Standard Verification Scores

• Operational GFS (T382/L64), GSI with FOTO– Control (operational QuikSCAT)– Ws included (with QuikSCAT)– Ws only (no QuikSCAT)– No Ws, no Qs

• 25 April 2007 to 8 June 2007 (~1.5 months)SH 1000 hPa Height RMS ErrorNH 1000 hPa Height RMS Error

D. Kleist

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QuikSCAT Impact on Tropical Cyclone Forecasts

2004 Study

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

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Jung and Zapotocny

JCSDA

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QuikSCAT Impact on Tropical Cyclone Forecasts (cont)

Climatology-persistenceNo QuikSCAT

New QuikSCAT

Track Error Atlantic 2005 00&12 UTC Track Error Atlantic 2005 00&12 UTC

65 cases 18 casesD. KleistD. Stokes

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Impact of MODIS winds on GFS500 hPa Anomaly Correlation

Southern Hemisphere, February 2007

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Southern Hemisphere, July 2007

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I. Appel

NH February

SH February

NH July

SH July

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IASI Impact Tests

• First attempt to use data at JCSDA/NCEP(EMC)

• Channel selection: EUMETSAT longwave only

• 30 day spinup for bias correction• Experiment and control use same initial

bias corrections • Scores averaged over last 30 days

– 1-31 August 2007– 16 December 2007 -15 January 2008

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IASI Impact on Standard Verification Scores

N. Hemisphere 500 hPa AC Z 20N - 80N Waves 1-20

1 Aug - 31 Aug 2007

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Control IASI_EUMETSAT

S. Hemisphere 500 hPa AC Z 20S - 80S Waves 1-20

1 Aug - 31 Aug 2007

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Control IASI_EUMETSAT

NH 500 hPa Height Anom. Cor.

1-31 August 2007

SH 500 hPa Height Anom. Cor.

J. Jung

IASIControl

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IASI Impact on Standard Verification Scores

N. Hemisphere 500 hPa AC Z 20N - 80N Waves 1-20

16 Dec 2007 - 15 Jan 2008

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Control IASI_EUMETSAT

NH 500 hPa Height Anom. Cor.

16 December 2007 - 15 December 2008

SH 500 hPa Height Anom. Cor.

S. Hemisphere 1000 hPa AC Z 20S - 80S Waves 1-20

16 Dec 2007- 15 Jan 2008

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Control IASI_EUMETSAT

J. Jung

IASIControl

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SSM/IS Impact Summary Positive impacts of SSMIS UPP data can be obtained

through improved cloud detection, surface snow and sea ice emissivity simulations

A positive impact of SSMIS UPP data is anticipated by adding water vapor channels (not shown)

The SSMIS UPP data displays some regionally dependent biases at several sounding channels which would reduce their assimilation impact (not shown)

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Improved snow and sea ice emissivity

Improved SSM/IS forecast impact due to science & processing upgrades

Improved cloud detection & QC

CTLEXP

Cloud detection & QCEXP

CTL

Alternateprocessing

B. Yan et al

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ASCAT Impact Tests

S. Hemisphere 1000 hPa AC Z 20S - 80S Waves 1-20

10 Dec 2007 - 19 Jan 2008

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Control ASCAT

• First results at JCSDA/NCEP(EMC)• 10 December 2007 – 19 January 2008• Thinned to 100 km• Quality Control:

– Ocean only (from GDAS land-sea flag)– Reject observation if O-B > 5m/s (U and V)

Li Bi &J. Jung

H. Hemisphere 1000 hPa AC Z20N - 80N Waves 1-20

10 Dec 2007 - 19 Jan 2008

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ASCATControl

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S. Hemisphere 1000 hPa AC Z 20S - 80S Waves 1-20 10 July - 17 Aug 2007

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ASCAT Impact Tests

H. Hemisphere 1000 hPa AC Z20N - 80N Waves 1-2010 July - 17 Aug 2007

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Control ASCAT

• First results at JCSDA/NCEP(EMC)• 10 July 2007 – 17 August 200• Thinned to 100 km• Quality Control:

– Ocean only (from GDAS land-sea flag)– Reject observation if O-B > 5m/s (U and V)

Li Bi &J. Jung

NH 1000 hPa Height Anom. Cor. SH 1000 hPa Height Anom. Cor.

ASCATControl

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Summary & Comments• Impacts measures by standard scores for

– COSMIC– QuikSCAT & Windsat– MODIS winds– IASI– SSM/IS– ASCAT

• JCSDA and NCEP experience– Spin up of global system takes ~6 weeks to produce reliable obs. sensitivity

signal– Coarse resolution results not representative of those at resolutions higher

than ~50 km globally– Use of downstream models and applications could be useful to determine

impacts• Hurricanes• Waves

• Impact depends on improvements to science (e.g. SSM/IS)– Surface emissivity (MW and IR)– Bias correction– Cloud detection

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Summary & Comments(cont)

• Impact experiments are resource intensive– Many take place in the course of the operational

implementation process and are necessary– Many custom experiments generally beyond our means

• Respond to HQ requests for special programs (e.g. QuikSCAT)

– Could (and should) be done annually with proper support (e.g. instrument programs)

• Would pay dividends in – Focusing scientific development– Providing feedback for future instrument programs– Keeping entire community engaged in the total investment

• A complementary OSSE program would be a very useful addition

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Backup Slides

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SATELLITE DATA STATUS – May 2008Jason Altimeter Implemented into NCEP GODAS

AIRS with All Fields of View Implemented – 1 May

MODIS Winds Implemented– 1 May

NOAA-18 AMSU-A Implemented– 1 May

NOAA-18 MHS Implemented– 1 May

NOAA-17 SBUV Total Ozone 4 December 2007

NOAA-17 SBUV Ozone Profile Implemented– ???

SSMI/S Radiances Preliminary forecast assessment completed

GOES 1x1 sounder radiances Implemented 29 May 2007

METOP AMSU-A, MHS, HIRS Implemented 29 May 2007

COSMIC/CHAMP Implemented (COSMIC – 1 May) CHAMP Data in prep.

MODIS Winds v2. Test and Development

WINDSAT Preliminary forecast assessment completed

AMSR/E Radiances Preliminary forecast assessment completed

AIRS/MODIS Sounding Channels Assim. Data in Preparation

JMA high resolution winds Implemented 4 December 2007

GOES Hourly Winds, SW Winds To be Tested

GOES 11 and 12 Clear Sky Rad. Assim(6.7µm) To be Tested

MTSAT 1R Wind Assim. Data in Preparation

AURA OMI Test and Development

TOPEX,ERS-2 ENVISAT ALTIMETER Test and Development (Envisat) ERS-2 (dead) TOPEX implemented in NCEP GODAS

FY – 2C Data in Preparation

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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)

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NOHIRS

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NOQuikscat

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

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Operational data assimilation at NCEP

Lidia Cucurull

Joint Center for Satellite Data Assimilation

COSMIC IWG Meeting, New Orleans, LA, Jan 21 2008.

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• The JCSDA developed, tested and incorporated into the new generation of NCEP’s Global Data Assimilation System the necessary components to assimilate two different type of GPS RO observations (refractivity and bending angle). These components include:– complex forward models to simulate the observations (refractivity and bending angles) from

analysis variables and associated tangent linear and adjoint models – Quality control algorithms & error characterization models– Data handling and decoding procedures– Verification and impact evaluation algorithms

• Pre-operational implementation runs showed a positive impact in model skill when COSMIC profiles were assimilated on top of the conventional/satellite observations.

• As a result, COSMIC became operationally assimilated at NCEP on May 1st 2007, along with the implementation of the new NCEP’s Global Data Assimilation System (GSI/GFS). [Profiles of refractivity were selected for implementation in operations, while the tuning of the assimilation of bending angles is currently being analyzed at NCEP].

• The assimilation of observations from the COSMIC mission into the NCEP’s operational system has been a significant achievement of the JCSDA. [Operational assimilation one year after launch!].

Achievements at the JCSDA

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Characteristics of COSMIC observations

• Limb sounding geometry complementary to ground and space nadir viewing instruments– High vertical resolution (0.1 km surface - 1km tropopause)– Lower horizontal resolution (~300 km)

• All weather-minimally affected by aerosols, clouds or precipitation

• High accuracy (equivalent to < 1 Kelvin from 5-25 km)• Equivalent accuracy over ocean than over land• Independent of radiosonde calibration• No instrument drift• Global coverage• No satellite-to-satellite observational bias• Inexpensive compared to other sensors

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Characteristics of COSMIC observations

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profiles received at NCEP in time for operations

OctoberNovember December

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obs assimilated (%)

OctoberNovemberDecember

Average COSMIC counts/day at NCEP (2007)

• We assimilate rising and setting occultations, there is no black-listing of the low-level observations (provided they pass the quality control checks), and we do not assimilate observations above 30 km (due to model limitations).

• In an occultation, the drift of the tangent point is considered.

The remaining ~30% received, but not assimilated, is due to:– Preliminary quality control checks (bad data/format)– Gross error check (obs very different from the model)– Statistics quality control check (obs too different from the model-obs statistics)

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Pre-operational implementation run

• PRYnc (assimilation of operational obs ),

• PRYc (PRYnc + COSMIC refractivity)

• We assimilated around 1,000 COSMIC profiles per day

Anomaly correlation as a function of forecast day (geopotential height)

rms error(wind)

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•Dashed lines: PRYnc•Solid lines: PRYc (with COSMIC)

•Red: 6-hour forecast•Black: analysis

Pre-operational implementation run (cont)

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Summary and future plans • COSMIC (refractivity) became operationally assimilated at NCEP on

May 1st 2007, along with the implementation of the new NCEP’s Global Data Assimilation System (GSI/GFS).

• Several impact studies for selected periods show a positive impact in model skill when COSMIC profiles are assimilated on top of the conventional/satellite observations. [We have recently improved the assimilation of GPSRO profiles over complex topography.]

what is next?• Testing, tuning and assimilation of GSPRO from CHAMP & GRACE (in

pre-operational mode; March 2008) and MetOp/A GRAS (when available).• Setup the monitoring of GPSRO statistics in operations (May 2008).• Update QC checks and obs error for COSMIC data (June 2008).• Assimilation of COSMIC observations (and other GPSRO missions) into

the regional model (July 2008).• Improve the performance of the assimilation of observations of bending

angle (November 2008; switch to bending angle in operations?).• Explore more complex forward operators to take into account horizontal

gradients of refractivity (??).

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Time series of day-5 scoresNorthern Hemisphere, July 2007

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Five-day forecast minus verifying analysis. February 23, 2007, 00z

Control Control + MODIS IR

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Impact of Improved Snow and Sea Ice Emissivity at SSMIS Channels on F16 UPP SSMIS Data Usage

NewSNOWEM

NewIce EM

Old EM

More data is assimilatedInto GFS !

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A positive impact of SSMISUPP data at water vapor sounding channels is detected on GFS.

(July 1 ~ July 10, 2007)