DMSP F19 SSMIS Cal/Val Progress and NAVGEM Assimilation Results

Tanya Maurer1, Steve Swadley1, Gene Poe2

Ben Ruston1, Anna Booton3, Al Uliana2, Philip Shen2

1NRL, Monterey, CA2SAIC, Monterey, CA

3UK Met Office, Exeter, UK

13th JCSDA Technical Review & Science Workshop College Park, Maryland

May 2015

Outline

• Background• F19 SSMIS Cal/Val status• F19 Cold Bias anomaly detection and mitigation strategy• F19 SSMIS assimilation in NAVGEM

• UPP updates and additions• SSMIS Upper Air Sounding (UAS) capabilities• SSMIS UPP radiance assimilation impacts

• Summary and Look Ahead

• Defense Meteorological Satellite Program (DMSP) heritage: 7 SSM/I, 4 SSMIS• Comprehensive Cal/Val program verify end-to-end instrument performance

DMSP & the SSMIS Cal/Val Program

Current DMSP MW Imager/Sounder Constellation Status

LTAN: Local Time of the Ascending NodeDMSP F19 Launched April 3, 2014

SSMIS deployed April 7, 2014

• Anomaly & systematic bias detection• SDR & EDR validation• Algorithm improvements• Rapid transition of data & products to users

• Early Orbit evaluation• NEDT analysis • Geolocation analysis• Scan uniformity analysis

SSMISSpecial Sensor Microwave Imager/Sounder (SSMIS)• 24 channels, 6 feed horns• Conical Scan Geometry (53° EIA) • Scan Period = 1.89 s (31.6 RPM)• Constant Resolution Across Swath• Scene integration period = 4.219 msec

Channels Frequency (GHz)

Resolution (Km)

Imaging 12-16 19-37 25

Humidity 8-11, 17-18

91-183 12.5

LAS 1-7, 24 50-60 37.5

UAS 19-23 60-63 75

SSMIS Nominal Channel Characteristics

Ch. No.

Center Frequency

[GHz]

1st IF [MHz]

2nd IF [MHz]

BandWidth[MHz]

Pol Peak[hPa]

Legacy Sensor

1 50.3 0. 0. 400. H 1000

AMSU-ASSMT-1

2 52.8 0. 0. 400. H 7003 53.596 0. 0. 400. H 4004 54.40 0. 0. 400. H 2005 55.50 0. 0. 400. H 1006 57.29 0. 0. 350. CP 607 59.4 0. 0. 250. CP 308 150.0 1250. 0. 1500. H AMSU-B

MHSSSMT-2

9 183.31 6600. 0. 1500. H 10 183.31 3000. 0. 1000. H 11 183.31 1000. 0. 400. H 12 19.35 0. 0. 400. H

SSM/I

13 19.35 0. 0. 400. V 14 22.235 0. 0. 500. V 15 37.0 0. 0. 1500. H 16 37.0 0. 0. 1500. V 17 91.655 900. 0. 1500. V 18 91.655 900. 0. 1500. H 19 63.283248 ±285.271 0. 1.5 CP 0.02

NEW20 60.792668 ±357.892 0. 1.5 CP 0.0521 60.792668 ±357.892 ±2. 1.5 CP 0.722 60.792668 ±357.892 ±5.5 3.0 CP 223 60.792668 ±357.892 ±16. 8.0 CP 7 AMSU-A24 60.792668 ±357.892 ±50. 30.0 CP 15

y

DMSP SSMIS Radiometric Performance Status

NAVGEM 1.2.x Operational Assimilation NAVGEM 1.3 Transition

Requires Higher Model Top

SSMIS Warm Load NEDTs(NEDT = Noise Equivalent Delta Temperature)

F19 SSMIS Cal/Val Progress

Geolocation • Earth location errors ~20-30 km observed• Correction factors derived in terms of along-scan & along-track

partial derivatives• Errors are reduced to 3-5 km (spec=7km)

Environmental Data Records (EDR) Validation• OSWS and TPW EDRs validated against ocean buoys and Raob

stations• New APC coefficients derived • Retrieval skill within specification

Spec = 2m/s

F19 SSMIS Cal/Val Progress

Initial NRL RTM Departures Analysis uncovered a Large Cold Bias in the G-band channels. The OB-BK patterns for the 183 GHz channels were similar to F18, but colder by ~8-10K. Only the high frequency G-band channels were affected. Initial focus was on Reflector Roughness, then moved to possibility of FOD in optics via the damaged feedhorn cover.

G-Band Cold Bias Investigation

F19 SSMIS Cal/Val ProgressG-Band Cold Bias Mitigation

• Histograms Plots of the Observed and Background computed TBs for F19 SSMIS Revs 64-66, 2014040806. Biased histograms are shifted and it was shown that altering the SPOFs would mitigate the cold bias.

• New SPOFs, αn, derived using ECMWF Analyses and RTTOV-10 computed TBK

• Computed Ocean Only Scene SPOFs are very stable over time.

Original SPOF = 0.9934

F19 Ch. 11 OB and BK Histograms

Adjusted SPOF = 0.9587

= An

BK

T

T

*SPOF = Spillover Factor

F19 SSMIS Cal/Val ProgressG-Band Cold Bias Mitigation

• Method validated through vicarious calibration with F18

• Shows good performance across all surface types for 6 month period

• SPOF modification justified using APC physical model

• Vicarious Calibration SPOFs match those derived by the NWP RTTOV methodology (within ~0.5-1%)

Long Term Averages over Homogenous Surfaces

• Forecast Model: Navy Global Environmental Model (NAVGEM)– T359L50– 0.04 hPa model top (~70 km)– ~ 37 km horizontal resolution – Semi-Lagrangian/Semi-Implicit dynamical core, forecast model, explicit

clouds

• DA system: NRL Atmospheric Variational Data Assimilation System – Accelerated Representer (NAVDAS-AR)– T359 outer loop, T119 (~ 111 km) inner loop resolution– Radiance bias correction using variational bias correction approach

DMSP F19 SSMIS Data Assimilation

2.6 million obs assimilated every 6 hrs

MW radiances provide significant impact to NWP

NAVGEM/NAVDAS-AR Operational Data

LEO RadiancesImagers/Sounders

DMSP F16 SSMIS Imager DMSP F17 SSMIS LAS, UAS, Imager DMSP F18 SSMIS LAS, UAS, Imager DMSP F19 SSMIS LAS, UAS, Imager METOP-A AMSU-A, IASI, MHSMETOP-B AMSU-A, IASI, MHSNASA EOS Aqua AIRS, AMSU-ANOAA 15 AMSU-ANOAA 16 AMSU-ANOAA 18 AMSU-A, MHSNOAA 19 AMSU-A, MHSJPSS SNPP ATMS, CrIS, VIIRSGCOM-W1 AMSR-2Megha-Tropiques MADRAS, SAPHIRMSG SeveriMSG-II HIRJason-1 (SSH, SWH)Jason-2 (SSH, SWH)Cryosat2 (SSH, SWH)GPM GMIAquarius (Salinity)

FY-3A,B,C,D,E,F MWTS,MWHS,MAIRS MERSIFY-RM 1,2Meteor 3M MTVZA

Satellite WindsLEO and GEO Derived

Coriolis WindSat Ocean Wind VectorDMSP F16 SSMIS Ocean Wind speedDMSP F17 SSMIS Ocean Wind speedDMSP F18 SSMIS Ocean Wind speedDMSP F19 SSMIS Ocean Wind speedMETOP-A AVHRR, ASCATMETOP-B AVHRR, ASCATNASA EOS Aqua MODISNASA EOS Terra MODIS, MISRNOAA NPP VIIRS

Meteosat 9Meteosat 10MTSATNOAA GOES ENOAA GOES WNOAA GOES-RKMA COMS

FY-2E,F,G,H (Geo Winds)FY-4A,B,C (Geo Winds)FY-4A,B,C IR Spectrometer, MW??

GNSS Radio Occultation

C/NOFS CORISSCOSMIC FM1-6GRACE-AMetOp-A GRASMetOp-B GRASSAC-CTerraSAR-XTanDEM-X COMS

Other Satellite ProductsNASA EOS Aura MLS, HRDLS, OMINASA TIMED SABERNOAA SBUVJPSS NPP OMPSSMOSSMAPFY-3A,B,C,D,E,F TOU

Coriolis WindSat TPWDMSP F16 SSMIS TPWDMSP F17 SSMIS TPWDMSP F18 SSMIS TPWDMSP F19 SSMIS TPW

Operational Research Planned Restricted Use

Current Operational MW Sensors

AMSU-A SSMIS ATMS

NAVGEM T359L50

SSMIS Channels assimilated: 2-7, 9-11, 22-24

• Joint development by NRL and UK Met Office• Produces calibrated SSMIS TDR files suitable for radiance assimilation• SSMIS UPP V2 Operational at FNMOC (F16 - 07/2008, F17 - 04/2009, F18 - 04/2010,

F19 – 10/2014)• FNMOC distributes UPP data to NESDIS for use by the global NWP Community• Produces ASCII and BUFR TDR output files at full and/or filtered resolution• UPP V2 run at FNMOC includes:

• Reflector Emission Corrections (F16 and F17)• NRL-derived SPOF factors for cold-bias mitigation (F19)• Operational NGES Fourier Filtered Gain Files to Correct Gain Anomalies • Spatial Averaging to reduce NEΔT to 0.15 - 0.25 K level (NRL only)• Sensor-specific scan Non-uniformity and Geo-location corrections (corrects for

FOV intrusions and spacecraft misalignment)

SSMIS Radiance Assimilation by NAVDAS-AR

SSMIS Unified Pre-Processor (UPP)

• F19 UPP data Operational at FNMOC on 14 October 2014• Utilizes NRL SPOF correction methodology for Cold Bias mitigation• NRL Assimilating F19 channels 2-7, 9-11, 22-24 averaged at σ=37km

• Implemented Orbit Angle, φ, calculation for Bias Correction Predictor• Testing new orbital bias correction scheme using a Fourier Series in ϕ • Developed with Anna Booton (Met Office) during visit (Nov-Dec ‘14)• Using reference relative to the position of the sun results in a more stable predictor

Ecliptic plane

Ascending node φ – angle along the

orbital plane

β – bias coefficientP – bias predictorϕ – orbital angle

SSMIS UPP Updates and Additions

Assimilation of SSMIS by NAVDAS-AR

SSMIS UAS UPP Ready for Operations

High-peaking SSMIS Upper Atmosphere Sounding (UAS) channels: 19, 20, 21• Affected by Zeeman splitting of the oxygen absorption lines at alt > 50 km, due to

interaction of Earth’s magnetic field and SSMIS bore-sight angle• Require separate UAS UPP (operates on channels 19-24) • Retrievals provide key information about upper atmosphere

• Includes parameters: mean Bmag, B-dot-k, θB , and std_dev(B-dot-k) within averaging domain (100 closest UAS scenes)

• Gaussian spatial averaging with σ=75km• Orbit Angle, φ, calculation for Bias Correction

Predictor• Special Met Office file also available at full

resolution

UAS UPP includes:• Calculation of the SSMIS Propagation Vector, k, as the vector difference between the

spacecraft and the UAS scene position vectors• Extraction of the Geomagnetic field vector, B, components at 60 km

* Assimilation of SSMIS UAS channels into NAVGEM is currently limited to CH 21 due to model top

Assimilation of SSMIS by NAVDAS-AR

SSMIS Radiance Data QC/Prep• UPP averaging/thinning:

• Along-scan Gaussian averaging• Every 3rd scan, every other LAS scene (30 scenes per scan)• Every 6th scan, every other UAS scene (15 scenes per scan)

• Pre-assimilation thinning: 1.25°• Quality Control

• Ocean-only scenes for humidity sounding channels (F18, F19)• For temperature sounding channels 02, 03, 04, scenes are

rejected if:• Surface is not 100% homogenous• 20 FOVs in the spatial averaging domain have rain flag set

to “true”• Jacobian w.r.t. surface temperature exceeds threshold

Standard deviations of the bias-corrected innovations (bars) shown on top of weighting functions for each channel.

Operational Assimilation ResultsTemperature Sounding Channels

3 SSMIS UPP (F17,F18,F19)+ 4 SSMIS TPW (F16,F17,F18,F19)+ 4 SSMIS OSWS (F16,F17,F18,F19) 13.6% of Total Error Reduction

2 IASI3 SSMIS UPP6 AMSU-A3 MHS1 AQUA/AIRS5 GEOs1 WindSat12 GNSS/GPS

Forecast Sensitivity Observation Impact (FSOI)

SSMIS F17, F18, F19 UPP Radiances Continue to be the

Highest Performing MW Radiances in Total Error Reduction in NAVGEM

2.81

3.41

2.23

0.98

0.96

0.83

0.51

1.99

2.92

2.50

4.33

5.48

1.47

1.21

1.50

1.91

2.42

x 10-6

Forecast Sensitivity Observation Impact (FSOI) Per ObImpact

Operational Assimilation Results

FSOI by channel: F17, F18, F19

Summary and Look Ahead

• 8-10 K cold bias detected in 183 GHz channels mitigated through modified SPOF in the UPP software

• Calibrated TDR and UPP data transitioned to operations (10/14)

• SDRs and Ocean EDRs transitioned to operations (2/15)• Implemented Orbital Angle, ϕ, for Bias Correction

Predictor in UPP• Ready to Transition UPP and UAS-UPP with Orbit Angle• Operational performance of F19 SSMIS UPP radiances

consistent with suite of high-impact DMSP MW sensors• DMSP F20, last of 5 SSMIS sensors, set to launch 2016

Thank you

24

Antenna Physical Model

𝑇 𝐴𝐹 19=𝛼𝐹 19𝑇 𝑠+ (1−𝛼  𝐹 19 )𝑇𝐶 ≈𝛼𝐹19𝑇 𝑠

To first order APC for G-band, 183 GHz channels (8-11):

1. Feedhorn spill-over loss due to incomplete electromagnetic coupling of feedhorn with reflector

2. Cross-coupling of vertical and horizontal polarizations due to offset parabolic reflector and imperfect feedhorn

3. Field of view intrusion in earth scene sector by spacecraft and/or calibration targets

where TA = Antenna temperature (TDR)TS = Scene brightness temperatureTC = Cosmic background temperaturea = spill-over factor (SPOF)

Antenna Pattern Correction (APC) necessary for all SSMIS instruments

25

𝑇 𝐴𝐹 19=𝑎𝑇 𝐴𝐹 18

Relate TAF19 to TAF18 on the basis of wide range of TDR “averages”

Approach

• Select diverse regions of the globe with approximate spatial uniformity and relatively small terrain variations

• Define averages over central portion of swath, separately for both ascending and descending orbits

• Employ same time period for F19 and F18: April – Sept, 2014 (due to loss of F18 Ch 8, use April – Sept, 2011)

• From physical model relationship, F19 and F18 TDRs may be defined in terms of a constant slope, a

26

• Select “a” using: Minimum Mean Square Estimator with Regression through the Origin

Approach

�̂� (𝑥 𝑖 )=𝑎𝑥 𝑖

𝜀2 (𝑎 )= 1𝑁 ∑

𝑖=1

𝑁

[ �̂� (𝑥𝑖 )− 𝑦 𝑖 ]2

is minimized when a is selected to be:

𝑎=∑𝑖=1

𝑁

𝑥 𝑖 𝑦 𝑖

∑𝑖=1

𝑁

𝑥𝑖2

𝛼𝐹 19=𝑎𝛼𝐹18

• Knowledge of a implies

90% of 10.8 Million total data points assimilated into DoD’s global

environmental model (NAVGEM) in a 24 hr period come from satellites

74% of these satellite data points are provided by MW/IR Sounders

Satellites from Multiple Agencies,

Platforms and Orbit Planes Feed Data to

the DoD Models

Current NAVGEM:37km Resolution50 Vertical Levels

IA CompliantClass/Unclass Domains

MW and IR Sounders in Multiple Orbit Planes Provide the Majority of the Data Necessary to Drive DoD’s Global Weather Prediction Model

NAVGEM ProvidesLateral Boundary Conditions for High Resolution Models: COAMPS and COAMPS-TC

Class/Unclass Domains

NAVGEM Operational Real-time Data Counts10.8 Million Total OBs per Day Assimilated

DTG: 2014121700

Ob Type Sensor OB Count/Day % Total OB Impact %

Satellite All 9.82x 106 90.88 59.3

HyperSpec IR IASI(2), AIRS 4.80x 106 44.44 16.5

MW Sounder AMSUA(6), ATMS SSMIS(3),

MHS(2)GPS-RO

3.19x 106 29.56 22.8

Feature Tracked Winds

GOES(3), Polar(3),

MeteoSat(2), GMS, LeoGeo,

1.70x 106 15.77 23.5

OSWV ASCAT(2), WindSat

0.0640x 106 0.59 2.2

MW ImagerOSWS, TPW

SSMIS, WindSat(TPW)

0.0720x 106 0.67 4.0

Upper Atmosphere Sounding Capability Post F20 SSMIS

• SSMIS - ONLY Operational Satellite with Mesospheric Soundings

• Most Operational NWP Centers pushing upper model levels to ~100 km

• NRL-DC/MRY have devoted significant resources in developing Upper Atmosphere NWP capability

• Operational use of 3 highest peaking channels just now coming into use