IOVWST 2016

Resolutionenhancement for

ASCAT

Jur VogelzangAd Stoffelen

KNMI

with help from

Richard LindsleyMERS BYU

ASCAT-625Von Karman vortices

Madeira

Introduction ASCAT‐625 heritage

bull ASCAT‐625 will become operational in the next AWDP release (AWDP 24)

bull Downscaling of ASCAT‐coastal product by a factor of 2 unweighted average over circle (Top Hat radius 75 km forASCAT‐625) instead of Hamming‐weighted area over square using the EUMETSAT L1B full resolution product and the 625 km grid contained in it

bull ASCAT‐625 shows more details than ASCAT‐coastal but is alsoa bit noisier because‐ less footprints contribute to a WVC notably for the mid

beam at low incidence angles‐ the spatial overlap of the three beams is reduced

IOVWST 2016

Introduction ASCAT‐625 CSRF

-134o

0o

01 - 0202 - 0303 - 04

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

04 - 0505 - 0606 - 07

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

07 - 0808 - 0909 - 10

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

-134o

0o

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

Red crosses SRF centresSolid square WVCDotted circle Aggregation area

IOVWST 2016

Introduction

bull Is it possible to define a better high-resolutionASCAT wind product by using optimised sampling from the EUMETSAT L1B full resolution product

Resolution

Overlap

Sampling

IOVWST 2016

Scheme for resolution enhancementbull Uniform sampling of start from mid‐beam antenna

footprints 113 or 56 km grid sizebull Adopt a value for R the radius of the aggregation areabull Select one row of WVCrsquos search contributing footprints from

each of the three beams and make aggregation table

bull Processing‐ Read in L1B data‐ Calculate average and average beam positionfrom aggregation table

Very efficient algorithm (lt 10 of total processing time)IOVWST 2016

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Introduction ASCAT‐625 heritage

bull ASCAT‐625 will become operational in the next AWDP release (AWDP 24)

bull Downscaling of ASCAT‐coastal product by a factor of 2 unweighted average over circle (Top Hat radius 75 km forASCAT‐625) instead of Hamming‐weighted area over square using the EUMETSAT L1B full resolution product and the 625 km grid contained in it

bull ASCAT‐625 shows more details than ASCAT‐coastal but is alsoa bit noisier because‐ less footprints contribute to a WVC notably for the mid

beam at low incidence angles‐ the spatial overlap of the three beams is reduced

IOVWST 2016

Introduction ASCAT‐625 CSRF

-134o

0o

01 - 0202 - 0303 - 04

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

04 - 0505 - 0606 - 07

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

07 - 0808 - 0909 - 10

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

-134o

0o

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

Red crosses SRF centresSolid square WVCDotted circle Aggregation area

IOVWST 2016

Introduction

bull Is it possible to define a better high-resolutionASCAT wind product by using optimised sampling from the EUMETSAT L1B full resolution product

Resolution

Overlap

Sampling

IOVWST 2016

Scheme for resolution enhancementbull Uniform sampling of start from mid‐beam antenna

footprints 113 or 56 km grid sizebull Adopt a value for R the radius of the aggregation areabull Select one row of WVCrsquos search contributing footprints from

each of the three beams and make aggregation table

bull Processing‐ Read in L1B data‐ Calculate average and average beam positionfrom aggregation table

Very efficient algorithm (lt 10 of total processing time)IOVWST 2016

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Introduction ASCAT‐625 CSRF

-134o

0o

01 - 0202 - 0303 - 04

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

04 - 0505 - 0606 - 07

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

07 - 0808 - 0909 - 10

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

-134o

0o

WVC 42 Fore

-134o

0o

WVC 42 Mid

-134o

0o

WVC 42 Aft

-1315o

0o

WVC 62 Fore

-1315o

0o

WVC 62 Mid

-1315o

0o

WVC 62 Aft

-1295o

0o

WVC 82 Fore

-1295o

0o

WVC 82 Mid

-1295o

0o

WVC 82 Aft

Red crosses SRF centresSolid square WVCDotted circle Aggregation area

IOVWST 2016

Introduction

bull Is it possible to define a better high-resolutionASCAT wind product by using optimised sampling from the EUMETSAT L1B full resolution product

Resolution

Overlap

Sampling

IOVWST 2016

Scheme for resolution enhancementbull Uniform sampling of start from mid‐beam antenna

footprints 113 or 56 km grid sizebull Adopt a value for R the radius of the aggregation areabull Select one row of WVCrsquos search contributing footprints from

each of the three beams and make aggregation table

bull Processing‐ Read in L1B data‐ Calculate average and average beam positionfrom aggregation table

Very efficient algorithm (lt 10 of total processing time)IOVWST 2016

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Introduction

bull Is it possible to define a better high-resolutionASCAT wind product by using optimised sampling from the EUMETSAT L1B full resolution product

Resolution

Overlap

Sampling

IOVWST 2016

Scheme for resolution enhancementbull Uniform sampling of start from mid‐beam antenna

footprints 113 or 56 km grid sizebull Adopt a value for R the radius of the aggregation areabull Select one row of WVCrsquos search contributing footprints from

each of the three beams and make aggregation table

bull Processing‐ Read in L1B data‐ Calculate average and average beam positionfrom aggregation table

Very efficient algorithm (lt 10 of total processing time)IOVWST 2016

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Scheme for resolution enhancementbull Uniform sampling of start from mid‐beam antenna

footprints 113 or 56 km grid sizebull Adopt a value for R the radius of the aggregation areabull Select one row of WVCrsquos search contributing footprints from

each of the three beams and make aggregation table

bull Processing‐ Read in L1B data‐ Calculate average and average beam positionfrom aggregation table

Very efficient algorithm (lt 10 of total processing time)IOVWST 2016

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Resolution enhancement ndash gaps in L1B

Gaps in L1B full resproduct

Can be handled byusing beam‐to‐beam time forsynchronisationwith WVC grid

IOVWST 2016

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Grid definition (56 km)

bull Grid size 56 km 200 WVCrsquos per row

bull 4 possible symmetricantenna patterns forlowest incidence WVC

bull Choose MX 6 SRFrsquos andmost circular (but MA remains to be investigated)

bull Choose symmetricfootprint pattern for eachWVC 1MXo (WVCrsquosalong row no longerequidistant)

CSRF for ASCAT-56 WVC 100

o WVC centretimes SRF centre 75 km aggregation radius

MetOp

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

M0

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

M4

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MA

83o 84o 85o 86o 87o 88o

-08o

-07o

-06o

-05o

-04o

MX

IOVWST 2016

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Scatterometer Science Conference 2016

ASCAT‐56August 1 2013

Pacific off Mexican coast

2deg times 2deg

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Libration

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

alon

g tr

ack

(km

)

fore-mid WVC 50fore-mid WVC 51

ASCAT-2MXo

-20 0 20 40 60 80

cross track (km)

-20

0

20

40

aft-mid WVC 50aft-mid WVC 51

ASCAT-113

bull To keep the antennas directed towards the Earth MetOp rotatesexactly once per orbit However MetOprsquos orbit is elliptical so thesatellite seems to ldquowigglerdquo along its orbit ndash aka libration

bull Use of aggregation table induces position differences between foreand mid beam (left) and between aft and mid beam (right) for WVC 50 and 51 (ASCAT-113 100 WVCrsquos per row)

Can be correctedfor by shifting theaggregation table

IOVWST 2016

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Libration (ASCAT‐113)

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

0 01 02 03 04 05 06 07 08 09 1Overlap ASCAT-2MXo

aft - fore

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

mid - aft

-180o -150o -120o -90o -60o -30o 0o 30o 60o 90o 120o 150o 180o

-60o

-30o

0o

30o

60o

fore - mid

No correction

Corrected

IOVWST 2016

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Aggregation table editing

bull With the libration correction the average position of eachbeam is shifted as close as possible to the preferred WVC position while retaining the aggregation pattern

bull The aggregation table thus doesnrsquot need to be very precise

bull Edit aggregation table manually for left fore and left midbeam and define it symmetrically for the other beams 1MXo‐IampS (improved and symmetrised)

IOVWST 2016

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

ASCAT 1MXo‐IampS aggregation

Twice as manycontributing

footprints for midbeam at low incidence but

almost the samespatial resolution

o Desired WVC centretimes SRF centre 75 km aggregation radius

MetOp

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

fore WVC 1 - 65

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

gt -10 dBgt -3 dBgt -2 dBgt -1 dB

fore WVC 66 - 100

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 1 - 43

-02o -01o 0o 01o 02o-02o

-01o

0o

01o

02o

mid WVC 44 - 100

IOVWST 2016

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Results

bull Buoy comparison (2475 collocations)

bull ASCAT‐1MXo‐IampS compares bestbull ASCAT‐1MXo‐IampS has lower and smaller average cone‐

distance than ASCAT‐625 and ASCAT‐1MXo (no results shown)

Product (ms) (deg) (ms) (ms)ASCAT‐625 099 173 148 161

ASCAT‐1MXo 100 173 146 165

ASCAT‐1MXo‐IampS 099 168 145 161

Precision 002 04 003 003

IOVWST 2016

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Results

ASCAT‐56 (1MXo‐IampS) ASCAT‐625

Less AR errors in frontal region for ASCAT‐56 IOVWST 2016

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Results ‐ overlap

092 061

060

)()(cos

2

FFddI

III

O

IOVWST 2016

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Resolution

bull Individual accumulated fore aft and mid beam areas do not exactly overlap

bull Common area defines resolution (all)

bull ldquoUncommonrdquo area presents noise due to wind variability

bull Resolution is rather constant over swath

IOVWST 2016

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Conclusions

bull It is possible to improve on current operational ASCAT products byexploiting the full resolution L1B product

bull Prorsquos‐ better statistics and better buoy comparison‐ fast aggregation algorithm

bull Conrsquos‐ WVC grid no longer equidistant

bull ASCAT‐1MXo‐IampS as example but other grid definitions still to beinvestigated (for instance grid size continuously decreasing withincreasing incidence angle)

bull Spatial resolution ~ 15 km seems lower limit due to asymmetricshape of single SRF and balance between resolution and sampling

bull Deconvolution techniques may work well for isotropicstable targetsIOVWST 2016

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS

Results ‐ overlap

Scatterometer Science Conference 2016

1MXo IampS