Aquarius / SMAP Ocean Roughness and SSS

Transcription

1 Aquarius / SMAP Ocean Roughness and SSS Alex Fore, Simon Yueh, Wenqing Tang, Akiko Hayashi L2B and L3 data are available at: h2p://ourocean.jpl.nasa.gov 216 California InsItute of Technology, Government Sponsorship acknowledged

2 SMAP AND OCEAN ROUGHNESS

3 Excess Surface Emissivity SMAP GMF vs Aquarius GMF: A; T12323 SMAP A eh AQ A eh SMAP A ev AQ A ev SMAP and Aquarius roughness model agree well WindSAT Wind Speed [m/s]

4 Excess Surface Emissivity Cosine Amplitude 2.5 x SMAP GMF vs Aquarius GMF: A1; T12323 SMAP A1 eh AQ A1 eh SMAP A1 ev AQ A1 ev WindSAT Wind Speed [m/s]

5 Excess Surface Emissivity Cosine Amplitude 2 x SMAP GMF vs Aquarius GMF: A2; T12323 SMAP A2 eh AQ A2 eh SMAP A2 ev AQ A2 ev WindSAT Wind Speed [m/s]

6 1 SMAP GMF vs Aquarius GMF: HH bias:.62; VV bias:.32 SMAP HH vs PALSAR:.3; R SMAP A HH 26 AQ A HH PALSAR A HH 28 SMAP A VV AQ A VV WindSAT Wind Speed [m/s]

7 SMAP GMF vs Aquarius GMF: A1/A; R1217 SMAP A1/A HH AQ A1/A HH SMAP A1/A VV AQ A1/A VV WindSAT Wind Speed [m/s]

8 .5 SMAP GMF vs Aquarius GMF: A2/A; R SMAP A2/A HH.1 AQ A2/A HH SMAP A2/A VV AQ A2/A VV WindSAT Wind Speed [m/s]

9 SMAP GMF vs Aquarius GMF: HV bias:.37 VH bias:.14; R SMAP A HV SMAP A VH AQ A HV WindSAT Wind Speed [m/s]

10 SMAP SAR data extends L- band roughness model to extreme winds Blanca 6/4/215 13Z; NHC advisory indicates 5 m/s sustained 6 m/s gusts Image is VIIRS Suomi 6/4/ UTC

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14 SMAP L1C Blanca at > 25 km & < 45 km from eye location Upwind (wdir opposite look dir) Tangential Wind Direction HH VV HH GMF VV GMF

15 24 SMAP L1C Blanca at > 25 km & < 45 km from eye location XPOL XPOL GMF Upwind (wdir opposite look dir) Tangential Wind Direction

16 AQUARIUS AND SMAP SSS

17 (a) ARGO May 215 (b) HYCOM May 215 (c) Aquarius May 215 (d) SMAP TB -only May 215

18 TB SSS Processing Compute delta TB using ancillary data and model Average over each day; use 8 day median filtered value Decimated by fore/a` x asc/dec Grid into a 25 km L2A swath grid a la RapidSCAT Gridding method oversamples observaions onto the grid. EffecIve resoluion is somewhat larger than 4 km EsImate wind speed and salinity using constrained objecive funcion minimizaion F (spd, sss) = X i apple TB,i T m B,i (spd, sss, anc dir, anc swh, anc sst) NEDT i 2 spd spd anc 2 +, 1.5m/s

19 j+1 L2A Gridding Mean Number of L1B TBs per SWC Mean Number of L1B TBs per look in a SWC H/Fore H/Aft V/Fore V/Aft 2 j Cross Track Index j-1 25 km i-1 i i+1 Aggregate NEDT By Flavor Aggregate NEDT By Flavor H/Fore H/Aft V/Fore V/Aft Cross Track Index

20 L2B SWC 2.5 SMAP Salinity Difference to HYCOM Salinity Difference [psu] CAP Bias:.5 TB Only Bias: CAP RMS:.74 TB Only RMS: WindSat / SSMI/S Wind Speed [m/s]

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24 SMAP/AQ APDRC Stats for May 215 SSS Bias [psu] AQ:.6 AQ/CAP:.9 SMAP/TB:.4 SMAP/TBADJ:.1 SMAP/CAP:.2 SMAP/RSS: Latitude [deg]

25 SMAP/AQ APDRC Stats for May 215 AQ:.2 AQ/CAP:.19 SMAP/TB:.28 SMAP/TBADJ:.24 SMAP/CAP:.24 SMAP/RSS:.27 SSS STD [psu] Latitude [deg]

26 .26 SMAP/AQ APDRC Stats for May 215 vs Averaging Window SSS STD [psu] AQ.12 AQ/CAP SMAP/TB.1 SMAP/TBADJ SMAP/CAP 1 SMAP/RSS 1 1 Window Size Squared

27 Summary SMAP provides addiional source of L- band ocean roughness models SMAP- based models agree very well with Aquarius for normal winds (say up to 2 m/s). SMAP sampling enables pushing the models to hurricane/extreme winds, where some evidence that Aquarius roughness model isn t quite right. SMAP can coninue the record of global SSS maps from space. Accuracy is not as good as Aquarius but is close. The STD with respect to APDRC is mostly between.1 to.2 psu Loss of Radar affects the salinity retrievals significantly. Zonal biases sill an issue for SMAP, possible due to T B calibraion Data available at: ourocean.jpl.nasa.gov V1. based on validated data release (ongoing) V1.1- beta based on most recent radiometer data (3/15-2/16) V2 expected to be release near end of April, based on v1.1- beta.

28 Flow Chart of TB- only SSS Processing Ancillary data L1B TB L1B data match-ups l1b to dtb match-up processing l1b to l2a L2A T B by rev 8day median filter L2B data match-ups l2a to l2b T B vs time L2B SSS/WSPD

29 L3 Map Data Mask Within +/- 5 degrees laitude. Not in a few regions: Amazon / Congo / Ganges river ouilows. China RFI region. East Pacific region. More than 3 km from coast for zonal stats. All of various window averages completely full for plots versus window size (i.e. same map pixels for all). EffecIvely dilates excluded regions out to max of +3 pixels away from land / or other regions Use exactly the same map pixels for all data products!

30 SMAP T B CorrecIon EsImated delta TB correcion as a funcion of laitude and Ime. Smoothed over 8 day repeat period.

31 Ascending / Left / DTBH 1 Ascending / Right / DTBH Q2 15 Q3 15 Q4 15 Q1 16 Q2 16 Decending / Left / DTBH 1 1 Q2 15 Q3 15 Q4 15 Q1 16 Q2 16 Decending / Right / DTBH Q2 15 Q3 15 Q4 15 Q1 16 Q Q2 15 Q3 15 Q4 15 Q1 16 Q Ascending / Left / DTBV 1 Ascending / Right / DTBV Q2 15 Q3 15 Q4 15 Q1 16 Q2 16 Decending / Left / DTBV 1 1 Q2 15 Q3 15 Q4 15 Q1 16 Q2 16 Decending / Right / DTBV Q2 15 Q3 15 Q4 15 Q1 16 Q Q2 15 Q3 15 Q4 15 Q1 16 Q2 16 1

32 L2B SWC SMAP Speed Difference to WindSat / SSMI/S TB Bias:.11 TB RMS: Speed Difference [m/s] WindSat / SSMI/S Wind Speed [m/s]

33 L2 Footprints 2.5 AQ Salinity Difference to HYCOM Salinity Difference [psu] ADPS Bias:.9 ADPS RMS: SSMI/S Wind Speed [m/s]