SMOS-BEC – Barcelona (Spain)
OTT rate deployment GPOD experiment
SMOS vs ARGO comparison
QWG10 – ESRIN 4-6 February 2013
Justino Martínez & Carolina Gabarróand BEC team
SMOS Barcelona Expert CentrePg. Marítim de la Barceloneta 37-49, Barcelona SPAINE-mail: [email protected]: www.smos-bec.icm.csic.es
SMOS-BEC
Motivation of GPOD experimentAfter last reprocessing campaign important differences in SSS L3 maps were detected.
DPGS operational L2 products distributed by DPGS in real-time
High variability in SSS bias These differences are correlated between ascending and descending
ReprocessedLast reprocessing campaign from 2010/01/12 to 2011/12/22 More stable behavior
Reason for the differences? Difficult to conclude, different processing conditions were applied:
L2 data set OTT L2 configuration file version L1/L2 processors versions TEC
DPGS operational
Monthly OTTApplied two weeks
after NIR events
2 different versionsfrom 2011/10/20 to 2012/01/22
version 021_8Tg_TEC_gradient=20
Tg_num_outliers_max=50
version 022_8 from 2012/01/23
Year 2011: Wide variety of L1/L2 versions
Year 2012:Last versions of L1/L2
processors
predicted
reprocessed15-day OTT
Validity centered on NIR calibration events
Version 022_8Tg_TEC_gradient=5000
Tg_num_outliers_max=20Last versions of processors consolidated
2/20different different same only 1.5 months different
SMOS-BEC
Tested zones
Zone Lat Lon Description
Global 60S : 60N 180W : 180E Tropics and mid-latitudes
Tropic 30S : 30N 180W : 180E Tropics
122 30S : 0N 150W : 120W A region of the South Eastern Pacific
124 24S : 10S 165E : 165W A region of the South Western Tropical Pacific
126 10S : 10N 180W : 180E Equatorial Oceans
127 15N : 37N 50W : 0E North Atlantic (Tarfaya model region)
131 60S : 40S 180W : 180E Southern Ocean
132 5N : 15N 110W : 180W Intertropical Pacific
133 45N : 60N 170E : 140W A region of the North Pacific
3/20
SMOS-BEC
BINNING PROCESS
HIGH WIND FILTER
POOR GEOPHYSICAL
POOR RETRIEVAL
VALID L1C RATE
ACROSS TRACK FILTER
L2 - REPR - DPGS total L1c measures <= 90
L2 filtering rules
valid L1c measures less than
total L1c measures / 3
L2PP CNF - fileMax iterations reached > 20Poor fit qualityHigh retrieval sigma > 5Values out of range (0 .. 42) …
L2PP CNF - fileSuspect ICE > 50%Rain > 2 l/hMany Outliers > 20%Galactic noise > 10%#measures < 30 …
Wind speed > 12 m/s
1x1 grid size10 days
average overretrieved SSS
-every 3 days
+/- 400 km
4/20
SMOS-BEC
Argo values computation
Robust interpolation applied to 7.5 m depth
1x1 grid size10 days
average overArgo SSS
-every 3 days
BINNING PROCESS
3 interpolation methods on T and SSS
SSS SSS Argo 100
5SSS
SSSSSS
SSS31SSS
i
3
1ii
Differences between the mean and each interpolated T and SSS below the 5%
compare cells to study thetemporal evolution of
SMOS-ARGO
5/20
SMOS-BEC
Differences DPGS vs reprocessed
ASCENDING
MEAN(SMOS-ARGO)
DPGS shows high temporal variations
Oscillations not clear correlated with NIR
Pattern independent of the zone. Linked to the OTT generation zone?.
122South Eastern Pacific - OTT
124South Western Tropical Pacific
127Tarfaya
GLOBAL
131Southern Ocean
6/20
SMOS-BEC
Differences DPGS vs reprocessed
DESCENDING
MEAN(SMOS-ARGO)
Tropics
Correlation: Oscillations take place with the same period in ascending and descending. Maxima at
February/March May/June October/November
.
122South Eastern Pacific - OTT
126Equatorial Oceans
131Southern Ocean
GLOBAL
7/20
SMOS-BEC
Differences DPGS vs reprocessed
Descending case:SUN affects OTT generation in Feb/Mar and Oct/Nov
Ascending case:SUN effects OTT generation in May/June
A fast response in OTT deployment is critical in a rapidly changing environment as when Sun is crossing FOV (in DPGS the OTT is computed using L1C from 1-2 weeks earlier and applied during a month)
ASCENDING DESCENDING
SUNSUNSUN
As reported by ARGANS: Sun
in OTT
8/20
GLOBAL
SMOS-BEC
G-POD study
Comparison study focused in the OTT deployment rate.
Will increasing the OTT generation rate solve the problem?
G-POD Recently reprocessed data using G-POD system from 2011/12/23 to 2012/02/29
L2 data set OTT VERSIONS IN THIS PERIOD TEC
DPGS operationalMonthly OTT
Applied up to two weeks after NIR events
L2 configuration file 022_8Tg_TEC_gradient=5000
Tg_num_outliers_max=20
L1 processor: 5.04L2 processor: 5.50
predicted
G-POD15-days OTT
Validity start time matches the NIR calibration events
L2 configuration file 022_8L1 processor: 5.04L2 processor: 5.50 predicted
9/20
different same same
SMOS-BEC
G-POD study
Ascending
GLOBAL60S:60N
MEAN(SMOS-ARGO)Descending
Purple line: Reprocessing campaign. It can be compared with G-POD experiment results (red line)
Red line: G-POD experimentVery different from DPGS (blue line)
At a first glance it seems to improve results but it is necessary to carry out a more accurate study10/20
SMOS-BEC
Analysis procedureWe depart from 10-day SSS maps computed every 3 days
Our target is to compare temporal stability of G-POD and DPGS
Problem: low number of points in our time series Proposed solution: how well fit our series to a straight line?
Procedure to quantify the degree of improvement
1. Compute drift (linear fitting) f(t)=at +b of each time series y(t) (G-POD and DPGS)We use the nonlinear last-squares Levenberg-Marquardt method algorithm to find linear fitting (a and b) and its error (Da and Db)
2. Substract dritf to time seriese(t) = y(t) - f(t); De(t) = Dy(t) + Df(t)
3. Compute a measure about how far is each point of the value e=0
This measure d can be computed for each point (L3 maps) and compare histograms. The lower d, the best fit
11/20
SMOS-BEC
Results by zone
GLOBAL
ASCENDING
In this case 15-days OTT introduces a clear Improvement
1
2
3
12/20
Each point indicates the central date of 10-days L3 mapsHorizontal errorbars include each 10-days period. Vertical errorbars indicate the error of the mean.
SMOS-BEC
Tropics
ASCENDINGResults by zone
122South Eastern Pacific - OTT
13/20
SMOS-BEC
124South Western Tropical Pacific
ASCENDINGResults by zone
126Equatorial Oceans
14/20
SMOS-BEC
127Tarfaya
ASCENDINGResults by zone
131Southern Ocean
15/20
SMOS-BEC
Tropics
DESCENDINGResults by zone
122South Eastern Pacific - OTT
16/20
SMOS-BEC
124South Western Tropical Pacific
DESCENDINGResults by zone
126Equatorial Oceans
17/20
SMOS-BEC
127Tarfaya
DESCENDINGResults by zone
131Southern Ocean
18/20
SMOS-BEC
Conclusions
- A fast response in OTT generation and deployment is critical in a rapidly changing environment as when Sun is crossing the FOV
- Two strategies:
Center L1C orbits used for OTT generation in the OTT validity period
Generate OTT more frequently (15 days) To implement this option it is necessary an automatic method to generate OTT with the same quality as the current method (manual)
L2 production should be in delayed mode
19/20
SMOS Barcelona Expert Centre (SMOS-BEC)Pg. Marítim de la Barceloneta 37-49, E-08003 Barcelona, SPAINTel. (+34) 93 230 95 00; Fax. (+34) 93 230 95 55URL: www.smos-bec.icm.csic.es
SMOS-BEC
Differences DPGS vs reprocessedASCENDING
21/20
SMOS-BEC 22/20
Differences DPGS vs reprocessedASCENDING
SMOS-BEC
Differences DPGS vs reprocessedDESCENDING
23/20
SMOS-BEC 24/20
Differences DPGS vs reprocessedDESCENDING
SMOS-BEC 25/20
G-POD results by zoneASCENDING
SMOS-BEC 26/20
G-POD results by zoneASCENDING
SMOS-BEC 27/20
G-POD results by zoneDESCENDING
SMOS-BEC 28/20
G-POD results by zoneDESCENDING
SMOS-BEC 29/20
G-POD results by zoneASCENDING
SMOS-BEC 30/20
G-POD results by zoneASCENDING
SMOS-BEC 31/20
G-POD results by zoneDESCENDING
SMOS-BEC 32/20
G-POD results by zoneDESCENDING
SMOS-BEC 33/20
G-POD results by zoneASCENDING
SMOS-BEC 34/20
G-POD results by zoneASCENDING
SMOS-BEC 35/20
G-POD results by zoneDESCENDING
SMOS-BEC 36/20
G-POD results by zoneDESCENDING
