SMOS blog

by the CESBIO team

Articles Taggés ‘Ocean’

Large scale SSS contrasts detected by SMOS and in situ SSS analysis in the tropical Pacific and Indian Oceans

6 mars 2013

Recent results from LOCEAN team

Variability in the tropical Pacific and Indian Oceans between 2010 and 2011 is very large linked to the ending 2009-2010 El Nino, 2010 strong La Niña and 2011 weak La Niña events, and to negative Indian Ocean Dipole (IOD) in 2010 (see Figure below).

figure1 Time series of SST anomalies in the four Niño regions from http://www.cpc.ncep.noaa.gov/data/indices/sstoi.indices in 2010-2011 and corresponding Indian Ocean Dipole (IOD) Index (SST difference between eastern and western equatorial Indian Ocean) from the Australian bureau of Meteorology.

Large scale SSS variability is very consistently observed on SMOS SSS maps (1) compared with ISAS SSS maps (2) derived from in situ (ARGO floats and ship data) measurements, as seen on the film. SMOS anomalies are often more contrasted than ISAS anomalies due to fresher SMOS SSS in fresh regions associated with rain (Boutin et al., 2013). Signal is much noisier from January to May due to worse SMOS SSS quality during commissioning phase in January-May 2010, but nevertheless spatial structures of anomalies remain very consistent with ISAS maps.

(1) SMOS SSS maps are generated using ESA reprocessing version 5 as described in J. Boutin, N. Martin, G. Reverdin, X. Yin and F. Gaillard, Sea surface freshening inferred from
SMOS and ARGO salinity: Impact of rain, Ocean Sci., 9, 183-192, doi:10.5194/os-9-183-2013, 2013.

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Posté dans CATDS, Cal/Val, L2, Ocean

Tags: CATDS Comparison Ocean sea surface salinity

SMOS TRAINING SESSION UPDATE

5 août 2012

Dear Colleagues

As promised some news on the training workshop!

First of all we received many applications – still counting - and we will have a difficult task selecting the happy few!

This will be done end of August with announcements beginning of September.

In the mean time here is the draft programme.

SMOS TRAINING SESSION
Toulouse, 5 – 9 November 2012

PROGRAMME

————————————————– Nov 5 ————————————————-

INTRODUCTION

AFTERNOON:

-   Welcome and overview over weekly programme
-   Distribution of material, allocation of computers, passwords, etc.
-   SMOS mission overview

————————————————– Nov 6 ————————————————-

FROM SATELLITE TO BRIGHTNESS TEMPERATURES

MORNING:

-   Mission characteristics
-   Data access and selection of products
-   Brightness temperature reconstruction, calibration, corrections

AFTERNOON:

-   Visualization of the SWATH based XY Brightness temperature products
- visualizing product content using Beam (and SMOSVIEW TBC)
- what we know about RFI
-   HV Brightness temperature products
- from swath based products XY2HV
- angle binned brightness temperatures products
-   Analyzing product content with scripts
- from specs (INDRA ESAC) to reader using Python
- SMOS and modeled brightness temperature comparisons, SMOS angular signature over water, etc. using Matlab

————————————————– Nov 7 ————————————————-

FROM BRIGHTNESS TEMPERATURE TO GEOPHYSICAL PRODUCTS

PARALLEL SESSION 1: LAND PRODUCTS

MORNING:

-   The soil moisture retrieval algorithm
-   Soil moisture products visualization/content
-   Reading and analyzing data – RWAPI Matlab

AFTERNOON:

- Running the soil moisture retrieval processor on custom data

PARALLEL SESSION 2: OCEAN SALINITY

- The SSS retrieval algorithms
- In the ESA Operational chain
- In the CATDS Research Center chain (TBC)
- The along swath (level 2) SSS product
- Definition of flags
- Impact of flags
- Calibration-validation using in situ SSS
- Reading, visualization under Matlab and Python

————————————————– Nov 8 ————————————————-

TEMPORAL SYNTHESIS PRODUCTS

PARALLEL SESSION 1 : LAND PRODUCTS

MORNING:

-   Multi-orbit soil moisture retrievals with SMOS – algorithm description
-   3 days, 10 days , monthly temporal synthesis products
-   Interactive visualization of the products using Panoply

AFTERNOON:

- Reading and analyzing the CATDS Products
- Reading and analyzing NetCDF products
- Fast analyses using NCO

PARALLEL SESSION 2: OCEAN SALINITY

- CATDS Research Center SSS maps (sortings based on yearly data set TBC)
- Combination of multi-orbit SSS retrieved from SMOS ESA processor, importance of quality indicators

————————————————– Nov 9 ————————————————-

APPLICATIONS USING SMOS DATA

MORNING:

- Overview of applications using SMOS products: data disaggregation, assimilation, root zone soil moisture, impact of rain on salinity stratification, tracking hurricanes, snow/ice
- Feedback from CAL/VAL teams – an open round table

WRAP-UP

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Posté dans CATDS, Data, L1, L2, L3, L4, Tools, Training

Tags: Brightness temperature CATDS DPGS level 3 Ocean RFI SM Retrieval vegetation opacity retrieval

UPDATE on the SMOS products versions

26 avril 2012

As indicated earlier the New reprocessed SMOS data is available. It is the so called version 5

The different readme files are available on the ESA web site

ALL the LEVEL 1, 2SM and 2 OS have been reprocessed from January 2010 to the end of 2011 and the processor (operational) is also running with the very same version so from January 2010 to April 2012 all the data has been processed uniformly and is available from ESA

For soil moisture a new version of the Level 2 Soil Moisture processor (V5.51) has been deployed in the operational chain on 24 April 2012. The first data set generated with the new processor has the start acquisition time of 23 April 2012 08:35 UTC.

The main difference between V5.51 and previous V5.00 is the change of the dielectric constant model used in the retrieval algorithm. Processor version V5.51 uses the Mironov formulation instead of the Dobson Model. This change improves the soil moisture estimates, increases the number of successful retrievals over dry and warm surfaces and reduces extreme values of soil moisture.

The processor improvements and other associated information are summarised in the Level 2 SM read-me-first note.

Soil Moisture data users are strongly encouraged to consult the above mentioned Level 2 SM read-me-first n

Except for very arid areas we do not expect drastic changes we will not reprocess the whole data just now.

FEED BACK is most welcome as usual

The SMOS TEAM

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Posté dans Cal/Val, Data, L1, L2, Non classé

Tags: Brightness temperature DPGS global cover Ocean reprocessing sea surface salinity SM Retrieval

Do You Remember B15J? Well, was a good buoy, but wandered into the ocean away from home and … melted away!

4 mars 2012

After the drifting iceberg (identified by SMOS blog followers as the B15J) was spotted on SMOS data, it has become attractive to follow the movement of this massive « natural buoy », serving as the oceans current indicator.

The iceberg trajectory has been determined from the SMOS browse data, and it is charted as a function of the first Stokes parameter (at the incidence angle 42.5).

Animation based on consecutive single passes shows iceberg location during last three months.

Note, that in the range between 114-140 K the color scale has been modified on purpose. This gives better ability to distinguish moving B15J from the surrounding open water, but also depicts regions characterized by the same brightness temperature range as the tracked iceberg.

When in the middle of October 2011 B15J started to move towards the equator, straying from Antarctica, its brightness temperature started to decrease steadily. The DGG pixels belonging to the iceberg area and having maximum intensity of the first Stokes parameter have been extracted to examine polarimetric characteristics of the tracked object. Sample of polarimetric characteristics, grouped into three months sets, confirms significant drop-off of the brightness temperature.

Unfortunately at the end of December 2011, the signature of B15J were barely apparent. The iceberg vanished in the Pacific Ocean, making further tracking not feasible.