Breaking news --> SMOS new LEVEL 2 SM Version in ready! Dear All The long awaited SMOS V650 is now ready for release and thus for you to use! We (ESA and ESLs) have prepared it  tested it, run the reprocessing from beginning to now, and the operational processor is no ready to produce it giving you access to the whole data set! The main features of the new versions are described in the release note made available...

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Training at IISc, Bangalore on the use of Microwave... Are you in Bangalore next week ? and interested on learning about the use of microwave data (radiometers, SARs and Altimeters) then contact Prof. Muddu Sekhar to join us on this training. and the associated program:

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8 candles for SMOS!!!!!!!! (8/8) Happy Birthday SMOS ! (As you have guessed the eight "!" correspond to 8 candles .. upside down as SMOS is looking downward). Yes SMOS has been in space for eight years now and, for a satellite, this is starting to be a somewhat venerable. So....What is next? But first a quick appraisal: We have tried to depict in the previous blogs some of the achievements only...

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(Very) soon 8 candles for SMOS!!!!!!! (7/8) After a look back at oceans, soil moisture and their applications let's have a look at colder areas.... Actually during the SMOS early years we tried to get a cryosphere group  but with very limited success to say the least. Most of them were heavily involved with other missions with little time to spend on an L band radiometer of unfathomed relevance to their science. But...

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Soon 8 candles for SMOS!!!!!! (6/8) After the illustrations of some striking results over oceans, we can only marvel, especially as many other aspects were not covered.  Eight years ago we did not have any of such applications and science return. Those span from rainfall estimates over oceans to wind speed retrievals for strong winds (tropical storms, hurricanes and the like) where wind scatterometers do...

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Breaking news –> SMOS new LEVEL 2 SM Version in ready!

Category : L2

Dear All

The long awaited SMOS V650 is now ready for release and thus for you to use!

We (ESA and ESLs) have prepared it  tested it, run the reprocessing from beginning to now, and the operational processor is no ready to produce it giving you access to the whole data set!

The main features of the new versions are described in the release note made available with the new distribution. It capitalises as usual on the progresses made at level 1, but the most salient features are

  • the replacement of ECOCLIMAP by IGBP which enables to have i) an up to date land use map and ii) to be aligned with SMAP and Aquarius,
  • the use of CdF matching in mixed forest nominal pixels and much more accurate and
  • relevant DQX and Chi2
  • Finally the way the current files are updated is also improved.

As  a consequence the new version is « wetter » at high latitudes and around forested areas (with also higher VODs), more retrievals are successful. In terms of metrics with respect to our usual sparse and dense networks, both correlation coefficients and RMSE  are improved but also thereis no bias at all while the SDTE remains the same.

V651-SM

Difference (V650-V620) of averaged soil moisture (4 months per year January; April, July and October) during 7 years.

V650-Tau

Difference (V650-V620) of averaged vegetation opacity (4 months per year January; April, July and October) during 7 years.

Data and documentation available at the usual ESA / Array addresses

Note that the SM NRT are being updated. CATDS L3 will also be updated, but after we have corrected an issue with L3 temporal approach algorithm.

Have fun!

Training at IISc, Bangalore on the use of Microwave RS for Agro-hydrology

Category : Non classé

Are you in Bangalore next week ? and interested on learning about the use of microwave data (radiometers, SARs and Altimeters) then contact Prof. Muddu Sekhar to join us on this training.
annoucement_micro_training

and the associated program:

prog_micro_training

8 candles for SMOS!!!!!!!! (8/8)

Category : Non classé

Happy Birthday SMOS !

(As you have guessed the eight « ! » correspond to 8 candles .. upside down as SMOS is looking downward).

Yes SMOS has been in space for eight years now and, for a satellite, this is starting to be a somewhat venerable. So….What is next?

But first a quick appraisal:

We have tried to depict in the previous blogs some of the achievements only giving a very small part of what was done in science (According to Web of Science, 1065 papers since 1999 and an H index of 52. Are there many missions which can claim such a scientific footprint (I have done it for other missions but by sheer charity I won’t mention it here) and applications (several operational applications after only a few years (remember that SMOS in an explorer and makes measurements never done before to be compared to mission with a very long track record but very few operational applications)?

Now about the next steps…

After SMOS came Aquarius and SMAP. Each with a different instrumental concept but a common feature, L band radiometry.  When accounting for system differences (spatial resolution, view angle or revisit) one can say that  the missions provides excessively similar results (as shown for instance by Chen and Bindlish when the run the SMAP algorithm on SMOS data and merged the two). All have clearly demonstrated the potentialities, innovation and unicity of such measurements. There are simply no equivalent in any other domain! One mustn’t be fooled by proxies claiming to be measurements.

Back to our topic though. Where do we stand ?

Aquarius is no more (due to a platform issue incidentally) and SMOS or SMAP won’t last forever (a sad thought indeed). Considering the time it takes to make and launch a satellite, one may wonder why there are no current plans in Europe (or US) for a follow on.This is not due to a lack of information as we have shown (at EU workshops for instance) what consequences a data gap could bring and how unique were the measurements. We even sent EU 3 letters (Land, Ocean and Cryosphere) signed by several hundred scientist worldwide, and I was flabbergasted when I saw the answers we received: a kind of « not interested » form letter. Especially when one can see that Copernicus programme « application oriented » does not wish to consider L band continuation, but nurtures plans with exploratory missions or copies of planned missions. One may also wonder as we were also told that Copernicus does not consider earth explorer as potential candidates (irrelevant) while having one in their plans.

To make a long story short, agencies funded to develop explorers cannot support the follow ones (though they do it when it pleases them) and operational agencies prefer to support explorers than new operationally validated missions. Funny isn’t it?

All his dos not really make sense while our decision makers are, without any doubt, sensible people. So why are we in such a catch 22 scenario?

My belief is that the afore mentioned decision makers are no gurus in remote sensing and have to rely on counsellors who in many cases are no gurus either but keen to promote industries and other lobbies (so L band is obviously lacking an industrial backer!). Add to this mix a couple of hoity-toity advisers and pseudo specialists you get the big picture!

I am also a bit surprised to see that some operational agencies gave very stringent requirement before even considering assimilating SMOS. All the requirements were satisfied but to no significant result up to now except regular postponements to go operational while they are ready to assiimilate other datasets satisfying none of the requirements dictated for Smos (and proving to be quite neutral incidentally. As if they feared to have to update improve their model now that real measurements are coming in, killing their adjusting functions. I also heard people saying assimilating SMOS did not have much impact but forgetting to mention that their models are not designed to assimilate SSS….

But despite all this we haven’t lain on our oars and worked hard to prepare follow ons. Several options are open

The fastest would be to take existing concepts and update /improve from gained experience while the most efficient would be to review concept to achieve even more ambitious goals. We are also working on a improved SMOS concept with a typical native resolution of 10 km why other look at the potential L+P band concept. Adding active component is also an option to be considered. Finally we are also working on futuristic concepts !

End of November we will have a meeting at CESBIO to develop our strategywith respect to future L band missions and a meeting at ECMWF for the way forward in terms of applications.

A small note here about resolution by the way. Native means to me 3 db Beamwidth. Obviously there are techniques to dis aggregate and achieve higher resolution. I also refer to the  » dB footprint not the grid sampling. It is always amazing to me to see people (assumed to be competent and honest) comparing two different  instrument spatial resolutions by comparing the native of one with the sampling of the other. may be they simply do not know how to read the specs or limit their analysis to coffer table brochures (or are not honest / competent which never happens of course).

Also note that if no L band mission flies in the near future, the likelihood of loosing our very valuable protected bandwidth will become significant.

Well SMOS is 8 years old now (in space! but was initiated long before that) and we can only wish it many happy returns!

I believe we cannot end this little look back without thanking those who had the vision and supported our proposal at CNES and then ESAin teh mid ’90s, as well as mentioning and thanking enormously the team – led by Achim Hahne – who made our dreams come true and produced with CNES this wonderful mission, still running like clockwork (with all indicators bright green) after 8 years. We also have to thank the teams at ESA and CNES, in Toulouse, Frascati and Villafranca who – led by Susanne Mecklenburg – deliver all the excellent quality data in a very timely fashion (with two Near Real time products!) since launch. These two OP teams at CNES and ESAC do a terrific work!

And of course thanks to all the l band radiometry users and the ESLs who produced all this science and these applications!

I wish to end this set of post with an apology to all those I did not mention while they deserve to be. I made the posts on the spur of the moment with the illustrations I had at hand to realise soon after posting them that I could have added easily some other very relevant example. Sorry! I hope it will be an incentive  for those frustrated to put a post on this blog!

Long life to SMOS and thanks to all those who made and make it possible!

Yann

(Very) soon 8 candles for SMOS!!!!!!! (7/8)

Category : Data, L2, L3, L4

After a look back at oceans, soil moisture and their applications let’s have a look at colder areas….

Actually during the SMOS early years we tried to get a cryosphere group  but with very limited success to say the least. Most of them were heavily involved with other missions with little time to spend on an L band radiometer of unfathomed relevance to their science.

But some had ideas and looked at the data very quickly… and the number of research topics rapidly grew! I will try below to give a few examples.

Of course there were some basic uses. Considering the L Band penetration depth in dry ice it was expected to ave a very stable signal in Antarctica suitable for vicarious calibration. While G. Macelloni and colleagues at IFAC implemented a radiometer at Dome Concordia, F Cabot used the site to verify SMOS calibration and sensitivity and after used it to inter-compare with Aquarius and SMAP (using SMOS capability to reconstruct their main lobe characteristics through reconstruction). He routinely monitors the L band radiometers in orbit and with M. Brogioni follows the absolute calibration through the ground radiometer.

domeClegend

Caption: Temporal evolution of all sensors over Dome C (F. Cabot)

Over Antarctica several studies were performed (also funded by ESA) and products were made (available at CATDS) on estimation of internal ice-sheet temperature, estimation of ice thickness, indicator of the origin of ice-shelves variability, surface melting occurrences. But for me the most mind boggling result was obtained right at the beginning by Giovanni who identify definite signatures over lake Vostok which is some 3.7 km below the surface, while models indicate at best a 900 m penetration depth (G. Picard and M. Leduc Leballeur). Several potential explanations have been suggested but are yet to be validated.

Freeze thaw was expected to be a potential products and colleagues at FMI used the Elbara measurements in Sodankylä to devise a Freeze thaw algorithm. It is now quasi operational.

ft

Caption: Example for final soil freezing date on 2014 calculated from SMOS freeze/thaw data (K Rautiainen)

More novel the idea put forward by several scientists (G. Heygster, L. Kaleschke) to estimate thin sea ice thickness with SMOS. Now an operational product is being produced in Hamburg. It relies on the complementarity between Smos (sensitive below 75 cm thickness) and CryoSat only sensitive above a meter) the synergisms enable to track sea ice thickness globally whatever the thickness in a way, but also thin sea ice monitoring is a boon for ship routing around the Arctic (optimising between distance and ice to be broken through) and is of course very relevant for sea atmosphere exchanges.

anim

Caption: Temporal evolution of sea ice cover over the Arctic (L. Kaleschke)

Another ice cap of great interested is that of Greenland. The L band signatures are somewhat intriguing and several scientists are investigating it. But can already mention capturing significant melt event (as depicted by Mialon and Bircher on this blog) and some preliminary explanations for the different features seen.

Over land the first issue to tackle was that of the thick layers of organic soils whose dielectric constant are quite different from that of mineral soils (even the probes, if not calibrated properly, give wrong estimates). S Bircher and colleagues tackled the issue and developed both an improved dielectric model but also an adapted soils map to make good use of it. This constitutes a major step forward for the analysis of high latitudes. It will also lead to more adequate permafrost monitoring projects.

Finally I believe we are on the verge of another dramatic improvement with the very recent work done at WSL /Gamma by M. Schwank and colleagues and at FMI (K. Rautiainen and J. Lemmetyinen) as they found a way to infer snow density from SMOS data and then they are on the verge of extracting snow water content from L band radiometry.

For the cryosphere, these achievements and notably thins sea ice an snow density / water content are I believe very significant steps forward!

Stay tuned!

For further reading:

Bircher, S., Andreasen, M., Vuollet, J., Vehvilainen, J., Rautiainen, K., Jonard, F., Weihermuller, L., Zakharova, E., Wigneron, J.P., & Kerr, Y.H. (2016). Soil moisture sensor calibration for organic soil surface layers. Geoscientific Instrumentation Methods and Data Systems, 5, 109-125

Bircher, S., & Remote Sensing Editorial, O. (2017). L-Band Relative Permittivity of Organic Soil Surface Layers-A New Dataset of Resonant Cavity Measurements and Model Evaluation (vol 8, 1024, 2016). Remote Sensing, 9

Bircher, S., Demontoux, F., Razafindratsima, S., Zakharova, E., Drusch, M., Wigneron, J.P., & Kerr, Y.H. (2016). L-Band Relative Permittivity of Organic Soil Surface LayersA New Dataset of Resonant Cavity Measurements and Model Evaluation. Remote Sensing, 8

Kaleschke, L., Tian-Kunze, X., Maass, N., Beitsch, A., Wernecke, A., Miernecki, M., Muller, G., Fock, B.H., Gierisch, A.M.U., Schlunzen, K.H., Pohlmann, T., Dobrynin, M., Hendricks, S., Asseng, J., Gerdes, R., Jochmann, P., Reimer, N., Holfort, J., Melsheimer, C., Heygster, G., Spreen, G., Gerland, S., King, J., Skou, N., Sobjaerg, S.S., Haas, C., Richter, F., & Casal, T. (2016). SMOS sea ice product: Operational application and validation in the Barents Sea marginal ice zone. Remote Sensing of Environment, 180, 264-273

Lemmetyinen, J., Schwank, M., Rautiainen, K., Kontu, A., Parkkinen, T., Matzler, C., Wiesmann, A., Wegmuller, U., Derksen, C., Toose, P., Roy, A., & Pulliainen, J. (2016). Snow density and ground permittivity retrieved from L-band radiometry: Application to experimental data. Remote Sensing of Environment, 180, 377-391

Naderpour, R., Schwank, M., Matzler, C., Lemmetyinen, J., & Steffen, K. (2017). Snow Density and Ground Permittivity Retrieved From L-Band Radiometry: A Retrieval Sensitivity Analysis. Ieee Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 10, 3148-3161

Pellarin, T., Mialon, A., Biron, R., Coulaud, C., Gibon, F., Kerr, Y., Lafaysse, M., Mercier, B., Morin, S., Redor, I., Schwank, M., & Volksch, I. (2016). Three years of L-band brightness temperature measurements in a mountainous area: Topography, vegetation and snowmelt issues. Remote Sensing of Environment, 180, 85-98

Rautiainen, K., Parkkinen, T., Lemmetyinen, J., Schwank, M., Wiesmann, A., Ikonen, J., Derksen, C., Davydov, S., Davydova, A., Boike, J., Langer, M., Drusch, M., & Pulliainen, J. (2016). SMOS prototype algorithm for detecting autumn soil freezing. Remote Sensing of Environment, 180, 346-360

Ricker, R., Hendricks, S., Kaleschke, L., Tian-Kunze, X., King, J., & Haas, C. (2017). A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data. Cryosphere, 11, 1607-1623

Schwank, M., Matzler, C., Wiesmann, A., Wegmuller, U., Pulliainen, J., Lemmetyinen, J., Rautiainen, K., Derksen, C., Toose, P., & Drusch, M. (2015). Snow Density and Ground Permittivity Retrieved from L-Band Radiometry: A Synthetic Analysis. Ieee Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8, 3833-3845

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