SMOS research products for the Cryosphere in Antarctica

Category : L3, L4

The aim of the CryoSMOS project, funded by the European Space Agency (ESA) and led by IFAC (Florence, Italy), is to evaluate the ability of SMOS observations to retrieve glaciological parameters or to monitor climatic processes in Antarctica. The study focused on some broad areas of the continent having specific physical characteristics: the Antarctic Plateau, the ice-shelves and the coastal region. Four SMOS derived research products have been developed:

1) Estimation of the internal ice-sheet temperature

Contact : Giovanni Macelloni, g.macelloni@ifac.cnr.it – IFAC, Florence, Italy

2) Estimation of ice thickness

Contact : Niels Skou, ns@space.dtu.dk,DTU, ns@space.dtu.dk – Technical University of Denmark – Denmark

3) Indicator of the origin of ice-shelves variability;

Contact : Lars Kaleschke, lars.kaleschke@uni-hamburg.de, UHAM – University of Hamburg, Germany

4) Surface melting occurrence

Contact : Ghislain Picard, ghislain.picard@univ-grenoble-alpes.fr,IGE – Institut des Geosciences de l’Environnement – Grenoble, France

The data are available from the CATDS and can be found here (free)

Information regarding these products can be found here

More information is available there

Two examples are shown in the figures below. The top most represents the temperature of the ice packs at a depth of 500m. The lower one gives the number of days of melt in 2010/2011.

Tice@-500m in SM_TEST_MIR_ITUDP4_20100101T0000

fig_melt_nbdays_smos_2010-2011

PhD or Postdoc Position in Satellite-Based Data Assimilation for Soil Moisture Estimation

Category : L4, position opening

Please note

On-line vacancy advertisement:
https://icts.kuleuven.be/apps/jobsite/vacatures/53807202

PhD or Postdoc Position in Satellite-Based Data Assimilation for Soil Moisture Estimation

Our team: http://ees.kuleuven.be/bwb/index.html

Soil moisture is a key variable in the water, energy and carbon cycle over land. The objective of this project is to merge large-scale land surface simulations with satellite-based microwave observations from the ESA Soil Moisture Ocean Salinity (SMOS) and NASA Soil Moisture Active Passive (SMAP) missions, using an advanced data assimilation scheme which corrects for both the random and persistent errors in soil moisture estimates. The improved soil moisture time series will help enhancing subsequent predictions of flooding, landslides, soil and vegetation carbon, deeper groundwater and the atmospheric boundary layer.

We are searching for an enthusiastic researcher with a keen interest in land surface processes to implement advances to a global land surface data assimilation system. You will be part of the Department of Earth and Environmental Sciences, Division Soil and Water Management, at the KU Leuven (Belgium), working under the supervision of prof. dr. ir. Gabrielle De Lannoy.

Profile
==========
- Master (for PhD position) or PhD (for postdoc position) degree in Hydrology, Civil or Environmental Engineering, Meteorology, Remotely Sensed Earth Observation, Physics, Mathematics, Computer Sciences, or equivalent
- Experience with data-processing applications such as Matlab/Python, IDL,GrADS, R, or other; interest in (for PhD position) or strong experience with (for postdoc position) programming and scientific computing
- Excellent motivation and grades
- Creative, critical, analytical and innovative mindset
- Ability to work independently
- Excellent written and oral communication skills in English

Offer
==========
- For PhD position: PhD scholarship for 4 years; support and training to PhD students through the Arenberg Doctoral School (https://set.kuleuven.be/phd)
- For postdoc position: 2-year position with a competitive salary; support in career development
- Multi-disciplinary and international professional environment
- Leuven is a charming historical university town, located in the heart of Western Europe

Interested?
==========
Applicants should submit their resume, along with a motivation letter and two names for possible references on-line. The starting date is October 1, 2016. For more information please contact prof. dr. ir. Gabrielle De Lannoy, tel.: +32 16 37 67 13, mail: gabrielle.delannoy@kuleuven.be.

You can apply for this job via the online application tool until September 1, 2016: http://www.kuleuven.be/eapplyingforjobs/light/53807202

Was 2015 a « DRY » year? and what about 2016?

Category : CATDS, L4

Several extreme drought events occurred in 2015 around the globe. At CESBIO, combining hydrological modelling and remotely sensed surface soil moisture from SMOS, we monitored a number of them. We used CATDS (Centre Aval de Traitement des données SMOS) products.

The aproach was to use our root zone soil moisture information derived from SMOS to infer a water scarcity index. Water scarcity in the root zone (0-1.5m) is actually an efficient early warning system for agricultural droughts.

droughts_2015_albitar

The figure above shows 5 of the major droughts which occurred in 2015. The small focus maps show the drought index during the drought events in each of the regions of interest. The losses caused by these droughts amount to billions.

So the next question is: are we facing long drought events that can impact food security at global scale?

In 2016 we may see even worse conditions. Our drought index seem to provide an alarming forecast. This was showcased by ESA during the Living Planet Symposium LPS2016 with this post using our latest root zone soil moisture map (see Water for crops – the SMOS root zone soil moisture).

We also produced the drought index map over North America for 2016 and it seems that after the Alberta fires and last year drought in the West coast of the US, the Eastern coast is now at risk. This forecast may change but it is clear that extremes conditions are breaking very old records, beyond the contribution of the El-Nino effect.

drought_index_north_america_2016

SMOS, AMSR-2 and SMAp join forces to track Hurricanes!

Category : L3, L4, Ocean

N Reul and colleagues looked at the signatures of 3 co-evolving 2015 major Hurricanes from 22 Aug to 9 September 2015 in the East and Central tropical Pacific  using SMOS, SMAP and AMSR-2 observations (beyond others)

from Nicolas REUL (IFREMER) from teh SMOS + Storm evolution project (ESA)

Modis-and-SMOS

Legend: true-colour composite from the MODIS instrument on NASA’s Terra satellite and SMOS surface wind speed amplitude of hurricanes Kilo (left), Ignacio (centre) and Jimena (right) on 29 August 2015. All three were category-4 hurricanes and spanned the central and eastern Pacific basins. The bright bands in the images are sunglint where solar radiation from the Sun has reflected from Earth back to the satellite sensor.

This year sees a strong El Niño event which causes much higher temperatures than normal in the upper layers of the Tropical East Pacific. The available surplus heat favors an increased occurrence of Tropical Cyclones and storms. According to the National Oceanic and Atmospheric Administration (NOAA), this season has been ranked as the fifth most active hurricane season within the Eastern Pacific since 1971.  In a normal season, the average number of Major Hurricanes (Category 3 and plus in the Saffir-Simpson scale) is expected to be 3 whereas this year already 8 Major Hurricanes have occurred.  At the end of August, three Category 4 hurricanes (named Kilo, Ignacio and Jimena) developed in parallel in the vicinity of Hawaii which MODIS and SMOS sensors were well able to capture.

Several types of satellites observations are available to characterize surface winds over the ocean such as active scatterometer radars and passive low-frequency radiometers operating in C and L-band. The advantage of using such radiometers, being an all-weather tool, lies in detecting extreme wind speed (above 33 m/s, i.e., hurricane force) which scatterometers are not able to detect. Three such radiometers, namely, the ESA/SMOS and the recently launched NASA/SMAP L-band and the JAXA/AMSR-2 C-band, are now available to provide such observations.

SMOS surface Tbs and wind speed products along SMOS swaths were determined using the algorithm of  Reul et al., 2012 and updated in Reul et al., 2015. Image Reconstruction based on JRECON (J. Tenerelli, 2011). SMOS Level 1b Tbs are retrieved at antenna level and are further corrected for extra-terrestrial sources contributions, smooth sea surface emission, and atmospheric path effetcs to estimate a storm-surface induced Tb residual. A Quadratic Wind speed GMF is applied to the First Stokes parameter residual  to obtain U, the surface wind speed. Current validation reveals an rms of ~5 m/s up to 50 m/s with respect SFMR flight data or H*Wind analysis at the same spatial resolution than SMOS.

AMSR-2 surface winds are obtained using the  Algorithm developed by Zabolotskikh et al. (2013, 2015a,b) which involves the combined used of highest frequency Chanels (for rain retrieval) and atmosphere corrected 6.925 and 7.3 GHz channels for surface wind inversion.

SMAP: Level 1B data from NSIDC are used, surface first-stokes residual contributions are evaluated  (corrections for atmospheric, cosmic background reflections and smooth ocean surface emission), data with significant galactic reflections are not used  (asc fore beam data are not considered). GMF of Reul et al. 2015 developed for SMOS is applied to retrieved SWS. A systematic offset of -5m/s was added to the retrievals for consistency with ECMWF & NCEP winds for winds <20 m/s)

Thanks to the density of observations available from these 3 missions, the evolution of surface wind speed under tropical storms can now be monitored with an unprecedented spatial and temporal resolution. The example of the 3 co-evolving hurricanes in the East Pacific demonstrate this capability with an ensemble of 121 satellite swath intercepts of the 3 storms obtained by combining the data from the 3 sensors over a period of about 15 days (22 Aug to 7 Sep). The below animation shows the time-series mosaic of surface wind speed measurements under Hurricanes Kilo, Ignacio and Jimena. Data from the three satellite microwave radiometer missions: ESA’s L-band SMOS, NASA’s L-band SMAP and Japan’s C-band AMSR-2 are combined to reveal the track of each hurricane and maximum wind speed measured by each sensor at the ocean surface during the period.

see –> winds from SMOS, AMSR-2 and SMAP

wind-speed-contours-3Brothers

Caption: Contours of the domains showing the maxima of surface winds obtained from the combined multiple observations of SMOS, SMAP and AMSR-2 sensors from 22 Aug to 9 Sep 2015 showing the high wind trails over Hurricanes Kilo and Loke (left), Ignacio (center), Jimena (right).

Comparison of the Maxima of winds from the 3 satellites with Best-Track Maximum winds is shown here below.

Max-Wind-kilo-Ignacio-Jimena

Caption: Time series of the Maximum Sustained wind speed as provided by TC’s center (NOAA/HRD and NHC) together with the Maximum wind estimated from SMOS, SMAP and AMSR-2 fro Jimena (top), Ignacio (middle) and Kilo (bottom).

Limitations in the highest wind domains is not due to Tb saturation but to the 30-40 km spatial resolution smoothing effect (Highest-wind generally occur in a narrow region of radius < ~100km around the eyes with very high Wind speed radial gradients).

Key characteristics of hurricanes, such as the radii of wind speeds above a certain threshold (i.e. 34, 50, 64 and 84 knots), can now be captured more often in far more detail. This will greatly improve the representation of initial conditions of Tropical Cyclones in Numerical Weather forecasting systems and hence their prediction.

Interestingly, the higher resolution in space and time of the surface forcing that is gained by the merging of the data from these 3 low MW frequency sensors  will certainly help inferring better understanding of the ocean-atmosphere interactions in TCs:

sst_wake_3brothers

Caption: Sea Surface Temperature anomalies (in degrees Celcius) reveal cold-water wakes trailing behind hurricanes Kilo, Ignacio, and Jimena highlighting the power of hurricane winds to violently stir the upper ocean and bring cooler waters at depth to the ocean surface.

See as well a recent ESA web-story on the same topic

References

Reul, N., J. Tenerelli, B. Chapron, D. Vandemark, Y. Quilfen, and Y. Kerr (2012), SMOS satellite L-band radiometer: A new capability for ocean surface remote sensing in hurricanes, J. Geophys. Res., 117, C02006, doi:10.1029/2011JC007474.

Reul, N. et al, A revised L-band radio-brightness sensitivity to extreme winds under Tropical Cyclones: the 5
years SMOS-storm database, submitted to Remote Sensing of Environment, 2015.

E. V. Zabolotskikh, L. M. Mitnik, and B. Chapron, “New approach for severe marine weather study using satellite passive microwave sensing,” Geophys. Res. Lett., vol. 40, no. 13, pp. 3347–3350, 2013.

E. Zabolotskikh, L. Mitnik, N. Reul, and B. Chapron, “New Possibilities for Geophysical Parameter Retrievals Opened by GCOM-W1 AMSR2,” IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens., vol. PP, no. 99, pp. 1–14, 2015a.

E. Zabolotskikh, N. Reul and B. Chapron,  “Geophysical model function for the AMSR2 C- band wind excess emissivity at at high winds“, submitted to GRSL, 2015b.

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