M ULTI-FREQUENCY  MICROWAVE EMISSION OF THE EAST ANTARCTIC PLATEAU    IGARSS- Vancouver –  July 24-29 2011 Marco Brogioni ...
Outline <ul><li>Objectives and background </li></ul><ul><li>The Domex experiment </li></ul><ul><li>Satellite (SMOS- AMSR-E...
Objectives <ul><li>Verify the applicability of the East  Antarctic plateau  as an extended target  for calibrating and mon...
Dome C and the Antarctic Plateau <ul><li>T he site is view on a  sub-daily frequency  by polar-orbiting  satellites, at a ...
The Domex-2 experiment <ul><li>With a view to the launching of the ESA’s SMOS satellite, an experimental activity called  ...
The DOMEX Campaign Concordia base Air temperature Mean: - 53 degs Max:  - 23 degs Min:  - 78 degs TOWER VIEW
Complementary Snow measurements Winter Summer Snow layers: Temperature Hardness Density Grains shape and Size Dielectric C...
Domex -2 – 2009 campaign Theta = 42° SMOS angle Power Failure > 10 days Radomex Temperature < -60°C !!!  No temperature co...
Temporal Stability – corrected values 6 Months Scale  = December 2008 – May 2009
Domex-2 : 2010 campaign 11 months data Power Failure PC crash April 10 Problem Solved –July 2010
SMOS comparison  - Temporal Trends The target response is very stable. Fluctuation are typical of the SMOS data. Domex Tb ...
Possible Explaination: wind effect Lines= High Wind Speed (> 7 m/s)
DOMEX- Angular Trend
SMOS – comparison: Angular Trend SMOS data provided by CESBIO dots – SMOS lines - DOMEX
Multi-frequency Tb data: temporal trends Obs. angle 55 deg Mean Std Dev V pol H pol almost a Black Body V pol fluctuates l...
Tb – StdDev  vs Frequency (AMSR-E & DOMEX) Tb sdev decreases when frequency decreases The site is stable at L band
The electromagnetic model <ul><li>The snowpack is modeled as a  stack  of  n layers  with planar boundaries over a half-sp...
<ul><li>The  permittivity  of the layers is modeled by using the  SFT . </li></ul><ul><li>The  model is based on the wave ...
<ul><li>Comparison of temporal trends </li></ul>Model Results The model is able to estimate the e.m. data with a good accu...
<ul><li>Penetration depths </li></ul>Model Results Penetration Depth Frequency (GHz) Penetration depth (m) 1.4 165 6.8 22 ...
Conclusions <ul><li>The DOMEX-2 experiment started in November 2008 and ended in December 2010.  </li></ul><ul><li>The hig...
RADOMEX looking in the Antarctic night Thanks for the attention!
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TH1.T04.2_MULTI-FREQUENCY MICROWAVE EMISSION OF THE EAST ANTARCTIC PLATEAU_IGARSS_2011_DOMEX_presentation.ppt

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TH1.T04.2_MULTI-FREQUENCY MICROWAVE EMISSION OF THE EAST ANTARCTIC PLATEAU_IGARSS_2011_DOMEX_presentation.ppt

  1. 1. M ULTI-FREQUENCY MICROWAVE EMISSION OF THE EAST ANTARCTIC PLATEAU IGARSS- Vancouver – July 24-29 2011 Marco Brogioni G.Macelloni, S. Pettinato CNR-IFAC R. Zasso, A. Crepaz CVA-ARPAV B. Padovan, J. Zaccaria PNRA M. Drinkwater ESA-ESTEC
  2. 2. Outline <ul><li>Objectives and background </li></ul><ul><li>The Domex experiment </li></ul><ul><li>Satellite (SMOS- AMSR-E) and ground data </li></ul><ul><li>The e.m. model </li></ul><ul><li>Model comparison </li></ul><ul><li>Conclusions and Perspectives </li></ul>
  3. 3. Objectives <ul><li>Verify the applicability of the East Antarctic plateau as an extended target for calibrating and monitoring low frequency microwave radiometers using ground based (the Domex-2 experiment) and satellite data (SMOS) </li></ul><ul><li>Understanding the multi-frequency microwave emission of the Antarctic plateau by using satellite and ground data in combination to e.m. model </li></ul>
  4. 4. Dome C and the Antarctic Plateau <ul><li>T he site is view on a sub-daily frequency by polar-orbiting satellites, at a variety of incidence and azimuth angles. </li></ul><ul><li>Homogeneity of snow surface at the 100 km scale . </li></ul><ul><li>Small surface roughness relative to other ice sheets. </li></ul><ul><li>Low snow accumulation rate (around 3.7cm/yr). </li></ul><ul><li>Clear sky , and extremely dry and stable atmosphere. </li></ul><ul><li>Well known topography and environmental condition </li></ul>Concordia Station (Dome C): 75.125 S, 123.25 E 3270 a.s.l Dome C © CSA
  5. 5. The Domex-2 experiment <ul><li>With a view to the launching of the ESA’s SMOS satellite, an experimental activity called DOMEX , supported by ESA and PNRA, was started at Dome-C, Antarctica in 2005 with a first pilot project (Domex-I, duration one month) and continue with Domex-2 . </li></ul><ul><li>The main scientific objective is to demonstrate the stability of the site in order to provide L-band microwave data for SMOS calibration. </li></ul><ul><li>DOMEX-2 experiment consisted in an L-band and an infrared (8-14 µm) radiometers (RADOMEX) installed at Concordia base on an observation tower at a height of 15 m respect to the ice sheet. Data were collected continuously (24/24 h) over two entire Austral annual cycle, starting from December 2008. Snow measurements (including snow stratigraphy, density, grains size and shape, temperature) and meteorological data, were also collected during the experiment. </li></ul>
  6. 6. The DOMEX Campaign Concordia base Air temperature Mean: - 53 degs Max: - 23 degs Min: - 78 degs TOWER VIEW
  7. 7. Complementary Snow measurements Winter Summer Snow layers: Temperature Hardness Density Grains shape and Size Dielectric Constant Snow deposition: Grains shape and Size Classification(precipitation, hoar,wind, etc.)
  8. 8. Domex -2 – 2009 campaign Theta = 42° SMOS angle Power Failure > 10 days Radomex Temperature < -60°C !!! No temperature control  Low temperature /High fluctuation
  9. 9. Temporal Stability – corrected values 6 Months Scale = December 2008 – May 2009
  10. 10. Domex-2 : 2010 campaign 11 months data Power Failure PC crash April 10 Problem Solved –July 2010
  11. 11. SMOS comparison - Temporal Trends The target response is very stable. Fluctuation are typical of the SMOS data. Domex Tb could be used as a benchmark for improve SMOS data? some jumps: surface effect (?)
  12. 12. Possible Explaination: wind effect Lines= High Wind Speed (> 7 m/s)
  13. 13. DOMEX- Angular Trend
  14. 14. SMOS – comparison: Angular Trend SMOS data provided by CESBIO dots – SMOS lines - DOMEX
  15. 15. Multi-frequency Tb data: temporal trends Obs. angle 55 deg Mean Std Dev V pol H pol almost a Black Body V pol fluctuates less because of the Brewster angle! L C X Ku Ka 175 153.16 152.84 154.70 150.36 - 1.15 1.29 1.65 2.12 L C X Ku Ka 218 200.23 194.93 184.83 169.88 - 0.50 0.57 0.81 1.80
  16. 16. Tb – StdDev vs Frequency (AMSR-E & DOMEX) Tb sdev decreases when frequency decreases The site is stable at L band
  17. 17. The electromagnetic model <ul><li>The snowpack is modeled as a stack of n layers with planar boundaries over a half-space medium. </li></ul><ul><li>Each layer is characterize by: </li></ul><ul><ul><li>temperature T l , </li></ul></ul><ul><ul><li>grain radius r l , </li></ul></ul><ul><ul><li>depth d l , </li></ul></ul><ul><ul><li>density  l , </li></ul></ul><ul><ul><li>fractional volume f l , </li></ul></ul><ul><ul><li>permittivity  eff l . </li></ul></ul><ul><li>All the parameters used in the model are derived from Dome C snowpack measurements (EPICA, Drinkwater et al.,2003). </li></ul>d 1 d 2 d 3 d n-1 d n d 0  i z . . . n layers Half-space
  18. 18. <ul><li>The permittivity of the layers is modeled by using the SFT . </li></ul><ul><li>The model is based on the wave approach which accounted for the reflection and transmission between the layers by means of the propagating matrix (Kong,1990). </li></ul><ul><li>The vertical and horizontal brightness temperatures are expressed by adding the contributions of the snow layers by means of the fluctuation dissipation theorem (Jin,1984). </li></ul>The electromagnetic model
  19. 19. <ul><li>Comparison of temporal trends </li></ul>Model Results The model is able to estimate the e.m. data with a good accuracy Some discrepancy are present at Ku- and Ka-band 37 GHz 19 GHz 10 GHz 6.8 GHz 1.4 GHz
  20. 20. <ul><li>Penetration depths </li></ul>Model Results Penetration Depth Frequency (GHz) Penetration depth (m) 1.4 165 6.8 22 10 12 19 3.5 37 1.5
  21. 21. Conclusions <ul><li>The DOMEX-2 experiment started in November 2008 and ended in December 2010. </li></ul><ul><li>The high temporal stability of Tb at V polarization is confirmed in both 2009 and 2010. Tb at H polarization exhibits a high fluctuation due to the surface and sub-surface effect (as expected). </li></ul><ul><li>The angular and temporal trends exhibit a very good agreement with SMOS data </li></ul><ul><li>Multi-frequency data emphasize the mechanisms that dominate the emission of the ice sheet </li></ul><ul><li>A e.m. was developed and validated using satellite and ground data </li></ul><ul><li>The e.m. is able to explain the jumps observed in H pol. data </li></ul>
  22. 22. RADOMEX looking in the Antarctic night Thanks for the attention!

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