1 / 13

Cutting-edge Radiometer Concepts for Wet Path Delay Estimation

Explore innovative radiometer concepts to enhance wet path delay estimation in coastal and inland areas. Learn about different types of land contamination and corrective measures. Discover technical options and potential improvements for accurate estimations.

mmarshall
Download Presentation

Cutting-edge Radiometer Concepts for Wet Path Delay Estimation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Radiometer Concepts for Coastal and Inland Wet Path Delay Estimation Shannon Brown Jet Propulsion Laboratory Shannon.T.Brown@jpl.nasa.gov

  2. Radiometer Land Contamination • Land contamination can be divided into three categories • Far sidelobe contamination • Near sidelobe contamination • Main beam contamination Far sidelobes Far sidelobe contamination Correctable to acceptable levels (~ 1mm) Near sidelobe contamination More difficult, but correction is possible (~2-4 mm) Main beam contamination Very difficult to correct (20-40 mm) Mainbeam Near sidelobes

  3. Main Beam Contamination • Along track averaging can improve coastal approach for preferred land/ground track orientations • Additional improvements may be made through correction algorithms based on pattern weighted main beam land fractions ~20 km approach estimated for worst case for AMR 10 km approach at Harvest estimated for AMR

  4. Radiometer Concepts • Option 1: Maintain traditional channel set, but increase antenna dimensions • Real aperture • Synthetic aperture • > 2.5 m aperture required for < 5 km resolution

  5. Option 1 NASA Aquarius Heritage for 2.5 m reflector Lightweight Rainfall Radiometer – aircraft heritage for synthetic aperture radiometer technology Visible Camera LRR

  6. Radiometer Concepts • Option 1: Maintain traditional channel set, but increase antenna dimensions • Real aperture • Synthetic aperture • > 2.5 m aperture required for < 5 km resolution • Pros: • Proven retrieval algorithm • Retrievals in all non-precipitating conditions • High sensitivity to PD over the range of PDs • Cons: • Complications from large real aperture required • Synthetic aperture technique proven in aircraft demonstration, but not yet in space • Difficult to get PD in inland areas (i.e. rivers)

  7. 22.235 GHz (H2O) 118 GHz (O2) 55-60 GHz (O2) 183.31 GHz (H2O) Move to Higher Frequency • Maintain 18-34 GHz channel set for open ocean retrievals • Maintain AMR heritage 1m reflector • Option 2: Include 1-2 higher frequency window channels for coastal PD extrapolation • Option 3: Include temperature and vapor sounding channels for PD retrievals over land and ocean

  8. Option 2 • Add 1 or 2 channels between 90-150 GHz to improve the extrapolation of PD from the last uncontaminated ocean pixel to the coast

  9. Option 2 Modeled Brightness Temperature to PD and CLW • 90 GHz TB ~8x more sensitive to CLW than 23.8 GHz TB • Sensitivity to high PD decreases with frequency 23.8 GHz 90 GHz 2.6 km 10 km dTB/dPD 130 GHz 160 GHz 2.1 km 1.5 km

  10. Option 2 • Add 1 or 2 channels between 90-150 GHz to improve the extrapolation of PD from the last uncontaminated ocean pixel to the coast • Pros: • Relatively small perturbation to add two channels in this frequency range • These channels will have < 5 km resolution with 1 m reflector • Cons: • These channels will loose sensitivity to PD for high PD values • Performance can be affected in variable cloud conditions near coast • Not likely to be able to get PD in inland areas (i.e. rivers)

  11. 183 + 1 183 + 3 183 + 7 166 Option 3 • Add temperature and water vapor sounding channels to retrieve PD over land and coast (channels near 50 or 118 GHz and channels near 183 GHz) • Will likely need 2-3 temperature sounding channels and 4 water vapor sounding channels 60 GHz Temperature Weighting Functions 183 GHz Water Vapor Weighting Functions Height (km)

  12. Option 3 • Add temperature and water vapor sounding channels to retrieve PD over land and coast (channels near 50 or 118 GHz and channels near 183 GHz) • Pros: • Should be able to retrieve PD over land or water • High resolution < 5 km • Cons: • Reduced accuracy in clouds • Reduced sensitivity to PD in moist conditions • Uncertain with what accuracy this can be done

  13. Conclusions • Option 1: Large antenna • Scientific Risk: Low • Engineering Risk: Medium • Option 2: Higher frequency window channels • Scientific Risk: Medium • Engineering Risk: Low • Option 3: Temperature and water vapor sounding channels • Scientific Risk: Medium • Engineering Risk: Medium

More Related