Skip to main content
Article thumbnail
Location of Repository

Jason-1/Jason-2 metocean comparisons and monitoring

By Graham D. Quartly

Abstract

The initial tandem phase of the Jason-2 mission is important for the calibration of the entire altimetric system, not just the records of sea surface height. However, as well as allowing a bulk comparison of metocean parameters such as wave height and backscatter strength (used to infer wind speed), it affords a more detailed opportunity to understand the artefacts within each instrument. The wave height comparison shows no bias between the instruments, with the mismatch error of consecutive points independent of one another. The backscatter difference is not a simple offset, but has a trend with weak non-linear variations. The technique for backscatter monitoring using Ku-/C-band differences is validated during the tandem phase, and extended to show ~59-day oscillations throughout the Jason-1 mission. This effect, which is predominantly in the C-band, is related to changing solar exposure, due to the fraction of orbit in eclipse varying as the orbit precesses. Such anomalies were partially present in TOPEX-B data, but are not noticeable for Jason-2. It is recommended that all TOPEX, Jason-1 and Jason-2 data be transformed to a consistent scale, allowing for the bias and trend terms in the offsets between instruments, and correcting for any long-period drifts in individual calibration; this will enable a single wind speed algorithm to be applied to the combined satellite data

Topics: GC
Year: 2010
OAI identifier: oai:eprints.soton.ac.uk:142025
Provided by: e-Prints Soton

Suggested articles

Citations

  1. (2007). A new approach to estimation of global air-sea gas transfer velocity fields using dual frequency altimeter backscatter. doi
  2. (2008). A parametric model for ocean wave period from Ku band altimeter data. doi
  3. (2001). Analyzing altimeter artefacts: statistical properties of ocean waveforms. doi
  4. (2006). Combined wind vector and sea state impact on ocean nadir-viewing Ku- and C-band radar cross-sections. doi
  5. (1998). Estimation of wind stress using dualfrequency TOPEX data. doi
  6. (1999). Global precipitation statistics from dual-frequency TOPEX altimetry. doi
  7. (2006). Improved level-3 oceanic rainfall retrieval from dual-frequency spaceborne radar altimeter systems. doi
  8. (2009). Improving the altimetric rain record from doi
  9. (2009). Improving the intercalibration of σ 0 values for the Jason-1 and Jason-2 altimeters. doi
  10. (2004). Improving the Jason-1 ground tracking to better account for attitude effects. doi
  11. (2000). Monitoring and cross-calibration of altimeter σ 0 through dual-frequency backscatter measurements. doi
  12. (2009). Optimizing σ 0 information from the Jason-2 altimeter. doi
  13. (1980). Radar altimeter mean return waveforms from near-normal incidence ocean surface scattering. doi
  14. (2004). Sea state and rain: A second take on dual-frequency altimetry. doi
  15. (1977). The average impulse response of a rough surface and its applications. doi
  16. (2004). Validation of Jason and Envisat altimeter dual-frequency rain flags. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.