Metocean Comparisons of Jason-2 and AltiKa—A Method to Develop a New Wind Speed Algorithm

Quartly, GD 2015 Metocean Comparisons of Jason-2 and AltiKa—A Method to Develop a New Wind Speed Algorithm. Marine Geodesy, 38 (S1). 437-448.

MarGeod_Quartly2015_AM.pdf - Accepted Version
Available under License Creative Commons Attribution Non-commercial.

Download (1MB) | Preview
Official URL:


As well as range, the AltiKa altimeter provides estimates of wave height, Hs and normalized backscatter, s0, that need to be assessed prior to statistics based on them being included in climate databases. An analysis of crossovers with the Jason-2 altimeter shows AltiKa Hs values to be biased high by only »0.05m, with a standard deviation (s.d.) of »0.1m for seven-point averages. AltiKa’s s 0 values are 2.5–3 dB less than those from Jason-2, with a s.d. of »0.3 dB, with these relatively large mismatches to be expected as AltiKa measures a different part of the spectrum of sea surface roughness. A new wind speed algorithm is developed through matchinghistogram of s0 values to that for Jason-2 wind speeds. The algorithm is robust to the use of short durations of data, with a consistency at roughly the 0.1 m/s level. Incorporation of Hs as a secondary input reduces the assessed error at crossovers from 0.82 m/s to 0.71 m/s. A comparison across all altimeter frequencies used to date demonstrates that the lowest wind speeds preferentially develop the shortest scales of roughness.

Item Type: Publication - Article
Additional Information. Not used in RCUK Gateway to Research.: his is an Accepted Manuscript of an article published by Taylor & Francis in Marine Geodesy on 9 October 2015, available online:
Additional Keywords: AltiKa altimeter, Ka-band, sigma0, wind speed, wave height, histograms
Subjects: Earth Observation - Remote Sensing
Meteorology and Climatology
Divisions: Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: Graham Quartly
Date made live: 11 Nov 2015 10:37
Last Modified: 25 Apr 2020 09:57

Actions (login required)

View Item View Item