FN Archimer Export Format PT J TI Validation of AltiKa Matching Pursuit Rain Flag BT AF TOURNADRE, Jean POISSON, J. C. STEUNOU, N. PICARD, B. AS 1:1;2:2;3:3;4:2; FF 1:PDG-ODE-LOS;2:;3:;4:; C1 IFREMER, Lab Oceanog Spatiale, F-29280 Plouzane, France. Space Oceanog Div, Collecte Localisat Satellite, St Agne, France. Ctr Natl Etud Spatiales, F-31055 Toulouse, France. C2 IFREMER, FRANCE CLS, FRANCE CNES, FRANCE SI BREST SE PDG-ODE-LOS UM LOPS IN WOS Ifremer jusqu'en 2018 copubli-france IF 0.979 TC 7 UR https://archimer.ifremer.fr/doc/00286/39674/41519.pdf LA English DT Article AB The major drawback of Ka band, operating frequency of the AltiKa altimeter on board SARAL, is its sensitivity to atmospheric liquid water. Even light rain or heavy clouds can strongly attenuate the signal and distort the signal leading to erroneous geophysical parameters estimates. A good detection of the samples affected by atmospheric liquid water is crucial. As AltiKa operates at a single frequency, a new technique based on the detection by a Matching Pursuit algorithm of short scale variations of the slope of the echo waveform plateau has been developed and implemented prelaunch in the ground segment. As the parameterization of the detection algorithm was defined using Jason-1 data, the parameters were re-estimated during the cal-val phase, during which the algorithm was also updated. The measured sensor signal-to-noise ratio is significantly better than planned, the data loss due to attenuation by rain is significantly smaller than expected (<0.1%). For cycles 2 to 9, the flag detects about 9% of 1Hz data, 5.5% as rainy and 3.5 % as backscatter bloom (or sigma0 bloom). The results of the flagging process are compared to independent rain data from microwave radiometers to evaluate its performances in term of detection and false alarms. PY 2015 PD SEP SO Marine Geodesy SN 0149-0419 PU Taylor & Francis Inc VL 38 IS Suppl.1 UT 000362123500008 BP 107 EP 123 DI 10.1080/01490419.2014.1001048 ID 39674 ER EF