spase://CNES/NumericalData/CDPP-Archive/ISEE1/SND/ISEE1_SND_H2

This data set contains reconstructed calibrated wave spectra and the ancillary parameters necessary for their interpretation from the ISEE1 SND H2 resonance sounder instrument. Each record has a fixed content of 128 frequency steps and key ancillary parameters. Each frequency step has 7 samples. Depending on the mode, the full frequency range can extend from 0.3 to 51 kHz or 0-353 kHz. The actual frequency range can be reduced with respect to these values. In that case the missing steps are set to 0. Each valid frequency step can have less than 7 samples recorded with increasing time. The missing ones are set to 0. In some specific modes where there are more than 7 samples per step, the first one is the strongest value observed during the step analysis. The last one is the lowest value, the 5 other values are the averages of remaining samples as time increases. Record content is identical for both resonance spectra (active mode emitter on) and natural plasma waves (passive mode, emitter off). Note: In the 3200 Hz mode, for technical reason induced by the instrument design, frequency used from step 0 to 15 are the same than those used from steps 31 to 16 (namely from 3200 to 48000 Hz by 3200 Hz step). This introduces an 'artefact' (a pseudo mirror mode) when you try to plot the data (especially spectrograms). Thus, we decided to avoid plotting data issued from steps 0 to 15 for the 3200 Hz mode in the spectrograms distribued by CDPP. However, in CDPP/CDF files, data are preserved as originally acquired by the instrument.