Radar Baak-Soatter from the Sea Surface 



the signal phase (or phase cosine), which is nonllnearly related to 

 the complex signal amplitude. More detailed Investigations using 

 longer time series are needed to decide whether the ocean wave 

 spectrum can be extracted from the Doppler spectrum of long range 

 HF sea echo in the presence of unavoidable ionospheric noise. 



ACKNOWLEDGMENT 



This work was supported in part by the Office of Naval 

 Research under Contract No. ONR NOOOl 4-69-C-0057. 



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