Internal wave signature has been identified in multiple series of SAR (Synthetic Aperture Radar) ERS-1 & ERS-2 images over the Malin continental slope / shelf break area, offshore West Scotland. The satellite data cover three different years from 1993 to 1995 and there are mainly from summer and autumn season. A statistical analysis has been performed in order to examine the spatial and temporal variability of the internal wave appearance with respect to their properties such as wavelength, form and type of surface modulation. We found that no internal waves were present on the images for wind speeds exceeding 11 m/s during summer/early autumn months when internal waves are known to be present in the area. In addition to this, we notice that slicks were visible on the images for winds < 6 m/s. The majority of the observed internal waves is in the form of solitary internal wave (i.e. non-linear internal wave with its wavelength and amplitude decreasing from the front to the rear of the wave), they travel across slope towards the shore and they seem to be tidally generated. However, in images of wind speeds < 6 m/s another type of internal waves has been identified which they propagate along slope, are slick modulated and they are, in contrast to the across slope solitary waves, of linear wavelength and do not seem to have tidal dependence. Previous theoretical and laboratory work combined with in situ measurements can provide explanation for the generation and properties of these waves. In conclusion, we argue that the wind field can not only bias whether internal waves can be observed on SAR imagery but also can be a crucial factor for identification of internal waves related to entirely different generation mechanisms.

Emmanouil K. Oikonomou

20/11/96

Jennifer Fyall

ESRIN

Via Galileo Galilei

C. P. 64, 00044 Frascati

Italy

Dear J. Fyall,

I am sending you the abstract of our paper titled "The effect of wind field in observing Internal Wave phenomena over the continental slope on SAR ERS-1 & ERS-2 satellite imagery" for the 3rd ERS Symposium to be held in Florence from 18-21 March 1997 with possible presenter, in case of acceptance, myself.

I would appreciate if you could consider our paper for presentation in the above Symposium.

I am looking forward to hearing from you.

Sincerely yours,

Emmanouil K. Oikonomou

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry