undef

s1a-iw-grd-vh-20171225t224529-20171225t224554-019865-021cd0-002_filter

s1a-iw-grd-vv-20171225t224529-20171225t224554-019865-021cd0-001_filter

s1a-iw-grd-vh-20171225t224529-20171225t224554-019865-021cd0-002_winddir

s1a-iw-grd-vv-20171225t224529-20171225t224554-019865-021cd0-001_winddir