undef
s1a-ew-grd-vh-20160926t093452-20160926t093552-013222-01509c-002_filter
s1a-ew-grd-vv-20160926t093452-20160926t093552-013222-01509c-001_filter
s1a-ew-grd-vh-20160926t093452-20160926t093552-013222-01509c-002_winddir
s1a-ew-grd-vv-20160926t093452-20160926t093552-013222-01509c-001_winddir