undef
s1a-iw-grd-vh-20170127t100054-20170127t100119-015016-018875-002_filter
s1a-iw-grd-vv-20170127t100054-20170127t100119-015016-018875-001_filter
s1a-iw-grd-vh-20170127t100054-20170127t100119-015016-018875-002_winddir
s1a-iw-grd-vv-20170127t100054-20170127t100119-015016-018875-001_winddir