undef

s1a-iw-grd-vv-20160917t100044-20160917t100109-013091-014c55-001_filter

s1a-iw-grd-vh-20160917t100044-20160917t100109-013091-014c55-002_filter

s1a-iw-grd-vv-20160917t100044-20160917t100109-013091-014c55-001_winddir

s1a-iw-grd-vh-20160917t100044-20160917t100109-013091-014c55-002_winddir