undef

s1b-ew-grd-hv-20170526t084727-20170526t084832-005767-00a1b4-002_filter

s1b-ew-grd-hh-20170526t084727-20170526t084832-005767-00a1b4-001_filter

s1b-ew-grd-hh-20170526t084727-20170526t084832-005767-00a1b4-001_winddir

s1b-ew-grd-hv-20170526t084727-20170526t084832-005767-00a1b4-002_winddir