CREATE TABLE table_name_37 (purpose VARCHAR(255), yield VARCHAR(255), location VARCHAR(255), elevation_ VARCHAR(255), _height VARCHAR(255))
Which Purpose has an Elevation + Height of 0 + metres (ft), a Location of bikini, namu (charlie), and a Yield of 220 kt?
    
SQL: SELECT purpose FROM table_name_37 WHERE elevation_ + _height = "0 + metres (ft)" AND location = "bikini, namu (charlie)" AND yield = "220 kt"