A preliminary evaluation of streamline analysis

Duty forecasters at each of six tropical stations, drew a series of ten 5000 ft streamline patterns at 12 hourly intervals commencing at 1600 GMT on 20 May, 1956. Each of these charts has been compared with the corresponding chart drawn by an analyst of Central Analysis Section, and some attempt made to assess the feasibility of drawing 5000 ft streamlines with reasonable objectivity with the net-work limitations of the Australian and adjacent Asiatic regions. Salient features on each of the ten charts are discussed, and some general remarks on the Bjerknes-Sandstrom technique for representing air flow are included. It is concluded that the wind network at 5000 ft is sufficient for a reasonable presentation of streamline patterns, although there are serious deficiencies away from the mainland. Subjectivity in drawing of patterns, though initially high, tends to decrease as experience in the technique is gained. Further investigation into stream-line techniques is worthwhile.