TOULOUSE, France: Hours after Malaysian Air Flight 370 vanished on March 8, Inmarsat pulled together a team of engineers thousands of miles away at its London headquarters for a marathon data-crunching session to help find the missing jet.

Their mission: Piecing together the few signals picked up by an Inmarsat satellite to direct the search effort, which in the initial phase focused on the Boeing 777’s flight path from Kuala Lumpur to Beijing. After a week of study, the data revealed two plausible, if surprising, trajectories — one heading north into central Asia and one south toward Antarctica.

The breakthrough, which helped dramatically narrow the search corridor, was based on research using the so-called Doppler effect named after 19th-century Austrian physicist Christian Doppler. After establishing a broad flight path, the team hunkered down to pinpoint a more accurate possible crash site.

Meanwhile, China demanded that Malaysia turn over the satellite data used to conclude that the jetliner had crashed. Officials sharply narrowed the search area as a result of that assessment, but the zone remains as large as Texas and Oklahoma combined.

Australia said improved weather would allow the hunt for the plane to resume Wednesday after gale-force winds and heavy rain forced a daylong delay. “We’re not searching for a needle in a haystack — we’re still trying to define where the haystack is,” Australia’s deputy defense chief, Mark Binskin, said.