简答题:根据下面资料，回答46-50题
"Nobody really knows" was Donald Trump's assessment of man-made global warming,in an interview on December 11th. As far as the atmosphere is concerned, that puts him at odds with most scientists who have studied the matter. They do know that the atmosphere is warming, and they also know by how much. But turn to the sea and Mr. Trump has a point. (46) Though the oceans are warming too, climatologists readily admit that they have only a rough idea how much heat is going into them, and how much is already there .
Many suspect that the heat capacity of seawater explains the climate pause of recent years, in which the rate of atmospheric warming has slowed. (47) But without decent data,it is hard to be sure to what extent the oceans are acting as a heat sink that damps the temperature rise humanity is visiting upon the planet—and, equally important, how long they can keep that up.
This state of affairs will change, though, if a project described by Robert Tyler and Terence Sabaka to a meeting of the American Geophysical Union, held in San Francisco this week, is successful. (48) Dr. Tyler and Dr. Sabaka, who work at the Goddard Space Flight Centre, in Maryland, observe that satellites can detect small changes in Earth's magnetic field induced by the movement of water. They also observe that the magnitude of such changes depends on the water's temperature all the way down to the ocean floor. That,they think, opens a window into the oceans which has, until now, been lacking. To measure things in the deep sea almost always requires placing instruments there—either by lowering them from a ship or by putting them on board submarine devices. (49) The supply of oceanographic research vessels, though, is limited, and even the addition in recent years of several thousand "Argo" probes (floating robots that roam the oceans and are capable of diving to a depth of 2,000 metres) still leaves ocean temperatures severely under-sampled .
All this means that, if you know where and how ocean water is displaced, the changes in the magnetic field, as seen from a satellite, will tell you the heat content of that water. (50)Dr. Tyler and Dr. Sabaka therefore built a computer model which tried this approach on one reasonably well-understood form of oceanic displacement, the twice-daily tidal movement caused by the gravitational attraction of the moon .
第（46）题答案_______