2006年职称英语模拟题卫生B第二套及答案

4 Hansen found soots effect on snow albedo （solar energy reflected back to space）， which may be contributing to trends toward early springs in the Northern Hemisphere， such as thinning Arctic sea ice， melting glaciers and permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.

5 "Black carbon reduces the amount of energy reflected by snow back into space， thus heating the snow surface more than if there were no black carbon，" Hansen said. Soots increased absorption of solar energy is especially effective in warming the worlds climate. "This forcing is unusually effective， causing twice as much global warming as a carbon dioxide forcing of the same magnitude，" Hansen noted.

6 Hansen cautioned， "although the role of soot in altering global climate is substantial， it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century. Such gases are expected to be the largest climate forcing the rest of this century.

7 The researchers found that observed warming in the Northern Hemisphere was 1arge in the winter and spring at middle and high latitudes. These observations were consistent with the researchers climate model simulations， which showed some of the largest warming effects occurred when there were heavy snow cover and sufficent sunlight.

词汇：

soot n. 煤烟， 煤灰

emission n. 释放， 散发， 排放

simulation v. 模拟

latitude n. 纬度