天然气水合物与全球变化研究

天然气水合物含碳量超过全球所有其他来源有机碳的总和,是地圈浅部的极重要碳库。自然界中温压条件的微小变化都会引起天然气水合物的形成或分解,从而吸收或释放甲烷,对全球碳循环和温室效应产生重要影响。天然气水合物对全球气候变化、冰期和间冰期的交替的反馈在极地和中低纬度不同,在中低纬度
也有两种相反的过程,因而对其总效应的方向和强度尚需详细研究和估计。我国许多海区有天然气水合物存在的条件,在南海已有报道;可通过地震剖面的重新判读及数值模拟估计天然气水合物的储藏量和它对海平面变化的反馈,以提供边缘海这类研究的范例。

THE STUDY OF GAS HYDRATES AND ITS RELATION WITH GLOBAL CHANGES

Gas hydrates contains a large quantity of organic carbon which exceeds the total organic carbon from other sources. It is an important carbon reservoir in shallow geosphere. A slight variation of temperature/pressure would cause the formation/decomposition of gas hydrates,and subsequent consumption/release of methane. This exerts significant influence on global carbon cycle and greenhouse effect. The Polar regions differ from the mediate low latitudes on the feedback of gas hydrates to global climate change and galcial/interglacial alternation. Even in mediate low latitudes there exist two processes of opposite directions. The total effect of gas hydrates on global changes needs to be estimated in further researches. In China seas, there exist T P conditions suitable for the occurrence of gas hydrates. The BSR as an indication of gas hydrates has been reported in southern South China Sea. The total reserves of gas hydrates and their feedback to sea level changes in China seas may be assessed based on careful re interpretation of seismic profiles and computer simulations. This may provide an example for the marginal seas.