新生代增温情景下自然火历史的研究

自然火是地球系统的重要组成部分,与气候、植被关系紧密。全球增温情景下,自然火的演化规律和控制因素已经成为学术界的研究热点,通过整理分析自然火实际监测记录、模型模拟结果以及古记录反映的自然火历史,发现还存在一些亟待解决的问题:全球不同增温情景下自然火增多还是减少?其控制因素如何改变?本文选取距今最近的地质历史时期新生代中的典型增温期"中中新世气候适宜期"和"全新世大暖期",对其自然火研究进行分析总结,归纳得出温度是增温情景下自然火的重要控制因素,但是不同地区自然火控制因素有所不同,雨热条件的季节分配、植被类型的演替、雷电和火山活动等因素也对自然火有重要影响。季风区气候变幅大、植被类型丰富,其自然火演化及控制因素具有复杂性,是自然火研究的重要区域,建议在今后研究中,在东亚季风区选择涵盖未来百年可能增温幅度的理想沉积记录,对其记录的自然火历史、增温幅度、植被演替进行系统研究,进而探讨未来增温情景下自然火的演化规律和控制因素。

THE NATURAL FIRE HISTORY DURING WARMING PERIODS OF CENOZOIC

Natural fire is an important part of the earth system, and it has close relationship with climate and vegetation. In global warming scenario, the evolution law and control factors of natural fire have become a research hotspot in academia. Through analyzing the existing natural fire actual monitoring records, model simulation results, and natural fire history reflected by sedimentary records, we find some problems that need to be solved urgently:In global warming scenario, is the natural fire increasing or decreasing?How is the change of natural fire controlling factors?This paper selects the mid-Miocene Climatic Optimum and Holocene Thermal Maximum which are the typical global warming periods in the Cenozoic, and summarizes the natural fire researches in the world. It is concluded that temperature is the main controlling factor of natural fire, however, natural fire control factors vary in different regions that the seasonal distribution of rain and heat conditions, the vegetation types, lightning and volcanic activity also have important impact on the natural fire in the warming scenario. The monsoon region has variable climate and rich vegetation types. It is an important area for natural fire research that its natural fire evolution and control factors are complex. It is suggested that the ideal sedimentary record in the East Asian monsoon region can be selected to cover the possible range of temperature increase in the next 100 years. We can systematically study the natural fire history, temperature increase range and vegetation succession, and then explores the evolution law and control factors of natural fire under the future warming scenario.