全球变化过程的数学模拟和定量预测

本文首先介绍了全球变化过程数学模拟问题的由来、主要研究内容和重要意义,进一步讨论了全球变化过程综合模拟的数学模型及其已经取得的进展和系统分析的可能应用,然后介绍了过去全球变化过程的数学模拟以及已有的部分区域性工作基础和几种数学方法的可能应用。作者综述了GCM模型的应用现状和存在问题,并讨论了全球变化过程的定最预测,分析了若干新技术的可能应用,提出了对开展此项工作的看法和建议。

MATHEMATICAL SIMULATION AND QUANTITATIVE PREDICTION OF GLOBAL CHANGE PROCESS

General trend in natural sciences is the development from qualitative researches to quantitative ones. Generally, range and depth of quantitative researches reflect the level and degree of maturity of a discipline. Global change researches deal with the subiects of common interest and great importance. They are highly comprehensive, complicated and difficult problems and attract attention of scientists of the world. Specialists of various disciplines and research field are utilizing many new and advanced methods and means, including quantitative methods and mathematical simulation. In our opinion, quantitative researches of global change process may be divided into the following three parts: 1) mathematical simulation of present global change process; 2) mathematical simulation of past global change process; 3) quantitative prediction of global change processes. Each of the above- mentioned parts has its own characteristics in research subject and mathematical means. For the purpose of mathematical simulation of global change processes, an integrated model of Earth system is introduced and reviewed. The integrated Earth system model consists of many subsystems that couple the various parts of Earth system. For example, the following model can be given, such as models that couple the terrestrial ecosystems and the atmosphere, models that couple physics and chemistry in the atmosphere and models that couple the ocean and the atmosphere. In this paper system analysis is proposed as a mathematical tool for integrated modeling of the Earth system. According to one of the core projects of IGCP, the emphasized time interval, for past global change researches are from 2000a B. P. and 0.15Ma B. P. to present. Generally researches of past global change processes consist of studies in global scale and studies in regional scale and the mathematical models shall be constructed based on geological conceptual models. So that the conceptual model for the region within the territory of China may be set up based on the following regional materials and scientific research results obtained during the past years, such as: paleoclimate researches, glaciers researches, researches of relationship between circulation of monsoons and continent ice amount, comprehensive studies of Early and Middle Pleistocene paleoenviroment, studies of the relationship between main geological events at 2.50Ma B. P. and global change. In the above, we illustrate only part of the regional materials and scientific research results within the teritory of China which are suitable, for constructing geological conceptual models. Most of them can be regarded as source materials for building geological conceptual models. A few of them can be used as conceptual models directly, without any further processing and remoulding. We consider that the main mathematical models for simulation of past global change processes are general circulation models(GCMs). Besides, there are many other mathematical models being utilized in geosciences successfully and a number of them are available for modeling past global change processes. These mathematical models and methods can be shown as follows: (1) Time series analysis: Time series are sequences of observations which are arranged by their order of occurrence, either in time or along a spatial dimension. Many types of time series occur in global change processes, ranging from time series encountered in paleoclimate data, to data of fossil glaciers, to data of pollen and terrestrial fauna and to data of sequences such as measured loess sections and other stratigraphic sections. Consequently, time series analysis is a powerful tool for studies of past global change processes. (2) Spectral analysis and digital filtering: These two methods are widely used in most field of natural sciences and may be successfully used in simulation of past global change processes. (3) Simulation, by Markov processes: Markov processes are one kind of random processes and in their occurrence exibit an effect in which previous events influence the subsequent events. So that Markov processes may be applied for simulating transformation from one state of paleoenvironment to another. (4) Applications of Catastrophe theory: Catastrophe theory is a new branch of mathematics which is developed based on differential topology and may be used for simulating abrupt change in global scale. (5) Other mathematical models and methods, including multivariate analysis and so on. In this paper progress in application of GCMs for coupling key aspects of the Earth system is reviewed. Questions arising in coupling main subsystems of the Earth system are discussed. Necessity and possibility of quantitative prediction of global changes are discussed and two examples are illustrsted. For making ore bvious advances in this research field, four kinds of new techniques are recommended to be utilized. Finally, in concluding remarks, we have come to several important conclusions. Combination of regional conceptual models within the territory of China and mathematical models used in geosciences is the main idea of this paper. We have obtained abundant regional materials and scientific research results, including the research results of Chinese loess which attracted worldwide attention. Therefore, some new results with their own characteristics can be expected in the near future.