Traditional Culture Encyclopedia - Weather inquiry - What are the main methods to study climate change at present? Be specific if you can ~ thank you
What are the main methods to study climate change at present? Be specific if you can ~ thank you
3. 1 Laboratory and field observation and experimental research
In order to carry out experimental research, various experimental simulation devices and technologies have been established and developed, including biological genetic control technology, environmental control devices and technologies, open-top climate chamber, natural CO2 field and so on. , has developed rapidly in recent years (Liu et al., 1996). With the help of these devices, we can study the physiological and growth changes of plants or crops in the artificial simulated atmospheric environment with increased CO2, or conduct experiments or observations in the laboratory or in the field under certain control conditions to study population growth and competition, community structure and productivity, and even ecosystem functions. For example, the ecological, physiological, biochemical and morphological changes of plants were studied in an open-top culture room with doubled CO2 concentration, and the response mechanism of plants to doubled CO2 was analyzed.
In order to carry out field experimental research, various field observation techniques have been developed, such as using infrared analysis, configuring additional gas channels and circuit systems, and simultaneously observing farmland microclimate and crop growth and development (in Hu Ning, etc., 1993, in Hu Ning, 1993). A method for measuring greenhouse gas emission flux in soil-vegetation system was established. The greenhouse gas emission flux and diffusion law of typical terrestrial ecosystems (including farmland, forest and grassland) in China were observed in the field for a long time, and the CO2 flux was observed in detail. In order to explore the direct impact of elevated CO2 concentration on crop productivity, CO2 gas was released during the vigorous growth period of winter wheat and summer maize in farmland with different fertility, so as to keep the air CO2 concentration in the canopy of the affected population doubled. Using infrared CO2 analysis system to monitor CO2 concentration, a CO2 release system was established to regulate CO2 concentration in the experimental area, and the effects of crop growth and yield were observed. In addition, in order to understand the response of ecosystem or life zone to the change of CO2 concentration, in recent years, many units have also carried out remote sensing observation in different bands and are establishing a CO2 monitoring network.
3.2 Model research
In recent years, the research on numerical simulation and prediction by computer has developed rapidly, which provides the most scientific, effective and ideal method for quantitative study of climate change and its impact. At present, the models for studying the response of agriculture, forestry, water resources or natural ecosystems to global climate change can be summarized as static or empirical statistical models and dynamic or process models. ?
3.2. 1 empirical statistical model
The model is a mathematical model based on the non-dynamic experience or statistical relationship between climate and exposed units such as vegetation, crops and water resources. In order to study the impact on the affected units, it is necessary to select and compare the current and future climate, environment and socio-economic benchmarks. Among them, there are three ways to choose future climate scenarios or scenarios. One is to synthesize ideas and give a unified assumption of future warming (such as 1.0℃-4.0℃) or precipitation changes, which is the simplest or somewhat subjective way; The second way is the concept of similarity (including time and space); The third way is the concept of global circulation (including equilibrium and transient) model, which is the only reliable tool to simulate the global climate physical process at present. However, due to many uncertainties in the model, the simulation or prediction results of various models are still very different, and of course the results are bound to be very different. So this way can only be said to be a very promising way. In China, the early research mostly used the method of comprehensive conception. In recent years, many systematic achievements have been made by using the advantages and characteristics of China's historical climate and adopting similar conception methods and the conception methods of global circulation or regional climate balance model. In addition, empirical statistical models of various exposed units or occupations such as vegetation, agriculture, forestry and water resources have developed rapidly. In the aspect of ecological environment, Zhang Xinshi, Zhou Guangsheng and others (1993) introduced Holdridge life zone model to study the vegetation evolution trend in China and Qinghai-Tibet Plateau under the future climate conditions with the method of comprehensive conception. At the same time, the primary productivity model of vegetation was established (Zhou Guangsheng et al., 1995). With the support of GIS, Chen Yufeng and Li Kerang (1996) established a climate-vegetation response model in China with nine comprehensive climate parameters and soil as the limiting factor of climate-vegetation response relationship, which improved the model accuracy. At the same time, the influence on the area, horizontal and vertical distribution of main vegetation types in China was studied by using the estimated values provided by the conception method of global environmental balance model. ?
In agriculture, many scientists in China have studied the impacts of climate change on crops and agriculture by using comprehensive conceptual methods and various crop models. In recent years, Linda et al. (1996) developed the China stochastic weather simulation model, which can generate the daily maximum and minimum temperatures, solar radiation and precipitation under the climate scenarios required by crop models and main grassland models according to the annual, seasonal or monthly values provided by GCMs, so as to study the impact of global climate change on the future production of major crops and livestock in China. ?
In forestry, Xu Deying, Liu, Guo Quanshui and others (1997) studied the influence of climate change on the main afforestation tree species and forest productivity in China by constructing an eco-climate information database of the geographical distribution of various tree species and applying the software of eco-information system and the correlation model between forest productivity and climate and environmental variables. ?
In terms of water resources, Liu Chunyu et al. (1997) have developed three different random weather models, watershed hydrological models with different climatic zones and comprehensive evaluation models of water resources supply and demand, and evaluated the impact of climate change on hydrological and water resources in the main basins of China by using seven future climate scenarios output by balanced GCMs.
procedure schema
Process or dynamic model refers to the dynamics of interaction between climate and exposure unit based on process and using established physical laws and theories. Many subtle factors are considered in the process model. Generally speaking, the process model is more reliable than the empirical-statistical model for impact and prediction research. However, the main problem is that the input data needed to test the model or simulate the future impact is very high. At present, the process model is limited to some small spatial points and needs to be developed to a larger scope or region. In China, many process or dynamic models have been introduced or developed, and preliminary results have been achieved. ?
CERES and SPUR gap dynamic models are effective tools to analyze the sensitivity of forest communities to climate change, which can reveal the changes and succession of forest community organization and biomass in the process of climate change. The model considers the effects of light, temperature and water on the growth of trees, including the whole process from seed germination, growth to death (Chen Yufeng, Li Kerang, 1996). Gap model has reasonable mechanism, flexible structure modification, easy parameter estimation and diversified output. The results of gap dynamic simulation can be used to reveal the long and complex dynamic process of forest ecosystem, to test the influence of artificial drying on forest structure and its changes, and to test the theory or hypothesis of forest succession (Shao Guofan et al., 1995. ) In China, Yan Xiaodong and Zhao Shidong (1995) successively established the gap model of Changbai Mountain, Shao Guofan and Zhao Shidong (1995) and Wu and Deng Huiping (1996) established the gap model of northeast broad-leaved Korean pine forest, Chen Yufeng and Li Kerang.
Xiang Bin et al. (1996) studied the physiological and ecological changes of photosynthesis, transpiration, stomatal conductance and water use efficiency of alfalfa under CO2 doubling, and based on this, studied the physiological and ecological process model of alfalfa. Xiao Xiangming et al. (1996) used the century ecosystem process model to simulate the biomass dynamics of grassland in Inner Mongolia at 1980- 1989, and estimated the effects of phenological changes and CO2 multiplication on the primary productivity of typical grassland and soil organic matter content. Gao Qiong et al. (1996) used the spatial simulation method to simulate the landscape dynamics of alkaline grassland in Songnen Plain of Northeast China. Under the current climate conditions, the output results of the model are very consistent with the distribution dynamics of class blocks observed in Ihm2 plot 1989- 1993. ?
Pan Xuebiao et al. (1996) constructed a cotton growth dynamic model (COTGROW), which integrates climate, soil environmental conditions and cultivation management measures by applying the theory and method of crop model. It takes daily climate conditions as the driving variable, soil conditions as the basis, cultivation measures as the influencing factors, carbon balance as the core, and comprehensively considers soil, plant moisture and minerals. ?
It is worth pointing out that most of the above dynamic models do not consider the feedback mechanism and interaction of the process. Ji Jinjun (1996) combined the physical processes of land atmosphere, vegetation and soil with the physiological and ecological processes of plants, and established a two-way interaction process model between vegetation and atmosphere. Among them, the air-vegetation interaction model is coupled by the plant growth mechanism model and the air-vegetation soil physical transport model (that is, the land surface process model). The land surface process model includes the energy and water transport processes among the atmosphere, vegetation and soil, and these processes will change their intensity and distribution with the annual change of plant growth. Plant growth model includes photosynthesis, respiration, distribution of dry matter in various tissues and decomposition of litter. These processes vary with the temperature and humidity of the atmosphere and vegetation soil, photosynthetic effective radiation and CO2 concentration in the atmosphere. The model has been used to simulate the annual changes of biomass, CO2, energy and water flux in temperate coniferous and broad-leaved mixed forests, and has strong simulation ability. If nested with the regional climate model, it can also predict the regional impact of climate change. This is a promising dynamic coupling model.
- Previous article:What do the numbers below pm2.5 in the weather forecast mean?
- Next article:What's the phone number of 12 1?
- Related articles
- Will the vacuum pump of electric vehicle break down in cold weather?
- What should I pay attention to when traveling in Tunisia?
- Why is there frequent dusty weather in the north this year?
- Gusu district, Suzhou has carried out a special inspection on safety production in hot weather. What are the safety hazards in hot weather?
- Romance in the circle of friends (two articles)
- Basic introduction of Guizhou water monster
- Crazy mother-in-law in Hebei predicts that there will be demolition in 202 1 and 202 1 in Jiang 'an District.
- Recommended places to visit Dujiangyan in summer
- Food service legal knowledge
- What are the maintenance methods of planting? What are the maintenance methods of potted plants?