气候系统对二氧化碳强迫和太阳辐射强迫从1天到1000年时间尺度上响应的模拟研究

发布时间：2018-05-20 14:28

本文选题：气候模拟 + 太阳辐射强迫　；参考：《浙江大学》2017年硕士论文

【摘要】：自工业革命以来,人类活动(化石燃料燃烧、土地利用等)不断排放CO2等温室气体,造成全球气候变化。大气CO2增加产生的辐射强迫是造成全球变暖的主要原因。除了 CO2,太阳辐射、气溶胶等也是造成全球气候变化的重要外部强迫。本文以CO2强迫和太阳辐射强迫为例,利用HadCM3L气候系统模式,开展了一系列的模拟试验:(1)大气C02浓度突然增加4倍(4×C02试验),这个试验中既考虑C02通过吸收长波辐射对气候的影响(C02的辐射效应),又考虑C02通过影响植被气孔性质产生的气候效应(C02的气孔效应);(2)大气C02浓度突然增加4倍,但仅考虑CO2对长波辐射的吸收作用,而不考虑C02对植被的作用(4×C02 atm试验);(3)模式太阳常数突然增加4%,由1365.0 Wm-2增加到1419.6 Wm-2(4%Solar 试验)。CO2和太阳辐射等外源强迫发生后,气候系统的不同组成部分响应时间不同。大气和陆地地表具有较低的热容量,响应较快,而海洋热容量较大,温度变化较慢。近年来一些气候变化研究将气候系统对外源强迫的响应区分为"快响应"和"渐进反馈"。快响应是指全球平均温度,主要是海表温度发生明显变化之前气候系统的响应;渐进反馈是指随着时间推移,海表温度显著上升后引发的气候系统变化。本文从快响应和渐进反馈的角度出发,根据HadCM3L模拟结果,系统研究了气候系统在从外源强迫发生后的第1天到1000年后的连续演变过程,揭示CO2强迫和太阳辐射强迫对气候系统快响应和渐进反馈的影响异同。根据模拟结果,在强迫发生后的第1天,4×C02试验和4%Solar试验中大气层顶向下的净辐射通量(即外源强迫对气候系统的辐射强迫)分别为9.69 W m-2和6.30Wm-2,而在1000年后,气候系统达到准平衡状态时,全球表面平均温度升高了 5.71 K和5.70 K,这说明对于同样的平均地表温度变化,所需的太阳辐射强迫要大于所需的C02辐射强迫,即CO2辐射强迫的效率高于太阳辐射强迫的效率。通过对模拟结果的分析,发现辐射强迫效率的差异主要与地气系统快速调整过程中晴空长波辐射的变化有关。这主要是由于C02的辐射效应使得气候系统中更多的长波辐射被吸收,因此,第1年4%Solar试验中大气层顶更多的晴空长波逃逸到外太空。通过比较不同时间尺度上4×C02试验和4×CO2 atm试验中全球表面温度的变化,发现在强迫发生后的第1天,4×C02试验中陆地表面增温0.67 K,而4×C02 atm试验增温0.25K,在强迫发生后1个月后,4×CO2试验中陆地表面增温比4×CO2atm试验高将近1倍,说明强迫发生后的短时间尺度(大约1个月)上,CO2的气孔效应对地面增温有着重要作用。大气CO2浓度增加,使得植物叶片导度降低,植被蒸腾减少,潜热释放减少。同时,陆地上空低云云量减少,到达地面的太阳辐射增加,引起地表增温。在数年以上的时间尺度上,4×C02试验和4×C02atm试验温度变化差距随时间减小,模式达到准平衡状态时,4×CO2试验和4×C02 atm试验的地表平均温度为5.71 K和5.22 K,表明随着时间的推移,4×C02试验中C02的辐射效应对气候系统中全球表面温度的变化起主导作用。4×C02试验和4%Solar试验达到准平衡状态时全球平均地表平均温度变化基本相同,但二者造成降水的变化差异很大,相对于参照试验,4×CO2试验和4%Solar试验,降水分别增加了 5.41%和10.81%。利用线性回归的方法,将平衡态降水的变化表示为降水对外源强迫的快响应和降水对温度变化渐进反馈的线性叠加。模拟结果表明,对于CO2强迫和太阳辐射强迫,由于温度变化造成的降水变化基本相同。CO2强迫和太阳辐射强迫造成的降水差异主要体现在海表温度发生显著变化前的快响应阶段,在快响应阶段,就陆地而言,大气 CO2浓度增加,植被气孔导度降低,减少植被气孔向大气蒸腾的水汽,从而减少降水;就海洋而言,大气CO2增加,C02的辐射效应导致大气增温,而海洋的比热较大,海表温度变化落后于低层大气,低层大气垂直稳定度增加,抑制蒸发和降水。本研究有助于理解CO2和太阳辐射强迫对气候系统的影响机制,为预测未来气候变化提供理论基础。另一方面,研究气候系统对C02强迫和太阳辐射强迫的响应也有助于理解以减少太阳辐射为基础的地球工程产生的气候效应,为认知地球工程对气候系统的可能影响提供理论基础。
[Abstract]:Since the industrial revolution, human activities (fossil fuel combustion, land use and so on) continue to emit CO2 and other greenhouse gases, causing global climate change. The radiation forcing produced by the increase of atmospheric CO2 is the main cause of global warming. Besides CO2, solar radiation and aerosols are also important external forcing for global climate change. This article is based on CO2 As an example of forcing and solar radiation forcing, a series of simulated experiments are carried out using the HadCM3L climate system model: (1) the atmospheric C02 concentration is suddenly increased by 4 times (4 x C02 test). This experiment considers both the effect of C02 on the climate by absorbing long wave radiation (the radiation effect of C02) and the effect of C02 on the climate effect of the stomatal nature of the vegetation. It should be (the stomatal effect of C02); (2) the atmospheric C02 concentration suddenly increased by 4 times, but only considering the absorption of CO2 to the long wave radiation, without considering the effect of C02 on vegetation (4 x C02 ATM test); (3) the solar constant suddenly increased by 4%, from 1365 Wm-2 to 1419.6 Wm-2 (4%Solar test).CO2 and solar radiation and other exogenous coercion. The response time of different components is different. The atmosphere and land surface have relatively low thermal capacity, the response is faster, and the ocean thermal capacity is larger and the temperature changes slowly. In recent years, some climate change studies have classified the response of climate system to exogenous compulsion as "fast response" and "gradual feedback". The response of the climate system before the apparent temperature changes; gradual feedback is the climate system change caused by the rise of the sea surface temperature as time goes on. From the perspective of fast response and gradual feedback, this paper systematically studies the climate system from first days after the occurrence of exogenous compulsion to 1000, according to the results of HadCM3L simulation. The continuous evolution process reveals the differences and similarities between the CO2 forcing and the solar radiation forcing on the fast response and progressive feedback of the climate system. According to the simulation results, the net radiant flux of the top down of the atmosphere at the first days after the forced occurrence, the top down of the atmosphere in the 4 x C02 test and the 4%Solar test (i.e. the external forcing on the climate system) is 9.69 W m-2 and 6., respectively. 30Wm-2, when the climate system reaches the quasi equilibrium state after 1000, the global surface average temperature rises by 5.71 K and 5.70 K, which indicates that the required solar radiation forcing for the same average surface temperature changes is greater than the required C02 radiation forcing, that is, the efficiency of CO2 radiation forcing is higher than that of the solar radiation force. The results show that the difference in the radiative forcing efficiency is mainly related to the change of the clear sky long wave radiation during the rapid adjustment process of the earth gas system. This is mainly due to the radiation effect of C02 that makes more long wave radiation absorbed in the climate system. So, in the first year 4%Solar test, more clear sky waves from the top of the atmosphere escape to outer space. After comparing the changes of the global surface temperature in the 4 x C02 test and the 4 x CO2 ATM test on different time scales, it is found that the land surface temperature increases by 0.67 K in the 4 x C02 test after the forced occurrence, and the 4 x C02 ATM test increases the temperature 0.25K. After 1 months after the forced occurrence, the surface temperature increase of the land surface is nearly 1 times higher than the 4 x CO2atm test in the 4 x CO2 test. On the short time scale (about 1 months) after forced occurrence, the stomatal effect of CO2 plays an important role in increasing the temperature of the ground. The increase of CO2 concentration in the atmosphere reduces the plant leaf conductivity, the decrease of vegetation transpiration, and the decrease of latent heat release. At the same time, the low cloud cloud amount over land is reduced, the solar radiation to the ground increases, and the surface temperature increases. In several years, the temperature of the ground is increased. On the time scale, the temperature variation gap between the 4 x C02 test and the 4 x C02atm test decreases with time. When the model reaches the quasi equilibrium state, the average surface temperature of the 4 x CO2 test and the 4 x C02 ATM test is 5.71 K and 5.22 K, indicating that the radiation effect of C02 in the 4 * C02 test rises with the change of the global surface temperature in the climate system with the passage of time. The global average surface average temperature changes are basically the same when the leading role.4 x C02 test and 4%Solar test reach quasi equilibrium state, but the change of precipitation varies greatly between the two ones. Compared with the reference test, the 4 x CO2 test and the 4%Solar test increase the precipitation by 5.41% and 10.81%. linear regression method respectively, which will change the equilibrium precipitation. The result shows that the precipitation variation caused by CO2 forcing and solar radiation forced by the change of temperature is basically the same as that caused by the same.CO2 forcing and solar radiation forced by the change of temperature, which mainly reflects the change of the sea surface temperature. In the fast response phase, in the fast response stage, the atmospheric CO2 concentration increased, the stomatal conductance of the vegetation decreased, the air vapour of the vegetation was reduced to the atmospheric transpiration, and the precipitation was reduced. As for the ocean, the atmospheric CO2 increased, the radiation effect of C02 led to the atmosphere warming, and the ocean's specific heat was larger, the sea surface temperature was lagging behind the lower layer. This study helps to understand the effects of CO2 and solar radiation on climate systems and provide a theoretical basis for predicting climate change in the future. On the other hand, the study of the response of the climate system to C02 forcing and solar radiation is also helpful to understand the reduction of the solar radiation. The climate effect generated by earth based engineering provides a theoretical basis for the possible impact of cognitive geoengineering on the climate system.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P467;P435

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