4-2a Warming and atmospheric composition change interaction model
4-2b A warming-cloud, aerosol, and radiation feedback precision evaluationThe ozone in the atmosphere is bearing the important role in the dynamic meaning and the environmental study-meaning. Moreover, itself is not only important for global warming or global environment problems, but chemical substances, such as steam, OH radicalness and NOx, and carbon monoxide, can have great influence on other warming gas, such as sulfuric-acid aerosol and methane, besides ozone. For this reason, it is thought that it is important to conduct a warming prediction experiment using the model in consideration of an interaction with atmospheric chemistry after that elaboration, quantification, and warming process of a forecast understand.
In the University of Tokyo climate center, National Institute for Environmental Studies, and the Frontier Research System for Global Change, the general circulation model explicitly combined with photochemical-reaction process was developed, and prediction experiment (Nagashima et al., 2002), Pinatubo volcanic eruption impact evaluation (Takikawa, 2000), impact evaluation (Sudo et al., 2001) to the troposhere ozone of ENSO, etc. have so far been studied in the future [ stratosphere ozone hole ]. In this symbiosis project, it extends to the general circulation model combined with the photochemical processes of the stratosphere and the troposhere based on the model (CHASER) which incorporated the troposhere photochemistry model in detail, and the Earth Simulator is used and high resolution time slice simulation based on the emission scenario of shoes is performed. The point of fixation in this time is influence which it mainly has on the photochemistry-life of methane with change of OH radical by a climate change in the troposhere. In the stratosphere, it is the interaction of the ozone destruction effect similarly activated by the heterogeneous reaction on change of the stratosphere water vapour content by a climate change, a polar stratosphere cloud, and its surface. Since it unites and cumulus convection activity is changed by a climate change, I think that he wants to evaluate also about change of the amount of thunder NOx generation which occurs in that case.
Next, troposhere aerosol model developed by the University of Tokyo climate center and the Kyushu University applied mechanics research institute Stratosphere aerosol is included in SPRINTERS and impact evaluation to the aerosol of a chemical process is performed using the aerosol-chemistry-climate model combined with CHASER. Sulfuric-acid aerosol has received big influence in the chemical process among troposhere aerosol. This is because precursor gases, such as sulfur dioxide emitted from surface of the earth, serve as sulfuric-acid aerosol by a reaction with the ozone in a vapor phase and a liquid phase, hydrogen peroxide, and OH radical. Moreover, the artificial origin emission of sulfur dioxide is considered to change a burst size sharply by a future Asian region, especially Chinese economic development, and is very important for considering the impact evaluation to the climate in detail in future warming research.
After evaluating the interaction between each process which used these partial integrated models, construction of a final integrated model is begun. Besides an interaction which was described previously, it is possible to evaluate the influence on the ecosystem by discharge of the nonmethane hydrocarbon from a terrestrial ecosystem model and the acid rain conversely forecast from an atmospheric chemistry model, and the amount of ozone etc. Moreover, although it is said on the ocean that sulfuric-acid aerosol is important as a cloud condensation nucleus, I also think that he wants to examine predicting the burst size from the ocean of DMS as the source of generation to the atmosphere within a marine ecosystem model in the future.
 Fig. 5: Warming and atmospheric composition change interaction model key map. As for that by which integration is made at present as for the black arrow, and a red arrow, what is planning integration from now on is shown, respectively. |
4-2b A warming-cloud, aerosol, and radiation feedback precision evaluation
4-2a Warming and an atmospheric composition change interaction modelAs it is also in the report of IPCC2001, the estimate of the indirect radiation legal force of troposhere aerosol is the problem that uncertainty is still large, and the main factor is because aerosol and the relation of clouds are indefinite. Although it works as a condensation nucleus (Cloud Condensation Nuclei:CCN) of a cloud particle in aerosol, the particle size distribution of a cloud particle is decided by particle size distribution, chemical composition, and upward flow speed in clouds, the efficiency of precipitation of the optical characteristics, such as reflectance of clouds and optical thickness, the rain ease of coming down, etc. changes, as a result it comes to radiation balance or a water cycle in climate change prediction. In order to clarify such causal relationship, the numerical simulation by a detailed cloud model is indispensable. In this symbiosis project, parameterization for a general circulation model (GCM) to estimate the influence aerosol affects the optical characteristic of clouds is developed.
If the example of the present GCM is given, first, in CCSR/NIES, the effective radius of the cloud particle used for radiation calculation will be calculated from cloud particle number density, and the cloud particle number density will be computed from aerosol number density. In proportion to aerosol number density, when the formula used here has little aerosol, if it increases, it is a formula showing approaching a steady value, and the rough tendency suits, but it can also call the thing used as CCN a problem that they are a number of aerosol of all included functions and that upward flow is not taken into consideration. Moreover, Max Plank Institute In ECHAM GCM, cloud particle number density is the function of aerosol number density and the upward flow speed in a cloud. The upward flow speed in a cloud is found from the average upward flow speed in a grid. How of the clouds in the inside of a lattice to find the upward flow speed in clouds comparatively is a subject.
On the other hand, on the frontier, a detailed cloud model much finer than GCM is developed, and parameterization which predicts the optical property and cloud particle number density of clouds by numerical simulation is developed. The result of the numerical simulation in various conditions was unified, and the formula which predicts the maximum of the degree of supersaturation in clouds as a function of the upward flow speed in the degree spectrum of supersaturation and cloud base of CCN was developed. Moreover, the formula which predicts cloud particle number density as the number of CCN(s) which can be activated with the degree of the maximum supersaturation in clouds, and a function of the upward flow speed in a cloud base was developed. Furthermore, the formula which predicts the optical thickness of clouds from the cloud particle number density and the perpendicular addition liquid water content of clouds which were predicted was also developed. Similarly, it is also possible to express the effective radius of the cloud particle of each class in a cloud with the advanced function from cloud particle number density and a cloud base. Moreover, although accuracy fell, the method of predicting cloud particle number density was also directly developed from the CCN spectrum. It is possible to predict cloud particle number density using this from the optical thickness and perpendicular addition liquid water content of the clouds obtained independently of satellite observation etc., and to count CCN number density backward in accordance with the upward flow speed in a cloud base. This method is very effective in observing not aerosol but the information on CCN in the long run in all balls.
In order to develop parameterization which can evaluate the influence of the climate on aerosol (CCN) for including in GCM as a line of investigation, parameterization already used by GCM at present is examined first, and better parameterization is developed together with the result of the numerical simulation by the detailed cloud model developed here. In this case, although calculation of the rate that expresses the clouds of a sub grid scale how from the forecast variable of GCM, or the clouds in a grid occupy, the upward flow speed in a cloud, and the perpendicular addition liquid water content of clouds etc. becomes a problem, about this point, it cooperates with other groups and solves.
It is CCSR/NIES GCM in the current fiscal year. It started for examination of ECHAM GCM and the inquiry of the problem and the calculation result using them were examined. As a problem, the formula of the parameter of the calculation method of the rate of the clouds in a grid, the calculation method of the upward flow speed in clouds, and the conversion time constant from liquid water content to the amount of rain water etc. has gone up. And as a plan, it has agreed on the following things.
- The influence of aerosol is treated by the set of CCN and upward flow speed.
- The information on aerosol is rebroiled to the information on CCN (from the place where (NH4) 2SO4, NaCl, etc. are made in the beginning).
- According to present ECHAM-GCM, derivation of upward flow speed is improved at the beginning, if required.
- The diagnostic type of cloud particle number density is made first. It aims at making cloud particle number density into a forecast variable by making this into a generating clause. Depending on the length of a time step, a diagnostic type may sometimes be enough.
- If there is necessity, the category division of the cloud ice concentration will be carried out (since gravity fall speed differs greatly). It may be needlessness if it depends on layer thickness.