3. Cryospheric model developmentResults Page | Top Page |
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The organization in charge: Earth frontier research system
a. SummaryIt was adapted for Greenland and the South Pole in the ice sheet model developed so that reality might often be expressed, and the response characteristic of the ice sheet to warming was investigated. When the climate of the Greenland area carried out warming 3-4 times, that dissolution of the ice sheet equivalent to about 3m of sea levels takes place and climate carrying out warming of the South Pole area 7-8 times or more, and bringing about the sea level rise by dissolution of an ice sheet at last were shown. Moreover, the adjustment and the sensitivity experiment of an air sea sea ice joint model which do not have artificial flux regulation using an Earth Simulator were conducted. As a result of investigating the response characteristic over the reproducibility and warming of the climate of high latitude with high warming sensitivity, or sea ice [ all balls / especially ], a possibility that the grade of the reproducibility of the climate of Northern Hemisphere high latitude or warming of the Greenland ice sheet circumference would be greatly influenced by reproducibility, such as sea depths circulation, a position of a convection, and strength, was shown. In order to investigate in more detail whether the result of an air sea sea ice joint model affects ice sheet change however from now on, air - ice sheet combination (partial integrated model) is started. b. Research purposeAn ice sheet is ashore, there is sea ice in earth top north-south two poles at sea, and those generation change is directly linked with the climate change of an earth scale. For this reason, in connection with warming, an ice sheet and sea ice react sensitively, and we dissolve, or are anxious about affecting still wide range climate and sea surface change. So, into this group, the atmosphere / ocean / sea ice / ice sheet joint model which finally works on an Earth Simulator are built, and the prediction experiment of global warming or sea surface change is conducted. First, it strives for grasp of an indefinite element through various sensitivity experiments, improving a partial model. Furthermore, it aims at raising the accuracy of a prediction experiment, conducting the reappearance experiment of the present or the past using the combined model. Moreover, since the past climate and the restoration of ice sheet change / sea level by the data of a seabed sediment or geographical feature have come to be considerably performed with high precision about the last glacial epoch or subsequent ones 20,000 years ago, the model is verified through trying the numerical simulation reproducing this. c. A research program, a method, a scheduleThe mass of an ice sheet was decided by the dynamics process of ice sheets, such as snowfall, flow modification of the ice of an inside besides the interaction of dissolution and the atmosphere called a re-freeze, and a bottom slide. If influenced by warming, an ice sheet will receive the negative feed back (mechanism which presses down the mass loss as the whole ice sheet) by the increase in snowfall, or modification of ice, or it not only dissolves, but will receive the positive feedback to the temperature and dissolution by area or advanced fall conversely. Moreover, the increase in melten water, change of ice temperature, and a flow and change of a bottom slide bring positive or negative feed back to ice sheet change through the atmosphere or sea depths circulation. So, it is necessary to consist of a climate model which calculates precipitation, temperature, radiation, etc., a surface mass income-and-outgo model which calculates the amount of dissolution etc., and an ice sheet dynamics model which predicts a flow, bottom slide, and form of an ice sheet, and since they are closely related, it is necessary to combine with prediction of ice sheet change. Manufacture of a partial model was briefly performed by FY 2002, and the response characteristic has been investigated. From now on, improve each portion or the parallelization optimization of the ice sheet model program is carried out for Earth Simulators, or a coupling agent is developed and the characteristic of combination of a climate model and an ice sheet dynamics model is investigated.
Moreover, on the symbiosis first division title, Center for Climate System Research, University of Tokyo (CCSR), National Institute for Environmental Studies (NIES), and an earth frontier research system (FRSGC) are furthering development of an air sea joint general circulation model (OAGCM'MIROC') together. The integrated model development of a symbiosis second division title is due to further based on this OAGCM. About sea ice, combination is already completed and the sea ice dynamics portion has mainly been examined in detail till FY 2002. It is planning examining the elaboration of a sea ice thermodynamics portion after FY 2003. Observation research of other subjects (advancement of parameterization of many physics process (the atmosphere and the sea field)) of a symbiosis project stays in touch closely, and more realistic and essential process is taken in. d. The research program in FY 2002In the current fiscal year, it carries out focusing on development of the partial integrated model of an air - ice sheet. The partial integrated model using an easy air model is that (Omori, 2003) successful which was performed in a tentative way, and adds the change for combining an ice sheet model with the coupling agent of a general circulation model (MIROC) based on this experience. Improvement of each portion of an ice sheet model and a sea ice model is preponderantly performed about the thermodynamics portion which influences especially mass change directly. Moreover, the parallelization optimization of the ice sheet model program is carried out for Earth Simulators, or a coupling agent is developed and the characteristic of combination of a climate model and an ice sheet dynamics model is investigated. e. Reports in FY 2002(1) It investigated about the response characteristic of the ice sheet model to warming. The time scale of change of the ice sheet in warming will reach from 100 years in 1000. According to ice sheet model independent calculation, about 8 times warming is required on about 2 times warming and the South Pole ice sheet on the Greenland ice sheet to contribute to the increase in a sea level by 2m. Since joint processes other than an advanced effect (Albedo feedback and precipitation change) are not taken into consideration this time, direct coupling is needed.
f. ConsiderationThe climate and the snow ice distribution characteristics in high latitude, such as warming change, were decided by the interaction of air - sea - snow ice. Although the sea ice model was already incorporated into the air sea joint model, since the tool to consider was created, it is a future subject to investigate the response characteristic of the climate of a high latitude region by the further numerical simulation and the further sensitivity experiment. Since it turned out that the interaction of sea ice and ocean circulation (convection) has big influence on climate especially in the Greenland region and the South Pole region where an ice sheet exists, it will investigate in detail from now on. Moreover, since the influence to which melten water affects a convection by dissolution of the ice sheet at the time of warming is also considered, it will be necessary to repeat examination from now on through creation of the partial integrated model of the ice sheet - air - ocean. Next Page (4. climate physics core model improvement) |