Program Activity
Climate Variations Research Program
From the home page of Disaster Prevention Research Institute, Kyoto
University (http://www.dpac.dpri.kyoto-u.ac.jp/mukou/meeting-03.html)
  On October 30-31st, 2003, a workshop titled "Tropospheric Low-frequency Variability and Abnormal Weather" (Principal implementor: Associate Professor Hitoshi Mukougawa), organized by Disaster Prevention Research Institute, was held at the Wood Composite Hall on the Uji Campus of Kyoto University. It was pointed out that the recent abnormal weather conditions in the world are somewhat different from those previous, both in frequency and intensity. Furthermore, it is increasingly recognized that the circulations in the troposphere are changing drastically by global warming. This workshop was aimed at gaining an understanding of the actual conditions of such abnormal weather and elucidating the mechanism of long-term variations in the troposphere, which are one of the causes of abnormal weather. Numerous research papers were presented by our program and others groups of Frontier Research System for Global Change. Group Leader Hisashi Nakamura, Researchers Meiji Honda, Shozo Yamane and Koutarou Takaya from this group participated in the workshop and presented research papers on the formation process of high pressure over the Sea of Okhotsk, the Aleutian Low, and intraseasonal variations in the Siberian High. Various issues on climate change were actively discussed among the researchers from all over the country. In the workshop, the abnormal weather recorded in the summer of 2003 was also discussed.
Hydrological Cycle Research Program
  The Clouds and Precipitation Process Group conducts joint Artificial Cloud Experiments with other research institutions every year, utilizing the Kamaishi mine shaft (approximately 450 meters in depth), to demonstrate indirect effects of aerosol. This year, we conducted the experiments at the end of November. Changing ascending velocity and the number density of cloud condensation nuclei, we were able to validate the detailed cloud physics models and parameterizations developed by our group. Dr. Chuang, University of California, Santa Cruz, came to join this experiment. He is interested in the effect of turbulence on the cloud droplet size distributions. After this year's experiments, we invited him to give a lecture, entitled "Studies of aerosol-cloud-climate interactions" at the Formal Seminar held at the Frontier Research System for Global Change.
Global Warming Research Program
  The Carbon Cycle Research Group conducts chlorofluorocarbons (CFCs) simulation, using an eddyresolving (0.1 degrees horizontal) ocean general circulation model (OGCM), jointly developed by the Climate Variations Research Program and the Earth Simulator Center. CFCs are absorbed at the sea surface and are carried within the oceanic circulation and mixing processes. The Figure below illustrates the results of simulated CFC-11 concentration in the deep North Atlantic Ocean. High concentration water of CFC-11 (shown in warm colors) is revealed to have recently absorbed CFCs from the atmosphere and then been ventilated into the northern North Atlantic, where is formed deep water which is important to global climate variations. Injecting CFCs into this sea area can visually capture the formation and spreading of deep water.
Atmospheric Composition Research Program
   A major goal of the Global Chemical Transport Modelling Group is to investigate and quantify the links between air quality and climate through the impacts of tropospheric ozone. Ozone is the third most important trace gas affecting climate, after CO2 and methane, and has been increasing much more quickly - by a factor of 3-4 over the past century. This change has been accompanied by increasing levels of 'smog' ozone near the Earth's surface, which affect human health and agricultural crop yields, and has been principally attributed to human activities. To address this goal, Dr. Oliver Wild participated in the NASA TRACE-P atmospheric measurement campaign over the Western Pacific in Spring 2001, and has recently provided detailed analyses of the production of ozone in the highly polluted air transported out of East Asia which was intercepted over the Western Pacific by measurement aircraft. While sunny, anticyclonic conditions were found to contribute substantially to the build-up of pollutant ozone over China, the impacts on climate were found to be larger under cloudy conditions when regional build-up was small. This unexpected result highlights the complex relationships, which exist between regional pollution and global climate, and demonstrates the additional insight that can be gained by combining high-resolution chemistry model studies with detailed measurements of tropospheric trace gases and aerosols.
Ecosystem Change Research Program
Below is a summary of the projects that the Marine Biological Process Model Group is now working on.
   Our group received Global Environment Research funding in 2003, and we began studies aimed at elucidating the mechanism of ocean ecosystem changes in the western North Pacific in cooperation with the Tohoku National Fisheries Research Institute etc. These studies focus on analyzing zooplankton samples (commonly called the "Odate Collection" after a collector, Doctor Odate) collected over the past 50 years. Other than the Odate Collection, only the Scripps Research Institute in the U.S. and the Sir Alister Hardy Foundation for Ocean Science in England possess plankton data stretching back over more than 50 years. By cooperating with these research institutes in comparing mechanisms in each sea area, we can expect to clarify the pattern of hemisphericscale climate-ocean ecosystem changes. Furthermore, although such monitoring has recently been dropped due to budget shortages, we expect that we can use the results of these studies to strengthen our case for continuous and steady monitoring.
Integrated Modeling Research Program
Introduction of the research of "Kyousei Project 7".
   We have been adding many modifications to the Coupled Atmosphere-Ocean-Sea Ice model for the Earth Simulator (CFES) to improve its performance. The simulation of the climate in the CFES composed by the Earth Simulator Center improved a lot by our intensive tunings of the parameterizations of the ocean and atmosphere parts, which were necessary for exploiting its full potential. Furthermore, we introduce newly developed land parameterization scheme MATSIRO±iMinimal Advanced Treatments of Surface Interaction and Runoff±jto the CFES instead of the current one layer model so called "bucket model". On the top of this coupled model, we are constructing the variational data assimilation system. We have started the design of the experiment to produce climatological reanalysis data. We are working hard for our final goal to provide the integrated reanalysis datasets of 1990s.
International Pacific Research Center (IPRC)
  Program Director Yamagata visited the IPRC in January and gave a seminar on the role of the Indian Ocean in climate forecasts.
   For progresses on research activities, as part of the IPRC-ESC-FRSGC collaboration, output from the Global Ocean Model for the Earth Simulator in the Indonesian region has been analyzed; results show that the model's outputs are very useful for understanding the complex flows in this very important region connecting the Indian and Pacific Oceans. An analysis with the IPRC-Regional Climate Model of satellite data showing that ocean fronts and eddies affect surface wind speeds has revealed that surface pressure gradient is the main force affecting wind speed. The nature of stirring and mixing of marine ecosystems has been found to have a significant effect on phytoplankton blooms, implying that small, unresolved, scales must be properly taken into account when embedding ecosystem models in climate models.
   The IPRC welcomed the following postdoctoral fellows: C. Tam is working with T. Li on studying tropical cyclones; H. Yoshinari is working with the Asia- Pacific Data Research Center, and A. Natarov is working with Kelvin Richards and J. McCreary on instabilities and mixing of the equatorial current system.
International Arctic Research Center (IARC)
Cyclone Activity Has Been Intensified in the Arctic
   Cyclones are key weather elements that comprise a major contributing part to climate trend and variability and bring intense high frequency changes in wind, temperature and precipitation. X. Zhang et al. investigated the Arctic cyclone activity in the context of climate change and variability by using a newly defined integrative index, the Cyclone Activity Index (CAI). Our investigation indicates that Arctic cyclone activity has increased during the second half of the 20th century, while midlatitude activity decreased from 1960 through the early 1990s. The number and intensity of cyclones entering the Arctic from the midlatitudes has increased, suggesting a shift of storm tracks into the Arctic. Positive tendencies of midlatitude cyclone activity before and after the 1960-1993 period of decreasing activity correlate most strongly with variations of cyclone activity in the North Atlantic and Eurasia. Our results also show evident interactions of cyclone activity between the Arctic Ocean and the Arctic marginal zone and as well as identify associations of significant interannual signals of the Arctic cyclone activity with the NAO and the regime alternation of Arctic sea-ice and ocean motions.
Frontier Newsletter/No.25
FRSGC Index
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