What is UJCC ?
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Thursday, 04 January 2007

What is the UK-Japan Climate Collaboration ?


Earth Simulator nodes

The aim of the UJCC project is to exploit the power of the Earth Simulator to produce world-leading climate simulations. The enhanced resolution models will allow unprecedented fidelity of simulation, and allow many emergent phenomena to be resolved. The science of the project will then be to understand how the increased resolution changes the large scale mean climate, consider whether the emergent processes are therefore essential to produce reliable climate models, and consider if these processes can be parameterized in lower resolution models, or if their importance is enough to drive model resolution to increase.

Models developed within UJCC, capable of resolving weather and climate processes, should allow us to improve the current generation of climate models, by providing guidance as to the quality of existing parametrisations. Computer simulation has in fact proven to be a practical and useful scientific methodology for making predictions concerning global environmental change.  These simulations are providing unprecedented opportunities to study weather systems and their relationship with regional and global climate variability.  A fundamental component of the collaboration is working alongside Japanese scientists at the Earth Simulator Centre and at the University of Tokyo, who have already developed and deployed models at high and ultra-high resolution to solve climate problems. Intercomparison of models and formulations at comparable resolutions allows us to answer questions about the suitability of current models for producing climate information at the regional scale.

The UK-Japan Climate Collaboration (UJCC) officially started in 2005. UK scientists, residing in Japan for the duration of this three-year project, have successfully ported the Hadley Centre's current climate model, HadGEM, to the Earth Simulator supercomputer, one of the most powerful on Earth. After developing a range of high-resolution model versions, UJCC scientists have performed climate simulations with unprecedented detail, enabling the study of important processes, such as ENSO, and of climate extremes, such as cyclones, typhoons, hurricanes. The UK portion of the project joins teams from the Hadley Centre (UKMO, Exeter) and the NCAS-Climate (National Centre for Atmospheric Science - Climate) at the University of Reading.


The Earth Simulator supercomputer


The Earth Simulator and its ability to run very high-resolution models of the entire global climate system has had a huge impact on climate research.  It has the potential to be utilized to help understand the location, frequency and severity of a range of climate phenomena. The Earth Simulator (ES) is one of the world's most powerful supercomputers.  Located in Yokohama, Japan, the ES was built by the Japanese government in 2002 under the Japanese Agency for Maritime-Earth Science and Technology (JAMSTEC). The ES is a highly parallel vector supercomputer system of the distributed-memory type, consisting of 640 connected processor nodes (PNs), each of which consists of 8 vector-type arithmetic processors (APs). The ES as a whole consists 5120 APs with 10TB of main memory and a theoretical peak performance of 40 Tflops. The computing capacity of the ES is being used to perform improved simulations of the past, present and future climate with complex climate models.  Improved current climate simulations allow us to have increased confidence in the future evolution of the climate system predicted by model simulations.  In order to fully utilise the capacity and capability of the ES it is not only used for climate (atmosphere-ocean) simulation, but also for other earth systems research, including geophysical simulations of the structure and dynamics of the whole Earth's interior, and for industrial applications, from the simulation of whole building environments for urban planning, to the simulation of organic material to assess its optical properties.


UJCC scientific highlights in year 1


Some very important phenomena have already emerged out of our line of research on increasing resolution:


Tropical instability waves

These are responsible for the eddy transport of heat in the equatorial ocean and have been shown to significantly contribute to the improvement of the modelled oceanic mean state (which normally displays a sizable cold bias in the coarser resolution models). The correct simulation of the oceanic mean state and of its inter-annual variability is a crucial pre-requisite to enabling the coupled models to properly simulate El Niño. El Niño is the oceanic component of ENSO (El Niño - Southern Oscillation), the major mode of global climate variability, and is an indispensable ingredient of any state-of-the-art climate simulation.


Regional distribution of precipitation

The smooth orography in the coarser resolution models causes an incorrect distribution of precipitation over the continents, due to poor definition of regions of surface convergence. The improvements in the regional distribution of precipitation are very important for the correct recharging of soil moisture, which is an indispensable resource for the maintenance of photosynthesis by land ecosystems, a major sink of atmospheric CO2.


Tropical cyclones, including typhoons and hurricanes

Unlike the standard climate models, NUGAM has sufficient resolution to spawn and sustain the organization of convective activity, which is necessary for the formation of tropical cyclones, some of which develop into typhoons and hurricanes. These extremely intense storms have a large impact on the global climate, because of their ability to transport heat and water vapor to the extra-tropics, but are also important in the study of extremes, which are associated with severe damage to life and property. An advanced visualization of some of the features simulated by NUGAM has been prepared in cooperation with NASA's Earth Observatory group. The animation is already being used worldwide for teaching and for public outreach.

Last Updated ( Tuesday, 17 July 2007 )