| 摘要: | 研究期間：10108~10207;Atmospheric carbon dioxide concentrations and global temperatures are two keys for observing present climate and for predicting future climate change. Human emit about 30 billion tone of carbon dioxide each year. About half of these emissions remain in the atmosphere, while the rest are absorbed by terrestrial vegetations and oceans. What are the temporal variations and spatial distributions of carbon dioxide absorbed by the vegetations and oceans? Can these natural absorbers continuously provide human such a great buffer for the carbon dioxide that human has been enjoying for the past 50 years? In a world with projecting increase in fossil fuel usage, changes in the capability of these natural processes in absorbing carbon dioxide from the atmosphere remains unknown. Ground-based stations such as Mauna Loa and other NOAA CMDL stations continuously provide excellent long-term measurements of carbon dioxide. These stations are good in showing long-term trend of carbon dioxide in the atmosphere. However, station-based data are limited by its spatial coverage. They cannot answer where and when the carbon dioxide been absorbed over the oceans and terrestrial vegetation. Until we are able to proactively go out to measure carbon dioxide in the air above oceans, in the surface ocean, and over the forests, our understanding of where and when the carbon dioxide been absorbed each year remains elusive. Hence, measuring carbon dioxide on a global scale has become a top priority for the past few years by top international institutes. These efforts include the Japanese GOSAT (Greenhouse gas observing satellite), successfully launched on 23 Jan 2009; the US OCO (Orbiting Carbon Observatory), launched on 24 Feb 2009 but was unable to reach the orbit; the US HIPPO project; the Japanese CONTRAIL project; the EU MOZAIC and IAGOS-ERI projects; the EU ICOS project; and the EU CARVASSO and CARBOOCEAN projects. On the other hand, observations of global temperatures contain uncertainties. Conventional observations (synoptic observations) are mainly provided by ground-based stations and radionsonde stations. Asynoptic observations are provided by ships, buoys, pilots and profilers, aircrafts, and satellite radiance retrieval. Since temperature observations are widely used as a key parameter to characterize current climate and climate trends, the use of more accurate temperature measurements can significantly improving our understanding of current climate and climate trends. The main purpose of this project is to produce accurate, long-term, and sustainable measurements of carbon dioxide over the oceans and terrestrial vegetations; and to produce better estimates of global temperature trends using temperature measurements from FORMOSAT-3/COSMIC GPS radio occultation measurements. In doing so, we can help track global distributions of carbon dioxides following their emissions on a finer temporal and spatial scales, and try to work out a genuine global temperature distribution in the context of rising carbon dioxide concentrations. A better knowledge of global carbon dioxide distribution can lead to better estimates of the sources and sinks of carbon dioxide from regional to global scales; a better knowledge of global temperature distribution can contribute to the assessment of current and future climate trends. These efforts are expected to play a significant role as the world moving toward a more stringent control of global carbon emissions and as the world entering a new decade predicted to be warmer than the 2000-2009. In addition, this project will expand the current global carbon dioxide observations now undertaken by international projects such as GOSAT, CONTRAIL, HIPPO, AQUA AIRS, ICOS, IAGOS-ERI, CARVASSO, and CARBOOCEAN; and the current global temperature observations undertaken by earth-observing satellites. |
