HR: 1330h
AN: GC12A-0148    [PDF]
TI: Climate Response in the Global Warming: Increasing Rate of the Surface Temperature
AU: * Yokohata, T
EM: yokohata.tokuta@nies.go.jp
AF: National Institute for Environmental Studies, 16-2, Onogawa,, Tsukuba, Ibaraki, 305-8506 Japan
AU: Ogura, T
EM: ogura@nies.go.jp
AF: National Institute for Environmental Studies, 16-2, Onogawa,, Tsukuba, Ibaraki, 305-8506 Japan
AU: Nozawa, T
EM: nozawa@nies.go.jp
AF: National Institute for Environmental Studies, 16-2, Onogawa,, Tsukuba, Ibaraki, 305-8506 Japan
AB: It is uncertain to what extent the surface temperature increases owing to the rise in the atmospheric level of the anthropogenic greenhouse gases in the atmosphere. This is because the earth climate system is very complicated and thus the many feedback processes affect the climate response. One of the important methods to answer this question would be the analysis of the increasing rate of the surface temperature, even though it has not been carried out enough in the previous works. In this study, therefore, we investigate the mechanisms which determine the increasing rate of the surface temperature under given radiative forcings. For this purpose, we perform the numerical simulations with 1 %/yr increasing CO2 by using CCSR/NIES GCM. We investigate the radiative energy budget at the top of the atmosphere (TOA), and distribution of the water vapor and clouds in the atmosphere. Our results are summarized as follows; 1) Increasing rate of the global mean surface temperature (unit: K/s, we call this dTs/dt hereafter) are different depending on the atmospheric level of CO2. dTs/dt increases when the CO2 level is lower than the twice as the present one, while dTs/dt decreases when the CO2 level is between the twice and three times as the present one. 2) Our analysis of the TOA radiation budget indicate that dTs/dt would be determined by the increasing rate of net atmospheric absorption of the infrared radiation, rather than that of net incoming solar radiation. 3) The trend of the increasing rate of the water vapor column density is consistent with that of dTs/dt. This consistency suggests that the role of the water vapor feedback in the climate system would be important.
DE: 1610 Atmosphere (0315, 0325)
DE: 3309 Climatology (1620)
DE: 3319 General circulation
DE: 3359 Radiative processes
SC: Global Climate Change [GC]
MN: 2003 Fall Meeting