Abstracts for the 6th International GAME Conf.

3-5 December 2004

Kyoto Japan

Climatic Impact of Vegetation Change in the Asian Tropical Region

Kazuo Mabuchi (1), Yasuo Sato (1), Hideji Kida (3)

Using a global climate model which includes a realistic land surface model, several numerical simulations were performed to investigate the impact of Asian tropical vegetation changes on the climate. The control simulation, under conditions of the actual vegetation, and three vegetation change impact experiments were performed. The results of the impact experiments were compared with those of the control simulation. The horizontal resolution of the model used in these simulations was 1.875 degree, being finer than that of the models used in previous vegetation change impact studies. As a result, it was determined that the effects of vegetation changes in the Asian tropical region had spatially different features. The morphological, physiological, and physical changes of the land surface vegetation in the Asian tropical region certainly induce statistically significant climate changes in these and the surrounding areas. That is, from the results of the bare soil and C4 grass experiments, the decrease in the roughness length, and from the results of the green-less experiment, the decrease of the latent heat flux, exert strong influences on the horizontal and convective circulations of the atmosphere. Consequently, the distribution of precipitation will undergo change. Other energy and water balances at the land surface are also influenced by the vegetation changes, and the induced changes are generally statistically significant. The vegetation changes were implemented only in the Asian tropical region. There were, however, possible influences of the vegetation change on the mid-latitude atmospheric circulation. It was considered that the vegetation changes from the forest type to grassland or bare soil induced modifications in the Hadley and Walker circulations. In particular, the divergence/convergence anomaly pattern that appeared at the upper atmospheric level in the C4 grass experiment was very similar to that of an ENSO event. The height anomalies at the 500-hPa level were also similar to those found in an ENSO event. The possibility exists that the deforestation of the Asian tropical region could induce similar teleconnections as those associated with ENSO events. The influences of vegetation changes in the Asian tropical region were more complicated than those in the Amazon. One reason for this was that the Asian tropical region is strongly influenced by the Asian monsoon circulation; another reason being that the land-sea distribution and the distribution of vegetation in the Asian tropical region are not as simple as a tropical rain forest like the Amazon.

Submittal Information

Name : Date :
    Kazuo Mabuchi
    31-Aug-04-12:26:56
Organization : Theme :
    Meteorological Research Institute, Japan
    Theme 4
Address : Presentation :
    1-1 Nagamine, Tsukuba, Ibaraki 305-0052
    Only poster
Country : Abstract ID :
    Japan
    T4KM31Aug04122656
Phone : Fax :
E-mail :
    kmabuchi@mri-jma.go.jp