Liu Dianwei

A GIS-based Tupu analysis of dynamics of saline-alkali land in western Jilin Province

Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da’an City of the western Jilin Province in 1980–2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da’an during 1995–2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography, predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da’an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da’an fluctuated greatly. The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development.

Spectral absorption properties of particulate matters in the Shitoukoumen Reservoir of Changchun City

The Shitoukoumen Reservoir, an urban water resource of Changchun City, was chose as a represent case of waters in Northeast of China, and then its spectral absorption properties of particulates were analyzed using the field data on June 13th and September 23rd 2008, respectively. Results showed that the content of total suspended matters (TSM) was higher but content of chlorophyll-a (Chl.a) was lower in June than that in September. The spectral curves of TSM were similar to that of tripton. Tripton contributed much more than phytoplankton in the absorption by TSM. In September, the contribution coming from phytoplankton slightly increased, which resulted in an obvious absorption peak around 440nm in the spectral absorption curves of TSM. Absorption by tripton at 440nm had a good relationship with TSM but not with Chl.a. The absorption of phytoplankton in Shitoukoumen Reservoir was generally low. Chl.a held the majority of the pigment composition and had good exponential relationships with its absorption at 440nm and 675nm, respectively. The average values of phytoplankton specific absorption coefficient at 440nm and 675nm in June were 0.0483m2/mg and 0.0263m2/mg respectively, while the data in September were 0.0337m2/mg and 0.0187m2/mg respectively.