松嫩高平原土地利用格局变化时间尺度特征研究

土地利用格局变化的时间尺度是其尺度依赖性和敏感性表达的重要基础。论文以松嫩高平原典型区域巴彦县为研究区,运用GIS、RS技术,结合Matlab编程,采用K-L变换将多波段的遥感影像提取为单波段图像作为原始信号数据,在研究区土地利用格局最优空间尺度下,应用快速傅里叶变换对小波分析模型进行改进,探寻研究区土地利用格局变化研究的适宜时间尺度,进而明确适宜时空尺度下土地利用格局变化的波动性特征,并采用土地利用转移矩阵对其时间尺度的划分结果进行检验。结果表明：1）研究区土地利用格局变化在10~20、30~40和40~50 a均有明显的波动性特征,表明10~20、30~40和40~50 a是研究区土地利用格局变化的3个重要时间尺度。2）1979—2015年研究区土地利用格局变化研究的最优时间分析尺度为36 a,土地利用格局在12.33 a左右具有明显的波动性变化特征,可将研究区时间域划分为3个发展阶段：发展初期1979—1991年、发展中期1991—2003年、发展近期2003—2015年。3）在空间上,研究区土地利用格局变化的全局化时间尺度和土地利用格局变化的局部化时间尺度具有较高水平的一致性。4）论文建立的基于小波分析的土地利用格局变化时间尺度识别方法可行并具有准确性,研究区旱地、林地和建设用地等主要土地利用类型在1979、1991、2003和2015年4个重要时间节点上的变化发生了明显的趋势性转换。

Study on Time Scales Characteristics of Land Use Pattern Change in Songnen High Plain

The scale dependency and sensitivity are important characteristics of land use pattern change. Taking Bayan County in Songnen High Plain as the empirical study area, the paper extracts single band image data as the original signal from multi-band image with K-L transformation. On the optimal spatial scale of the land use pattern in the study area, the wavelet analysis model was improved with fast Fourier transform to explore the appropriate time scale of land use pattern change in the study area. The model can automatically identify the land use pattern change and clarify the volatility characteristics of land use pattern change on appropriate time and space scales. Land use transfer matrix was used to test the results of time scale. The conclusions are as follows. Firstly, the land use pattern change showed volatility characteristics on time scales of 10-20 years, 30-40 years and 40-50 years. The volatility of land use pattern change on time scale of 40-50 years was the most intensive one, followed by the volatility on time scale of 30-40 years, and the volatility on time scale of 10-20 years was the least. Secondly, the optimal time scale for analysis of land use pattern change is 36 years in the study area during 1979-2015. Land use pattern has obviously volatility characteristics around 12.33 years. The study area can be divided into three development stages: the early stage is from 1979 to 1991, the medium stage is from 1991 to 2003, and the recent stage is from 2003 to 2015. Thirdly, the global time scale and the local time scale of land use pattern change were highly consistent in the study area. Finally, the main land use types, such as dry land, woodland and construction land, underwent obvious trend of conversion in the years of 1979, 1991, 2003 and 2015.