西南生态环境过渡区日照空间模拟及时空演变趋势分析--以重庆市为例

Simulation and Spatio-temporal Analysis of Sunshine in Southwest Ecological Transition Zone:a Case Study in Chongqing

利用Solar Analyst模型,结合DEM、日照百分率,选择重庆市作为西南生态环境过渡区的代表,建立了一种起伏地形下日照时数的空间模拟方法,模拟结果能够精确反映出日照的年内变化及微地形的影响特征。进一步对日照时数时空序列拟合结果进行了100m×100m像元尺度的分析。结果表明:1)全市年均日照时数以东北部最高;其次为中西部;东南部、南部偏低。春、夏季以东北部以及中西部日照时数最高,东南部最低。秋、冬季以东北部为日照高值区,东南部和中西部为低值区。日照受坡度、坡向以及地形遮蔽影响明显。2)整体趋势上,年以及春季、夏季、冬季日照时数均呈现一定的线性减少趋势,其中年均日照时数80年代前后趋势差异明显;春季经历了减少、增加、平稳3个阶段;夏季减少趋势最明显;冬季减少趋势最稳定;秋季无明显变化趋势。3)空间变化上,年以及四季日照时数变化趋势存在区域差异,各季节西部减少最为明显;秋季中部增加趋势最为显著;春季盆周山地区增加相对明显;除春季外,其他季节东南部日照均呈减少趋势。

In this paper, Solar Analyst model was used to simulate sunshine in rugged terrains of Chongqing from 1960 to 2010. TheDEM and sunshine percentage of meteorological stations was also used in this model. It proved that the method has high stability.Further, temporal and spatial analysis about change trend of sunshine duration was made. Research shows that： 1） Average annualdaily sunshine was highest in the northeastern area with the middle and West of Chongqing on its heels. Sunshine was highest in thenortheast and south of Chongqing in the spring and summer. In the fall and winter, there were higher sunshine in the northeast, thesunshine was lower in the southeast and Midwest of Chongqing. The more complex terrain combined with the effects of slope, as-pect and shade, the difference of sunshine is larger. 2） Average annual daily sunshine of Chongqing showed a certain linear decrea-sing trend, and experienced a significant drop in early of the 1980s in spring sunshine showed no obvious decreasing trend, but highinter-decadal difference. Summer sunshine showed a fluctuated decreasing trend. Autumn sunshine had no obvious change trend.Winter sunshine had the most stable decreasing trend than other seasons. 3） The trend of annual and seasonal daily sunshine ofChongqing showed regional differences. And it decreased the most obviously in the western area. Autumn sunshine had a relativelyobvious increasing, and there was a same trend in the surrounding mountain areas in spring. In addition to spring, sunshine ofsoutheast and west had similar decreasing.