城市化进程中武昌沙湖流域面源污染负荷时空分布模拟

Simulation of spatial temporal distribution of NPS loadings in Shahu Lake watershed during process of urbanization

利用遥感影像图进行武昌沙湖流域的土地利用分类,利用元胞自动机(CA)模型预测2011-2015年的土地利用变化,将CA预测结果与面源模型相结合,预测2015年沙湖流域面源污染物总氮(TN)、总磷(TP)、生化需氧量(BOD)负荷的时空分布.研究结果表明2003-2010年间,建设用地面积不断扩展,其他地类向建设用地转变速度依次为:农田56.8%、绿地35.1%、水域23.9%、未利用地8.9%.2011-2015年间各用地类型均有继续向建设用地转变的趋势.从污染物负荷总量的变化情况上看,2015年3种污染物的负荷总量较2003年均有较大幅度增长,其中:TN增长30.11%,TP增长17.32%,BOD增长43.38%.从污染物负荷总量的空间分布差异上看:TN由2003年的建设用地>绿地>农田>未利用地,转变为2015年的建设用地>未利用地>农田>绿地;2015年TP和BOD的污染负荷总量空间分布规律与2003年保持一致,为:建设用地>未利用地>农田>绿地.

The paper uses TM remote sensing data to classify the land use type of Shahu Lake watershed and uses cellular automata model to forecast the transformation of land use type from 2011 to 2015;and then conbining combine the forecast results with non-point source pollution model to simulate temporal variation and spatial distribution of NPS Loadings of Shahu Lake in 2015.The results are as follows： During 2003-2010,urban area was expanding continuously,other types of land use were decreasing at a speed of： farmland 56.8%,greenland 35.1%,water area 23.9%,barren land 8.9.During 2011-2015,the other types of land use have the trend to transform into urban area.From the volume dose variation of NPS pollutants we can see that： compared with 2003,the volume dose of these three pollutants had increased substantially by 2015;the increasing speed are： TN 30.11%,TP 17.32%,BOD 43.38%.From the spatial distribution of NPS pollutants loadings we can see that： in 2003,the spatial distribution of TN was urban area greenland farmland barren land,while in 2015,the regularity of distribution becomes urban area barren land farmland greenland;in 2015,the spatial distribution of TP and BOD are the same with 2003;the regularity of distribution are urban area barren land farmland greenland.