重庆地区MODIS/NDVI时间序列数据重建研究

The Reconstruction of MODIS/NDVI Time Series Data in Chongqing

基于时间分辨率为逐月、空间分辨率为1 km的MODIS/NDVI数据,利用WS、S-G、A-G和D-L这4种重建方法对重庆市2010~2014年间历年逐月的NDVI时间序列数据进行重建,并采用视觉对比、分地类像元对比、相关系数(R)、均方根误差(RMSE)、赤池信息准则(AIC)和贝叶斯信息准则(BIC)对4种重建结果进行了评价。结果表明:S-G和WS重建后噪声少,S-G的曲线最为平滑,A-G与WS保真性较好。其中,A-G的R>0.8和RMSE<0.05的分布面积最大,分别占总面积的89.41%和66.40%;WS次之,占72.76%和59.37%。此外,在模型效果分析中A-G的AIC和BIC评价结果最佳,WS在其他3种方法BIC评价结果较差的渝西地区也有较好的评价结果。

Chongqing is located in mountainous area where the vegetation is rich. It is greatly affected by the fog all year round. As a result, the noise of remote sensing image is serious and the affected area is large which have a great influence on the accuracy of related application.NDVI is one of the most important vegetation in- dex which has an important role in the study of global climate Change, vegetation change etc. In this paper, the MODIS/NDVI data are used, the time resolution of the data is monthly and the spatial resolution is lkm. The NDVI data of Chongqing city from 2010 to 2014 are reconstructed by four smoothing techniques： WS, S-G, A-G and D-L. The results are evaluated by visual comparison, pixel contrast of different land use types,correla- tion coefficient（R）,the root mean square error （RMSE）, Akaike Information Criteria （AIC） and Bayesianlnforma- tion Criteria （BIC）. In the visual contrast analysis, the results indicate that the noise of S-G technique and WS technique is lower than the others. In the pixel contrast of different land use types, the curve of S-G technique is the smoothest.In the fidelity analysis, R and RMSE are used to evaluate of the original data and data recon- structed by four technique, the result of A-G technique and WS technique is better. It also indicates that the A-G technique have the widest distribution, the value of R larger than 0.8 accounts for 89.41% of the total area and the value of RMSE smaller than 0.05 accounts for 66.40% of the total area. The WS technique is better than the other two techniques, accounting for 72.76% and 59.37% of the total area respectively. In the model effect analysis, the AIC and BIC evaluation results of the A-G technique are the best. The evaluation results of WS techniqueis good in Western Chongqing where the BIC evaluation results of other threetechniques are rela- tively poor, the result of S-G method is the worst.