Spatial Downscaling of Tropical Rainfall Measuring Mission (TRMM) Annual and Monthly Precipitation Data over the Middle and Lower Reaches of the Yangtze River Basin, China
WATER
Authors: Chen, Shaodan; Zhang, Liping; She, Dunxian; Chen, Jie
Abstract
Precipitation plays an important role in the global water cycle, in addition to material and energy exchange processes. Therefore, obtaining precipitation data with a high spatial resolution is of great significance. We used a geographically weighted regression (GWR)-based downscaling model to downscale Tropical Rainfall Measuring Mission (TRMM) 3B43 precipitation data over the middle and lower reaches of the Yangtze River Basin (MLRYRB) from a resolution of 0.25 degrees to 1 km on an annual scale, and the downscaled results were calibrated using the geographical differential analysis (GDA) method. At present, either the normalized difference vegetation index (NDVI) or a digital elevation model (DEM) is selected as the environmental variable in the downscaling models. However, studies have shown that the relationship between the NDVI and precipitation gradually weakens when precipitation exceeds a certain threshold. In contrast, the enhanced vegetation index (EVI) overcomes the saturation shortcomings of the NDVI. Therefore, this study investigated the performances of EVI-derived and NDVI-derived downscaling models in downscaling TRMM precipitation data. The results showed that the NDVI performed better than the EVI in the annual downscaling model, possibly because this study used the annual average NDVI, which may have neutralized detrimental saturation effects. Moreover, the accuracy of the downscaling model could be effectively improved after correcting for residuals and calibrating the model with the GDA method. Subsequently, the downscaled rainfall was closer to the actual weather station rainfall observations. Furthermore, the downscaled results were decomposed into fractions to obtain monthly precipitation data, showing that the proposed method by utilizing the GDA method could improve not only the spatial resolution of remote sensing precipitation data, but also the accuracy of data.
Multi-aspects of emotional electrocardiogram classification in combination with musical stimuli and composite features
INTERNATIONAL JOURNAL OF APPLIED PATTERN RECOGNITION
Authors: Goshvarpour, Atefeh; Abbasi, Ataollah; Goshvarpour, Ateke
Abstract
A new evaluative methodology for classifying emotional electrocardiogram (ECG) was designed based on composite features of wavelet transform and recurrence analysis. To this end, the recurrence dynamics of decomposed ECG were analysed. The ECGs of 20 college students (7 females; and 13 males) were recorded during four emotional states induced by music. Emotion recognition was performed using Fisher, quadratic, and linear perceptron. Moreover, the relevance of the proposed recurrent features has been appraised by means of linear discriminant analysis (LDA), principal component analysis (PCA), Kernel PCA, generalised discriminant analysis (GDA), and Laplacian eigenmaps. The results suggest that LDA outperforms the other techniques. The effect of self-assessment ranks and gender on classification accuracies was also examined. Considering self-assessment scores, higher accuracy rates were achieved. Totally, the maximum rate of 96.15% was attained for women. It seems that the proposed algorithm can open a new horizon in emotion recognition.