论文部分内容阅读
在美国加州,75％的农业用水来自内华达山上积雪场的融化。用专题制图仪所获得的该流域范围内的光谱反射率,可较好地进行春季的融雪径流预报。鉴于专题制图仪具有较大的动态响应,故在积雪场研究中,它比多波段扫描仪优越。在TM1—4波段中,也存在着饱和现象,不过仅是TM1(0.45μm—0.52μm)较为严重。雪在TM2(0.53μm—0.61μm)上的反射率可以做为整个可见光波段上的反射率的代表,此波段的反射率对雪的晶体颗粒大小几乎没有什么显著的反应,但对雪的污染极为敏感。TM4(0.78μm—0.9μm)可用于估算雪的有效光学粒径。TM5(1.57μm—1.78μm)可以把云从雪中分辨出来。
In California, USA, 75% of agricultural water comes from melting snow fields in Sierra Nevada. Spectral reflectance within the catchment area obtained by thematic plotter is a good predictor of snowmelt runoff in spring. Because the thematic mapping instrument has a large dynamic response, it is superior to multi-band scanner in snow field research. In the TM1-4 band, there is also saturation phenomenon, but only TM1 (0.45μm-0.52μm) is more serious. The reflectance of snow on TM2 (0.53μm-0.61μm) can be used as a proxy for the reflectance over the entire visible wavelength range. The reflectance of this band has little or no significant response to snow crystal particle size, but snow contamination Extremely sensitive. TM4 (0.78μm-0.9μm) can be used to estimate the effective optical particle size of snow. TM5 (1.57μm-1.78μm) can distinguish the cloud from the snow.