黑河实验区地表反射率与植被指数的季节变化

SEASONAL VARIATION OF SURFACE ALBEDO AND VEGETATION INDEX OVER HEIHE EXPERIMENTAL AREA

本文利用NOAA10/11AVHRR资料得到了黑河实验区1,4,8,10月地表反射率与植被指数的分布图,并讨论了不同下垫面地表反射率与植被指数的季节变化特征。在方法中,重点讨论了反射辐射各向异性的订正问题。结果表明:实验区各种下垫面的地表反射率均有明显的季节变化,其图象能很好地反映各季地表反射率的空间分布状况。夏季,由于沙漠,戈壁与农田的植被指数有明显差别,植被指数分布图对复杂下垫面的特征有很好的显示能力。冬季,由于农田的植被指数降至与沙漠接近,其分布图对下垫面的分辨能力较差。

Surface albedo and vegetation index over Heihe experimental area in January, April, August and October are derived from NOAA 10/11 AVHRR data. Seasonal variations in surface albedo and vegetation index are discussed over the different underlying surfaces. In the method to derive surface albedo, more detail focuses on the problem of the anisotropic correction for the reflected radiance. It's shown that surface albedo of every surface type over the experimental area has obvious seasonal variation. The spatial distribution of surface albedo in each season can be shown quite well in satellite image. In summer, due to the great difference of vegetation index between desert/Gobi and farmland area, vegetation index image has better capability of showing the characteristics of complicated underlying surfaces. In winter, because the vegetation index of farmland area is reduced to approach to that of desert area, its image's capability of identifying the underlying surface types become much weak.