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| 基于MODIS和AMSR-E遥感数据产品的土壤水分降尺度研究 | |
| 其他题名 | A downscaling method for AMSR-E soil moisture products using MODIS derived TVDI (Temperature Vegetation Dryness Index) |
| 曹永攀 | |
| 出版年 | 2012 |
| 学位类型 | 硕士 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 被动微波传感器是目前业务化获取地表土壤水分产品的主要遥感手段，但其空间分辨率（~25km）一般都较粗，难以提供适用于流域尺度水循环研究的中高分辨率土壤水分数据。\n本文提出一个土壤水分降尺度算法，采用0.01°分辨率MODIS逐日地表温度产品（MOD11A1）和逐日地表反射率产品(MOD09GA)构建温度—植被指数特征空间（Ts-NDVI Space），计算得到0.01°分辨率的TVDI（Temperature Vegetation Dryness Index）以反映地表土壤水分的空间分布特征，以此为基础信息将0.25°的VUA-NASA AMSR-E土壤水分产品降尺度到0.01°分辨率。本算法经NAFE06（The National Airborne Field Experiment 2006）试验地面采样数据验证，降尺度后的土壤水分均方根误差为0.061 m3/m3。\n根据对Ts-NDVI特征空间的深入分析，提出了一个旱情监测的新方法，即三角形空间溢出法（Spill Method）。以往基于Ts-NDVI特征空间计算得到TVDI进行旱情分级用于旱情监测，存在着较大的不确定性。因为通常条件下植被冠层较土壤的温度低，而植被覆盖度改变植被冠层与土壤在遥感像元中的贡献比例是形成Ts-NDVI三角形特征空间的主要原因，而这个过程是线性的，所以在Ts-NDVI特征空间的上边界，即“干边”上，植被仍然是正常生长的。“溢出法”的原理是当植被受水分胁迫出现旱情时，特征点会从上边界“溢出”，成为离散点并形成一个非线性带。用此方法在黑河流域中游张掖绿洲的盈科研究区发现，“溢出”点除一部分混合像元外，受旱主要是在研究区南部的小麦种植区，与野外试验调查结果相一致。 |
| 英文摘要 | Passive microwave radiometry at L-band is the most promising techniques for measuring and monitoring the near-surface soil moisture distribution and dynamics. However, the coarse resolution limits its widely application in the water cycle research at river scale, which requires the middle-high resolution soil moisture data.\nA downscaling method for AMSR-E soil moisture product using MODIS derived TVDI (Temperature Vegetation Dryness Index) as fine resolution information for soil moisture pattern is developed. The Ts-NDVI space is generated by MODIS land surface temperature products (MOD11A1) and MODIS land surface reflectance products (MOD09GA). The TVDI calculated based on this Ts-NDVI space indicates the spatial pattern of soil moisture, and has significantly linear correlation with soil moisture. We calculate the regression equation between TVDI and near-surface soil moisture at the passive microwave scale, and then obtain the soil moisture at MODIS scale using this linearly relationship. The RMSE (Root Mean Square Error) of downscaled 0.01° soil moisture is 6.54% when it's validated by the ground-based soil moisture measurement collected during the National Airborne Field Experiment 2006.\nFurthermore, a new method named spill for monitoring the drought based on Ts-NDVI space is proposed. The formerly method used to monitor the drought based on TVDI level classification is not reasonablehe spill method suggests that points in the Ts-NDVI space triangle would spill out of the top edge when they are under severe drought conditions, and construct a nonlinear area above the triangle. The spill method was applied in the Yineke artificial oasis of the middle reach of the Heihe river basin. Except for the mixed pixels, it is found that the spilled points are mostly in the south of the Yingke oasis where the crops are mainly wheat and dry, which is agree with the field survey results.. The contributions of the thermal radiative of the vegetation canopy and bare soil are different and influenced by the fractional vegetation cover in a remote sensing pixel, which are the reason to construct the Ts-NDVI space triangle. It's a linear process, and so the point at the top edge indicates the vegetations are under normal growth conditions. T |
| 中文关键词 | 土壤水分 ; 降尺度 ; TVDI ; MODIS ; AMSR-E |
| 英文关键词 | soil moisture downscaling TVDI MODIS AMSR-E |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 地图学与地理信息系统 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287035 |
| 推荐引用方式 GB/T 7714 | 曹永攀. 基于MODIS和AMSR-E遥感数据产品的土壤水分降尺度研究[D]. 中国科学院大学,2012. |
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