中文摘要：

于2011年在定西地区开展了观测试验，主要测定了不同水分控制条件下春小麦冠层高光谱反射特征，同步测定了各项生理参数响应。在分析不同水分胁迫下春小麦冠层光谱特征基础上，研究了该地区春小麦冠层光谱对不同水分胁迫的响应特征。结果表明：在水分胁迫下春小麦冠层光谱在可见光区（VIS）和近红外区（NIR）均呈现明显的趋势性变化，随水分减少， VIS光区与短波红外光区（SWIR）反射率都呈增加趋势，而NIR光区反射率呈下降趋势；小麦水分指标冠层等效水厚度（EWTcanopy）比叶片相对含水量（FMC）能够更敏感地体现水分胁迫变化；光谱指数对不同水分胁迫的响应分析表明， WI指数的监测效果较差；反演半干旱区冠层尺度作物水分，红边植被指数与EW Tcanopy相关性最高， P RI指数可反映作物水分胁迫后的光合效率变化，间接反映水分状况，但不适合监测重旱； OSAV I 对土壤调节系数的修订比SAV I 提高了相关性；短波红外波段对水分胁迫的变化响应比较稳定，进一步结合红边波段构建新的水分指数有望提高研究区冠层水分的监测精度。

英文摘要：

The canopy reflectance in different water stresses was measured at the semi-arid agriculture and meteorological station in Dingxi in 2011, and also were measured the biochemistry parameters with the ASD Field Spec spectroradiometer. This work was mainly to analyze the response characteristics for canopy hyperspectral reflectance in different water stresses. The results indicated that the reflectance value in VIS and SWIR increased and the value in NIR decreased with the water stress being from a light to a severe level. The relative water content （FMC） and equivalent water thickness （EWT） were analyzed and the EWT-canopy could indicate that the water changed better than FMC. Eight spectral indices were selected and the relationship between every index and water content was analyzed. Water Index （W I） was not in a good relation to EW T-canopy, and the vegetation indices based on the red edges of NDV I and REP had good relationships with the crop water content defined with EW T-canopy, as well as with the OSAV I and SAV I. And the P RI could bring about the changes of photosynthesis and show the water status indirectly, but it could well show a light instead of a severe drought in the study area. The wave band in SWIR was responed stably with the EW T-canopy and the new index that combined the red edge and SWIR might improve the precision for drought monitoring.