摘要
基于近红外-红波段特征空间的垂直干旱指数(PDI)在表征土壤水分时精度还有待于提高。为提高PDI对土壤水分的敏感性,基于短波红外和红边波段对作物水分胁迫响应更为敏感这一事实,考虑Sentinel 2卫星数据的短波红外、红边1、红边2和红边3波段,分别与红波段构建特征空间,提出新的土壤水分监测指数(分别记为SPDI、R1PDI、R2PDI和R3PDI),改进PDI,并基于冬小麦全生育期的土壤湿度实测数据评价构建的指数。结果表明,与PDI相比,新建立的指数在表征土壤墒情方面表现良好,与实测土壤湿度的负相关性更强。冬小麦播种、越冬、拔节和灌浆期的土壤墒情最优表征指数分别是SPDI、R1PDI、R2PDI和R2PDI,这些指数与实测数据的相关系数绝对值|r|分别为0.79、0.74、0.70和0.61,相关性极显著,均强于PDI与冬小麦播种、越冬、拔节和灌浆期实测数据的相关性。Sentinel 2数据的短波红外、红边1和红边2波段更适合构建水分响应指数,与红波段构建的新型指数在土壤墒情监测方面具有潜力。
The perpendicular drought index(PDI),which was constructed in the previous study based on the near infrared(NIR)-red band reflectance feature space to characterize the agricultural drought,is not very sensitive to the soil moisture and its accuracy needs to be improved.In order to enhance the sensitivity and improve the accuracy of PDI to soil moisture,we tried to modify PDI.The shortwave infrared(SWIR)and red edge bands were more sensitive than NIR band to the change of water content in vegetation and soil moisture.This fact inspired us to consider the SWIR and three red edge bands of Sentinel 2 satellite data when constructing the feature space with the red band.Based on the SWIR-red,red edge 1-red,edge 2-red and red edge 3-red reflectance feature space,we proposed the new soil moisture monitoring indexes(labeled as SPDI,R1PDI,R2PDI and R3PDI,indicating using the SWIR,red edge 1,red edge 2 and red edge 3 bands to replace the NIR band,respectively)to improve PDI.The proposed indexes were evaluated using the measured in situ data of soil moisture recorded with the latitude and longitude on October 26,December 25 in 2020,April 16,May 26 in 2021,when was the sowing,overwintering,jointing and filling stages of winter wheat,respectively.The results showed that the established indexes performs better in characterizing soil moisture,showing the higher negative correlation with the measured soil moisture compared with PDI.The optimal characterization indexes of soil moisture in the sowing,overwintering,jointing and filling stages of winter wheat were SPDI,R1PDI,R2PDI and R2PDI,respectively.The absolute value of correlation coefficients between SPDI,R1PDI,R2PDI and R2PDI and the measured data were 0.79,0.74,0.70 and 0.61,respectively,passing the 0.01 level significance test,while that were 0.72,0.66,0.41 and 0.38 for PDI in the sowing,overwintering,jointing and filling stages of winter wheat.The improvement effect of the established indexes was especially obvious for the jointing and filling stages,when the vegetation co
作者
陈媛媛
幸泽峰
焦为杰
胡华浪
游炯
祝龙
CHEN Yuan-yuan;XING Ze-feng;JIAO Wei-jie(Big Data Development Center,Ministry of Agriculture and Rural Affairs,Beijing 100125;Academy of Agricultural Planning and Engineering,Ministry of Agriculture and Rural Affairs,Beijing 100121)
出处
《安徽农业科学》
CAS
2023年第10期186-192,共7页
Journal of Anhui Agricultural Sciences
基金
国家重点研发计划项目“智慧农牧关键技术集成与中蒙协同创新示范园研究”(2021YFE0102000)
农业农村部规划设计研究院自主研发项目“‘3S’技术支持下的自主可控精准农业体系研究”(ZZYFXKFZ201904)。
关键词
土壤湿度
垂直干旱指数
短波红外
红边
Soil moisture
Perpendicular drought index
Shortwave infrared
Red edge
