冬小麦田午时冠层温度与气温和地温的关系

Relationships Among Wheat Surface Temperature, Air Temperature and Surface Ground Temperature at Noon in the Wheat Fields

  • 摘要: 基于野外实测数据,分晴日、阴日及不区分阴晴3种情况,研究了湿润与较干冬小麦田午时冠层温度、气温和地温间的定量关系。结果表明:湿润麦田晴日使用气温预测冠温效果最好,基于最终模型估算冠温的平均误差仅1.03℃,标准差为1.26℃。较干麦田晴日与阴日用地温估算冠温效果最佳,基于最终模型估算冠温的平均误差分别为1.64,1.54 ℃;其估算冠温的标准分别为2.05,1.89℃。用本文统计建模法预测结果的误差低于目前用NOAA影像反演冠温时2~3℃的均方根误差。研究结果也说明使用气温和地温预测麦田冠温是切实可行的。这就为冠温数据的获取提供了廉价有效的新方法;同时也使利用遥感影像与地面气象站常规观测资料相结合的方法,在较大的区域范围内进行冬小麦需水预测成为可能。

     

    Abstract: The quantitative relationships among wheat surface temperature (TL), air temperature (Tɑ) and siol-surface temperature (TS) at noon in the wet and dry wheat fields were investigated based on field data. The data collected was divided into a training set and a validation set and three types of weather were categorized as clean, cloud and both. The results show that for the wet wheat field in clear days, the best results could be achieved using Tɑ to estimate TL; based on the final model, the average estimated error is 1.03oC and the RMS of estimated TL is 1.26 oC. For the dry wheat field in the clear or cloud days, TL could be well estimated with TS. The average estimated errors of the final model are 1.64 and 1.54 oC respectively and the RMS of estimated TL are 2.05 and 1.89 oC respectively. The RMS errors achieved are generally lower than those derived from NOAA digital images (2—3 oC). The results of this research show that it is feasible to forecast wheat surface temperature with air temperature and soil-surface temperature, too. It provides a new cheap effective means to get wheat surface temperature; at the same time, it is also possible to combine satellite image data with measured data from ground weather stations to predict the water requirement of winter over a larger region.

     

/

返回文章
返回