Abstract:

Remote sensing data has the characteristics of spatial continuous imaging and repeated sampling. It can be used for monitoring regional wheat jointing stage, and then provide basic data for studying and monitoring of winter wheat late freezing injury. Taking winter wheat planting area in Henan Province as studying area, this paper firstly established the equation between the accumulated temperature and the cumulative value of land surface temperature (LST). And the LST data was provided by remote sensing. On this basis, the accumulated temperature demand quantity of winter wheat from turning green to jointing was transformed into the accumulated LST demand quantity. Then starting from turning green date, the date when the accumulated LST value reached its demand quantity from turning green to jointing was calculated by using the Terra/MODIS LST data product MOD11A2. And the date is the jointing stage start time. The results showed that the wheat jointing start date concentrated in late March to early April. The annual temperature differences could cause significant fluctuations in jointing start time. From the view of spatial distribution, except for Xinyang area, the jointing start time of winter wheat from south to north gradually postpone in Henan Province. The error between the monitoring results and the observation values could be controlled within 5 d in most cases, which showed that remote sensing data, LST, together with the accumulated temperature model could be used to monitor the jointing stage.

Key words: winter wheat, jointing stage, accumulated temperature, land surface temperature, remote sensing monitoring

摘要：

遥感数据因其空间连续成像和重复采样的特点，可用于区域尺度小麦拔节期监测，为冬小麦晚霜冻害监测研究提供基础数据。以河南省冬麦区为研究区，建立气象台站获取的积温与遥感获取的陆面温度（LST）累积值间的关系方程，在此基础上，将冬小麦返青-拔节期间的积温需求量转化成累积LST需求量，利用Terra/MODIS LST数据产品MOD11A2，从返青日期开始求算累积LST值达到返青-拔节期间的累积LST需求量的日期，获得拔节期开始时间。结果表明，河南省小麦拔节期开始日期集中在3月下旬至4月上旬；年际间同期气温差异会引起小麦拔节期开始时间显著波动；空间分布上，除信阳地区外，河南省冬小麦拔节期开始时间大致由南到北逐渐推迟；小麦拔节期开始时间监测值与观测值之间的误差大部分能控制在5 d之内，说明利用LST遥感数据结合积温法可以监测冬小麦的拔节期。

关键词: 冬小麦；拔节期；积温；陆面温度；遥感监测