温室春石斛兰花期与外观品质温度调控模型

低温春化处理是保证春石斛兰开花和外观品质的关键技术.针对我国温室春石斛兰生产中普遍存在的因春化阶段温度控制不当,导致不能及时开花和外观品质下降或成为盲花的问题,文中通过不同定植期和不同温度春化处理实验,定量分析了温度对春石斛兰春化进程和产品外观品质的影响,并进一步建立了温室春石斛兰花期与外观品质温度调控模型.用独立的实验资料对模型进行检验,结果表明,模型对不同温度条件下春石斛兰完成春化阶段所需天数、到达采收所需天数和外观品质的预测效果较好.模型对各个生育时期(从春化开始到花芽生长.花芽生长到现蕾,现蕾到始花,始花到采收期)预测值与实测值之间的决定系数R。为0.97,回归统计标准误RMSE分别为1 d(从春化开始到花芽生长)、1.58 d(花芽生长到现蕾)、4 d(现蕾到始花)、6.52 d(始花到采收期).采收时单株花蕾节数与单株花蕾数预测值与实测值之间的R~2分别为0.81和0.84,RMSE分别为0.62/plant和0.65/plant.对不同白天和夜间温度控制目标下,春石斛兰完成春化阶段所需的天数、到达采收所需天数和外观品质的模拟分析结果表明,当夜间温度为9～14℃,白天温度为18～28℃时,春石斛兰产品可以最快上市且外观品质最优.文中建立的模型可以为温室春石斛兰花期与外观品质的温度精准调控提供理论依据和决策支持.     

The responses of East Asian Summer monsoon to the North Atlantic Meridional Overturning Circulation in an enhanced freshwater input simulation

We investigated the response of the East Asian Summer Monsoon （EASM） to a weakened Atlantic Meridional Overturning Circulation （AMOC） and its mechanism in an enhanced freshwater input experiment （FW） by using a fully-coupled climate model. The response was a weakened EASM and the mechanisms can be explained as follows. The simulated weakened AMOC resulted in a drop in sea surface temperature （SST） in the North Atlantic （NA） and, correspondingly, an anomalous high sea level pressure （SLP） over the North American regions, which in turn increased the northeast surface winds across the equator in the eastern tropical Pacific （ETP）. The anomalous northeast winds then induced further upwelling in the ETP and stronger air/sea heat exchange, therefore leading to an anomalous cooling of the eastern tropical sea surface. As a result, the climatologic Hadley Circulation （HC） was weakened due to an anomalous stronger sinking of air in the ETP north of the equator, whereas the Walker Circulation （WC） in the western tropical Pacific （WTP） north of the equator was strengthened with an eastward-shifted upwelling branch. This feature was in agreement with the anomalous convergent winds in the WTP, and led to a weakened EASM and less East Asian summer precipitation （EASP）. Furthermore, comparison with previous freshwater experiments indicates that the strength of EASP could be influenced by the magnitude of the added freshwater.