初春雨转雪对冬小麦产量的影响——以河南许昌为例

应用Micaps3天气图资料、卫星云图,对许昌市2014年2月16—18日雨转雪天气过程进行诊断分析,对环流形势、水汽条件、动力、热力特征的分析结果表明:1前期主要是500 h Pa高空槽和700 h Pa切变线影响的稳定性降水,后期是850 h Pa回流冷空气不断补充堆积形成深厚的冷垫,低层偏东气流与中高层槽前的西南暖湿急流交汇形成回流降水形势.高低空的有力配合,冷暖空气的交汇为降水提供了较好的动力条件.冷空气侵入时段、气温下降速度、降水时间,都是初春降水性质发生改变的关键点.2这次雨转雪天气过程对越冬作物小麦生长特别有利,可以冻死土地中的害虫和虫卵,大大降低来年麦蜘蛛、吸浆虫,蚜虫等病虫害的发生几率,也对冬小麦纹枯病,赤霉病的滋生和蔓延起到抑制作用,使小麦越冬基数减小,提高了2014年冬小麦的产量.

Influence of Early Spring Rain to Snow Weather on the Yield of Winter Wheat--Taking Xuchang,Hennan Province as an Example

In this paper, Micaps3 weather map data, satellite images of Xuchang City in February 16-18, 2014, the rain turning snow weather process diagnostic analysis of circulation patterns, water vapor, power, thermal characteristics was carried out. The results showed as follows. （1）In the early stage, 500 hPa upper trough and 700 hPa mainly affect the stability of the shear line precipitation, while in the later stage, 850 hPa reflow cold air is constantly replenished and stacked to form a deep cold pad, southwest of warm low-level easterly winds and the jet stream intersected and formed the high-level trough reflux precipitation situation. High and low altitude with a strong, cold air intersection provides better dynamic conditions for precipitation. The cold air invasion period, the temperature dropped speed, precipitation time are the key points of the change in precipitation in early spring. （2）The process for the rain to snow weather winter wheat crop grown is particularly advantageous, which can help kill pest and its eggs in the land. It can also reduce the bad effects of wheat spider midge, aphids and other pests greatly, which is good for restraining the occurrence of gibberellic disease and banded sclerotial blight. In this way, the yield of winter wheat in 2014 is improved.