黄淮海平原典型农区冬小麦干热风灾害的变化分析——以商丘为例

Changes of dry-hot wind hazard for winter wheat in the typical agricultural areas of Huang-Huai-Hai Plain: A case of Shangqiu

为探明黄淮海典型农区冬小麦干热风灾害发生规律,以商丘为例,利用1963-2012年历年冬小麦生长后期的气象资料,系统分析了近50年冬小麦干热风年平均发生日数分布特征及其对气候变化的响应,探讨了干热风发生次数与冬小麦单产的关系。结果表明:近50年商丘地区冬小麦轻度、重度干热风灾害总体表现为减少趋势,轻度、重度干热风灾害年际变化较大,20世纪60年代干热风危害最严重,20世纪80年代和最近10年干热风危害较轻。1972年干热风发生期日最高气温呈现递增突变(P>0.05),14时风速在1984年前后出现了显著的减小突变(P<0.05),14时相对湿度显著增加,在1981年出现了一次显著的递增突变(P<0.05)。日最高气温、14时风速和14时相对湿度三个气候要素综合作用决定了商丘冬小麦干热风灾害整体上呈递减趋势,其中风速的显著减小对干热风灾害减弱起主要作用。商丘地区干热风的年均发生日数与冬小麦单产呈明显的负相关关系。

Climate change is producing significant impacts on global agricultural production.Climatic variations affect crop production, and tend to be a key constraint of agricultural production, primarily on continuous increase of winter wheat yields worldwide. The great uncertainties in predicting the effects of climate change on wheat production are most likely due to less understanding of the responses of wheat production to extreme climatic factors, e.g.high temperatures, low humidity as well as high wind speed. Dry- hot wind hazard represents one of the main natural disasters for Chinese winter wheat production, especially in the HuangHuai- Hai Plain. However, there still exist great uncertainties of the effects of dry- hot wind hazard on winter wheat production, mainly due to the gaps of long- term observations.Therefore, we selected Shangqiu as the case study area to determine the occurrence regularity of dry-hot wind hazard on winter wheat production in the Huang-Huai-Hai Plain. We analyzed regional meteorological data with daily resolution in the later growth stage of winter wheat during the period 1963- 2012. In accordance with the meteorological industry standards of 'Disaster Grade of Dry-hot Wind for Wheat' by the China Meteorological Administration, we synthetically analyzed the distribution of annual average days of dry-hot wind in winter wheat growing seasons and the associated responses to the climate change. Hence, the relationship between dry-hot wind times and winter wheat yields was examined. The results showed that the annual average days of light and severe dry-hot wind tended to decline in recent 50 years. Great inter- annual variations of light and severe dry- hot wind were observed. The significant interannual variations were related with the corresponding meteorological conditions of temperature, moisture and wind speed. The most serious damages of both light and severe dryhot wind occurred in the 1960 s, while less damages appeared in the 1980 s and the last decade,which could be also explained by the corresponding temperature, moisture and wind speed conditions. From 1963 to 2012, a climatic mutation point of daily maximum temperature was found in 1972(p>0.05). The wind speed at 14:00 and the relative humidity at 14:00 were closely related to the hazard. A climatic mutation point of the wind speed at 14:00 was found around 1984, and climatic mutation of the relative humidity at 14:00 was found in 1981(p<0.05). Daily maximum temperature and wind speed at 14:00 and the relative humidity at 14:00played a major role in the decreasing trend of dry- hot wind disaster, and the significant decrease of wind speed at 14:00 was a main factor in Shangqiu. Dry- hot wind hazard had a strong response to climate change. Yields of winter wheat were negatively correlated with annual average days of dry-hot wind in Shangqiu(p<0.05). In actual practices, great attention should be paid to the defense of dry- hot wind for winter wheat production. Thus, the most effective measures have to be taken to enhance the resistance of winter wheat to dry-hot wind hazard through improving field microclimate condition.