宁夏1981—2010年大气能见度变化特征及气象因子分析

Analyses on Variation Characteristics of Atmospheric Visibility and Meteorological Factors in Ningxia during 1981—2010

利用1981—2010年宁夏25个区域观测站的能见度、相对湿度、日照时数、温度、风速等常规观测资料,分析宁夏北部、中部、南部3个区域能见度及气象因子的月、季变化和年际变化特征,并对能见度与气象因子的相关关系进行探讨。结果表明:(1)宁夏3个区域能见度均有明显的月、季变化和年际变化特征,各区域能见度月变化均为单峰结构;各区域能见度均为夏季最好,北部和中部区域冬季最差,南部区域春季最差;近30 a,北部区域能见度表现为波动增加趋势,中部和南部区域均为明显降低趋势。(2)各区域气象因子月变化也为单峰结构;相对湿度秋季最好,春季最差;日照时数夏季最长,日照时数最短的季节各不相同;冬季温度最低,夏季温度最高;春季平均风速最大;近30 a各区域相对湿度和日照时数均未表现出明显的年际变化趋势,仅中部区域的温度、北部和中部区域的风速增加趋势较为显著。(3)各区域能见度与相对湿度均表现为非常显著的负相关关系;能见度与温度表现为显著或非常显著的正相关关系;除春季南部区域外,能见度与日照时数也表现为非常显著的正相关关系;能见度与风速的相关关系比较复杂。

The characteristics of visibility and meteorological factors in monthly,seasonal and annual of Ningxia northern,central and southern areas are studied based on the data of visibility,relative humidity,sunshine hours,temperature and wind speed of 25 regional observation stations from 1981 to 2010.The results show that the visibility of these three regions has obvious monthly,seasonal and annual characteristics and the monthly changes of visibility in each region are all single peak.Visibility in summer is the best in all regions and the worst in winter of the north and central.But visibility of the south is the worst in spring.Near 30 a,visibility in the northern region shows increased fluctuation,while that in the central and southern regions is significantly decreased.The monthly variation of regional meteorological factors is also single peak.In autumn,the relative humidity is the best and the worst in spring.The seasons with the shortest sunshine hours are different in these three parts,while those with the longest sunshine hours are the same in summer.The temperature is the lowest in winter and the highest in summer with the highest average wind speed in spring.The relative humidity and sunshine hours of nearly 30a show no obvious annual variation trend,but the temperature in the central region and the wind speed in the northern and central regions increase significantly.The visibility and relative humidity in all regions have a significant negative correlation.Visibility and temperature have a significant positive correlation.Visibility and sunshine hours also have a significant positive correlation except in the southern region in spring.The correlation between visibility and wind speed is complex.