近30a黔南地区辐射雾和雨雾时空分布特征

利用1991-2020年黔南地区12站逐日最小能见度、降水量、日照时数、云量、气温、相对湿度、风速等气象观测资料,对辐射雾和雨雾进行判定,采用正交函数分解（EOF）、Mann-Kendall突变检验、线性倾向估计等方法分析其时空分布特征。结果表明：黔南地区辐射雾和雨雾时空分布差异较大,辐射雾高发区为平塘、罗甸、龙里,雨雾为独山、都匀、长顺。都匀、龙里、长顺、瓮安、平塘、福泉、荔波、罗甸近10a辐射雾明显减少或雨雾异常增多,次区域特征显著;辐射雾日比雨雾日多42.2%,辐射雾占大雾过程87.1%,雨雾占13.9%,辐射雾主要在夏末至秋冬季,雨雾主要在冬季至初春;辐射雾2011年之后明显减少、雨雾2017年之后急剧陡升,均发生显著突变;辐射雾有9站呈减少趋势,雨雾有8站呈现增加趋势。

Temporal and spatial distribution characteristics of radiation fog and rain fog

Radiation fog and rain fog were determined based on meteorological observation data of 12 stations in Qiannan area from 1991 to 2020, which include minimum visibility, daily precipitation, sunshine duration, cloud cover, air temperature, relative humidity, wind speed and so on.Orthogonal function decomposition (EOF), Mann-Kendall mutation test, linear propensity estimation and other methods were used to analyze the temporal and spatial distribution characteristics of radiation fog and rain fog.The results showed that:The spatial and temporal distributions of radiation fog and rain fog in Qiannan area are quite different.Radiation fog occurs most frequently in Pingtang, Luodian and Longli, while the rain fog occurs most frequently Dushan, Duyun and Changshun.Radiation fog decreased obviously or rain fog unusual increase in recent 10 years in Duyun, Longli, Changshun, Weng "an, Pingtang, Fuquan, Libo and Luodian, which has significant sub-regional characteristics.Radiation fog day is 42.2% more than rain fog day. Radiation fog accounts for 87.1% and the rain fog accounts for 13.9% of the fog process. Radiation fog mainly occur from late summer to winter, and rain fog mainly occur from winter to early spring;Radiation fog decreased significantly after 2012, rain fog increased sharply after 2017, all of which showed a significant mutation.Radiation fog at 9 stations showed a decreasing trend ,while rain fog at 8 stations showed an increasing trend.