2000—2012年江西省三类区域性大雾时空分布及影响因素特征

Characteristics of spatiotemporal distribution and influence elements of three kinds of regional heavy fog in Jiangxi province from 2000 to 2012

利用中国气象局下发的2000—2012年常规地面观测资料、探空资料以及江西省GD05报资料,对比分析了江西省三类区域性大雾的时空分布、天气形势和主要气象要素特征。结果表明:2000—2012年江西省发生区域性大雾共259例,辐射雾最多。辐射雾主要发生于深秋至次年初春;平流辐射雾主要发生于冬季;平流雾主要发生于冬末初春,夏季不曾出现。江西省区域性大雾总体呈"中间多、赣北北部和赣东南少"的分布特征。辐射雾单次发生面最广,平流雾发生面最窄。江西省持续性区域大雾以辐射雾最为常见。平流辐射雾的逆温强度最大,平流雾最小。辐射雾逆温层结主要在1000 h Pa附近及以下,上干下湿明显;平流辐射雾逆温层结可为多层逆温,在1000 h Pa以下和925 h Pa附近均可出现逆温、高湿区;而平流雾湿层深厚,逆温层结主要在925 h Pa附近。辐射雾时,江西地面为均压场,低层为明显反气旋环流控制;平流辐射雾时,江西多处于地面小高压后部偏南气流中,低层表现为宽广的偏南气流;平流雾时,雾区处于地面低压倒槽附近、925 h Pa切变线以南2个纬距内的偏南暖湿气流中。

Based on the conventional surface meteorological observational data and sounding data obtained from Chinese Meteorological Administration （CMA） as well as the GD05 numerical forecasting data over Jiangxi province from 2000 to 2012, the characteristics of spatiotemporal distribution, weather situation and major meteorological parameters of three kinds of regional heavy fog in Jiangxi province were comparatively analyzed. The results show that a total of 259 regional heavy fog events occur in Jiangxi province from 2000 to 2012, and the radiative fog events occur most frequently. The radiative fog events mainly occur from late autumn to early spring, and the advective-radiative fog events mainly occur in winter. The advection fog events usually occur in late winter and early spring but not in summer. Overall, the spatial distribution of regional heavy fog in Jiangxi province is charac- terized by a high frequency in the middle region and low frequency in the northern and southeastern regions. A radiative fog event can cover a wide area, while the advection fog events usually occur within a narrow area. Among the regional heavy fog events in Jiangxi province, the radiative fog events are the most common type. The temperature inversion intensity is the strongest for advection-radiation fog events and is the weakest for advection fog events. The temperature inversion layer mainly exists near and under 1000 hPa level, and dry air at upper levels and wet air at lower levels. Multi-inversion layers can be found in advection-radiation fog and occur under 1000 hPa level and near 925 hPa level with high moist area. The advection fog has deep moist layer and with the thermal in- version layer near 925 hPa level. As a radiation fog event occurs, the surface pressure field is uniform and the low- er levels are controlled by an anticyclone circulation over Jiangxi province. During advection-radiaiton fog events, Jiangxi province is mostly controlled by the southerly flows at the back of weak high pressures, and a wide souther- ly current prevails at the lower levels. When an advection radiation fog occurs, the foggy area is located near the surface depression inverted trough and is controlled by the warm and moist southerly flows within 2-latitudes distance to the south of the shear line at 925 hPa.