2015年2月20—22日通辽市大雪天气过程分析

文章为了探究通辽地区大雪天气的气象要素演变特征和影响因素以及形成原因,利用常规气象资料、自动气象站等数据,对2015年2月20—22日大雪天气过程进行分析,结果表明:有利的大尺度环流、有利的层结条件、充沛的水汽条件、冷暖低空急流的汇合、高低空急流的耦合、强烈的上升运动及高空急流的动量下传作用是激发此类灾害性天气的关键因素。这些指标能够为今后的大雪预报提供参考依据,对大雪预报准确率的提高起至关重要的作用。     

1998年4月14～15日强沙尘暴过程分析

利用卫星云图，数值预报产品以及常规气象资料对1998年4月14－15日发生在我国西部地区的沙尘暴天气进行了分析，指出本次过程发生在大气环流形势调整过程中，是由斜压槽及冷锋触发的。也重点分析了两个强沙尘暴中心的成因，发现第一个强沙尘暴区是由加强的冷锋云带造成的，而第二个强沙尘暴区是由三条云带共同作用造成的。强沙尘暴区位于高空急流出口区右侧、500hPa正涡度中心下风方和次级反环流的上升区内，并用动力气象学原理做了初步讨论，为预报沙尘暴提供了新的依据。     

A Study on a Snowband Associated with a Coastal Front and Cold-Air Damming Event of 3-4 February 1998 along the Eastern Coast of the Korean Peninsula

A 24-h simulation with the Advanced Regional Prediction System (ARPS) nonhydrostatic model is performed for the heavy snowfall event of 3–4 February 1998 along the eastern coast of Korean Peninsula; the results are used to understand the snowfall process, including why the precipitation maxima formed along the Yeongdong coastal region rather than over the mountain slope and ridge top during. The numerical simulation with a 4-km horizontal grid spacing and 43 levels reproduces very well the narrow snowband located off the eastern Korean coast, away from, instead of over, the Yeongdong coastal mountain range. The general evolution of the snowband agrees quite well with radar observations, while the water-equivalent precipitation amount agrees reasonably well with radar precipitation estimate. The simulation results clearly show that the snow band developed due to the lifting by a coastal front that developed because of the damming of cold air against the eastern slope of the coastal mountain range. The damming was enhanced by the advection of cold air by a low-level mountain-parallel jet from the north, formed due to geostrophic adjustment as the on-shore upslope air was decelerated by the mountain blocking. As the onshore flow weakened later due to synoptic-scale flow pattern change, the cold front propagated off shore and the precipitation dissipated.     

The temperature dependent,infrared absorption cross-sections for the chlorofluorocarbons: CFC-11, CFC-12, CFC-13, CFC-14, CFC-22, CFC-113, CFC-114, and CFC-115

The infrared absorption cross-sections for eight commonly used halogenated methanes and ethanes have been measured as a function of temperature from 203 to 293 K. High resolution spectra (0.03 cm^-1) have been used to derive integrated band strengths and peak cross-sections associated with the spectral features in the infrared region from 600 to 1500 cm^-2. The values obtained in this study are compared to those from previous reports, and recommendations are made for uses in atmospheric sensing and radiative energy transfer models. The observed temperature dependence in the spectral features is also discussed.