新型扩散云室搭建及其对黄山地区大气冰核的观测研究

本研究利用自行搭建的大气冰核高压静电采样器和静力真空水汽扩散云室,并结合其他大气冰核及气象要素观测仪器,于2011年5～9月及2012年9～10月在黄山三层不同高度上同时进行大气冰核及相关气象要素的连续观测。结果显示:黄山地区总冰核数浓度平均为18.74 L-1,凝结冻结核化冰核数浓度平均为0.79 L-1,凝华核化冰核数浓度平均为0.19 L-1。黄山地区冰核数浓度,随着高度的增加而减小;且存在春季较高、秋季居中、夏季较少的季节变化规律;下午达到一天中的最高值,夜晚达到一天中的最低值;总冰核数浓度较北方少。黄山山顶冰核数浓度随活化温度的升高而减小,随过饱和度的升高而增大,随风速的增强而增大,长期主要由西南风向山顶的输送,且其主要由大粒子来充当。     

Variability of Raindrop Size Distribution during a Regional Freezing Rain Event in the Jianghan Plain of Central China

The characteristics of the raindrop size distribution(DSD) during regional freezing rain(FR) events that occur throughout the phase change(from liquid to solid) are poorly understood due to limited observations. We investigate the evolution of microphysical parameters and the key formation mechanisms of regional FR using the DSDs from five disdrometer sites in January 2018 in the Jianghan Plain(JHP) of Central China. FR is identified via the size and velocity distribution measured from a disdrom...     

以模块化的管理方式促进防震减灾宣传工作

防震减灾宣传是基层地震工作的重要内容之一,本文就如何有效提高防震减灾宣传工作做了初步分析,主要包括层次性和多角度性、针对性和亲和力、宣传工作细化并实施模块化管理几方面,通过事实举例和理性分析,说明模块化管理的必要性和创新性。     

Seasonal and Diurnal Variations of Cloud Systems over the Eastern Tibetan Plateau and East China: A Cloud-resolving Model Study

The seasonal and diurnal variations of cloud systems are profoundly affected by the large-scale and local environments. In this study, a one-year-long simulation was conducted using a two-dimensional cloud-resolving model over the Eastern Tibetan Plateau (ETP) and two subregions of Eastern China: Southern East China and Central East China. Deep convective clouds (DCCs) rarely occur in the cold season over ETP, whereas DCCs appear in Eastern China throughout the year, and the ETP DCCs are approximately 20%?30% shallower than those over Eastern China. Most strong rainfall events (precipitation intensity, PI> 2.5 mm h^?1) in Eastern China are related to warm-season DCCs with ice cloud processes. Because of the high elevation of the ETP, the warm-season freezing level is lower than in Eastern China, providing favorable conditions for ice cloud processes. DCCs are responsible for the diurnal variations of warm-season rainfall in all three regions. Warm-season DCCs over the ETP have the greatest total cloud water content and frequency in the afternoon, resulting in an afternoon rainfall peak. In addition, rainfall events in the ETP also exhibit a nocturnal peak in spring, summer, and autumn due to DCCs. Strong surface heat fluxes around noon can trigger or promote DCCs in spring, summer, and autumn over the ETP but produce only cumulus clouds in winter due to the cold and dry environment.     

2007年12月南京六次雨雾过程宏、微观结构演变特征

利用2007年冬季南京信息工程大学对雾的综合观测资料,包括能见度仪、雨滴谱仪、雾滴谱仪、宽范围颗粒粒径谱仪(WPS)观测资料,并结合地面常规气象观测资料和NCEP(National Centers for Environmental Prediction)再分析资料,分析2007年12月南京六次雨雾过程的宏、微观结构演变特征。结果显示:(1)南京2007年12月的六次雨雾过程主要是受天气系统的影响,以雨中雾为主,最低能见度均大于250 m。雨雾多出现在偏东气流的作用下,南京地区先发生弱降水,空气近饱和,随后受到来自北方的弱冷空气影响,水汽凝结,雾形成。(2)雨雾发生前贴地层多有逆温,雨雾过程中2 m高度与地表温度差由正转为负,逆温消失。但900 hPa以下,雨雾发生前和过程中,都少有逆温层,雨雾结束后均无逆温结构。雨雾前中低层有云,云状为高积云Ac或高层云As及层积云Sc或碎雨云Fn,低云高0.3～2.5 km,雨雾过程中,600 hPa以下都是饱和层,多伴有Fn,低云高度明显下降,雨雾过后,近饱和层仍然有可能存在。雨雾前900 hPa附近有明显的风切变。(3)雨雾形成初期,大粒子(粒子直径D≥10 μm)和小粒子(1 μm相似文献   

Parameterization and Explicit Modeling of Cloud Microphysics: Approaches,Challenges, and Future Directions

Cloud microphysical processes occur at the smallest end of scales among cloud-related processes and thus must be parameterized not only in large-scale global circulation models(GCMs) but also in various higher-resolution limited-area models such as cloud-resolving models(CRMs) and large-eddy simulation(LES) models. Instead of giving a comprehensive review of existing microphysical parameterizations that have been developed over the years, this study concentrates purposely on several topics that ...     

Characteristics of Surface Solar Radiation under Different Air Pollution Conditions over Nanjing,China: Observation and Simulation

Surface solar radiation (SSR) can affect climate, the hydrological cycle, plant photosynthesis, and solar power. The values of solar radiation at the surface reflect the influence of human activity on radiative climate and environmental effects, so it is a key parameter in the evaluation of climate change and air pollution due to anthropogenic disturbances. This study presents the characteristics of the SSR variation in Nanjing, China, from March 2016 to June 2017, using a combined set of pyranometer and pyrheliometer observations. The SSR seasonal variation and statistical properties are investigated and characterized under different air pollution levels and visibilities. We discuss seasonal variations in visibility, air quality index (AQI), particulate matter (PM₁₀ and PM_2.5), and their correlations with SSR. The scattering of solar radiation by particulate matter varies significantly with particle size. Compared with the particulate matter with aerodynamic diameter between 2.5 μm and 10 μm (PM_2.5?10), we found that the PM_2.5 dominates the variation of scattered radiation due to the differences of single-scattering albedo and phase function. Because of the correlation between PM_2.5 and SSR, it is an effective and direct method to estimate PM_2.5 by the value of SSR, or vice versa to obtain the SSR by the value of PM_2.5. Under clear-sky conditions (clearness index ≥0.5), the visibility is negatively correlated with the diffuse fraction, AQI, PM₁₀, and PM_2.5, and their correlation coefficients are ?0.50, ?0.60, ?0.76, and ?0.92, respectively. The results indicate the linkage between scattered radiation and air quality through the value of visibility.     

Relationships between Cloud Droplet Spectral Relative Dispersion and Entrainment Rate and Their Impacting Factors

Cloud microphysical properties are significantly affected by entrainment and mixing processes. However, it is unclear how the entrainment rate affects the relative dispersion of cloud droplet size distribution. Previously, the relationship between relative dispersion and entrainment rate was found to be positive or negative. To reconcile the contrasting relationships, the Explicit Mixing Parcel Model is used to determine the underlying mechanisms. When evaporation is dominated by small droplets, and the entrained environmental air is further saturated during mixing, the relationship is negative. However, when the evaporation of big droplets is dominant, the relationship is positive. Whether or not the cloud condensation nuclei are considered in the entrained environmental air is a key factor as condensation on the entrained condensation nuclei is the main source of small droplets. However, if cloud condensation nuclei are not entrained, the relationship is positive. If cloud condensation nuclei are entrained, the relationship is dependent on many other factors. High values of vertical velocity, relative humidity of environmental air, and liquid water content, and low values of droplet number concentration, are more likely to cause the negative relationship since new saturation is easier to achieve by evaporation of small droplets. Further, the signs of the relationship are not strongly affected by the turbulence dissipation rate, but the higher dissipation rate causes the positive relationship to be more significant for a larger entrainment rate. A conceptual model is proposed to reconcile the contrasting relationships. This work enhances the understanding of relative dispersion and lays a foundation for the quantification of entrainment-mixing mechanisms.     

昌黎井数字化水温资料分析

昌黎井数字化水温具有比较规律的多年变化动态趋势,整理水温资料,分析水温前兆异常变化,得出水温变化机理和映震机理,为今后充分发掘地震前兆信息提供帮助。     

Analysis of the Microphysical Structure of Heavy Fog Ｕsing a Droplet Spectrometer: A Case Study

The microphysical properties of a long-lasting heavy fog event are examined based on the results from a comprehensive field campaign conducted during the winter of 2006 at Pancheng (32.2°N, 118.7°E), Jiangsu Province, China. It is demonstrated that the key microphysical properties (liquid water content, fog droplet concentration, mean radius and standard deviation) exhibited positive correlations with one another in general, and that the 5-min-average maximum value of fog liquid water content was sometimes ...