2020年河北唐山5.1级地震前震源参数变化

利用谱分析方法对河北省测震台网2016年1月—2020年7月唐山老震区(117.5°～119.5°E,39°～41°N)85次M_L≥2.5地震进行震源参数分析,发现该时段唐山老震区应力降范围在0.1～10.3MPa,主要集中在0.1～1.0MPa,其中应力降小于2MPa的地震占81%。当2.5≤M_L≤3.5时,应力降、拐角频率与震级之间无明显的对应关系;ML≥4.0地震较少,但应力降有随震级增大而增大的趋势,拐角频率有随震级增大而减小的趋势。2019年12月5日河北丰南M4.5地震和2020年7月12日唐山M5.1地震之间发生了 7次M_L≥2.5地震,震级范围为2.5≤M_L≤2.8,提取该震级范围的震源参数进行时空分析,发现唐山M5.1地震前有2次明显的高应力降事件,2次高应力降事件呈现出应力降数值高、拐角频率高、震源尺度小的特点,表明单位体积所释放能量较多。2次高应力降事件均发生在唐山M5.1地震震中17km范围内,可能是唐山M5.1地震前震源区构造应力较高的一个标志。     

生物乙醇生产及纤维素酶的开发进展

随着石化燃料由短缺变成枯竭,能源危机是人类面临的共同问题。寻找新的能量来源关系到经济的可持续发展乃至人类的生存问题,生物乙醇作为一种可再生的、经济上可承受的,并且对环境安全的能源物质将逐渐成为石油的替代品。提高纤维素酶的产量,降低纤维素酶的成本成为提高纤维素生产生物乙醇的市场的竞争力的关键因素。该文从生物乙醇的产业发展和纤维素酶的开发进展进行综述,为今后生物乙醇生产产业的提升、纤维素酶工程菌的开发提供基础。     

Distribution of the Molecular Gas Around SN 1572

The early-stage structure and evolution of a supernova remnant (SNR) depends largely on its ambient interstellar medium, so the interstellar medium becomes the valid probe for investigating the evolution of SNRs. We have observed the ¹²CO (J = 1 − 0) line emission around the remnant of SN 1572 with the 13.7m millimeter-wave telescope at the Qinghai Station of PMO, in order to investigate the distribution of the CO molecular gas around SN 1572 and provide some observational basis for studying the relationship of SN 1572 with its ambient molecular gas and the evolution of this SNR. The observed result indicates that the molecular gas in the velocity range of V_LSR = −69∼ −58 km/s is associated with SN 1572, and this velocity component comes from a large-scale molecular cloud. The molecular gas is distributed along the periphery of the radio shell, continually but not uniformly, and forms a semi-closed molecular shell around the SNR. The enhanced emission exists in its whole eastern half, especially the CO emission is strongest on the northeastern edge. At the emission peak position, the spectral line exhibits a broadened velocity feature (>5 km/s). Combining with available observations in the optical, infrared, X-ray and other wavebands, it is demonstrated that the fast shock wave and ejecta are expanding into the molecular gas on the northeastern edge, and interacting with the dense gas. This interaction will have an important influence on the future evolution of SN 1572.     

Heat flux apportionment to heterogeneous surfaces using flux footprint analysis

Heat flux data collected from the Baiyangdian Heterogeneous Field Experiment were analyzed using the footprint method. High resolution （25 m） Landsat-5 satellite imaging was used to determine the land cover as one of four surface types： farmland, lake, wetland, or village. Data from two observation sites in September 2005 were used. One site （Wangjiazhai） was characterized by highly heterogeneous surfaces in the central area of the Baiyangdian： lake/wetland. The other site （Xiongxian） was on land with more uniform surface cover. An improved Eulerian analytical flux footprint model was used to determine “source areas” of the heat fluxes measured at towers located at each site from surrounding landscapes of mixed surface types. In relative terms results show that wetland and lake areas generally contributed most to the observed heat flux at Wangjiazhai, while farmland contributed most at Xiongxian. Given the areal distribution of surface type contributions, calculations were made to obtain the magnitudes of the heat flux from lake, wetland and farmland to the total observed flux and apportioned contributions of each surface type to the sensible and latent heat fluxes. Results show that on average the sensible heat flux from wetland and farmland were comparable over the diurnal cycle, while the latent heat flux from farmland was somewhat larger by about 30-50 W m-2 during daytime. The latent and sensible fluxes from the lake source in daytime were about 50 W m-2 and 100 W m-2 less, respectively, than from wetland and farmland. The results are judged reasonable and serve to demonstrate the potential for flux apportionment over heterogeneous surfaces.     

2009年7月4-6日北海地区暴雨过程初步分析

从大气环流特点、暴雨的触发条件和水汽条件等方面对2009年7月4-6日北海地区暴雨过程进行分析,找出影响暴雨发生发展的水汽条件和物理机制。     

卢氏县2009年5月27日暴雨成因分析

统计分析了影响卢氏县降水的天气系统,结果表明:冬春季节可能造成降水的天气系统有西风槽、低层东北风和高空西南气流相结合、高空西南气流和地面倒槽相结合等,夏秋季节有西风槽、东西向切变线、南北向切变线、黄淮气旋、华北冷涡、高空强冷平流区、偏南气流等.华北冷涡、高空强冷平流影响时,产生冰雹的可能性很大;西风槽、东西向切变线、南北向切变线、黄淮气旋、偏南气流影响时,有利于暴雨产生.     

“黄蜂”边界层风速分析—— 台风平均风速的时距选取与强度估计

通过对热带风暴(TC)"黄蜂"登陆的一次边界层观测所得到风速资料的分析计算,取得不同时距下平均风速序列.比较不同时距选取时登陆TC的平均风速、风向和台风强度,发现1 min平均比10 min平均水平最大风速大25.30%,风向变化不大,TC强度指数1 min与10 min相差2%～4%.时距选取较小时,TC平均风速和强度变大,所测得风速区域也变大,而风向与时距的选取没有明显关系.只是在阵风变化比较大的情况下选取小的时距可以更好的表示这种特征.所以时距选取需要对所研究问题的需要进行分析,对不同的问题选取不同的时距以得到更好的结果.     

利用太阳光度计反演郑州地区水汽含量

利用CE-318型太阳光度计936 nm波段的太阳辐射观测资料,采用改进的Langley法反演了郑州地区大气柱水汽含量,并分析了大气柱水汽含量与地面水汽压之间的关系。结果表明:郑州地区大气柱水汽含量的季节变化:夏季>秋季>春季>冬季,日变化为早晚低,中午高;郑州地区大气柱水汽含量与地面水汽压之间存在着良好的线性关系。     

淳安杨梅岛"6·23" 雷击事件的调查分析

目前,对于船舶及船上人员的雷电防护措施极其缺乏,国家相关规范也没有明确的规定和指导,安全隐患极大.本文通过对一起船舶雷击事件的调查,从地理环境、天气情况和船只结构等方面,分析此次雷击事件的成因,并提出了一些船舶雷电防护措施.     

海南菠萝反季节种植的气候特征分析

统计近20年海南省万宁市的菠萝种植情况,发现其产量的高低与气候密切相关,从海南各地的降水、温度、风等具体气象因子入手,分析海南菠萝反季节种植的气候特征,并以此进行分区.