四川巴中地区38年来气候变化特征分析

利用1971—2008年巴中地区4个站点的地面常规观测资料和滑动平均、MK法及MHF小波分析等统计诊断方法,分析了该地区降水和温度的年际、年代际的气候变化特征。结果表明：巴中地区的年均气温总体上表现出暖→冷→暖3个阶段,并呈现出8年的准周期变化特征;冬春气温的年代际变化显示出暖→冷→暖3个阶段性特征,而夏秋气温的年代际变化则显示出暖→冷→暖→冷4个阶段性特征。巴中地区的年降水量呈现出减少的趋势,递减率为13．813mm／10年;春季降水量低于全国的春季平均水平,夏、秋季平均降水量均高于全国的平均水平,且占到全年降水量的80％以上。巴中地区的年降水量存在较为显著的2年和6年的准周期变化,降水量增加和减少的突变较多显示出其复杂性。春、夏、秋三季的降水量有随温度升高而下降的趋势,而冬季的降水量有随温度的升高先增多后减少的趋势。巴中气候特征的分析对巴中农业区划和生产安排有其重要意义。     

Picophytoplankton abundance and community structure in the Philippine Sea, western Pacific

Flow cytometric determinations of the abundance distribution and community structure of picophytoplankton (i.e., Prochlorococcus spp., orange fluorescence Synechococcus spp. and picoeukaryotes) were used for samples taken from the Philippine Sea in the western tropical Pacific Ocean from September to October of 2004. A fluorescence probe was employed to detect Chlorophyll a (Chl a). Abundances of Prochlorococcus spp., orange fluorescence Synechococcus spp. and picoeukaryotes ranged from 0.1 to 58×10³ cells ml^?1, 0.38 to 17×10² cells ml^?1 and 0.42 to 26×10² cells ml^?1, respectively. Synechococcus spp. and picoeukaryotes co-occurred in relatively shallow water with the maximum abundance observed at 50 to 70 m depth, while Prochlorococcus spp. only occurred in the 70 to 200 m layer. Prochlorococcus spp. was the dominant picophytoplankton population in terms of abundance and biomass. The cell size and carbon biomass content were estimated for the three picophytoplankton groups. In addition, among the three groups of picophytoplankton, the relative contribution of red fluorescence to the total red fluorescence varied with depth. The fluorescence and light scatter properties of individual cells indicated that in the upper 100 m layer, picoeukaryotes were a major contributor to total red fluorescence, while at the depth below 100 m, Prochlorococcus spp. and Synechococcus spp. made an important contribution to the total red fluorescence.     

Impact of microzooplankton and Calanus sinicus (Brodsky, 1962) on phytoplankton in the Yellow Sea during early summer

Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a (Chl-a) levels. The Chl-a growth rates (k) ranged from 0.60–1.67 d⁻¹, while microzooplankton grazed the Chl-a at rates (g) of 0.29–0.62 d^t-1. The addition of C. sinicus enhanced the Chl-a growth rate (Z) by 0.004–0.037 d⁻¹ ind.⁻¹ L. C. sinicus abundance ranged from 84.1–160.9 ind. m⁻³, which occupied 90.7%–99.1% of the copepod (>500 μm) population. The in-situ increase in phytoplankton by C. sinicus community was estimated to be 0.000 4–0.005 9 d⁻¹. These results showed that microzooplankton were the main grazers of phytoplankton, while C. sinicus induced a slight increase in the levels of phytoplankton.     

Metamorphosis of Magnetospirillum magneticum AMB-1 cells

Magnetospirillum magneticum strain AMB-1 belongs to the family of magnetotactic bacteria. It possesses a magnetosome chain aligning, with the assistance of cytoskeleton filaments MamK, along the long axis of the spiral cells. Most fresh M. magneticum AMB-1 cells exhibit spiral morphology. In addition, other cell shapes such as curved and spherical were also observed in this organism. Interestingly, the spherical cell shape increased steadily with prolonged incubation time. As the actin-like cytoskeleton protein MreB is involved in maintenance of cell shapes in rod-shaped bacteria such as Escherichia coli and Bacillus subtilis, the correlation between MreB protein levels and cell shape was investigated in this study. Immunoblotting analysis showed that the quantity of MreB decreased when the cell shape changed along with incubation time. As an internal control, the quantity of MamA was not obviously changed under the same conditions. Cell shape directs cell-wall synthesis during growth and division. MreB is required for maintaining the cell shape. Thus, MreB might play an essential role in maintaining the spiral shape of M. magneticum AMB-1 cells.     

西藏地区雪灾等级评估研究

建立了基于距离函数的雪灾等级评估模型,采用此模型对1979-2013年西藏地区39个站点筛选出的370次雪灾个例进行等级评估。结果如下：一级和二级雪灾占绝大多数,三、四级雪灾出现的次数相对较少。春季发生雪灾的次数最多,其次为冬季,夏季只有9次一级雪灾发生。1979-2013年,三级雪灾出现的次数在减少。20世纪90年代以前三级雪灾多发生在冬季,以后三级雪灾多发生在春季。四级雪灾在20世纪90年代发生的次数最多,且持续时间较长,大多发生在冬季,21世纪以来有所减少,雪灾发生在秋季和冬季的次数相当。     

1971-2010年青藏高原冬季降雪气候变化及空间分布

利用青藏高原55个气象站1971-2011年冬季（12月-翌年2月）逐月降雪量资料分析了冬季降雪的气候特征,得到高原冬季降雪总体上呈现东部和南部多、西北部和雅鲁藏布江中段少雪的分布特征,相对变率分布与降雪的分布几乎相反且变率大,以30°N为界高原降雪存在南北反相的变化趋势即北部降雪有所增加而南部减少.用旋转经验正交函数REOF结合相关分析进行降雪分区的基础上,重点分析了近40 a来高原降雪的演变特征和长期气候趋势.结果表明：降雪分布清楚地反映了高原的地理特征和气候特点,即高原南部迎风坡、冷暖气流交汇处降雪多,而背风坡、北部降雪少;近40 a降雪呈现“少-多-少”趋势,1980-1990年代期间降雪明显偏多,大约1970年代中期发生了由少雪到多雪的突变现象,其中南部2个区分别在2007年和1988年出现了降雪减少的突变现象;降雪具有显著的准14 a年代际变化和准8 a周期变化,且存在年代际特征.     

四川盆地区表层土壤湿度时空变化特征分析

分析常年土壤干湿状况及其影响因子,是监测评价四川盆地区土壤水分变化的基础,有利于农业干旱防灾减灾.利用四川盆地区农业气象站近17年0～20cm的逐句土壤湿度观测资料,运用旋转正交函数分解(REOF)、相关分析、趋势倾向率分析等方法,对四川盆地区表层土壤相对湿度的时空变化特征进行分析,并分区域选取代表站建立表层土壤湿度与气温、降水量、日照时数的多元回归方程.结果表明,盆地表层土壤相对湿度空间分布大致是从南到北逐渐减小;年际变化呈现弱的上升趋势;常年季节变化呈双峰型特点,秋季高,春季低,夏季波动明显,初夏高盛夏低;表层土壤干湿状况总体呈现出冬春季相对偏干、夏秋季相对偏湿的季节变化.盆地表层土壤湿度变化与气温、日照显著负相关,与降水显著正相关性,气温、日照、降水因子分别对盆地东北部、中南部、西北部表层土壤湿度变化影响大.     

发电厂建（构）筑物沉降监测数据分析

发电厂设备较多,结构复杂,危险性较大,必须对其建（构）筑物进行沉降和变形监测。以湛江奥里油发电厂为例,在沉降观测的过程中,根据各个建筑物的沉降情况,进行了沉降趋势分析,针对湛江奥里油电厂建筑物沉降的特点,提出发电厂在建设（包括减载）及运营期间应按设计或相关规范要求,对建筑物及其周围进行沉降监测,以便掌握建筑物的沉降现状和规律,对发电厂的安全运营具有重要的参考价值。     

国内气象服务研究中的公共气象服务主题分析

为了探究国内气象服务研究中公共气象服务主题的研究状况及趋势,对1986~2010年以"气象服务"为主题的1439篇学术论文进行了知识图谱分析,整理出包括公共气象服务在内的14个气象服务研究热点。研究结果表明公共气象服务研究包含于应用气象服务研究层次,处于气象时效性低、服务专业性高的研究领域,与农业气象服务、气象信息服务、气候资源服务、应用气象服务等热点领域存在交叉性的特征,具有面向决策气象服务、公众气象服务、新农村建设、气象服务产业化和气象事业可持续发展的需求,侧重于信息传播、预警、效益、安全、网络的研究趋势。     

青岛潮间带趋磁细菌的垂直分布特征及与环境因子的关系

趋磁细菌是一类能够沿着磁力线运动的革兰氏阴性细菌, 主要生活在淡水和海洋的有氧-无氧过渡区。本调查通过对青岛汇泉湾潮间带沉积物柱状样分层样品中趋磁细菌的计数和沉积物理化因子的分析, 研究了趋磁细菌的垂直分布特征及其与环境因子的关系。结果显示趋磁细菌以趋北型的趋磁球菌占优势, 主要分布环境的氧化还原电位为179.7～-107.0 mV, 为弱还原-还原性质, 最大丰度(94～169个/cm³)出现在氧化还原跃层(表层下5～9cm黄-黑沙界面处), 暗示有氧-无氧过渡区; 趋磁细菌的垂直变化趋势与粒径、含水率、硫酸盐的变化趋势基本一致。