Study of the Interaction between Biological Cells of Different Shapes and Sizes and Electromagnetic Fields Produced by Natural Phenomena

We carry out a study of the interaction between electromagnetic fields produced innature and cells with no structure but with different shapes and sizes, considered asapproximations of those observed in the human body. Magnetic fields produced byvarious atmospheric and geomagnetic phenomena are compared with the fieldsgenerated by the cells themselves. Working with frequencies up to 10⁵ Hz, we found that in most cases lightning is the natural phenomena capable of producingfield intensities comparable to those generated by the cells. As a first approximationwe assume that a cell might be affected only if a field of intensity comparable to thecell's field is present. Oscillating fields of less intensity and their harmonics can involveresonant interactions with the cells, however this situation is not considered here. Under the approximation of our study we found that the size and the shape are parameters of paramount importance: lightning represents a natural hazard only for the largest cells, while the quadrangular cells are not affected by any of the natural phenomena considered here.     

Eastern oyster (Crassostrea virginica) δN as a bioindicator of nitrogen sources: Observations and modeling

Stable nitrogen isotopes (δ¹⁵N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue δ¹⁵N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that δ¹⁵N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal δ¹⁵N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations.     

气压对徐州地区三套体应变仪不同影响原因的分析

通过对徐州地区现有的3台体应变仪不同程度受到气压影响的资料进行对比分析,发现其中2个台的体应变资料受气压影响大,分析出现这种情况的主要原因可能是仪器探头与钻孔耦合得不好造成的。为了减少气压对观测资料的干扰,就需要在仪器下井时做好仪器耦合的基础工作,否则仪器产出的数据将会影响观测资料的使用,受气压严重干扰的资料甚至会误导我们对地震前兆异常的分析和判定。     

EO-1Hyperion高光谱数据FLAASH模块大气纠正及评价

由于受到大气的影响,传感器接收到的辐射信息不能真实地反映地表反射光谱信息,因此,从遥感影像中去除大气的影响,即进行大气校正,是高光谱遥感数据处理中极为重要的环节。文章介绍了EO-1hyperion高光谱数据的特点,以及用FLAASH（Fast Line of Sight Atmospheric Analysis of ...     

亚洲—太平洋夏季风系统的基本模态特征分析

亚洲—太平洋季风区各季风子系统间的相互作用对季风区甚至全球的气候变化都有着显著的影响.整个亚洲—太平洋夏季风系统都处于高层辐散、低层辐合的庞大辐散环流中,从高层辐散中心流出的三支气流分别对推动印度夏季风、东亚副热带夏季风和南海夏季风起着重要的作用,很好地表现了亚洲—太平洋夏季风系统的整体性特征.季风区多种气象要素的基本模态在年代际和年际尺度上都表现出较为一致的变化特征:年代际尺度上亚洲—太平洋夏季风系统整体呈现减弱趋势;年际尺度上存在准2年和准4年的两个周期,其中准2年振荡特征表现为若印度西南季风偏强,则印度季风雨带偏强偏北,导致印度大陆中北部地区降水偏多;同时,由于西太平洋副热带高压的北移和偏强的印度西南季风显著向东延伸,10°N~30°N范围内的西北太平洋地区则表现为异常的气旋性环流,而30°N~50°N之间为反气旋性环流异常,对应东亚夏季风偏强,季风雨带能够北推至我国华北地区.也就是说,当亚洲夏季风中某一季风子系统表现为异常偏强时,另一季风子系统在这一年中也将表现为异常偏强,反之亦然.准2年的振荡周期可能是亚洲—太平洋夏季风系统的一种固有振荡,它从年际尺度上反映了亚洲—太平洋夏季风受热带太平洋—印度洋海温的强迫表现出明显的整体一致特征.     

On Monin–Obukhov Similarity In The Stable Atmospheric Boundary Layer

Atmospheric measurements from several field experiments have been combined to develop a better understanding of the turbulence structure of the stable atmospheric boundary layer. Fast response wind velocity and temperature data have been recorded using 3-dimensional sonic anemometers, placed at severalheights (1 m to 4.3 m) above the ground. The measurements wereused to calculate the standard deviations of the three components of the windvelocity, temperature, turbulent kinetic energy (TKE) dissipation andtemperature variance dissipation. These data were normalized and plottedaccording to Monin–Obukhov similarity theory. The non-dimensional turbulencestatistics have been computed, in part, to investigate the generalapplicability of the concept of z-less stratification for stable conditions. From the analysis of a data set covering almost five orders ofmagnitude in the stability parameter = z/L (from near-neutral tovery stable atmospheric stability), it was found that this concept does nothold in general. It was only for the non-dimensional standard deviation oftemperature and the average dissipation rate of turbulent kinetic energythat z-less behaviour has been found. The other variables studied here(non-dimensional standard deviations of u, v, and w velocity components and dissipation of temperature variance) did not follow the concept of z-less stratification for the very stable atmospheric boundary layer. An imbalance between production and dissipation of TKE was found for the near-neutral limit approached from the stable regime, which matches with previous results for near-neutral stability approached from the unstable regime.     

陕西夏季旱涝的主要环流特征

利用1961—2008年NCEP／NCAR再分析资料以及陕西地面月降水资料,采用EOF分解、合成分析等方法,分析了陕西夏季旱涝的时空分布特征以及前期气候系统的异常信号特征。结果表明：陕西夏季多雨年乌拉尔山高压脊和鄂霍次克海高压偏强,贝加尔湖低槽偏深,西太平洋副热带高压偏强,西伸脊点偏西。并且前期冬季中高纬度中亚长波脊偏强偏西,西太平洋副热带高压偏强,印缅槽偏弱,700hPa西北地区东部至华北偏北风异常偏强,赤道东太平洋出现暖水位相,西风漂流区海温偏低,印度洋海温偏高,陕西夏季易多雨;而陕西夏季少雨年西太平洋副热带高压偏弱,西伸脊点偏东,陕西主要受中亚高脊前西北气流控制。前期冬季中高纬度欧洲西北部低槽偏强,中亚长波脊偏弱,西太平洋副热带高压偏弱,印缅槽偏强,700hPa西北地区东部至华北偏南风异常偏强,赤道东太平洋出现冷水位相,西风漂流区海温偏高,印度洋海温偏低,陕西夏季易少雨。     

基于AERONET数据的气溶胶光学特性分析

大气气溶胶的监测对全球气候变化、区域空气质量和公共健康等研究具有重要的意义,而中国台湾岛四面环海,地理位置特殊,若忽略其大气环流和局地排放源造成的气溶胶特征时空异质性将会导致气溶胶参数反演误差。因此本研究使用中国台湾岛多个具有代表性的AERONET（AErosol RObotic NETwork）观测站历史数据和MODIS气溶胶光学厚度AOD（Aerosol Optical Depth）反演产品,分析5个典型站点气溶胶参数及其类型的时空变化特征及差异,分析结果表明：（1）各站点AOD年平均值逐年下降,呈现春季最高（0.5257）的季节变化特征和双峰结构的日变化规律,主导气溶胶类型为城市工业型（仅鹿林站点为海洋型）。（2）中国台湾地区风向多为东北风,风速越大,AOD值越低,海洋型气溶胶占比越高;反之则以城市工业型气溶胶为主。（3）?ngstr?m波长指数（AE）、单次散射比（SSA）、复折射指数虚部、不对称因子平均值分别为1.3283、0.9564、0.0054、0.7292;相比于北京（39.9768°N,116.3813°E）站,台湾“中央大学”AOD年平均值、季节变化、主导气溶胶类型均存在较大的差异。（4）MODIS AOD分站点验证精度较高,而在高山鹿林站的验证精度稍低（R²=0.5925）;而利用不同气溶胶类型的分类验证结果显示,城市工业（R²=0.7238）、生物质燃烧（R²=0.6161）和次大陆型（R²=0.5116）精度较高,但海洋型（R²=0.1585）、大陆型（R²=0.1111）AOD验证精度显著降低。本研究表明,中国台湾岛气溶胶类型呈现西南沿岸站点秋冬季次大陆型占比上升,西北沿岸大陆型上升的时空特征差异,细化气溶胶参数的时间差异和时间动态变化信息将对气溶胶卫星反演算法在环流特征明显的近海区域有着重要指导作用。     

2017年6月大气环流和天气分析

2017年6月大气环流的主要特征是极涡偏强且呈单极型分布,中高纬环流呈多波型,西太平洋副热带高压强度较常年偏弱。6月全国平均气温20.3℃,较常年同期偏高0.3℃;全国平均降水量112.3 mm,比常年同期(99.3 mm)偏多13%,长江流域入梅时间较常年偏早。我国南方地区有6次区域性暴雨过程,部分地区暴雨洪涝重;与此同时,东北、华北等地少雨高温,干旱持续时间较长;月内今年第2号台风苗柏在广东深圳登陆;全国19个省（区、市）遭受风雹灾害。     

Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations. Part I: Surface fluxes

A mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km² domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm⁻² over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer to the atmosphere is highly non-local and enhanced in the coupled simulation.