Airborne imagery of a disintegrating Sargassum drift line

Airborne hyperspectral and thermal infrared imagery collected over the Florida Current provide a view of the disintegration of a Sargassum drift line in 5 m s⁻¹ winds. The drift line consists mostly of rafts 20-80 m² in size, though aggregations larger than 1000 m² also occur. Rafts tend to be elongated, curved in the upwind direction, and 0.1-0.5 °C warmer than the surrounding ocean surface. Long weed ‘trails’ extending upwind from the rafts are evidence of plants dropping out and being left behind more rapidly drifting rafts. The raft line may be a remnant of an earlier Sargassum frontal band, which is detectible as an upwind thermal front and areas of submerged weed. Issues are identified that require future field measurements.     

Very quiet intervals of geomagnetic activity and the solar wind structure

Extended periods of very low geomagnetic activity as described by very quiet intervals (VQI's) occur only at those times when the solar wind velocityV has a generally decreasing trend, i.e., they mainly occur either after the velocity peak of a high speed solar stream has passed the Earth, or at times when the Earth is immersed in a low speed solar plasma provided that the daily mean value ofdV/dt is negative. The VQI's most frequently start whendV/dt<0 anddB _Z/dt>0 (B _Z is the geocentric solar magnetrospheric-GSMZ-component of the IMF) and end most likely whendV/dt>0 anddB _Z/dt<0. The temporal trends of the solar wind (SW) velocity affect the variation of thea _p index only when the level of geomagnetic activity is generally low.It is suggested that a gradual expansion or contraction of the magnetosphere, associated with a slow variation of the SW pressure, plays a role in the modification of the reconnection-driven magnetohydrodynamic (MHD) fluctuations in the magnetosphere.     

关于发展我国地下流体前兆流动观测问题的建议

从主机故障、传感器故障、避雷系统故障、供电系统故障4个方面,对天津流体台网水温观测系统故障事件及其跟踪分析进行讨论,提出规范化的排查思路及记录处理方法,可供兄弟台站作为同类数据跟踪分析工作的参考。     

Ion winds in Saturn's southern auroral/polar region

We present profiles of the line-of-sight (l.o.s.) ionospheric wind velocities in the southern auroral/polar region of Saturn. Our velocities are derived from the measurement of Doppler shifting of the H₃⁺ν₂Q(1,0⁻) line at 3.953 microns. The data for this study were obtained using the facility high-resolution spectrometer CSHELL on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii, during the night of February 6, 2003 (UT). The l.o.s. velocity profiles finally derived are consistent with an extended region of the upper atmosphere sub-corotating with the planet: the ion velocities in the inertial reference are only 1/3 of those expected for full planetary corotation. We discuss the results in the light of recent proposals for the kronian magnetosphere, and suggest that, in this region, Saturn's ion winds may be under solar wind control.     

非等间隔灰色GM(1,1)模型在沉降数据分析中的应用

本文用灰色系统理论的非等间隔模型GM(1,1)对西安市朱雀大厦周边建筑物及地表沉降观测数据进行了建模、分析和预测,并且与传统的回归模型拟合结果进行了比较,比较的结果验证了该灰色模型在建筑物及地表沉降变形分析中的实用性、正确性和有效性。     

地电阻率井下观测装置抗干扰能力实验研究

开展地电阻率深井观测系统对地面已知干扰源的抗干扰能力测试,对测试结果进行量化研究,分析地表电磁干扰对地电深井观测的影响程度,期望为将来地电深井方法的研究提供帮助.     

A neutron diffraction study of alkali cation migration in montmorillonites

Neutron powder diffraction measurements on lithium and cesium saturated montmorillonite samples before and after heat treatment at 300°C are studied, in order to undertake a complete refinement of crystal structure and unravel the migration mechanism for the interlayer cations of Li or Cs. Rietveld analysis of the corresponding diffraction patterns finds that montmorillonite crystallizes in the C2/m space group with unit cell dimensions consistent with the size of the specific interlayer cation. We show that thermal treatment affects the two types of samples in a different way. This is with respect to their unit cell dimensions and the migration of Li from the 2b to the 2c clay lattice site, in constrast to the Cs positioning which remains effectively unchanged.     

Optical Response of the Atmosphere During the Caribbean Total Solar Eclipses of 26 February 1998 and of 3 February 1916 at Falcón state,Venezuela

An investigation of the optical response of the atmosphere before, during, and afterthe total solar eclipse of 26 February 1998 at the Caribbean Peninsula of Paraguaná (Falcón State) in Venezuela, was made by measuring photometrically the intensity of the sky brightness in three strategic directions: zenith, horizon anti-parallel or opposite the umbra path, and horizon perpendicular to this path. From these measurements, and by applying in an inverse way an empirical photometric model, very rough estimations of theextinction coefficient, and also of the average optical depth, were obtained in one of these particular directions. However based on meteorological measurements such as those of relative humidity and temperature, and applying a different model, a better estimation in the visual of the total global extinction coefficient of the sky (except the horizon), were made considering the contribution of each component: atmospheric aerosol, water vapour, ozone and Rayleigh scattering. It is shown that this global coefficient is mostly dependent upon aerosol extinction. In spite of the strong reduction of sky brightness photometrically observed during the totality, the results show that the sky was not dark. This is confirmed by the results obtained for the total global extinction coefficient. Additionally it is estimated that the total solar eclipse that took place also in Falcón State, Venezuela, at the beginning of the last century on 3 February 1916, was 30% darker that the 1998 eclipse, and that atmospheric aerosol played a relevant and similar role in the scattering of sunlight during the totality as it was for 1998's. Visual observations made during each event, which show that at length only one or two bright stars could be seen in the sky, support the results obtained for both eclipses.     

多台国内外先进天气现象仪对比分析

业务降水现象仪作为一种降水滴谱测量设备,可以用于天气现象判断,其包含的降水滴谱信息更是反映了诸多降水微物理特征,而不同设备的观测特性和精度存在一定的差异,了解不同设备的差异,对其资料的后续应用有重要的意义。本文利用2018年湖北省咸宁市黑山观测站8次液态降水过程中地面降水观测、DSG5型业务降水现象仪与同址的Parsivel型降水滴谱仪测量的降水粒子谱信息及其反演的物理参量,共1 503对样本开展对比分析,研究结果表明：(1)相比于地面自动站降水数据,Parsivel与地面观测一致性较高,DSG5则有一定的偏小。(2)相对于DSG5,Parsivel观测的粒子数浓度N_w相对较多、质量加权平均直径D_m则相对较小。(3)对于分钟雨强RR≥20 mm·h^-1的降水,Parsivel粒子直径小于(大于)3 mm数浓度高于(低于) DSG5的观测。(4)对于直径大于4 mm的粒子,Parsivel的观测的下落速度略低于理论值,DSG5则明显大于理论值。另外,2次雨雪转换过程中降水现象观测对比研究表明DSG5对降水现象有着良好的观测,相比于Parsivel,其在降水相态转换过程中的天气现象与人工观测结果一致性更好。

     

X射线荧光光谱法分析不同类型岩石中10种主量元素的测试能力验证

以28个不同类型岩石标样作外标,用玻璃熔片法制样,采用经验系数法进行基体校正,建立了X射线荧光光谱法(XRF)测定不同类型岩石中硅铝钙镁等10种主量元素的分析方法。该方法被用于参与GeoPT分析测试能力验证,15年来分析了23个不同类型的岩石验证样品。经验证该方法对SiO_2、Al_2O_3、K_2O和CaO具有非常好的分析效果(所有测定结果的|Z|2);对于MgO、MnO、TiO_2和Na_2O四个元素,尽管各有一个样品的分析结果的|Z|2,这主要是样品与标样的基体差异较大造成了低含量样品测定结果超差,但依然可获得好的分析效果;当TFe_2O_31.0%,P_2O_5含量在0.08%~0.80%区间时,分析结果的|Z|2,满足分析期望。总体上所建立的XRF分析方法稳定,可满足应用地球化学实验室测试不同类型岩石中10种主量元素的分析期望。