不同精制方法对鱿鱼（Ommastrephes bartrami）墨黑色素的微观形态、光谱特征及金属元素的影响

采用扫描电镜、光谱分析和元素分析法,进行了胃蛋白酶水解法、高速离心法和酸水解法精制的鱿鱼墨黑色素颗粒形态、紫外可见光谱、红外光谱及金属元素含量的研究。结果表明,酸水解法破坏了鱿鱼墨黑色素的颗粒结构;三种不同精制方法所得的鱿鱼墨黑色素在220nm附近均有强吸收。胃蛋白酶水解和酸水解法有效切除黑色素的氨基基团,但酸水解法下...     

NEOCAM: The Near Earth Object Chemical Analysis Mission

The prime measurement objective of the Near Earth Object Chemical Analysis Mission (NEOCAM) is to obtain the ultraviolet spectra of meteors entering the terrestrial atmosphere from ∼125 to 300 nm in meteor showers. All of the spectra will be collected using a slitless ultraviolet spectrometer in Earth orbit. Analysis of these spectra will reveal the degree of chemical diversity in the meteors, as observed in a single meteor shower. Such meteors are traceable to a specific parent body and we know exactly when the meteoroids in a particular shower were released from that parent body (Asher, in: Arlt (ed.) Proc. International Meteor Conference, 2000; Lyytinen and van Flandern, Earth Moon Planets 82–83:149–166, 2000). By observing multiple apparitions of meteor showers we can therefore obtain quasi-stratigraphic information on an individual comet or asteroid. We might also be able to measure systematic effects of chemical weathering in meteoroids from specific parent bodies by looking for correlations in the depletions of the more volatile elements as a function of space exposure (Borovička et al., Icarus 174:15–30, 2005). By observing the relation between meteor entry characteristics (such as the rate of deceleration or breakup) and chemistry we can determine if our meteorite collection is deficient in the most volatile-rich samples. Finally, we can obtain a direct measurement of metal deposition into the terrestrial stratosphere that may act to catalyze atmospheric chemical reactions.     

Spectra of CO<Subscript>2</Subscript> and Water Vapour in the Marine Atmospheric Surface Layer

Spectra of CO₂ and water vapour fluctuations from measurements made in the marine atmospheric surface layer have been analyzed. A normalization of spectra based on Monin–Obukhov similarity theory, originally developed for wind speed and temperature, has been successfully extended also to CO₂ and humidity spectra. The normalized CO₂ spectra were observed to have somewhat larger contributions from low frequencies compared to humidity spectra during unstable stratification. However, overall, the CO₂ and humidity spectra showed good agreement as did the cospectra of vertical velocity with water vapour and CO₂ respectively. During stable stratification the spectra and cospectra displayed a well-defined spectral gap separating the mesoscale and small-scale turbulent fluctuations. Two-dimensional turbulence was suggested as a possible source for the mesoscale fluctuations, which in combination with wave activity in the vertical wind is likely to explain the increase in the cospectral energy for the corresponding frequency range. Prior to the analysis the turbulence time series of the density measurements were converted to time series of mixing ratios relative to dry air. Some differences were observed when the spectra based on the original density measurements were compared to the spectra based on the mixing ratio time series. It is thus recommended to always convert the density time series to mixing ratio before performing spectral analysis.     

Attached Eddies and Production Spectra in the Atmospheric Logarithmic Layer

We investigate the production components of turbulent spectra within logarithmic layers over flat ground. This assumes that the turbulence giving rise to these spectra consists of active coherent structures (eddies) that are attached to the ground, and whose properties display perfect statistical self-similarity under inner scaling. That is, we take the extreme view that active coherent structures not only contribute to turbulence production spectra but explain the whole of them, so that neither detached eddies nor unstructured motions make any significant contribution. Perfect self-similarityis held to apply only to eddies that are themselves formed totally within the log layer, so the theory applies in the limit of spectra obtained at the hearts of very deep log layers. The model predicts that spectral variance and covariance should become independent of wavenumber at small wavenumbers. This asymptotic behaviour is observed in all neutral spectra from the Kansas experiment. The model also interprets the various positions of the spectral peaks observed at Kansas and in aircraft flights over the sea as consequences of the eddies being aggregated into files aligned with the wind. The observed spectra are therefore consistent with large-scale wedge-like structures being the principal component of active turbulence in the neutral atmospheric surface layer.     

M-LDARS观测的北京地区云地闪特征分析

1991年夏,我们利用自制的单站闪电探测及定位系统(M—LDARS),在北京地区进行了对比实验,并对所记录的地闪回击信号作了分析。本文提出了我们得到的北京地区云地闪回击信号的峰值时间、半峰时间、峰值电流以及电流上升率的统计分布和频谱特征的典型结果,并与国内外同类观测的结果进行了对比。     

Turbulence Characteristics Of The Stable Boundary Layer Over A Mid-Latitude Glacier. Part Ii: Pure Katabatic Forcing Conditions

Observations obtained over a glacier surface in a predominantlykatabatic flow and with a distinctwind maximum below 13-m height are presented. The data werecollected using a 13-m high profilemast and two sonic anemometers (at about 2.5-m and 10-m heights).The spectra at frequencies belowthat of the turbulence range appear to deviate considerably fromthe curves obtained by Kaimal andco-workers during the 1968 Kansas experiment. The characteristicsof these deviations are compared tothe observations of others in surface-layers disturbed by anykind of large-scale outer-layer (orinactive) turbulence. In our case the disturbances arelikely to be induced by the highmountain ridges that surround the glacier. Moreover, the deviationsobserved in the cospectra seemto result from an, as yet, unspecified interaction between theinactive outer-layer turbulenceand the local surface-layer turbulence. Near the distinctwind maximum turbulence production ceasedwhile turbulence itself did not, probably the result ofturbulence transport from other levels. Consequently, we studied thelocal similarity relations using _w instead of u_* as an alternative velocity scale. Wellbelow the wind maximum, and for relatively low stability(0< Ri_g <0.2), the flow behaves accordingto well established local-scaling similarity relationshipsin the stable boundary layer. For higherstability (Ri_g > 0.2), and near or above the wind maximum, the boundary-layer structure conforms tothat of z-less stratification suggesting that the eddy sizeis restricted by the local stability ofthe flow. In line with this we observed that the sensibleheat fluxes relate remarkably well to thelocal flow parameters.     

调制Stokes波列长期演化过程中的熵值分析

深水Stokes波列的不稳定调制演化与实际海面的瞬变性、波浪破碎、畸形波等海洋现象密切相关,且波列在长期演化的过程中,演化特性会随着时间尺度的增加而改变,前人的研究多是针对其空间分布特性,对于波列内部能量的分布和变化趋势尚不清楚,因此引入熵的概念用于描述调制Stokes波列长期演化过程中任意时刻波浪场中不同频率波浪能量分布的均匀性。通过高阶谱方法数值模型,模拟了不同初始波陡条件下调制Stokes波列波数谱熵值的长期演化,给出不同阶段初始波陡和熵的关系,并将稳定状态熵值及谱形与典型海浪谱进行对比分析,发现调制Stokes波列长期演化的波数谱熵值和谱形均趋向实测JONSWAP谱,表明其经过长期演化发展,谱变宽变连续,波场内的能量分布趋向均匀并保持动态的平衡,同时也更加趋近于真实海浪。     

福建省海岸带泥沙分布的气象卫星遥感监测

根据水体对太阳辐射光谱的反射率变化特性,利用NOAA极轨气象卫星遥感资料,动态监测福建省海岸带悬浮泥沙的分布,并从十几幅质量较好的不同时相的泥沙分布图中得出初步的监测结果。     

欧亚大陆山地垂直带数字集成系统的设计与应用

在欧亚大陆山地垂直带880个带谱点数据采集的基础上,设计和开发了山地垂直带数字集成系统。其功能：(1)垂直带谱可视化显示功能：实时生成垂直带地理分布图、垂直带堆积柱状图、上下限高度随经纬度变化曲线;(2)垂直带上下限提取和绝对高度和相对高度转化功能：提取山地垂直自然带分布上限和下限高度,进行垂直带的宽度和垂直带上限海拔...     

基于紫外-可见光吸收光谱和三维荧光光谱的腐殖酸光降解组分特征分析

湖泊生态系统作为自然界重要的碳库,光照强度的变化对于湖泊的碳循环过程可能产生重要的影响.以云南老君山高山湖泊天才湖周边土壤中的腐殖酸作为外源溶解性有机物（DOM）的代表物,通过腐殖酸模拟光降解实验,考察光照强度对外源DOM光降解过程的影响.研究结果表明：腐殖酸光吸收系数a₄₄₀、465 nm和665 nm波长处吸光度比值E₄/E₆的下降幅度均为：对照组 < 20 W光照组 < 40 W光照组,a₄₄₀、E₄/E₆和光谱斜率S_R显著相关,表明紫外辐射使得腐殖酸溶液浓度降低、相对分子量下降,且光照强度越强,腐殖酸的光降解程度越大.通过EEM-PARAFAC模型识别出光降解过程中腐殖酸溶液中含有5种荧光组分：UV类腐殖质（C1）、UVA类腐殖质（C2）、类色氨酸（C3）、UVC类腐殖质（C4）和类络氨酸（C5）.40 W光照组中4种荧光组分的降解程度与降解速率均大于20 W光照组,降解程度均为：C4 > C3 > C2 > C1,降解速率为C2 > C4 > C3 > C1,说明不同的荧光组分对光照强度的响应不同.该研究有助于阐明外源DOM的光降解途径与归趋.