福建省复杂地形下旬平均气温分布式模拟

为建立高时空分辨率的福建省复杂地形下气温栅格数据集,利用福建省及其周边33个常规气象站观测资料,基于数字高程模型（DEM）数据,综合考虑海拔、太阳总辐射、地表长波有效辐射对旬平均气温的影响,模拟了福建省复杂地形下旬均温的空间分布。结果表明：1）常规站验证结果显示：各旬气温绝对误差平均值（MAE）最小为0.46℃,最大为2.3℃,全年平均为0.87℃;加密站验证结果显示,MAE最大为2.3℃,最小0.5℃,全年平均为0.96℃。2）模拟结果能反映旬均温的宏观分布规律与局地细节特征。宏观范围内,旬均温受纬度影响较大,由北至南气温逐渐升高,沿海地区旬均温整体高于内陆,山区旬均温明显较低;局地范围内,各坡向上气温差异显著,海拔越高、坡度越大,差异越明显;地形因子对旬平均温的影响具有季节差异,具体表现为冬季时地形因子对旬均温的影响最大,秋季次之,春夏季节中地形因子对旬均温的影响最弱。     

雅安市雨城区壶穴形态特征

以雅安市雨城区的严桥河和周公河流域的河床壶穴为研究对象,对128处壶穴形态规模与几何参数进行详细测量。运用定量统计方法分析壶穴的分布规模和形态特征。结果表明:周公河流域壶穴大多分布在岸边大石块上,严桥河流域壶穴主要分布于河床的岩坎上;两地壶穴平均分布密度为0.43个/m2,相对其他区域较小,且壶穴的长短轴和平均口径与深度都有相对明显的规律。在平面形态上,壶穴形态多样,周公河以近圆型壶穴最多,占52.5%,严桥河以椭圆型壶穴最多,占63.6%。在垂直剖面形态上,周公河处壶穴90%属于U型,其余为V型;严桥河处壶穴V型和U型分别占52.3%和44.3%,还有3.4%属倒Ω型;两地壶穴都以浅型为主。     

Identification of dissolved and particulate carbonyl compounds produced by marine harmful algal bloom species

Carbonyl compounds, especially polyunsaturated aldehydes (PUAs), are increasingly reported as teratogenic to grazers and deleterious to phytoplankton. While PUAs have been considered to be mainly produced by diatoms after cell wounding, little is known about whether microalgae other than diatoms, particularly harmful algal bloom (HAB)-forming species, produce carbonyl compounds. In this study, we analyzed the carbonyl compounds from eight common HAB-forming species ( Akashiwo sanguinea , Karenia mikimotoi , Karlodinium venefi cum , Margalefi dinium polykrikoides , Prorocentrum donghaiense , P . minimum , Scrippsiella trochoidea , and Heterosigma akashiwo ) using gas chromatography-mass spectrometry in full scan and selected ion monitoring (SIM) modes. Our results show a ubiquitous presence of carbonyl compounds in both dissolved and particulate forms in all species we examined. In the full scan mode, 133 chromatographic peaks were detected from 51 samples altogether. Both the varieties of carbonyl compounds and their quantities were algal species dependent, although most of the carbonyl compounds could not be fully identifi ed according to the mass spectral database only due to the unavailability of enough standards for all analytes. Aided with nine standards in SIM mode, we further identifi ed and quantifi ed all nine aldehydes (2-methyl-2-pentenal, trans-2-nonenal, cis-6-nonenal, 2,6-dimethyl-5-heptenal, trans-2-hexenal, trans-2- decenal, 2,4-heptadienal, trans-trans-2,4-octadienal, and trans-trans-2,4-decadienal). Four of these nine aldehydes were detected in particulate form, which confi rmed that trans-2-nonenal could be produced by K . mikimotoi , Karl . venefi cum , P . donghaiense , P . minimum , S . trochoidea , and H . akashiwo , 2,4-heptadienal and trans-trans-2,4-decadienal by A . sanguinea , M . polykrikoides , and S . trochoidea , and trans, trans-2,4- octadienal by S . trochoidea , respectively. We proved that some dinofl agellate and raphidophyte species could contribute to the pool of carbonyl compounds including PUAs in a marine ecosystem. Some carbonyl compounds, particularly those in high cell quota and/or dissolved concentration, may be related to fi shkilling or allelopathy which needs further identifi cation and quantifi cation.     

水下航行体垂直出筒时水锤压力分析与研究

对航行体离筒后海水倒灌后形成的水锤效应进行了研究。 通过数据分析,描述了发射筒内产生的水锤压力现象,分析了水锤压力产生的机理,采用 CFD 分析方法对海水涌入发射筒后的流场特性和载荷特性进行了数值模拟计算;建立了水锤压力峰值估算模型,计算了航行体离筒速度和离筒时筒内压力的变化对发射筒底部压力的影响,得到不同工况条件下水锤效应的变化规律。     

火星陨石NWA 8716的岩矿学特征及粗粒橄榄石斑晶的来源

火星陨石可以为研究火星岩浆演化过程提供直接证据并限制其源区特征.通常认为含粗粒橄榄石斑晶辉玻无球粒陨石携带有火星原始地幔的信息,因此选取该类样品Northwest Africa (NWA) 8716为研究对象,进行岩相结构及矿物成分分析. NWA8716由橄榄石、辉石、填隙状熔长石以及其他次要矿物组成.其中橄榄石颗粒有两种级别的粒径,长轴分别约为0.5–1.8 mm和50–400μm.较小橄榄石斑晶内部的熔体包裹体和NWA 8716全岩成分(计算值)均显示明显的轻稀土元素亏损([La/Yb]CI值为0.06–0.1),说明NWA 8716源于一个亏损的火星岩浆池.粗粒橄榄石斑晶的来源对衡量该样品是否能够代表原始熔体成分非常重要.对橄榄石晶体的粒径统计分析发现,粗粒橄榄石斑晶应为堆晶.进一步对铁-镁以及稀土元素分配特征的计算表明NWA 8716并非形成于一个封闭系统,但是计算所得原始熔体成分与全岩成分差异不大,因此粗粒橄榄石斑晶应当来源于与母岩浆成分相似的熔体.总的看来, NWA 8716应当来源于亏损型火星幔源区且演化程度较低.     

Flora小行星族自转特性研究

小行星族作为灾变碰撞的残留物,其基础物理性质提供了其母体以及后续演化信息.其中轨道以及自转特性分别反映了Yarkovsky效应以及Yarkovsky-O’Keefe-Radzievskii-Paddack效应(YORP效应)对于小行星族演化的影响.基于小行星光变数据库(Asteroid Lightcurve Database),通过对Flora小行星族自转速率分布进行研究,发现随着直径减小,族成员自转速率倾向于主要集中在3–5 d^-1的范围内.同时,可以注意到Flora小行星族整体表现出更倾向于顺行自转状态的现象,但对于轨道半长轴小于2.2au的成员来说,其顺行自转与逆行自转状态成员数目比接近于近地小行星中顺逆行自转状态源1:3的比例;此外,对于轨道半长轴大于2.2 au且具有顺行自转状态的部分族成员,在轨道半长轴-绝对星等分布中表现出聚集现象,并在聚集区域中有9颗成员展现出类似Slivan状态特征.     

耀变体在射电波段的偏振研究

利用UMRAO数据库22个耀变体源的偏振数据,根据Lazarian&Pogosyan理论模型分析研究了耀变体射电波段的偏振随波长的变化,得出不同类的耀变体偏振随波长变化的原因。结果表明,与Lazarian&Pogosyan理论模型吻合较好。由此得出如下结论:(1)反常去偏振耀变体源中反常法拉第旋光起主导作用,反常去偏振相对较少;(2)热辐射与同步辐射混合作用,高频波段的偏振度小于低频波段的偏振度(反常去偏振);(3)当被观测波段波长小于吸积盘热辐射对应的维恩波长时,高频波段的偏振度大于低频波段的偏振度(常规去偏振)。     

A new method to determine the gravity field of small bodies from line-of-sight acceleration data

We present a new method to derive line-of-sight acceleration observables from spacecraft radio tracking data. The observables can be used to estimate the mass and gravity of a natural satellite as a spacecraft flyby. The corresponding observation model adapts to one-way and two/three-way tracking modes. As a test case for method validation and application, we estimated the mass and degree two gravity field for the Martian moon Phobos using simulated tracking data when the spacecraft Mars Express flew by Phobos on 2013 December 29. We have a few real tracking data during flyby and they will be used to confirm raw data simulation. The main purpose of this paper is to demonstrate the method of line-of-sight acceleration reduction from raw tracking data and the feasibility to estimate mass and gravity of a natural satellite using this type of observable. This novel method is potentially applicable to planet and asteroid gravity field studies combined with Doppler tracking data.     

The symmetry energy and incompressibility constrained by the observations of glitching pulsars

We investigate the masses of glitching pulsars in order to constrain their equation of state(EOS). The observations of glitches(sudden jumps in rotational frequency) may provide information on the interior physics of neutron stars. With the assumption that glitches are triggered by superfluid neutrons, the masses of glitching neutron stars can be estimated using observations of maximum glitches.Together with the observations of thermal emission from glitching pulsars Vela and J1709–4429, the slope of symmetry energy and incompressibility of nuclear matter at saturation density can be constrained.The slope of symmetry energy L should be larger than 67 MeV while the lower limit of incompressibility for symmetric nuclear matter K_0 is 215 MeV. We also obtain a relationship between L and K_0:6.173 MeV + 0.283 K_0≤ L ≤ 7.729 MeV + 0.291 K_0. The restricted EOSs are consistent with the observations of 2-solar-mass neutron stars and gravitational waves from a binary neutron star inspiral.     

无人机倾斜摄影三维模型在城市雨洪风险评估中的应用

研究城市雨洪风险问题,对提高城市洪涝灾害监测、预报的准确性,以及促进城市防洪决策制定具有重要的意义。鉴于高精度的城市三维模型可以提供丰富地理信息,便于准确分析淹没情况,本文针对当前城市洪涝模型对地形数据的高敏感性,且雨洪风险评估研究的准确性受限于地形数据精度的问题,提出利用无人机倾斜摄影测量技术重建高精度实景三维模型,并结合GIS的空间分析功能,以淹没深度为关键指标进行研究区的雨洪风险评估。通过提取不同重现期下研究区的淹没深度信息,进行可视化渲染实现三维淹没分析,可以直观地看到研究区的淹没情况,作为暴雨内涝风险管理依据,同时对城市规划布局有一定的参考价值。