南海北部海域气溶胶光学厚度研究

气溶胶光学厚度是大气校正所需要的重要参数.利用2006年9月7~30日中科院南海海洋研究所公开航次的多波段太阳光度计资料,得到了南海北部海域的气溶胶光学厚度.分析结果表明,南海北部海域气溶胶光学厚度在一天内的变化非常明显,最小值可达0.1(870 nm),最大值为0.9(440 nm),而日平均气溶胶光学厚度在0.2~0.6之间.结合同步观测气象数据,发现从陆地方向吹来的风,当风速达4 m/s,对气溶胶的光学厚度有非常明显的影响,而从大洋方向吹来的风,对气溶胶的光学厚度影响不明显.     

Effect of the Entrainment Flux Ratio on the Relationship between Entrainment Rate and Convective Richardson Number

The parameterization of the dimensionless entrainment rate (w _e /w _*) versus the convective Richardson number (Ri _δθ ) is discussed in the framework of a first-order jump model (FOM). A theoretical estimation for the proportionality coefficient in this parameterization, namely, the total entrainment flux ratio, is derived. This states that the total entrainment flux ratio in FOM can be estimated as the ratio of the entrainment zone thickness to the mixed-layer depth, a relationship that is supported by earlier tank experiments, and suggesting that the total entrainment flux ratio should be treated as a variable. Analyses show that the variability of the total entrainment flux ratio is actually the effect of stratification in the free atmosphere on the entrainment process, which should be taken into account in the parameterization. Further examination of data from tank experiments and large-eddy simulations demonstrate that the different power laws for w _e /w _* versus Ri _δθ can be interpreted as the variability of the total entrainment flux ratio. These results indicate that the dimensionless entrainment rate depends not only on the convective Richardson number but also upon the total entrainment flux ratio.     

Remote sensing of aerosols over the Solar Village, Saudi Arabia

Aerosol optical properties over Solar Village, Saudi Arabia have been studied using ground-based remote sensing observations through the Aerosol Robotic Network (AERONET). Our analysis covered 8 recorded years of aerosol measurements, starting from February 1999 through January 2007. The seasonal mean values of aerosol optical thickness (AOT), the Ångström wavelength exponent α and the surface wind speed (V), exhibit a one year cyclical pattern. Seasonal variations are clearly found in the shape and magnitude of the volume size distribution (VSD) of the coarse size mode due to dust emission. The Spring is characterized by dusty aerosols as the modal value of the exponent α was low ~ 0.25 while that of AOT was high ~ 0.3. The modal value of wind speed was the highest ~ 3.6 m/s in spring. The increase in wind speed is responsible for increasing the concentration of dust particles during Spring. Spring of 2003 has the highest mean values of AOT, V and VSD and the lowest mean value for the exponent α. The seasonal mean values of the exponent α are anticorrelated with those of the wind speed (r = − 0.63). The annual mean values of the exponent α are well correlated (r = 0.77) with those of the difference between the maximum and minimum values of temperature ΔT. They are anticorrelated (r = − 0.74) with the annual mean values of the relative humidity. Large aerosol particles and high relative humidity increase the radiative forcing. This results in reduction of the values of the temperature difference ΔT.     

大陆岩石圈有效弹性厚度与有关地球物理参数的关系--以泉州-黑水地学断面为例

大陆岩石圈有效弹性厚度(Te)是反映岩石圈综合强度的参数,它反映了岩石圈的整体特征。分析岩石圈有效样性厚度与反映深部地质特征的有关地球物理参数之间的关系,对研究控制Te的因素、各因素之间的关系以及探索大陆构造与大陆动力学等具有重要意义。泉州一黑水地学断面Te与地壳厚度、热岩石圈厚度、均衡重力异常、磁性构造层底面深度、上地幔低速层顶界面深度、上地幔低阻层顶面深度之间的关系研究表明：Te与大地热流关系密切的“热”地球物理参数磁性构造层底面深度、热岩石圈厚度相关性好;与地壳厚度有一定的相关性;上地幔低速层顶界面深度和上地幔低阻层顶面深度与大陆岩石圈Te相关性均较差。     

Thickness estimation of the Longbasaba Glacier: methods and application

A total of 71,177 glaciers exist on the Qinghai-Tibet Plateau, according to the Randolph Glacier Inventory (RGI 6.0). Despite their large number, glacier ice thickness data are relatively scarce. This study utilizes digital elevation model data and ground-penetrating radar thickness measurements to estimate the distribution and variation of ice thickness of the Longbasaba Glacier using Glacier bed Topography (GlabTop), a full-width expansion model, and the Huss and Farinotti (HF) model. Results show that the average absolute deviations of GlabTop, the full-width expansion model, and the HF model are 9.8, 15.5, and 10.9 m, respectively, indicating that GlabTop performs the best in simulating glacier thickness distribution. During 1980-2015, the Longbasaba Glacier thinned by an average of 7.9±1.3 m or 0.23±0.04 m/a, and its ice volume shrunk by 0.28±0.04 km³ with an average reduction rate of 0.0081±0.0001 km³/a. In the investigation period, the area and volume of Longbasaba Lake expanded at rates of 0.12±0.01 km²/a and 0.0132±0.0018 km³/a, respectively. This proglacial lake could potentially extend up to 5,000 m from the lake dam.     

海底滑坡作用下滩海管道结构安全分析

海底滑坡作为常见的海洋地质灾害,对海洋油气工程安全产生巨大威胁。海床土体失稳引起滑坡体滑动,会对海底管道产生拖曳作用。基于计算流体动力学方法(CFD)建立海底滑坡体对管道作用的评估模型,采用H-B模型描述块状滑坡体并与试验比较验证,分析不同海床倾斜度滑坡对管道的作用并拟合表达式;研究了海底管道在滑坡作用下的力学响应,并采用极限状态方法开展海底滑坡作用下管道结构极限安全分析,探讨了管道埋地状态时的极限安全界限,建立滑坡作用下管道结构安全分析方法。研究表明:滑坡对管道作用力与海床倾角呈现正相关,而覆土层厚度对作用力影响较小;随着不排水抗剪强度的减小,允许的滑坡宽度和速度均增加,表明土体不排水抗剪强度与引起的拖曳力呈正相关;滑坡土体宽度对极限安全速度影响较大。     

安徽省电线积冰标准冰厚的气象估算模型

基于逐步多元线性回归和人工神经网络两种方法,利用安徽省有电线积冰观测的15个气象台站建站至2008年的观测资料,建立了安徽省3个不同区域电线积冰标准冰厚的气象估算模型。结果表明:相比人工神经网络模型,逐步多元线性回归模型预测效果较好;在覆冰机理认识上,印证了影响标准冰厚主要是气温、湿度和风速3个因子的配置,其中气温是影响覆冰的最重要因子;平原和丘陵地区的标准冰厚受当日气象条件影响更多,而高山地区与前几日及当日的气象条件均密切相关,且26个气象因子 (1987—2008年资料) 构建的模型的预测效果好于24个气象因子长序列 (建站—2008年资料) 效果。最后利用最优模型推算各区域非观冰站电线积冰标准冰厚,为冰冻灾害的评估以及风险区划的开展提供了基础。     

利用MODIS气溶胶产品研究亚洲季风对气溶胶传输及其分布的影响

利用NASA Terra和Aqua卫星MODIS气溶胶卫星产品,统计了亚洲地区气溶胶光学厚度的空间和季节变化特点,发现东亚与南亚两气溶胶光学厚度高值区年际变化类似,季节变化有所不同。同时结合季风区气候条件,分析亚洲季风对气溶胶分布传输的影响,认为南亚气溶胶光学厚度大值区主要是由于南亚季风和高原地形综合作用形成,东亚地区主要是以当地人类活动产生的气溶胶为主,夏季会受到南亚地区气溶胶输送的影响。光学厚度大值区会随着强季风移动。     

Noise characteristics of an electromagnetic sea-ice thickness sounder on a fixed wing aircraft

In this paper, the noise sources of an airborne electromagnetic frequency domain instrument used to measure sea-ice thickness are studied. The antennas are mounted on the wings of an aircraft. The paper presents real data examples showing that strong noise limited the accuracy of the thickness measurement to ± 0.5 m in the best case. Even drift cor­rection and frequency ?ltering did not reduce the noise to a level necessary for sea ice thickness measurements with an accuracy of 0.1 m. We show results of 3D ?nite element modeling of the coupling between transmitter and receiver coils and the aircraft, which indicate that wing ?exure is the primary cause of the strong noise. Wing de?ection angles below 5° relative to the fuselage are large enough to cause changes higher than the wanted signal from the seawater under the ice. Wing ?exure noise can be divided into an inductive and geometric contribution, both of the same order. Most of the wing ?exure signal appears on the inphase component only, hence the quadrature component should be taken for sea ice thickness retrievals when wing ?exure is present even when the inphase produces a larger ocean sig­nal. Results also show that pitch and roll movements of the aircraft and electromagnetic coupling between seawater and aircraft can contribute signi?cantly to the total noise. For ?ight heights of 30 m over the ocean these effects can change the sig­nal by about 10% or more. For highly quantitative measurements like sea-ice thickness all these effects must be taken into account. We conclude that a ?xed wing electromagnetic instrument for the purpose of measure­ments in a centimeter scale must include instrumentation to measure the relative position of the antenna coils with an accuracy of 1/10 mm. Furthermore the antenna separation distance should be as large as possible in order to increase the measured ratio of secondary to primary magnetic field strength.     

陕西铜峪铜矿床主要特点及开发利用中遇到的问题及对策

铜峪铜矿是陕西地矿局第八地质队1972-1979年勘查探明的一个火山岩型的小型铜矿床,探明铜矿石量1047．88万吨,金属量65064．64吨,平均品位0．62％。共圈铜矿体73条,其中主矿体9条,主矿体储量占总储量77％,矿石量803万吨,金属量49778吨,平均品位0．62％。最大的主矿体7号矿体（盲矿体）,矿石量185万吨,金属量13826吨,平均品位0．75％。矿体分布集中,多为扁、鸡窝状,尖灭再现明显,矿体与围岩属渐变过渡关系,没有明显界线,矿体厚度变化较大。开发利用发现矿体厚〈3m时,开采贫化率〉50％,无法开采利用（以往勘查最小可采厚度≥0．8m）。根据这一情况,按照最小可采厚度≥3m,重新对主矿体进行了圈定,开采矿体厚度≥3m的矿体或矿体中厚度≥3m的部分,有效的把矿石的贫化率控制在30～35％之间,实现了矿山规模化生产、保证了矿石入选品位。