Inertial gravity wave parameters for the lower stratosphere from radiosonde data over China

Characterization of gravity wave(GW)parameters for the stratosphere is critical for global atmospheric circulation models.These parameters are mainly determined from measurements.Here,we investigate variation in inertial GW activity with season and latitude in the lower stratosphere(18-25 km)over China,using radiosonde data with a high vertical resolution over a 2-year period.Eight radiosonde stations were selected across China,with a latitudinal range of 22°-49°N.Analyses show that the GW energy in the lower stratosphere over China has obvious seasonal variation and a meridional distribution,similar to other regions of the globe.The GW energy is highest in winter,and lowest in summer;it decreases with increasing latitude.Velocity perturbations with longitude and latitude are almost the same,indicating that GW energy is horizontally isotropic.Typically,85%of the vertical wavelength distribution is concentrated between elevations of 1 and 3 km,with a mean value of 2 km;it is almost constant with latitude.Over 80%of all the horizontal wavelengths occur in the range 100-800 km,with a mean value of 450km;they show a weak decrease with increasing latitude,yielding a difference of about 40 km over the 22°-49°N range.The ratio of horizontal wavelength over vertical wavelength is about 200:1,which implies that inertial GWs in the lower stratosphere propagate along nearly horizontal planes.Ratios of their intrinsic frequency to the Coriolis parameter decrease with increasing latitude;most values are between 1 and 2,with a mean value of 1.5.Study of the propagation directions of GW energy shows that upward fractions account for over 60%at all stations.In contrast,the horizontal propagation direction is significantly anisotropic,and is mainly along prevailing wind directions;this anisotropy weakens with increasing latitude.     

Joint parameter estimation from magnetic resonance and vertical electric soundings using a multi‐objective genetic algorithm

Magnetic resonance sounding (MRS) has increasingly become an important method in hydrogeophysics because it allows for estimations of essential hydraulic properties such as porosity and hydraulic conductivity. A resistivity model is required for magnetic resonance sounding modelling and inversion. Therefore, joint interpretation or inversion is favourable to reduce the ambiguities that arise in separate magnetic resonance sounding and vertical electrical sounding (VES) inversions. A new method is suggested for the joint inversion of magnetic resonance sounding and vertical electrical sounding data. A one‐dimensional blocky model with varying layer thicknesses is used for the subsurface discretization. Instead of conventional derivative‐based inversion schemes that are strongly dependent on initial models, a global multi‐objective optimization scheme (a genetic algorithm [GA] in this case) is preferred to examine a set of possible solutions in a predefined search space. Multi‐objective joint optimization avoids the domination of one objective over the other without applying a weighting scheme. The outcome is a group of non‐dominated optimal solutions referred to as the Pareto‐optimal set. Tests conducted using synthetic data show that the multi‐objective joint optimization approximates the joint model parameters within the experimental error level and illustrates the range of trade‐off solutions, which is useful for understanding the consistency and conflicts between two models and objectives. Overall, the Levenberg‐Marquardt inversion of field data measured during a survey on a North Sea island presents similar solutions. However, the multi‐objective genetic algorithm method presents an efficient method for exploring the search space by producing a set of non‐dominated solutions. Borehole data were used to provide a verification of the inversion outcomes and indicate that the suggested genetic algorithm method is complementary for derivative‐based inversions.     

符号演算系统及相关软件

Ｍａｔｈｅｍ ａｔｉｃａ、 Ｍ ａｔｌａｂ 等软件是国外较流行的一种符号计算系统。本文简要介绍了国外以 Ｍａｔｈｅｍ ａｔｉｃａ 为主的几种符号演算系统,最后结合实例介绍了 Ｍａｔｈｅｍ ａｔｉｃａ 在物探计算技术和解释中的潜在应用。     

中国地球气候系统模式的发展及其模拟和预估

地球气候系统模式是开展多学科、多圈层集成研究的重要平台,其发展是国际地学领域特别是全球变化领域竞争的前沿。中国的地球气候系统模式研发工作始于20世纪80年代,最近10年得到快速发展。研发格局上已经形成中国科学院、有关部委和高校三足鼎立的局面。文中在简要回顾中国地球气候系统模式早期发展历史的基础上,总结了中国参加第6次耦合模式比较计划的9个地球气候系统模式的技术特点,初步评估了中国4个模式对全球和东亚气候模拟的基本性能,分析了其在4种共享社会经济路径情景下对全球降水与温度的预估变化及其与平衡态气候敏感度的联系。最后,结合国际态势,从发展的角度提出未来中国气候模式研发工作需要加强的8个方向。     

MPLS VPN高速区域网络在天津地震监测系统中的应用.

天津市地震局在“十五”及“十一五”期间,利用MPLS VPN技术,建成了全国最快的区域级地震通信网络系统,实现了54个节点的高带宽互联.本文详细阐述了MPLS VPN技术在天津地震监测系统中的建设与应用情况,以期为今后更好的服务于地震行业提供参考.     

Observational estimation of heat budgets on drifting ice and open water over the Arctic Ocean

It is of major scientific interests to determine the parameters of momentum, heat and vapor exchange in the planetary boundary layer in order to study the effects of ocean-ice-atmosphere interactions and their feedback mechanisms on global climate[1]. Lin…     

沪宁高速公路无锡段春季浓雾的实时监测和若干特征

20 0 0年 2月到 4月沪宁高速公路 ,共监测到 7次低能见度 (<2 0 0m)的春雾。本文应用环境气象监测仪AMW自动气象站 ,每分钟实测的有关资料和相应的环流背景场 ,对 7次春雾形成的物理过程作了研究分析。揭示了春雾形成过程中的若干特征和设计了实施临近预报制作的思路、流程。并论述了在高速公路沿线布设AMW自动气象监测仪的基础上作出低能见度的预测是可行和可能的     

The thermodynamic influence of subgrid orography in a global climate model

Assessments of the impacts of climate change typically require information at scales of 10 km or less. Such a resolution in global climate simulations is unlikely for at least two decades. We have developed an alternative to explicit resolution that provides a framework for meeting the needs of climate change impact assessment much sooner. We have applied to a global climate model a physically based subgrid-scale treatment of the influence of orography on temperature, clouds, precipitation, and land surface hydrology. The treatment represents subgrid variations in surface elevation in terms of fractional area distributions of discrete elevation classes. For each class it calculates the height rise/descent of air parcels traveling through the grid cell, and applies the influence of the rise/descent to the temperature and humidity profiles of the elevation class. Cloud, radiative, and surface processes are calculated separately for each elevation class using the same physical parametrizations used by the model without the subgrid orography parametrization. The simulated climate fields for each elevation class can then be distributed in post-processing according to the spatial distribution of surface elevation within each grid cell. Parallel 10-year simulations with and without the subgrid treatment have been performed. The simulated temperature, precipitation and snow water are mapped to 2.5-minute (~5 km) resolution and compared with gridded analyses of station measurements. The simulation with the subgrid scheme produces a much more realistic distribution of snow water and significantly more realistic distributions of temperature and precipitation than the simulation without the subgrid scheme. Moreover, the 250-km grid cell means of most other fields are virtually unchanged by the subgrid scheme. This suggests that the tuning of the climate model without the subgrid scheme is also applicable to the model with the scheme.     

Simplified formulae for designing coastal forest against tsunami run-up: one-dimensional approach

In the present study, laboratory experiments were conducted to validate the applicability of a numerical model based on one-dimensional nonlinear long-wave equations. The model includes drag and inertia resistance of trees to tsunami flow and porosity between trees and a simplified forest in a wave channel. It was confirmed that the water surface elevation and flow velocity by the numerical simulations agree well with the experimental results for various forest conditions of width and tree density. Further, the numerical model was applied to prototype conditions of a coastal forest of Pandanus odoratissimus to investigate the effects of forest conditions (width and tree density) and incident tsunami conditions (period and height) on run-up height and potential tsunami force. The modeling results were represented in curve-fit equations with the aim of providing simplified formulae for designing coastal forest against tsunamis. The run-up height and potential tsunami forces calculated by the curve-fit formulae and the numerical model agreed within ± 10% error.     

SDSS J143030.22-001115.1： A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum

We used multi-component profiles to model the Hβ and [OⅢ]λλ4959,5007 lines of SDSS J143030.22-001115.1, a narrow-line Seyfert 1 galaxy (NLS1) in a sample of 150 NLS1 candidates selected from the Sloan Digital Sky Survey (SDSS), Early Data Release (EDR). After subtracting the Hβ contribution from narrow line regions (NLRs), we found that its full width half maximum (FWHM) of broad Hβ line is nearly 2900km s~(-1) , significantly larger than the customarily adopted criterion of 2000 km s~(-1) . With its weak Fe Ⅱ multiples, we believe that SDSS J143030.22-001115.1 should not be classified as a genuine NLS1. When we calculate the virial black hole masses of NLS1s, we should use the Hβ linewidth after subtracting the NLR component.