46 a气候变化对呼伦湖区域生态环境的影响

 利用1959—2005年温度、降水和卫星遥感监测资料,研究呼伦湖区域气候变化特征,进而分析气候变化对其周边地区生态环境的影响。结果表明：①近46 a来呼伦湖区域温度呈显著的升高态势;降水量波动性较大,总体上呈下降趋势,并存在11 a和22 a的周期性变化。从1999年至2005年降水量下降趋势加快。②无论是温度还是降水,其气候变率都处于升高的时期,气候变率的增大是导致极端气候事件如干旱、高温酷热天气等增多的主要原因。近年来气候的变干、变暖,使得1999年以后呼伦湖区域生态呈现快速恶化的趋势。由此引起一系列生态环境问题,如呼伦湖水域面积的缩小、湿地萎缩、草场退化等。③近年来小雨事件呈减少趋势,但进入21世纪后小雨强度和干燥事件显著增强,致使干旱事件频发和强度的增加,进一步加剧了呼伦湖区域生态环境的恶化。     

Linear mechanism of generation and intencification of internal gravity waves in the ionosphere at their interaction with a nonuniform zonal wind: 1. Model of the medium and initial dynamic equations

The specific features of the generation and intensification of internal gravity wave structures in different atmospheric-ionospheric regions, caused by zonal local nonuniform winds (shear flows), are studied. The model of the medium has been explained and an initial closed system of equations has been obtained in order to study the linear and nonlinear dynamics of internal gravity waves (IGWs) when they interact with the geomagnetic field in a dissipative ionosphere (for the D, E, and F regions).     

一种带误差校正的横波速度预测方法

本文提出一种基于纵横波速度关系的带误差校正的横波速度预测方法,它主要针对在进行横波速度预测时所采用纵波模量M近似变换结果与标准的Gassmann关系(K变换)之间存在的误差提出了校正的方法,并给出了完整的基于纵横波速度关系的带误差校正横波预测技术流程,该技术是一个简单实用的横波速度预测工具.     

A numerical model of the partitioning of trace chemical solutes during drop freezing

Partitioning of volatile chemicals among the gas, liquid, and solid phases during freezing of liquid water in clouds can impact trace chemical distributions in the troposphere and in precipitation. We describe here a numerical model of this partitioning during the freezing of a supercooled liquid drop. Our model includes the time-dependent calculation of the coupled processes of crystallization kinetics, heat transport, and solute mass transport, for a freezing hydrometeor particle. We demonstrate the model for tracer partitioning during the freezing of a 1000 μm radius drop on a 100 μm ice substrate, under a few ambient condition scenarios. The model effectively simulates particle freezing and solute transport, yielding results that are qualitatively and quantitatively consistent with previous experimental and theoretical work. Results suggest that the ice shell formation time is governed by heat loss to air and not by dendrite propagation, and that the location of ice nucleation is not important to freezing times or the effective partitioning of chemical solutes. Even for the case of nucleation at the center of the drop, we found that dendrites propagated rapidly to form surface ice. Freezing then proceeded from the outside in. Results also indicate that the solid-liquid interfacial surface area is not important to freezing times or the effective partitioning of chemical solutes, and that the rate aspects of trapping are more important than equilibrium solid-liquid partitioning to the effective partitioning resulting from freezing.     

The tectono‐stratigraphic evolution of the Austral Basin and adjacent areas against the background of Andean tectonics,southern Argentina,South America

The Austral Basin (or Magallanes Basin) in southern Argentina is situated in a highly active tectonic zone. The openings of the South Atlantic and the Drake Passage to the east and south, active subduction in the west, and the related rise of the Andes have massively influenced the evolution of this area. To better understand the impacts of these tectonic events on basin formation to its present‐day structure we analysed 2D seismic reflection data covering about 95 000 km² on‐ and 115 000 km² offshore (Austral ‘Marina’ and Malvinas Basin). A total of 10 seismic horizons, representing nine syn‐ and post‐ rift sequences, were mapped and tied to well data to analyse the evolution of sedimentary supply and depocenter migration through time. 1D well backstripping across the study area confirms three main tectonic stages, containing (i) the break‐up phase forming basement graben systems and the evolution of the Late Jurassic – Early Cretaceous ancient backarc Austral/Rocas Verdes Basin (RVB), (ii) the inversion of the backarc marginal basin and the development of the foreland Austral Basin and (iii) the recent foreland Austral Basin. Synrift sedimentation did not exceed the creation of accommodation space, leading to a deepening of the basin. During the Early Cretaceous a first impulse of compression due to Andes uplift caused rise also of parts of the basin. Controlling factors for the subsequent tectonic development are subduction, balanced phases of sedimentation, accumulation and erosion as well as enhanced sediment supply from the rising Andes. Further phases of rock uplift might be triggered by cancelling deflection of the plate and slab window subduction, coupled with volcanic activity. Calculations of sediment accumulation rates reflect the different regional tectonic stages, and also show that the Malvinas Basin acted as a sediment catchment after the filling of the Austral Basin since the Late Miocene. However, although the Austral and Malvinas Basin are neighbouring basin systems that are sedimentary coupled in younger times, their earlier sedimentary and tectonic development was decoupled by the Rio Chico basement high. Thereby, the Austral Basin was affected by tectonic impacts of the Andes orogenesis, while the Malvinas Basin was rather affected by the opening of the South Atlantic.     

GPS/GLONASS组合测量误差简介

GLONASS与GPS导航定位技术原理相似，GPS／GLONASS组合测量由于可见卫星数目的增加，可以提高测量的精度、可靠性、完备性。着重介绍了GPS／GLONASS组合测量中的主要误差源及其性质并给出相应的影响量级。     

地基SAR在滑坡形变监测中的应用

地基InSAR是近年发展起来的基于地基SAR(GB-SAR)获取地表形变的一种新的技术手段,分辨率高、可实时监测,实现毫米级形变监测精度,为近距离滑坡实时监测与预警提供了先进的技术手段。本文首先以澜沧江某滑坡体为研究对象,在滑坡体对岸设立固定站点,按固定频率进行GB-SAR数据采集;然后通过先后两景影像形成干涉对,利用相干阈值方法提取相干点目标;最后利用形变模型提取滑坡体形变结果。研究表明,地基SAR可获得整个滑体形变边界、形变大小空间分布及时间变化历程,对滑坡体灾害实时监测非常有效,可为滑坡灾害监测及预警提供参考。     

道路交通气象服务系统的设计与应用

通过建立更快速的道路交通气象预警发布系统,开展基于位置的道路交通气象服务,将灾害天气情况直接发送给行驶中货车运输的司机,从而尽可能减少因恶劣天气带来的交通事故,保障人民群众生命财产安全。利用中国区域5 km分辨率智能网格天气实况数据和12379全国灾害预警发布平台实时获取全国3 240个县市灾害预警信息,通过建立电子围栏,实时发布所在区域的预报预警信息和行车指数给驾驶员。该系统可实时获取并自动实时发布道路交通任意位置的预警信息、行车指数和天气实况,以短信提醒和语音播报的方式直接为驾驶员提供精细的气象服务。