中国水汽输送年际和年代际变化研究进展

大气中的水汽输送对于全球的水分循环、气候系统、生态环境等具有重要意义。水汽输送是影响中国旱涝空间分布的重要因素，其年际和年代际变化与厄尔尼诺-南方涛动、海温、北大西洋涛动、太平洋年代际涛动等因素对东亚大气环流的调控作用有关。本文就近期关于中国地区水汽输送年际和年代际变化的部分研究工作进行了回顾和评述，包括影响中国东部降水年际和年代际变化的水汽输送机制、影响梅雨特征年代际变化的水汽输送机制、热带海温对中国上空水汽输送的影响机制等问题。此外，本文回顾了近期与青藏高原地区水汽输送机制有关的研究进展。     

Teleconnection between Sea Ice in the Barents Sea in June and the Silk Road,Pacific–Japan and East Asian Rainfall Patterns in August

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes.Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east–west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific–Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.     

A Trend towards a Stable Warm and Windless State of the Surface Weather Conditions in Northern and Northeastern China during 1961–2014

This study investigates the trends in the mean state and the day-to-day variability(DDV) of the surface weather conditions over northern and northeastern China(NNEC) during 1961–2014 using CN05.1 observational data. In this study, we show that the surface temperature(wind speed) has increased(decreased) over NNEC and that the DDV of the surface temperatures and wind speeds has decreased, indicating a trend towards a stable warm and windless state of the surface weather conditions over NNEC. This finding implies a trend towards more persistent hot and windless episodes, which threaten human health and aggravate environmental problems. The trends are also examined in reanalysis data. Both the ERA-40 and the NCEP data show an increasing(decreasing) trend in the mean state of the surface temperatures(wind speeds). However, the reanalysis data show a consistent decreasing trend in the DDV of the surface weather conditions only in the spring. The underlying reason for the decreased DDV of the surface weather conditions is further analyzed, focusing on the spring season. Essentially,the decreased DDV of the surface weather conditions can be attributed to a decrease in synoptic-scale wave activity, which is caused by a decrease in the baroclinic instability. There is a contrasting change in the baroclinic instability over East Asia, showing a decreasing(increasing) trend north(south) of 40°N. This contrasting change in the baroclinic instability is primarily caused by a tropospheric cooling zone over East Asia at approximately 40°N, which influences the meridional temperature gradient over East Asia.     

Driving forces of aeolian desertification in the source region of the Yellow River: 1975–2005

The source region of the Yellow River, located in the northeastern portion of the Qinghai–Tibet Plateau, plays a critical role in water conservation, biodiversity protection, and wetland conservation. Aeolian desertification of this area is an important concern. Remote sensing and GIS technology were employed to assess the trends in aeolian desertification from 1975 to 2005. The monitoring results showed that, aeolian desert land increased from 15,112 to 17,214 km² during 1975–2005. In addition, it was found that the area of aeolian desertification increased rapidly from 1975 to 1990, was stable from 1990 to 2000, and slightly decreased from 2000 to 2005. Increasing temperature, overgrazing, and drainage of wetlands have been key driving factors of aeolian desertification. Thus, to control the expansion of aeolian desert lands in the source region of the Yellow River and to rehabilitate existing desert areas, the priority should be given to altering human behavior in these areas.     

地铁车站基坑信息化施工监测体系的研究

介绍了武汉地铁二号线小龟山车站基坑信息化施工监测体系构建方法:给出了优化的信息反馈流程:根据现场信息反馈的实际情况实现了钢支撑方案的优化和围护桩支撑挡墙方案的优化:达到了提高施工效益、降低安全风险之目的。     

Ubuntu 12.04系统下Bernese 5.0安装与升级详解

Linux相对Windows更稳定、更高效,但Linux系统下Bernese的安装比较复杂,普通用户很难独立实现.以Ubuntu 12.04系统为基础,详细介绍Bernese 5.0的安装与升级过程,希望对Bernese的用户有所帮助.     

Distribution and pollution assessment of trace metals in seawater and sediment in Laizhou Bay

Selected trace metals(Pb, Cd, Cu, Hg) and arsenic in seawater and surface sediments of Laizhou Bay were determined, to evaluate their spatial distribution, pollution risk and potential ecological risk. Concentrations of the elements were 0.56–2.07, 0.14–0.38, 12.70–18.40, 0.014–0.094, and 1.13–2.37 μg/L in the seawater and 8.94–32.2, 0.18–0.67, 4.51–30.5, 0.006–0.058, and 5.75–15.3 mg/kg in sediments for Pb, Cd, Cu, Hg and As, respectively. High concentrations of the trace metals and arsenic in seawater and surface sediments were generally observed near the river estuary. The pollution risk result of the elements showed that Cu was the prominent trace metal pollutant in seawater, followed by Hg, Pb, Cd and As. The metal complex pollution index in seawater was at a medium level. The most important trace metal pollutant in sediments was Cd, followed by As, Cu, Pb, and Hg. Our pollution assessment suggests that trace metal pollution in Laizhou Bay sediments was at a low level. The potential ecological risk was also low in surface sediment.     

台风路径数值预报实时订正技术及其集成应用

以台风路径数值预报的短时效预报偏差和目标时效（指所需订正的时效）的纬度预报为预报因子,采用多元线性回归方法建立了台风路径预报的偏差预估方程,继而对台风路径预报进行实时订正。本文以12 h为短时效,通过对欧洲中期天气预报中心确定性预报模式（ECMWF-IFS）和集合预报模式（ECMWF-EPS）的台风路径预报的应用,得到以下结论:2018年试报结果表明,24 h、36 h、48 h、60 h、72 h、84 h订正后的ECMWF-IFS台风路径预报的平均距离误差分别比订正前减小了7.3 km、9.3 km、8.9 km、6.5 km、6.9 km、2.6 km,总体来说较强台风（指12 h的台风强度实况≥32.7 m s?1）路径预报的订正效果更好。尝试了先对ECMWF-EPS各成员的台风路径预报进行订正,再进行集成预报,并对比了以下5种方式得到的台风路径预报:“订正后的确定性预报”、“所有集合预报成员集合平均”、“优选集合预报成员集合平均”、“所有集合预报成员先订正再集合平均”和“优选集合预报成员先订正再集合平均”,2018年试报结果表明,对于平均距离误差,24 h和36 h“优选集合预报成员先订正再集合平均”最小,48 h和60 h“所有集合预报成员先订正再集合平均”最小,72 h和84 h“优选集合预报成员集合平均”最小,如果在业务中有针对性地进行应用,有望获得一个在各预报时效表现都较优异的台风路径客观综合预报结果。24 h、36 h、48 h、60 h“优选集合预报成员先订正再集合平均”的平均距离误差分别比“所有集合预报成员集合平均”减小了13.3 km、11.7 km、10.0 km、7.6 km,比中央气象台官方预报（对应的时效为12 h、24 h、36 h、48 h）减小了0.7 km、2.0 km、3.9 km、2.4 km。     

松原地区群体建筑结构地震响应及抗震韧性分析

近年来吉林省松原地区破坏性地震频发,十分必要对当地群体建筑结构的抗震韧性进行分析。对吉林省松原地区的群体建筑结构进行地震响应分析以及抗震韧性评估,对比分析城市和乡镇群体建筑结构在地震作用下的地震响应和抗震韧性。根据《建筑抗震韧性评价标准(GBT 38591—2020)》确定群体建筑结构抗震韧性评估流程,通过韧性指数法和韧性等级法对群体建筑结构的抗震韧性进行定量分析,对城乡抗震韧性的评价结果为当地防震减灾提供理论支持。     

多年冻土区斜坡稳定性研究综述

全球变暖、极端天气频发,引发的地质灾害对自然生态环境和人类生产生活造成了很大的影响。尤其对气候变化较为敏感的高温（年平均地温>-1 °C）和高含冰量多年冻土区,气候变暖以及人类活动导致的冻融地质灾害日益频繁。冻土退化条件下,土体结构和物理力学性质发生改变,黏聚力和抗剪强度降低,造成多年冻土区斜坡发生滑坡、崩塌、泥流等灾害。斜坡失稳加剧了多年冻土区脆弱生态环境的恶化,同时对建（构）筑物安全运营产生威胁。与非冻土区相比,多年冻土区斜坡稳定性研究主要针对高含冰量斜坡段,斜坡失稳模式主要以热融滑塌和活动层滑脱为主。热融滑塌由斜坡段地下冰暴露融化引起,而活动层滑脱产生的原因是冻土融化导致土体孔隙水压力过大,形成的超孔隙水压力降低了土体强度,造成斜坡失稳。此外,多年冻土区斜坡失稳模式还包括融冻泥流、崩塌以及蠕变滑坡等。通过综述近期多年冻土区斜坡稳定性研究进展,概括了多年冻土区斜坡失稳的模式、特征、影响因素、失稳机理、分析方法及防治措施等,并对未来多年冻土区斜坡失稳的研究重点提出建议。