大气对流层平流层交换(STE)研究进展

大气平流层对流层交换(Stratosphere-Troposphere Exchange,STE)包括平流层向对流层的输送(Stratosphere-Troposphere Transport,STT)和对流层向平流层的输送(Troposphere-to-Stratosphere Transport,TST)2个过程,通常统称为STE交换过程.其对大气的辐射平衡、化学成分具有重要影响.研究STE对于大气化学、气候变化、平流层对流层耦合模式的发展等领域意义重大.对国内外不同尺度STE的观测、模拟与诊断做了评述,讨论了各种尺度STE的机制,比较了不同诊断方法和模式的性能和特点.着重指出目前天气尺度STE的研究虽然比较充分,但在STE过程中,中小尺度混合、湍流混合等物理过程的机制、诊断以及模拟方法的研究还有待提高.中小尺度强对流引起的TST对对流层污染物向平流层的输送作用和影响越来越受到关注.在全球快速城市化的背景下,研究城市群高污染区域强对流天气引起的TST过程及其影响具有重要的科学意义.     

华南前汛期强降水个例模式降水预报误差成因初探

2015年5月19—20日,华南出现一次暴雨过程。检验表明欧洲中期天气预报中心全球确定性预报模式(以下简称EC模式)预报的20日强降水落区在广东境内较实况明显偏北,高估了天气尺度系统附近的降水强度,漏报了其南侧暖区内中尺度对流系统(mesoscale convective system,MCS)造成的降水,华东中尺度模式预报明显优于EC模式。利用高分辨率中尺度天气研究预报模式(以下简称WRF模式)对该暴雨过程进行了模拟,对比EC模式降水物理过程,初步探索了EC模式降水预报误差的成因,结果表明:20日位于广东暖区内的对流组织发展成MCS,并造成明显的低层冷池出流和中高层潜热加热,二者共同作用使得中低层气旋式环流在广东中东部发展,配合其南侧的强西南风水汽输送,在气旋式切变附近不断触发新的对流并南移使得广东中南部暖区内出现强降水,WRF模式能较好地模拟出该过程,而EC模式未能预报出暖区对流及其反馈,从而导致其漏报了广东中南部的强降水;EC模式预报的降水与天气尺度环流之间的正反馈进一步加大了降水的预报偏差。EC模式预报的20日白天的强降水主要位于华南北部切变线附近,且以层状云降水为主,降水产生的潜热使得对流层低层切变线附近减压更明显,预报的切变线辐合较分析场明显偏强,使得其预报的切变线附近降水较实况偏强。     

The flexible global ocean-atmosphere-land system model, Grid-point Version 2: FGOALS-g2

This study mainly introduces the development of the Flexible Global Ocean-Atmosphere-Land System Model: Grid-point Version 2 (FGOALS-g2) and the preliminary evaluations of its performances based on results from the pre-industrial control run and four members of historical runs according to the fifth phase of the Coupled Model Intercomparison Project (CMIP5) experiment design. The results suggest that many obvious improvements have been achieved by the FGOALS-g2 compared with the previous version,FGOALS-g1, including its climatological mean states, climate variability, and 20th century surface temperature evolution. For example,FGOALS-g2 better simulates the frequency of tropical land precipitation, East Asian Monsoon precipitation and its seasonal cycle, MJO and ENSO, which are closely related to the updated cumulus parameterization scheme, as well as the alleviation of uncertainties in some key parameters in shallow and deep convection schemes, cloud fraction, cloud macro/microphysical processes and the boundary layer scheme in its atmospheric model. The annual cycle of sea surface temperature along the equator in the Pacific is significantly improved in the new version. The sea ice salinity simulation is one of the unique characteristics of FGOALS-g2, although it is somehow inconsistent with empirical observations in the Antarctic.     

华北中部平原地区一次降雪过程雪水比变化特征及成因分析

运用降雪深度加密观测资料,求取2020年2月14日华北中部一次降雪过程的平均雪水比(snow-to-liquid ratio,SLR),并分析了其变化特征和形成原因,发现此次过程SLR在东西方向上变化显著,即自北京平原地区至天津西部逐渐增大,再向东至天津东部又有所减小,京津两地SLR差别大.3h平均的SLR显示北京平原...     

雪峰山地区前震旦纪大地构造演化及沉积岩相特征

本区冷家溪群为奠基于结晶基底之上的陆间裂陷槽沉积的产物,强烈的武陵造山运动,使其基本固结并形成褶皱基底,从而开辟了一个新的构造演化阶段。板溪群及其与之相当地层为板内被动陆缘沉积,无论是沉积性质还是变形变质作用均具有沉积盖层的特征。     

汤西断裂带土壤气体地球化学特征与跨断层短水准变化的关系

为探究卫辉西代村跨断层短水准出现的趋势性变化与断裂活动间的相关性,在跨断层水准观测场地布设1条土壤气Rn和H2浓度测线,复测周期与跨断层水准测量周期基本一致,分别于2018年4月、7月、10月开展3期土壤气Rn和H2浓度测量.同时,为增加观测数据的可靠性,于2018年8月布设了1条与上述3期测线平行的测线并开展土壤气Rn和H2浓度测量.4期土壤气H2浓度测量结果显示,该区土壤气H2浓度背景值处于较低水平,H2浓度异常值所处位置主要集中在距起点150—210 m处,该处为断裂通过处.4期中Rn浓度最大值、背景值和均值的变化幅度均在正常范围内,Rn浓度异常值所处位置也主要集中在距起点150—210 m处,该处可能为断裂通过处.土壤气显示的断裂通过处与该区探槽显示的断裂位置一致.4期土壤气测量结果表明,近期汤西断裂带可能处于相对稳定状态,跨断层水准观测数据的趋势性变化与断裂活动之间相关性不大.     

对流层高层冷涡对“21·7”河南持续性极端暴雨影响分析

2021年7月17—22日河南出现历史罕见持续性特大暴雨,期间我国东部海区上空的对流层高层冷涡(upper tropospheric cold low,UTCL)与河南降水几乎同步增强,对降水天气形势发展存在影响。强降水过程期间河套高空短波槽、黄淮高压脊、UTCL以及日本海阻塞高压形成准静止波列,环流系统异常稳定,由于UTCL在我国东部海区上空停滞,导致西风急流在河南及其以东地区形成大尺度持续性辐散分流。河南暴雨高空辐散区的建立和增强与UTCL西侧的西北风急流增强直接相关;UTCL东侧急流增强了台风烟花的高层流出,有利于台风加强进而影响河南暴雨区水汽输送;UTCL引起的高空下沉运动增强了副热带高压的稳定性,间接增强了从东部海区向河南的偏东风水汽输送。UTCL数值预报不确定性较大,随着预报时效临近,UTCL环流中心不断向偏北方向调整、强度增强,对应河南暴雨落区有向东调整的趋势。集合预报成员中强、弱UTCL环流分组对比表明,较强的UTCL环流有利于增强河南上空的反气旋性辐散流出,对降水增强较为有利,基于集合预报敏感性的诊断进一步证实了上述结论。     

鸡笼山Cu-Au-Mo多金属矿已采中段漏采矿体勘探思路探讨

鸡笼山Cu-Au-Mo多金属矿床是鄂东南矿集区丰山矿田中一个典型的夕卡岩型、斑岩型铜金钼多金属矿,矿体主要赋存于燕山期中酸性侵入岩与大冶组碳酸盐岩建造的接触带及附近,受地层、构造、岩浆岩的联合控制。文章讨论了矿山已采中段中构造错失矿体、边部矿体及盲矿体等漏采矿体的勘探思路、方法及实践,运用成矿规律分析-坑道地质调查-采样分析-重点靶区圈定-坑内钻探验证的工作程序得以实施。     

浙江省嘉兴地区地热地质条件分析与验证

嘉兴地热2号井打出热水,对杭嘉湖平原地热资源勘查及开发具有重要的指导意义。本文对嘉兴地区地热地质条件进行了分析,结合地热2号井综合物探勘查,阐述布孔依据及钻探验证情况。     

Preliminary evaluations of FGOALS-g2 for decadal predictions

The Flexible Global Ocean-Atmosphere-Land System model, Grid-point Version 2 (FGOALS-g2) for decadal predictions, is evaluated preliminarily, based on sets of ensemble 10-year hindcasts that it has produced. The results show that the hindcasts were more accurate in decadal variability of SST and surface air temperature (SAT), particularly in that of Nin o3.4 SST and China regional SAT, than the second sample of the historical runs for 20th-century climate (the control) by the same model. Both the control and the hindcasts represented the global warming well using the same external forcings, but the control overestimated the warming. The hindcasts produced the warming closer to the observations. Performance of FGOALS-g2 in hindcasts benefits from more realistic initial conditions provided by the initialization run and a smaller model bias resulting from the use of a dynamic bias correction scheme newly developed in this study. The initialization consists of a 61-year nudging-based assimilation cycle, which follows on the control run on 01 January 1945 with the incorporation of observation data of upper-ocean temperature and salinity at each integration step in the ocean component model, the LASG IAP Climate System Ocean Model, Version 2 (LICOM2). The dynamic bias correction is implemented at each step of LICOM2 during the hindcasts to reduce the systematic biases existing in upper-ocean temperature and salinity by incorporating multi-year monthly mean increments produced in the assimilation cycle. The effectiveness of the assimilation cycle and the role of the correction scheme were assessed prior to the hindcasts.