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Impact of oceans on climate change in drylands

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Science China Earth Sciences 2019年第6期62卷 891-908页

作者： xiaodan guan Jieru MA Jianping HUANG Ruixin HUANG Lei ZHANG Zhuguo MA Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University Woods Hole Oceanographic Institution State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences

Drylands account for approximately 41% of the global total land area. Significant warming and rare precipitation in drylands result in a fragile ecology and deterioration of the living environment, making it more sensitive to global climate change. As an important regulator of the Earth's climate system, the oceans play a vital role in the process of climate change in drylands. In modern climate change in particular, the impact of marine activities on climate change in drylands cannot be neglected. This paper reviews the characteristics of climate change in drylands over the past 100 years, and summarizes the researches conducted on the impact of marine activities on these changes. The review focuses on the impact of the Pacific Decadal Oscillation(PDO), Atlantic Multidecadal Oscillation(AMO), El Ni?o and La Ni?a on climate change in drylands, and introduces the mechanisms by which different oceanic oscillation factors synergistically affect climate change in *** have shown that global drylands have experienced a significant intensification in warming in the past 100 years, which shows obvious characteristics of interdecadal dry/wet variations. The characteristics of these changes are closely related to the oscillatory factors of the oceanic interdecadal scale. Different phase combinations of oceanic oscillation factors significantly change the land-sea thermal contrast, which in turn affects the westerly jet, planetary wave and blocking frequency, resulting in changes in the temperature and dry/wet characteristics of drylands. With the intensification of climate change in drylands, the impact of marine activities on these regions will reveal new characteristics in the future, which will increase the uncertainty of future climate change in drylands and intensify the impact of these drylands on global climate.

关键词： Impact of oceans on climate change in drylands AMO

Changes in snow parameterization over typical vegetation in the Northern Hemisphere

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Atmospheric and Oceanic Science Letters 2023年第2期16卷 42-48页

作者： xiaodan guan Xinrui Zeng Rui Shi Han Chen Zhimin Wei Collaborative Innovation Center for Western Ecological Safety College of Atmospheric SciencesLanzhou UniversityLanzhouChina Kunming Xishan District Development and Reform Bureau KunmingChina

季节性降雪对气候变化很敏感,常被当作气候变化的信号.由于其局地特征差异显著,不同下垫面类型的积雪过程也不尽相同.北半球中高纬度的典型下垫面(开阔灌丛,常绿针叶林和混交林)在积雪覆盖率和雪深之间有着独特的关系曲线,这种关系不仅... 详细信息

季节性降雪对气候变化很敏感,常被当作气候变化的信号.由于其局地特征差异显著,不同下垫面类型的积雪过程也不尽相同.北半球中高纬度的典型下垫面(开阔灌丛,常绿针叶林和混交林)在积雪覆盖率和雪深之间有着独特的关系曲线,这种关系不仅代表了积雪过程和融雪过程的特征变化,更能用于模式进行积雪预测.研究发现,北半球中高纬度的增温改变了积雪参数化关系,进一步影响了局地能量和水循环,造成开阔灌丛的北缩和常绿针叶林及混交林的扩张.然而,目前模式中的积雪参数化并不能很好地再现全球变暖影响下融雪阶段出现的加速融化过程,并且进一步影响对春季融雪的生态影响的理解.

关键词：积雪覆盖率雪深开阔灌丛常绿针叶林混交林

Changes in Aridity in Response to the Global Warming Hiatus

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Journal of Meteorological Research 2017年第1期31卷 117-125页

作者： xiaodan guan Jianping HUANG Ruixia GUO Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University Lanzhou 730000

The global warming slowdown or warming hiatus, began around the year 2000 and has persisted for nearly 15 years. Most studies have focused on the interpretation of the hiatus in temperature. In this study, changes in a global aridity index （AI） were analyzed by using a newly developed dynamical adjustment method that can successfully identify and separate dynamically induced and radiatively forced aridity changes in the raw data. The AI and Palmer Drought Severity Index produced a wetting zone over the mid-to-high latitudes of the Northern Hemisphere in recent decades. The dynamical adjustment analysis suggested that this wetting zone occurred in response to the global warming hiatus. The dynamically induced AI （DAI） played a major role in the AI changes during the hiatus period, and its relationships with the North Atlantic Oscillation （NAO）, Pacific Decadal Oscillation （PDO）, and Atlantic Multi-decadal Oscillation （AMO） also indicated that different phases of the NAO, PDO, and AMO contributed to dif- ferent performances of the DAI over the Northern Hemisphere. Although the aridity wetting over the mid-to-high lat- itudes may relieve long-term drying in certain regions, the hiatus is temporary, and so is the relief. Accelerated glob- al warming will return when the NAO, PDO, and AMO revert to their opposite phases in the future, and the wetting zone is likely to disappear.

关键词： hiatus aridity index dynamically induced aridity index wetting

Effect of seasonal snow on the start of growing season of typical vegetation in Northern Hemisphere

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Geography and Sustainability 2022年第3期3卷 268-276页

作者： xiaodan guan Shuyang Guo Jianping Huang Xiaohan Shen Li Fu Guolong Zhang Collaborative Innovation Center for Western Ecological Safety College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

Under global warming, seasonal snow takes faster melting rate than before, which greatly changes the hydro-logical cycle. In this study, by targeting three typical seasonal snow-covered land types (i.e., open shrubland,evergreen needleleaf forest and mixed forest) in the Northern Hemisphere, the start of growing season (SGS) hasbeen found obviously advanced in the past years, greatly contributed by the faster melting rate of seasonal *** is manifested that significantly positive correlation has been found between SGS and May snow depth for openshrubs, March and April snow depth for evergreen needleleaf forests and March snow depth for mixed ***, such close association is not appeared in all the climate conditions of same vegetation. In the future,as the rate of melting snow becomes faster in the high emission of greenhouse gasses than the current situation,continuously advanced SGS will accelerate the change of vegetation distribution in the Northern *** findings offer insights into understanding the effect from seasonal snow on vegetation and promote thesustainable utilization of regional vegetation in the Northern Hemisphere.

关键词： Vegetation distribution Start of growing season(SGS) Snow depth Climate condition Northern hemisphere(NH)

The global response of temperature to high-latitude vegetation greening in a two-dimensional energy balance model

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Atmospheric and Oceanic Science Letters 2020年第1期13卷 80-87页

作者： BI Lu HE Yongli HUANG Jianping LI Yaokun guan xiaodan LIU Xiaoyue Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhouChina College of Global Change and Earth System Science Beijing Normal UniversityBeijingChina

The relationship between vegetation greening and climate change remains unclear due to its complexity, especially in drylands. Against the background of global warming, arid and semi-arid areas, including mid-latitude deserts, are most sensitive to climate change. In recent decades, the mechanisms underlying the relationship between vegetation greening and climate change have been widely discussed in the literature. However, the influence of vegetation greening in high latitudes on regional climate has not been fully studied. In this paper, a two-dimensional energy balance model was used to study the influence of greening in high latitudes on mid-latitude deserts. The authors found that when greening occurs in high latitudes, the mid-latitude desert recedes at the south boundary, while the polar ice belt and low-latitude vegetation belt both expand. Simultaneously, greening in high latitudes can induce a negative temperature anomaly in northern latitudes and a positive temperature anomaly in southern latitudes. The mid-latitude desert expands at its north and south boundaries until the CO2 concentration reaches 600 ppm(saturated state). The greening in high latitudes could result in a lower global-mean temperature in the ‘saturated’ state, due to the stronger cooling in high latitudes.

关键词： High-latitude greening two-dimensional energy balance model mid-latitude desert remote effect global warming

基于雷达—雨量计降水融合方法提高极端降水监测能力

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大气科学 2022年第6期46卷 1523-1542页

作者：李梦迪戚友存张哲管晓丹兰州大学大气科学学院兰州730000 中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室北京100101 中国科学院大学北京100049 深圳市国家气候观象台深圳518040

高时空分辨率、高精度的降水产品对于极端降水的监测以及防灾减灾具有重要意义。地面雨量计提供点尺度降水精确观测,但无法精细化捕捉对流性强降水的空间分布。雷达观测可以精细地刻画降水的空间分布特征,但雷达定量估计降水(QPE,quanti... 详细信息

高时空分辨率、高精度的降水产品对于极端降水的监测以及防灾减灾具有重要意义。地面雨量计提供点尺度降水精确观测,但无法精细化捕捉对流性强降水的空间分布。雷达观测可以精细地刻画降水的空间分布特征,但雷达定量估计降水(QPE,quantitative precipitation estimation)产品估测精度易受雷达观测偏差和Z–R(雷达反射率—降水率)关系等因素影响。因此,本文开展高时空分辨率的雷达—雨量计降水融合算法研究,集成雨量计观测和雷达定量估计降水产品各自的优点。该算法主要步骤包括:雨量站观测数据格点化、局地雨量计订正雷达QPE和雷达—雨量计降水融合三个部分。首先利用克里金插值方法,对雨量站观测的降水进行插值,得到格点降水信息;再通过局地雨量计订正方法系统性地订正雷达QPE产品,以提高雷达QPE产品精度;最后,结合降水类型,通过雷达—雨量计降水融合算法,产生高时空分辨率、高精度的雷达—雨量计降水融合产品。通过郑州“21·7”暴雨、台风“烟花”和2021年8月随州暴雨三个典型的极端降水个例,对雷达—雨量计降水融合算法产生的雷达—雨量计降水融合产品进行了系统地评估和分析。结果表明,在不同的极端降水个例和不同的降水时段,雷达—雨量计降水融合产品精度上优于雷达QPE产品,且在降水的空间分布上较雨量站观测格点插值产品更能精细地刻画降水的结构特征。表明算法得到的雷达—雨量计降水融合产品的准确性较高,对极端降水有较好地捕捉和监测能力。

关键词：极端降水克里金插值雨量计订正降水融合

维普期刊数据库博看期刊评论

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丹参多酚酸盐对围术期心肌损伤保护临床研究

辽宁中医药大学学报 2018年第3期20卷 104-107页

作者：管笑丹沈阳市第四人民医院

目的：探究丹参多酚酸盐对围术期心肌损伤保护作用的临床疗效。方法：采用随机、单盲、对照原则将PCI术后的稳定型心肌梗死患者168例随机分为使用丹参多酚酸盐治疗组和未使用丹参多酚酸盐对照组,分析比较两组患者术前,术后0、8、16 h心... 详细信息

目的：探究丹参多酚酸盐对围术期心肌损伤保护作用的临床疗效。方法：采用随机、单盲、对照原则将PCI术后的稳定型心肌梗死患者168例随机分为使用丹参多酚酸盐治疗组和未使用丹参多酚酸盐对照组,分析比较两组患者术前,术后0、8、16 h心肌损伤标志物以及CRP变化情况,同时记录两组心脏彩超变化。结果：经SPSS19.0软件统计分析得出治疗组与对照组比较,PCI术后8、16 h测定的肌钙蛋白I、肌酸激酶同工酶、C反应蛋白以及心脏彩超变化有统计学意义（P〈0.05）。结论：丹参多酚酸盐注射液对围术期心肌损伤有保护作用。

关键词：丹参多酚酸盐心肌损伤随机单盲

基于全卷积网络的复杂背景红外弱小目标检测研究

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激光杂志 2024年第4期45卷 254-258页

作者：关晓丹郑东平肖成北华航天工业学院河北廊坊065000

针对复杂背景红外弱小目标检测过程中存在的检测误差率高,检测时间过长等问题,提出基于全卷积网络的复杂背景红外弱小目标检测方法。分析复杂背景红外弱小目标检测的研究进展,找出不同方法的缺陷,采集红外图像,提取目标检测特征,并采用... 详细信息

针对复杂背景红外弱小目标检测过程中存在的检测误差率高,检测时间过长等问题,提出基于全卷积网络的复杂背景红外弱小目标检测方法。分析复杂背景红外弱小目标检测的研究进展,找出不同方法的缺陷,采集红外图像,提取目标检测特征,并采用全卷积网络设计弱小目标检测的分类器,实现复杂背景红外弱小目标检测。实验结果表明,该方法的复杂背景红外弱小目标检测精度超过97%,具有较高的实际应用价值。

关键词：全卷积网络红外弱小目标检测精度提取特征

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研究生专业课课程思政教学改革研究

北华航天工业学院学报 2023年第4期33卷 33-35页

作者：关晓丹何世贤北华航天工业学院电子与控制工程学院河北廊坊065000 廊坊职业技术学院电气工程学院河北廊坊065000

本文对高校研究生专业课课程思政开展模式进行研究,研究如何在进行专业课程教育的过程中进行课程思政。以《航天电子产品装调联技术》课程作为教学改革对象,探讨在研究生专业教育过程中融入思政元素的方式、方法。从课程思政的顶层设计... 详细信息

本文对高校研究生专业课课程思政开展模式进行研究,研究如何在进行专业课程教育的过程中进行课程思政。以《航天电子产品装调联技术》课程作为教学改革对象,探讨在研究生专业教育过程中融入思政元素的方式、方法。从课程思政的顶层设计、思政元素的挖掘方法和代入机制等多个方面对研究生专业教育与思政教育的结合模式进行探讨和实践。

关键词：课程思政研究生专业课教学改革