基于CMIP6模式优化集合平均预估21世纪全球陆地生态系统总初级生产力变化   总被引：1，自引：0，他引：1  

黄禄丰  朱再春  黄萌田  赵茜  马伟蕊  曾辉 《气候变化研究进展》2021,17(5):514-524

利用国际耦合模式比较计划第六阶段(CMIP6)中18个地球系统模式总初级生产力(GPP)模拟数据,基于传统的多模式集合平均(MME)和可靠集合平均方法(REA),在4个未来情景(SSP1-2.6,SSP2-4.5,SSP3-7.0和SSP5-8.5)下预估了21世纪全球陆地生态系统GPP的变化量,并分析了GPP变化的驱动因子。研究结果表明：在4个未来情景下,基于REA方法预估的全球陆地生态系统年GPP在未来时期(2068—2100年)比历史时期(1982—2014年)分别增长了(14.85±3.32)、(28.43±4.97)、(37.66±7.61)和(45.89±9.21)Pg C,其增量大小和不确定性都明显低于MME方法。在4个情景下,大气CO₂浓度增长对GPP变化的贡献最大,基于REA方法计算的贡献占比分别为140%、137%、115%和75%;除SSP5-8.5(24%)外,其他情景下升温均导致全球陆地生态系统GPP降低(-42%、-37%、-16%),部分抵消了CO₂施肥效应的正面贡献。温度的影响存在纬度差异：升温在低纬度地区对GPP有负向贡献,在中高纬度地区为正向贡献。降水和辐射变化对GPP变化的贡献相对较小。  相似文献   

应对气候变化进程中纳入性别考虑的进展与启示     

刘蕾 《气候变化研究进展》2021,17(5):548-558

女性在应对气候变化中处于不利地位,也是应对气候变化中不可忽视的力量。国际社会已逐渐认识到在应对气候变化进程中纳入性别考虑的重要意义,性别议题在气候谈判中的主流化趋势明显,《联合国气候变化框架公约》执行层面纳入性别考虑取得了长足的进展,以全球环境基金、绿色气候基金为代表的《联合国气候变化框架公约》资金机制已将性别政策纳入机构政策体系,并积极在项目层面推动性别政策的实施。虽然国际气候变化领域的性别主流化工作取得了较大进展,但仍存在女性参与气候变化决策的程度不足、减缓领域纳入性别考虑的程度不足等问题。目前中国气候变化领域对性别的关注不足,建议加强气候变化领域的性别问题研究,为履约工作提供支撑;在应对气候变化相关的政策体系中纳入性别考虑,加强与性别领域的沟通协作;加强气候变化相关机构性别主流化能力建设,明确职责安排;加强气候变化领域国内项目、“一带一路”项目和“南南合作”项目的性别主流化;切实加强中国女性应对气候变化能力,提高女性对气候行动的参与度。  相似文献   

IPCC AR6报告解读：气候系统对太阳辐射干预响应     

曹龙 《气候变化研究进展》2021,17(6):671-684

IPCC第六次评估报告（AR6）第一工作组报告评估了太阳辐射干预（Solar radiation modification,SRM）对气候系统和碳循环的影响。在大幅度减排基础上,太阳辐射干预有潜力作为应对气候变化的备用措施。目前,对于太阳辐射干预气候影响的评估都是基于模式模拟结果。评估主要结论如下：太阳辐射干预可以在全球和区域尺度上抵消一部分温室气体增加造成的气候变化（高信度);但是太阳辐射干预无法在全球和区域尺度上完全抵消温室气体增加引起的气候变化（几乎确定);有可能通过适当的太阳辐射干预设计,同时实现多个温度变化减缓目标（中等信度);在高强度温室气体排放情景下,如果太阳辐射干预实施后突然终止,并且这种终止长时间持续,将会造成快速的气候变化（高信度);如果在减排和CO₂移除的情况下,太阳辐射干预的实施强度逐渐减小至零,将显著降低太阳辐射干预突然终止产生的快速气候变化风险（中等信度);太阳辐射干预会通过降温作用,促进陆地和海洋对大气CO₂的吸收（中等信度),但是太阳辐射干预无法缓解海洋酸化（高信度);太阳辐射干预对其他生物化学循环影响的不确定性大。由于对云-气溶胶-辐射过程的相互作用和微物理过程认知有限,目前对平流层气溶胶注入、海洋低云亮化、高层卷云变薄等太阳辐射干预方法的冷却潜力和气候效应的认知还有很大的不确定性。  相似文献   

A CRPS-Based Spatial Technique for the Verification of Ensemble Precipitation Forecasts     

赵滨  张博  李子良 《热带气象学报(英文版)》2021,27(1):24-33

Traditional precipitation skill scores are affected by the well-known“double penalty”problem caused by the slight spatial or temporal mismatches between forecasts and observations. The fuzzy (neighborhood) method has been proposed for deterministic simulations and shown some ability to solve this problem. The increasing resolution of ensemble forecasts of precipitation means that they now have similar problems as deterministic forecasts. We developed an ensemble precipitation verification skill score, i.e., the Spatial Continuous Ranked Probability Score (SCRPS), and used it to extend spatial verification from deterministic into ensemble forecasts. The SCRPS is a spatial technique based on the Continuous Ranked Probability Score (CRPS) and the fuzzy method. A fast binomial random variation generator was used to obtain random indexes based on the climatological mean observed frequency, which were then used in the reference score to calculate the skill score of the SCRPS. The verification results obtained using daily forecast products from the ECMWF ensemble forecasts and quantitative precipitation estimation products from the OPERA datasets during June-August 2018 shows that the spatial score is not affected by the number of ensemble forecast members and that a consistent assessment can be obtained. The score can reflect the performance of ensemble forecasts in modeling precipitation and thus can be widely used.  相似文献   

对IPCC第六次评估报告中有关干旱变化的解读   总被引：1，自引：0，他引：1       下载免费PDF全文

姜大膀  王晓欣 《大气科学学报》2021,44(5):650-653

政府间气候变化专门委员会（IPCC）于2021年8月发布了第六次评估报告（AR6）自然科学基础卷的决策者摘要,主要对自2013年第五次评估报告（AR5）以来的气候变化科学研究进展进行了系统的评估,并使用新一代气候模式在新的共享社会经济路径情景下对未来气候变化进行了预估。本文基于AR5和AR6相关章节素材,解读了干旱变化的评估结论。  相似文献   

The Digital Belt and Road program in support of regional sustainability     

Huadong Guo  Yubao Qiu  Massimo Menenti  Fang Chen  Paul F. Uhlir 《International Journal of Digital Earth》2018,11(7):657-669

The Belt and Road initiative has a significant focus on infrastructure, trade, and economic development across a vast region, and it also provides significant opportunities for sustainable development. The combined pressure of climate variability, intensified use of resources, and the fragility of ecosystems make it very challenging, however, to achieve future sustainability. To develop the path in a sustainable way, it is important to have a comprehensive understanding of these issues across nations and evaluate them in a scientific and well-informed approach. In this context, the Digital Belt and Road (DBAR) program was initiated as an international venture to share expertise, knowledge, technologies, and data to demonstrate the role of Earth observation science and technology and big Earth data applications to support large-scale development. In this paper, we identify pressing challenges, present the research priorities and foci of the DBAR program, and propose solutions where big Earth data can make significant contributions. This paper calls for further joint actions and collaboration to build a digital silk road in support of sustainable development at national, regional and global levels.  相似文献   

Geometric-constrained multi-view image matching method based on semi-global optimization     

Wenhao Zhao  Li Yan 《地球空间信息科学学报》2018,21(2):115-126

Targeting at a reliable image matching of multiple remote sensing images for the generation of digital surface models, this paper presents a geometric-constrained multi-view image matching method, based on an energy minimization framework. By employing a geometrical constraint, the cost value of the energy function was calculated from multiple images, and the cost value was aggregated in an image space using a semi-global optimization approach. A homography transform parameter calculation method is proposed for fast calculation of projection pixel on each image when calculating cost values. It is based on the known interior orientation parameters, exterior orientation parameters, and a given elevation value. For an efficient and reliable processing of multiple remote sensing images, the proposed matching method was performed via a coarse-to-fine strategy through image pyramid. Three sets of airborne remote sensing images were used to evaluate the performance of the proposed method. Results reveal that the multi-view image matching can improve matching reliability. Moreover, the experimental results show that the proposed method performs better than traditional methods.  相似文献   

Super-resolution enhancement of UAV images based on fractional calculus and POCS     

Junfeng Lei  Shangyue Zhang  Li Luo  He Wang 《地球空间信息科学学报》2018,21(1):56-66

Abstract

A super-resolution enhancement algorithm was proposed based on the combination of fractional calculus and Projection onto Convex Sets (POCS) for unmanned aerial vehicles (UAVs) images. The representative problems of UAV images including motion blur, fisheye effect distortion, overexposed, and so on can be improved by the proposed algorithm. The fractional calculus operator is used to enhance the high-resolution and low-resolution reference frames for POCS. The affine transformation parameters between low-resolution images and reference frame are calculated by Scale Invariant Feature Transform (SIFT) for matching. The point spread function of POCS is simulated by a fractional integral filter instead of Gaussian filter for more clarity of texture and detail. The objective indices and subjective effect are compared between the proposed and other methods. The experimental results indicate that the proposed method outperforms other algorithms in most cases, especially in the structure and detail clarity of the reconstructed images.  相似文献   

Modelling coastal land use change by incorporating spatial autocorrelation into cellular automata models   总被引：1，自引：0，他引：1  

Yongjiu Feng  Qianqian Yang  Zhonghua Hong  Li Cui 《国际地球制图》2018,33(5):470-488

This paper presents a spatial autoregressive (SAR) method-based cellular automata (termed SAR-CA) model to simulate coastal land use change, by incorporating spatial autocorrelation into transition rules. The model captures the spatial relationships between explained and explanatory variables and then integrates them into CA transition rules. A conventional CA model (LogCA) based on logistic regression (LR) was studied as a comparison. These two CA models were applied to simulate urban land use change of coastal regions in Ningbo of China from 2000 to 2015. Compared to the LR method, the SAR model yielded smaller accumulated residuals that showed a random distribution in fitting the CA transition rules. The better-fitting SAR model performed well in simulating urban land use change and scored an overall accuracy of 85.3%, improving on the LogCA model by 3.6%. Landscape metrics showed that the pattern generated by the SAR-CA model has less difference with the observed pattern.  相似文献   

西藏班戈错水菱镁矿藻类成矿实验及其成因分析     

蒋天明  姬连敏  程怀德  李斌凯  李刚  马海州  张西营  李长忠  马学海  张鹏程 《地质论评》2021,67(5):67060004-67060004

目前关于天然水菱镁矿的形成认识主要有蒸发沉积成因和生物成因两类。前人在室内成功制备出水菱镁矿矿物,证实了该矿物的无机成因理论,但是实验结晶条件明显高于西藏班戈错的寒冷气候条件和水化学条件,并且班戈错湖水通过自然蒸发结晶也难以形成水菱镁矿矿物,而这一认识与周边阶地上正在形成水菱镁矿的现象相矛盾。因此,自然蒸发沉积可能不是现阶段班戈错水菱镁矿的主要形成过程,而已有研究表明,藻类具备诱导形成碳酸盐矿物的能力,本文利用西藏班戈错Ⅲ湖湖水及其藻类开展室内模拟实验,并与无藻类的湖水自然结晶结果相对照,探讨藻类生命活动与班戈错水菱镁矿的成因联系。研究发现,藻类不仅能够适应高盐度盐水环境（矿化度117.3 g/L）,并且在其光合作用过程中还能显著提高周围水体pH值（最高可达10.564）,诱导并促进球碳镁石在藻类网状节点处结晶沉淀,该矿物进一步脱水即能够形成水菱镁矿矿物;而人为提高班戈错Ⅲ湖湖水Mg2+浓度也仅能结晶形成三水菱镁矿矿物,无球碳镁石或水菱镁矿结晶析出。因此,西藏班戈错水菱镁矿的形成过程与藻类生物成矿作用密切相关,但是有关球碳镁石向水菱镁矿转变的具体条件以及藻类成矿作用的具体分子机制仍不清楚,有待于进一步研究。  相似文献