Factors responsible for the increasing trend of mei-yu season rainfall during 1979-2020 over the western and eastern mei-yu domain

近几十年来,江淮流域梅雨监测区(MMD)的梅雨期(6-7月)降水呈增加趋势.本文基于1979-2020年台站观测降水资料和ERA5再分析数据,从大气环流变异的角度揭示了这种长期增加趋势的主要影响因素.发现在MMD范围内,梅雨期降水趋势的增幅东部大于西部.水汽收支定量诊断表明,异常的蒸发和水汽平流对MMD西部和东部降水增加趋势的相对贡献是不同的.MMD西部(东部)的降水趋势主要归咎于增强的局地蒸发(增强的垂直水汽平流),后者又取决于MMD对流层中,低层的异常气旋环流.这种位于气候平均的西太平洋副热带高压西北侧的异常气旋有助于MMD东部600 hPa以上的水汽辐散增加,伴随加强的850 hPa水汽辐合,从而导致垂直水汽平流的增强.相反,该异常气旋则有利于增强MMD西部的局地蒸发.

Evaluation of the interannual variability in the East Asian summer monsoon in AMIP and historical experiments of CAS FGOALS-f3-L

对东亚夏季季风(EASM)模拟的评估可以提高我们对亚洲季风动力和气候模拟的理解.在这项研究中,通过使用中国科学院(CAS)全球海洋-大气-陆地系统(FGOALS-f3-L)模式参加的第六次耦合模式相互比较计划(CMIP6)中的大气模式相互比较计划(AMIP)和历史(historical)试验,明确了EASM的年际变率的模拟能力.通过多变量经验正交函数(MV-EOF)分析发现,观测的EASM的主导模态为西太平洋上的太平洋-日本模态,并伴有局部反气旋异常.主导模态的方差贡献率为24.6%.历史(historical)试验可以基本再现这种空间模态,其方差贡献率较AMIP试验更接近于观测.与AMIP试验相比,历史(historical)试验还能更好地模拟EASM变率的时间频率.然而,由于历史(historical)模拟没有在积分开始时应用初始化过程,而AMIP试验受到海表面温度(SST)的约束,因此主成分(PC1)的位相在历史(historical)试验中没有得到较好地再现.进一步分析发现,印度洋和西太平洋热带地区的海气相互作用对EASM的模拟非常重要,而EASM气候变率的模拟可能与厄尔尼诺-南方涛动(ENSO)的模拟能力有关,这值得进一步分析.

1970—2020年黄土高原水蚀风蚀交错区极端降水时空变化研究及驱动因素分析

黄土高原水蚀风蚀交错区作为中国北方典型的生态脆弱区,因其独特地形和气候条件,极端降雨事件对其环境和生态系统的影响更加突出。选取水蚀风蚀交错区28个气象站点,结合RClimDex模型计算11个极端降水指数,采用线性相关分析法、Mann-Kendall趋势检验法和小波交叉法,分析了1970—2020年黄土高原水蚀风蚀交错区极端降水事件时空分布特征,探讨了极端降水事件的驱动因素。结果表明:(1)1970—2020年水蚀风蚀交错区持续干燥日数(CDD)呈下降趋势,其余10个指数呈上升趋势,反映出近50a研究区极端降水事件的频率、量级和强度不断增加。交错区年降水量增加和极端降水事件增加具有密切关系,且极端降水事件增加主要是由中雨日数(R10)和大雨日数(R20)引起。(2)1970—2020年极端降水事件在全区整体为增加趋势,交错区中部和西南部极端降水事件显著发生,陕西段极端降水量和强度呈显著增加趋势且极端化程度更显著。(3)湿日总降水量(PRCPTOT)、暴雨日数(R25)、5d最大降水量(R5d)3个极端降水指数,与影响因子厄尔尼诺-南方涛动(ENSO)、东亚夏季风(EASM)和太阳黑子(SN)具有不同的功率,与SN的交叉小波变换功率最大,说明影响因子中SN和极端降水指数的相关性最高,SN对极端降水事件的影响最大。

CAS FGOALS-f3-L Model Datasets for CMIP6 Historical Atmospheric Model Intercomparison Project Simulation

The outputs of the Chinese Academy of Sciences(CAS) Flexible Global Ocean–Atmosphere–Land System(FGOALS-f3-L) model for the baseline experiment of the Atmospheric Model Intercomparison Project simulation in the Diagnostic,Evaluation and Characterization of Klima common experiments of phase 6 of the Coupled Model Intercomparison Project(CMIP6) are described in this paper. The CAS FGOALS-f3-L model, experiment settings, and outputs are all given. In total,there are three ensemble experiments over the period 1979–2014, which are performed with different initial states. The model outputs contain a total of 37 variables and include the required three-hourly mean, six-hourly transient, daily and monthly mean datasets. The baseline performances of the model are validated at different time scales. The preliminary evaluation suggests that the CAS FGOALS-f3-L model can capture the basic patterns of atmospheric circulation and precipitation well, including the propagation of the Madden–Julian Oscillation, activities of tropical cyclones, and the characterization of extreme precipitation. These datasets contribute to the benchmark of current model behaviors for the desired continuity of CMIP.

Simulation and Improvements of Oceanic Circulation and Sea Ice by the Coupled Climate System Model FGOALS-f3-L

This study documents simulated oceanic circulations and sea ice by the coupled climate system model FGOALS-f3-L developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,under historical forcing from phase 6 of the Coupled Model Intercomparison Project(CMIP6).FGOALS-f3-L reproduces the fundamental features of global oceanic circulations,such as sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),vertical temperature and salinity,and meridional overturning circulations.There are notable improvements compared with the previous version,FGOALS-s2,such as a reduction in warm SST biases near the western and eastern boundaries of oceans and salty SSS biases in the tropical western Atlantic and eastern boundaries,and a mitigation of deep MLD biases at high latitudes.However,several obvious biases remain.The most significant biases include cold SST biases in the northwestern Pacific(over 4°C),freshwater SSS biases and deep MLD biases in the subtropics,and temperature and salinity biases in deep ocean at high latitudes.The simulated sea ice shows a reasonable distribution but stronger seasonal cycle than observed.The spatial patterns of sea ice are more realistic in FGOALS-f3-L than its previous version because the latitude–longitude grid is replaced with a tripolar grid in the ocean and sea ice model.The most significant biases are the overestimated sea ice and underestimated SSS in the Labrador Sea and Barents Sea,which are related to the shallower MLD and weaker vertical mixing.

The FGOALS climate system model as a modeling tool for supporting climate sciences:An overview

Climate system models are useful tools for understanding the interactions among the components of the climate system and predicting/projecting future climate change. The development of climate models has been a central focus of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences(LASG/IAP) since the establishment of the laboratory in 1985. In China, many pioneering component models and fully coupled models of the climate system have been developed by LASG/IAP. The fully coupled climate system developed in the recent decade is named FGOALS(Flexible Global Ocean-Atmosphere-Land System Model). In this paper, an application-oriented review of the LASG/IAP FGOALS model is presented. The improved model performances are demonstrated in the context of cloud-radiation processes, Asian monsoon, ENSO phenomena, Atlantic Meridional Overturning Circulation(AMOC) and sea ice. The FGOALS model has contributed to both CMIP5(Coupled Model Intercomparison Project-phase 5) and IPCC(Intergovernmental Panel on Climate Change) AR5(the Fifth Assessment Report). The release of FGOALS data has supported the publication of nearly 500 papers around the world. The results of FGOALS are cited ~106 times in the IPCC WG1(Working Group 1) AR5. In addition to the traditional long-term simulations and projections, near-term decadal climate prediction is a new set of CMIP experiment, progress of LAGS/IAP in the development of nearterm decadal prediction system is reviewed. The FGOALS model has supported many Chinese national-level research projects and contributed to the national climate change assessment report. The crucial role of FGOALS as a modeling tool for supporting climate sciences is highlighted by demonstrating the model's performances in the simulation of the evolution of Earth's climate from the past to the future.

CAS-FGOALS Datasets for the Two Interglacial Epochs of the Holocene and the Last Interglacial in PMIP4

Two versions of the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System model(CASFGOALS),version f3-L and g3,are used to simulate the two interglacial epochs of the mid-Holocene and the Last Interglacial in phase 4 of the Paleoclimate Modelling Intercomparison Project(PMIP4),which aims to study the impact of changes in orbital parameters on the Earth’s climate.Following the PMIP4 experimental protocols,four simulations for the mid-Holocene and two simulations for the Last Interglacial have been completed,and all the data,including monthly and daily outputs for the atmospheric,oceanic,land and sea-ice components,have been released on the Earth System Grid Federation(ESGF)node.These datasets contribute to PMIP4 and CMIP6(phase 6 of the Coupled Model Intercomparison Project)by providing the variables necessary for the two interglacial periods.In this paper,the basic information of the CAS-FGOALS models and the protocols for the two interglacials are briefly described,and the datasets are validated using proxy records.Results suggest that the CAS-FGOALS models capture the large-scale changes in the climate system in response to changes in solar insolation during the interglacial epochs,including warming in mid-to-high latitudes,changes in the hydrological cycle,the seasonal variation in the extent of sea ice,and the damping of interannual variabilities in the tropical Pacific.Meanwhile,disagreements within and between the models and the proxy data are also presented.These datasets will help the modeling and the proxy data communities with a better understanding of model performance and biases in paleoclimate simulations.

Overview of the CMIP6 Historical Experiment Datasets with the Climate System Model CAS FGOALS-f3-L

The three-member historical simulations by the Chinese Academy of Sciences Flexible Global Ocean–Atmosphere–Land System model,version f3-L(CAS FGOALS-f3-L),which is contributing to phase 6 of the Coupled Model Intercomparison Project(CMIP6),are described in this study.The details of the CAS FGOALS-f3-L model,experiment settings and output datasets are briefly introduced.The datasets include monthly and daily outputs from the atmospheric,oceanic,land and sea-ice component models of CAS FGOALS-f3-L,and all these data have been published online in the Earth System Grid Federation(ESGF,https://esgf-node.llnl.gov/projects/cmip6/).The three ensembles are initialized from the 600th,650th and 700th model year of the preindustrial experiment(piControl)and forced by the same historical forcing provided by CMIP6 from 1850 to 2014.The performance of the coupled model is validated in comparison with some recent observed atmospheric and oceanic datasets.It is shown that CAS FGOALS-f3-L is able to reproduce the main features of the modern climate,including the climatology of air surface temperature and precipitation,the long-term changes in global mean surface air temperature,ocean heat content and sea surface steric height,and the horizontal and vertical distribution of temperature in the ocean and atmosphere.Meanwhile,like other state-of-the-art coupled GCMs,there are still some obvious biases in the historical simulations,which are also illustrated.This paper can help users to better understand the advantages and biases of the model and the datasets。

Formation and Variation of the Atmospheric Heat Source over the Tibetan Plateau and Its Climate Effects

To cherish the memory of the late Professor Duzheng YE on what would have been his 100 th birthday, and to celebrate his great accomplishment in opening a new era of Tibetan Plateau（TP） meteorology, this review paper provides an assessment of the atmospheric heat source（AHS） over the TP from different data resources, including observations from local meteorological stations, satellite remote sensing data, and various reanalysis datasets. The uncertainty and applicability of these heat source data are evaluated. Analysis regarding the formation of the AHS over the TP demonstrates that it is not only the cause of the atmospheric circulation, but is also a result of that circulation. Based on numerical experiments, the review further demonstrates that land–sea thermal contrast is only one part of the monsoon story. The thermal forcing of the Tibetan–Iranian Plateau plays a significant role in generating the Asian summer monsoon（ASM）, i.e., in addition to pumping water vapor from sea to land and from the lower to the upper troposphere, it also generates a subtropical monsoon–type meridional circulation subject to the angular momentum conservation, providing an ascending-air large-scale background for the development of the ASM.

CAS FGOALS-f3-L Large-ensemble Simulations for the CMIP6 Polar Amplification Model Intercomparison Project

Large-ensemble simulations of the atmosphere-only time-slice experiments for the Polar Amplification Model Intercomparison Project(PAMIP)were carried out by the model group of the Chinese Academy of Sciences(CAS)Flexible Global Ocean-Atmosphere-Land System(FGOALS-f3-L).Eight groups of experiments forced by different combinations of the sea surface temperature(SST)and sea ice concentration(SIC)for pre-industrial,present-day,and future conditions were performed and published.The time-lag method was used to generate the 100 ensemble members,with each member integrating from 1 April 2000 to 30 June 2001 and the first two months as the spin-up period.The basic model responses of the surface air temperature(SAT)and precipitation were documented.The results indicate that Arctic amplification is mainly caused by Arctic SIC forcing changes.The SAT responses to the Arctic SIC decrease alone show an obvious increase over high latitudes,which is similar to the results from the combined forcing of SST and SIC.However,the change in global precipitation is dominated by the changes in the global SST rather than SIC,partly because tropical precipitation is mainly driven by local SST changes.The uncertainty of the model responses was also investigated through the analysis of the large-ensemble members.The relative roles of SST and SIC,together with their combined influence on Arctic amplification,are also discussed.All of these model datasets will contribute to PAMIP multi-model analysis and improve the understanding of polar amplification.

CAS FGOALS-f3-H Dataset for the High-Resolution Model Intercomparison Project(HighResMIP)Tier 2

Following the High-Resolution Model Intercomparison Project(HighResMIP)Tier 2 protocol under the Coupled Model Intercomparison Project Phase 6(CMIP6),three numerical experiments are conducted with the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System Model,version f3-H(CAS FGOALS-f3-H),and a 101-year(1950–2050)global high-resolution simulation dataset is presented in this study.The basic configuration of the FGOALSf3-H model and numerical experiments design are briefly described,and then the historical simulation is validated.Forced by observed radiative agents from 1950 to 2014,the coupled model essentially reproduces the observed long-term trends of temperature,precipitation,and sea ice extent,as well as the large-scale pattern of temperature and precipitation.With an approximate 0.25°horizontal resolution in the atmosphere and 0.1°in the ocean,the coupled models also simulate energetic western boundary currents and the Antarctic Circulation Current(ACC),reasonable characteristics of extreme precipitation,and realistic frontal scale air-sea interaction.The dataset and supporting detailed information have been published in the Earth System Grid Federation.

LASG Global AGCM with a Two-moment Cloud Microphysics Scheme:Energy Balance and Cloud Radiative Forcing Characteristics

Cloud dominates influence factors of atmospheric radiation, while aerosol–cloud interactions are of vital importance in its spatiotemporal distribution. In this study, a two-moment(mass and number) cloud microphysics scheme, which significantly improved the treatment of the coupled processes of aerosols and clouds, was incorporated into version 1.1 of the IAP/LASG global Finite-volume Atmospheric Model(FAMIL1.1). For illustrative purposes, the characteristics of the energy balance and cloud radiative forcing(CRF) in an AMIP-type simulation with prescribed aerosols were compared with those in observational/reanalysis data. Even within the constraints of the prescribed aerosol mass, the model simulated global mean energy balance at the top of the atmosphere(TOA) and at the Earth’s surface, as well as their seasonal variation, are in good agreement with the observational data. The maximum deviation terms lie in the surface downwelling longwave radiation and surface latent heat flux, which are 3.5 W m-2(1%) and 3 W m-2(3.5%), individually. The spatial correlations of the annual TOA net radiation flux and the net CRF between simulation and observation were around 0.97 and 0.90, respectively. A major weakness is that FAMIL1.1 predicts more liquid water content and less ice water content over most oceans. Detailed comparisons are presented for a number of regions, with a focus on the Asian monsoon region(AMR). The results indicate that FAMIL1.1 well reproduces the summer–winter contrast for both the geographical distribution of the longwave CRF and shortwave CRF over the AMR. Finally, the model bias and possible solutions, as well as further works to develop FAMIL1.1 are discussed.

Datasets for the CMIP6 Scenario Model Intercomparison Project (ScenarioMIP) Simulations with the Coupled Model CAS FGOALS-f3-L

The datasets for the tier-1 Scenario Model Intercomparison Project(ScenarioMIP)experiments from the Chinese Academy of Sciences(CAS)Flexible Global Ocean-Atmosphere-Land System model,finite-volume version 3(CAS FGOALS-f3-L)are described in this study.ScenarioMIP is one of the core MIP experiments in phase 6 of the Coupled Model Intercomparison Project(CMIP6).Considering future CO2,CH4,N2O and other gases’concentrations,as well as land use,the design of ScenarioMIP involves eight pathways,including two tiers(tier-1 and tier-2)of priority.Tier-1 includes four combined Shared Socioeconomic Pathways(SSPs)with radiative forcing,i.e.,SSP1-2.6,SSP2-4.5,SSP3-7.0 and SSP5-8.5,in which the globally averaged radiative forcing at the top of the atmosphere around the year 2100 is approximately 2.6,4.5,7.0 and 8.5 W m−2,respectively.This study provides an introduction to the ScenarioMIP datasets of this model,such as their storage location,sizes,variables,etc.Preliminary analysis indicates that surface air temperatures will increase by about 1.89℃,3.07℃,4.06℃ and 5.17℃ by around 2100 under these four scenarios,respectively.Meanwhile,some other key climate variables,such as sea-ice extension,precipitation,heat content,and sea level rise,also show significant long-term trends associated with the radiative forcing increases.These datasets will help us understand how the climate will change under different anthropogenic and radiative forcings.

Interannual Influences of the Surface Potential Vorticity Forcing over the Tibetan Plateau on East Asian Summer Rainfall

The influences of interannual surface potential vorticity forcing over the Tibetan Plateau(TP)on East Asian summer rainfall(EASR)and upper-level circulation are explored in this study.The results show that the interannual EASR and associated circulations are closely related to the surface potential vorticity negative uniform leading mode(PVNUM)over the TP.When the PVNUM is in the positive phase,more rainfall occurs in the Yangtze River valley,South Korea,Japan,and part of northern China,less rainfall occurs in southern China,and vice versa.A possible mechanism by which PVNUM affects EASR is proposed.Unstable air induced by the positive phase of PVNUM could stimulate significant upward motion and a lower-level anomalous cyclone over the TP.As a result,a dipole heating mode with anomalous cooling over the southwestern TP and anomalous heating over the southeastern TP is generated.Sensitivity experiment results regarding this dipole heating mode indicate that anomalous cooling over the southwestern TP leads to local and northeastern Asian negative height anomalies,while anomalous heating over the southeastern TP leads to local positive height anomalies.These results greatly resemble the realistic circulation pattern associated with EASR.Further analysis indicates that the anomalous water vapor transport associated with this anomalous circulation pattern is responsible for the anomalous EASR.Consequently,changes in surface potential vorticity forcing over the TP can induce changes in EASR.

不同植被空间配置下的坡面产沙及泥沙连通性变化特征

植被是影响土壤侵蚀的重要因子,探讨坡面产沙和泥沙连通性对植被分布的响应对揭示土壤侵蚀过程机理及预测坡面侵蚀具有重要意义。通过室内人工放水冲刷试验,分析3种植被布设位置(坡上、坡中、坡下)在不同冲刷流量(3.2,5.2 L/min)和不同覆盖度(0,30%,50%,70%)下的减沙效益,结合坡面产沙潜力指数探究植被覆盖影响下的泥沙连通性变化特征。结果表明:(1)从不同盖度下的平均减沙效益及其稳定性来看,植被布局的减沙效益随盖度变化,且坡下植被空间分布最优。随冲刷流量增加,不同植被布局间的减沙效益差距缩小;(2)当植被盖度≤30%时,冲刷流量对坡面产沙的影响贡献较大;随盖度增加,植被的影响贡献程度大于冲刷流量,成为影响坡面侵蚀的主要因素;(3)坡面产沙潜力指数在不同植被盖度和分布位置下表现出明显差异。随盖度增加,产沙潜力指数减小,泥沙连通性减弱;坡下布设植被相比坡上和坡中产沙潜力指数最小,泥沙连通性最弱。该指数与产沙量之间存在显著的正相关关系,即产沙潜力越大,泥沙连通性越强,产沙量越大。研究结果可为深入探索土壤侵蚀机理及植被的生态效益提供科学依据,为黄土高原地区的生态建设提供参考。

CAS FGOALS-f3-L Model Datasets for CMIP6 DCPP Experiment

The outputs of the Chinese Academy of Sciences(CAS)Flexible Global Ocean-Atmosphere-Land System(FGOALSf3-L)model for the decadal climate prediction project(DCPP)of the Coupled Model Intercomparison Project Phase 6(CMIP6)are described in this paper.The FGOALS-f3-L was initialized through the upgraded,weakly coupled data assimilation scheme,referred to as EnOI-IAU,which assimilates observational anomalies of sea surface temperature(SST)and upper-level(0–1000-m)ocean temperature and salinity profiles into the coupled model.Then,nine ensemble members of 10-year hindcast/forecast experiments were conducted for each initial year over the period of 1960–2021,based on initial conditions produced by three initialization experiments.The hindcast and forecast experiments follow the experiment designs of the Component-A and Component-B of the DCPP,respectively.The decadal prediction output datasets contain a total of 44 monthly mean atmospheric and oceanic variables.The preliminary evaluation indicates that the hindcast experiments show significant predictive skill for the interannual variations of SST in the north Pacific and multi-year variations of SST in the subtropical Pacific and the southern Indian Ocean.

延河流域泥沙连通性对土地利用变化的响应

泥沙连通性是表征泥沙在地貌单元间物理级联关系的重要参数,探讨其对土地利用变化的响应,对揭示流域内部水沙动态以及不同土地利用类型的水土保持效应具有重要意义。基于延河流域1990—2019年土地利用与径流输沙量等数据资料,结合连通性指数(index of connectivity,IC)分析土地利用变化对泥沙连通性时空分布的影响及与径流输沙量的关系。结果表明:1)近30年来,延河流域土地利用变化以退耕还林还草为主,加之少量的建设用地扩张。2)1990—2019年,延河流域IC整体呈下降趋势,截至2019年降低17.85%。退耕还林还草和建设用地扩张可有效降低泥沙连通程度,且退耕还林还草具有长期生态效益。3)IC存在明显的空间分异规律,呈现由南向北、由东向西的增加趋势。流域中部是主要退耕还林还草区和建设用地扩张区,也是泥沙连通性明显下降区;流域西北部泥沙连通性较高,且随土地利用变化降幅较小;流域南部泥沙连通性低。4)IC与输沙量之间存在显著正相关关系(P<0.05),适用于流域输沙预测。研究成果可为深入理解流域泥沙输移过程提供科学依据,并为布局和优化土地利用提供参考。

关于CAS FGOALS-f3-L模式中青藏高原地表温度偏差的归因分析

中国科学院全球海洋-大气-陆地耦合模式(FGOALS-f3-L)参加了耦合模式比较计划的第六阶段(CMIP6)试验,但是其对关键气候敏感地区青藏高原的地表温度的再现能力还不清楚.这项研究用再分析资料CFSR评估了FGOALSf3-L模式对青藏高原地表温度的再现能力.结果表明,FGOALS-f3-L可以合理模拟整个高原上年平均地表温度的空间分布,但低估了整个高原上年平均地表温度.模拟的地表温度在整个高原上冬春季表现为冷偏差,夏秋季表现为暖偏差.基于地表能量平衡方程的进一步定量分析表明,地表反照率反馈(SAF)项极大地贡献了高原西部年平均,冬春季平均地表温度的冷偏差,而对高原东部是暖偏差贡献.与SAF项相比,地表感热项对地表温度偏差的贡献几乎相反,这大大抵消了SAF项引起的偏差.云辐射强迫项对高原东部的年平均和季节平均弱冷偏差有很大贡献.与高估的水蒸气含量有关的长波辐射项造成了夏秋季整个高原上大部分的暖偏差.该研究表明,提高FGOALS-f3-L中的陆面和云过程对降低高原上地表温度偏差至关重要.

氢键作用对沥青质超分子聚集的影响

对沥青质进行羧基化、磺化和甲基化反应,从加强与钝化氢键作用两个方面对比研究了不同化学处理对沥青质结构、热稳定性以及沥青质聚集的影响。研究发现:羧基、磺酸基等基团引入沥青质分子后,提高了沥青质分子的极性,增强了分子间的氢键作用,显著促进了沥青质的聚集,并且引入的基团极性越强,促进聚集效果越明显;相反,沥青质中含活泼氢官能团被甲基化后,甲基的引入屏蔽了形成氢键作用的基团,降低了沥青质聚集体形成过程中的氢键数量,从而削弱了沥青质的聚集。实验结果直观地证明了氢键作用对沥青质聚集体形成的影响,揭示了甲基化、羧基化及磺化反应影响沥青质聚集的机理。

石油沥青质超分子聚集及解聚研究进展

石油沥青质组成复杂,氢/碳原子比低,硫、氮等杂原子含量高,给石油开采、运输和加工处理带来困难,究其原因是石油沥青质分子结构复杂,极易发生超分子聚集,形成聚集体。目前对沥青质超分子聚集的认识越来越广泛,并被石油化学工作者广泛接受。沥青质超分子聚集是通过电荷转移作用、偶极作用以及氢键作用形成沥青质分子之间的缔合,这些弱相互作用在石油体系的分子间普遍存在,实现沥青质聚集体的解聚是重质油高效轻质化的基础。研究表明,采用化学方法改变沥青质分子结构或采用物理方法改变沥青质物理状态,均能在一定程度上使得沥青质聚集体解聚。