Hydrologic Response to Future Climate Change in the Dulong-Irra-waddy River Basin Based on Coupled Model Intercomparison Project 6

Within the context of the Belt and Road Initiative(BRI)and the China-Myanmar Economic Corridor(CMEC),the Dulong-Ir-rawaddy(Ayeyarwady)River,an international river among China,India and Myanmar,plays a significant role as both a valuable hydro-power resource and an essential ecological passageway.However,the water resources and security exhibit a high degree of vulnerabil-ity to climate change impacts.This research evaluates climate impacts on the hydrology of the Dulong-Irrawaddy River Basin(DIRB)by using a physical-based hydrologic model.We crafted future climate scenarios using the three latest global climate models(GCMs)from Coupled Model Intercomparison Project 6(CMIP6)under two shared socioeconomic pathways(SSP2-4.5 and SSP5-8.5)for the near(2025-2049),mid(2050-2074),and far future(2075-2099).The regional model using MIKE SHE based on historical hydrologic processes was developed to further project future streamflow,demonstrating reliable performance in streamflow simulations with a val-idation Nash-Sutcliffe Efficiency(NSE)of 0.72.Results showed that climate change projections showed increases in the annual precip-itation and potential evapotranspiration(PET),with precipitation increasing by 11.3%and 26.1%,and PET increasing by 3.2%and 4.9%,respectively,by the end of the century under SSP2-4.5 and SSP5-8.5.These changes are projected to result in increased annual streamflow at all stations,notably at the basin’s outlet(Pyay station)compared to the baseline period(with an increase of 16.1%and 37.0%at the end of the 21st century under SSP2-4.5 and SSP5-8.5,respectively).Seasonal analysis for Pyay station forecasts an in-crease in dry-season streamflow by 31.3%-48.9%and 22.5%-76.3%under SSP2-4.5 and SSP5-8.5,respectively,and an increase in wet-season streamflow by 5.8%-12.6%and 2.8%-33.3%,respectively.Moreover,the magnitude and frequency of flood events are pre-dicted to escalate,potentially impacting hydropower production and food security significantly.This research outlines the hydrological response to future climate change during the 21st century and offers a scientific basis for the water resource management strategies by decision-makers.

Variability of the Pacific subtropical cells under global warming in CMIP6 models

The Pacific subtropical cells(STCs)are shallow meridional overturning circulations connecting the tropics and subtropics,and are assumed to be an important driver of the tropical Pacific decadal variability.The variability of STCs under global warming is investigated using multimodal outputs from the latest phase of the Coupled Model Inter-comparison Project(CMIP6)and ocean reanalysis products.Firstly,the volume transport diagnostic analysis is employed to evaluate how coupled models and ocean reanalysis products reproduce interior STC transport.The variation of heat transport by the interior STC under the high-emissions warming scenarios is also analyzed.The results show that the multimodal-mean linear trends of the interior STC transport along 9°S and 9°N are-0.02 Sv/a and 0.04 Sv/a under global warming,respectively,which is mainly due to the combined effect of the strengthened upper oceanic stratification and the weakening of wind field.There is a compensation relationship between the interior STC and the western boundary transport in the future climate,and the compensation relationship of 9°S is more significant than that of 9°N.In addition,compared with ocean reanalysis products,the coupled models tend to underestimate the variability of the interior STC transport convergence,and thus may lose some sea surface temperature(SST)driving force,which may be the reason for the low STC-SST correlation simulated by the model.The future scenario simulation shows that the heat transport of interior STC is weakened under global warming,with a general agreement across models.

CMIP 6 models simulation of the connection between North/South Pacific Meridional Mode and ENSO

The subtropical North and South Pacific Meridional Modes(NPMM and SPMM)are well known precursors of El Niño-Southern Oscillation(ENSO).However,relationship between them is not constant.In the early 1980,the relationship experienced an interdecadal transition.Changes in this connection can be attributed mainly to the phase change of the Pacific decadal oscillation(PDO).During the positive phase of PDO,a shallower thermocline in the central Pacific is responsible for the stronger trade wind charging(TWC)mechanism,which leads to a stronger equatorial subsurface temperature evolution.This dynamic process strengthens the connection between NPMM and ENSO.Associated with the negative phase of PDO,a shallower thermocline over southeastern Pacific allows an enhanced wind-evaporation-SST(WES)feedback,strengthening the connection between SPMM and ENSO.Using 35 Coupled Model Intercomparison Project Phase 6(CMIP6)models,we examined the NPMM/SPMM performance and its connection with ENSO in the historical runs.The great majority of CMIP6 models can reproduce the pattern of NPMM and SPMM well,but they reveal discrepant ENSO and NPMM/SPMM relationship.The intermodal uncertainty for the connection of NPMM-ENSO is due to different TWC mechanism.A stronger TWC mechanism will enhance NPMM forcing.For SPMM,few models can simulate a good relationship with ENSO.The intermodel spread in the relationship of SPMM and ENSO owing to SST bias in the southeastern Pacific,as WES feedback is stronger when the southeastern Pacific is warmer.

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.

Projected Regional 1.50℃and 2.00℃Warming Threshold-crossing Time Worldwide Using the CMIP6 Models

The Paris Agreement aims to limit global warming to well below 2.00℃and pursue efforts to limit the temperature increase to 1.50℃.However,the response of climate change to unbalanced global warming is affected by spatial and temporal sensitivities.To better understand the regional warming response to global warming at 1.50℃and 2.00℃,we detected the 1.50℃and 2.00℃warming threshold-crossing time(WTT)above pre-industrial levels globally using the Coupled Model Intercomparison Project phase 6(CMIP6)models.Our findings indicate that the 1.50℃or 2.00℃WTT differs substantially worldwide.The warming rate of land would be approximately 1.35–1.46 times that of the ocean between 60°N–60°S in 2015–2100.Consequently,the land would experience a 1.50℃(2.00℃)warming at least 10–20 yr earlier than the time when the global mean near-surface air temperature reaches 1.50℃(2.00℃)WTT.Meanwhile,the Southern Ocean between 0°and 60°S considerably slows down the global 1.50℃and 2.00℃WTT.In 2040–2060,over 98.70%(77.50%),99.70%(89.30%),99.80%(93.40%),and 100.00%(98.00%)of the land will have warmed by over 1.50℃(2.00℃)under SSP(Shared Socioeconomic Pathway)1–2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5,respectively.We conclude that regional 1.50℃(2.00℃)WTT should be fully considered,especially in vulnerable high-latitude and high-altitude regions.

A CMIP6-based assessment of regional climate change in the Chinese Tianshan Mountains

Climate warming profoundly affects hydrological changes,agricultural production,and human society.Arid and semi-arid areas of China are currently displaying a marked trend of warming and wetting.The Chinese Tianshan Mountains(CTM)have a high climate sensitivity,rendering the region particularly vulnerable to the effects of climate warming.In this study,we used monthly average temperature and monthly precipitation data from the CN05.1 gridded dataset(1961-2014)and 24 global climate models(GCMs)of the Coupled Model Intercomparison Project Phase 6(CMIP6)to assess the applicability of the CMIP6 GCMs in the CTM at the regional scale.Based on this,we conducted a systematic review of the interannual trends,dry-wet transitions(based on the standardized precipitation index(SPI)),and spatial distribution patterns of climate change in the CTM during 1961-2014.We further projected future temperature and precipitation changes over three terms(near-term(2021-2040),mid-term(2041-2060),and long-term(2081-2100))relative to the historical period(1961-2014)under four shared socio-economic pathway(SSP)scenarios(i.e.,SSP1-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).It was found that the CTM had experienced significant warming and wetting from 1961 to 2014,and will also experience warming in the future(2021-2100).Substantial warming in 1997 was captured by both the CN05.1 derived from interpolating meteorological station data and the multi-model ensemble(MME)from the CMIP6 GCMs.The MME simulation results indicated an apparent wetting in 2008,which occurred later than the wetting observed from the CN05.1 in 1989.The GCMs generally underestimated spring temperature and overestimated both winter temperature and spring precipitation in the CTM.Warming and wetting are more rapid in the northern part of the CTM.By the end of the 21st century,all the four SSP scenarios project warmer and wetter conditions in the CTM with multiple dry-wet transitions.However,the rise in precipitation fails to counterbalance the drought induced by escalating temperature in the future,so the nature of the drought in the CTM will not change at all.Additionally,the projected summer precipitation shows negative correlation with the radiative forcing.This study holds practical implications for the awareness of climate change and subsequent research in the CTM.

CMIP5/6模式对PDO调制ENSO爆发频率不对称的模拟评估

利用第五次和第六次国际间耦合模式比较计划(CMIP)中piControl情景下的模拟结果,结合观测资料,对比评估了19个CMIP5模式和23个CMIP6模式对太平洋年代际振荡(PDO)调制厄尔尼诺-南方涛动事件爆发频率不对称的模拟能力,并进一步揭示了PDO的调制过程。结果表明:在观测中,PDO正(负)位相下厄尔尼诺(El Niño)的爆发频率比拉尼娜(La Niña)多300%(少73%),53%(78%)的CMIP5(6)模式模拟出这一特征;尽管两个模式整体都低(高)估了PDO正(负)位相的调制能力,但CMIP6模式对PDO调制能力的模拟有所改进。进一步研究发现,在PDO正(负)位相下,赤道太平洋中西部会产生较强的西(东)风异常,风场通过平流的作用使得暖水向东流动,从而在太平洋中东部的海表面温度背景场中出现正(负)异常变化,而这有利于PDO正(负)位相下El Niño(La Niña)事件的发生。

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。

Global air-sea CO_(2) exchange fl ux since 1980s: results from CMIP6 Earth System Models

The ocean could profoundly modulate the ever-increasing atmospheric CO_(2) by air-sea CO_(2) exchange process,which is also able to cause signifi cant changes of physical and biogeochemical properties in return.In this study,we assessed the long-term average and spatial-temporal variability of global air-sea CO_(2) exchange fl ux(F CO_(2))since 1980s basing on the results of 18 Coupled Model Intercomparison Project Phase 6(CMIP6)Earth System Models(ESMs).Our fi ndings indicate that the CMIP6 ESMs simulated global CO_(2) sink in recent three decades ranges from 1.80 to 2.24 Pg C/a,which is coincidence with the results of cotemporaneous observations.What’s more,the CMIP6 ESMs consistently show that the global oceanic CO_(2) sink has gradually intensifi ed since 1980s as well as the observations.This study confi rms the simulated F CO_(2) could reach agreements with the observations in the aspect of primary climatological characteristics,however,the simulation skills of CIMP6 ESMs in diverse open-sea biomes are unevenness.None of the 18 CMIP6 ESMs could reproduce the observed F CO_(2) increasement in the central-eastern tropical Pacifi c and the midlatitude Southern Ocean.Defi ciencies of some CMIP6 ESMs in reproducing the atmospheric pressure systems of the Southern Hemisphere and the El Niño-Southern Oscillation(ENSO)mode of the tropical Pacifi c are probably the major causes.

Evaluation of Arctic sea ice simulation of CMIP6 models from China

Nine coupled climate models from China participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)were evaluated in terms of their capability in ensemble historical Arctic sea ice simulation in the context of 56 CMIP6 models.We evaluated these nine models using satellite observations from 1980 to 2014.This evaluation was conducted comprehensively using 12 metrics covering different aspects of the seasonal cycle and long-term trend of sea ice extent(SIE)and sea ice concentration(SIC).The nine Chinese modelstended to overestimate SIE,especially in March,and underestimate its long-term decline trend.There was less spread in model skill in reproducing the spatial pattern of March SIC than in reproducing the spatial pattern of September SIC.The error of March SIC simulation was distributed at the margins of sea ice cover,such as in the Nordic Seas,the Barents Sea,the Labrador Sea,the Bering Sea,and the Sea of Okhotsk.However,the error of September SIC was distributed both at the margins of sea ice cover and in the central part of the Arctic Basin.Five of these nine models had capabilities comparable with the majority of the CMIP6 models in reproducing the seasonal cycle and long-term trend of Arctic sea ice.

Projection of precipitation extremes over South Asia from CMIP6 GCMs

Extreme precipitation events are one of the most dangerous hydrometeorological disasters,often resulting in significant human and socio-economic losses worldwide.It is therefore important to use current global climate models to project future changes in precipitation extremes.The present study aims to assess the future changes in precipitation extremes over South Asia from the Coupled Model Intercomparison Project Phase 6(CMIP6)Global Climate Models(GCMs).The results were derived using the modified Mann-Kendall test,Sen's slope estimator,student's t-test,and probability density function approach.Eight extreme precipitation indices were assessed,including wet days(RR1mm),heavy precipitation days(RR10mm),very heavy precipitation days(RR20mm),severe precipitation days(RR50mm),consecutive wet days(CWD),consecutive dry days(CDD),maximum 5-day precipitation amount(RX5day),and simple daily intensity index(SDII).The future changes were estimated in two time periods for the 21^(st) century(i.e.,near future(NF;2021-2060)and far future(FF;2061-2100))under two Shared Socioeconomic Pathway(SSP)scenarios(SSP2-4.5 and SSP5-8.5).The results suggest increases in the frequency and intensity of extreme precipitation indices under the SSP5-8.5 scenario towards the end of the 21^(st) century(2061-2100).Moreover,from the results of multimodel ensemble means(MMEMs),extreme precipitation indices of RR1mm,RR10mm,RR20mm,CWD,and SDII demonstrate remarkable increases in the FF period under the SSP5-8.5 scenario.The spatial distribution of extreme precipitation indices shows intensification over the eastern part of South Asia compared to the western part.The probability density function of extreme precipitation indices suggests a frequent(intense)occurrence of precipitation extremes in the FF period under the SSP5-8.5 scenario,with values up to 35.00 d for RR1mm and 25.00-35.00 d for CWD.The potential impacts of heavy precipitation can pose serious challenges to the study area regarding flooding,soil erosion,water resource management,food security,and agriculture development.

Comparative Assessment of Impacts of Future Climate Change on Runoff in Upper Daqinghe Basin,China

Assessing runoff changes is of great importance especially its responses to the projected future climate change on local scale basins because such analyses are generally done on global and regional scales which may lead to generalized conclusions rather than specific ones.Climate change affected the runoff variation in the past in the upper Daqinghe Basin,however,the climate was mainly considered uncertain and still needs further studies,especially its future impacts on runoff for better water resources management and planning.Integrated with a set of climate simulations,a daily conceptual hydrological model(MIKE11-NAM)was applied to assess the impact of climate change on runoff conditions in the Daomaguan,Fuping and Zijingguan basins in the upper Daqinghe Basin.Historical hydrological data(2008–2017)were used to evaluate the applicability of the MIKE11-NAM model.After bias correction,future projected climate change and its impacts on runoff(2025–2054)were analysed and compared to the baseline period(1985–2014)under three shared social economic pathways(SSP1-2.6,SSP2-4.5,and SSP5-8.5)scenarios from Coupled Model Intercomparison Project Phase 6(CMIP6)simulations.The MIKE-11 NAM model was applicable in all three Basins,with both R^(2)and Nash-Sutcliffe Efficiency coefficients greater than 0.6 at daily scale for both calibration(2009–2011)and validation(2012–2017)periods,respectively.Although uncertainties remain,temperature and precipitation are projected to increase compared to the baseline where higher increases in precipitation and temperature are projected to occur under SSP2-4.5 and SSP5-8.5 scenarios,respectively in all the basins.Precipitation changes will range between 12%–19%whereas temperature change will be 2.0℃–2.5℃ under the SSP2-4.5 and SSP5-8.5 scenarios,respectively.In addition,higher warming is projected to occur in colder months than in warmer months.Overall,the runoff of these three basins is projected to respond to projected climate changes differently because runoff is projected to only increase in the Fuping basin under SSP2-4.5 whereas decreases in both Daomaguan and Zijingguan Basins under all scenarios.This study’s findings could be important when setting mitigation strategies for climate change and water resources management.

中国地球系统模式对全球地表入射短波辐射和大气逆辐射的模拟效果评估

以云和地球辐射能量系统(CERES)数据集为准,量化了中国地球系统模式对地表入射短波辐射和大气逆辐射时空变化的模拟性能,明确了多模式间模拟结果存在不确定性的区域。结果表明:中国模式均能模拟出北半球地表入射短波辐射和大气逆辐射“夏高冬低”的季节变化特征。陆地上,中国模式对两个辐射分量月均值的模拟结果与CERES相当,在海洋上低于CERES结果。中国模式能模拟出地表入射短波辐射下降、大气逆辐射上升的年际变化趋势。对于2001—2014年均值,中国模式模拟的地表入射短波辐射在海洋和陆地上较CERES分别偏低3.3和3.0 W·m^(-2),模拟的大气逆辐射在海洋上与CERES结果相当,在陆地上较CERES低1.3 W·m^(-2)。除南北纬30°附近之外,中国模式在其他纬度均低估地表入射短波辐射,以热带和北极最为明显。模式对大气逆辐射的模拟偏差呈纬向波动特征,模拟误差大值出现在高大山脉处。中国模式模拟地表入射短波辐射不确定性极大的区域分布在热带雨林和南极洲沿海,模拟大气逆辐射不确定性极大的区域分布在格林兰岛、青藏高原、安第斯山脉和南极洲沿海。

未来北极夏季陆面气温变化区域特征及其与北大西洋海面温度的关系

未来变暖背景下北极气候变化特征研究具有重要意义,基于国际耦合模式比较计划第六阶段(Coupled Model Intercomparison Project Phase 6,CMIP6)中对北极气候变化模拟能力较好的模式模拟结果,研究SSP2-4.5情景下21世纪北极2 m气温的时空变化特征及其影响因素。结果表明:(1)极地陆地的欧亚大陆(Eurasia, EA)和北美-格陵兰(Greenland, GL)对全球变暖具有不同的响应。EA在21世纪中叶前变暖趋势显著,之后主要表现为年代际尺度的冷暖振荡;GL则始终保持增暖趋势。EA、GL分区气温均存在年际、年代际(10~20 a)尺度上的波动,GL分区还存在20~40 a的准周期变化。(2)前冬北大西洋涛动正位相会引起次年夏季北大西洋呈南北向“-、+、-”三极型海面温度异常,并通过影响大气环流导致EA分区气温正异常,这种影响主要体现在年代际尺度上。(3)北大西洋多年代际振荡为正异常时,北美至格陵兰位势高度偏高,GL分区增暖,并且这种影响在21世纪70年代后更重要;北太平洋北部的海面温度正异常对GL分区增温也有贡献。

CMIP6模式对中国东部地区水循环的模拟能力评估

本文基于观测和再分析资料,采用Brubaker二元模型评估了第六次国际耦合模式比较计划(CMIP6)中19个模式对中国东部季风区气候态水循环过程的模拟能力,并分析了模拟误差来源。结果表明,CMIP6模式集合平均(MME)能够合理再现观测降水和蒸发的年平均气候态空间分布及年循环特征,与观测值的空间相关系数分别为0.92和0.87。较之观测,MME高估了华北地区降水(0.55 mm d^(−1)),低估了华南沿海地区降水(−0.3 mm d^(−1))。所有CMIP6模式均高估蒸发强度(偏差0.03~0.98 mm d^(−1)),使得模拟的降水与蒸发之差偏少。模式整体能够模拟出我国东部季风区降水再循环率及不同边界水汽来源的贡献率,但低估了由南边界进入季风区的水汽贡献,导致东亚季风区偏干。通过分析模式对影响水汽通量的两个气象要素(风速和大气比湿)的模拟能力,发现研究区南边界的风速大小决定了模式间水汽输送差异。南边界风速越大的模式,由南边界进入的水汽通量越大,模式模拟的降水越多。西北太平洋辐合带的东西位置是影响南边界南风速的重要系统之一,辐合带位置偏东的模式模拟的南风强度较弱,使得水汽输送偏弱、降水偏少;反之,南边界水汽输送偏强、降水偏多。本文通过评估最新一代CMIP6模式在东亚水循环方面的模拟性能,指出了当前气候模式在模拟西太平洋辐合带位置方面存在的偏差及其对东亚水循环的影响。

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.

渤海海域渤中19-6潜山气藏成藏要素匹配及成藏模式

为了明确渤海海域渤中19-6潜山千亿立方米气藏的形成过程,基于大量岩心、薄片、测井及地球化学数据,在地质分析的基础上,利用地球化学分析方法和盆地模拟的手段,对其成藏要素及成藏规律进行了系统分析。研究表明:(1)渤中凹陷沙三段烃源岩生气强度普遍超过50×108 m^(3)/km^(2),晚期持续供烃为渤中19-6潜山气藏的形成提供了充足的物质基础;(2)印支期和燕山期构造运动是渤中19-6潜山构造裂缝型储层和潜山圈闭形成的关键时期,并形成了近源断裂输导体系和远源不整合面输导体系;(3)东营组厚层超压泥岩盖层和潜山较弱的晚期构造活动有利于渤中19-6潜山气藏的保存;(4)“生、储、盖、圈、运、保”六大成藏要素的时空匹配,最终导致了渤中19-6潜山千亿立方米大气田的形成。建立了渤中19-6潜山多洼供烃、多向充注、断裂和不整合联合输导的晚期成藏模式。

APPLICATION OF FRF ESTIMATOR BASED ON ERRORS-IN-VARIABLES MODEL IN MULTI-INPUT MULTI-OUTPUT VIBRATION CONTROL SYSTEM

The FRF estimator based on the errors-in-variables （EV） model of multi-input multi-output （MIMO） system is presented to reduce the bias error of FRF HI estimator. The FRF HI estimator is influenced by the noises in the inputs of the system and generates an under-estimation of the true FRF. The FRF estimator based on the EV model takes into account the errors in both the inputs and outputs of the system and would lead to more accurate FRF estimation. The FRF estimator based on the EV model is applied to the waveform replication on the 6-DOF （degree-of-freedom） hydraulic vibration table. The result shows that it is favorable to improve the control precision of the MIMO vibration control system.

基于CMIP 6多模式的长江流域气温、降水与径流预估

【目的】探究未来气候变化对长江流域径流的影响,为长江流域及其他地区的早期洪水预警和防御措施提供依据。【方法】采用国际耦合模式比较计划第6阶段(CMIP 6)多模式集合平均(MME),结合SWAT水文模型,对长江流域1961—2014年气温、降水量和径流等进行评估,并预估了长江流域2020—2099年SSP1-1.9、SSP1-2.6、SSP2-4.5、SSP3-7.0、SSP5-8.5排放情景下的气温、降水量和径流。【结果】(1)相比单一模式,MME历史时期模拟气温和降水效果更好,与观测值的相关系数均大于0.90,MME可以很好地模拟出气温和降水量的空间分布规律。(2)由MME分析可知,2020—2099年长江流域在所有情景下的气温增幅低于50%,降水增量小于20%,在SSP5-8.5情景下模拟的温度值比SSP1-1.9时的温度值高1.23℃,比SSP1-2.6时的温度值高0.99℃。(3)总体上,长江流域未来的年均径流量增加显著,到21世纪末,SSP5-5.8情景下年均径流量将达到40380 m^(3)/s。【结论】本研究揭示了长江流域径流变化趋势与气温与降水之间的相互关系,以及模拟未来气候变化的准确度,同时认为未来长江流域气温、降水量与径流量均呈上升趋势,低碳排放情景下的洪涝灾害相对较少,可为以后长江流域洪涝灾害的预估和区域性气候变化提供依据。

Future Drought Changes in China Projected by the CMIP6 Models:Contributions from Key Factors

Model simulations show that drought may become more severe and widespread in the 21st century due to humaninduced global warming. However, the contributions from the key factors to the model-projected drought changes in China have not yet been examined in detail. We used the self-calibrated Palmer Drought Severity Index with Penman–Monteith potential evapotranspiration(scPDSIpm) based on 10 model simulations selected from the Coupled Model Intercomparison Project Phase 6(CMIP6). We investigated the contributions from precipitation(P), near-surface air temperature and specific humidity [Δ(T + q)], net surface longwave radiation(LW), net surface shortwave radiation(SW), and wind speed(WS) to the future changes in scPDSIpm, including the long-term mean, drying area,probability distribution function(PDF), drought frequency, and drought duration based on the scPDSIpm over China.Our results show that model-projected drying mainly occurs over southern China, whereas the dry areas under drought conditions increase from 20% to about 23%/30% under the two scenarios of the shared socioeconomic pathway(SSP2-4.5/SSP5-8.5) from 1985 to 2100, despite large uncertainties in individual projections partly due to internal variability. Drought frequency is projected to increases by about 10%–54%(15%–88%) under the SSP2-4.5(SSP5-8.5) scenario by the late 21st century, along with increases in drought duration. These changes are accompanied by a decrease in the mean scPDSIpm and flattening of the PDFs. The changes in drying over southern China are mainly attributed to surface warming and the increased surface vapor pressure deficit(VPD), with small contributions from changes in the surface net radiation. The changes in wetting over northern China mostly result from increased precipitation along with a small wetting effect from the changes in wind speed.