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.

Multi-dimensional Simulation of Phase Change by a 0D-2D Model Coupling via Stefan Condition

Considering phase changes associated with a high-temperature molten material cooled down from the outside,this work presents an improvement of the modelling and the numerical simulation of such processes for an application pertaining to the safety of light water nuclear reactors.Postulating a core meltdown accident,the behaviour of the core melt(aka corium)into a steel vessel is of tremendous importance when evaluating the vessel integrity.Evaluating correctly the heat fluxes requires the numerical simulation of the interaction between the liquid material and its solid counterpart which forms during the solidification process,but also may melt back.To simulate this configuration,encoun-tered in various industrial applications,one considers a bi-phase model constituted by a liquid phase in contact and interaction with its solid phase.The liquid phase may solidify in presence of low energetic source,while the solid phase may melt due to an intense heat flux from the high-temperature liquid.In the frame of the in-house legacy code,several simplifying assumptions(0D multi-layer discretization,instantaneous heat transfer via a quadratic temperature profile in solids)are made for the modelling of such phase changes.In the present work,these shortcomings are illustrated and further overcome by solving a 2D heat conduction model in the solid by a mixed Raviart-Thomas finite element method coupled to the liquid phase due to heat and mass exchanges through Stefan condition.The liquid phase is modeled with a 0D multi-layer approach.The 0D-liquid and 2D-solid mod-els are coupled by a Stefan like phase change interface model.Several sanity checks are performed to assess the validity of the approach on 1D and 2D academical configurations for which exact or reference solutions are available.Then more advanced situations(genu-ine multi-dimensional phase changes and an"industrial-like scenario")are simulated to verify the appropriate behavior of the obtained coupled simulation scheme.

Changes of Air–sea Coupling in the North Atlantic over the 20th Century

Changes of air–sea coupling in the North Atlantic Ocean over the 20 th century are investigated using reanalysis data,climate model simulations, and observational data. It is found that the ocean-to-atmosphere feedback over the North Atlantic is significantly intensified in the second half of the 20 th century. This coupled feedback is characterized by the association between the summer North Atlantic Horseshoe（NAH） SST anomalies and the following winter North Atlantic Oscillation（NAO）. The intensification is likely associated with the enhancement of the North Atlantic storm tracks as well as the NAH SST anomalies. Our study also reveals that most IPCC AR4 climate models fail to capture the observed NAO/NAH coupled feedback.

Devonian Sea-Level Change Rhythms in South China and Coupling Relationships Among the Earth-spheres

Twenty orthosequences and their corresponding sea-level change (SLC) cycles have been recognized in the Devonian overlying the Caledonian unconformity, of which 9, 5.5 and 5.5 occurred in the Lower, Middle and Upper Devonian respectively. They can be grouped into 4 orthosequence sets, in which the maximum flooding surfaces lie in the sulcutus Zone (D12), perbonus Zone (D13), Middle and Upper varcus Zone (D22) and gigas Zone (D21) respectively. Four instant palaeogeographical reconstructions of South China have been made in the Emsian and Givetian. Devonian sea-level change rhythms of South China can be divided into 3 categories: the autorhythmic, the worldwide and regional allorhythmic, and the coupling-rhythmic. They developed respectively in the Famennian, Pragian, Eifelian, Lochkovian, Emsian, Givetian, Frasnian and the F / F (between the Frasnian and Famennian) event. The cause of the worldwide allorhythmic SLC of the Pragian and Eifelian under comparatively dry, warm and tranquil conditions may be related to the pulsating expanding and contracting of the oceanic basin volume or the earth volume pulsation, rather than the common glaciation and plate tectonism. The coupling-rhythmic SLC related to the F/ F event is a sensitive indicator of the interaction between terrestrial and extraterrestrial factors, and coordinated action among the earth-spheres.

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.

Multi-scenario Simulation and Spatial-temporal Analysis of LUCC in China's Coastal Zone Based on Coupled SD-FLUS Model

Increased human activities in China's coastal zone have resulted in the depletion of ecological land resources.Thus,conducting current and future multi-scenario simulation research on land use and land cover change(LUCC)is crucial for guiding the healthy and sustainable development of coastal zones.System dynamic(SD)-future land use simulation(FLUS)model,a coupled simulation model,was developed to analyze land use dynamics in China's coastal zone.This model encompasses five scenarios,namely,SSP1-RCP2.6(A),SSP2-RCP4.5(B),SSP3-RCP4.5(C),SSP4-RCP4.5(D),and SSP5-RCP8.5(E).The SD model simulates land use demand on an annual basis up to the year 2100.Subsequently,the FLUS model determines the spatial distribution of land use for the near term(2035),medium term(2050),and long term(2100).Results reveal a slowing trend in land use changes in China's coastal zone from 2000–2020.Among these changes,the expansion rate of construction land was the highest and exhibited an annual decrease.By 2100,land use predictions exhibit high accuracy,and notable differences are observed in trends across scenarios.In summary,the expansion of production,living,and ecological spaces toward the sea remains prominent.Scenario A emphasizes reduced land resource dependence,benefiting ecological land protection.Scenario B witnesses an intensified expansion of artificial wetlands.Scenario C sees substantial land needs for living and production,while Scenario D shows coastal forest and grassland shrinkage.Lastly,in Scenario E,the conflict between humans and land intensifies.This study presents pertinent recommendations for the future development,utilization,and management of coastal areas in China.The research contributes valuable scientific support for informed,long-term strategic decision making within coastal 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.

Coupling within Fluvial Geomorphic Systems:Spatial and Temporal Implications

Coupling within fluvial systems relates to the connectivity between the various components of the system. It can be viewed at several scales from local scales of hillslopetochannel and reachtoreach coupling, to larger scales of zonal coupling between the major functional zones of the fluvial system, and to the scale of regional coupling. Coupling influences how the system responds to environmental change and how the effects of environmental change are propagated through the system. This paper provides a review, based largely on previously published work, of the coupling concept, and how the effective temporal scales vary with the spatial scale of coupling. Local scale coupling is considered through the hillslope to channel coupling in the Howgill Fells, northwest England, observed over a 30year monitoring period, together with examples from badlands in Spain, and reachtoreach coupling on the River Dane, northwest England. At the zonal scale the relative influence of climatic and baselevel change on coupling through dryregion alluvial fans is considered on fan systems in Spain, Nevada, and UAE/Oman. For large scale regional coupling, the response of the Tabernas basin, southeast Spain to tectonic uplift, is examined. The factors influencing coupling mechanisms vary with temporal and spatial scales. At the hillslopetochannel scale the significant factors are the magnitude and frequency characteristics of sediment generation and removal mechanisms within the context of progressive morphological change. Effective timescales range from the individual event to decadal timescales. At the zonal scale, that of alluvial fans, the significant factors are climatic change, and particularly in the appropriate morphological setting, baselevel change. Effective timescales are of the order of hundreds to thousands of years. At the regional scale, the response to tectonic uplift may take >100 ka to be transmitted through the drainage basin.

COUPLING PATTERNS OF AIR-SEA INTERACTION AT MIDDLE & LOWER LATITUDES AND THEIR INTERDECADAL OSCILLATION

Diagnostic studies have been done of the seasonal and interdecadal variations of the coupling patterns for the air-sea interactions in the northern pacific region.by using 500-hpa geotential hight field of the Northern Hemisphere and monthly mean SST field of northern Pacific Ocean(1951～1995) and with the aid of the Singular Value Decomposition(SVD) technique.The results show that:(1) The distribution patterns of SVD,which link with the E1 Nino(or La Nina) events,are important in the interaction between the atmosphere and ocean while the atmosphere,coupling with it ,varies like the PNA teleconnection does.The coupling of airsea interactions is the highest in the winter(January) ,specifically linking the E1 Nino event with the PNA pattern in the geopotential height field.Of the four seasons,summer has the poorest coupling when the 500-hPa geopotential height field corresponding to the La nina event displays patterns similar to the East Asian-Pacific one(PJ).The spring and autumn are both transitional and the coupling is less thght in the autumn than in the spring.(2) Significant changes have taken place around 1976 in the pattern of air-sea coupling,with the year's winter having intensified PNA pattern of 500-hPa winter geopotential height field,deepened Aleutian low that moves southeast and the summer following it having outstanding PJ pattern of 500-hPa geopotential height field,which is not so before 1976.

The Soil Moisture and Net Primary Production Affected by CO_2 and Climate Change Using a Coupled Model

In this paper, a coupled model was used to estimate the responses of soil moisture and net primary production of vegetation(NPP) to increasing atmospheric CO2 concentration and climate change. The analysis uses three experiments simulated by the second-generation Earth System Model(CanESM2) of the Canadian Centre for Climate Modelling and Analysis(CCCma), which are part of the phase 5 of the Coupled Model Intercomparison Project(CMIP5). The authors focus on the magnitude and evolution of responses in soil moisture and NPP using simulations modeled by CanESM, in which the individual effects of increasing CO2 concentration and climate change and their combined effect are separately accounted for. When considering only the single effect of climate change, the soil moisture and NPP have a linear trend of 0.03 kg m–2 yr–1 and –0.14 gC m–2 yr–2, respectively. However, such a reduction in the global NPP results from the decrease of NPP at lower latitudes and in the Southern Hemisphere, although increased NPP has been shown in high northern latitudes. The largest negative trend is located in the Amazon basin at –1.79 gC m–2 yr–2. For the individual effect of increasing CO2 concentration, both soil moisture and NPP show increases, with an elevated linear trend of 0.02 kg m–2 yr–1 and 0.84 gC m–2 yr–2, respectively. Most regions show an increasing NPP, except Alaska. For the combined effect of increasing atmospheric CO2 and climate change, the increased soil moisture and NPP exhibit a linear trend of 0.04 kg m–2 yr–1 and 0.83 gC m–2 yr–2 at a global scale. In the Amazon basin, the higher reduction in soil moisture is illustrated by the model, with a linear trend of –0.39 kg m–2 yr–1, for the combined effect. Such a change in soil moisture is caused by a weakened Walker circulation simulated by this coupled model, compared with the single effect of increasing CO2 concentration(experiment M2), and a consequence of the reduction in NPP is also shown in this area, with a linear trend of-0.16 gC m-2 yr-2.

9号道岔区铺设减振垫浮置板的行车安全性及舒适性研究

地铁道岔区在基本轨、尖轨处以及道岔钢轨接头处存在大量钢轨不连续地段,轮轨相互作用强烈,轨道系统振动明显,减振垫浮置板轨道作为一种高等减振措施已应用于地铁线路道岔区。为探究减振垫浮置板应用于9号道岔的适用性,并作为减振地段与普通无砟轨道的过渡段的可行性,以某地铁高架9号道岔为研究对象,建立桥上道岔三维有限元模型,仿真分析地铁B型车在120 km/h直向过岔和30 km/h侧向过岔的情况下,列车的行车安全性、舒适性以及轨下结构形变。对比在9号单开道岔区域设置的2种刚度过渡方式的优劣及其减振效果,较为系统地论证了在9号道岔区域铺设减振垫浮置板的可行性。研究结果表明:1)列车通过铺设减振垫浮置板的9号道岔区域时,浮置板位移极值出现在转辙区域和心轨区域,最大位移出现在尖轨位置,可增大尖轨处单板橡胶垫支承刚度,以保证轨道结构变形均匀;2)列车逆向侧向通过设置过渡段的减振垫浮置板道岔区时,2级过渡方式的车体最大垂向加速度、最大横向加速度、最大脱轨系数、最大轮重减载率、轨道刚度变化率以及减振效果等指标均优于1级过渡方式;3)在道岔区铺设减振垫浮置板,列车直向和侧向通过时的行车安全性和舒适性均能满足相关评价指标,且2级过渡方式更优。研究结果可为后续道岔区减振设计研究提供一定的理论参考。

基于SD-PLUS耦合模型的陕西省土地利用变化及碳储量多情景预测

[目的]为探讨不同土地利用方式对区域生态系统碳储量的影响。[方法]以陕西省为研究对象,利用SD-PLUS耦合模型,采用国际耦合模式比较计划第6阶段(CMIP6)提出的耦合共享社会经济路线和代表性浓度路线(SSP-RCP)情景,对2030年陕西省的土地利用变化进行预测,然后利用InVEST模型模拟未来不同情景下陕西省碳储量及其空间分布。[结果](1)对构建的SD模型进行历史检验,其误差<5%,PLUS模型模拟的2020年土地利用Kappa指数为0.86,模型精度和可靠性总体符合要求;(2)3种情景下,未来建设用地面积均增加,增长速率从低到高的情景分别为SSP126、SSP245、SSP585;在所有情景下,林地面积均增加,水域面积均保持稳定;草地面积在SSP126情景下有小幅度增加,其他情景下减少;耕地面积3种情景下均减少;(3)3种情景下,陕西省碳储量均减少,关中平原建设用地的扩张占用大量的耕地是造成陕西省碳储量下降的主要原因。[结论]在SSP126情景下,建设用地扩张所占用的生态用地面积最小,碳储量损失最少,该情景同时考虑社会经济发展及生态保护的需要,可为未来陕西省国土资源保护和高质量发展提供参考模式。

东北地区城镇化与资源环境承载力耦合关系的时空变化

理清城镇化与资源环境承载力耦合关系可为城市可持续发展转型提供决策参考。在分析2003—2019年东北地区城镇化与资源环境承载力时空格局的基础上,采用耦合协调度模型定量剖析了二者耦合关系的时空变化特征。结果显示:2003—2019年,东北地区综合城镇化水平提升了114.29%,总体呈现“东高西低”、辽中南城市群和哈长城市群核心城市引领全域发展的局面;资源环境承载力呈增加趋势,增幅36.09%,空间上聚集于哈大线周边区域;资源环境承载力水平与综合城镇化水平的耦合协调度总体上呈上升趋势,近年增幅有所下降,且辽西北、吉林南部和黑龙江西北部耦合协调度相对较低,核心城市和重要城市耦合协调度普遍较高。亟须提升核心城市对中小城镇的辐射引领能力,并加强生态退化地区的环境保护和高质量发展。

超声耦合TiO_(2)/UV光催化处理对玉米秸秆组分影响研究

本文采用超声耦合Ti O_(2)/UV光催化处理玉米秸秆,探究处理条件对玉米秸秆组分及结构的影响。研究结果表明,在Ti O_(2)投加量为0.25g·L^(-1)、pH值为8.25、超声强度为0.625W·m L^(-1)、处理1h的条件下,玉米秸秆中木质素和半纤维素含量分别由未处理前的26.06%、20.58%降低到22.85%、18.39%,纤维素含量由37.67%增加到40.39%。超声耦合Ti O_(2)/UV光催化处理可以破坏玉米秸秆的结构,玉米秸秆断裂破碎成细小碎片,表面粗糙有褶皱。本研究可为超声耦合Ti O_(2)/UV光催化技术在玉米秸秆预处理中的应用提供技术参考。

基于局部-全局特征耦合与边界引导的遥感图像建筑物变化检测

针对现有变化检测方法局部特征和全局特征难以兼顾、变化对象和背景之间分界模糊的问题,提出了一种基于局部-全局特征耦合与边界引导的遥感图像建筑物变化检测方法。该方法在编码阶段采用并行的卷积神经网络和Transformer分别提取遥感图像的局部特征与全局表示。在不同尺度下,使用局部-全局特征耦合模块融合局部特征和全局特征表示,以增强图像特征的表达能力。引入边界引导分支获取变化对象的先验边界信息,使其引导变化图突出建筑物的结构特征,促进边界精确定位。该方法在LEVIRCD和WHU数据集上进行实验验证,其F 1-score分别为91.25%和91.27%,IoU分别为83.90%和83.95%。实验结果表明,该方法在检测精度上有较大的提升,且具有良好的泛化能力。

基于极端气温的西红柿Arrhenius品质预测耦合模型构建

目的:基于Arrhenius方程结合气象温度数据构建西红柿品质预测耦合模型,预测西红柿在极端气温下短期贮运过程的品质变化。方法:分析2020年潍坊、保定、大兴气象温度数据,选取7个温度点模拟西红柿在短期贮运过程中极端温度的变化范围。基于Arrhenius方程,结合气温与失重率、硬度、色差(ΔE)和感官评分(SE)构建西红柿品质预测耦合模型,并选取-10,12℃进行验证。结果:贮运48 h内,西红柿的失重率和ΔE逐渐增加,SE和硬度逐渐降低。基于Arrhenius方程结合气象温度数据构建品质预测耦合模型,0~36℃贮藏条件下,失重率和SE变化采用零级反应拟合,硬度与ΔE变化分别采用一级反应与半级反应拟合;-15~0℃贮藏条件下,SE、ΔE、失重率与硬度的变化均采用零级反应拟合。对预测模型进行验证,12℃贮藏条件下西红柿的失重率、硬度与SE的相对误差在15%以内(除48 h的);-10℃贮藏条件下,西红柿的硬度与SE的相对误差在15%以内(除48 h的)。结论:基于Arrhenius方程结合极端气象温度数据构建的西红柿品质预测耦合模型能够有效预测极端温度条件下西红柿的品质。

火箭仪器舱结构模型的热振耦合模拟方法

传统的热振耦合方法缺乏对材料热特性变化的考虑,影响仿真分析的精度。为此,文章提出一种热特性参数与振动动态耦合的分析方法,建立动态变化的热振耦合方程,基于闪光瞬态法得到材料的热特性参数并将其应用在结构传热过程的数值仿真计算中。结果表明,是否考虑材料的热特性变化会对结构的传热过程仿真结果产生较大影响,并进一步影响结构的刚度特性仿真结果,从而造成结构模态分析偏差。采用本研究提出的动态变化的热振耦合模拟方法可提高传热仿真分析的精度和可靠度。

过去40 a来祁连山地区植被变化特征及其与气候的关系

在全球变暖背景下,祁连山植被生长状态发生了明显变化,研究祁连山植被与气候的关系对西北地区生态建设具有重要意义。基于1982—2022年GIMMS NDVI数据及ERA5气温和降水数据,分析祁连山地区NDVI的变化趋势及其与气候因子的相关性。结果表明,祁连山地区NDVI高值区主要集中在东段(0.6~0.8),并自东向西逐渐减小。过去40 a,祁连山地区NDVI整体呈增加趋势,主要由于生长季NDVI的显著增加,而在非生长季,祁连山中、东部部分地区NDVI呈减小趋势。祁连山地区NDVI的变化与气温、降水整体呈正相关关系,但生长季NDVI与降水在祁连山东部部分地区呈负相关,非生长季NDVI与气温在祁连山西部部分地区呈负相关。祁连山夏季NDVI与对应时段气温和降水之间存在显著耦合模态,气温和降水的增加整体上对NDVI增加有益,但祁连山东部地区生长季NDVI增加主要由气温升高所致。

黄河几字湾气溶胶对植被总初级生产力的影响

基于2006~2020年黄河几字湾多源遥感数据,利用标准化椭圆分析AOD-PAR-GPP的时空变化,随后通过结构方程模型和地理加权回归模型耦合构建GWR-SEM模型量化AOD对GPP的影响,并采用Sen趋势分析、MK显著性检验及灰色预测模型等方法探讨AOD与GPP未来变化趋势.结果表明:时间上,AOD、PAR和GPP呈协同上升趋势,其中AOD在2008、2020年到达最低值0.17和最高值0.46;GPP分别在2007年、2018年达到最低值266.4867.04gC/(m^(2)·a)和最高值408.87gC/(m^(2)·a),且三者季节差异明显,发现在植被生长季6月存在着GPP光饱和点.在空间上,AOD高值区主要分布在阿拉善盟;PAR分布与AOD相似,并与GPP呈负相关;GPP呈北低南高,其高值范围的扩大表现为延安贡献的增强.鄂尔多斯和榆林作为AOD主要污染源,在整体上由西向东逆时针扩散.GPP贡献地在榆林,具有西北向东南的变化趋势.锡林郭勒、大同及银川等地区GPP主要受AOD、PAR与降水的影响,包头、朔州及中卫等地区GPP受PAR和降水的影响;通过模型AOD对GPP产生的标准化总效应影响为0.758,且GPP变化主要受气温的影响,其次是AOD和PAR及降水,在各间接路径中PAR起关键作用.趋势预测上,几字湾北部的AOD和以榆林为代表的东南部GPP有进一步加快的趋势;2021~2030年AOD上升趋势相对缓慢,而GPP上升趋势较快.

城市内涝灾害对应急救援服务可达性的影响评估

【目的】城市化进程加快和气候变化导致内涝积水频发,造成道路封闭和交通堵塞,给城市应急救援响应的时效性带来严重影响。为了准确评估暴雨内涝下的城市应急救援响应能力,【方法】以荔湾区为例,通过构建内涝水动力模型,模拟不同设计降雨情景下的内涝积水,识别道路积水风险,明确阻断道路,并结合两步移动搜寻法(2SFCA)对不同脆弱性的兴趣点(POI)的应急救援服务可达性进行评估。【结果】结果显示:随着降雨重现期从1 a一遇增大到100 a一遇,内涝积水面积增大,平均积水深度从0.08 m增大到0.20 m。受积水影响道路数量持续增加,阻断道路长度从11 km上升至49 km,增长了超过300%。随着阻断道路的增多,应急救援可达的POI数量呈现下降趋势,并且在不同时间阈值内平均下降40%以上,可达性呈明显下降趋势。【结论】内涝模型耦合城市路网得到的道路积水可以揭示阻断道路的总体格局,可达性模型可以快速估算出应急救援的时效性。结果可为应急救援响应能力的评估提供参考。