Variations in Surface Urban Heat Island and Urban Cool Island Intensity:A Review Across Major Climate Zones

The climate has an impact on the urban thermal environment,and the magnitude of the surface urban heat island(SUHI)and urban cool island(UCI)vary across the world’s climatic zones.This literature review investigated:1)the variations in the SUHI and UCI intensity under different climatic backgrounds,and 2)the effect of vegetation types,landscape composition,urban configuration,and water bodies on the SUHI.The SUHI had a higher intensity in tropical(Af(tropical rainy climate,Köppen climate classification),Am(tropical monsoon climate),subtropical(Cfa,subtropical humid climate),and humid continental(Dwa,semi-humid and semi-arid monsoon climate)climate zones.The magnitude of the UCI was low compared to the SUHI across the climate zones.The cool and dry Mediterranean(Cfb,temperate marine climate;Csb,temperate mediterranean climate;Cfa)and tropical climate(Af)areas had a higher cooling intensity.For cities with a desert climate(BWh,tropical desert climate),a reverse pattern was found.The difference in the SUHI in the night-time was greater than in the daytime for most cities across the climate zones.The extent of green space cooling was related to city size,the adjacent impervious surface,and the local climate.Additionally,the composition of urban landscape elements was more significant than their configuration for sustaining the urban thermal environment.Finally,we identified future research gaps for possible solutions in the context of sustainable urbanization in different climate zones.

Oxidative heat release intensity in coal at low temperatures measured by the hot-wire method

Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.

The shortest period of coal spontaneous combustion on the basis of oxidative heat release intensity

It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on the basis of the oxidative heat release intensity and thermal capacity at different temperatures.According to the basic parameters of spontaneous combustion,heat of water evaporation and gas desorption,the SSCPs of different coals are further predicted.Finally,this study analyzed the relationships of the SSCP and the judging indexes of the self-ignite tendency.The result shows that the SSCP non-linearly increases with the decrease of dynamic oxygen adsorption and increase of activation energy.Compared with the practical fire situation of mine,this reliable method can meet the actual requirement of mine production.

Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics

We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heatedwith an intense pulse of heavy ions.In this way,we determine the samples’heating dynamics and their microscopic and macroscopic structuralintegrity over a timespan of several microseconds.Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functionaltheory molecular dynamics simulations allows the inference of average temperatures around 1300 K,in agreement with predictions fromstopping power calculations.The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material,butdo indicate the onset of fracture in the diamond sample.Our experiments pave the way for future studies at the Facility for Antiproton andIon Research,where a substantially increased intensity of the heavy ion beam will be available.

Gastrointestinal manifestations of critical ill heatstroke patients and their associations with outcomes:A multicentre,retrospective,observational study

BACKGROUND Extreme heat exposure is a growing health problem,and the effects of heat on the gastrointestinal(GI)tract is unknown.This study aimed to assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes.AIM To assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes.METHODS Patients admitted to the intensive care unit(ICU)due to heatstroke were included from 83 centres.Patient history,laboratory results,and clinically relevant outcomes were recorded at ICU admission and daily until up to day 15,ICU discharge,or death.GI symptoms,including nausea/vomiting,diarrhoea,flatulence,and bloody stools,were recorded.The characteristics of patients with heatstroke concomitant with GI symptoms were described.Multivariable regression analyses were performed to determine significant predictors of GI symptoms.RESULTS A total of 713 patients were included in the final analysis,of whom 132(18.5%)patients had at least one GI symptom during their ICU stay,while 26(3.6%)suffered from more than one symptom.Patients with GI symptoms had a significantly higher ICU stay compared with those without.The mortality of patients who had two or more GI symptoms simultaneously was significantly higher than that in those with one GI symptom.Multivariable logistic regression analysis revealed that older patients with a lower GCS score on admission were more likely to experience GI symptoms.CONCLUSION The GI manifestations of heatstroke are common and appear to impact clinically relevant hospitalization outcomes.

INTERANNUAL VARIABILITY OF HEAT CONTENT, AND ITS RELATIONSHIP WITH THE SUMMER MONSOON INTENSITY, IN THE SOUTH CHINA SEA

This study analyzes the Ishii 700 m heat content(HC) in the South China Sea(SCS).During the 1978-2012 period,the HC in the SCS changed dramatically on interannual timescales.Three main findings emerged from the analysis.1)The first spatial pattern of the empirical orthogonal function(EOF1)was consistently distributed over most of the SCS,whereas that of the second empirical orthogonal function(EOF2) showed a dipole signal.2)The HC anomalies in the SCS were closely related to the SCS summer monsoon intensity.When the HC over most of the SCS increased(decreased) in previous winter,the SCS summer monsoon was strengthened(weakened).Therefore,the HC behavior in the SCS during previous winter can well predict the intensity of the SCS summer monsoon.3)HC anomalies in the SCS largely influence the monsoon and Walker circulations,in turn affecting the western Pacific subtropical high and finally the SCS summer monsoon.

Impact of the Urban Heat Island Effect on Ozone Pollution in Chengdu City,China

With the advancement of urbanization,the urban heat island effect and ozone pollution have become hot issues in urban research.The urban heat island effect can impact ozone conversion,but its mechanism of action is unclear.In this study,the effects of the urban heat island effect on ozone concentration in Chengdu City,China,were investigated by comparing the ozone concentration under different heat island levels with ozone data from March 2020 to February 2021 and the temperature and wind field data of ERA5-Land during the same period.The results showed that:1)regarding the distribution characteristics,the ozone concentration in Chengdu presented a‘high in summer and low in winter’distribution.The ozone concentration in summer(189.54µg/m^(3))was nearly twice that in winter(91.99µg/m^(3)),and the ozone diurnal variation presented a‘single peak and single valley’distribution,with a peak at 16:00.2)For the characteristics of the heat island effect,the heat island intensity in Chengdu was obviously higher in spring than in other seasons,and the diurnal variation showed a‘single peak and single valley’distribution,with the peak and trough values appearing at 9:00 and 17:00,respectively.Spatially,the eastern part of Chengdu was a heat island,while the western and northwestern parts were mostly cold island.3)The correlation analysis between heat island intensity and ozone concentration showed a significant positive correlation but with a 7–8 h time lag.Ambient air temperature was not the main factor affecting ozone concentration.The heat island effect impacts the ozone concentration in two ways:changing the local heat budget to promote ozone generation and forming local urban wind,which promotes ozone diffusion or accumulation and forms different areas of low and high ozone values.

Potential enstrophical diagnostic analyses on the mechanism of change of tropical cyclone intensity

It is indicated that the change of mean potential enstrophy within tropical cyclone (TC) corresponds tothe change of TC intensity. A series of factors influencing the intensity change have been discussed by calculating budget of potential enstrophy in tangential wave-number domain in cylindric coordinates. The results indicate thatthe vertical distribution of mean diabatic heating is an important factor that influences the change of TC intensitythrough transformation mechanism of the Coriolis effect and cyclonic vorticity, especially in the sudden intensifyingstage of TC. It is favourable to the intensification when the diabatic heating is largest in upper-middle troposphere,while TC weakens when this kind of role of heating become small or the heating is largest in lower troposphere. Therole of the axisymmetric fields of TC is different from that of the non-axisymmetric fields. In addition,we have analysed some other factors that influence TC intensity.

Impact of Dynamic and Thermal Forcing on the Intensity Evolution of the Vortices over the Tibetan Plateau in Boreal Summer

The Tibetan Plateau Vortex(TPV)is one of the main weather systems causing heavy rainfall over the Tibetan Plateau in boreal summer.Based on the second Modern-Era Retrospective Analysis for Research and Applications(MERRA-2)reanalysis datasets provided by the National Aeronautics and Space Administration(NASA),8 cases of TPV over the Tibetan Plateau generated in June-August with a lifetime of 42 hours are composited and analyzed to reveal the impact of dynamic and thermal forcing on the intensity evolution of TPVs.The results are as follows.(1)The TPVs appear obviously at 500 h Pa and the TPVs intensity(TPVI)shows an obvious diurnal variation with the strongest at 00 LT and the weakest at 12 LT(LT=UTC+6 h).(2)A strong South Asia High at 200 h Pa as well as a shrunken Western Pacific Subtropical High at 500 h Pa provide favorable conditions for the TPVI increasing.(3)The vorticity budget reveals that the divergence is indicative of the variation of the TPVI.The TPVI decreases when the convergence center at500 h Pa and the divergence center at 200 h Pa lie in the east of the TPVs center and increases when both centers coincide with the TPVs center.(4)Potential vorticity(PV)increases with the enhancement of the TPVI.The PV budget shows that the variation of the TPVI is closely related to the diabatic heating over the Tibetan Plateau.The increased sensible heating and radiative heating in the boundary layer intensify the ascent and latent heating release.When the diabatic heating center rises to 400 h Pa,it facilitates the development of the TPVs.

Altitude and intensity characteristics of parametric instability excited by an HF pump wave near the fifth electron harmonic

An ionospheric heating experiment involving an O mode pump wave was carried out at European Incoherent Scatter Scientific Association site in Troms？. The observation of the ultra high frequency radar illustrates the systematic variations of the enhanced ion line and plasma line in altitude and intensity as a function of the pump frequency. The analysis shows that those altitude variations are due to the thermal effect, and the intensity variations of the enhanced ion line are dependent on whether or not the enhanced ion acoustic wave satisfy the Bragg condition of radar. Moreover, a prediction that if the enhancement in electron temperature is suppressed,those systematic variations will be absent, is given.

土地利用类型变化对城市热岛效应的影响分析

首先基于北京市2013—2020年Landsat-8卫星遥感影像,使用TIRS10_SC算法反演北京市地表温度;其次,对温度反演结果进行归一化处理,进行热岛等级划分,并计算热岛强度指数;最后,结合土地利用类型数据,分析土地利用类型覆盖面积变化对城市热岛强度的影响。结果表明:1)2013—2020年北京市的城市热岛效应呈现出先上升后下降的趋势,2015年城市热岛效应现象最明显;2)2013—2020年裸土地变化程度最大,其中有40.060%的裸土转变为植被,24.988%的裸土转变为建设用地;3)出现次热岛和强热岛现象的区域地表覆盖类型主要是建设用地和裸土,出现绿岛和冷岛的区域地表覆盖类型主要是植被和水体,并且在相同面积占比情况下,水体缓解热岛效应的效果更加明显。

武汉市建设用地开发强度与热岛强度特征研究

随着城市化进程的加快,越来越多的人口从农村进入城市,城市的气候和环境问题日益凸显。城市化过程导致城市下垫面改变,自然土体被不透水的钢筋混凝土覆盖,城市热岛问题突出。文章通过研究武汉市各类建设用地的开发强度特征,包括容积率、建筑密度和建筑平均高度,计算武汉市地表温度和热岛强度,分析和总结武汉市各类建设用地开发强度和热岛效应特征,从空间形态出发提出规划改善策略,为城市规划和建设提供指导依据。

超声龈下刮治联合黄连解毒汤加味含漱治疗慢性牙周炎临床研究

目的:观察超声龈下刮治联合黄连解毒汤加味含漱治疗慢性牙周炎热毒炽盛证的临床疗效。方法:选取104例慢性牙周炎热毒炽盛证患者,按随机数字表法分成对照组和观察组各52例。对照组剔除2例,最终纳入研究观察组52例、对照组50例。2组均进行龈上洁治、抛光,7 d后进行超声龈下刮治。对照组给予0.9%氯化钠溶液含漱,观察组给予黄连解毒汤加味含漱。比较2组临床疗效、牙周指数[牙周探诊深度(PD)、牙龈指数(GI)、牙龈出血指数(BI)、菌斑指数(PLI)]、龈沟液中炎症因子[白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)]水平及龈沟液中氧化应激指标[丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、一氧化氮(NO)]水平。结果:治疗1个月后,观察组临床疗效总有效率98.08%,高于对照组84.00%(P<0.05)。2组PD、GI、BI、PLI均较治疗前降低(P<0.05),观察组上述4项牙周指数均低于对照组(P<0.05)。2组龈沟液中IL-1β、TNF-α水平均较治疗前降低(P<0.05),观察组龈沟液中IL-1β、TNF-α水平均低于对照组(P<0.05)。2组龈沟液中MDA、NO水平均较治疗前降低(P<0.05),龈沟液中SOD、GSH-Px水平均较治疗前升高(P<0.05);观察组龈沟液中MDA、NO水平均低于对照组(P<0.05),龈沟液中SOD、GSH-Px水平均高于对照组(P<0.05)。结论:超声龈下刮治联合黄连解毒汤加味含漱治疗慢性牙周炎热毒炽盛证,可有效改善牙周症状,作用机制可能与抑制牙周组织炎症及改善牙周组织氧化应激反应有关。

水平内螺纹管中超临界RP-3航空煤油换热数值研究

针对航空换热器的应用,对水平内螺纹管中RP-3航空煤油的超临界换热进行了数值研究,着重考察煤油压力和螺纹升角对换热的影响。基于管截面温度、密度、局部质量流速、流线分布状况,揭示周向非均匀传热恶化的机理。通过类气膜温度梯度和旋流动能的演变以定量表征类气膜程度和旋流强度。提出了适用于周向四个位置努塞尔数预测的换热关联式。结果表明:流动性差的类气膜在冷流体和热壁面之间形成阻隔,导致传热恶化问题。浮升力作用致使流场和温度场出现畸变,类气膜厚度周向不均,产生局部超厚类气膜,对应的传热恶化加剧。厚类气膜区和二次流涡在浮升力和螺纹旋流耦合机制下沿流动方向不断逆时针改变位置。提高煤油压力有利于削弱和延后类气膜效应,且使旋流强度下降。随着螺纹升角增大,类气膜效应略有削弱和后延,旋流强度显著提高。换热关联式预测偏差普遍位于±10%的误差范围。

Heat transfer model for microwave hot in-place recycling of asphalt pavements

In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of unsteady heat conduction. Four onedimensional heat transfer models are established for the asphalt mixtures outside the heating range, which are simplified into four half-infinite solids. The intensity of the radiation electric field is calculated through experiment by using heating water loads. It is suggested that the mathematical model of boundary conditions can be established in two ways, which are theoretical deduction and experimental reverse. The actual temperature field is achieved by fitting temperatures of different positions collected in the heating experiment. The simulant temperature field, which is solved with the Matlab PDE toolbox, is in good agreement with the actual temperature field. The results indicate that the proposed models have high precision and can be directly used to calculate the temperature distribution of asphalt pavements.

品管圈活动在降低重症监护室加热湿化器非故障性报警发生率中的应用探讨

目的:探讨品管圈活动对降低重症监护室加热湿化器非故障性报警发生率的效果。方法:首先,成立品管圈小组,选定降低重症监护室加热湿化器非故障性报警发生率为活动主题,调查2021年12月1—15日期间重症监护室中加热湿化器的使用现状并设定改善目标。其次,绘制柏拉图、鱼骨图分析发生非故障性报警的原因。最后,根据PDCA原则制订相应对策并实施。比较品管圈活动实施前后加热湿化器非故障性报警的发生率及圈员的综合能力。结果:品管圈活动实施后,加热湿化器非故障性报警发生率由48.57%下降至8.23%,目标达成率为119.7%,进步率为83.06%,圈员的综合能力均有一定程度提升。结论:品管圈活动能有效降低重症监护室加热湿化器非故障性报警的发生率,在医学装备规范化管理上具有可推广应用的价值。

不同算法下超大城市中心城区夏季冠层热岛强度的时空分异特征

为准确评估高度复杂的超大型城市冠层热岛强度分异特征,以武汉市为例,提出一种考虑城市不同片区空间差异性的冠层城市热岛强度(canopyurbanheatislandintensity,CUHII)计算方法,并结合基于“城-郊”二分法的传统算法探讨不同算法下冠层城市热岛特征。结果显示:传统算法下各片区始终表现出城市热岛现象,且CUHII日变化曲线高度一致;与之相反,片区算法中各片区的CUHII日变化差异显著,具有多个大型生态空间的武昌片区在昼间出现了持续的冷岛现象。同时,除晴朗天气外,高温和降水天气会进一步加剧片区算法中城市片区间CUHII差异。此外,传统算法识别的冷、热岛中心范围较小并分布于中心城区外围,而片区算法识别的热岛中心呈带状覆盖城区中部高密集开发区,冷岛中心则邻近武昌片区内大型自然湖泊。结果表明,提出的算法弱化了城市区域发展不均对冠层热岛评估带来的干扰,有利于深入挖掘热岛特征并更加准确地识别城市热环境需要优先干预的区域。

温室传热水道与土壤换热强度影响的数值分析

以呼和浩特市某日光温室铺设的传热水道为研究对象,为提供传热水道在土壤中铺设间距、深度的准确依据,利用CFD数值模拟技术对传热水道在不同供水温度(30、40、50℃)、不同埋管深度(30、40、50cm)、不同管道间距(20、40、50cm)的情况时对温室土壤的换热强度进行研究与分析。结果表明:埋管深度越深对土壤地面温度影响越小,管道间距越宽则土壤的温度分布越分散,使土壤不容易达到温度扩散的饱和值,管温越高对管道以下的土壤影响越大,造成资源浪费;当埋管深度为30cm、管间距为20cm时,土壤的换热效果最佳。研究结果可为温室传热水道对土壤加热提供理论参考。

潜热对江淮地区一次强降水过程的影响

利用地面加密观测和ERA5再分析资料,采用潜热和垂直运动诊断技术,分析江淮地区2020年7月一次强降水维持时间长、小时雨强及累计雨量大的区域性强降水过程,研究其维持机制。结果表明:强降水按影响系统可分为2个阶段,第一阶段受第一个低涡和暖式切变线影响,第二阶段受第二个低涡和冷式切变线影响,强降水均发生在低涡和切变线南部的低空急流中,为暖区强降水。两阶段强降水的维持机制存在异同点,相同点:在天气尺度系统上升运动中潜热的正反馈作用,加强了上升运动和低空急流;在“急流自激机制”作用下,导致边界层上升运动的发展,提供对流发展的动力条件;不同点:边界层上升运动与天气尺度上升运动在第一阶段有一定的距离,第二阶段二者的位置几乎一致,形成边界层到对流层中上层的深厚上升运动区,维持深对流发展。

一个考虑人为热的日最大热岛强度诊断方程的适用性检验

城市热岛(Urban Heat Island,UHI)对热舒适、能源和生态安全有重要影响。准确预测日最大城市热岛强度(Maximum Urban Heat Island Intensity,UHIImax)可以预警能源消耗和保障室外热安全。基于局地气候分区(Local Climate Zone,LCZ)框架,在广州选择多个LCZ分区,并进行长达3年的局地气候观测。基于实测结果验证一个欧洲学者提出的未考虑人为热的日UHIImax诊断方程的适用性;进一步检验考虑人为热后扩展方程在广州的适用性。结果表明,该原始方程诊断结果与观测结果的相关系数为0.63,均方根误差(Root Mean Square Error,RMSE)为1.50 K,平均绝对误差(Median Absolute Error,MEAE)为0.97 K,d=0.60,诊断精度可适用。考虑人为热的扩展方程比原始方程诊断结果更加准确,RMSE降低了0.12 K,MEAE降低了0.10 K,d增加了0.04。方程在不同的LCZ的检验结果存在差异表明应针对不同的LCZ特征对方程进行修正,但增加人为热可提升在各LCZ的诊断表现。综上,该修正方程可以作为预测局地UHI发展的工具,提高湿热地区局地UHI的诊断精度。