Analysis of Short-term Cloud Feedback in East Asia Using Cloud Radiative Kernels

Cloud radiative kernels were built by BCC_RAD(Beijing Climate Center radiative transfer model)radiative transfer code.Then,short-term cloud feedback and its mechanisms in East Asia(0.5°S−60.5°N,69.5°−150.5°E)were analyzed quantitatively using the kernels combined with MODIS satellite data from July 2002 to June 2018.According to the surface and monsoon types,four subregions in East Asia-the Tibetan Plateau,northwest,temperate monsoon(TM),and subtropical monsoon(SM)—were selected.The average longwave,shortwave,and net cloud feedbacks in East Asia are−0.68±1.20,1.34±1.08,and 0.66±0.40 W m^−2 K^−1(±2σ),respectively,among which the net feedback is dominated by the positive shortwave feedback.Positive feedback in SM is the strongest of all subregions,mainly due to the contributions of nimbostratus and stratus.In East Asia,short-term feedback in spring is primarily caused by marine stratus in SM,in summer is primarily driven by deep convective cloud in TM,in autumn is mainly caused by land nimbostratus in SM,and in winter is mainly driven by land stratus in SM.Cloud feedback in East Asia is chiefly driven by decreases in mid-level and low cloud fraction owing to the changes in relative humidity,and a decrease in low cloud optical thickness due to the changes in cloud water content.

Evaluation of Cloud Feedback at Local Scale： Warming or Cooling？

Clouds affect the climate by positive and negative feedback. To study these effects at local scale, a radiation station was set up, which used two CM21 Kipp ＆ Zonen pyranometers （one inverted）, and two CG1 Kipp ＆ Zonen pyrgeometers （one inverted） in Logan, Utah, USA. The pyranometers and pyrgeometers were ventilated using four CV2 Kipp ＆ Zonen ventilation systems. Ventilation of pyranometers and pyrgeometers prevent dew, frost and snow accumulation, which otherwise would disturb the measurement. Knowing that available energy （Rn） as Rn = Rsi - Rso ＋ Rli - Rio where Rsi and Rso are downward and upward solar radiation, respectively, and Rli and Rio as atmospheric and terrestrial, respectively, the effects of cloudiness were evaluated on a daily and annual basis. The results indicate that for the partly cloudy days of 4 and 5 September, 2007, cloudiness caused less available energy （Rn） in the amounts of-1.83 MJ·m^-2·d^-1 and -3.83 MJ·m^-2·d^-1 on these days, respectively. As shown, due to cloudiness at the experimental site, the net radiation loss was 2,804 - 4,055 = -1,251 MJ·m^-2·d^-1, which indicates a negative feedback due to cloudiness.

Cloud Feedback on SST Variability in the Western Equatorial Pacific in GOALS/LASG Model

The cloud feedback on the SST variability in the western equatorial Pacific in GOALS/LASG model is studied in this paper. Two versions of the model, one with the diagnostic cloud and another with the prescribed cloud, are used. Both versions are integrated for 45 years. It is found that in the prescribed cloud run, the SST variability in the western equatorial Pacific is mainly of interdecadal time scale and the interannual variability is very weak. In the diagnostic cloud run, however, the interdecadal SST variability is depressed much and the interannual SST variability becomes much significant.The mechanism for the feedback is then explored. The variability of sea surface temperature (SST) in the western equatorial Pacific is found to be controlled mainly by the zonal wind anomaly, through the process of upwelling/downwelling in both versions. Then it is found that in the diagnostic cloud case, the negative feedback of the solar short wave (SW) flux acts significantly to balance the effect of upwelling/downwelling in addition to the latent flux. In addition, the variability of the SW flux is shown to be closely related to the variability of the middle and high cloud covers. Therefore, the negative feedback of the SW surface flux may have significant contribution to the cloud feedback on the SST variability.

Thermodynamic Feedback between Clouds and the Ocean Surface Mixed Layer

A cloud-ocean planetary boundary layer (OPBL) feedback mechanism is presented and tested in this paper. Water vapor, evaporated from the ocean surface or transported by the large-scale air flow, often forms convective clouds under a conditionally unstable lapse rate. The variable cloud cover and rainfall may have positive and negative feedback with the ocean mixed layer temperature and salinity structure. The coupling of the simplified Kuo's (1965) cumulus cloud model to the Kraus-Turner's (1967) ocean mixed layer model shows the existence of this feedback mechanism. The theory also predicts the generation of low frequency oscillation in the atmosphere and oceans.

Calculating the Climatology and Anomalies of Surface Cloud Radiative Effect Using Cloud Property Histograms and Cloud Radiative Kernels

Cloud radiative kernels(CRK)built with radiative transfer models have been widely used to analyze the cloud radiative effect on top of atmosphere(TOA)fluxes,and it is expected that the CRKs would also be useful in the analyses of surface radiative fluxes,which determines the regional surface temperature change and variability.In this study,CRKs at the surface and TOA were built using the Rapid Radiative Transfer Model(RRTM).Longwave cloud radiative effect(CRE)at the surface is primarily driven by cloud base properties,while TOA CRE is primarily decided by cloud top properties.For this reason,the standard version of surface CRK is a function of latitude,longitude,month,cloud optical thickness(τ)and cloud base pressure(CBP),and the TOA CRK is a function of latitude,longitude,month,τand cloud top pressure(CTP).Considering that the cloud property histograms provided by climate models are functions of CTP instead of CBP at present,the surface CRKs on CBP-τhistograms were converted to CTP-τfields using the statistical relationship between CTP,CBP andτobtained from collocated CloudSat and MODIS observations.For both climate model outputs and satellites observations,the climatology of surface CRE and cloud-induced surface radiative anomalies calculated with the surface CRKs and cloud property histograms are well correlated with those calculated from surface radiative fluxes.The cloud-induced surface radiative anomalies reproduced by surface CRKs and MODIS cloud property histograms are not affected by spurious trends that appear in Clouds and the Earth's Radiant Energy System(CERES)surface irradiances products.

基于云平台的反馈式健康教育在炎症性肠病居家患者中的应用效果研究

目的:研究基于云平台的反馈式健康教育对居家炎症性肠病患者的影响,以期拓展炎症性肠病患者的居家健康教育模式。方法:采用非同期对照的研究方法,便利选取青岛市某三级甲等医院于消化内科出院的炎症性肠病患者为研究对象,将2022年10月—12月收治的56例患者作为对照组,实施常规院外随访;2023年1月—3月收治的56例患者作为观察组,借助云平台为居家炎症性肠病患者提供反馈式健康教育,比较两组患者出院3个月后自我管理能力、知识水平、服药依从性、体质量指数、血清白蛋白、前白蛋白及观察组云平台阅读依从性。结果:对照组及观察组各退出2例,最终观察组及对照组各54例患者完成此项研究,干预前,两组患者的自我管理能力各维度、知识水平、服药依从性、体质量指数、血清白蛋白、前白蛋白得分/数值比较,差异均无统计学意义(P>0.05);干预3个月后,观察组自我管理能力各维度、知识水平、服药依从性、体质量指数均优于对照组,差异有统计学意义(P<0.05),观察组与对照组患者的知识水平、服药依从性均优于干预前,差异有统计学意义(P<0.001);干预3个月后,对照组与观察组血清白蛋白、前白蛋白比较,差异无统计学意义(P>0.05);观察组云平台总阅读量为3500次,阅读时长为(5.84±2.11)min。结论:基于云平台的反馈式健康教育模式可提高患者的自我管理能力,提高患者知识水平、服药依从性及体质指数,但对血清白蛋白、前白蛋白无影响。

Regime Behavior in the Sea Surface Temperature-Cloud Radiative Forcing Relationships over the Pacific Cold Tongue Region

Previous analyses on the estimates of water vapor and cloud-related feedbacks in the tropics usually use observations over the Earth Radiation Budget Experiment （ERBE） period （1985-89）. To examine the sample dependence of previous estimates, the authors extend the analysis to two additional periods： 1990-94 and 1995-99. The results confirm our hypothesis, i.e., the values of the feedbacks depend on the period of data coverage. The differences in the feedbacks from cloud radiative forcings （CRFs） estimated from the three periods are particularly significant. Two possible causes for these differences are proposed. First, a regime behavior in the CRFs-Sea Surface Temperature Anomaly （SSTA） rela- tionship over the cold tongue region is revealed： when SSTA is below -0.5℃, the CRF anomalies are insensitive to the SSTA; when the SSTA is between -0.5℃ and 2.0℃, the CRF anomalies are positively correlated with the SSTA; however, when the SSTA exceeds 2.0℃, the CRF anomalies decrease with the SSTA. This regime behavior is due to the regime behavior of cirrostratus and deep convective clouds. Second, the CRFs-SSTA relationship is regulated by remote forcings. Warming of the far eastern equatorial Pacific would reduce the water vapor convergence over the central Pacific by weakening the trade wind over the southeastern Pacific, thereby reducing the feeding of moisture to the convective flow. The results suggest that CRFs-SSTA relationships during ENSO events are nonlinear and strongly depend on the magnitude and the spatial distribution of the SSTA.

Dimethylsulfide and Coral Bleaching: Links to Solar Radiation, Low Level Cloud and the Regulation of Seawater Temperatures and Climate in the Great Barrier Reef

Coral reefs produce atmospheric dimethylsulfide (DMSa) which oxidises to non-sea-salt (nss) sulfate aerosols, precursors of cloud condensation nuclei (CCN) and low level cloud (LLC), reducing solar radiation and regulating sea surface temperatures (SSTs). Here we report measurements of solar radiation, SST, LLC, DMS flux, , and rainfall before, during and after a major coral bleaching event at Magnetic Island in the central Great Barrier Reef (GBR). Measurements are compared with those made at the nearby fringing reef of Or-pheus Island where coral bleaching did not occur. Extreme solar radiation levels occurred from November to late January and could have reflected cloud radiative effects that increased downwelling of solar radiation. High levels of LLC often coincided with high periodic fluxes of DMS from the unbleached coral reef at Orpheus Island (e.g. 14 - 20 μmol·m-2·d-1), in direct contrast to the very low fluxes of DMS that were emitted from the bleached, human-impacted Magnetic Island fringing reef (nd-0.8 μmol·m-2·d-1) when SSTs were >30°C. Continuous SSTs measurements at the Magnetic Island reef revealed various heating and cooling periods, interspersed with stable SSTs. Cooling periods (negative climate feedback) ranged from -1°C to -3°C (7 day mean -1.6°C), and often seemed to occur during low tides, periodic pulses of DMS flux and LLC, keeping SSTs °C. In contrast warming periods of +1°C to +3°C (positive climate feedback, 7 day mean +1.52°C), seemed to occur during increasing tides, decreasing DMS flux and low to medium levels of LLC which increased solar radiation and caused SSTs over 30°C and corals to bleach. Alternation between these two states or types of feedback is indicated in this research and may be a function of enhanced scattering of solar radiation from nss-sulfate aerosols that originate from oxidation of DMSa produced from the coral reefs in the GBR. The net radiative forcing from clouds can be as high as four times as large as the radiative forcing from a doubling of CO2 levels in the atmosphere, which needs to be taken into account when ascribing coral bleaching events in the GBR solely to GHG warming. Further studies are needed to more critically assess the importance of this GBR coral reef-cloud feedback to the climate of northern Australia and the western Pacific, where the greatest biomass of coral reefs occurs.

艰险山区铁路桥隧技术接口悬挂威胁等级评估

艰险山区环境条件极端恶劣、地质灾害频发,铁路沿线桥隧工程占比大,为提高桥隧工程技术接口管理水平,构建贝叶斯反馈修正云模型对桥隧技术接口悬挂威胁等级进行评估。首先,以铁路桥隧工程技术接口为基础,考虑不同参建方之间的接口共性问题和艰险山区铁路建设面临的一系列技术难题对接口悬挂的影响作用,从业主方因素、勘察设计方因素、承包方因素、与项目关联的其他因素、外界因素5个方面出发,构建了桥隧工程技术接口悬挂威胁等级评价指标体系,并利用IFAHP法进行赋权。然后,运用贝叶斯反馈修正原理构建了艰险山区铁路桥隧工程技术接口悬挂威胁等级评估模型。最后,以贡多顶隧道和奔中车站双线大桥桥隧工程技术接口为例,对其悬挂威胁等级进行评估,并借助MATLAB进行可视化分析。通过工程实例表明,该技术接口悬挂威胁综合等级为严重,其中勘察设计因素对桥隧技术接口的悬挂威胁程度最高。

基于贝叶斯反馈修正云模型的虚拟电厂运营风险综合评价方法

研究了虚拟电厂运营风险综合评价体系,为虚拟电厂建设运营提供支撑与指导。首先以运行风险、经济风险、安全风险和管理风险为一级指标构建了虚拟电厂风险综合评价指标库,为虚拟电厂安全可靠运行评价提供了支撑。其次提出了虚拟电厂风险综合评价模型,选用有序加权平均(ordered weighted average,OWA)—改进的层次分析法(analytic hierarchy process,AHP)对指标进行赋权,进而通过基于贝叶斯反馈修正的云模型评价方法得出各级指标的评价分数,用以评价虚拟电厂的风险程度,为虚拟电厂运行改进与优化提供判断依据。最后选取某虚拟电厂进行算例分析验证了所提基于贝叶斯改进云模型的虚拟电厂风险评价指标体系的有效性及优越性。

基于云班课平台的手机视频反馈法在健康评估实训教学中的应用

目的:探讨基于云班课平台的手机视频反馈法在健康评估实训教学中的应用,为提高课堂教学效果提供参考。方法:选取了2020级护理学生86例作为研究对象,对照组采用传统教学法,观察组采用基于云班课平台的手机视频反馈法,比较两组学生的学习成绩。结果:观察组学生的理论成绩、操作成绩高于对照组(P<0.05);观察组学生的学习效果优于对照组(P<0.05)。结论:对护理学生实施基于云班课平台的手机视频反馈法,能够提高学生的学习成绩。

大气CO_2浓度非均匀动态分布条件下的气候模拟

利用现有大气本底站的大气CO2浓度观测信息,综合考虑不同经济区划与土地覆盖类型对应的CO2浓度差异及其季节变化规律,构建模式区域内以月为单位的网格化大气CO2浓度非均匀动态分布数据模型.由此数据模型驱动RegCM4-CLM3.5区域气候模式运行,对东亚区2000年3月—2009年2月之间的气候变化特征进行了模拟,进而对大气CO2浓度非均匀动态分布可能引起的区域气候效应进行了初步研究.结果表明:目前气候模式中CO2浓度的常态均匀分布假设可能将温室效应夸大了10%左右.对大气CO2浓度非均匀动态分布影响气温变化的可能机制进行研究表明:CO2的自身效应(改变大气透射率)并不是导致Exp2试验温度降低的主要原因.大气CO2浓度的变化影响了大气与植物胞间CO2分压差,陆地植被通过改变气孔阻力适应这种变化,气孔阻力的变化直接影响到植物与大气间水分的交换,这种作用一方面通过蒸发冷却改变环境温度,另一方面,蒸发水分改变了近地面层湿度,进而水汽扩散到空中影响低云的分布.冬季,植物处于非生长季,对大气CO2浓度变化响应微弱,湿度和低云变化不明显;夏季,植物生长旺盛,由CO2生理学强迫激发的云反馈效应强烈,其效果是使中低云趋于增加,进而减弱了到达对流层低层的太阳短波辐射,造成温室效应减弱.

气候模式中云辐射反馈过程机理的评述

云对地气系统的辐射收支具有十分重要的作用,云辐射参数化是目前气候模式中不确定性的主要来源。云可以通过多种途径对辐射产生影响,形成不同符号、不同量值的反馈机制。研究表明,模式气候对不同的云辐射参数化方案十分敏感。预报云水含量方案的引入,改进了对云辐射过程的模拟,但与观测资料相比仍有差距。一般说来,模式中引入云水的相变和相互作用的云粒子大小产生负反馈,而光学厚度和云量产生的是正反馈。云辐射反馈的净作用其大小和符号因模式而异。云辐射与大尺度天气气候背景之间有着紧密的联系,尤其是海温对辐射平衡有显著影响。最后总结了当前云辐射研究中存在的主要问题,并提出了改进的途径。

耦合模式热带太平洋云—气候反馈模拟误差评估

云—气候反馈是热带海气相互作用的重要过程,同时也是气候模拟的难点。本文利用IPCCAR4提供的耦合模式20世纪模拟试验结果和观测资料,通过滤波和经验正交展开(EOF)的方法将热带太平洋海表温度的年际变化和年代际变化信号分别提取出来,然后再分别计算观测和模式在年际和年代际时间尺度上云—辐射和热通量反馈特征,发现在上述两个时间尺度上,耦合模式模拟的云—辐射和热通量的反馈都要比观测和再分析资料的偏弱。反馈偏弱的可能原因是模式中热带大气对流和云对海表温度变化的敏感性比真实大气要偏弱。值得注意的是,尽管耦合模式热带太平洋年代际热力反馈偏弱,但是耦合模式模拟的热带太平洋南北纬10°之间海表温度的年代际增温趋势与观测相当。进一步分析表明,只用年代际热力反馈来解释热带太平洋的气候变化是不够的,还必须考虑动力反馈对于海表温度变化的调节作用。

地球失控增暖可能性的数值模拟

通过改变太阳常数引进强外辐射强迫的变化,利用NCAR气候系统模式CSM1.4,就气候系统对强外辐射强迫下的失控增暖效应进行了初步研究。结果表明:气候对于太阳常数分别增加2.5%、10%与增加25%的响应有所不同,即对于较小的强迫,气候系统的响应是线性的;而对于较大的强迫,响应很可能是非线性的。对于NCAR模式,如果强迫足够大,气候系统将会经历失控增暖。失控增暖的主要趋势并不是最初设想的正的水汽反馈增暖,至少在模式中,不只是“失控的温室效应”增暖,还有“失控的云反馈”增暖。

基于前馈和反馈控制运行时虚拟资源动态分配

随着云计算的流行和发展,越来越多的应用系统被部署在云服务器上,以可伸缩的方式按需获取虚拟资源并按使用量付费.因此,如何在保证应用系统优化运行的同时以一种考虑成本效益的方式来分配和使用虚拟资源就成了一个重要的研究问题.传统的手工调整方法不但会增加系统管理员的负担,而且准确性较差并有一定的延迟.现有的虚拟资源动态分配方法大多是在发现系统运行时质量问题后进行资源动态调整的,因此具有一定的延迟性,而且还忽略了虚拟资源的异构性带来的影响.针对这些问题,提出了一种基于控制理论的虚拟资源动态分配方法.该方法使用一个前馈控制器来动态调整虚拟资源的数量,同时使用一个反馈控制器来动态调节各个虚拟资源处理的负载比例,从而实现应用系统的优化运行和虚拟资源的有效利用.与静态虚拟资源分配方法以及仅包括前馈控制方法的对比实验表明,所提出的方法能够在保证应用系统优化运行的同时提高虚拟资源利用的有效性.

基于变粒度仿反馈机制的回转窑烧成状态智能认知方法

采用改进的压缩Gabor滤波器组对火焰图像进行预处理,由比例不变特征变换描述符、视觉单词本和潜在语义分析结合的方法提取火焰图像感兴趣区域局部形态特征.在给定的认知信息粒度层次中基于特征分辨度、认知粒度熵和特征权值的定义,构建相应的简约特征空间.生成多类训练样本的多维逆向正态粒子云模型,并基于云隶属度构造模式分类器获取回转窑烧成状态分类规则.基于认知误差的定义,给出基于变粒度仿反馈机制的回转窑烧成状态智能认知方法.实验表明,文中方法对回转窑烧成状态认知效果较优.

基于负反馈的云设计资源调度机制与算法

为了在海量设计资源中快速高效地将合适的设计资源推送给所需的设计人员,以缩短产品研发周期,提出面向产品设计的云设计资源建模方法,在云设计资源响应能力模型和设计人员需求与偏好模型的基础上,构建了基于负反馈的云设计资源调度机制,通过对该调度机制的求解实现了云设计资源响应能力与设计人员需求的相似度匹配,并将匹配度较高的云设计资源节点反馈给设计人员,提高了资源利用率。仿真及结果分析表明,该调度机制与算法能够最大限度地满足设计人员的需求,提高设计资源的利用率。

基于用户行为反馈的云资源调度机制

云计算中不断增长的资源种类、数量以及不断变化的用户需求给资源调度带来了极大的挑战,其中之一就是如何在复杂纷纭的云计算环境中为用户寻找真实所需的资源。针对这一问题,从用户的角度着手,基于用户行为对云资源调度问题进行深入的研究,提出了基于用户行为反馈的资源调度机制(user behavior-based resource scheduling mechanism with feedback control,UBRSM-FC)。UBRSM-FC利用用户交互行为,将用户行为信息融入到资源调度过程中,并结合相关反馈机制,建立用户需求的主动发现网络和反馈网络对调度过程不断微调和优化,使资源调度的结果与用户的主观感知更加接近。实验结果表明,UBRSM-FC通过反馈控制能够更好地满足不同用户不同程度的资源请求,提高了用户满意度,而且能够兼顾系统资源的利用率。

基于贝叶斯反馈云模型的空中目标威胁评估

在现代战争中,空袭与防空作战仍将是主要作战方式之一。对防空方而言,及早发现空袭目标、准确判断空袭意图,是合理分配火力、最大限度发挥自身抗击能力的基本前提。综合考虑了攻防双方及作战环境等因素的影响,建立空中目标威胁评估指标体系。采用云模型理论较好地处理了空袭的模糊性和随机性,通过贝叶斯反馈对专家主观认识差异进行修正,使专家意见更加统一,使威胁评估结果更为简洁合理,便于指挥员快速准确作出决策。