Multi-Year Simulations and Experimental Seasonal Predictions for Rainy Seasons in China by Using a Nested Regional Climate Model (RegCM_NCC) Part Ⅱ:The Experimental Seasonal Prediction

A nested regional climate model has been experimentally used in the seasonal prediction at the China National Climate Center （NCC） since 2001. The NCC/IAP （Institute of Atmospheric Physics） T63 coupled GCM （CGCM） provides the boundary and initial conditions for driving the regional climate model （RegCM_NCC）. The latter has a 60-km horizontal resolution and improved physical parameterization schemes including the mass flux cumulus parameterization scheme, the turbulent kinetic energy closure scheme （TKE） and an improved land process model （LPM）. The large-scale terrain features such as the Tibetan Plateau are included in the larger domain to produce the topographic forcing on the rain-producing systems. A sensitivity study of the East Asian climate with regard to the above physical processes has been presented in the first part of the present paper. This is the second part, as a continuation of Part Ⅰ. In order to verify the performance of the nested regional climate model, a ten-year simulation driven by NCEP reanalysis datasets has been made to explore the performance of the East Asian climate simulation and to identify the model＇s systematic errors. At the same time, comparative simulation experiments for 5 years between the RegCM2 and RegCM_NCC have been done to further understand their differences in simulation performance. Also, a ten-year hindcast （1991-2000） for summer （June-August）, the rainy season in China, has been undertaken. The preliminary results have shown that the RegCM_NCC is capable of predicting the major seasonal rain belts. The best predicted regions with high anomaly correlation coefficient （ACC） are located in the eastern part of West China, in Northeast China and in North China, where the CGCM has maximum prediction skill as well. This fact may reflect the importance of the largescale forcing. One significant improvement of the prediction derived from RegCM_NCC is the increase of ACC in the Yangtze River valley where the CGCM has a very low, even a negative, ACC. The reason behind this improvement is likely to be related to the more realistic representation of the large-scale terrain features of the Tibetan Plateau. Presumably, many rain-producing systems may be generated over or near the Tibetan Plateau and may then move eastward along the Yangtze River basin steered by upper-level westerly airflow, thus leading to enhancement of rainfalls in the mid and lower basins of the Yangtze River. The real-time experimental predictions for summer in 2001, 2002, 2003 and 2004 by using this nested RegCM-NCC were made. The results are basically reasonable compared with the observations.

Review of recent studies of the climatic effects of urbanization in China

This paper summarizes recent studies on the effects of urbanization on climate in China. The effects of urbanization on local climate trends have been re-estimated based on homogenized observations and using improved methods. In this respect, the effect of urbanization on the observed warming trend of local surface air temperatures during the last few decades is determined as being about 20% at urban stations such as the Beijing Observatory. The large-scale weakening trend of wind speed is also about 20% more prominent at the city center than its surroundings. The effect of urbanization on precipitation is not profound, but results of high-resolution regional climate modeling suggest that this effect may depend on the urban extent. Although the urban heat island(UHI) should favor local atmospheric convection and hence precipitation, the increasingly extending urban land-use may reduce precipitation over the urban cluster in North China. It is found that urbanization can play a more notable role in extreme events than usual weather. High-resolution simulations show a positive feedback between the UHI and the super-heat wave in Shanghai during Julye August 2013. Relevant studies dealing with urban climate adaptation are discussed in relation to recent ?ndings.

Clean-energy utilization technology in the transformation of existing urban residences in China

Clean-energy substitution technology for existing residential buildings in cities is an inevitable choice for sustainable development and low-carbon ecological city construction.In this paper,the current status of energy-saving renovation and renewable-energy applications for existing residential buildings in various cities in China was summarized by using statistical methods.The geographical distribution of clean-energy power generation in primary energy production in China was explored in depth.According to different climatic divisions for existing urban residences,clean-energy production and consumption were analyzed and predicted based on the STIRPAT model.The results show that the energy consumption of urban residential buildings in 2016 increased by 43.6%compared with 2009,and the percentage of clean energy also increased from 7.9%to 13.4%.Different climatic regions have different advantages regarding clean energy:nuclear power generation leads in the region that experiences hot summers and warm winters,whereas wind and solar power generation lead in the cold and severely cold regions.The present results provide basic data support for the planning and implementation of clean-energy upgrading and transformation systems in existing urban residences in China.

珠三角地区近20年城镇化与景观生态安全耦合协调分析

针对城镇化进程加快导致的珠三角地区生态景观胁迫程度日趋严峻,亟需加强区域生态保护的现状,构建新型城镇化与景观生态安全的耦合协调模型,定量测度2000—2020年珠三角地区城镇空间扩展与景观生态安全耦合协调时空格局以及发展状态,运用多元回归分析和灰色预测模型揭示其驱动机理,并预测2040年城镇空间扩展和景观生态安全耦合的发展趋势。结果表明:珠三角地区9市城镇化与景观生态安全的耦合协调度在20年间呈现缓慢波动上升的趋势,耦合协调度由2000年的0.305~0.436升至2020年的0.385~0.545,现处于拮抗耦合阶段,未来20年将继续向着协调同步、有序发展的方向前进。珠三角地区经济发展不平衡,城镇开发建设和生态环境保护难以同步发展,景观生态状况不乐观,生态环境滞后型的地市逐渐增多,尚未全面形成良好的协调发展状态。对外开放程度、经济发展水平、科技投入水平等因素对耦合协调度的影响较为显著(P<0.05),今后对于区域可持续发展需要加强耦合协调的机理研究,持续关注城镇空间拓展与景观生态安全的协调发展趋势及特征。

宜居城市环境品质提升关键问题与研究路径

我国城市已迈入以品质提升为主的转型发展新阶段,宜居环境建设成为城市发展的新理念、新目标。本文介绍了“城市可度量、居民能感知、方法更本土、技术高融合”的城市环境品质提升策略与路线,重点阐述了“宜居城市环境品质评价和提升的本土化理论方法”“城市道路慢行系统与空间环境的适应性改造”“城市声、光、热环境品质的协同提升”与“城市宜居环境综合品质预测模型及应用”四大关键问题,以期构筑“新标尺”,支撑对城市环境品质的精确测度与科学提升。此外,本研究还就数智技术驱动下城市环境品质提升模式的创新与变革进行了探讨。

热感觉对气候温和地区热舒适模型的修正作用研究

为探究气候温和地区高校教室内的热舒适性,且修正预测热感觉和不满意度模型(predicted mean vote-predicted percentage of dissatisfaction,PMV-PPD模型)与实际热感觉投票值存在偏差情况,本文以昆明某高校大学生受试者为试验对象,分别测试室内环境参数、人员评估环境温度(t_(1))以及受试者主观评价等,共获得2229份有效数据。结果表明:在自然通风教室中,超过80%的大学生可以接受当前的热湿环境,PMV与实际平均热感觉投票(mean thermal sensation,MTS)模型相关较弱,PMV模型高估了受试者的实际热感觉,实测人员不满意百分比普遍大于预测不满意百分比。鉴于PMV模型预测准确性较低,综合考虑温度变化、主观反应等影响因素,提出人员评估环境温度(t_(1))作为修正性指标。人员评估环境温度与实际环境温度存在较强相关性,且在不同场景中两者温差值小于1.5℃。将t_(1)与热感觉投票进行回归分析,该参数与热感觉投票高度相关。在PMV计算中使用t_(1)代替空气温度对PMV模型进行修正得到tPMV,修正后的tPMV更接近于MTS模型,对PMV起到显著有效的修正作用。

NUMERICAL SIMULATION EXPERIMENTS BY NESTING HYDROLOGY MODEL DHSVM WITH REGIONAL CLIMATE MODEL RegCM2/CHINA

Based on improvement of a distributed hydrology-soil-vegetation model (DHSVM for short) and its application to North China,a nested regional climatic-hydrologic model system is developed by connecting DHSVM with RegCM2/China.The simulated climate scenarios,including control and 2×CO_2 outputs,are downscaled to 8 stations in Luanhe River and Sanggan River Basins to drive the hydrology model.According to simulation results,under double CO_2 scenarios,annual mean temperature and evapotranspiration will increase 2.8C and 29 mm,respectively; precipitation also increase but with different value for each basin,6 mm for Luanhe River Basin while 46 mm for Sanggan River Basin;runoff change for the two basins is different too,27 mm decrease for Luanhe River Basin while 26 mm increase for Sanggan River Basin.As a result,the runoff in future for Luanhe River Basin and Sanggan River Basin will be 74 mm and 71 mm, respectively,which is approximately a quarter of annual mean runoff(284 mm)of the whole country.Total streamflow for the two basins will decrease about 2.5×10~8m^3.All these indicate that the warm and dry trend will continue in the two river basins under double CO_2 scenarios.The nested model system,with both climatic and hydrologic prediction ability,could also be applied to other basins in China by parameter adjustment.

城市户籍人口规模增长预测及其对地区GDP的影响——以南京市为例

以南京市为例,探讨城市户籍人口规模增长对地区生产总值的影响。采用线性回归模型、Holt’s线性趋势模型、ARIMA模型、Logistic增长模型、多元线性回归与BP神经网络等多种计量经济学方法预测南京市户籍人口增长趋势,分析其对经济发展的作用。研究结果表明,人口增长与GDP增长呈正相关性,人口增长对经济发展具有推动作用,多种模型的综合应用提升了预测结果的稳定性与准确性。考虑人口增长的质量与结构变化对经济的影响,强调人口特征在经济发展过程中的重要性,可以为城市规划与区域经济战略制定提供理论与实践参考。

Data generative machine learning model for the assessment of outdoor thermal and wind comfort in a northern urban environment

Predicting comfort levels in cities is challenging due to the many metric assessment.To overcome these challenges,much research is being done in the computing community to develop methods capable of generating outdoor comfort data.Machine Learning(ML)provides many opportunities to discover patterns in large datasets such as urban data.This paper proposes a data-driven approach to build a predictive and data-generative model to assess outdoor thermal comfort.The model benefits from the results of a study,which analyses Computational Fluid Dynamics(CFD)urban simulation to determine the thermal and wind comfort in Tallinn,Estonia.The ML model was built based on classification,and it uses an opaque ML model.The results were evaluated by applying different metrics and show us that the approach allows the implementation of a data-generative ML model to generate reliable data on outdoor comfort that can be used by urban stakeholders,planners,and researchers.

Numerical Investigation and Uncertainty Analysis of Eastern China's Large-Scale Urbanization Effect on Regional Climate

Eastern China has experienced rapid urbanization during the past four decades,and it is necessary to understand the impacts of the urbanization on the regional climate.Previous simulations with either regional climate models(RCMs)or general circulation models have produced inconsistent and statistically non-significant urbanization effects on precipitation during the East Asian summer monsoon.In the studies with RCMs,reanalysis data were used as the lateral boundary conditions(LBCs)for both urban and non-urban experiments.Since the same LBCs may limit the urbanization effect,in this study,the Weather Research and Forecasting(WRF)model nested within the Global Forecast System(GFS),both of which were coupled with an urban canopy model,were used to explore the urbanization effect over eastern China.The WRF’s LBCs in the runs with/without urbanization were provided by the corresponding GFS runs with/without urbanization.The results showed a significant decrease in precipitation over North China,mainly due to a marked decrease in evaporation and the divergence induced by the reduced latent heating in the mid and upper atmosphere,from the experiment with urbanization.Meanwhile,to the north and south of the large-scale urbanization areas,especially to the south of the Yangtze River,precipitation increased significantly due to largescale urbanization-induced circulation change.With the same LBCs for the WRF runs with/without urbanization,the urbanization effects were limited only to urban and nearby areas;no significant change was found to the south of the Yangtze River,since the same LBCs hampered the effects of urbanization on large-scale circulation.In addition,this study demonstrated that the urban fraction may be a key factor that affects the intensity of the urbanization effect within the urban areas.

基于平衡理论与灰色预测模型的区域路网综合调度指标优化研究

文章旨在应用平衡理论和灰色预测模型,结合实际数据进行预测和调度策略优化,以期实现城市交通的智能化管理和精准调控。通过对北京城市区域路网的调查与数据处理,得出了优化后的交通指标与拥堵改善效果,并对平衡理论与灰色预测模型的综合应用效果进行评估与分析。

中国业务动力季节预报的进展

利用动力模式开展季节到年际的短期气候预测 ,是目前国际上气候预测的发展方向。自 1996年以来 ,经过 8a多的研制和发展 ,国家气候中心已建立起第 1代动力气候模式预测业务系统 ,其中包括 1个全球大气 海洋耦合模式 (CGCM )、1个高分辨率东亚区域气候模式 (RegCM_NCC)和 5个简化的ENSO预测模式 (SAOMS) ,可用于季节—年际时间尺度的全球气候预测 ;全球海气耦合模式与区域气候模式嵌套 ,可以提供高分辨率的东亚区域气候模式制做季节预测。CGCM对 1982～ 2 0 0 0年夏季的历史回报试验表明 ,该模式对热带太平洋海表面温度和东亚区域的季节预测具有较好的预测能力。RegCM NCC的 5a模拟基本上能再现东亚地区主要雨带的季节进展。利用嵌套的区域气候模式RegCM NCC对 1991～ 2 0 0 0年的夏季回报表明 ,在预报主要季节雨带方面有一定技巧。 2 0 0 1～ 2 0 0 3年 ,CGCM和RegCM NCC的实时季节预报与观测相比基本合理。特别是 ,模式成功地预报了 2 0 0 3年梅雨季节长江和黄河之间比常年偏多的降水。SAOMS模式系统的回报试验表明 ,该系统对热带太平洋海表面温度距平有一定的预报能力 ,模式超前 6～ 12个月的回报与观测的相关系数明显高于持续预报。 1997～ 2 0 0 3年 。

城市局地热气候预测及热岛效应缓解策略

为量化分析下垫面对局地热环境的影响,采用多用途建筑区域热气候评价模型,以深圳国际低碳城核心启动区为对象,讨论下垫面构成对热岛强度及热舒适性的影响.研究表明:最大局地热岛强度体现最热极端情况的气候差异,平均局地热岛强度反映全天气温的平均差异;夜间平均局地热岛强度高于白天;自然下垫面中,增大水体和树木的覆盖率起到的降温效果更好,而适当增加草地的覆盖率能更有效地提高室外环境舒适度.

城市规划实践中的热气候评价

为量化评价城市规划方案对城市热气候的影响,提出了适用于城市区域热气候预测模型的不同下垫面传热、蓄热和蒸发量计算方法.以北京地区某大型生态城规划项目为实例,引入城市区域局部温升作为评价指标.利用该计算模型和该指标,分析了规划方案实施前后该区域热气候变化程度,并与常规规划方案进行比较,说明在夏季高温、太阳辐射较大的情况下,通过有效的规划设计(提高绿地和树木面积率、降低建筑能耗和减少建筑排热等),可以显著缓解城市化过程对热气候的影响.

降尺度方法在东亚气候预测中的应用

东亚气候变异十分复杂,全球动力预测系统对该地气候异常的预测能力偏低,如何进一步提高东亚地区气候异常的预测水平是一个非常重要的科学和现实需求问题。为此,近些年一系列的动力和统计降尺度方法得以发展。本文主要回顾了这些降尺度方法在东亚气候预测研究和实时预测中的应用。首先,文中简要介绍了我国目前应用于实时预测的全球动力预测系统及其性能,这是开展降尺度的科学和技术基础;在此基础上,从区域模式物理过程参数化方案的评估与遴选、区域模式在东亚气候预测中的应用两个方面,对于动力降尺度方法的发展和应用做了回顾;在统计降尺度的综述中,本文主要关注了东亚夏季汛期和冬季气候异常的预测,特别是针对东亚冬季气候异常,本文中提出了新的高效的统计与动力相结合的预测方法。最后,展望了短期气候预测需要进一步深入研究的科学和技术问题。

基于GIS的陕西省年降水量空间分布特征分析

通过对陕西及周边地区观测的年降水数据进行趋势面和逐步回归分析,建立了宏观地理因子与降水的预测模型,通过小地形订正,获取空间分辨率为100m×100m的降水资源空间分布。结果表明,陕西年降水资源分布差异很大,从陕南秦巴山区的1700mm到陕北风沙滩地的300mm,从南到北呈明显的递减趋势,且山区降水多于河谷、盆地,形成水田、旱地、灌溉等不同的农业类型区。

实况海温强迫的CCM3模式对中国区域气候的模拟能力

使用NCAR/CCM3全球环流模式进行了 5个集合 1 9年 ( 1 979～ 1 997)时间长度的观测海温强迫的AMIP2试验 ,对结果的中国区域部分进行了重点分析。首先给出了模式对中国地区基本气候态的模拟 ,表明模式对这些区域的气温有较好的模拟效果 ,对降水的模拟效果则比较差。随后 ,考察了模式对历年中国汛期降水和气温的模拟预测 ,结果表明 ,模式对中国整体降水的模拟预测能力较差 ,但分地区看 ,则在长江流域地区的效果较好 ;模式对中国汛期气温有较好的模拟能力 。

气候变化对海河流域水文特性的影响

本文应用大尺度陆面水文模型———可变下渗能力模型VIC(VariableInfiltrationCapacity)与区域气候变化影响研究模型PRECIS(ProvidingRegionalClimateforImpactsStudies)耦合,对气候变化情景下海河流域水资源的变化趋势进行预测。结果表明:未来气候情景下,即使海河流域降水量增加,年平均径流量仍将可能减少,预示海河流域的水资源将十分短缺;若考虑21世纪人口增长因素,海河流域的水资源形势将更加严峻;未来气候情景下,汛期的径流量增加,说明海河流域发生洪水的可能性将增大。

江苏省城市经济影响区格局变化

首先运用Mann-Kendall方法将1978年改革开放以来江苏省区域经济发展划分为三个不同阶段。然后采用城市中心性指数和交通时间成本对传统势能模型中的城市规模和距离因子进行了修正,并运用GIS的栅格算法得到主要年份江苏省不同等级中心城市的经济影响区范围,分析其格局变化特征:①南北格局向东西格局转变;②南部经济影响区向北扩展;③苏南地区新中心城市的出现。最后,探讨了江苏省城市经济影响区的变化机制,认为交通轴线的发展状况、经济发展水平和社会生产要素投入差异是导致城市经济影响区格局变化的主要原因。其中,不同的交通轴线对周边地区带动作用差异明显;经济发展水平则显现出苏南一枝独秀,苏中、苏北趋同发展的趋势;生产要素投入中资本、技术投入对经济影响区的格局变化起主导作用。

水文模式DHSVM与区域气候模式RegCM2/China嵌套模拟试验

本研究在改进水文 -土壤 -植被模式DHSVM ,用气候观测资料驱动DHSVM进行模拟试验的基础上 ,建立了区域气候模式RegCM2 /China与水文模式DHSVM的嵌套系统 ,将区域气候模式对中国和东亚地区控制试验 (目前气候情景 )和敏感性试验 (未来 2×CO2 气候情景 )结果用双线性插值方法降尺度 (downscaling)到滦河、桑干河流域的 8个气象站点 ,然后再用数字高程模式DEM插值到DHSVM的细网格点 ,驱动水文模式进行嵌套模拟试验。试验结果表明 ,滦河、桑干河流域在未来大气中CO2 浓度加倍情况下 ,地面气温呈一致的增加趋势 ,年平均气温增加2 .8℃ ;两流域未来降水也呈增加趋势 ,滦河、桑干河流域年降水量分别增加 6mm和 4 6mm ;两流域未来蒸发量有所增加 ,年均蒸发量增加 2 9mm ;未来滦河流域年径流深减少 2 7mm ,流量减少 14 .72× 10 8m3 ,桑干河流域径流深增加 2 6mm ,流量增加 12 .2 2× 10 8m3 ,两流域合计 ,流量减少 2 .5× 10 8m3 ;未来滦河、桑干河流域径流深趋向一致 ,分别为 74和 71mm ,约为全国目前平均径流深 2 84mm的 1/ 4。可见 ,两流域未来总体上仍呈现暖干化趋势。本研究发展的嵌套模式系统具有一定的预测能力 ,而且通过参数移植 。