Evaluating the Dependence of Vegetation on Climate in an Improved Dynamic Global Vegetation Model

The capability of an improved Dynamic Global Vegetation Model （DGVM） in reproducing the impact of climate on the terrestrial ecosystem is evaluated. The new model incorporates the Community Land Model- DGVM （CLM3.0-DGVM） with a submodel for temperate and boreal shrubs, as well as other revisions such as the ＂two-leaf＂ scheme for photosynthesis and the definition of fractional coverage of plant functional types （PFTs）. Results show that the revised model may correctly reproduce the global distribution of temperate and boreal shrubs, and improves the model performance with more realistic distribution of di？erent vege- tation types. The revised model also correctly reproduces the zonal distributions of vegetation types. In reproducing the dependence of the vegetation distribution on climate conditions, the model shows that the dominant regions for trees, grasses, shrubs, and bare soil are clearly separated by a climate index derived from mean annual precipitation and temperature, in good agreement with the CLM4 surface data. The dominant plant functional type mapping to a two dimensional parameter space of mean annual temperature and precipitation also qualitatively agrees with the results from observations and theoretical ecology studies.

Improving microwave brightness temperature predictions based on Bayesian model averaging ensemble approach

The choices of the parameterizations for each component in a microwave emission model have significant effects on the quality of brightness temperature （Tb） sim- ulation. How to reduce the uncertainty in the Tb simulation is investigated by adopting a statistical post-processing procedure with the Bayesian model averaging （BMA） ensemble approach. The simulations by the community microwave emission model （CMEM） cou- pled with the community land model version 4.5 （CLM4.5） over China's Mainland are con- ducted by the 24 configurations from four vegetation opacity parameterizations （VOPs）, three soil dielectric constant parameterizations （SDCPs）, and two soil roughness param- eterizations （SRPs）. Compared with the simple arithmetical averaging （SAA） method, the BMA reconstructions have a higher spatial correlation coefficient （larger than 0.99） than the C-band satellite observations of the advanced microwave scanning radiometer on the Earth observing system （AMSR-E） at the vertical polarization. Moreover, the BMA product performs the best among the ensemble members for all vegetation classes, with a mean root-mean-square difference （RMSD） of 4 K and a temporal correlation coefficient of 0.64.

上海市实施整合式慢性病社区健康管理模式的促进和障碍因素

目的分析整合式慢性病社区健康管理模式实施的促进和障碍因素,区分模式服务量高覆盖率组和低覆盖率组在实施性研究的整合性理论框架(consolidated framework for implementation research,CFIR)上的结构差异,为政府部门提供政策建议。方法结合CFIR对22名专家进行半结构化访谈,采用定性结构评级法对13家社区卫生服务中心受访者评分,利用NVivo 12软件编码。结果高覆盖率组和低覆盖率组的相对优势、外部政策与激励、实施准备度、反思和评价、领导个人特质5个CFIR结构有差异。促进因素包括:测量数据更加精准,提高了高血压和糖尿病患者的异常检出率和控制率;模式实现了服务、技术、数据“三整合”,优化管理流程,提供管理抓手;基础性和个性化服务结合吸引患者到基层就诊;模式与我国政策背景,初级卫生保健工作和以患者为中心理念兼容;数字化工具的应用减轻医护人员工作负担;领导重视是基础,利益方间的通力合作是重要保障。障碍因素包括:宏观层面缺少卫生行政机构的支持性政策,组织架构和运行机制尚未建立,建设、投入主体以及具体工作规范和流程有待明确;缺乏监督管理机制和质量评估小组;模式推广目标模糊;缺乏规范化系统性的培训计划;为不同群体提供服务存在挑战,缺乏有效的社会面宣传;模式仍须提高需方获得感;社区布局限制了模式的服务提供。结论卫生行政部门应明确模式的建设、运行、投入主体,完善组织架构并明确各利益方的功能定位和职责分工,进一步制定工作规范和工作流程;建立信息反馈机制和质量控制小组并进行定期评估;制定清晰的目标;加大宣传教育,扩大宣传面;利用数字化工具形成良性医患互动机制。

The high-resolution community velocity model V2.0 of southwest China,constructed by joint body and surface wave tomography of data recorded at temporary dense arrays

The Sichuan-Yunnan area is located at the southeastern margin of the Tibetan Plateau,where tectonic movement is strong with deep and large faults distributed in a staggered manner,which results in strong seismic activities and severe earthquake hazards.Since the 21st century,several earthquakes of magnitude 7.0 or above occurred in this region,which have caused huge casualties and economic losses,especially the 2008 M_(s)8.0 Wenchuan earthquake.At present,earthquake monitoring and source parameter inversion,strong earthquake hazard analysis and disaster assessment are still the focus of seismological researches in the Sichuan-Yunnan region.Regional high-precision 3D community velocity models are fundamental for these studies.In this paper,by assembling seismic observations at permanent seismic stations and several temporary dense seismic arrays in this region,we obtained about 7.06 million body wave travel time data(including absolute and differential travel times)using a newly developed artificial intelligence body wave arrival time picking method and about 100,000 Rayleigh wave phase velocity dispersion data in the period range of 5-50 s from ambient noise cross-correlation technique.Based on this abundant dataset,we obtained the three-dimensional high resolution V_p and V_(s)model in the crust and uppermost mantle of southwest(SW)China by adopting the joint body and surface wave travel time tomography method considering the topography effect starting from the first version of community velocity model in SW China(SWChina CVM-1.0).Compared to SWChina CVM-1.0,this newly determined velocity model has higher resolution and better data fitness.It is accepted by the China Seismic Experimental Site as the second version of the community velocity model in SW China(SWChina CVM-2.0).The new model shows strong lateral heterogeneities in the shallow crust.Two disconnected low velocity zones are observed in the middle to lower crust,which is located in the Songpan-Ganzi block and the northern Chuandian block to the west of the Longmenshan-Lijiang-Xiaojinhe fault,and beneath the Xiaojiang fault zone,respectively.The inner zone of the Emeishan large igneous province(ELIP)exhibits a high velocity anomaly,which separates the two aforementioned low velocity anomalies.Low velocity anomaly is also shown beneath the Tengchong volcano.The velocity structures in the vicinity of the 2008 M_(s)8.0 Wenchuan earthquake,the 2013 M_(s)7.0Lushan earthquake and the 2017 M_(s)7.0 Jiuzhaigou earthquake mainly show high V_(p)and V_(s)anomalies and the mainshocks are basically located at the transition zone between the high and low velocity anomalies.Along with the segmentation characteristics of seismic activity,we suggest that areas with significant changes in velocity structures,especially in active fault zones,might have a greater potential to generate moderate to strong earthquakes.

潮汐通道水动力和泥沙的湍参数化效应:南海北部崖门水道

In this study,we conducted numerical experiments to examine the effects of turbulence parameterization on temporal and spatial variations of suspended sediment dynamics.Then,we applied the numerical model to the Yamen Channel,one of the main eight outfalls in the Pearl River Delta.For the field application,we implemented the k−εscheme with a reasonable stability function using the continuous deposition formula during the erosion process near the water-sediment interface.We further validated and analyzed the temporal-spatial suspended sediment concentrations(SSCs).The experimental results show that under specified initial and boundary conditions,turbulence parameterization with stability functions can lead to different vertical profiles of the velocity and SSC.The k−εpredicts stronger mixing with a maximum value of approximately twice the k−kl.The k−kl results in smaller SSCs near the surface layer and a larger vertical gradient than the k−ε.In the Yamen Channel,though the turbulent dissipation,turbulent viscosity and turbulence kinetic energy exhibit similar trends,SSCs differ significantly between those at low water and high water due to the tidal asymmetry and settling lag mechanisms.The results can provide significant insights into environmental protection and estuarine management in the Pearl River Delta.

SST effect on the pre-monsoon intraseasonal oscillation over the South China Sea based on atmospheric-coupled GCM comparison

The role of sea surface temperature(SST)variability in the pre-monsoonal(April to July)intraseasonal oscillation(ISO)over the South China Sea(SCS)is investigated using the Community Earth System Model Version 2(CESM2).An Atmospheric Model Intercomparison Project(AMIP)simulation forced by daily sea surface temperatures(SSTs)derived from a parallel coupled general circulation model(CGCM)run was compared with observations and the mother coupled simulation.In the coupled model,the SST warming leads the peak convection about 1/4 period as in observations.The paralell uncoupled model fails to simulate this phase relationship,implying the importance of air-sea coupling in reproducing realistic ISO.Due to the near-quadrature phase relationship between SST and precipitation ISOs during the ISO events,it is difficult to distinguish the active/passive role of SST from observations alone.Significant correlation in intraseasonal precipitation between the daily SST-forced AMIP and mother CGCM runs indicates that SST plays a role in driving the atmospheric ISO.

China Seismic Experimental Site(CSES): Challenges of Deep Earth Exploration and Practice(DEEP)

Since May 2018,the planning,construction and functioning of China Seismic Experimental Site(CSES)has attracted much attention in earthquake science(CSES,2020 a,b,c;Wu,2020;Li et al.,2021).Different from traditional earthquake prediction experiment projects,such as the Parkfield earthquake prediction experiment(Roeloffs,2000).

东南沿海台风风暴潮增水过程中非线性机制和地形的作用研究:以1509号台风“灿鸿”为例

本文基于FVCOM(Finite Volume Community Ocean Model)构建了一个覆盖中国渤海、黄海和东海的数值模型,采用NCEP-CFSR风场数据对1509号台风“灿鸿”产生的风暴潮进行模拟,与实测水位数据的对比表明该模型可靠、模拟结果合理。基于此模型,本文对非线性作用和地形在风暴潮增水过程中的作用进行了研究。首先,重点分析了增水过程中潮汐与风暴潮的非线性作用,结果表明:高潮时非线性作用使增水值降低;低潮时非线性作用使增水值升高。另外,开边界处分别只添加M2、S2和K1分潮,分析天文潮的潮高和周期对非线性作用的影响,结果表明:潮高越高,非线性作用越明显;半日潮的非线性作用较全日潮更明显;并且,增水极值附近出现的半日周期的波动也与非线性作用有关。其次,除了非线性作用,地形对风暴潮的增水也有一定影响,本文改变地形的实验结果表明:坡度越大,增水极值越小。琉球群岛的存在使得东南沿海出现风暴潮增水的面积减小,但使得风暴潮增水的高值区域扩大。

A Numerical Study of Tropospheric Ozone in the Springtime in East Asia

The Models-3 Community Multi-scale Air Quality modeling system (CMAQ) coupled with the Regional Atmospheric Modeling System (RAMS) is applied to East Asia to study the transport and photochemical transformation of tropospheric ozone in March 1998. The calculated mixing ratios of ozone and carbon monoxide are compared with ground level observations at three remote sites in Japan and it is found that the model reproduces the observed features very well. Examination of several high episodes of ozone and carbon monoxide indicates that these elevated levels are found in association with continental outflow, demonstrating the critical role of the rapid transport of carbon monoxide and other ozone precursors from the continental boundary layer. In comparison with available ozonesonde data, it is found that the model-calculated ozone concentrations are generally in good agreement with the measurements, and the stratospheric contribution to surface ozone mixing ratios is quite limited.

Runoff of arid and semi-arid regions simulated and projected by CLM-DTVGM and its multi-scale fluctuations as revealed by EEMD analysis

Runoff is a major component of the water cycle, and its multi-scale fluctuations are important to water resources management across arid and semi-arid regions. This paper coupled the Distributed Time Variant Gain Model （DTVGM） into the Community Land Model （CLM 3.5）, replacing the TOPMODEL-based method to simulate runoff in the arid and semi-arid regions of China. The coupled model was calibrated at five gauging stations for the period 1980-2005 and validated for the period 2006-2010. Then, future runoff （2010-2100） was simulated for different Representative Concentration Pathways （RCP） emission scenarios. After that, the spatial distributions of the future runoff for these scenarios were discussed, and the multi-scale fluctuation characteristics of the future annual runoff for the RCP scenarios were explored using the Ensemble Empirical Mode Decomposition （EEMD） analysis method. Finally, the decadal variabilities of the future annual runoff for the entire study area and the five catchments in it were investigated. The results showed that the future annual runoff had slowly decreasing trends for scenarios RCP 2.6 and RCP 8.5 during the period 2010-2100, whereas it had a non-monotonic trend for the RCP 4.5 scenario, with a slow increase after the 2050s. Additionally, the future annual runoff clearly varied over a decadal time scale, indicating that it had clear divisions between dry and wet periods. The longest dry period was approximately 15 years （2040-2055） for the RCP 2.6 scenario and 25 years （2045-2070） for the RCP 4.5 scenario. However, the RCP 8.5 scenario was predicted to have a long dry period starting from 2045. Under these scenarios, the water resources situation of the study area will be extremely severe. Therefore, adaptive water management measures addressing climate change should be adopted to proactively confront the risks of water resources.

Source Contributions to PM2.5 under Unfavorable Weather Conditions in Guangzhou City,China

Historical haze episodes（2013–16） in Guangzhou were examined and classified according to synoptic weather systems.Four types of weather systems were found to be unfavorable, among which ＂foreside of a cold front＂（FC） and ＂sea high pressure＂（SP） were the most frequent（〉 75% of the total）. Targeted case studies were conducted based on an FC-affected event and an SP-affected event with the aim of understanding the characteristics of the contributions of source regions to fine particulate matter（PM（2.5）） in Guangzhou. Four kinds of contributions—namely, emissions outside Guangdong Province（super-region）, emissions from the Pearl River Delta region（PRD region）, emissions from Guangzhou–Foshan–Shenzhen（GFS region）, and emissions from Guangzhou（local）—were investigated using the Weather Research and Forecasting–Community Multiscale Air Quality model. The results showed that the source region contribution differed with different weather systems. SP was a stagnant weather condition, and the source region contribution ratio showed that the local region was a major contributor（37%）, while the PRD region, GFS region and the super-region only contributed 8%, 2.8% and 7%, respectively, to PM（2.5） concentrations. By contrast, FC favored regional transport. The super-region became noticeable,contributing 34.8%, while the local region decreased to 12%. A simple method was proposed to quantify the relative impact of meteorology and emissions. Meteorology had a 35% impact, compared with an impact of-18% for emissions, when comparing the FC-affected event with that of the SP. The results from this study can provide guidance to policymakers for the implementation of effective control strategies.

Parameter Sensitivities of the Community Land Model at Two Alpine Sites in the Three-River Source Region

The three-river source region plays an important role on China’s ecological security and Asia’s water supply. Historically, the region has experienced severe ecological degradation due to climate change and human activities. Reasonable simulations of the energy and water cycles are essential to predict the responses of land surface processes to future climate change. Current land surface models involve empirical functions that are associated with many parameters. These parameter uncertainties will largely affect the simulation when applied to a new domain. The Community Land Model(CLM) is a widely used land surface model, and version 5.0 is the newest version. Compared to the prior version CLM4.5, CLM5.0 has largely updated plant hydraulic and stomatal conductance schemes. How these changes affect parameter sensitivities is unknown. In our work, we tested 17 key parameters in CLM4.5 and 19 parameters in CLM5.0 at two eddy flux sites in the three-river source region: the Maqu and Maduo sites. We adopted the simplest one-at-a-time changes on each parameter and quantified their sensitivities by the parameter effect(PE).We found that the Maqu site was more sensitive to vegetation parameters, while the Maduo site was more sensitive to the initial soil water content in both CLM4.5 and CLM5.0. This is because Maduo grid cell has wetland that does not respond to vegetation parameters in CLM, which may not reflect the reality. Further model development on wetland vegetation parameterization is important. Our validation on the default simulation showed CLM5.0 did not always improve the simulations. The largest difference between CLM5.0 and CLM4.5 was that soil moisture(SM) showed a much stronger decrease in response to a higher leaf area index(LAI) in CLM5.0 than in CLM4.5, suggesting that SM is more sensitive to vegetation changes in CLM5.0.

Study on Regulating Effects of "Aquatic Environment Protection Oriented Fishery" on Water Environment of Qiaodun Reservoir

In order to evaluate the regulating effect of ＂ aquatic environment protection oriented fishery＂ on aquatic ecosystem,the water quality,plankton community structure,biomass,diversity index,eutrophication index and ecosystem maturity evaluated with Ecopath model were compared from 2010 to 2012 in Qiaodun Reservoir of Zhejiang Province. It was indicated that the water quality had been improved obviously. The water transparency maximally increased by 130%,while TP,TN and CODCrwere reduced. The density and biomass of the plankton were decreased,so was the ratio of Cynobacteria in phytoplankton community. The Shannon-Weaver index was increased; the trophic level was decreased; the ecosystem maturity was improved. By all accounts,the ＂ aquatic environment protection oriented fishery＂ had positive effects on maintaining the balance of reservoir ecosystem and ensuring the safety of drinking water.

On the Shallowing of Antarctic Low-Level Temperature Inversions Projected by CESM-LE under RCP8.5

Temperature inversions are frequently observed in the boundary layer and lower troposphere of polar regions.Future variations of the low-level temperature inversions in these regions,especially the Antarctic,are still poorly understood.Due to the scarcity of observations in the Antarctic,reanalysis data and numerical simulations are often used in the study of Antarctic climate change.Based on ERA-Interim,ERA5,JRA-55,and NCEP-NCAR reanalysis products,this study examines temporal and spatial variations of Antarctic inversion depth in austral autumn and winter during 1979-2020.Deeper inversions are found to occur over the high plateau areas of the Antarctic continent.Based on the Mann-Kendall test,ERA-Interim and ERA5 data reveal that the Antarctic inversion depth in austral autumn and winter increased during 1992-2007,roughly maintained afterwards,and then significantly decreased since around 2016.The decrease trend is more obvious in the last two months of winter.Overall,JRA-55 better represents the spatial distribution of inversion depth,and ERA-Interim has better interannual variability.The Community Earth System Model Large Ensemble(CESM-LE)30-member simulations in 1979-2005 were first verified against JRA-55,showing reasonable consistency,and were then used to project the future changes of Antarctic low-level inversion depth over 2031-2050 under RCP8.5.The CESM-LE projection results reveal that the temperature inversion will shallow in the Antarctic at the end of the 21st century,and the decrease in depth in autumn will be more pronounced than that in winter.In particular,the temperature inversion will weaken over the ice-free ocean,while it will remain stable over the ice sheet,showing certain spatial heterogeneity and seasonal dependence on the underlying cryospheric surface conditions.In addition,the decrease of inversion depth is found closely linked with the reduction in sea ice,suggesting the strong effect of global warming on the thermal structure change of the Antarctic.

Modeling Study of the Efect of Anthropogenic Aerosols on Late Spring Drought in South China

In this study,the mechanisms underlying the decadal variability of late spring precipitation in South China are investigated by using the latest Community Earth System Model version 1 （CESM1）.We aim to unravel the effects of different climate forcing agents such as aerosols and greenhouse gases （GHGs） on the decadal variation of precipitation,based on transient experiments from pre-industry （for year 1850） to present-day （for year 2000）.Our results reveal that：（1） CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in South China; （2） only simulations including the forcing of anthropogenic aerosols can reproduce the observed decreasing trend of late spring precipitation from 1950-2000 in South China; （3） aerosols affect the decadal change of precipitation mainly by altering the large-scale atmospheric circulation,and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and （4） in comparison,other climate forcing agents such as GHGs have much smaller effects on the decadal change of spring precipitation in South China.

Fast Community Detection Based on Distance Dynamics

The distance dynamics model is excellent tool for uncovering the community structure of a complex network. However, one issue that must be addressed by this model is its very long computation time in large-scale networks. To identify the community structure of a large-scale network with high speed and high quality, in this paper, we propose a fast community detection algorithm, the F-Attractor, which is based on the distance dynamics model. The main contributions of the F-Attractor are as follows. First, we propose the use of two prejudgment rules from two different perspectives： node and edge. Based on these two rules, we develop a strategy of internal edge prejudgment for predicting the internal edges of the network. Internal edge prejudgment can reduce the number of edges and their neighbors that participate in the distance dynamics model. Second, we introduce a triangle distance to further enhance the speed of the interaction process in the distance dynamics model. This triangle distance uses two known distances to measure a third distance without any extra computation. We combine the above techniques to improve the distance dynamics model and then describe the community detection process of the F-Attractor. The results of an extensive series of experiments demonstrate that the F-Attractor offers high-speed community detection and high partition quality.

The Dynamical and Climate Tests of an Atmospheric General Circulation Model Using the Second-Order Adams-Bashforth Method

The Asselin-Robert time filter used in the leapfrog scheme can degrade the accuracy of calculations.The second-order Adams-Bashforth method with the same accuracy as the leapfrog scheme is not subject to time splitting instability.A new semi-implicit atmospheric general circulation spectral model is developed on the basis of NCAR（National Center for Atmospheric Research）CAM3.0（Community Atmosphere Model 3.0）.In this new model,the second-order Adams-Bashforth method is used as an alternative to the leapfrog scheme,and a Crank-Nicholson scheme is incorporated for the treatment of fast gravity modes.In this paper,the new model is tested by the Held-Suarez test and an idealized baroclinic wave test.Results of the Held-Suarez test show that the second-order Adams-Bashforth model has similar climate states to those of many other global models and it converges with resolutions.Based on the idealized baroclinic wave test,the capability of different time differencing methods for keeping the initial steady-state are compared. This convinces a better ability of the second-order Adams-Bashforth method in maintaining the stability of the initial state.Furthermore,after the baroclinic wave is triggered through overlaying the steady-state initial conditions with the zonal perturbation,the second-order Adams-Bashforth method has an excellent property of convergence,and can represent the process of the baroclinic wave development much better than the original scheme in CAM3.0.A long-term integration of the new model during the period of 1980–1999 is also carried out and compared with that of CAM3.0.It is found that due to the reduction of simulation errors of prognostic variables,the second-order Adams-Bashforth method also has a better simulation ability for the diagnostic variables,such as precipitation.

Estimates of net primary productivity and actual evapotranspiration over the Tibetan Plateau from the Community Land Model version 4.5 with four atmospheric forcing datasets

The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models(LSM).Particularly in high-altitude regions,choosing appropriate atmospheric forcing datasets can effectively reduce uncertainties in the LSM simulations.Therefore,this study conducted four offline LSM simulations over the Tibetan Plateau(TP)using the Community Land Model version 4.5(CLM4.5)driven by four state-of-the-art atmospheric forcing datasets.The performances of CRUNCEP(CLM4.5 model default)and three other reanalysis-based atmospheric forcing datasets(i.e.ITPCAS,GSWP3 and WFDEI)in simulating the net primary productivity(NPP)and actual evapotranspiration(ET)were evaluated based on in situ and gridded reference datasets.Compared with in situ observations,simulated results exhibited determination coefficients(R2)ranging from 0.58 to 0.84 and 0.59 to 0.87 for observed NPP and ET,respectively,among which GSWP3 and ITPCAS showed superior performance.At the plateau level,CRUNCEP-based simulations displayed the largest bias compared with the reference NPP and ET.GSWP3-based simulations demonstrated the best performance when comprehensively considering both the magnitudes and change trends of TP-averaged NPP and ET.The simulated ET increase over the TP during 1982-2010 based on ITPCAS was significantly greater than in the other three simulations and reference ET,suggesting that ITPCAS may not be appropriate for studying long-term ET changes over the TP.These results suggest that GSWP3 is recommended for driving CLM4.5 in conducting long-term carbon and water processes simulations over the TP.This study contributes to enhancing the accuracy of LSM in water-carbon simulations over alpine regions.

Modeling Study of Foehn Wind Events in Antarctic Peninsula with WRF Forced by CCSM

Significant changes have occurred in the Antarctic Peninsula(AP) including warmer temperatures, accelerated melting of glaciers, and breakup of ice shelves. This study uses the Weather Research and Forecasting model(WRF)forced by the Community Climate System Model 4(CCSM) simulations to study foehn wind warming in AP. Weather systems responsible for generating the foehn events are two cyclonic systems that move toward and/or cross over AP. WRF simulates the movement of cyclonic systems and the resulting foehn wind warming that is absent in CCSM. It is found that the warming extent along a transect across the central AP toward Larsen C Ice Shelf(LCIS) varies during the simulation period and the maximum warming moves from near the base of leeward slopes to over 40 km away extending toward the attached LCIS. Our analysis suggests that the foehn wind warming is negatively correlated with the incoming air temperature and the mountain top temperature during periods without significant precipitation, in which isentropic drawdown is the dominant heating mechanism. On the other hand, when significant precipitation occurs along the windward side of AP, latent heating is the major heating mechanism evidenced by positive relations between the foehn wind warming and 1) incoming air temperature, 2) windward precipitation, and 3)latent heating. Foehn wind warming caused by isentropic drawdown also tends to be stronger than that caused by latent heating. Comparison of WRF simulations forced by original and corrected CCSM data indicates that foehn wind warming is stronger in the original CCSM forced simulation when no significant windward precipitation is present.The foehn wind warming becomes weaker in both simulations when there is significant windward precipitation. This suggests that model’s ability to resolve the foehn warming varies with the forcing data, but the precipitation impact on the leeward warming is consistent.

Impact of energy structure adjustment on air quality:a case study in Beijing,China

Energy consumption is a major cause of air pollution in Beijing,and the adjustment of the energy structure is of strategic importance to the reduction of carbon intensity and the improvement of air quality.In this paper,we explored the future trend of energy structure adjustment in Beijing till 2020,designed five energy scenarios focusing on the fuel substitution in power plants and heating sectors,established emission inventories,and utilized the Mesoscale Modeling System Generation 5(MM5)and the Models-3/Community Multiscale Air Quality Model(CMAQ)to evaluate the impact of these measures on air quality.By implementing this systematic energy structure adjustment,the emissions of PM_(10),PM_(2.5),SO_(2),NO_(x),and non-methane volatile organic compounds(NMVOCs)will decrease distinctly by 34.0%,53.2%,78.3%,47.0%,and 30.6%respectively in the most coalintensive scenario of 2020 compared with 2005.Correspondingly,MM5-Models-3/CMAQ simulations indicate significant reduction in the concentrations of major pollutants,implying that energy structure adjustment can play an important role in improving Beijing’s air quality.By fuel substitution for power plants and heating boilers,PM_(10),PM_(2.5),SO_(2),NO_(x),and NMVOCs will be reduced further,but slightly by 1.7%,4.5%,11.4%,13.5%,and 8.8%respectively in the least coal-intensive scenario.The air quality impacts of different scenarios in 2020 resemble each other,indicating that the potential of air quality improvement due to structure adjustment in power plants and heating sectors is limited.However,the CO_(2) emission is 10.0%lower in the least coal-intensive scenario than in the most coal-intensive one,contributing to Beijing’s ambition to build a low carbon city.Except for energy structure adjustment,it is necessary to take further measures to ensure the attainment of air quality standards.