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1.
利用国家气象中心中尺度业务数值预报模式GRAPES-MESO v3.0,以2010年6月1~30日为例,开展地面降水率1DVAR(one-dimensional variational assimilation)同化方案在GRAPES-3DVAR(three-dimensional variational assimilation)同化系统中的应用试验研究(ASSI试验),并以未加降水资料同化的试验为对照试验(CNTL试验),以评估全国1h加密雨量资料在模式中同化应用的效果。结果表明:1)在相对湿度背景误差和降水率观测误差范围内,1DVAR同化方案能够对湿度廓线进行有意义的调整,使分析降水向观测降水靠近;ASSI试验对初始温、压、湿、风场的修正主要为正效果;2)对2010年6月17~21日江南、华南连续性降水过程进行了分析,整体而言ASSI试验对逐日及逐时降水强度的预报普遍强于CNTL试验,与实况更加接近;3)ASSI试验对2010年6月1~30日08时起报的0~24 h模式预报的小雨、中雨、大雨、暴雨、大暴雨各个降水量级TS评分及ETS评分相比CNTL试验均有较明显提高,预报偏差也更接近于1;4)ASSI试验较CNTL试验能更好地模拟雨带的分布、雨带演变特征和降水强度的变化;5)对降水所做的典型个例和统计检验分析从不同角度说明了地面降水资料1DVAR同化方案在GRAPES-3DVAR系统中的应用改善了GRAPES-MESO v3.0的降水模拟效果。  相似文献   

2.
降水资料同化在梅雨锋特大暴雨个例模拟中的应用研究   总被引:4,自引:1,他引:3  
利用暴雨数值预报模式AREM,以2009年6月29日发生在长江中下游地区的一次梅雨锋特大暴雨过程为例,以NCEP预报场为背景场,首先开展了不同化任何资料(无同化试验)以及分别利用GRAPES-3DVAR同化系统和局地分析预报系统(LAPS)同化地面、探空资料的3组数值试验,然后进一步开展了降水资料一维变分同化方法在GRAPES-3DVAR同化系统及LAPS系统中二次同化的效果研究,结果表明:(1)采用GRAPES-3DVAR系统同化地面、探空资料的数值试验,其降水预报效果不如无同化试验结果;而采用LAPS资料同化系统同化地面、探空资料的数值试验,其降水预报效果优于无同化试验结果,即就本个例而言,GRAPES-3DVAR同化系统对背景场的修正为负效果,LAPS同化系统对背景场的修正为正效果。(2)降水资料1DVAR方法在GRAPES-3DVAR同化系统中的应用,对物理量场有重要影响,使雨带上空变得更暖更湿,天气系统的配置更利于降水发生,中尺度系统的演变更有利于模拟出与实况更加接近的雨带位置、强度、中尺度结构特征,因而极大地改善了降水模拟效果,其模拟的1、6、24h累积降水量位置、强度、中尺度结构特征都有较明显改善。(3)降水资料1DVAR方法在LAPS系统中的应用同样改善了降水预报效果,使雨带落区位置更加接近实况。  相似文献   

3.
基于暴雨数值预报模式AREM,以2008年5月21日—7月30日为例,开展了以LAPS系统和GRAPES-3DVAR系统两种不同初值方案同化相同资料源(NCEP预报场、地面、探空资料)的AREM-LAPS和AREM-3DVAR试验,以探讨两种初值分析方案对降水模拟的影响。结果表明:(1)AREM-LAPS试验与AREM-3DVAR试验相比,各区域、各量级、各时效的降水预报在绝大多数情况下TS评分有较明显提高,特别是大雨、暴雨、大暴雨等强降水等级。(2)AREM-3DVAR试验可以大致模拟出与实况比较相近的平均降水量分布,但预报雨区范围偏小,强度偏弱;AREM-LAPS试验对此有较明显改善。(3)AREM-LAPS较AREM-3DVAR试验更好地模拟出了降水雨带的南北摆动及降水强度的变化。(4)AREM-LAPS试验较好地再现了我国西南地区东部、华南沿海、长江中下游-淮河流域及胶东半岛主要雨带区平均降水率逐日降水增强与减弱的过程,其强度也与实况大体相当;而AREM-3DVAR试验模拟的强度则明显偏弱,特别是我国西南地区东部。(5)对2008年夏季10余次典型降水过程的对比检验表明,AREM-LAPS对雨带范围、位置、强度的预报都好于AREM-3DVAR,特别是对于降水强度的改进尤为突出。  相似文献   

4.
基于有限区域中尺度暴雨预报模式AREM,利用常德、荆州、宜昌3部多普勒雷达及武汉数字化天气雷达联合反演的1h降水量资料和宜昌、荆州多普勒雷达反演的水平风场资料,采用3种不同的初值方案:Grapes-3DVAR同化方案、Barnes客观分析法及Barnes-3DVAR同化方案,对2002年7月22日20:00—23日20:00发生在长江流域的一次大暴雨过程进行了多普勒雷达估算降水和反演风场在不同初值方案下对降水预报影响的数值试验,结果表明:(1)采用相同资料源(探空 T213L31分析场),3种初值方案降水模拟效果差别显著。整体而言,融合了Barnes和3DVAR两种方案的Barnes-3DVAR初值方案降水模拟效果最好:雨带模拟完整,位置与实况完全一致;降水中心中尺度结构清晰,位置、强度与实况接近。(2)Barnes-3DVAR同化方案与Grapes-3DVAR同化方案都能同化雷达降水和风场资料,但两者降水预报结果相差很大。Barnes-3DVAR方案下的降水模拟结果明显好于Grapes-3DVAR同化方案。(3)Grapes-3DVAR同化方案下,在控制试验的基础上增加雷达降水资料的同化,24h降水模拟效果有所改善;增加雷达风场资料的同化,仅部分改善模拟效果,某些地方效果反而变差;同时增加雷达降水和风场资料的同化,降水模拟效果反而明显变差。Barnes-3DVAR同化方案则不然,无论雷达降水资料和风场资料单独同化还是两种资料同时同化,降水模拟效果都有不同程度的改进,特别是对雷达降水和风场资料同时同化的模拟结果是各种试验中效果最好的。(4)融合Barnes客观分析方法和Grapes-3DVAR同化方案的Barnes-3DVAR同化方案,是同化雷达降水和风场资料的一种新的、有效的初值方案。  相似文献   

5.
利用合肥站雷达资料和NCEP再分析资料,采用WRF模式、WRF-3DVAR和WRF-En SRF同化系统设计了直接同化雷达径向风和反射率的试验,对2003年7月4—5日发生在江淮流域的一次梅雨锋暴雨过程进行数值模拟分析。结果表明:(1)同化雷达径向风资料可以增加暴雨区低层的扰动,增强对流运动,同时可以减少模拟的过量降水;(2)3DVAR同化方法对水平风场调整明显,同化反射率改进了模式中的微物理量和动力场,同时同化径向风和反射率可以更好地调整风场,改善模拟雷达回波带的强度和位置;(3)En SRF同化方法可以将更多小尺度的风场信息同化进入模式,单独同化反射率可以较准确预报出降水中心,同时同化径向风和反射率可以改进模拟雷达回波带的位置;(4)使用3DVAR和En SRF同化雷达径向风和反射率可以提高降水预报,改善雨带的范围,对降水中心位置和强度的预报也有改进。  相似文献   

6.
《气象与环境学报》2017,(江西省汛)
利用24 h降水实况资料和高空实况形势场资料、ECMWF模式形势场预报资料及ECMWF、JMA、T639模式降水预报资料,对2015年江西省汛期(4月上旬至7月上旬)区域性暴雨的时空分布特征进行分析,并对2015年江西省汛期区域性暴雨的影响系统和降水预报结果进行了短期主观检验,对比分析了ECMWF、JMA和T639等3种数值模式对江西省区域性暴雨系统预报的效果。结果表明:ECMWF模式对江西省汛期暴雨天气系统的调整和演变具有一定的预报能力,如对副热带高压和西南急流的预报;但随着预报时效增加,预报误差增大。ECMWF模式预报的48 h和72 h副热带高压强度较实况明显偏弱,预报的副热带高压西脊点位置偏东,随着季节转变预报的副热带高压强度明显偏弱,其中24 h预报的准确率较高。ECMWF模式对高空槽的预报基本准确;ECMWF模式对切变线移动的总体预报效果较好,72 h预报的切变线移动偏慢;ECMWF模式对700 hPa西南急流强度的预报易偏弱,对850 hPa和925 hPa西南急流的预报易偏强;ECMWF模式预报的急流轴位置多数偏北;ECMWF模式对低层比湿的预报较实况偏强。随着预报时效临近,ECMWF、JMA和T639等3种数值模式对江西省汛期区域性暴雨的预报具有较强的调整能力;JMA模式预报的暴雨与实况最接近,表现出对雨带分布具有较强的预报性能,但对降水量级预报偏弱;ECMWF模式对降水强度的预报性能较好,预报的降水分布总体偏北;T639模式预报的主雨带范围较实况偏大,3个模式均存在对暴雨以上量级降水漏报的问题。  相似文献   

7.
利用24 h降水实况资料和高空实况形势场资料、ECMWF模式形势场预报资料及ECMWF、JMA、T639模式降水预报资料,对2015年江西省汛期(4月上旬至7月上旬)区域性暴雨的时空分布特征进行分析,并对2015年江西省汛期区域性暴雨的影响系统和降水预报结果进行了短期主观检验,对比分析了ECMWF、JMA和T639等3种数值模式对江西省区域性暴雨系统预报的效果。结果表明:ECMWF模式对江西省汛期暴雨天气系统的调整和演变具有一定的预报能力,如对副热带高压和西南急流的预报;但随着预报时效增加,预报误差增大。ECMWF模式预报的48 h和72 h副热带高压强度较实况明显偏弱,预报的副热带高压西脊点位置偏东,随着季节转变预报的副热带高压强度明显偏弱,其中24 h预报的准确率较高。ECMWF模式对高空槽的预报基本准确;ECMWF模式对切变线移动的总体预报效果较好,72 h预报的切变线移动偏慢;ECMWF模式对700 hPa西南急流强度的预报易偏弱,对850 hPa和925 hPa西南急流的预报易偏强;ECMWF模式预报的急流轴位置多数偏北;ECMWF模式对低层比湿的预报较实况偏强。随着预报时效临近,ECMWF、JMA和T639等3种数值模式对江西省汛期区域性暴雨的预报具有较强的调整能力;JMA模式预报的暴雨与实况最接近,表现出对雨带分布具有较强的预报性能,但对降水量级预报偏弱;ECMWF模式对降水强度的预报性能较好,预报的降水分布总体偏北;T639模式预报的主雨带范围较实况偏大,3个模式均存在对暴雨以上量级降水漏报的问题。  相似文献   

8.
采用中尺度数值模式WRF(Weather Research and Forecasting)中FY-3C卫星MWHS-2(Micro-Wave Humidity Sounder 2)卫星资料的直接同化模块,利用WRF-3DVAR(Three Dimensional Variation)方法对三江源地区的两次降水过程进行同化对比试验,详细对比分析了FY-3C搭载的MWHS-2微波湿度仪和NOAA-18(National Oceanic and Atmospheric Administration-18)搭载的MHS(Microwave Humidity Sounder)微波湿度仪两种同化资料对模拟结果的影响。结果表明:MWHS-2和MHS资料同化的模拟结果基本一致,对于30 mm以下的降水,无论同化与否,模拟的降水范围均会偏大;但对于30 mm以上的降水,模拟范围和量级均偏小。资料同化增强了500 hPa西南风场,从而加大了水汽输送的强度,使得高空槽偏向西南,同时加强了300 hPa风场扰动,在共同作用下从而导致了30 mm以上的降水范围的增大,对降水量级结果能有一定改善,但降水落区相较...  相似文献   

9.
一种定量降水预报误差检验技术及其应用   总被引:5,自引:3,他引:2  
符娇兰  宗志平  代刊  张芳华  高栋斌 《气象》2014,40(7):796-805
面向对象检验技术是定量降水预报误差分析方法之一,通过对某一降水过程进行分离,实现对其落区、量级等预报误差的定量化分析。基于面向对象的检验方法和天气系统识别技术,本文利用实况观测资料、ECMWF全球数值模式产品,以2012年汛期西南地区5个典型强降水天气过程作为检验对象,对其降水及天气尺度影响系统1~10 d模式预报误差进行了定量化分析。分析表明:在中短期时效内,模式均对西南地区雨带位置预报偏北、偏西,中期时效内偏差更显著,雨带主轴上70%以上的点预报较实况偏北在2°以内,偏西约3°以内;预报的大雨及以上量级降水量较实况偏弱;模式1~2 d预报的极值分布与实况较为接近,随着预报时效延长,预报的极值较实况明显偏小;模式预报的小雨及以下量级的降水范围较实况偏大,对大雨以上量级的降水范围较实况明显偏小。对于四川盆地而言,预报的切变线较零场偏西0.5°~3°。低空急流预报偏西0.5°~1.5°;低空急流强度预报偏差具有季节差异。  相似文献   

10.
一次大暴雨过程的多普勒雷达资料同化的敏感性试验   总被引:3,自引:1,他引:2  
利用WRF中尺度模式及WRF-3DVAR变分同化系统和LAPS雷达资料前处理模块建立试验平台,直接同化S波段多普勒雷达反射率和径向速度资料,通过对2008年8月15-16日发生在我国长江中游的一次大暴雨过程的各项预报对比试验研究,初步检验和评估不同种类多普勒雷达观测数据同化对改进数值模式初始场及其数值预报能力的影响及作用.初步结果表明:多普勒雷达资料同化对提高暴雨数值预报能力有重要作用.无论在24 h累计降水还是在逐时降水预报方面,同化多普勒雷达资料均可使降水雨带分布和强降水中心预报的准确性得到较大改善;多普勒雷达反射率资料同化对初始水汽场的改变显著,对初始风场影响较小,而同化径向速度对初始水汽场的改变较小,但可增加初始风场的中小尺度信息,使初始风场产生较大变化.总体上看,虽然雷达反射率和径向速度资料同化均可改进强暴雨的数值预报,但雷达反射率资料同化对降水雨带和中心预报的改进更为显著和重要.  相似文献   

11.
The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.  相似文献   

12.
正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on  相似文献   

13.
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography.  相似文献   

14.
The variation of the East Asian jet stream(EAJS) associated with the Eurasian(EU) teleconnection pattern is investigated using 60-yr NCEP–NCAR daily reanalysis data over the period 1951–2010. The EAJS consists of three components: the polar front jet(PFJ); the plateau subtropical jet(PSJ); and the ocean subtropical jet(OSJ). Of these three jets over East Asia,the EU pattern exhibits a significant influence on the PFJ and OSJ. There is a simultaneous negative correlation between the EU pattern and the PFJ. A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days. There is no obvious correlation between the EU pattern and the PSJ. The positive EU phase is accompanied by a weakened and poleward-shifted PFJ, which coincides with an intensified OSJ. A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing. The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ, as well as the northward/southward shift of the PFJ. High- and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ, but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern. The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other. Thus, the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China.  相似文献   

15.
<p>Using the multielements similarity measurement method and 1950–C2017 NCEP/NCAR gridded daily reanalysis datasets, we analyzed season duration in China during 1950–C2016, and we defined the element with maximum absolute sensitivity as the key impact element at each point using the sensitivity analysis method. The decadal change of season duration and its key impact element before and after 1980 were studied. The results indicated obvious meridional and zonal differences in the distribution of season duration for the 67-year average, and that the key impact element has the same distribution characteristics as season duration. In addition, complementary relationships were found between the durations of spring and summer, autumn and winter, and the cold and warm seasons. Of those, the complementary relationship between the durations of spring and summer was strongest and the regions of complementarity were numerous. The complementary regions of autumn and winter durations were found mainly in western China. In the cold and warm seasons, the complementary regions were widespread and the complementary relationship was generally weak. Comparison of the periods before and after 1980 revealed an east–Cwest difference in the interdecadal variation of season duration. Interdecadal variation in spring and summer was found concentrated in northern and western regions, while that in autumn and winter was concentrated in the western region. Areas of significant interdecadal variation of the key elements were found concentrated in northern and western regions, corresponding well with the areas of significant interdecadal variation of season duration.</p>  相似文献   

16.
By using the gauged rainfall in 160 stations within mainland China and the NCEP/NCAR reanalysis data, the impacts of anomalous SST in Kuroshio and its extension on precipitation in Northeast China were investigated. The results show that a difference in the meridional circulation such as the East Asia/Pacific teleconnection pattern(EAP)may be responsible for the difference in rainfall between 1998 and 2010. In comparison with 1998, the anomalous meridional circulation pattern in 2010 shifted northeastward, and then the western subtropical high, the mid-latitudinal trough and the northeastern Asia blocking high also shifted northeastward, causing intensified convergence of the cold and warm air masses at the southern region and thus more rainfall in the southwestern region and less in the northwestern region. In 1998, the anomalous cyclone, one component of the meridional pattern, located at the Songhuajiang-Nengjiang River basin, resulted in more rainfall in the majority of the area. The results of observation and the model show that the difference in SSTA in Kuroshio and its extension under the background of different El Ni觡o events is the key point:(1) The anomalous warmth moved westward from the mid-Pacific to the east of the Philippine Sea during the central event, which led the heat resources shifting to the northeast in 2010; subsequently, a shift occurred to the north of the anomalous ascent and decent, followed by a warm SSTA in the region of Kuroshio's extension in 2010 and Kuroshio in 1998.(2) The warm SSTA in the Kuroshio extension causing the Rossby wave activity flux strengthened in 2010, and then the westerly jet shifted northward and extended eastward. A warm SSTA in Kuroshio and cold SSTA in its extension in 1998 caused the westerly jet to shift southward and weaken. As a result,the anomalous anticyclone and cyclone shifted northward in 2010, and the blocking high also shifted northward.  相似文献   

17.
Understanding potential future influence of environmental, economic, and social drivers on land-use and sustainability is critical for guiding strategic decisions that can help nations adapt to change, anticipate opportunities, and cope with surprises. Using the Land-Use Trade-Offs (LUTO) model, we undertook a comprehensive, detailed, integrated, and quantitative scenario analysis of land-use and sustainability for Australia’s agricultural land from 2013–2050, under interacting global change and domestic policies, and considering key uncertainties. We assessed land use competition between multiple land-uses and assessed the sustainability of economic returns and ecosystem services at high spatial (1.1 km grid cells) and temporal (annual) resolution. We found substantial potential for land-use transition from agriculture to carbon plantings, environmental plantings, and biofuels cropping under certain scenarios, with impacts on the sustainability of economic returns and ecosystem services including food/fibre production, emissions abatement, water resource use, biodiversity services, and energy production. However, the type, magnitude, timing, and location of land-use responses and their impacts were highly dependent on scenario parameter assumptions including global outlook and emissions abatement effort, domestic land-use policy settings, land-use change adoption behaviour, productivity growth, and capacity constraints. With strong global abatement incentives complemented by biodiversity-focussed domestic land-use policy, land-use responses can substantially increase and diversify economic returns to land and produce a much wider range of ecosystem services such as emissions abatement, biodiversity, and energy, without major impacts on agricultural production. However, better governance is needed for managing potentially significant water resource impacts. The results have wide-ranging implications for land-use and sustainability policy and governance at global and domestic scales and can inform strategic thinking and decision-making about land-use and sustainability in Australia. A comprehensive and freely available 26 GB data pack (http://doi.org/10.4225/08/5604A2E8A00CC) provides a unique resource for further research. As similarly nuanced transformational change is also possible elsewhere, our template for comprehensive, integrated, quantitative, and high resolution scenario analysis can support other nations in strategic thinking and decision-making to prepare for an uncertain future.  相似文献   

18.
19.
Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds(VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin,China during the Ha Chi(Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected,and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area(36%) was much higher than that at the urban area(16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas.  相似文献   

20.
气候变化对中国东部季风区水资源脆弱性的影响评价   总被引:3,自引:0,他引:3  
将耦合暴露度、灾害风险、敏感性与抗压性的脆弱性评估模型应用于中国东部季风区水资源脆弱性评价,从水资源供需平衡角度分析了气候变化对东部季风区水资源脆弱性的影响。结果表明,2000年气候条件下,我国东部季风区接近90%的区域水资源处于中度脆弱及以上状态。其中水资源中度和高度脆弱区域约占全区的75%,极端脆弱区域接近15%。中国北方海河、黄河、淮河和辽河流域的水资源脆弱性最高。未来气候变化影响将加剧水资源脆弱性的风险,不同RCP排放情景下2030年代我国东部季风区水资源中度脆弱及以上区域面积有明显的扩大,极端脆弱区域将达到20%~25%。由于未来需水的进一步增加,中国北方水资源脆弱性的格局并未发生根本变化,而南方东南诸河等区域将面临可能发生的水危机。  相似文献   

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