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1.
基于1980—2015年6—8月CWRF模式（Climate-Weather Research and Forecasting model）14种方案的模拟结果和全国逐日降水观测资料,对比了Q-lin,Q-tri,RQ-lin,RQ-tri,SSP-lin和CDFt 6种误差订正方法对CWRF模式控制化方案（C1）模拟中国东部夏季日极端降水的订正效果,以CWRF模式14种方案日极端降水的模拟效果排名为基础,对比了模拟效果较好的4种方案集合、模拟较差的4种方案集合以及14种方案集合的订正效果,选出相对较好的订正方案进一步评估其成员集合后订正和成员分别订正后再集合的订正效果,结果表明:采用6种误差订正方法均可明显减少日极端降水模拟误差,其中RQ-lin方法订正效果最佳。CWRF模式对中国东部的极端降水指数均表现出较好的模拟能力,不同参数化集合方案得到14种方案成员先订正再集合与观测日极端降水平均值最为接近,研究结果对于改进模拟结果、提高其预测能力有重要应用价值。 相似文献
2.
NCAR RegCM2对东亚区域气候的模拟试验 总被引：39，自引：3，他引：39
利用垂直、水平高分辨率的区域气候模式ＮＣＡＲＲｅｇＣＭ２（１９９６年５月最新版本）进行了１９９１年夏季（５～８月）东亚洪涝个例的区域气候数值模拟．与观测事实的比较表明，该模式能够较好地再现出该个例我国江淮流域—日本季风降水的主要时空特征和环流形势异常等．也指出了模拟结果的一些不足之处和今后的改进方向 相似文献
3.
利用三峡库区降水观测资料和NCEP/NCAR再分析资料,分析了1980—2007年三峡库区洪涝年际变化特征,研究了三峡库区洪涝典型年份大尺度环流合成特征,进一步讨论了水汽输送特征。近年来,三峡库区年均洪涝、区域洪涝强度变化趋势不明显,而区域性洪涝较为频繁;乌拉尔山高压脊加强,经向环流增强,引导冷空气南下,与低纬北上暖湿气流交汇,三峡库区在以上环流背景下,易于产生洪涝灾害;蒙古高原,以及我国东北地区的环流背景合成有差异,三峡库区建库前典型洪涝年份较建库后环流异常更有利于降水;水汽输送异常在三峡地区均有汇合,建库前指示特征比三峡建库后大;典型洪涝年2004、2007年以及典型洪涝事件中,各个关键区水汽输送强度较弱。 相似文献
4.
影响东亚夏季风降水异常的前期海温信号 总被引：1，自引：3，他引：1
采用NCEP/NCAR大气再分析资料、HadISST海温数据以及中国东亚季风区的实测降水资料,探讨前期冬季海温与东亚夏季风之间的关系。研究表明,影响东亚夏季风异常的海温变化存在2个关键区,分别位于南印度洋中部和北太平洋东部,关键区的海温与东亚季风区的降水在长江中游有显著正相关,与东亚夏季风指数有显著负相关。基于此,定义了印-太海温指数。强海温指数年的南亚高压、索马里越赤道气流、西太平洋副高偏强,有利于东亚夏季风北进,中国大部降水偏多;弱海温指数年则相反。 相似文献
5.
基于1980—2016年长江流域站点观测降水,评估了CWRF区域气候模式对长江流域面雨量和极端降水气候事件的模拟能力.结果表明:CWRF模式能较好地再现1980—2016年长江流域及不同分区降水空间分布及月/季面雨量年际变率,且在冬、春季表现较好,夏、秋季次之.CWRF模式对长江流域面雨量存在系统性高估,对面雨量的模拟... 相似文献
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7.
区域气候模式侧边界的处理对东亚夏季风降水模拟的影响 总被引：27，自引：3，他引：24
在区域气候模式模拟中,侧边界的作用是引入大尺度强迫场。如何处理好侧边界,即大尺度强迫场和区域气候模式本身之间的关系问题,对于区域气候模式模拟和预报东亚夏季风降水具有重要意义。本文利用美国纽约州立大学Albany分校的区域气候模式（SUNYA-ReCM）,设计了两种不同的侧边界处理方法,来探讨侧边界对东亚夏季风降水模拟的影响。驱动区域模式的大尺度强迫场来自欧洲中期天气预报中心（ECMWF）及热带海洋大气研究计划（TOGA）的分析资料场。试验结果表明:（1）当模式的区域较大时,采用较小的侧边界缓冲区会在缓冲区与模式内部的交界处产生不连续;扩大缓冲区并且考虑不同尺度强迫在垂直方向上的不同作用,可以避免这一缺陷。（2）更重要的是采用后一种方案,即减少了区域气候模式在模拟大尺度环流场方面所起的作用,使得模式更多地依赖侧边界来得到更真实的、对东亚夏季风降水起重大影响的一些气流,如副高、西南季风和南海季风,对东亚夏季风降水无论是在大小上还是在雨带位置的演变上都能进行更好的模拟。 相似文献
8.
利用CWRF模式(Climate-Weather Research and Forecasting model)对国家气候中心BCC＿CSM1.1m业务预测模式短期气候预测结果进行中国区域降尺度,并使用1991—2010年3—8月逐日气温降水观测数据评估预测能力。结果表明：CWRF预测地面2 m气温、降水气候平均态的空间分布比BCC＿CSM1.1m更接近观测,分布误差更小;在保持总体技巧不低于BCC＿CSM1.1m的同时,CWRF对我国华东和华中地区的降水年际变化预测准确率更高;对不同强度的降水预测CWRF表现均优于BCC＿CSM1.1 m模式,尤其在极端降水预测准确率上更优。总之,得益于更高的空间分辨率和优化的低空物理过程模拟,CWRF降尺度可以提高中国夏季跨季度降水预测能力。 相似文献
9.
10.
论区域气候模式与全球模式嵌套时边界区的选择 总被引：8，自引：1，他引：7
做了3个试验,第一个试验只用大气环流模式(GCM),主要考察GCM的性能并确定其误差的区域分布.后两个为对比试验,一个试验中,将区域气候模式(RCM)(NjU-RCM)的侧边界放在全球模式(L9R15)中我们感兴趣的区域,未考虑侧边界区GCM的误差大小,另一个试验中,RCM的侧边界位置根据GCM预报误差的空间分布选取,使其落在GCM预报误差较小的区域.3个试验都对1998年5、6、7月份中国区域的降水过程进行了模拟和比较.结果表明:单独使用GCM的效果最差;当用GCM-RCM嵌套模式对区域气候进行预测时,GCM侧边界值的误差对RCM的模拟结果有显著的影响,嵌套侧边界若选择在GCM系统性误差较小的地区,模拟或预测效果会有明显的改进. 相似文献
11.
Anji Seth Sara A. Rauscher Suzana J. Camargo Jian-Hua Qian J. S. Pal 《Climate Dynamics》2007,28(5):461-480
To enable downscaling of seasonal prediction and climate change scenarios, long-term baseline regional climatologies which
employ global model forcing are needed for South America. As a first step in this process, this work examines climatological
integrations with a regional climate model using a continental scale domain nested in both reanalysis data and multiple realizations
of an atmospheric general circulation model (GCM). The analysis presents an evaluation of the nested model simulated large
scale circulation, mean annual cycle and interannual variability which is compared against observational estimates and also
with the driving GCM for the Northeast, Amazon, Monsoon and Southeast regions of South America. Results indicate that the
regional climate model simulates the annual cycle of precipitation well in the Northeast region and Monsoon regions; it exhibits
a dry bias during winter (July–September) in the Southeast, and simulates a semi-annual cycle with a dry bias in summer (December–February)
in the Amazon region. There is little difference in the annual cycle between the GCM and renalyses driven simulations, however,
substantial differences are seen in the interannual variability. Despite the biases in the annual cycle, the regional model
captures much of the interannual variability observed in the Northeast, Southeast and Amazon regions. In the Monsoon region,
where remote influences are weak, the regional model improves upon the GCM, though neither show substantial predictability.
We conclude that in regions where remote influences are strong and the global model performs well it is difficult for the
regional model to improve the large scale climatological features, indeed the regional model may degrade the simulation. Where
remote forcing is weak and local processes dominate, there is some potential for the regional model to add value. This, however,
will require improvments in physical parameterizations for high resolution tropical simulations. 相似文献
12.
利用1980—2015年6—8月我国逐日降水观测数据评估CWRF模式（Climate-Weather Research and Forecasting model）多种参数化方案对我国夏季日降水的模拟能力,并考察累积概率变换偏差订正法（CDFt）的订正效果。通过将广义帕累托分布（GPD）引入到偏差订正模型中,提出针对极端降水的累积概率变换偏差订正法（XCDFt）,检验和评估其对极端降水订正的适用性。结果显示:CWRF模式微物理过程选用Morrison-aerosol参数化方案组合对我国降水场的模拟较好,CDFt订正效果良好;XCDFt偏差订正模型能够较好地提取模式建模与验证时期变化信号,订正后相比订正前与观测极端降水的概率分布更为接近;经过XCDFt订正后华南、华中和华北地区20年一遇的极端降水重现水平较模拟值更接近观测值,可为CWRF模式提高极端降水的业务预测水平提供参考。 相似文献
13.
基于中国均一化气温数据集CN05.1的观测数据,结合暖昼指数（TX90）、冷昼指数（TX10）、暖夜指数（TN90）、冷夜指数（TN10）、暖日持续指数（WSDI）和冷日持续指数（CSDI）6个极端温度指数,从气候平均、概率分布、年际变率和年际趋势方面,系统评估区域气候模式（Climate–Weather Research and Forecasting model, CWRF）对1980～2015年间我国极端温度指数区域分布和年际变化的模拟能力,为改进并利用模式研究我国未来区域极端温度的预测提供科学依据。结果显示:观测的冷暖指数在北方的年际变率幅度高于南方,其中暖指数在我国大部分地区为增暖趋势,冷指数在北方地区的变冷趋势显著,尤其暖夜增暖、冷夜变冷,极端暖事件（WSDI）的持续性比冷事件（CSDI）显著。CWRF模式较好再现了极端温度指数的年均分布和年际变化趋势特征,尤其对暖日和冷日持续指数的模拟优势显著,但仍存在系统性的区域偏差,如低估暖昼和冷夜的极值强度;对华东地区暖（冷）指数变暖（冷）的趋势存在低（高）估;尤其是低估青藏高原地区暖、冷指数的强度,并且高估其暖昼变冷、暖夜变暖的年际变化趋势。因此,该模式对华东及高原地区极端温度的强度和年际变率的模拟仍亟需改善。 相似文献
14.
土壤湿度影响中国夏季气候的数值试验 总被引：10，自引：0，他引：10
利用"全球土壤湿度计划第2阶段"提供的土壤湿度资料强迫区域气候模式RegCM3,通过数值试验讨论了土壤湿度对东亚夏季气候模拟效果的影响。结果表明,合理考虑土壤湿度的作用,能够提高区域气候模式对中国夏季降水和2 m气温的空间分布型及逐日变化的模拟效果;模拟结果与观测的相关分析显示,降水和2 m气温的年际变化都得到了有效改进,这种改进在气温上尤为明显。不过上述改进具有区域依赖性。数值试验结果表明,气温对土壤湿度的敏感性强于降水,这也从一个侧面说明提高降水模拟效果的难度。总体而言,合理的土壤湿度能够提高区域气候模式对中国夏季气候的模拟能力。因此,合理描述土壤湿度的变化,是提高中国夏季气候预报技巧的潜在途径之一。 相似文献
15.
Indices for temperature and precipitation extremes are calculated on the basis of the global climate model ECHAM5/MPI-OM simulations
of the twentieth century and SRES A1B and B1 emission scenarios for the twenty-first century. For model evaluation, the simulated
indices representing the present climate were compared with indices based on observational data. This comparison shows that
the model is able to realistically capture the observed climatological large-scale patterns of temperature and precipitation
indices, although the quality of the simulations depends on the index and region under consideration. In the climate projections
for the twenty-first century, all considered temperature-based indices, minimum Tmin, maximum Tmax, and the frequency of tropical
nights, show a significant increase worldwide. Similarly, extreme precipitation, as represented by the maximum 5-day precipitation
and the 95th percentile of precipitation, is projected to increase significantly in most regions of the world, especially
in those that are relatively wet already under present climate conditions. Analogously, dry spells increase particularly in
those regions that are characterized by dry conditions in present-day climate. Future changes in the indices exhibit distinct
regional and seasonal patterns as identified exemplarily in three European regions. 相似文献
16.
误差订正是提高模式模拟和预报性能的有效方法。基于CWRF(regional Climate-Weather Research and Forecasting model)25套不同物理参数化方案的日降水量模拟资料, 对比仅进行降水日数订正(OCD)、仅进行降水量订正(OCM)和先订正降水日数再订正降水量(COR)三种订正方法, 先订正再等权重集成和先等权重集成再订正两种订正思路, 重点对1997—2015年华中和华南地区夏季日降水进行订正效果的对比。结果表明:(1)降水日的订正是必要的, 综合而言COR方法对CWRF模式日降水的订正效果更佳, 尤其是小量级降水, 但降水强度的表现不如OCM; (2)先集成后订正的效果更好; (3) CWRF模式不同参数化方案对日降水的模拟能力有显著差别, 经过订正后模拟能力均有所提升, 但对于不同的模拟方案, 其订正效果也不同。表明, 误差订正确实能有效提高模式模拟及预报性能, 但其效果存在不确定性。提高模式的预报性能, 关键还是提高模式对真实大气动力学的表述能力。 相似文献
17.
尽管气候变化是全球性的现象,但其表现和结果随区域不同而不同,因此区域气候信息对于气候变化的作用和风险评估很重要。基于此,IPCC第六次评估报告（AR6）第一工作组（WGI）报告第十章对如何从全球链接到区域气候变化方面进行了评估。区域气候变化是对自然强迫和人类活动的区域响应、对大尺度气候系统内部变率的响应和区域气候本身反馈过程的相互作用结果。因此,本章重点关注如何从多套观测资料,不同模式的集合,物理过程的理解、专家判断和本地信息等多元信息中有效提炼出区域信息的方法。通过提炼方法指出人类活动是许多次大陆尺度上1950年代以来区域平均温度变化的主要驱动力,但参考时段和阈值的选择对人类活动信号是否出现和出现的早晚有影响。人类活动对一些区域的多年代际降水变化有一定贡献,但其不确定性相对全球平均而言更大。气候系统内部变率可以在很大程度上延迟和阻碍人类活动信号在区域气候变化中的出现。区域气候变化的评估给决策者提供了更多有用的信息,增加了评估报告的适用性。 相似文献
18.
Sources of systematic errors in the climatology of a regional climate model over Europe 总被引：2，自引：2，他引：0
Two ten-year simulations made with a European regional climate model (RCM) are compared. They are driven by the same observed
sea surface temperatures but use different lateral boundary forcing. For one simulation, RCM AMIP, this forcing is obtained
from a standard integration of a global general circulation model (GCM AMIP), whereas for the other simulation, RCM ASSIM,
it is derived from a time series of operational analyses. The archive of analysis fields (surface pressure plus winds and
temperatures on various pressure levels) is not sufficiently comprehensive to provide directly the full set of driving fields
required for the RCM (in particular, no moisture fields are present), so these are obtained via a GCM integration, GCM ASSIM,
in which the model is continuously relaxed towards the analysis fields using a data assimilation technique. Errors in RCM
AMIP can arise either from the internal RCM physics or from errors in the lateral boundary forcing inherited from GCM AMIP.
Errors in RCM ASSIM can arise from the internal RCM physics or the boundary moisture forcing but not from the driving circulation.
Although previous studies have considered RCM integrations driven either by output from standard GCM integrations or operational
analyses, our study is the first to compare parallel integrations of each type. This allows the total systematic error in
an RCM integration driven by standard GCM output to be partitioned into components arising from the driving circulation and
the internal RCM physics. These components indicate the scope for reducing regional simulation biases by improving either
the driving GCM or the RCM itself. The results relate mainly to elements of surface climate likely to be influenced by both
the driving circulation and regional physical processes operating in the RCM. For cloud cover, errors are found to arise largely
from the internal RCM physics. Values are too low despite a positive relative humidity bias, indicating shortcomings in the
parametrisation scheme used to calculate cloud cover. In summer, surface temperature and precipitation errors are also explained
principally by regional processes. For example excessive solar heating leads to anomalously high surface temperatures over
southern Europe and excessive drying of the soil reduces precipitation in the south eastern sector of the domain. The lateral
boundary forcing reduces precipitation in the south eastern sector of the domain. The lateral boundary forcing also exerts
some influence, mainly via a tropospheric cold bias which partially offsets the warming over southern Europe and also increases
precipitation. In other seasons the lateral boundary forcing and the regional physics both contribute significantly to the
errors in surface temperature and precipitation. In winter the boundary forcing (apart from moisture) is responsible for about
60% of the total error variance for temperature and about 40% for precipitation, due to the cold bias and circulation errors
such as a southward shift in the storm track. The remaining errors arise from the regional physics, although for precipitation
an excessive supply of moisture from the lateral boundaries also contributes. The skill of the mesoscale component of the
surface temperature and precipitation distributions exceeds previous estimates, due to more realistic observed climatology.
The mesoscale patterns are very similar in the two RCM simulations indicating that errors in the simulation of fine scale
detail arise mainly from inadequate representations of local forcings rather than errors in the large-scale circulation. Circulation
errors in RCM AMIP (e.g. cold bias, southward shift of storm track) are also present in GCM AMIP, but are largely absent in
RCM ASSIM except in summer. This confirms evidence from previous work that the key to reducing most circulation errors in
the RCM lies in improving the driving GCM. Regional processes only make a major contribution to circulation errors in summer,
when reduced advection from the boundaries allows errors in surface temperature to be transmitted more effectively into the
troposphere. Finally, we find evidence of error balances in the GCM which act to minimise biases in important climatological
variables. This reflects tuning of the model physics at GCM resolution. In order to achieve simultaneous optimisation of the
RCM and GCM at widely differing resolutions it may be necessary to introduce explicit scale dependences into some aspects
of the physics.
Received: 17 September 1997/Accepted: 10 March 1998 相似文献