共查询到20条相似文献，搜索用时 22 毫秒
1.
E. García-Bustamante J. F. González-Rouco J. Navarro E. Xoplaki J. Luterbacher P. A. Jiménez J. P. Montávez A. Hidalgo E. E. Lucio-Eceiza 《Climate Dynamics》2013,40(3-4):935-949
The wind power generated during winter months 1999–2003 at several wind farms in the northeastern Iberian Peninsula is investigated through the application of a statistical downscaling. This allows for an improved understanding of the wind power variability and its relationship to the large scale atmospheric circulation. It is found that 97 % of the variability of this non-climatic variable is connected to changes in the atmospheric circulation. The methodological uncertainty associated with multiple configurations of the statistical downscaling method replicates well the observed variability of the wind power, an indication of the robustness of the methodology to changes in the model set up. In addition, the use of the statistical model is extended out of the observational period providing an estimation of the long-term variability of wind power throughout the twentieth century. The extended wind power reconstruction shows large inter-annual and multidecadal variability. Alternative approaches to calibrate the empirical downscaling model using actual wind power observations have also been investigated. They involve the estimation of wind power changes from downscaled wind values and make use of several transfer functions based on the linearity between wind and wind energy. The performance of the latter approaches is similar to the direct downscaling of wind power and may allow wind power production estimations even in the absence of historical wind turbine records. These results can be of great interest for deriving medium/long term impact-oriented energy assessments, especially when wind power observations are missing as well as in the context of climate change scenarios. 相似文献
2.
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
3.
4.
复杂地形导致近地层风场时空变化大,是影响风电场短期风电功率预测准确率的重要因素。为此,基于中尺度数值预报模式和微尺度计算流体力学模式,建立了风电场短期风电功率动力降尺度预测系统。该系统由中尺度数值预报模式、微尺度风场基础数据库、风电功率预测集成系统组成,能够预测复杂地形风电场中每台风电机组未来72 h逐15 min的发电量。提高了复杂地形风场发电功率预测准确率,同时还可以在上报电网的风电功率预测结果中考虑运行维护计划和限电等因素对实际并网功率的影响。2014年7月-2015年1月的业务预测试验表明,风电场短期风电功率动力降尺度预测系统的月预测相对误差均小于0.2,满足中国国家电网对风电功率预测误差和时效性的业务要求。动力降尺度技术不受具体项目地形复杂程度和历史观测数据样本量的限制,可以在新建风电场中推广应用,具备实际的可操作性。 相似文献
5.
This study investigated the simulations of three months of seasonal tropical cyclone (TC) activity over the western North Pacific using the Advanced Research WRF Model. In the control experiment (CTL), the TC frequency was considerably overestimated. Additionally, the tracks of some TCs tended to have larger radii of curvature and were shifted eastward. The large-scale environments of westerly monsoon flows and subtropical Pacific highs were unreasonably simulated. The overestimated frequency of TC formation was attributed to a strengthened westerly wind field in the southern quadrants of the TC center. In comparison with the experiment with the spectral nudging method, the strengthened wind speed was mainly modulated by large-scale flow that was greater than approximately 1000 km in the model domain. The spurious formation and undesirable tracks of TCs in the CTL were considerably improved by reproducing realistic large-scale atmospheric monsoon circulation with substantial adjustment between large-scale flow in the model domain and large-scale boundary forcing modified by the spectral nudging method. The realistic monsoon circulation took a vital role in simulating realistic TCs. It revealed that, in the downscaling from large-scale fields for regional climate simulations, scale interaction between model-generated regional features and forced large-scale fields should be considered, and spectral nudging is a desirable method in the downscaling method. 相似文献
6.
In this study, the spatial differences and interannual fluctuations in temporal variability of surface pressure and wind speed on different timescales at 12 locations in the Canadian Arctic are documented. Temporal variability is defined as the mean-squared value of time tendencies smoothed by running means over different intervals. It is shown that variability on timescales of up to 1 month is itself highly variable, both in space and time. Due to the significant impacts from the immediate geographical environment, for surface wind speed, these variations show no spatial pattern on a continental scale, and only a few persistent trends over periods of more than 10 years. Also, spatial and temporal anomalies do not significantly depend on timescale. Contrary to this, spatial and temporal variations in the variability of surface pressure and its changes with time show well-defined regional similarities, as well as a strong spatial and temporal dependence on timescale. As a result, variability of surface pressure on timescales between 1 and 3 days increases from the northeast region of the domain towards the southwest. On longer timescales, this spatial gradient is reversed. The consistent spatial pattern across the study domain suggests that variability of surface pressure is primarily governed by large-scale atmospheric processes, and is to a large extent independent of the exact geographical setting. 相似文献
7.
Emilie Vanvyve Nicholas Hall Christophe Messager Stéphanie Leroux Jean-Pascal van Ypersele 《Climate Dynamics》2008,30(2-3):191-202
Sensitivity studies with regional climate models are often performed on the basis of a few simulations for which the difference
is analysed and the statistical significance is often taken for granted. In this study we present some simple measures of
the confidence limits for these types of experiments by analysing the internal variability of a regional climate model run
over West Africa. Two 1-year long simulations, differing only in their initial conditions, are compared. The difference between
the two runs gives a measure of the internal variability of the model and an indication of which timescales are reliable for
analysis. The results are analysed for a range of timescales and spatial scales, and quantitative measures of the confidence
limits for regional model simulations are diagnosed for a selection of study areas for rainfall, low level temperature and
wind. As the averaging period or spatial scale is increased, the signal due to internal variability gets smaller and confidence
in the simulations increases. This occurs more rapidly for variations in precipitation, which appear essentially random, than
for dynamical variables, which show some organisation on larger scales. 相似文献
8.
K. Goubanova V. Echevin B. Dewitte F. Codron K. Takahashi P. Terray M. Vrac 《Climate Dynamics》2011,36(7-8):1365-1378
The key aspect of the ocean circulation off Peru?CChile is the wind-driven upwelling of deep, cold, nutrient-rich waters that promote a rich marine ecosystem. It has been suggested that global warming may be associated with an intensification of upwelling-favorable winds. However, the lack of high-resolution long-term observations has been a limitation for a quantitative analysis of this process. In this study, we use a statistical downscaling method to assess the regional impact of climate change on the sea-surface wind over the Peru?CChile upwelling region as simulated by the global coupled general circulation model IPSL-CM4. Taking advantage of the high-resolution QuikSCAT wind product and of the NCEP reanalysis data, a statistical model based on multiple linear regressions is built for the daily mean meridional and zonal wind at 10?m for the period 2000?C2008. The large-scale 10?m wind components and sea level pressure are used as regional circulation predictors. The skill of the downscaling method is assessed by comparing with the surface wind derived from the ERS satellite measurements, with in situ wind observations collected by ICOADS and through cross-validation. It is then applied to the outputs of the IPSL-CM4 model over stabilized periods of the pre-industrial, 2?×?CO2 and 4?×?CO2 IPCC climate scenarios. The results indicate that surface along-shore winds off central Chile (off central Peru) experience a significant intensification (weakening) during Austral winter (summer) in warmer climates. This is associated with a general decrease in intra-seasonal variability. 相似文献
9.
A multi-model ensemble approach for assessment of climate change impact on surface winds in France 总被引：2，自引：1，他引：1
Statistical downscaling of 14 coupled atmosphere-ocean general circulation models (AOGCM) is presented to assess potential
changes of the 10 m wind speeds in France. First, a statistical downscaling method is introduced to estimate daily mean 10 m
wind speed at specific sites using general circulation model output. Daily 850 hPa wind field has been selected as the large
scale circulation predictor. The method is based on a classification of the daily wind fields into a few synoptic weather
types and multiple linear regressions. Years are divided into an extended winter season from October to March and an extended
summer season from April to September, and the procedure is conducted separately for each season. ERA40 reanalysis and observed
station data have been used to build and validate the downscaling algorithm over France for the period 1974–2002. The method
is then applied to 14 AOGCMs of the coupled model intercomparison project phase 3 (CMIP3) multi-model dataset. Three time
periods are focused on: a historical period (1971–2000) from the climate of the twentieth century experiment and two climate
projection periods (2046–2065 and 2081–2100) from the IPCC SRES A1B experiment. Evolution of the 10 m wind speed in France
and associated uncertainties are discussed. Significant changes are depicted, in particular a decrease of the wind speed in
the Mediterranean area. Sources of those changes are investigated by quantifying the effects of changes in the weather type
occurrences, and modifications of the distribution of the days within the weather types. 相似文献
10.
The influence of synoptic airflow on UK daily precipitation extremes. Part I: Observed spatio-temporal relationships 总被引：1，自引：1，他引：0
We study the influence of synoptic scale atmospheric circulation on extreme daily precipitation across the United Kingdom, using observed time series from 689 rain gauges. To this end we employ a statistical model, that uses airflow strength, direction and vorticity as predictors for the generalised extreme value distribution of monthly precipitation maxima. The inferred relationships are connected with the dominant westerly flow, the orography, and the moisture supply from surrounding seas. We aggregated the results for individual rain gauges to regional scales to investigate the temporal variability of extreme precipitation. Airflow explains a significant fraction of the variability on subannual to decadal time scales. A large fraction of the especially heavy winter precipitation during the 1980s and 1990s in north Scotland can be attributed to a prevailing positive phase of the North Atlantic Oscillation. Our statistical model can be used for statistical downscaling and to validate regional climate model output. 相似文献
11.
Ralf Döscher Klaus Wyser H. E. Markus Meier Minwei Qian René Redler 《Climate Dynamics》2010,34(7-8):1157-1176
The relative importance of regional processes inside the Arctic climate system and the large scale atmospheric circulation for Arctic interannual climate variability has been estimated with the help of a regional Arctic coupled ocean-ice-atmosphere model. The study focuses on sea ice and surface climate during the 1980s and 1990s. Simulations agree reasonably well with observations. Correlations between the winter North Atlantic Oscillation index and the summer Arctic sea ice thickness and summer sea ice extent are found. Spread of sea ice extent within an ensemble of model runs can be associated with a surface pressure gradient between the Nordic Seas and the Kara Sea. Trends in the sea ice thickness field are widely significant and can formally be attributed to large scale forcing outside the Arctic model domain. Concerning predictability, results indicate that the variability generated by the external forcing is more important in most regions than the internally generated variability. However, both are in the same order of magnitude. Local areas such as the Northern Greenland coast together with Fram Straits and parts of the Greenland Sea show a strong importance of internally generated variability, which is associated with wind direction variability due to interaction with atmospheric dynamics on the Greenland ice sheet. High predictability of sea ice extent is supported by north-easterly winds from the Arctic Ocean to Scandinavia. 相似文献
12.
针对动力气候模式对区域或更小空间尺度内的日降水预测技巧偏低的问题,应用最优子集回归 (OSR) 方法对国家气候中心业务化的月动力气候模式 (DERF) 输出的高度场、风场和海平面气压场进行降尺度处理用于降水预测,旨在提高预测准确率。1982—2006年交叉检验结果表明:OSR方法能显著提高降水预测技巧,其中11~40 d改善效果最为显著。在此基础上,应用一步法和两步法两种统计降尺度方法预测极端降水日数,交叉检验结果表明:两种方法均优于随机预测,冬季两步法预测技巧略高于一步法,夏季一步法略优于两步法。综合认为OSR,OSR结合随机天气发生器 (WG) 两种统计降尺度方法对月尺度降水或极端降水日数的预测均具有较高的技巧,可作为短期气候预测的重要参考信息。 相似文献
13.
The Mediterranean region is identified as one of the two main hot-spots of climate change and also known to have the highest concentration of cyclones in the world. These atmospheric features contribute significantly to the regional climate but they are not reproduced by the Atmosphere–Ocean General Circulation Models (AOGCM), due to their coarse horizontal resolution, which have recently been run in the frame of the 5th Climate Model Intercomparison Project. This article investigates the benefit of dynamically downscaling the Institut Pierre Simon Laplace (IPSL) AOGCM (IPSL-CM5) historical simulation by the weather and research forecasting (WRF) for the representation of the Mediterranean surface winds and cyclonic activity. Indeed, when considering IPSL-CM5 atmospheric fields, the dramatic underestimation of the cyclonic activity in the most cyclogenetic region of the world jeopardizes our ability to investigate in-depth the Mediterranean regional climate and trend in the context of global change. The WRF model shows remarkable skill to reproduce regional cyclogenesis. Indeed, cyclones occurrence is quasi-absent in IPSL-CM5 data but when applying dynamical downscaling their spatial–temporal variability is very close to the re-analysis. This is a clear benefit of dynamical downscaling in regions of strong topographic forcing. This “steady” source of forcing allows the production of lee cyclogenesis and the development of strong cyclones, whatever the quality of the large-scale circulation provided at the WRF’s boundaries by IPSL-CM5. However, dynamical downscaling still presents disadvantages as for instance the fact that large-scale inaccurate features of the IPSL-CM5 regional circulation are replicated by WRF due to the boundary controlled (small domain) simulation. The advantages and disadvantages of dynamical downscaling are thoroughly discussed in this paper revealing its importance for climate research, especially in the context of future scenarios and wind impacts. 相似文献
14.
A. G. Nidheesh Matthieu Lengaigne Jérôme Vialard A. S. Unnikrishnan H. Dayan 《Climate Dynamics》2013,41(2):381-402
In this study, we analysed decadal and long-term steric sea level variations over 1966–2007 period in the Indo-Pacific sector, using an ocean general circulation model forced by reanalysis winds. The simulated steric sea level compares favourably with sea level from satellite altimetry and tide gauges at interannual and decadal timescales. The amplitude of decadal sea level variability (up to ~5 cm standard deviation) is typically nearly half of the interannual variations (up to ~10 cm) and two to three times larger than long-term sea level variations (up to 2 cm). Zonal wind stress varies at decadal timescales in the western Pacific and in the southern Indian Ocean, with coherent signals in ERA-40 (from which the model forcing is derived), NCEP, twentieth century and WASWind products. Contrary to the variability at interannual timescale, for which there is a tendency of El Niño and Indian Ocean Dipole events to co-occur, decadal wind stress variations are relatively independent in the two basins. In the Pacific, those wind stress variations drive Ekman pumping on either side of the equator, and induce low frequency sea level variations in the western Pacific through planetary wave propagation. The equatorial signal from the western Pacific travels southward to the west Australian coast through equatorial and coastal wave guides. In the Indian Ocean, decadal zonal wind stress variations induce sea level fluctuations in the eastern equatorial Indian Ocean and the Bay of Bengal, through equatorial and coastal wave-guides. Wind stress curl in the southern Indian Ocean drives decadal variability in the south-western Indian Ocean through planetary waves. Decadal sea level variations in the south–western Indian Ocean, in the eastern equatorial Indian Ocean and in the Bay of Bengal are weakly correlated to variability in the Pacific Ocean. Even though the wind variability is coherent among various wind products at decadal timescales, they show a large contrast in long-term wind stress changes, suggesting that long-term sea level changes from forced ocean models need to be interpreted with caution. 相似文献
15.
A statistical model to downscale local daily temperature extremes from synoptic-scale atmospheric circulation patterns in the Australian region 总被引：3，自引：0，他引：3
The study seeks to describe one method of deriving information about local daily temperature extremes from larger scale atmospheric
flow patterns using statistical tools. This is considered to be one step towards downscaling coarsely gridded climate data
from global climate models (GCMs) to finer spatial scales. Downscaling is necessary in order to bridge the spatial mismatch
between GCMs and climate impact models which need information on spatial scales that the GCMs cannot provide. The method of
statistical downscaling is based on physical interaction between atmospheric processes with different spatial scales, in this
case between synoptic scale mean sea level pressure (MSLP) fields and local temperature extremes at several stations in southeast
Australia. In this study it was found that most of the day-to-day spatial variability of the synoptic circulation over the
Australian region can be captured by six principal components. Using the scores of these PCs as multivariate indicators of
the circulation a substantial part of the local daily temperature variability could be explained. The inclusion of temperature
persistence noticeably improved the performance of the statistical model. The model established and tested with observations
is thought to be finally applied to GCM-simulated pressure fields in order to estimate pressure-related changes in local temperature
extremes under altered CO2 conditions.
Received: 26 March 1996 / Accepted: 20 September 1996 相似文献
16.
Arctic forcing of decadal variability in the tropical Pacific Ocean in a high-resolution global coupled GCM 总被引：1，自引：0，他引：1
Kristopher B. Karnauskas 《Climate Dynamics》2014,42(11-12):3375-3388
The hypothesis that northern high-latitude atmospheric variability influences decadal variability in the tropical Pacific Ocean by modulating the wind jet blowing over the Gulf of Tehuantepec (GT) is examined using the high-resolution configuration of the MIROC 3.2 global coupled model. The model is shown to have acceptable skill in replicating the spatial pattern, strength, seasonality, and time scale of observed GT wind events. The decadal variability of the simulated GT winds in a 100-year control integration is driven by the Arctic Oscillation (AO). The regional impacts of the GT winds include strong sea surface cooling, increased salinity, and the generation of westward-propagating anticyclonic eddies, also consistent with observations. However, significant nonlocal effects also emerge in concert with the low-frequency variability of the GT winds, including anomalously low upper ocean heat content (OHC) in the central tropical Pacific Ocean. It is suggested that the mesoscale eddies generated by the wind stress curl signature of the GT winds, which propagate several thousand kilometers toward the central Pacific, contribute to this anomaly by strengthening the meridional overturning associated with the northern subtropical cell. A parallel mechanism for the decadal OHC variability is considered by examining the Ekman and Sverdrup transports inferred from the atmospheric circulation anomalies in the northern midlatitude Pacific directly associated with the AO. 相似文献
17.
General circulation models still show deficiencies in simulating the basic features of the West African Monsoon at intraseasonal,
seasonal and interannual timescales. It is however, difficult to disentangle the remote versus regional factors that contribute
to such deficiencies, and to diagnose their possible consequences for the simulation of the global atmospheric variability.
The aim of the present study is to address these questions using the so-called grid point nudging technique, where prognostic
atmospheric fields are relaxed either inside or outside the West African Monsoon region toward the ERA40 reanalysis. This
regional or quasi-global nudging is tested in ensembles of boreal summer simulations. The impact is evaluated first on the
model climatology, then on intraseasonal timescales with an emphasis on North Atlantic/Europe weather regimes, and finally
on interannual timescales. Results show that systematic biases in the model climatology over West Africa are mostly of regional
origin and have a limited impact outside the domain. A clear impact is found however on the eddy component of the extratropical
circulation, in particular over the North Atlantic/European sector. At intraseasonal timescale, the main regional biases also
resist to the quasi-global nudging though their magnitude is reduced. Conversely, nudging the model over West Africa exerts
a strong impact on the frequency of the two North Atlantic weather regimes that favor the occurrence of heat waves over Europe.
Significant impacts are also found at interannual timescale. Not surprisingly, the quasi-global nudging allows the model to
capture the variability of large-scale dynamical monsoon indices, but exerts a weaker control on rainfall variability suggesting
the additional contribution of regional processes. Conversely, nudging the model toward West Africa suppresses the spurious
ENSO teleconnection that is simulated over Europe in the control experiment, thereby emphasizing the relevance of a realistic
West African monsoon simulation for seasonal prediction in the extratropics. Further experiments will be devoted to case studies
aiming at a better understanding of regional processes governing the monsoon variability and of the possible monsoon teleconnections,
especially over Europe. 相似文献
18.
An Improved Statistical-Dynamical Downscaling Scheme and its Application to the Alpine Precipitation Climatology 总被引：1，自引：1，他引：0
Summary An improved statistical-dynamical downscaling method for the regionalization of large-scale climate analyses or simulations
is introduced. The method is based on the disaggregation of a multi-year time-series of large-scale meteorological data into
multi-day episodes of quasi-stationary circulation. The episodes are subsequently grouped into a defined number of classes.
A regional model is used to simulate the evolution of weather during the most typical episode of each class. These simulations
consider the effects of the regional topography. Finally, the regional model results are statistically weighted with the climatological
frequencies of the respective circulation classes in order to provide regional climate patterns.
The statistical-dynamical downscaling procedure is applied to large-scale analyses for a 12-year climate period 1981–1992.
The performance of the new method is demonstrated for winter precipitation in the Alpine region. With the help of daily precipitation
analyses it was possible to validate the results and to assess the different sources of errors. It appeared that the main
error originates from the regional model, whereas the error of the procedure itself was relatively unimportant.
This new statistical-dynamical downscaling method turned out to be an efficient alternative to the commonly used method of
nesting a regional model continuously within a general circulation model (dynamical downscaling).
Received April 8, 1999 Revised July 30, 1999 相似文献
19.
20.
基于山东省123个国家级气象观测站1961—2015年夏季降水资料、1991—2015年NCEP再分析资料,分析了山东夏季降水变化特征及其与大气环流的关系。结果表明,在山东夏季降水偏多（少）时,乌拉尔山阻塞高压偏弱（强）,副热带高压偏强（弱）,南亚高压偏强（弱）,并且200 hPa经向风场有明显的类似丝绸之路遥相关型的波列结构。利用国家气候中心第二代海气耦合模式3月起报的未来夏季海平面气压场建立降尺度预测模型,该模型对山东夏季降水的预测符号一致率达到64%,有一定的预测能力,进一步分析发现,模式对关键区环流因子的模拟预测能力显著影响降尺度预测方法的准确率。 相似文献