共查询到20条相似文献，搜索用时 31 毫秒
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基于多源的气温月值资料,在数据整合和初步质量控制基础上,同时采用标准化序列法和多元线性回归法对河北保定气象站1913-2014 年月平均气温、最高气温和最低气温资料进行了插补。通过交叉检验法分析发现,标准化序列法插补得到的气温序列效果较好,并且气候统计特征与同区域周边站的研究结果更具一致性。利用惩罚最大F 检验（PMF）对插补后序列的均一性进行了检验,结果表明：通过插补得到的保定站百年气温月值序列的均一性相对较好,仅月平均最低气温序列存在2 个显著间断点,分别由同类型仪器的更换和台站迁移导致,研究中采用分位数匹配（QM）对其进行了订正,建立了保定站百年气温月值序列。通过与邻近单站及我国中东部区域均一化百年气温序列的综合对比显示,本文建立的保定站百年气温月值序列与邻近单站的相关性基本达到0.8 以上;从增暖趋势来看,保定站与中东部区域平均序列分别达0.121 ℃/10a、0.204 ℃/10a,基本在同一量级内：这一定程度上说明建立的保定站百年气温序列相对合理。 相似文献
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In near-calm conditions it is difficult to make direct measurements of atmospheric advection reliably and cheaply, particularly at many points over a large area. An alternative indirect method is examined using time-series measurements of atmospheric temperature (or any other convenient conserved field variable) at points on a spatial grid.System identification methodology is applied to analyze atmospheric temperature data obtained in such near-calm conditions during an experiment with a low-flying helicopter. A three-parameter numerical model of atmospheric advection has been identified in the temperature data, the advection parameters being an eddy diffusion coefficient and horizontal components of the wind velocity. It has been demonstrated by analysis of all the assumptions, and using simulated data, that in this case the standard least-square procedure can be applied to recover sensible parameter estimates, even though the model is of the error-in-variables type and parameters appear to change abruptly at certain moments of time (but by a reasonably small amount). The parameter estimates have been validated against independent data. 相似文献
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Maurizio Maugeri Letizia Buffoni Barbara Delmonte Adriana Fassina 《Climatic change》2002,53(1-3):119-149
Daily meteorological observations have been made at the Brera astronomical observatory in Milan since 1763. Even if the data have always been collected at this observatory, the Milan series are far from being homogeneous as several changes were made to instruments, station location and observation methods. Within this context, the purpose of the paper is to discuss data homogenisation. Homogenisation is based both on objective information extracted from the station history (direct methodology) and on some statistical estimates (indirect methodology). Homogenisation by indirect methodology is mainly performed by comparison with other series whereas, if no other homogeneous series are available, it is based on the hypothesis that some statistics, such as the daily temperature range or the day to day variability, have no significant trends within some selected periods. Besides homogenisation also the completion of the series is discussed. Theresulting series are complete and homogenised daily minimum, mean and maximum temperatures and complete and homogenised daily mean pressures. They all cover the period 1763–1998. 相似文献
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A new approach for rigorous spatial analysis of the downscaling performance of regional climate model (RCM) simulations is introduced. It is based on a multiple comparison of the local tests at the grid cells and is also known as “field” or “global” significance. New performance measures for estimating the added value of downscaled data relative to the large-scale forcing fields are developed. The methodology is exemplarily applied to a standard EURO-CORDEX hindcast simulation with the Weather Research and Forecasting (WRF) model coupled with the land surface model NOAH at 0.11 ° grid resolution. Monthly temperature climatology for the 1990–2009 period is analysed for Germany for winter and summer in comparison with high-resolution gridded observations from the German Weather Service. The field significance test controls the proportion of falsely rejected local tests in a meaningful way and is robust to spatial dependence. Hence, the spatial patterns of the statistically significant local tests are also meaningful. We interpret them from a process-oriented perspective. In winter and in most regions in summer, the downscaled distributions are statistically indistinguishable from the observed ones. A systematic cold summer bias occurs in deep river valleys due to overestimated elevations, in coastal areas due probably to enhanced sea breeze circulation, and over large lakes due to the interpolation of water temperatures. Urban areas in concave topography forms have a warm summer bias due to the strong heat islands, not reflected in the observations. WRF-NOAH generates appropriate fine-scale features in the monthly temperature field over regions of complex topography, but over spatially homogeneous areas even small biases can lead to significant deteriorations relative to the driving reanalysis. As the added value of global climate model (GCM)-driven simulations cannot be smaller than this perfect-boundary estimate, this work demonstrates in a rigorous manner the clear additional value of dynamical downscaling over global climate simulations. The evaluation methodology has a broad spectrum of applicability as it is distribution-free, robust to spatial dependence, and accounts for time series structure. 相似文献
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An analogue-based method to downscale surface air temperature: application for Australia 总被引：1，自引：0，他引：1
A statistical model (SM) has been developed to downscale large-scale predictors given by general circulation models (GCMs);
emphasis has been put on local surface air temperature in two areas of interest: the south-west corner (SWC) of Western Australia
and the Murray-Darling Basin (MDB) in southeastern Australia. This is a complementary approach to the dynamical modelling
of climate change using high-resolution nested regional models. The analogue technique was chosen for this study as it has
proven successful in the past for mid-latitude climate and, in particular, for forecasting in Australia. Furthermore, the
analogue technique is successful in reproducing spells of anomalous events. The development and validation datasets used for
both predictors and predictants cover the 1970–1993 period. Predictors are extracted from a dataset of operational analyses
for the Australian region. Several predictors have been assessed alone and combined. Mean sea level pressure and temperature
at 850 hPa have been identified as the most useful combination. Predictants have come from quality controlled stations with
daily temperature extremes for the 1970–1993 period. Twenty two stations in the SWC and 29 in the MDB have been selected.
The sensitivity of the SM has been tested to several internal parameters. The number of atmospheric predictors and the geographical
domain on which large-scale fields are used are key factors that maximise the skill of the SM. Several metrics have been tested
taking into account the state of the predictors on the day or, in order to describe the evolution of the atmosphere, over
several days. This latter has been particularly useful in improving the representation of anomalous spells as it partially
incorporates the auto-correlation of surface temperature. The correlation obtained between the observed local temperature
series and the reconstructed series ranges between 0.5 and 0.8. Best results are obtained in summer and for maximum temperature.
The reproduction of spells is satisfactory for most stations. The SM is then applied to large-scale fields obtained from a
GCM forced by observed sea surface temperature; the improvement gained when using the SM instead of relying on the surface
temperature calculated by the GCM is shown.
Received: 14 December 1999 / Accepted: 10 January 2001 相似文献
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The aim of this work is assessment of regional atmospheric influence on satellite derivation of Adriatic Sea surface temperature (SST). To this end the European Centre for Medium-Range Weather Forecast (ECMWF) ERA-40 reanalysis dataset has been employed to provide the temperature and humidity profiles and surface data, while the RTTOV 8.7 radiative transfer model was used to calculate the top-of-atmosphere brightness temperatures for the advanced very high-resolution radiometer (AVHRR) channels. Ten ERA-40 grid points over the Adriatic Sea were used in the analysis, providing 29,590, 00 UTC and 12 UTC, clear-sky profiles. Climatological analysis of the ERA-40 profiles demonstrated distinct seasonal variability over the Adriatic Sea. Seasonality noted in the temperature and specific humidity profiles also evinced in the atmospheric transmittance, thermal channels temperature deficit, and derived γ and ρ parameters. A multivariate analysis was applied to relate the simulated top-of-atmosphere brightness temperatures to the Adriatic SSTs in order to generate exploratory sets of SST retrieval coefficients. All derived coefficient sets exhibited smaller noise amplification factor than the global counterpart. A test comparison of satellite-derived SST with an 11-month in situ SST series showed than locally derived coefficients provide smaller scatter (improved precision), and skin-centred bias that requires additional adjustment. Almost identical SST residual and error metric was obtained with seasonally adjusted classical split-window coefficients and with coefficients explicitly accommodating water-vapor dependence. Comparison with data reinforces the notion that the atmosphere over the Adriatic may exhibit variability that cannot be fully accommodated by globally adjusted correction. 相似文献
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A global ocean temperature and altimeter data assimilation system for studies of climate variability 总被引：4，自引：0，他引：4
An ocean data assimilation (ODA) system which can assimilate both temperature and altimeter observations has been applied
to the global ocean and tested between January 1993–October 1996. A statistical method has been used to convert sea surface
height (SSH) anomalies observations from TOPEX/POSEIDON into synthetic temperature profiles. The innovative aspect of this
method is the introduction of time dependency in the correlations used to transform the altimeter observations into temperature
corrections. The assimilation system is based on a univariate variational optimal interpolation scheme applied to assimilate
both in situ and synthetic temperature profiles. In addition, a longer global analysis for the upper-ocean temperature starting
from January 1979 and ending November 1997, has been produced to examine the skill of sea temperature assimilation with a
rather simple and practical method. The temperature analysis shows encouraging improvement over a corresponding ocean simulation
when compared to independent (not assimilated) temperature data both at seasonal and interannual time scales. However, the
univariate data assimilation of hydrographic data does not result in an improvement of the velocity field. In fact the assimilation
of sparse in situ data can introduce unrealistic spatial variability in the temperature field which affects the velocity field
in a negative way. This deficiency is partially overcome when we also assimilate altimeter observations since the coverage
is complete and uniform for this data. In particular, our study shows that temperature corrections due to the altimeter signal
have a positive impact on the current system in the tropical Pacific.
Received: 28 May 2000 / Accepted: 6 November 2000 相似文献
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Detecting and adjusting temporal inhomogeneity in Chinese mean surface air temperature data 总被引：18，自引：0，他引：18
LI Qingxiang LIU Xiaoning ZHANG Hongzheng Thomas C. PETERSON David R. EASTERLING 《大气科学进展》2004,21(2):260-268
Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorolog-ical observations, this paper designed several tests and tested for inhomogeneities in all Chinese historicalsurface air temperature series from 1951 to 2001. The result shows that the time series have been widelyimpacted by inhomogeneities resulting from the relocation of stations and changes in local environmentsuch as urbanization or some other factors. Among these factors, station relocations caused the largestmagnitude of abrupt changes in the time series, and other factors also resulted in inhomogeneities to someextent. According to the amplitude of change of the difference series and the monthly distribution featuresof surface air temperatures, discontinuities identified by applying both the E-P technique and supportedby China‘s station history records, or by comparison with other approaches, have been adjusted. Basedon the above processing, the most significant temporal inhomogeneities were eliminated, and China‘s mosthomogeneous surface air temperature series has thus been created. Results show that the inhomogeneitytesting captured well the most important change of the stations, and the adjusted dataset is more reli-able than ever. This suggests that the adjusted temperature dataset has great value of decreasing theuncertaities in the study of‘ observed climate change in China. 相似文献
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The main objective of the present paper is to show a methodology for undertaking rainfall regionalization of a region taking into account the convective features of the precipitation, and useful for establishing homogeneous zones for improving the alert system. This methodology has been applied to a hydrographic region located in northeast Spain, with an area of 16000 km2 and characterized by a highly contrasted topography. Information provided by meteorological radar and 5-min precipitation data for 126 automatic raingauges has been used for the period 1996–2002. The previous analysis done on the basis of the 1927–1981 rainfall rate series for the Jardí raingauge, located in Barcelona, has also been considered. To that end, the first step was to draw up a proposal for classification of the pluviometric episodes. Recourse was had for this purpose to definition of the β parameter, related with the greater or lesser convective character of the event and calculated on the basis of the rainfall intensity at the surface (Llasat, 2001) and, when data are available, on the basis of radar reflectivity. Results show that the threshold of 35 mm/h to characterize convective episodes from raingauge data can be corroborated from the radar point of view when convective precipitation is identified using 2-D algorithms with a reflectivity threshold of 43 dBZ. Once the soundness of the β parameter had been corroborated, it was applied to more than 2900 precipitation episodes recorded in the region, in order to discriminate the features of the different subregions and their time and space distribution throughout the entire series of the samples. Using this definition, 92% of the precipitation events recorded in this region, with accumulated rainfall above 35 mm, are classified as convective ones, representing 95% of the precipitation amount. Application of the β parameter combined with monthly rainfall data allows differentiation of 8 regions with different convective precipitation features. 相似文献
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地温资料的计算机自动审核方法 总被引：1，自引：2，他引：1
地温观测资料的计算机自动审核技术,是地面气象观测资料计算机自动审核中的一个关键性技术难点。综合分析了地温观测资料的特点和地温观测资料的人工审核方法,提出了地温观测资料“相邻差”的标准差分析方法,详细说明了该方法在计算机自动审核中的具体实现步骤和该方法的特点。由于该方法从本质上讲是对人工审核方法的计算模拟,同时由于采用客观计算方法,避免了主观因素,所以审核质量能达到人工审核质量的要求,且比人工审核更全面。该方法在浙江省地面气象资料计算机自动审核软件中进行了试用,实践证明该方法对提高地温观测资料的审核质量具有明显效果。 相似文献
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A fast, robust and scalable methodology to examine, quantify, and visualize climate patterns and their relationships is proposed. It is based on a set of notions, algorithms and metrics used in the study of graphs, referred to as complex network analysis. The goals of this approach are to explain known climate phenomena in terms of an underlying network structure and to uncover regional and global linkages in the climate system, while comparing general circulation models outputs with observations. The proposed method is based on a two-layer network representation. At the first layer, gridded climate data are used to identify “areas”, i.e., geographical regions that are highly homogeneous in terms of the given climate variable. At the second layer, the identified areas are interconnected with links of varying strength, forming a global climate network. This paper describes the climate network inference and related network metrics, and compares network properties for different sea surface temperature reanalyses and precipitation data sets, and for a small sample of CMIP5 outputs. 相似文献
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We derive a conceptual model of the flow over heterogeneous terrain consisting of patches with contrasting Bowen ratios. Upward
moving eddies are assumed to carry heterogeneous properties, whereas downward moving eddies carry homogeneous properties.
This results in a decorrelation of temperature and humidity as the contrast between the patches increases. We show that this
model is able to reproduce the relationship developed by Lamaud and Irvine (Boundary-Layer Meteorol. 120:87–109, 2006). Some
details differ from their expression but are in accordance with data obtained over African savannah. We extend the conceptual
model to a combination of any scalars, not necessarily linked through the surface energy balance (as is the case for temperature
and humidity). To this end we introduce a new parameter that describes the surface heterogeneity in surface fluxes. The results
of the current model can be used to predict the discrepancy between similarity relationships for different scalars over heterogeneous
terrain. 相似文献
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Estimating the potential predictability of Australian surface maximum and minimum temperature 总被引：1，自引：1，他引：0
A study is made of the potential predictability of seasonal means in Australian surface maximum and minimum temperature using
monthly data from December 1950 to November 2000. Because the usual assumption of stationarity cannot be applied to the observations
at all stations and for all seasons, a modification to an existing methodology is proposed. Here, we show that, to a first
order, monthly mean variances within a season can be modeled by a linear relationship, and inter-monthly correlations can
be assumed to be stationary. The intraseasonal component of variability can then be estimated using monthly data. Removing
the intraseasonal variance from the total interannual variance allows an estimate of the potential predictability to be made.
Surface maximum and minimum temperature has high potential predictability over most of northern Australia in the four main
seasons. However, there is high potential predictability only in some of the four seasons for the centre and south of Australia.
Surface minimum temperature is generally more potentially predictable than surface maximum temperature. The spatial and temporal
patterns of potential predictability are generally consistent with published patterns of hindcast skill from a statistical
forecast scheme. A comparison between the intraseasonal variance of Australian surface maximum and minimum temperature estimated
using the stationary variance assumption and the linear assumptions showed qualitatively and quantitatively similar patterns
of distribution. 相似文献
16.
Grégoire Pigeon Aude Lemonsu Nathalie Long Joël Barrié Valéry Masson Pierre Durand 《Boundary-Layer Meteorology》2006,120(2):315-351
Within the framework of ESCOMPTE, a French experiment performed in June and July 2001 in the south-east of France to study the photo-oxidant pollution at the regional scale, the urban boundary layer (UBL) program focused on the study of the urban atmosphere over the coastal city of Marseille. A methodology developed to optimize a network of 20 stations measuring air temperature and moisture over the city is presented. It is based on the analysis of a numerical simulation, performed with the non-hydrostatic, mesoscale Meso-NH model, run with four nested-grids down to a horizontal resolution of 250 m over the city and including a specific parametrization for the urban surface energy balance. A three-day period was modelled and evaluated against data collected during the preparatory phase for the project in summer 2000. The simulated thermodynamic surface fields were analysed using an empirical orthogonal function (EOF) decomposition in order to determine the optimal network configuration designed to capture the dominant characteristics of the fields. It is the first attempt of application of this kind of methodology to the field of urban meteorology. The network, of 20 temperature and moisture sensors, was implemented during the UBL-ESCOMPTE experiment and continuously recorded data from 12 June to 14 July 2001. The measurements were analysed in order to assess the urban thermodynamic island spatio-temporal structure, also using EOF decomposition. During nighttime, the influence of urbanization on temperature is clear the field is characterized by concentric thermo-pleths around the old core of the city, which is the warmest area of the domain. The moisture field is more influenced by proximity to the sea and airflow patterns. During the day, the sea breeze often moves from west or south-west and consequently the spatial pattern for both parameters is characterized by a gradient perpendicular to the shoreline. Finally, in order to assess the methodology adopted, the spatial structures extracted from the simulation of the 2000 preparatory campaign and observations gathered in 2001 have been compared. They are highly correlated, which is a relevant validation of the methodology proposed. The relations between these spatial structures and geographical characteristics of the site have also been studied. High correlations between temperature spatial structure during nighttime and urban cover fraction or street aspect ratio are observed and simulated. For temperature during daytime or moisture during both daytime and nighttime these geographical factors are not correlated with thermodynamic fields spatial structures. 相似文献
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对临海沙漠地区非均匀地表区域地表能量通量和蒸发(蒸散)的研究,是一个十分重要但又是一个难点问题。本文提出了1个基于卫星遥感和地面观测的参数化方案,并把其应用于沙特阿拉伯吉达地区,利用1个景的陆地资源卫星Landsat-7E^TM^ 资料进行了分析研究,得到了一些有关临海沙漠地区非均匀地表区域地表特征参数、植被参数和地表能量通量的新概念。最后讨论了所提出的参数化方案的适用范围和需改进之处。 相似文献
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M. Burlando 《Theoretical and Applied Climatology》2009,96(1-2):69-83
In 2008, Burlando et al. proposed a two-stage clustering technique for the classification of mesoscale wind regimes. The first stage of this classification scheme is based on a hierarchical cluster analysis, according to Ward’s minimum variance technique applied to an Euclidean distance, for a first-guess subdivision of the events into groups. In the second stage, a partitional k-means clustering for the optimal reassignment of the events among clusters is performed. Following this methodology, in the present paper, the synoptic-scale wind fields over the Mediterranean Sea have been analysed in order to check the suitability of this technique to a higher-dimensional phase space. The study is based on a 30-year-long data set of wind speed and direction at 10 m above sea level obtained from the reanalysis of the European Centre for Medium-range Weather Forecasts. The cluster analysis has been performed on wind speeds only, while wind directions have been used to show the existence, in the spatial structure of the wind climate regimes, of particular regions which correspond to the main topographic and/or thermal forcing of the Mediterranean. These regions are the peaks of the probability density function in the climatological phase space of wind speed patterns recognised by the clustering algorithm. The final classification has been able to identify, for instance, the surface circulation patterns corresponding to Mistral events in the western Mediterranean sub-basin and Etesian winds in the eastern sub-basin. 相似文献
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An acoustic Doppler sounder has been used to document the behaviour of the stable atmospheric boundary layer during the “Coast” experiment, in April-May, 1983, on a homogeneous terrain near the Dutch coast. It has been shown that kaimal's model of the spectrum of velocity in the stable surface layer can be applied and that surface-layer parameterization can be used in the whole stable surface layer. Velocity spectra have been computed between .0005 c.p.s. and .1 c.p.s. and for the stability range for z/L between 0 and 10. It is to be noted that the information has been obtained using only sodar data. 相似文献