共查询到20条相似文献，搜索用时 31 毫秒
1.
R. B. Zaripov Yu. V. Martynova V. N. Krupchatnikov A. P. Petrov 《Russian Meteorology and Hydrology》2016,41(11-12):808-815
The system of the cyclic assimilation of data on atmospheric conditions used in the West Siberian Administration for Hydrometeorology and Environmental Monitoring is described. It is based on the WRF-ARW mesoscale atmospheric model and on the WRF 3D-Var system of the three-dimensional variational analysis of data. The system is verified when the first approximation data (6-hour forecast) and WRF-ARW forecasts with the lead time up to 24 hours are compared with the observational data. The problems of assimilation of observations from the AMSU-A and AIRS satellite instruments are considered. The effect of using AMSU-A and AIRS for the analysis in the Novosibirsk region is estimated. The experiments demonstrated that the cyclic data assimilation system operates successfully. The AMSU-A observations improve the quality of analyses and forecasts in winter. In summer the impact of satellite observations on the forecast skill scores is ambiguous. Good short-term forecasts are provided by the initial conditions obtained using the system of detailing of the NCEP large-scale analysis. 相似文献
2.
N. A. Kalinin A. L. Vetrov E. V. Pishchal’nikova E. M. Sviyazov A. N. Shikhov 《Russian Meteorology and Hydrology》2016,41(3):193-198
The results of the forecast of two heavy snowfalls registered on October 18 and 23, 2014 in the Urals using the WRF model are presented. The application of the WRF-ARW atmospheric model to the computation of weather forecasts for the conditions of heavy widespread precipitation in the form of snow is considered. The obtained estimates of precipitation forecast are compared with the estimates of the GFS NCEP global model. The results demonstrate that both models have approximately the same accuracy of precipitation forecast in the context of the process under consideration. 相似文献
3.
V. I. Bychkova M. M. Kurbatova G. A. Zarochentsev R. Yu. Ignatov 《Russian Meteorology and Hydrology》2018,43(7):444-448
The object under study is the blowing snow, i.e., the transport of snow lifted from the snow surface. The method is described for predicting the blowing snow initiation using the output data of the WRF-ARW numerical atmospheric model. The skill scores are presented for the forecasts for January 2013 calculated from data of 10 stations of the Canadian weather observation network. 相似文献
4.
2013年汛期华中区域业务数值模式降水预报检验 总被引：4，自引：0，他引：4
为充分了解华中区域中尺度业务数值预报模式更新为WRF后的预报性能,对该模式2013年汛期24 h和48 h的累积降水预报产品,采用TS评分、预报正确率、漏报率、空报率、偏差及ETS评分等统计量对其进行了较详细的评估。结果表明：从日平均降水率分布来看,24 h预报的降水中心位置和强度与实况更接近,48 h的预报明显偏大、偏强;汛期总体降水检验表明,该模式的降水预报以偏大为主,随着降水量级的增大,TS和ETS评分逐渐减小,且ETS评分逐渐靠近TS;逐月降水检验结果发现,该区域汛期月晴雨预报正确率与雨日率呈正相关;通过梅雨期WRF与GRAPES_Meso的预报对比检验可见,两个模式都表现出了较好的预报性能。值得指出的是,随着降水量级的增大,WRF模式降水预报优势逐渐显现。总的来说,该模式的降水预报产品具有一定的参考价值。 相似文献
5.
Yoo-Geun Ham Siegfried Schubert Yury Vikhliaev Max J. Suarez 《Climate Dynamics》2014,43(9-10):2415-2430
The seasonal forecast skill of the NASA Global Modeling and Assimilation Office atmosphere–ocean coupled global climate model (AOGCM) is evaluated based on an ensemble of 9-month lead forecasts for the period 1993 to 2010. The results from the current version (V2) of the AOGCM consisting of the GEOS-5 AGCM coupled to the MOM4 ocean model are compared with those from an earlier version (V1) in which the AGCM (the NSIPP model) was coupled to the Poseidon Ocean Model. It was found that the correlation skill of the Sea Surface Temperature (SST) forecasts is generally better in V2, especially over the sub-tropical and tropical central and eastern Pacific, Atlantic, and Indian Ocean. Furthermore, the improvement in skill in V2 mainly comes from better forecasts of the developing phase of ENSO from boreal spring to summer. The skill of ENSO forecasts initiated during the boreal winter season, however, shows no improvement in terms of correlation skill, and is in fact slightly worse in terms of root mean square error (RMSE). The degradation of skill is found to be due to an excessive ENSO amplitude. For V1, the ENSO amplitude is too strong in forecasts starting in boreal spring and summer, which causes large RMSE in the forecast. For V2, the ENSO amplitude is slightly stronger than that in observations and V1 for forecasts starting in boreal winter season. An analysis of the terms in the SST tendency equation, shows that this is mainly due to an excessive zonal advective feedback. In addition, V2 forecasts that are initiated during boreal winter season, exhibit a slower phase transition of El Nino, which is consistent with larger amplitude of ENSO after the ENSO peak season. It is found that this is due to weak discharge of equatorial Warm Water Volume (WWV). In both observations and V1, the discharge of equatorial WWV leads the equatorial geostrophic easterly current so as to damp the El Nino starting in January. This process is delayed by about 2 months in V2 due to the slower phase transition of the equatorial zonal current from westerly to easterly. 相似文献
6.
Soil moisture exhibits outstanding memory characteristics and plays a key role within the climate system. Especially through its impacts on the evapotranspiration of soils and plants, it may influence the land energy balance and therefore surface temperature. These attributes make soil moisture an important variable in the context of weather and climate forecasting. In this study we investigate the value of (initial) soil moisture information for sub-seasonal temperature forecasts. For this purpose we employ a simple water balance model to infer soil moisture from streamflow observations in 400 catchments across Europe. Running this model with forecasted atmospheric forcing, we derive soil moisture forecasts, which we then translate into temperature forecasts using simple linear relationships. The resulting temperature forecasts show skill beyond climatology up to 2 weeks in most of the considered catchments. Even if forecasting skills are rather small at longer lead times with significant skill only in some catchments at lead times of 3 and 4 weeks, this soil moisture-based approach shows local improvements compared to the monthly European Centre for Medium Range Weather Forecasting (ECMWF) temperature forecasts at these lead times. For both products (soil moisture-only forecast and ECMWF forecast), we find comparable or better forecast performance in the case of extreme events, especially at long lead times. Even though a product based on soil moisture information alone is not of practical relevance, our results indicate that soil moisture (memory) is a potentially valuable contributor to temperature forecast skill. Investigating the underlying soil moisture of the ECMWF forecasts we find good agreement with the simple model forecasts, especially at longer lead times. Analyzing the drivers of the temperature forecast skills we find that they are mainly controlled by the strengths of (1) the soil moisture-temperature coupling and (2) the soil moisture memory. We find a negative relationship between these controls that weakens the forecast skills, nevertheless there is a middle ground between both controls in several catchments, as shown by our results. 相似文献
7.
针对B08RDP(The Beijing 2008 Olympics Research and Development Project)5套区域集合预报资料,系统分析了各套集合预报温度场的预报质量。在此基础上运用集合预报的综合偏差订正方法对温度场进行偏差订正,并对其效果进行了分析讨论。结果显示:5套B08RDP区域集合预报中,美国国家环境预报中心(NCEP)区域集合预报温度场的整体预报质量最高,平均预报误差最小,离散度也最为合理,预报可信度和可辨识度均较优;而中国气象科学研究院(CAMS)的温度预报误差过大,预报质量最差。整体上看,除NCEP之外的4套集合预报的温度场均存在集合离散度偏小的问题;综合偏差订正能有效减小各集合预报温度场的集合平均均方根误差,改善集合离散度的质量,显示出综合偏差订正方案对集合预报温度场偏差订正的良好能力。 相似文献
8.
9.
Kim-Chiu Chow Lin Su Jimmy C. H. Fung Hui Ma Alexis K. H. Lau 《Meteorology and Atmospheric Physics》2014,126(3-4):119-138
The mesoscale model WRF-Chem was used to simulate a severe dust storm event that occurred in March 2010. The storm affected a vast area of East Asia, including the south China region and Hong Kong. This southern region is rarely affected by dust weather. The performance of the WRF-Chem was evaluated by observational data such as the National Center for Atmospheric Research reanalysis data for atmospheric circulation, PM10 concentration from various ground stations, and satellite images of Moderate Resolution Imaging Spectroradiometer and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. The dependence of the model’s performance on certain important parameterizations was examined in this study. For this particular dust storm event, the model results suggest that the simulation is not very sensitive to certain key physical parameterizations such as threshold wind speed of dust emission and the choice of land surface model. In general, the WRF-Chem is capable of capturing the key physical processes for this severe dust event. The analysis of the dust transport fluxes suggests that the dust transport to the south China region is mainly from the north, although there is a mountainous region in the northern part of the south China region. 相似文献
10.
P. Sabo 《Meteorology and Atmospheric Physics》2003,84(1-2):23-32
Summary ¶The cold seasons (October to March) of the years 1960 to 1984 have been investigated for inversions around Vienna. The basic material consists of climate and synoptic data as well as soundings taken at 0000UTC and 1200UTC at Vienna – Hohe Warte.These observations are filtered in three steps. First all days with inversions in the planetary boundary layer are selected which yields 1795 cases. For these cases the sounding data are used to calculate a so called inversion index I. This index has been developed as an objective measure for the intensity and the vertical extent of inversions. It is used as criterion for the information of low stratus. The second filter discards episodes with precipitation leaving 664 cases with dry but cloudy or foggy weather in the low lands. These remaining cases, for which the large scale weather patterns are determined, are again filtered to leave those with clear skies on the mountains, yielding 187 final cases. They are used to define rules for the formation of low stratus around Vienna, comprising rules for the time of onset and the persistency of low stratus. Further the large scale weather patterns leading to such situations are determined and the limiting values of the inversion index associated with persistent low stratus are found for every month of the cold saison of the year. So this work aims at improving the score of forecasting the formation and persistence of low stratus in the region of Vienna. There was made a verification with this inversion index for the cold season 1999/2000. Using the inversion index the results show that the score of low stratus forecasts are improving. In nearly 30% oft the investigated cases (16 out of 57) the forecasts would have been better, in 62% (36 out of 57) the criteria of the inversion index would have supported the forecasts.Received May 31, 2001; revised April 3, 2002; accepted August 12, 2002
Published online: May 8, 2003 相似文献
11.
从2011/2012和2015/2016年冬季大气环流异常看北极海冰以及前期夏季北极大气环流异常的作用 总被引：1，自引：0，他引：1
利用美国NCEP/NCAR、欧洲中心ERA-Interim再分析资料,以及英国哈得来中心海冰密集度资料,通过诊断分析和数值模拟试验,研究了2011/2012和2015/2016年两个冬季大气环流异常的主要特征和可能原因。结果表明,尽管热带太平洋海温背景截然不同（分别为弱的拉尼娜事件和强厄尔尼诺事件）,但这两个冬季西伯利亚高压均异常偏强,自1979年以来其强度分别排第1和第5位。前期秋季北极海冰异常偏少是导致这两个冬季西伯利亚高压偏强的主要原因。更为重要的是,前期夏季北冰洋表面反气旋风场,以及其上空对流层中、低层平均气温偏高,加强了北极海冰偏少对冬季大气变率的负反馈,进一步促进了西伯利亚高压的加强,从而有利于东亚地区冬季阶段性强严寒的出现。因此,夏季北极大气环流的动力和热力状态不仅影响夏、秋季北极海冰,而且对海冰偏少影响亚洲冬季气候变率有重要调节作用。2015/2016年冬季强厄尔尼诺事件并不能掩盖来自北极海冰和大气环流的影响。 相似文献
12.
Described is a system for analyzing and forecasting the air quality in the central regions of Russia, During the operation of the system, the detailed meteorological information provided by the WRF-ARW model is used by the CHIMERE chemistry transport model for simulating the processes of transport, chemical transformation, and deposition of atmospheric minor constituents. Considered is the quality of retrieved and forecasted (with the lead time up to three days) concentrations of O3, NO2, NO, CO, and PM10. The presented verification scores of pollutant concentrations demonstrate a relative success of the system. Demonstrated is a need in improving the data on the emissions of the air pollutants used for simulations. A procedure for the statistical correction of computed concentrations is described and verification scores of its results are given. 相似文献
13.
14.
Cortesi Nicola Torralba Ver&#;nica Lled&#; Lloren&#; Manrique-Su&#;&#;n Andrea Gonzalez-Reviriego Nube Soret Albert Doblas-Reyes Francisco J. 《Climate Dynamics》2021,56(11):3933-3964
It is often assumed that weather regimes adequately characterize atmospheric circulation variability. However, regime classifications spanning many months and with a low number of regimes may not satisfy this assumption. The first aim of this study is to test such hypothesis for the Euro-Atlantic region. The second one is to extend the assessment of sub-seasonal forecast skill in predicting the frequencies of occurrence of the regimes beyond the winter season. Two regime classifications of four regimes each were obtained from sea level pressure anomalies clustered from October to March and from April to September respectively. Their spatial patterns were compared with those representing the annual cycle. Results highlight that the two regime classifications are able to reproduce most part of the patterns of the annual cycle, except during the transition weeks between the two periods, when patterns of the annual cycle resembling Atlantic Low regime are not also observed in any of the two classifications. Forecast skill of Atlantic Low was found to be similar to that of NAO+, the regime replacing Atlantic Low in the two classifications. Thus, although clustering yearly circulation data in two periods of 6 months each introduces a few deviations from the annual cycle of the regime patterns, it does not negatively affect sub-seasonal forecast skill. Beyond the winter season and the first ten forecast days, sub-seasonal forecasts of ECMWF are still able to achieve weekly frequency correlations of r = 0.5 for some regimes and start dates, including summer ones. ECMWF forecasts beat climatological forecasts in case of long-lasting regime events, and when measured by the fair continuous ranked probability skill score, but not when measured by the Brier skill score. Thus, more efforts have to be done yet in order to achieve minimum skill necessary to develop forecast products based on weather regimes outside winter season.
相似文献15.
This study examines the forecast performance of tropical intraseasonal oscillation (ISO) in recent dynamical extended range
forecast (DERF) experiments conducted with the National Centers for Environmental Prediction (NCEP) Global Forecasting System
(GFS) model. The present study extends earlier work by comparing prediction skill of the northern winter ISO (Madden-Julian
Oscillation) between the current and earlier experiments. Prediction skill for the northern summer ISO is also investigated.
Since the boreal summer ISO exhibits northward propagation as well as eastward propagation along the equator, forecast skill
for both components is computed. For the 5-year period from 1 January, 1998 through 31 December, 2002, 30-day forecasts were
made once a day. Compared to the previous DERF experiment, the current model has shown some improvements in forecasting the
ISO during winter season so that the skillful forecasts (anomaly correlation>0.6) for upper-level zonal wind anomaly extend
from the previous shorter-than 5 days out to 7 days lead-time. A similar level of skill is seen for both northward and eastward
propagation components during the summer season as in the winter case. Results also show that forecasts from extreme initial
states are more skillful than those from null phases for both seasons, extending the skillful range by 3–6 days. For strong
ISO convection phases, the GFS model performs better during the summer season than during the winter season. In summer forecasts,
large-scale circulation and convection anomalies exhibit northward propagation during the peak phase. In contrast, the GFS
model still has difficulties in sustaining ISO variability during the northern winter as in the previous DERF run. That is,
the forecast does not maintain the observed eastward propagating signals associated with large-scale circulation; rather the
forecast anomalies appear to be stationary at their initial location and decay with time. The NCEP Coupled Forecast System
produces daily operational forecasts and its predication skill of the MJO will be reported in the future. 相似文献
16.
Burghard Brümmer Amélie Kirchgäßner Gerd Müller 《Theoretical and Applied Climatology》2014,118(4):641-653
The regional model REMO, which is the atmospheric component of the coupled atmosphere–ice–ocean–land climate model system BALTIMOS, is tested with respect to its ability to simulate the atmospheric boundary layer over the open and ice-covered Baltic Sea. REMO simulations are compared to ship, radiosonde, and aircraft observations taken during eight field experiments. The main results of the comparisons are: (1) The sharpness and strength of the temperature inversion are underestimated by REMO. Over open water, this is connected with an overestimation of cloud coverage and moisture content above the inversion. (2) The vertical temperature stratification in the lowest 200 m over sea ice is too stable. (3) The horizontal inhomogeneity of sea ice concentration as observed by aircraft could not be properly represented by the prescribed ice concentration in REMO; large differences in the surface heat fluxes arise especially under cold-air advection conditions. The results of the comparisons suggest a reconsideration of the parameterization of subgrid-scale vertical exchange both under unstable und stable conditions. 相似文献
17.
Arctic sea ice responds to atmospheric forcing in primarily a top-down manner, whereby near-surface air circulation and temperature govern motion, formation, melting, and accretion. As a result, concentrations of sea ice vary with phases of many of the major modes of atmospheric variability, including the North Atlantic Oscillation, the Arctic Oscillation, and the El Niño-Southern Oscillation. However, until this present study, variability of sea ice by phase of the leading mode of atmospheric intraseasonal variability, the Madden–Julian Oscillation (MJO), which has been found to modify Arctic circulation and temperature, remained largely unstudied. Anomalies in daily change in sea ice concentration were isolated for all phases of the real-time multivariate MJO index during both summer (May–July) and winter (November–January) months. The three principal findings of the current study were as follows. (1) The MJO projects onto the Arctic atmosphere, as evidenced by statistically significant wavy patterns and consistent anomaly sign changes in composites of surface and mid-tropospheric atmospheric fields. (2) The MJO modulates Arctic sea ice in both summer and winter seasons, with the region of greatest variability shifting with the migration of the ice margin poleward (equatorward) during the summer (winter) period. Active regions of coherent ice concentration variability were identified in the Atlantic sector on days when the MJO was in phases 4 and 7 and the Pacific sector on days when the MJO was in phases 2 and 6, all supported by corresponding anomalies in surface wind and temperature. During July, similar variability in sea ice concentration was found in the North Atlantic sector during MJO phases 2 and 6 and Siberian sector during MJO phases 1 and 5, also supported by corresponding anomalies in surface wind. (3) The MJO modulates Arctic sea ice regionally, often resulting in dipole-shaped patterns of variability between anomaly centers. These results provide an important first look at intraseasonal variability of sea ice in the Arctic. 相似文献
18.
Atmospheric variability is driven not only by internal dynamics, but also by external forcing, such as soil states, SST, snow, sea-ice cover, and so on. To investigate the forecast uncertainties and effects of land surface processes on numerical weather prediction, we added modules to perturb soil moisture and soil temperature into NCEP’s Global Ensemble Forecast System (GEFS), and compared the results of a set of experiments involving different configurations of land surface and atmospheric perturbation. It was found that uncertainties in different soil layers varied due to the multiple timescales of interactions between land surface and atmospheric processes. Perturbations of the soil moisture and soil temperature at the land surface changed sensible and latent heat flux obviously, as compared to the less or indirect land surface perturbation experiment from the day-to-day forecasts. Soil state perturbations led to greater variation in surface heat fluxes that transferred to the upper troposphere, thus reflecting interactions and the response to atmospheric external forcing. Various verification scores were calculated in this study. The results indicated that taking the uncertainties of land surface processes into account in GEFS could contribute a slight improvement in forecast skill in terms of resolution and reliability, a noticeable reduction in forecast error, as well as an increase in ensemble spread in an under-dispersive system. This paper provides a preliminary evaluation of the effects of land surface processes on predictability. Further research using more complex and suitable methods is needed to fully explore our understanding in this area. 相似文献
19.
The results are presented ofmodeling the formation and evolution ofmesoscale convective systems (MCS) accompanied by severe weather events over the territory of the Western Urals by the WRF-ARW numerical model of the atmosphere. Twenty-three cases of mesoscale convective complexes and mesoscale squall lines are considered for 2002-2015. The Terra/Aqua MODIS data, the data of weather radars installed in Perm and Izhevsk, and the data from the Roshydromet observation network were used to verify the model forecasts. It is demonstrated that the parameters of MCS intensity are simulated by the model with high reliability; however, the quality of the forecast of the spatial position of MCS is unsatisfactory in most cases. It is revealed that the model grid spacing strongly affects the forecast skill scores. In some cases the model successfully simulates the formation and evolution of MCS accompanied by severe weather events and can be used for their short-range forecast with the time accuracy of ±(1-2) hours. 相似文献