应用气象学报

The Current Status and Future Development of Modern Climate Operation in China

Song Lianchun, Xiao Fengjin, Li Wei

2013, 24(5): 513-520.

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Abstract:
The current situation of modern climate operation in China is summarized, based on reviewing different aspects which include climate system monitoring and prediction, the climate system model, climatic assessment and disaster risk management, climate change and climate operation platform. The concept of modern climate operation is proposed, aiming at improvement of climate service, climate risk management and climate change adaptation. Its core is to develop objective prediction skill and quantified assessment method based on climate system monitoring and dynamics diagnosis. The future development of international climate operation and the deficiency of China modern climate operation are also analyzed. The implementation plan of modern climate operation in China is described clearly, including strengthening the monitoring of essential climatic variables, increasing resolution and improving physical processes in the climate system model, developing the second generation of short-term climate prediction system, seeking the assessment method of meteorological disaster and building China framework of climate service (CFCS).

A Review of Physical Mechanisms of the Global SSTA Impact on EASM

Chen Lijuan, Yuan Yuan, Yang Mingzhu, Zuo Jinqing, Li Weijing

2013, 24(5): 521-532.

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Abstract:
The impact of global sea surface temperature anomaly (SSTA) on the East Asia Summer Monsoon (EASM) and summer precipitation in China is reviewed from the aspects of physical mechanisms, on the basis of key external forcing signals in short-term climate prediction. Focusing on El Niño-Southern Oscillation (ENSO) cycle in the tropical Pacific and the main SSTA modes in Indian and Atlantic Ocean, their inter-annual variability are further reviewed as well as their different impacts on the EASM, especially their relationship with the main summer rainfall belt in China.During different phases of ENSO cycle, ENSO exerts different impacts on the EASM and the summer precipitation in China. In the developing summer of El Niño, the EASM tends to be weak and the main summer rainfall belt would shift southward in eastern China. However, in the decaying summer of El Niño, the EASM tends to be strong, and the summer precipitation would be below normal in the Yangtze-Huaihe Valley. The situations are approximately reverse for the impact of La Ni a on the EASM and summer precipitation in China, although the impact of La Ni a is not as significant. The influence of ENSO on the EASM and the summer rainfall belt in China is closely correlated with the SSTA in the western Pacific warm pool as well as the resulted convective activities in its northern part. Moreover, the Philippine Sea anticyclone also plays an important role. In recent years, different types of El Niño are widely discussed. It is revealed that the Central Pacific (CP) El Niño not only has different evolution mechanisms, but also shows different impacts on the global atmospheric circulation as compared with the Eastern Pacific (EP) El Niño or classical El Niño.Indian Ocean SSTA modes also show significant influences on the EASM and the summer precipitation in China. For example, the basin-wide warming (cooling) mode in the tropical Indian Ocean would cause a late (an early) South China Sea summer monsoon (SCSSM) onset; in the summer of positive (negative) tropical Indian Ocean dipole phase, more precipitation would occur in South China (North China); during the positive (negative) phase of subtropical southern Indian Ocean dipole, Indian summer monsoon tends to be stronger (weaker), and SCSSM may establish earlier (later). The positive (negative) North Atlantic tri-pole mode would lead to a stronger (weaker) EASM through motivating quasi-barotropic zonal tele-connection wave train across the Eurasian continent.SSTA is the important pre-signal on the prediction of summer precipitation anomaly in China. Because of the predictability of short-term climate prediction, it is still difficult to give high skill prediction for summer rainfall anomaly in China. Some advices and requirements on the physical mechanism research and dynamical model development are proposed in order to improve the prediction of the EASM and summer rainfall in China.

Progress in Developing the Short-range Operational Climate Prediction System of China National Climate Center

Wu Tongwen, Song Lianchun, Liu Xiangwen, Li Qiaoping, Liang Xiaoyun, Cheng Yanjie, Zhou Wei, Nie Suping, Zhang Li, Jie Weihua, Fang Yongjie, Zhang Yanwu, Lu Yixiong, Chu Min, Li Jianglong

2013, 24(5): 533-543.

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Abstract:
The progress in developing the second-generation short-range climate forecast system of National (or Beijing) Climate Center (NCC or BCC) is introduced, focusing on four items, i.e., the global ocean data assimilation system, the land data assimilation system, the monthly-scale dynamical extended-range forecast system (DERF), and the seasonal climate forecast system. With a better assimilation of temperature and salinity than the first-generation system, the second-generation ocean data assimilation system is now at the quasi-operational level. The land data assimilation system is still under development, but the multisource precipitation merging subsystem is now quasi-operational and can produce reanalysis of precipitation as a forcing to land system. The atmospheric general circulation model BCC_AGCM2.2 and the climate system model BCC_CSM1.1(m) are the main tools for the second-generation monthly-scale DERF and the second-generation seasonal prediction system, respectively. The former has entered quasi-operational use since middle August of 2012 and conducted four-member real-time forecast jobs and 80 hindcast jobs every day, and the latter will enter its quasi-operational stage by the end of 2013. A preliminary evaluation indicates that the second-generation system shows a certain capability in predicting the pentad, ten-day, monthly, seasonal and inter-annual climate variability. It exhibits a higher prediction skill, compared to the first-generation system, in terms of precipitation, surface air temperature, atmospheric circulation and El Ni o-Southern Oscillation, and so on. As shown by the hindcasts by two generations of DERF (i.e., DERF1.0 and DERF2.0) for the monthly mean surface air temperature in January and July, DERF2.0 shows overall higher prediction skill than DERF1.0, especially over the tropical Indian Ocean and Pacific and most mid-high latitude areas in the Northern Hemisphere in January, and most regions in global tropics and subtropics in July. Also, the 20-year hindcasts initialized in the end of February of each year by the two generations of seasonal climate prediction system indicate that, the second-generation system shows significant prediction skill of surface air temperature over most areas in spring, especially over the tropical Pacific, Atlantic and Indian Ocean. In contrast, the skills over most areas of the first-generation system are relative lower.

Improvement of Satellite-based Precipitation Estimates over China Based on Probability Density Function Matching Method

Yu Jingjing, Shen Yan, Pan Yang, Zhao Ping, Zhou Zijiang

2013, 24(5): 544-553.

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Abstract:
In the evaluation and adjustment of satellite-based precipitation estimates, the gauge-based precipitation data is usually taken as the objective criteria. Assuming gauge-based analysis at grid boxes with station reports as the true value, the satellite precipitation data are corrected after adjusting probability density function (PDF), which makes the PDF distribution of the corrected measurements the same as that of the station observation. One advantage of the PDF method is that it can remove the range dependent bias effectively, which is also the main cause for its recent popularity in correcting the error of satellite-based precipitation estimations.Aiming to investigate the applicability of the PDF method, and then to adjust the systematic bias of the high resolution satellite-based precipitation estimations over China, the daily satellite precipitation data with the resolution of 0.25° by 0.25° and hourly data of 0.1° by 0.1°from CMORPH (Climate Prediction Center Morphing Technique) are adjusted, based on grid precipitation data interpolating stations collected and quality controlled by NMIC (National Meteorological Information Center) of China Meteorological Administration. Although CMORPH data has good performance on the space structure of rainfall over China in summer time, it has obvious systematic errors. CMORPH data underestimate large precipitation values while overrate small ones.After analyzing the bias characteristic of CMORPH precipitation data, different matching schemes are designed by adjusting PDF matching samples of spatial and temporal scale separately. The generalized cross-validation (GCV) statistical tests are used in evaluating the quality of correcting data. The evaluation results suggest that the PDF distribution and precipitation values of corrected precipitation products are close to those of the gauge-based precipitation. Both adjusted daily and hourly satellite precipitation data over China get a less systematic bias than the original ones. Even in the area of sparse observations, such as the Western China, the improvement is also remarkable. The adjusted rainfall data over the Western China not only maintain the basic spatial construction of original satellite products, but also improves their quantity value through closing them to the gauge observations. So the research demonstrates that the PDF method is an effective way in correcting systematic bias of satellite-based precipitation estimates over China.

Characteristics of Multi-patterns of Precipitation over the Yangtze-Huaihe Basins During Meiyu Season in Recent 30 Years

Hu Jinggao, Zhou Bing, Xu Haiming

2013, 24(5): 554-564.

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Abstract:
The spatial patterns of precipitation during Meiyu season (June—July) over the Yangtze-Huaihe Basins are analyzed under different distributions of surface stations. 424 stations to the east of 110°E are chosen for the rotated empirical orthogonal function (REOF) analysis during 1979—2010. Then, three precipitation patterns are obtained, i.e., the south pattern (SP), the Yangtze pattern (YP), and the Yangtze-Huaihe pattern (YHP).On the inter-annual time scale, it's found that the out-of-phase relationship displays more remarkably between the rainfall of SP and YHP in recent 30 years. However, the precipitation of YP shows no significant relationship with that of SP and YHP, revealing as more independent precipitation pattern. In addition, the YP has the most climatological precipitation, and shows the largest variability. While on the inter-decadal time scale, the YP precipitation is identical with that of SP. Nevertheless, the precipitation of YHP exhibits out-of-phase relationship with the YP and SP, especially since the early 1990s. There are obvious inter-decadal changes in the early 1990s and early 2000s in all spatial precipitation patterns during Meiyu season. But different from the previous years, by 2010, the YP and SP precipitation has increased a little but the YHP precipitation has decreased, suggesting a new inter-decadal variation.The regression using ERA-Interim reanalysis data indicates that corresponding to the anomalous precipitation, the intensities and positions of sub-systems of East Asian summer monsoon circulations, such as the south Asia high (SAH), the western Pacific subtropical high (SH) and the subtropical upper jet stream (JS), have notable differences which also exist in the monsoon meridional circulations and water vapor transport flux. Specifically, when the YP precipitation is in the flood years, the intensities of the SAH and SH enhance apparently. When the YHP precipitation is strong, the SAH and JS locate east, meanwhile, the geopotential height over Aleutian Islands maintain positive anomalies. The positive phase of the East Asia-Pacific teleconnection pattern and the negative phase of the Eurasian teleconnection pattern make it difficult for the SH to shift northward and confine it to a southern position, which in turn enhance the SP rainfall remarkably. Additionally, it is found that the SH, the monsoon meridional circulations, together with the vertically integrated water vapor transport flux stay successively in northern places, accompanying by a northerly rainfall pattern. Further analyses on sea surface temperature (SST) present that the previous SST of the east Pacific Ocean of the equator shows significant relationship with the precipitation of YP and SP. The cool SST of the western Pacific warm pool and warm SST in Chinese coasts and the Kuroshio area restrain the precipitation in the SP. But there is no distinct correlation between the precipitation of YHP and the tropical SST in the prior period, which implies that the tropical SST plays no key role in the YHP precipitation since 1979.

The Multi-timescale Features for Guangxi Summer Precipitation and the Related Predictors

Qin Zhinian, Hu Yamin, Chen Lijuan

2013, 24(5): 565-575.

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Abstract:
Based on NCEP/NACR reanalysis data and Guangxi summer precipitation (GSP) station data, using the correlation analysis, composite analysis, empirical orthogonal function (EOF), empirical mode decomposition (EMD), abrupt change test and the statistic significant test methods, GSP multi-timescale characteristics and their related circulation as well as the external forcing features are analyzed. According to the diagnostic analysis, the fitting and the prediction equation of GSP are proposed by the multivariate linear regression method.GSP is mainly influenced by the mid-latitude height field anomaly in Lake Baikal region, the subtropical high and monsoon trough (MonTr) in the subtropical region, the low level jet (LLJ) and upper level jet (ULJ) in the same season, as well as the sea surface temperature (SST) anomaly in the eastern of the South Indian Ocean in the pre-winter and pre-spring.The possible physical concept model for GSP is that, when MonTr, LLJ, and the easterly to the south of the subtropical high (ESTH) occur at 850 hPa wind field, the blocking high (BH) over Lake Baikal at 500 hPa potential height, as well as ULJ over South China at 200 hPa wind field are stronger (weaker) than normal, and the subtropical high ridge location is northward (southward) to its normal position, the rainfall is more. The influences of circulation may impact summer rainfall anomaly through the multi-timescale features.Using EMD method, there are 5 principle modes for the summer rainfall. The variance contributions from the first to the fourth intrinsic mode function (IMF1—IMF4) are 55%, 18%, 12% and 12%, respectively. The periods over the statistic significant test are quasi-2 years, 7.6 years, 12.7 years and 19 years. On the scale of quasi-2 years, the summer rainfall is affected by the corresponding IMF1 components of the MonTr, LLJ, ULJ, BH over Lake Baikal, SST anomaly in the east of the South Indian Ocean. The summer rainfall has high relationship with the other influenced indexes on the different time scales.Using IMF1—IMF4 components of circulation factors and the multivariate linear regression method, the summer precipitation equation is fitted. The results show that the multiple correlation coefficients reach 0.73 with the significant level over 0.05. The tests verify that the summer precipitation is really influenced by the multi-timescale components of different factors.Furthermore, based on the IMFs of SST anomaly in the east of southern Indian in winter, the prediction model of the summer precipitation is constructed by the multivariate linear regression method. The trends of the 6 independent sample tests are accord with that of the observation. This method provides an idea in the regional climate prediction based on the multi-timescale features of predictant and predictor.

Applications of Ground-based Microwave Radiation Data to Short-term Rainstorm and Potential Forecast

Huang Zhiyong, Xu Guirong, Wang Xiaofang, Tang Yonglan

2013, 24(5): 576-584.

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Abstract:
Microwave radiometer (MWR) can derive the profiles of relative humidity, atmospheric liquid water content, and atmospheric water vapor content with high temporal resolution. Using MWR measurements from June 2008 to August 2012 of Xianning Station in Hubei Province operated by the Institute of Heavy Rain, CMA, based on 523 precipitation cases, the characteristics of MWR measurements before the occurrences of short-term rainstorms with more than 50 mm precipitation in 3 hours or 6 hours and other general rainfalls are analyzed, and the applications of MWR measurements in the forecast of short-term rainstorms are explored. For both short-term rainstorms and general rainfalls, the relative humidity in 0—6 km heights is close to saturation or is saturating in 3 hours before the rainfall occurrence, and no distinct difference is found between these two kinds of precipitations, however, the transforming of relative humidity from unsaturation to saturation always means the occurrence of rainfall process. Within 12 hours before the short-term rainstorm occurrence, the integrated liquid water (ILW) increases sharply from about 1 mm to about 20 mm, and the integrated water vapor (IWV) increases rapidly from 60—70 mm to 90 mm or more, which are helpful for the potential analysis of short-term rainstorm forecast. Compared with the short time rainstorm, amplitude and rate of occurrence of precipitation of ILW and IWV growth will be much smaller.Within 6 hours before the short-term rainstorm occurrence, a temperature inversion layer exists near 800—950 hPa, and the largest K index and TT index are above 35℃ and 40℃, respectively, otherwise, the atmospheric stratification curve is unstable, and the unstable energy may be larger than 1000 J·kg^-1 or maybe small depending on the maintenance of weak precipitation before the rainstorm occurrence.Of all the historical cases, there is a part of general rainfalls also occur with unstable atmosphere and temperature inversion at the bottom level. Therefore, it cannot be determined whether short-time rainstorm will occur only by the atmospheric stratification stability. In conclusion, when the ILW increases sharply from about 1 mm to about 20 mm, and the IWV increases rapidly from 60—70 mm to 90 mm or more, if the relative humidity is close to saturation or is saturating in 0—6 km heights, and a temperature inversion layer exists near 800—950 hPa, and additionally, the largest K and TT index are above 35℃ and 40℃, then the probability of the occurrence of a short-term rainstorm is large in coming 3 hours or 6 hours. The verification with 519 other general rainfall cases shows that, using these criterions, 2 cases matches the above characteristics, and the false alarm rate is about 0.4%.

Simulation and Analysis of the Relationship Between the Turbine Blade Condition and Its Lightning Strike Probability

Li Dan, Zhang Yijun, Lü Weitao

2013, 24(5): 585-594.

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Abstract:
To study the interaction between the lightning leader and the wind turbine, a 2-dimension random model of lightning leader is used to simulate and analyze the cases of lightning flash striking the wind turbine. Random simulation results demonstrate that as the horizontal distance between the initial downward leader and the turbine increases, the probability of the turbine to be stricken by lightning decreases instead, and even declines to about 4% when the distance is around 500 meters. The lightning strike points mostly are the turbine blades and there is some distinction in the striking character when the turbine is under different conditions.Here it is supposed that the wind turbine is relatively still because the rotation speed of the blade can be ignored compared with the speed at an order about 10⁵ m/s in which the downward stepped leader develops. For simplicity, the blade in the first quadrant is named as No.1 blade and the other two as No.2 and No.3 blade in the clockwise direction. Then all possible turbine states are divided into five basic ones, i.e., turbine state 1—5 when the inclination angle of the No.1 blade is 0°, 15°, 30°, 45° and 60°, respectively. When the relative angle between the No.1 blade of the turbine and the vertical frame is 45°, the upward leader initiated from the turbine blade under the influence of the downward stepped leader has an obvious longer length which reaches 221 meters, nearly 10.3% higher than the average value of all the five basic situations. Due to the randomness of the occurrence that a turbine is stricken by lightning, incidences considering all important factors have been simulated such as the turbine condition and the horizontal distance between the downward initial leader and the turbine.To study and analyze the natural lightning strike probability of the blades under different conditions, the distance value which can vary a lot is hypothesized to be only 0—500 meters. When the inclination angle of the No.1 blade is 15°—45°, the turbine will bear a little higher risk to be stricken by lightning if the horizontal distance between the downward initial leader and the turbine is smaller than 300 meters. But the probability of the turbine to be stricken is relatively much higher if the distance becomes about 500 meters, obviously higher than that of turbines under any other conditions. It can be concluded that when the inclination angle of the No.1 blade is 15°—45°, the probability of the turbine to be stricken is relatively larger.

Observation and Analysis on Qiongzhou Strait Gales of Severe Typhoon Neasat (2011)

Wang Zhichun, Zhi Shiqun, Ding Lingyun

2013, 24(5): 595-605.

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Abstract:
Based on wind data of a severe typhoon observed by two meteorological towers and one motive wind profile radar which are located on both sides of Qiongzhou Strait at the inshore sea, the gale features of the severe typhoon Neasat (2011), maximum wind speed, gust factor and wind profile index variation characteristics of typhoon Neasat (2011) are analyzed.On the right side of the typhoon path, the wind direction is clockwise on the Northern Hemisphere; the maximum 10-minute average wind speed observed in typhoon eye district is near 35 m·s^-1, and the wind direction rotation is over 180°; the maximum 10-minute average wind speed in periphery district is near 30 m·s^-1, and the wind direction around has rotated by 73°. Wind shear process can be fitted by exponential function and logarithmic function, which both fit well for smooth underlying surface, and the logarithmic function is slightly superior to exponential function.Gust factor decreases with increasing wind speed until the wind speed reaches level 6, and rougher underlying surface leads to bigger gust factor.The relation between wind gust factor and the height can be fitted by exponential function, especially when the surface is smooth.Compared with GB/T 18710—2002 recommended value, the gale shear index calculated over rough underlying surface during typhoon Neasat (2011) is higher than the recommended value, while over the smooth underlying surface it is lower than the recommended value.

Multi-model Super-ensemble Forecasts for the Circulation in August 2010

Dong Haiping, Zhang Xiuli, Guo Weidong, Yan Yan

2013, 24(5): 606-616.

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Abstract:
Based on 24—168-hour model forecast of ECMWF, JMA, German Bureau of Meteorology, CMA and China Air Force, the multi-model super-ensemble and the multi-model ensemble mean forecasts of 500 hPa geo-potential height and 850 hPa temperature from 8 August to 31 August in 2010 are conducted using fixed training period and running training period. The root mean square error (RMSE) and correlation coefficient are utilized to evaluate forecasts of the super-ensemble, the multi-model ensemble mean, and anyone of five models. Meanwhile, the distribution of RMSE about different forecasts is analyzed, respectively. The results show that ECMWF model performs the best in 500 hPa geo-potential height forecast and JMA model performs best in 850 hPa temperature forecast among five models from 24 hours to 168 hours, and the skill of super-ensemble forecast is the best of all. The super-ensemble forecast skill is improved not only in fixed training period but also in running training period, and the super-ensemble result of running training is slightly better than the result of fixed training at the end of the forecast period, and both of them are better than the result of any single model and the simple ensemble mean. But the result of simple ensemble mean has its advantage along with the forecast time. The forecast result of the whole August shows that the value of RMSE in super-ensemble forecast is the least not only in 500 hPa geo-potential height but also in 850 hPa temperature, which is the best of all forecast results, and the result of running training is better than the fixed training. But the value of the correlation coefficient is similar between the forecasts, and the skill of the simple ensemble mean is the highest of all, which means the simple ensemble mean has its advantage. The RMSE distribution of super-ensemble, multi-model ensemble mean, and any single models is quite different over various regions, the skill of super-ensemble is the best of all. The areas of skill improvement by the super-ensemble forecast in 500 hPa geo-potential height are mainly located in Indian Peninsula, Indian Ocean, the Tibet Plateau and its west. The areas of skill improvement by the super-ensemble forecast in 850 hPa temperature are mainly in Mongolia, the Tibet Plateau and Xinjiang of China and its west.

Performance Test of Five-type Photosynthetic Active Radiometers

Ding Lei, Yang Yun, Bian Zeqiang, Quan Jimei, Wang Dong

2013, 24(5): 617-624.

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Abstract:
Photosynthetic active radiometers are used to measure the solar photosynthetic active radiation. Also, it can be turned 180°, facing down to measure the photosynthetic active radiation of the ground. When it is used outdoors, the environmental condition has impacts on the performance, which may increase the measurement error. The performances of five different types of photosynthetic active radiometers are tested, such as sensitivity, cosine response, linearity, temperature dependence, spectral sensitivity and non-stability.The non-linearity errors of five photosynthetic active radiometers are all within 1%. When the irradiance is less than 250 W·m^-2, the differences of the non-linearity errors for different-type radiometers are significant. Cosine response errors gets bigger with the increase of the zenith angle (θ). When the zenith angle changes from-80° to +80°, cosine response errors of PAR LITE, LI-190 and FS-PR type radiometers are within 10%; the error of TRT-5 radiometer is within 10% just in the range of-55° to +55°; and HSC-FPH-1 is within 10% when θ is-45° to +40°. When testing the effects of temperature on photosynthetic active radiometer, the temperature coefficients of PAR LITE, LI-190 and FS-PR type radiometers are within 0.3%/℃, TRT-5 and HSC-FPH-1 type photosynthetic active radiometers are within 0.5%/℃. The wavelength range of photosynthetic active radiometer is from 400 nm to 700 nm. The ideal sensor should have clear cutoffs to light below 400 nm and above 700 nm. The spectral response of PAR LITE, LI-190 type radiometers is approximated to a horizontal line, which is closer to the ideal spectral curve. The response of FS-PR is overestimated within 400—550 nm and underestimated after that. The response of TRT-5 and HSC-FPH-1 photosynthetic active radiometers is lower than the ideal curve in the whole visible waveband. The consistency of five-type photosynthetic active radiometers with the standard value are all within 5% which is tested under solar light outside. At noon, the error is smaller as the zenith angle is small; but when the zenith angle grows bigger, the error is bigger due to the increase of cosine error. The stability for photosynthetic active radiometer in the experiment are within ±3%. Due to the limited time and samples, the stability of homemade radiometer need further test. Zero offset of photosynthetic active radiometer is very small, which could be ignored. Therefore, it is necessary to calibrate the radiometer periodically to minimize the error. The analysis and comparisons of the experiment results provide scientific basis for controlling the radiometer quality, improving the measurement accuracy and selecting instrument for meteorological observations.

Comparison of Short-term Forecast Method of Wind Power in Wind Farm

Xu Yang, Chen Zhenghong, Yang Hongqing, Wang Lin, Cheng Chi, Xu Peihua

2013, 24(5): 625-630.

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Abstract:
To further improve the accuracy of wind energy forecast and provide more valuable service, several wind energy forecast methods are studied comparatively in Jiugongshan Wind Farm. Based on the wind speed simulation results by the aggregative model CALMET coupled with MM5 (the model resolution is 200 m), the principle method and dynamic-statistical method are used to discuss 24-h forecast effect, with the temporal resolution set to 15 minutes. There are three kinds of principle method to discuss the effect of simulated wind speed correcting and the wind energy forecast model based on observations. The dynamic-statistical method forecast by establishing a rolling model using the simulated data of last period every day.The fine-scale simulation can obviously forecast the variation trend of wind speed. The correcting of simulated wind speed can effectively reduce the wind speed error and improve the forecasting accuracy, but it is difficult to revise the changing trend of simulated wind speed.The dynamic-statistical method is much more suitable for the complex topography mountainous terrain, and the monthly relative mean square root error is 14%—26% from July to December in 2011, which might be the result of its spontaneous adaption for terrain conditions.The wind energy forecast model based on observations is better than those based on theoretical model and can effectively reduce the forecasting error, because the wind farm environment has unique effects on the output power of fan.Furthermore, it is discovered that the wind energy forecast in southern mountain area is much more difficult than in north area. The fine-scale simulation should be used to reduce the infection of terrain; the method of simulated wind speed correcting must consider the different situation of the wind farm; the extreme weather events must be considered, and effects of different weather especially meteorological disaster such as ice-coating and thunderstorm should be deeply studied. These results enhance the service effect at Jiugongshan Wind Farm in Hubei Province, and more research should be carried out to improve the forecast accuracy.

Designing and Implementation of Climate Interactive Plotting and Analysis System

Wu Huanping, Zhang Yongqiang, Sun Jiamin, Shao Pengcheng

2013, 24(5): 631-640.

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Abstract:
Climate Interactive Plotting and Analysis System (CIPAS) is an ongoing application project for the modern climate monitoring, diagnosis and prediction operation launched by China Meteorological Administration since 2011, which has enhanced the capability of climate data retrieval, multi-visualization, diagnosis, statistics, and products generation. CIPAS provides an integrated data environment that contains meteorological surface observations, index data, reanalysis data and numerical forecast products with long time series. The data environment also implements the simple and unified application program interface (API) with parameters in data property of element, level, time, spatial region, and data type and so on. A distributed architecture with multi-ties and a light client are designed for CIPAS, which allows procedures with massive computing and backend production generation to run on the server. The component and plugin design patterns are used to implement the core components of CIPAS client. The CIPAS core components mainly consist of data accessing, graphic rendering, climate diagnosis and analysis, page layout, setting, and these components can be constructed into the basic operational features and the tool box of climate analysis as well, for instance, EOF, SVD and so on. Also, it can be used to encapsulate APIs for extension application. The construction principle, general system framework, main features, deployment and workflow of CIPAS are discussed in detail. Meanwhile, some key issues involving the implementation of the CIPAS are further discussed, such as data management, graphic rendering engine and related algorithms, production automatic generation, distributed and asynchronous communication mechanism, crossing platform, development API, and plug-in for toolbox. The data type, the accessing API and data exchange format are introduced in data management section. The graphic renderer engine involves OpenGL implementation. Production generation uses workflow engine for automation and customization. Distributed communication is implemented using ICE open source component to avoid different client and server deployment environment. C++ and JAVA language is adopted to ensure crossing platform compatibility. Plug-in implementation covers the component and interface technique. In terms of operation application, two typical operation scenarios are introduced in detail. One case focuses on how to get the given climate diagnosis result using multi-tool in toolbox, and the other case explains how to get the monthly station forecast production both with graphic and text format by using several interactive tools. The pilot using of the current system for the national and provincial operation offices present that CIPAS meets the basic operational requirement and shows the operation and development prospect of CIPAS features. Some advancing directions are also proposed for the further development of CIPAS.

Vol.24, NO.5, 2013