应用气象学报

CHARACTERISTIC ANALYSIS OF CHINA DUST STORM IN 2002

Fang Zongyi, Wang Wei

2003, 14(5): 513-521.

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Abstract:

Dust storm in China of March-April in 2002 is studied on its frequency, together with the monthly and pentad circulation pattern, using surface observation and NCEP/NCAR reanalysis. It shows that it is the development and intensification of East Asian trough, a prevailing circulation pattern over the north, northeast even central China, that result in the more occurrence of dust storm along near northern track. The sub cold front developed by the maintenance of the northeast cyclone could bring up strong local dust storm. Further analysis of sand and dust transportation in the northeast cyclone weather pattern gives the spatial distribution of the dust and sand along the track of dust storm in the light of GMS-5 TBB data. It indicates that strong dust storm could develop to the northeast, influencing on the area of northeast, for East, even further north, in the case of strong northeast cyclone.

OBJECTIVE VERIFICATION ON NUMERICAL OPERATIONAL FORECASTING SYSTEM IN BEIJING

Chen Min, Wang Yingchun, Zhong Jiqin, Zhang Chaolin

2003, 14(5): 522-532.

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Abstract:
Structure and methods of the objective verification system on operational numerical weather forecasting in Beijing area are introduced in detail. On the base of the analyses on verification results of main forecasting products in the winter of 2001 (from 1st Nov. 2001 to 28th Feb. 2002), the characteristics of error distribution of operational numerical forecast in Beijing area are shown. In addition, the systematic and non-systematic errors' possible sources in operational numerical forecast are analyzed. It suggests that the Bias errors revealed by grid verification appear to reflect the influence of topographic features on surface and mid-troposphere variables forecasts. Also, for upper-air forecasts, nonsystematic error caused by inconsistent resolution of scales between the forecasts and observation is a more important component. The initial errors usually propagate into the forecast. Utilizing a simple mean error correction could eliminate part systematic error.

IMPACT OF THREE DIMENSIONAL VARIABLE CONFIGURATION SCHEME ON SIMULATION OF INERTIA GRAVITATIONAL WAVE WITH DISPERSION PROPERTIES

Zhu Hongwei, Liu Yudi

2003, 14(5): 533-541.

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Abstract:
In the framework of linear baroclinic primitive equations, calculation is undertaken for dispersion of inertia gravitational waves in different kinds of 3D (three-dimensional) grids from the perspective of frequency and group velocity, and the reason of the deviation in various grids is analyzed. The results indicate that such 3D structures as C/CP (horizontal grids with Arakawa C grids, and vertical with Charney-Phillips) and Z/LZ (horizontal grids with Z grids, and vertical with LZ) are superior to others in the computational dispersion properties, thereby providing a guidance to the selection of 3D grids applicable to atmospheric primitive equation models.

A STUDY OF THE VARIATION AND TENDENCY OF SURFACE DRY-AND-WET STATE OF NORTHEAST AREA IN CHINA

Sun Li, Shen Baizhu, An Gang

2003, 14(5): 542-552.

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Abstract:
Based on the 80 observation station's data of monthly precipitation and mean monthly temperature over the northeast area in China from 1961 to 2000, the maximum potential evaporation, the aridity index and the water budget in the surface are computed. The spatial and temporal distribution and the variation and tendency of the surface dry-and-wet status over the northeast China are analyzed, and the relationship between the dry-wet status and precipitation and temperature is examined. The results show that not only the surface aridity index have a large interannual and decadal variation, but also have an obvious phasic change and low frequency variation characteristics. Since the mid of the 1990s, the northeast area in China shows the arid tendency obviously, and it is mainly controlled by the higher temperature which caused the potential evaporation increasing greatly.

SEASONAL VARIATION FEATURES OF 500 HPA HEIGHT IN NORTH PACIFIC OSCILLATION REGION AND ITS EFFECT ON PRECIPITATION IN NORTHEAST CHINA

Liu Zong xiu, Lian Yi, Shen Baizhu, Gao Zong ting, Tang Xiaoling

2003, 14(5): 553-561.

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Abstract:
By using of the China National Climate Center (CNCC) 500 hPa monthly mean height data (10°×5°) from 1960 to 2000 and EOF, SVD methods, the 500 hPa seasonal variation characteristics of the 500 hPa height field in the North Pacific Oscillation (NPO) region (25° to 70° N, 140° E to 150° W) region and its relation with precipitation in 80 stations over Northeast China are analyzed. The results show that: (1) In winter, the spatial structure of the first loading vector of the 500 hPa height field in NPO, similar to the positive phase of the surface pressure oscillation, is of a "﹣, +" wave distribution from north to south with the variance contribution ratio being 40%. This is a basic general circulation mode in the mid-high latitudes of North Pacific in 40 years with the East Asia Trough being a stationary wave, and it is also the main cause that NPO is mostly in positive phase. Otherwise, it is similar to the negative phase of the surface pressure oscillation. The second loading vector is of a whole "+" value distribution with the variance contribution ratio being 28%. This mode is an abnormal pattern opposite to the climatic basic mode, a long-wave ridge as a substitute for the East Asia trough. In summer, the first loading vector is of a whole "+" value distribution with the variance contribution ratio being 30%; the third is of a "+, ﹣" wave train from north to south with the variance contribution ratio being 13%. This indicates that the summer 500 hPa height NPO is not the main mode. There is a clear NPO mode in both spring and autumn. (2) There is significant correlation between the 500 hPa mean winter height field in the NPO region and summer precipitation over Northeast China (>0.01) with a "+, ﹣" wave train from north to south. The first SVD singular vector has a variance contribution ratio of 49%. The summer precipitation over Northeast is above the normal when the 500 hPa height field in the NPO region in the previous winter is in negative phase, but it is dry when the 500 hPa height is in positive phase. There is similar relationship in other seasons.

IMPROVED NDVI of FY-1C CAVHRR

Gu Songyan, Fan Tianxi, hang Wenjian, Yan Jing

2003, 14(5): 562-567.

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Abstract:
An analysis of the NDVI and the calibration coefficients used to describe sensor degradation in Channel 1 of the Chinese Advanced Very High Resolution Radiometer (CAVHRR) boarding on the FY-1C spacecraft are presented. The radiometrically stable permanent sand of Dunhuang is used as a target to characterize sensor performance, and remote sensing data of CAVHRR over Dunhuang during 3 years was used. The analysis results show that the degradation in Channel 1 of FY-1C made the distribution of FY-1C NDVI all over the world fuzzy and cannot show the situation of canopy growing. Corrected model for NDVI and califuzzy and cannot show the situation of Channel 1 of FY-1C CAVHRR constructed from Dunhuang reflectivity and NDVI database can improve the FY-1C global NDVI distribution. The relationship improving with time for NDVI and calibration coefficients for Channel 1 of FY-1C was derived from this researching work. The improved new calibration coefficients for CAVHRR Channel 1 have a great correspondence with the results of CRCS is 2000. It is recommended that the derived model and coefficients are helpful to improve the quantity application of FY-1C global remote sensing data.

ECOLOGICAL AND ENVIRONMENTAL CHANGE INVESTIGATION THROUGH REMOTE SENSING AROUND LONG YANGXIA RESERVOIR, QINHAI PROVINCE

Li Fengxia, Xu Weixin, Zhou Bingrong, Zhang Juan

2003, 14(5): 568-573.

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Abstract:
Using American Landsat ETM, TM imagines data, the ecological and environmental change investigation through remote sensing in the region around Longyangzxia Reservoir in 1987 and 2000 was carried out. The results show that around the Longyangxia Reservoir region, the physiognomy can be divided into 19 categories, of which the areas and distributions have been found out. The analysis of the dynamic changes in ecology and environment from 1987 to 2000 around the region of Longyangzia Reservoir indicates that the areas of water, dene and natural grassland are all changed. The areas of rivers and lakes decreased by 9.78 km² and 4.82km² respectively. Up to 2000, the most part of the riverbeds was bare; Qiabuqia River had been dried out; and almost all the lakes in this region had shrunk to some extent. The distributions of the sand lands had the same changes mostly; its area increased by 5.08 km² annually; and the sporadic sand hills have joined together into large-scale dense sand hills. The total area of the grasslands decreased by 59.47 km², and its annual degreesive rate was 0.35%.

REVIEWOF THE PROGRESS IN METHODS OF AGROMETEOROLOGICAL DISASTER PREDICTION IN CHINA

Wang Shili

2003, 14(5): 574-582.

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Abstract:
Investigation of the progress in methods of agrometeorological disaster prediction in China in recent years is made, some new methods and techniques are introduced, and some comments are presented. It is concluded that: ① At present the statistical models are the major approaches to predict the agrometeorological disasters; recently some new methods and techniques are used, including improvement of statistical models, combination between climate models and agrometeorological models as well as application of crop growth simulation models. In general the research of agrometeorological disaster prediction is not very satisfied. ② Attention should be paid to determination of index, physical mechanism and agricultural meaning of predictors and processing methods of mathematics models, as well as prediction method based on crop simulation models. ③ It is the effective approach for agrometeorological disaster prediction to synthesize different disciplines, multi-prediction methods, multi-time scale of predictions and to combine prediction models with monitoring information by remote sensing. The operational early warning system of agrometeorological disaster prediction should be set up.

A PREDICTING DROUGHT MODEL WITH AN INTEGRATION OF MULTI-SCALE IN NORTH CHINA

Wei Fengying

2003, 14(5): 583-592.

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Abstract:
Based on the significant interdecadal and interannual variations of the drought in North China, a new modeling technique of the drought prediction is proposed, i. e., the drought change is regarded as a composition of the interdecadal variation, the interannual variation and a noise. The technique is composed of modeling both the climate trend, to be represented with the interdecaeal variation, and the interannual variation plus the antecedent strong signal. The sum of predictions made with two models is taken as a final prediction of the drought. The prediction experiments for winter, spring, summer and autumn with one to two seasons ahead are made. The results show that the modeling technique can catch the change in drought well in North China. The prediction model differs from the previous modeling, which based on computing correlation between the drought index and the atmospheric and oceanic elements, then considering the correlation be invariable. Hereby the concept of dynamic strong signal is suggested, it is the observation series in some regions where the remarkable difference between the recent atmospheric and oceanic anomaly and the multi-year mean occurs. The strong signals varies with different years in which the serious drought occurs, and their spatial, positions and intensities varies too. An extra season hind cast for 1996 to 2002 shows that the modeling is capable of fitting the drought trend and exhibits a higher prediction skill.

A DROUGHT PREDICTION MODEL IN NORTH CHINA PLAIN AND ITS APPLICATION

Liu Jiandong, Wang Futang, Yu Qiang, Wang Jianlin, Bi Jianjie, Fan Guang hua

2003, 14(5): 593-604.

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Abstract:
A drought prediction model in North China is developed based on the response curve of phototsynthesis rate of winter wheat to water stress and the concept of agricultural drought stress index and of agricultural drought early warning index. The results of simulated agricultural drought for 432 dekads in 1998—2000 for Beijing, Shijiazhuang, Zhengzhou and Jinan show that the accuracy of agricultural drought trend prediction is 90.7% and the accuracy of agricultural drought quantitative prediction is 87.5%. In addition, the model is able to predict drought in a region. The model is applied to a numerical analysis for agricultural drought in 1961—2000 in Beijing. The results show that agricultural drought occurs nearly every year under normal climatic condition in Beijing, especially the severe drought occurs in the period from grain filling to maturity of winter wheat. But the severe level of drought stress in each year is different, there is a 3—6 cycle according to the power spectrum analysis. According to the temporal and spatial analysis for agricultural drought in North China under normal climatic condition, it is found that the agricultural drought stress indexes strengthen gradually from flowering, grain filling to maturity of winter wheat in North China. It conforms to the fact of agricultural production in North China.

SPATIAL INTERPOLATION METHODS OF DAILY WEATHER DATA IN NORTHEAST CHINA

Zhuang Liwei, Wang Shili

2003, 14(5): 605-615.

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Abstract:
Aimed at requirement for daily weather data with high resolution which is used to scaling up the crop growth simulation models, the spatial interpolation methods of daily weather data from April to October in Northeast China are studied using ordinary Kriging and other two relatively simple methods: inverse distance weighting (IDW) technique with weighting of longitude and latitude, and gradient of height plus inverse-distance-weighting (GIDW) technique. The statistics analysis for interpolated values and cross verification for estimated values are made. The results indicate that for temperature, the precision of the evaluated value is the highest, and the smoothness is moderate, in addition, the space distributing trend of the interpolated result is more close to the actual data using GIDW method. For precipitation, the precision of the evaluated value with IDW method is higher than that with the Kriging method, and the smooth level of the interpolated result is smaller, and it is more fit to the interpolation of the daily precipitaion. The cause of the higher precision of the vealuated values with GIDW and IDW methods is that the obvious season changes in longitude, latitude and sea-level-elevation gradient of the daily maximum temperature, minimum temperature and precipitation are considered, the weights in longitude and latitude for meteorological factors are determined, and the meteorological factors are also corrected by daily sealevel-elevation gradient.

STUDY OF LOW TEMPERATURE DAMAGE PREDICTION APPLICATIONS IN EN, CHINA BASED ON A SCALING-UP MAIZE DYNAMIC MODEL

Liu Buchun, Wang Shili, Zhuang Liwei, Lu Zhiguang, Song Yong jia, Shi Xueli

2003, 14(5): 616-625.

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Abstract:
A scaling-up maize dynamic model in EN, China is established, including an improved heat unit development model and crop parameters in the certain regions based on the maize field experiments data and predecessors' studies on crop simulation models. The development and growth processes are simulated for 12 stations using daily weather data for 40 years (1961—2000). The index for low temperature damage is defined by the days of tasseling postponed. The years with low temperature damage and the related reduction of yield are analyzed using the index. The development and growth processes in the grids with 0.25o×0.25o are simulated for the year with typical low temperature damage and for mean climate condition in 40 years. The experiment on prediction method of low temperature damage using maize simulation model combined with regional climate model is carried out. The main conclusions are as follows: (1) The model of development stage well simulates maize development stages and the response of development stages to low temperature damage. Using the index for low temperature damage defined by the days of tasseling postponed, the degree of low temperature damage is estimated. The results are very well and are conformed by historical cases. (2) The model can basically simulate responses of maize biomass to low temperature damage; but the parameters of cultivar should be calibrated by more measured experiment data, and the model will be modified further. (3) It is a resolution to scaling-up application of crop models to determine the crop parameters in these areas and to apply GIS. (4) The method for scaling-up maize dynamic model is of more mechanism and explanatory. Running maize model, according to low temperature damage index and output of regional climate models, it is easily to simulate and predict occurrence degree of low temperature damage.

FORECASTINGMODELS OF HEAT INDEX FOR CORN IN NORTHEAST CHINA

Guo Jianping, Tian Zhihui, Zhang Juanjuan

2003, 14(5): 626-633.

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Abstract:
Using the mean monthly air temperature from 1961 to 2000, the corn heat indexes in 3 provinces and whole Northeast China are calculated. Based on the statistic analysis between heat index and atmospheric circulation data, 6 models of forecasting availably the corn heat index are set up. Each model can be used to forecast heat status in the growth and development period of corn in each province and whole Northeast China. Test shows that the accuracy of all models is higher and the stability is preferable. The mean relative error of 6 models is lower than 7%. These models show the better forecasting ability. In which, the least relative error is in Liaoning Province, the mean value is lower than 2%, and the forecast effect is best. The greatest relative error is in Heilongjiang Province, the mean value is from 4.5% to 7%.

A PHENOLOGICAL MODEL TO SIMULATE RAPE DEVELOPMENT

Liu Hong, Jin Zhiqing

2003, 14(5): 634-640.

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Abstract:
A dynamic simulation model for rape phenological development is established according to rape physiological and ecological theories and the quantitative relationship between rape phenological development and the environmental factors. The "wheat clock model" in WCSODS and the vernalization model in CERES-wheat are used for reference. A three-year experimental data set is partially used for modification and determination of the genetic parameters for 2 cultivars and partially for validation of the model. The simulated errors are the compared with the accumulated temperature method. The results show that the average errors are within 1 day for different development period, and the standard errors are within 2 days for whole developmental duration.

Vol.14, NO.5, 2003