应用气象学报

A Cloud Parameters Retrieval Algorithm and Cloud Characteristic Analysis over East Asia in 1991

Fang Zongyi, Liu Yujie, Zhu Xiaoxiang

1994, 5(2): 135-142.

[FullText](2494) [PDF 471KB](1357)

Abstract:
According to the requirement of the International Satellite Cloud Climate Project (ISCCP), a cloud parameters retrieval algorithm is designed, which is fit to derive cloudiness over East Asia and the Tropical Ocean area. The satellite data is obtained from original S. VISSR of GMS-4, ranging from 50°N—30°S and 80°—175°E, and covering the midseason months—January, April, July and October of 1991.The total monthly mean cloudiness and hourly mean cloudiness are calculated with the method mentioned above. The results are examined by comparing with OLR climatological data in the periods. Furthermore, not only the seasonal variations in cloudiness, such as monsoon surge cloud system and the latitudinal movement of the ITCZ, but also seasonal distribution and the diurnal variability of cloudiness are studied in the region by using the results.

Computation of the Finite Difference Quotient in Longitude on a Uniform Longitude-latitude Grid in High-latitudes

Liao Dongxian

1994, 5(2): 226-229.

[FullText](3195) [PDF 145KB](1039)

Abstract:
In consideration of small time step or Fourier filtering having to be taken in the integration of thee grid model in high-latitudes due to the convergence of the grid points near the poles, a difference scheme has been presented, which can avoid such difficulties mentioned above. The scheme can be constructed on the basis of any given finite difference scheme. It is the same as the latter in form, but requires that the grid-length used should be adjusted so as to let the time step to be as large as the one used in midlatitudes and the computational stability criterion to be satisfied. In computation it is convenient and there is nearly no extra operational amount. Furthermore, if the original scheme is mass-or-energy-conserving, the new scheme also has such a property.

The Environment of Meso-scale Phenomena with Brightness Temperatures from TOVS/MSU-channel 2

Han Weiqing, Wang Zonghao

1994, 5(2): 242-247.

[FullText](3249) [PDF 321KB](1103)

Abstract:
This note describes the preliminary use of brightness temperatures of TOVS/MSU-channel 2 on board the satellite NOAA-11 to show the characteristic environment of meso-scale phenomena which arise alternately the convective precipitation process over the region (20o―40 o N; 90 o―110 o E) on 7―12 July 1989.The preliminary results are: (1) The brightness temperatures of the MSU-channel 2 contribute to the 700 hPa level of peak energy. It is possible to provide a certain characteristic environment of the meso-scale phenomena over the above mentioned region. (2) Cloud clusters with strong convection emerge possibly in a transition zone from the low value of brightness temperatures to the relatively high value, and rather strong precipitation appears near the high value zone

A NOAA-AVHRR Satellite Data Process System and Its Application to Monitoring Ecological Environment

1994, 5(2): 248-252.

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Abstract:
The NOAA-AVHRR satellite data process system was developed in Zhejiang Institute of Meteorology. A brief introduction about the design, system structure and the main technical key points is given in the paper. The emphasis was put on the three dimentional stereoscopic image displaying of the system software and its application to monitoring vegetative ecological environment.

A Laboratory Study on the Role of the Loess Particles as Natural Ice Nuclei

Feng Daxiong, Chen Ruzhen, Jiang Gengwang

1994, 5(2): 129-134.

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Abstract:
The ice nucleating effectiveness of the loess particles has been tested by directly dispersing them in cloud chamber. Their effectiveness can reach up 4×106 per gram at －15℃. From these results the high ice nuclei concentration observed during dust storms could be explained. It is considered that the airborne dust particles from the Loess Plateau of China would provide abundant ice nuclei for the downward area.

Relationship Between OLR Low-frequency Oscillations and the Formation of Typhoon over the Western Pacific

Xie An, Ye Qian

1994, 5(2): 143-150.

[FullText](3184) [PDF 487KB](1730)

Abstract:
The composite analyses were completed of the 30–60 days filtered OLR data during the six years of 1975—1977 and 1979—1981 based on the evolution of the average OLR over West Pacific where typhoon generates frequently. The results show clearly that the systems concerning the typhoon formation are mostly located over the low latitude regions in the Eastern Hemisphere (to the east of 60°E). Some clear characteristics are found for the different stages, i., e. the frequency formation, the intermission of typhoon and the transition stage, respectively. These results will be useful to the medium range forecast of the typhoon formation.

Manufacture of the Large Weighing Lysimeter

Ke Xiaoxin, Lin Rinuan, Xu Guochang Peng Suqin, Yang Xingguo, Zhang Xudong

1994, 5(2): 151-157.

[FullText](3321) [PDF 352KB](1343)

Abstract:
A large weighing lysimeter installated in Dingxi comprehensive testing station is introduced. It has an efficient evapotranspiration area of about 4.0m 2, an undisturbed soil depth of about 2.6 m and a measuring accuracy of 0.1mm. It is the first large weighing lysimeter employed in meteorology in China

A Reformed Global Climate Model Extended from Troposphere up to Stratosphere

Mo Wentao, Li Weiliang

1994, 5(2): 158-167.

[FullText](2967) [PDF 445KB](1285)

Abstract:
Using Arakawa’s “σ‐p” coordinate, a two-dimensional global tropospheric model was reformed and extended up to stratosphere in the vertical level. The developed model not only has good stability in computation, but also the good performance to simulate the general feature of the mean temperature, mean zonal and meridional motion and their seasonal variation. It is also proved that the extension of the vertical level onto the stratosphere in a general circulation model is able to improve the description of the upper tropospheric circulation

Relationship Between the El Nino and Precipitation Patterns in China Since 1500 AD

Zhang De'er, Xue Zhaohui

1994, 5(2): 168-175.

[FullText](4432) [PDF 446KB](1653)

Abstract:
Based on the historical El Nino records and the yearly dryness/wetness grade data in China during the 1500—1990 A. D., the composite dryness/wetness grade charts of El Nino year, and the first non-El Nino year after ending the El Nino event for 101 cases have been done, respectively. They show the deficient rain areas are distributed in the regions of Inner Mongolia—Gansu Provinces and the Lower-Middle Changjiang River, and the plentiful rain areas in Northeast China, Huang-Huai River region and Guangdong coastal area for the El Nino years. In the first non-El Nino year after ending the El Nino event, the precipitation pattern is almost opposite to that in the onset year. For the total 9 cases occurred in the 1951—1990, the distribution of plentiful rain areas and deficient rain area appears to be similar to that on the composite charts of 101 cases for the last 490 years, whether in the onset year or in the first non-El Nino year. Furthermore, the composite charts for each century show that some main features are still similar to that for 490 years. So, the common distributive features mentioned above appeared in the past 490 years, 40 years and each century can be considered as the typical precipitation pattern correlated with the El Nino events in the eastern China.

Field Tests and Measurement Accuracy of Automatic Weather Stations (AWS)

Guo Xiqin, Zheng Shu ''er, Wang Jinzhao

1994, 5(2): 176-183.

[FullText](3311) [PDF 359KB](1123)

Abstract:
Based on the computed correlation coefficients and the error of the differences between the tested values from AWS and the conventional observations, the reliability of the comparative tests were demonstrated. A method of calculating the standard deviation, qualified rate and accuracy of the AWS measurement results were suggested. The hidden periodic analysis and autocorrelation model were used to compute the AWS measurement data. The results show clearly that some measurement parameters from AWS are better than the man-made observations

A Study on Climatic Characteristics of Hainan Island by Using Meteorological Satellite Data

Wang Xuanji, Dian Changgong

1994, 5(2): 184-189.

[FullText](3953) [PDF 299KB](1484)

Abstract:
Using NOAA polar-orbiting meteorological satellite data, the distribution and the changes of the underlying surface reflectance, vegetation index, underlying surface temperature and outgoing longwave radiation (OLR) are studied under the condition of cloud-free in both dry and wet seasons in Hainan Island. It is proved that the application of satellite data is highly effective to the study of underlying surface regime, which is one of the important factors for the local climate.

A Preliminary Analysis of the Cross-Equatorial Flows During the Northern Winter Monsoon

Li zengzhong, Zhou Jiangxin, Yang Linmei

1994, 5(2): 190-195.

[FullText](3547) [PDF 296KB](1354)

Abstract:
By using the grid wind data from 1980 to 1986, the eastern Hemisphere cross-equatorial flow channels in the lower and upper troposphere during the Northern winter monsoon (Dec.—Feb.) are investigated. It is found that there are five channels in the lower troposphere in the region mentioned above. They are located at 105°E, 125°E, 45°E, 80°E and 150°E, respectively, with the main zone between 100°E and 130°E. In the upper troposphere, the main channels of the cross-equatorial flows are located in the region of 80°―120°E. During both winters of 1983―1984 and 1984―1985, it is found that there exists a strong cross-equatorial flow from north at the channel of 45°E, which is associated with the persistent high-latitude blocking pattern occurred at 500 hPa over the eastern Atlantic Ocean and also with the more frequent genesis of the tropical storm over the southern Indian Ocean and southern Pacific Ocean. Additionally, the analyses of the mean meridional cell indicate that there is a complete winter monsoon circulation in the region of 80°―125°E during the Northern winter monsoon

Determining Optimum Order of Autoregressive Model and the Application to Long-range Forecast

Hu Jifu, Jiang Hongchuan

1994, 5(2): 196-202.

[FullText](4776) [PDF 300KB](4173)

Abstract:
The methods of determining the optimum order of autoregressive (AR) models, such as FPE, AIC, BIC, L1and L2 were summarized and tested by using the monthly mean temperature data in Qingdao. The selected orders of the AR model by use of the FPE, AIC and L1 criteria are the highest, medium by L2 and the lowest by BIC, respectively. Additionally, a recurrence method of AR model was suggested to forecast the monthly mean temperatures in Qingdao. It has been proved by the forecast practice that the low order AR model from the BIC criterion is more efficient

The Effect of Climatic Change of Cold or Warm on Agricultural Environment over the Lower and Middle Reaches of Changjiang River in the Last Century

Zhang Yangcai, Tan Jianguo

1994, 5(2): 203-210.

[FullText](3102) [PDF 414KB](1750)

Abstract:
The variable features of the heat in the growing period (daily mean temperature ＞10℃ accumulated temperature and its durable days) and the low temperature in the overyearing period (daily minimum temperature ＜0℃ negative accumulated temperature and the extreme minimum temperature＝ in Shanghai, Hefei, Jinhua, Wuhan, Changsha, Nanchang, Ji’an and Hengyang stations are analyzed, respectively. Using the spectrum analysis, the climatic cold or warm variable periodicity and the long-range fluctuation tendency are found over the lower and middle reaches of the Changjiang River, Furthermore, in view of the climatic prediction and forecast, it is shown that the anomalous change of the cold or warm may be a potential threat of establishing a modern agriculture system of high yield, excellent quality and high efficiency in the end of this century. So, in order to construct a new agricultural ecological systems with high control power of climatic change, it is necessary for paying attention to “the climatical input”, surmounting the traditional agricultural experience, and improving the crop cultivation and rotation systems.

A Preliminary Study of the Surface Heat Balance in Shanghai

Ju Xiaosheng

1994, 5(2): 211-217.

[FullText](2700) [PDF 316KB](1297)

Abstract:
On the basis of the observed data of surface heat balance and conventional climatic data from 1961 to 1965 in Shanghai, the diurnal, monthly and annual variations of various heat balance elements are analyzed, respectively. The results illustrate that the latent heat is dominant in the process of land surface heat balance in the moist climate regions of China

Relationship Between the Variations of East Asian Winter Monsoon and Temperature Anomalies China

GuoQiyun

1994, 5(2): 218-225.

[FullText](4804) [PDF 422KB](2432)

Abstract:
The variations of East Asian winter monsoon during the last 40 years period (1951—1990) were studied, the relationship between winter monsoon activities and temperature anomalies in China was examined. The winter monsoon was characterized by two indices: IWS and IWE. IWS represents the intensity of winter monsoon. IWE reflects the extent of southward extension of winter monsoon along the eastern coast of Asian continent. The power spectrum analysis shows 11.0 a and 2.2 a periodicity in the variations of IWS, and 7.3 a and 3.1 a periodicity for IWE, respectively. IWS negatively correlates to the winter temperatures over China except in the south-west highland regions. IWE also negatively correlates with the winter tempertures in China, but significant correlations were concentrated in a region shaped like U capital, which begins from the eastern coast, goes to the south, then turns to the west and goes to the upper reaches of the Changjiang River. But IWE does not always vary parallely to the IWS. For example, the mean anomaly of IWS in 1950’s was positive, but negative for IWE. So, the temperatures were lower in North China, and higher in the U-shape region than the normal in 1950’s. On the contrary, in 1980’s the mean anomaly was negative for IWE, and positive for IWS. Therefore, the general warming covered the whole North China, but the temperatures were relatively low in the U-shape region.

The Influence of Westerlies High Frequency Fluctuation on the Looping Track of Typhoon Yancy

Hu Jian, Chen Xuefeng

1994, 5(2): 230-234.

[FullText](4638) [PDF 255KB](1444)

Abstract:
By using the SOECTRUM-90 data and T42L9 grid data from National Meteorological Center, the looping process of Typhoon Yancy is studied. The result shows that the westerlies high frequency fluctuation (with a period of about one day) and the propagating process would exert important influence on the looping track of Typhoon Yancy

The Division and Variation of Temperature in Northwest China

Yao Hui

1994, 5(2): 235-241.

[FullText](3432) [PDF 365KB](1696)

Abstract:
Based on the annual and seasonal mean temperature data of 135 stations over the five provinces in Northwest China during the period of 1960 to 1990, the distribution of annual mean temperature is divided into four regions with the significance level of 0.001 by the fuzzy classification method. They are the north part of Xinjiang; the most parts of the area in Northwest China; the Qaidam basin; and the upper streams of Yangtze and Yellow Rivers, respectively, Furthermore, the temperature sequences of the year, winter and summer for the four areas are set up, and the variation of temperatures for the recent several decades in Northwest China is analysed

A Preliminary Analysis on Response of Tree-ring Density to Climate in the Qinling Mountains of China

Wu Xiangding, Shao Xuemei

1994, 5(2): 253-256.

[FullText](3254) [PDF 176KB](1751)

Abstract:
By using densitometry analysis, the maximum and minimum tree-ring density chronologies have been developed from four sites in the Qinling Mountains of China. It is shown that the density variation responds to the climatic change significantly. The density chronologies can be used as substitute data which indicate past local climate in the mountains

Vol.5, NO.2, 1994