应用气象学报

The Observation Experiment of Atmospheric Refractive Index Turbulent Structure Constant

Zhang Xu

1994, 5(1): 19-26.

[FullText](5052) [PDF 385KB](1191)

Abstract:
Based on the model set up by WPL, NOAA USA for an estimate of the refractive index turbulence structure constant, with the help of numerical experiment, comparison with the radar observations and adjustment, a practical model for estimating is developed. The results agree with the radar observations very well.

The Relationship Between Anomalous Trough over East Asia and El Nino

Yang Guiying, Zhang Yan

1994, 5(1): 114-118.

[FullText](3443) [PDF 202KB](1260)

Abstract:
Based on statistical analysis, an interesting fact is revealed that in winters prior to El Nino (La Nina) events occurred through 1951—1987, East Asia trough is weaker (stronger) than in the normal years. The composited field of 500 hPa height anomalies for 10 winters prior to El Nino events also shows significant positive anomalies over East Asia. The results of power spectrum and cross spectrum analyses indicate that the relationships between the trough intensity and the SST of the eastern equatorial Pacific are obvious. Both the trough and the SST in seasons have the most significant 3—4 year period oscillation, respectively, and the oscillation of the trough precedes that of the SST by 4—8 months

The Variations of Circulation Pattern in the Northern Hemisphere and Climate Change in China During 1981—1990

1994, 5(1): 1-10.

[FullText](3846) [PDF 480KB](1432)

Abstract:
The time series of annual frequency of the circulation patterns W, C, E in the Northern Hemisphere and annual mean temperature of Beijing (TB), Shanghai (TS) and the whole country (TC) in the period of 1981—1990 are expanded by a long-term tendency, a periodic function and a random function. The coherence between circulation and temperature are calculated and analyzed. The abrupt changes of circulation and temperature in the last 100 years are revealed by the methods of the accumulated anomalous curves, the signal/noise ratio as well as the Mann-Kendall test. The correlations between anomalous circulation and climate are discussed with some explanations.

The Climatic Features of Atmospheric Aerosol Turbidity Parameter over Beijing

Yao Peizhen, Zhang Qiang

1994, 5(1): 11-18.

[FullText](3093) [PDF 361KB](1765)

Abstract:
Based on the data of daily direct solar radiation during clear days from 1958 to 1989 over Beijing, the atmospheric aerosol turbidity parameters β over this area are calculated. And by combining the results above with the data of coal consumption of the market, weather conditions and volcanic eruptions, the features of annual and interannual changes ofβ and their causes are estimated. The results show that the maximum values ofβ occur in spring and the minimum in the season between autumn and winter; the values ofβ from 1958 to 1997 changed slowly and maintained a range of values between 0.08 and 0.12; after 1978 the values increased rapidly. And generally, the values ofβ in the heating seasons are smaller than that in the other time.

The Characteristics of Atmospheric Turbidity and Sand and Dust over Heihe Basin Desert and Gobi Area

Wen Jun

1994, 5(1): 27-33.

[FullText](2645) [PDF 343KB](1547)

Abstract:
The characteristics of atmospheric turbidity over Desert and Gobi area where there is special boundary layer are summarized by calculating and analysising atmospheric turbidity in summer 1990. In terms of the variations of the coefficient of atmospheric turbidity β and wave-length index α, the optical thickness, the genesis and dissipation of the atmospheric sand and dust are discussed. Furthermore, using the methods from Volz. and Arao. the contents of sand and dust in the local atmosphere under the conditions of different weather are roughly estimated

Agriculture Meteorological Decision Making Service System for Rice and Wheat

Tao Bingyan

1994, 5(1): 34-40.

[FullText](3520) [PDF 357KB](1315)

Abstract:
RMAMDSS is a perfect policy making system about agriculture meteorology, it has mainly four functions: crop-yield forecasting; crop-climate evaluation; crop-growth numerical simulation; Seedling-growth-condition diagnosis. The paper gives a detailed description of its principle, structure and function features.

Non-linear Normal Mode Initialization and Its Effect on Data Assimilation and Forecasting

Shen Yuanfang

1994, 5(1): 41-48.

[FullText](2684) [PDF 359KB](1491)

Abstract:
The non-linear normal mode initialization (NNMI) for a spectral model of mediumrange NWP in NMC, SMA is described, and its effect on data assimilation and forecasting is discussed. It is experimentally shown that in terms of two iterations by using first five vertical modes, a balanced initial field appropriate to data analysis is obtained. It also shows that NNMI is highly successful in eliminating the spurious high frequency gravity wave oscillation in forecasting, therefore, it plays an important role in improving data assimilation and model forecasting.

A Diagnostic Study of Budget of Potential Vorticity for Cold Wave-related Anticyclone in East Asia

Zhang Peizhong

1994, 5(1): 49-56.

[FullText](3020) [PDF 364KB](1884)

Abstract:
A diagnostic study is made of a cold wave-related anticyclone in East Asia, for 26—30 January 1980, by using the potential vorticity equations. The results show that at the initiation stage in the vicinity of anticyclonic center there is a low potential vorticity area where it decreases (increases) with the intensification (descension) of the high; when the high developing it descends from the middle troposphere to the nearer ground layer, when the high decaying it ascends from the lower troposphere; while the potential vorticity in upper troposphere increases with the intensification of surface high. The various terms in the potential vorticity equations have made very different contributions to the evolution of the anticyclone. The first contribution comes from the geostrophic advection of potential vorticity and the divergence term of geostrophic deviation wind. The secondary are the advection of geostrophic deviation wind and radiation heating (cooling). The twisting term and thermal wind term could be ignored.

A Relationship Between the Acceleration of Upper Jet and Middle-lower Frontogenetical Function

Li zhenjun

1994, 5(1): 57-61.

[FullText](4429) [PDF 256KB](1569)

Abstract:
Using the data of a cold front event which affected Changjiang–Huaihe area on 27—28 April 1983, the relationship between the acceleration of upper jet stream and middle lower frontogenetical function is discussed. The results explain that in the earlier period of this case, the acceleration is an important contribution to the middle layer frontogenesis but in the latter period baroclinic wave with energy from the basic flow would lead to the lower layer frontogenesis.

The Influence of the Abnormal Snow Cover over the Qinghai-Tibet Plateau on Precipitation

Xu Guochang, Li Shan, Hong Bo

1994, 5(1): 62-67.

[FullText](3143) [PDF 296KB](1810)

Abstract:
According to 1975—1986 satellite snow cover data over the Qinghai-Tibet Plateau provided by NOAA NESDIS, the monthly and seasonal snow cover frequency charts over the Plateau are made. It is found that the Plateau snow cover areas from January to March are widest in a years. And, during the period they appear to be obvious persistence, and there are remarkable relationship between them and Eurasian snow cover areas. In this paper, the influence of abnormal snow cover the Plateau in March upon the circulation and precipitation of China are also examined. It is found that the lag time of direct cooling effect caused by abnormal snow cover over the Plateau is about less than one month. When the snow cover areas over the Plateau in March exceed the normal, north wind over East Asia is strengthened and the precipitation north of the Nanling Mountains, south of China, is less than the normal in the two subsequent months—May.

The Differences of Quasi-stationary Planetary Wave Distribution and Mean Zonal Wind Speed Between Drought and Flood Years in Summer in the Changjiang and Huaihe River Basins

Sun Anjian

1994, 5(1): 68-76.

[FullText](3448) [PDF 412KB](1518)

Abstract:
The differences of quasi-stationary planetary wave distribution and mean zonal wind speed between drought and flood years in summer during 1980’s in the Changjiang and Huaihe River Basins are examined. It is indicated that the central intensity and location of tropical easterly jet are stronger and more southerly in drought years than in flood years. But the latitude location of subtropical westerly jet is more northerly. The summer quasi-stationary planetary wave distributions in drought (flood) years reflect the external source forcing effect by strong (weak) heat source anomaly over around the Philippines and the Tibet Plateau. The differences appear mainly in latitude location relative to large value region of wave amplitude for the mid-high latitudes. The amplitude anomaly distributions of zonal wave numbers of quasi-stationary planetary wave in the E1 Nino events are contrary to those in La Nina events.

The Application of Level-separating Parallel Algorithm to TOVS Data Analysis

Mu Daonan, Wang Zonghao

1994, 5(1): 77-81.

[FullText](3351) [PDF 267KB](1725)

Abstract:
This report discussed how to apply Barnes’ method to the parallel analysis algorithm of 15 level retrieval data from the polar-orbiting satellite NOAA-11 TOVS information, via the level-separating on the IBM4381-P03 with dual CPU at NSMC. The computing results show the speed-up ratio can be reached 3.28.

Acoustic Scattering Attenuation in the Turbulent Atmosphere

Yao Zhanyu

1994, 5(1): 82-89 .

[FullText](3606) [PDF 314KB](1436)

Abstract:
In the paper, an improved formula of atmospheric acoustic scattering cross-section α(θ) is derived and a formula of atmospheric acoustic scattering coefficient αs is established. Moreover, the improved formula of atmospheric acoustic refractive index fluctuation structure coefficient is obtained. The actual measurements show that in the wet air, humidity fluctuation and temperature-humidity cross-correlation fluctuation are the same important factors to atmospheric acoustic scattering attenuation as temperature fluctuation, while in the dry air, humidity fluctuation is ignored.

Numerical Simulation of Volcanic Impact on Climate

Li Xiaodong, Wang Shaowu, Huang Jianping

1994, 5(1): 90-97.

[FullText](2645) [PDF 541KB](1636)

Abstract:
The results of the numerical simulations in Volcano-climate research are synthetically summarized. These simulation results show that the climate change in recent hundred to thousand years is closely related to the volcanism. The large volcano eruption would produce stratospheric warming by 4℃, yearly global-averaged surface cooling by 0.4℃, and monthly about 1℃, respectively. The spatial-temporal characteristics of the temperature drop connect with many factors, such as the eruption features (including latitude location, season, intensity of eruption and so on), the thermodynamic difference between land and sea, the optical properties of the stratospheric aerosols, the change of the meridional latent heat transport caused by the direct radiative forcing, and so on. The research findings concerning Mount Pinatubo eruption in 1991 and its potential climate impact are reviewed.

Characteristics of Solar Spectral Radiation in the Guangzhou District

Xiong Xiaozheng, Wang Xinyu, Wang Gengchen

1994, 5(1): 98-103.

[FullText](3815) [PDF 255KB](2063)

Abstract:
Characteristics of the solar ultraviolet radiation, visible radiation (photosynthetically active radiation) and near infrared radiation are examined by using the data of solar spectral radiations (observed angle is 23°11′) observed in the period of 1985—1990 in the Guangzhou district. The result shows that the monthly amounts of the solar spectral radiations and the total radiation are larger in July—October every year. The monthly mean ratio of visible to total radiation is 47.3%, infrared to total is 45.6% and UV to total is 7.1%. Furthermore, some features of the variations of solar spectral radiations in clear sky and UV radiation in 1990 are also given in the paper. And, the correlations of spectral radiations to cloud amounts, insolation duration and other factors are analyzed and discussed.

Numerical Experiment on Effect of the Blocking High Structure on Unusual Track of Typhoon in Coastal Waters

Xu Xiangde

1994, 5(1): 104-108.

[FullText](3159) [PDF 266KB](1701)

Abstract:
Using numerical experiment method, sensitivity characteristics of the typhoon unusual track to the environment dynamic factors are examined. The numerical simulations show that there significant effect of change of blocking high structure on the northern side of typhoon on unusual phenomenon of typhoon track

A Q-vector Analysis of the Process of Shear Line on Qinghai-Xizang Plateau Triggered form Moving Trough Aloft

Yu Shuhua

1994, 5(1): 109-113.

[FullText](2665) [PDF 218KB](1397)

Abstract:
By using Q-vector analysis of the process of shear line formation over the Qinghai-Xizang Plateau on 1—6 June 1982, which is triggered from a moving trough aloft, it is found that the favorable situations are: (1) the shear line on the Plateau is formed and maintained in a convergent zone extending from east to west at the 500 hPa Q-vector field where ▽? Q＜0, and at 200 hPa ▽? Q＞0; (2) a wide area of ascent current is an important role of formation and maintenance of the shear line; (3) the formation and existance of shear line over the Plateau is connected with frontogenesis to certain extent.

Characteristics of Temperature in Spatial and Temporal Variation in China During Recent 40 Years

Song Lianchun

1994, 5(1): 119-124.

[FullText](5710) [PDF 244KB](1903)

Abstract:
Based on the decadely mean temperature at 336 stations in China from 1951 to 1990, the statistical methods of empirical orthogonal function (EOF) and periodogram are used to analysed the characteristics of temperature in spatial and temporal variation. The facts that the interannual change and change trend of temperature have significant differences among different districts and seasons are revealed. It can be drawn that the temperature decreases in the first 20 years and increases in the last 20 years. And temperature decreases in summer, increases in winter. The periodic oscillation in temperature trend is also analysed in the paper.

The Recognition and Estimation of the Advantages of Artificial Precipitation Enhancement by Neural Network

Wang Lie, Cai Yudong, Yao Linshen

1994, 5(1): 125-128.

[FullText](3160) [PDF 167KB](1498)

Abstract:
The artificial neural network is applied to the recognition of Weather conditions of artificial precipitation enhancement in this paper, and a group of samples is collected as an object of the study. The results show that the performance of the neural network approach is good, and therefore it might be referred as an effective technique for the analysis and recognition of weather conditions of artificial precipitation enhancement.

Vol.5, NO.1, 1994