应用气象学报

Experiments on the Medium-range Numerical Weather Prediction

1987, 2(2): 113-122.

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Abstract:
The initialization scheme of nonlinear balance equation is a more useful method not only in the balance model but also in the primitive equation model. But as we know that the routine method for solving the nonlinear balance equation contains the exaction of the square root, this operation consists of many operations of arithmetic in computing. Especially this calculation is to be performed at every gridpoint in every step of iteration, and to be required more iteration times. So the amounts of computations are considerably large. In this paper, a new and very efficient method for solving the nonlinear balance equation is proposed, and the difficulties mentioned above have been already removed. The experiments on medium-range numerical weather prediction are performed by using the seven-level spectral model with different initialization schemes including the nonlinear balance equation, linear balance equation, “nongeostrophic stream function”, and simply geostrophic wind. From the results, we can see that the nonlinear balance equation initialization scheme is the best one. Because of the absence of nonlinear terms in the linear balance equation initialization scheme, the forecasting results of weather system are rather smooth and weak

A Numerical Experiment of the Effect of Large Scale Heating of Condensation

1987, 2(2): 123-132.

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Abstract:
In this paper, the large scale heating of condensation is added into the adiabatic scheme of the five level primitive equation model. The 48-hour forecast for the cyclone development over the Yellow River has been obtained. By contrast with the prognostic charts of the adiabatic scheme, it is quite evident that the large scale heating of condensation reinforces the intensity of the cyclone and improves the prediction.The conditions of the condensation are revised by considering the experience of synoptic meteorologists. We have tried a few cases and obtained eventually a satisfactory result.

Numerical Simulation of Microphysical Processes of Stratiform Clouds (II)—Microphysical Processes in Middle-latitude Cyclone Cloud Systems

1987, 2(2): 133-142.

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Abstract:
Our cloud model (Paper I) was run to calculate the microphysical structures of clouds and pricipitation associated with middle latitude cyclones, by using the observed temperature and updaft as input. The results agree with observations in many aspects. The “seeder-feeder” mechanism, seeding by generating cells and warm rain process in shallow stratiform clouds have been demonstrated. The two-parameter model and the equations of ice nucleation, cloud-rain autoconversion and ice multiplication seem to be reasonable, but the equation of ice aggregation is not good enough

A Case Study on Microphysical Characteristics of Precipitation Particals Near the Melting Layer

1987, 2(2): 143-150.

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Abstract:
The process of snow melting and the size distribution function of hydrometeors near the melting layer are described. The size distribution of snow, collapsed snow and raindrop can be fitted in with the expression of N=N0exp(-λD) near the melting layer, the spectral parameters N0 and λ are related to temperature, the relation between N0 and λ, can be fitted in with the expression of N0 =σλβ, parameter β is determined by hydrometeors

The Evolutioin of Double-ring Cloud Wall of Concentric Eye Typhoons

1987, 2(2): 151-157.

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Abstract:
By using aircraft sounding data (1949—1985) of 83 typhoons, the evolution of the double-ring cloud wall of concentric eye typhoons are analysed. It is found that there are three types of evolution: ① In the first type, accompanying the increase of typhoon intensity with time, the diameter of cloud wall encircled the original eye region of typhoon gradually shrinks. Meanwhile, a new cloud wall occur in the periphery of the region and then invade inward. So a double-ring cloud wall is formed. Then the inner wall rapidly disappears and the outer wall gradually shrinks. Usually, several processes similar to the above evolution may occur successively and the intensity of typhoon would oscillate with time. ② In the second type, a closed cloud wall occurs and invades from the periphery of the typhoon eye region. The evolution of the outer cloud wall is quite complex. It may sometimes shrink, and sometimes extend. In some cases the double-ring cloud wall lasts for a period of time, and in other cases its outer wall disappears rapidly. ③ In the third type, the double-ring cloud wall is formed as a result of the development of cumulus convection inner region of typhoon into a well-closed inner cloud wall. The inner wall usually lasts for a period of time and then rapidly disappears.

The Atmospheric Heat Source over Qinghai-Xizang Plateau During the Summer 1979

1987, 2(2): 158-165.

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Abstract:
In this paper, by using data for 17 stations on Qinghai-Xizang Plateau during the period of June—August 1979, the components of the heat source, including long-wave radiation, short-wave radiation, latent heat, and flux of sensible heat are calculated. Based on these results the average atmospheric heat budget over Plateau is calculated. Having compared our results with those given by authors in China and in foreign countries who use the indirect method for calculation, the main contribution to the atmospheric heat source in our calculation is the long-wave radiation. Also, the relationships between the atmospheric heating field over Plateau and the monsoon circulation in various stages over Plateau are discussed.

The Characteristics of Zonal Winds at 500 hPa in Eurasian Region and Its Relation to the Weather in China

1987, 2(2): 166-173.

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Abstract:
In this paper, two indices have been defined. One is the circumpolar area index of north to the westerlies and the other is the intensity index of westerlies. It has been found that by using these two indices the zonal circulation in the Northern Hemisphere has several periodical oscillations and that the weather in China is closely related to the intensity and the northward or southward shift of the westerlies in the Northern Hemisphere.

Assessment of the Effectiveness of Regression Equatioin

1987, 2(2): 174-181.

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Abstract:
Based on the sum of regression residual square (Q) and the criteria for choosing some of undependent variables, a choice criterion for improving the forecast accuracy is discussed. Also, the effectiveness of these criteria is examined and compared on the basis of skill scores in the forecast experiments

Relationships Between Water Consumption for Wheat Field and Winter Wheat Growth

1987, 2(2): 182-188.

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Abstract:
According to the experimental data of controlling water for winter wheat field in Taian, Shandong Province during 1983—1984 and 1984—1985, the relationships between the water consumption for wheat field and winter wheat growth, physiological condition and yield of winter wheat have been analysed. Optimum water index and optimum yield from the jointing stage to mature stage have been obtained. In this paper, We have also discussed water usage effect.

A Study on the Comparison of Several Kinds of Network Evaporimeters

1987, 2(2): 189-196.

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Abstract:
Some types of network evaporimeters were compared with standard evaporimeter in Guangzhou, Yingpan evaporation experiment stations and Beijing Meteorological Observatory during 1981—1985. In this paper, the performance of these kinds of evaporimeters has been analyzed by using the experimental data. Some interesting results are presented.

A Statistical Analysis on the Extratropical Cyclones in the Eastern Asia and North America

1987, 2(2): 215-219.

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Abstract:
By using weather maps for ten years (1964—1974), a statistical analysis on the extratropical cyclones in the eastern Asia and North America are made. It is found that the geographical distribution of cyclonic activity, their seasonal distributions have marked several differences between these two regions and that the effect of monsoon and orientation of Tibetan Plateau play an important role for the difference of cyclonic activities in these two regions

A Study on the Relationship Between the Masses and Dimensions of Snow Crystals

1987, 2(2): 197-201.

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Abstract:
The linear dimensions of snow crystals and melting drops of the same crystals on the rabbit fur were observed in Wulumuqi in the wintertime of 1984. The relationships between the masses and dimensions of the side plane, rosette, plane dendrite and spatial dendrite crystals have been obtained.

The Climate Oscillation of Summer Temperature in Northeast China and Its Characteristics of Atmospheric Circulation

1987, 2(2): 202-208.

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Abstract:
In this paper, the oscillation of summer temperature in Northeast China and its characteristics of atmospheric circulation during 1910—1980 are discussed. The relationships between the summer temperature in Northeast China and the sea surface temperature in the equatorial eastern Pacific are also analyzed. The study results obtained show that: ① The change of summer temperature can be divided into three cold and two warm periods. The characteristics of atmospheric circulation in the cold periods are quite different from that in the warm periods. ②There is a good negativecor relation between the summer temperature in Northeast China and the sea surface temperature the equatorial eastern Pacific

Seasonal Variation of Atmospheric Circulation and the Rainy Years

1987, 2(2): 209-214.

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Abstract:
Based on the observed wind data during 1971—1980, the seasonal variations of the meridional and zonal wind fields in 140oE section are analysed. It is found that in rainy tears during June-July the summer season in the Southern Hemisphere ends 1—2 months earlier than normal in the middle and lower Yangtze River, while the summer season in the Northern Hemisphere starts 1—2 months later than normal. It shows that the flood in the Mei-yu period seems to be associated with the anomalies of the circulations in the Southern and Northern Hemispheres

A Method for Medium-range Forecasting of Heavy Rain in Mei-yu Period

1987, 2(2): 220-224.

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Abstract:
The method of multiplayer recursion is a new numerical forecast method using the theoretics of system identification in modern cybernetics. The harmonic analysis can reveal the characteristics of wave motion in various scales at different latitudes. In this paper, we have used the combination method to forecast medium-range heavy rain in Mei-yu period. The results show that the multiplayer recursion forecast model with increasing memory in the best one.

1987, 2(2)

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Abstract:

Vol.2, NO.2, 1987