Vol.4, NO.4, 1993

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A Numerical Experiment of the Influence of Underlying Surface on a Short-range Synoptic Process (II)
Du Huawu
1993, 4(4): 385-393.
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Abstract:
The effect of variation in characteristics of underlying surface for a local region on the short-range precipitation and circulation over the region and its vicinity has been studied by using the same case and model as used in the paper. Furthermore, its possible mechanism and the differences between the effect of variation in characteristics of underlying surface for a local region and that for a wide region are discussed, respectively.
Effects of Ambient Wind on the Development of Orographic-convective Cloud
Gu Guojun Wang Angsheng
1993, 4(4): 394-401.
[FullText](3356) [PDF 379KB](1763)
Abstract:
The paper simulates the effects of ambient wind on the development of orgraphic-convective cloud by means of a two-dimensional compressible convective cloud model with terrain-following coordinate. The results indicate: Ambient wind has a great influence on the developing intensity, structure and precipitation of orographic-convective cloud over an upslope. When the middle-upper wind and lower upslope wind are in the reverse direction, the large the wind speed and Shear intensity of middle-upper level wind, the severer the convection; when in the identical direction, ambient wind will weaken the maximum intensity of convection.
The Low Frequency Oscillation Characteristics of Typical Drought/Flood in the Low and Middle Reaches of Huanghe River
He Sulan Song Lianchun
1993, 4(4): 402-407.
[FullText](3808) [PDF 300KB](1316)
Abstract:
The methods of band-pass filter and power spectrum are used to analyse atmospheric low frequency oscillation (LFO) (30—60 days) characteristics of 500hPa geopotential height field over the Northern Hemisphere in typical drought/flood year in the low and middle reaches of Huanghe River. The facts can be drawn as follows: The characteristics of LFO in summer drought appear that longer period and higher spectrum value occurred in Bejkal Lake region and shorter period and lower spectrum value in Ural, while the characteristics of LFO in flood year in Ural, Bajkal lake and subtropical regions are contrary to those in drought year
An Analysis of Atmospheric Stratification Factors Before Severe Convective Precipitation
Zhong Xiaoping
1993, 4(4): 408-414.
[FullText](2892) [PDF 327KB](1479)
Abstract:
After analysing of cases wind and without severe convective precipitation, fourteen factors, which have special indication in a short time before precipitation, have been screened out by using the significance test method from sounding data at a single station. More remarkable instructive seven factors denoting the convective instability, conditional instability, contents of moisture, and homogeneity of atmosphere vertical stratification for torrential rains are given. These factors can apply to the short-range forecast for the severe precipitation
A Method for Determining the Sensor Degradation Rates of NOAA AVHRR Channels 1 and 2
Wu Aisheng Zhong Qiang
1993, 4(4): 514-420.
[FullText](3023) [PDF 297KB](1613)
Abstract:
A method is described to determine the degradation rates of NOAA AVHRR visible channels. 38 desert targets (each 20 km×20 km ) were selected over the northwest of China after testing uniformity of the underlying surface. Two cloudfree data sets for the same satellite were sampled from two different periods several years apart. The functional relationships were established between the observed reflectances and the satellite observation angles. By allowing comparison of the functional relationships of the two different periods and computation of the sensor degradation rates using the stepwise regression method, the degradation rates were detemined to be 5.8% and 4.6% per year for channels 1 and 2, respectively, based on the NOAA-9 AVHRR data for October 1985 and September 1988.
Mean Cloud Image Features of Severe Storm Rainfall of the Changjiang—Huaihe Rivers in 1991
Xu Jianmin Ji Liangda Wang Feng Huang Tao Cui Xiaoping
1993, 4(4): 421-425.
[FullText](3413) [PDF 268KB](1195)
Abstract:
This paper mainly uses mean cloud image data to investigate the spatial distribution features of the large scale cloud band of the Changjiang-Huaihe Valley severe storm rainfall in the flood perion of 1991. The analysis shows that there are three cloud bands extending to Changjiang-Huaihe River areas. Two major water vapor paths are from South China Sea and the Bay of Bengal, respectively. They show the transportation function of water vapor from the low latitude to the middle latitude. Besides, this paper also analyses the effect of the Tibetan high on the Changjiang-Huaihe Valley storm rainfall.
Climatic Characteristics of Explosive Cyclone over the North Pacific Ocean
Qi Guiying
1993, 4(4): 426-433.
[FullText](3370) [PDF 412KB](1565)
Abstract:
Using 1968—1987 synoptic charts, the climatic characteristics of extratropical cyclones over the North Pacific Ocean have been analysed. This paper gives some results of the study of cyclone’s genetic frequency, wind intensity and its quadrantal distribution. The changes of strong wind, central pressure as well as the rate of deepening of cyclones are also estimated
The Relationship Between Principal Components of Geopotential Height and Barotropic Energy Conversion in Winter
Wang Guomin
1993, 4(4): 434-439.
[FullText](3416) [PDF 299KB](1642)
Abstract:
An empirical orthogonal function analysis is performed by using the observed 500hPa monthly mean geopotential height field in the northern winter for 34 years, and then a statistical analysis is made for the relationship between the first five principal components and the barotropic energy conversion process. The results show that it is helpful to the generation and maintenance of low-frequency circulation anomalies throughout the barotropic energy transfer from basic flow-frequency disturbances.
Effects of Thawing Rate on Frost Injury of Crops
He Weixun Feng Yuxiang Xia Manqiang
1993, 4(4): 440-445.
[FullText](3873) [PDF 312KB](1578)
Abstract:
The frost injury is studied by means of the artificial frost-box with the temperature of -1—1℃. The slow radiative cooling process in the frost night are simulated with the thawing rates of 0.3℃/10min and 1.6℃/10min, respectively. It was shown that the severity of frost injury is affected by variety of crop, freezing temperature, freezing process and thawing rate. Under some conditions the frozen tissue may be recovered by means of slow thaw, but, under otherwise conditions it may not. For the varieties of crops with different frost tolerance, the focus of attention to prevention of frost damage should be distinct.
A Study on the Simulation Model of Rice Growth
Li Chunqiang Wang Futang
1993, 4(4): 446-452.
[FullText](3703) [PDF 295KB](1708)
Abstract:
A simulation model of late-sown rice growth and yield formation was built by using the field experimental data in 1989 and 1990. In this model, the biological processes such as photosynthesis, respiration and growth are considered. Photosynthesis is affected by radiation, temperature and leaf area index. Respiration includes growth respiration and maintenance respiration, as well as photo-respiration. Growth is modeled using net assimilation partition, and yield formation using net assimilation accumulation. The result shows that the simulation model gives a good agreement with the observations from field test
Lyapunov Esponent Model for Forecast
Lin Zhenshan Nan Fang
1993, 4(4): 453-457.
[FullText](3916) [PDF 217KB](1653)
Abstract:
Considering the systemic exponential divergent behaviour appearing nearby the attractor, the theory about chaos is combined with statistics, and then the Lyapunov exponent forecasting model is presented in the paper. The results of case tests show that the practical model is satisfactory.
Signal Detection of Volcanic Impact on Climate
Li Xiaodong Wang Shaowu Huang Jianping
1993, 4(4): 458-467.
[FullText](3187) [PDF 582KB](2401)
Abstract:
The representative studies on the volcano impact on climate and their progress are reviewied systematically from two aspects: Superposed-Epoch analyses and Time-series analyses. The temporal and spatial characteristics of the climate response connected with the eruption intensity, eruption latitude, eruption season and other eruption features are shown. Some other questions related to the volcanic signal detection, such as, the volcanic index, the possible mechanism by which the volcano affects the climate, the connection between the volcano and ENSO, and so on are discussed. Finally, the research prospects in the near future are envisioned.
Advances on the Simulation of Human Activity Effects Upon Climate Change
Zhao Zongci
1993, 4(4): 468-475.
[FullText](3314) [PDF 493KB](1526)
Abstract:
The recent advances on the numerical simulation of human activity effects upon the global climate change have been presented in the paper.
Measurement of the Atmospheric CO2 Concentration with the Nondispersive Infrared Gases Analyzer
Wen Yupu Xu Xiaobin Shao Zhiqing
1993, 4(4): 476-480.
[FullText](3332) [PDF 220KB](1969)
Abstract:
The technique for high precision measurement of atmospheric CO2 has been developed by improving of the import nondispersive infrared CO2 analyzer. The system precision with better than 0.1ppm is attained and possessed the better comparability. It meets the requirements of the Global Atmosphere Watch of WMO. On the basis of measurements in situ, the data of background CO2 concentrations over the continent of China are first obtained
Influence of Cold Surges and Its Feedback in Northern Winter on Precipitation in the South of China
Zhang Yuanzhen Wu Hong Zhang Xingwang
1993, 4(4): 481-486.
[FullText](3480) [PDF 306KB](1348)
Abstract:
The interactions between middle and low latitude synoptic system in the winter season of the Northern Hemisphere and their relationship with precipitation in the south of China have been comprehensively studied. The results show that when precipitation occurs, the polar-front jet is merged with subtropical jet, and then intensified, meanwhile, the jet entrane appears supergeostrophic wind. This phenomenon sometimes is connected with the increase of Hadley circulation and the convection caused by cold surges of the Northern Hemisphere arriving middle and low latitude, and with its feedback. It offers favorable conditions for precipitation in the south of China.
The Climatic Characteristics of the Coldest Date and Their Average Temperatures in China
Chen Shaoqing Chen Mou Feng Zhongyan
1993, 4(4): 487-491.
[FullText](3096) [PDF 272KB](1523)
Abstract:
By means of the five day overlapping average, the geographic distributions of the occurrence of the coldest data and daily mean temperature in China are analyzed in the paper. It is found that the distributions are mainly characterized by the zonal pattern. It is also found that the coldest date occurs in the third nine—day period after the winter solstice in most areas of China except Northwest China, the north of Northeast China and the south of Yunnan Province, and the coldest daily mean temperature is lower and lower rapidly from south to north
The Vertical Structure of Atmosphere and Its Teleconnection
Yang Chengbin Wang Meihua Peng Ru
1993, 4(4): 492-497.
[FullText](2809) [PDF 298KB](1463)
Abstract:
The relationship between the vertical structure and the teleconnection patterns is studied by using the 500hPa height data ranging to the north 20°N and to the south of 20°S spherical regions. The results show that the atmospheric equivalent barotropic structure is in connection with the wavetrain-type teleconnection patterns, and the baroclinic structure is in relation to the zonal-type teleconnection patterns
Application of Pressure-energy Field to Heavy Rain Analysis
Chen Zhongming
1993, 4(4): 498-503.
[FullText](2609) [PDF 315KB](1381)
Abstract:
Using pressure-energy technique, some cases of heavy rain in Changjiang-Huaihe river valley are investigated. It is found that the rain belts and heavy rain area are related to the dense pressure-energy belt. The triggering effect of pressure-energy on heavy rain is studied by using simplified divergence equation. The results show that inhomogeneity of pressure-energy distribution can trigger the quick reinforcement of convergence in the low energy side of the belt. Furthermore, the rain area can be estimated by computing the pressure-energy distribution.
Integration of Non-rectangular Hyperbolic Photosynthetic Model and Sensitive Analysis
Wu Yuanzhong Duan Xiangsuo Li Linying
1993, 4(4): 504-508.
[FullText](4010) [PDF 188KB](1325)
Abstract:
Because of non-rectangular hyperbolic photosynthetic model being more active response to photosynthesis, its integration for the single leaf area is performed in the paper. And, the model is applied to the calculation of the dry matter weight in the paddy fields. The accuracy of calculation is higher than that of the integration formula with rectangular hyperbolic photosynthetic model. The experiment of the parameter sensitivity is conducted. Furthermore, some problems of the seed breeding and numerical simulation are indicated
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