应用气象学报

2002, 13(4)

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Abstract:

AN ANALYSIS ON DEVELOPMENT OF MESO-Β CONVECTIVE SYSTEM ALONG MEIYU FRONT ASSOCIATED WITH FLOOD IN WUHAN IN 20-21 JULY 1998

Zhang Xiaoling, Tao Shiyan, Zhang Qingyun

2002, 13(4): 377-396.

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Abstract:
On 21 July 1998 a flash flood associated with a meso-β convective system occurred in Wuhan, producing 88 mm rainfall in an hour. A diagnostic study of the genesis and development of the mesoscale convective system (MCS) is presented. The conclusions are as follows: (1) The flash flood occurred during the rapidly developing stage of the MCS. (2) There was aboundent moisture gathered in the lower troposphere and the atmosphere was nearly saturated with a big store of convective available potential energy (CAPE). (3) The MCS became nearly stationary in the vicinity of Wuhan after formed and a great amount of rainfall was accumulated in this area.

SIMULATION OF IMPACTS OF TEMPERATURE ON PHOTOSYNTHETIC PRODUCTIVITY OF SUMMER MAIZE

Liu Jiandong, Zhou Xiuji, Yu Qiang

2002, 13(4): 397-405.

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Abstract:
A combined model is established for simulating photosynthesis of summer maize based on the data observed with Li-6200. Validation of the canopy photosynthesis model by the data observed with GHX-305 CO₂ Analyzer is conducted. The result shows that the mean error of the model is about 6.93%. The impact of temperature on summer maize photosynthetic productivity is derived by the model, which provides the premise for improving numerical models of climatically productive potential of summer maize in the Huanghuaihai Region.

ENVIRONMENT AND CONDITIONS OF MESOSCALE CONVETIVE COMPLEX DEVELOPMENT IN NORTH CHINA PLAIN

Lu Yanbin, Zheng Yongg uang, Li Yaping, Tao Zuyu

2002, 13(4): 406-412.

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Abstract:
The Mesoscale Convective Complex (MCC) can generate the torrential rainfall in the North China Plain. The composite synoptic environment before MCC genesis is obtained based on three typical MCCs selected from the general investigation of MCCs in the North China plain. Through diagnoses and analysis, the conditions of MCC development over North China plain are investigated. The results reveal that the synoptic environment of MCC development in North China plain is neither the same as in South China nor in North American. Since MCCs often occur at night, the results about the environment and conditions for MCC development are helpful in forecasting whether MCC will occur in the early evening of the day over the North China plain.

COMPUTING TEST ON THE REFLECTANCE IN 940 NM WATER VAPOUR CHANNEL

Huang Yibin, Dong Chaohua, Liu Zhiquan, Pan Ning

2002, 13(4): 413-421.

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Abstract:
Based on the interaction between atmosphere and radiance in the near infrared band, conducted is the remote sensing of low-level water vapor, a problem that is hard to solve through the infrared band. The reflectance in 940 nm channel, which is in a weak water vapor absorption spectral band, is calculated, and its sensitivities to various environmental parameters are analyzed. The results show that signals from channels in the 940 nm band carry water vapor information from the whole atmosphere. The water vapor amount can be probably retrieved from it.

APPLICATIONS OF "3S" TO MONITORING OF SOIL MOISTURE CONDITION IN BEIJING

Wang Xiaoyun, Guo Wenli, Xi Wen, Zhang Lianqiang, Zhang Wenzong

2002, 13(4): 422-429.

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Abstract:
Methods for monitoring soil moisture by means of satellite data are discussed. Based on GIS and GPS techniques, the capabilities of analyzing the results of soil moisture conditions through satellite data are improved. Based on the analysis of different models, we developed some models that are applicable in monitoring soil moisture. The combination of geographic data with various data, including information of remote sensing, comes true. Remote sensing technology, in combination with GIS and GPS, improved the resolution of soil moisture monitoring.

CHEMICAL CHARACTERISTICS OF PRECIPITATION IN REGIONAL AIR POLLUTION BACKGROUND STATIONS OF CHINA

Yang Dong zhen, Zhou Huangang, Zhang Zhong hua

2002, 13(4): 430-439.

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Abstract:
Investigation was conducted on the chemical characteristics of precipitation in three WMO regional atmospheric background stations, the representatives of three different background features; Longfengshan (Wuchang County, Heilongjiang Province), Shangdianzi (Gubeikou village, Miyun county, Beijing) and Lin'an (Lin'an County, Zhejiang Province) background stations. The pH value and the contents of ions, SO₄^2-, NO₃^-, Cl^-, F^-, NO₃^-, Cl^-, F^-, NH₄⁺, K⁺, Na⁺, Ca²⁺ and Mg²⁺ in the precipitation were analyzed. The results show that the pH values and concentrations of SO₄^2-, NO^3-, NH₄⁺ and Ca²⁺ have obvious annual and inter-annual variation features. The variation trends are different for the three stations and between various elements. However, the concentrations of ions Cl^-, F^-, K⁺, Na⁺, and Mg²⁺ are quite low, and their variations are negligible. As for the multi-year average, the pH value for Lin'an is the lowest at the three stations, but the SO₄^2- concentration is the highest; while all values at Shangdianzi are the highest, except SO₄^2- concentration is in the middle; and all ion concentrations for Longfengshan are the lowest, except Ca²⁺ and Mg²⁺ concentrations are slightly higher than those for Lin'an, and the pH value is in the middle. The precipitation chemical features of these background stations show that the precipitation is acid at all the three stations. The worst is at Lin'an, better at Longfengshan and the slightest at Shangdianzi. It indicates that the air quality for all these three air pollution background stations is becoming worse.

RELATIONSHIP BETWEEN TROPICAL SST CHANGE AND MONSOON DEVELOPMENT OVER PLATEAU

Ma Zhenfeng, Gao Wenliang

2002, 13(4): 440-446.

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Abstract:
By using NOAA OLR data and NCEP/NCAR reanalysis grid data, the relationship of tropical Pacific and Indian Ocean SST background field changes and the development of monsoon over the Plateau are analyzed. Results show clearly that the SSTA increase on the Bengal gulf, South Sea and West Pacific warm pool in spring is favorable to the development of the summer Plateau monsoon, while the increase in the eastern equatorial Pacific SSTA has the opposite effect. The evolutionary characteristics of the prophase and synchronous SSTA fields, wind fields and OLR fields are also analyzed. Results show that there is great difference in the tropical background field between weak and strong monsoon years over the Plateau. During the development of Plateau monsoon from spring to summer, SSTAs over the Bengal gulf, South Sea and West Pacific are positive, but negative over the eastern equatorial Pacific at the same time, displayed the characteristics of La Nina; and vice versa, displayed the characteristics of El Nino.

INSTABILITY OF EASTWARD MOVEMENT AND DEVELOPMENT OF CONVECTIVE CLOUD CLUSTERS OVER TIBETAN PLATEAU

Zhuo Ga, Xu Xiangde, Chen Lianshou

2002, 13(4): 447-456.

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Abstract:
The eastward movement and development of convective systems over the Tibetan Plateau are investigated with GMS infrared Black-Body Temperature (TBB), T106 reanalysis data and 5 station's sounding data along the Yangtze River basin in 1998. Results show that the processes of heavy rainfall along the Yangtze River basin coincide with the periods of low TBB. The convective cloud clusters display a substantial moving trend from the plateau to the mid and lower reaches of Yangtze River basin. The necessary conditions for heavy rainfall over the Yangtze River basin are the continuous accumulation of clusters at Sichuan and the merging itself with the cloud clusters in the Yangtze River basin and cloud clusters moving from plateau. It is also presented that the vertical structure of circulation, steering effects of high (low) jets, plentiful water over the southeastern plateau and the Yangtze River basin and the instability in troposphere are all favorable to the eastward movement and development of cloud clusters.

DIABATIC ROSSBY WAVES UNDER THERMAL EFFECTS OF TIBETAN PLATEAU

Li Liming, Bai Jingyu, Huang Feng, Liu Shikuo, Wang Zhang gui

2002, 13(4): 457-468.

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Abstract:
From diabatic quasi-geostrophic equations of motion, the characteristics of diabatic Rossby waves under the thermal effects of the Tibetan Plateau are analyzed. When the basic zonal flow is barotropic, it is demonstrated that the cooling of the Tibetan Plateau in winter not only facilitates the meridional propagation of Rossby waves, but also is an important driving mechanism of the intraseasonal oscillations in the middle and high latitudes. The large-scale heating of the Tibetan Plateau in summer prevents Rossby waves from propagating meridionally. When the basin zonal flow is baroclinic, it is found that the cooling of the Tibetan Plateau in winter facilitates the instability of Rossby waves, while there is a threshold in the influence of the heating of the Tibetan Plateau in summer on the stability of Rossby waves.

STATISTICAL FEATURES OF THE ULTRA-SHORT-RANGE PRECIPITATION DURING EARLY RAINY SEASON IN FUJIAN PROVINCE

Lin Xinbin, Liu Zengji, Zou Yan, Ren Hanlong, Zhou Rongzhen

2002, 13(4): 469-477.

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Abstract:
The climatic frequency and probability of the ultra-short-range rainfall during the early rainy season (in May and June) over Fujian Province are classified and compared. Results show that the rainfall features are different in regions with different topographical features, including the height above the sea, the distance to the sea, the direction of the mountains, hills, valleys, etc. Results reveal that the topographical differences play an important role in rainfall in Fujian Province.

A PRELIMINARY RESEARCH ON RELATIONSHIP BETWEEN PRECIPITATION IN SPRING IN XINJIANG AND SSTA IN NORTHERN ATLANTIC

Yang Duo, Shi Yuguang

2002, 13(4): 478-484.

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Abstract:
The lag and contemporary correlation coefficients are calculated between precipitation in spring in the northern Xinjiang, the southern Xinjiang and the Tianshan Mountain area and SSTA in the Northern Atlantic Ocean. It is found that the relationship between precipitation anomaly in spring in Xingjiang and SSTA in the preceding July in Northern Atlantic Ocean is the best, generally. The SVD method is used to identify corresponding distribution patterns between precipitation fields and SSTA fields, which are verified by real data, finally.

RELIABILITY STUDY OF DETERMINING WIND WITH DUAL-DOPPLER RADARS

Zhang Peiyuan, Zhou Haiguang, Hu Shaoping

2002, 13(4): 485-496.

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Abstract:
Based on the theories for determining wind fields with dual-Doppler radars and the technology of Doppler radar data processing, the intrinsic factors affecting dual-Doppler retrieval reliability are analyzed. Because of the limitations of radar determination methods, there exist non-simultaneity and differences in illuminant volumes and spatial positions in measurement data from two radars. Since the microwave transmission curve is not straight and the earth surface is not flat, the retrieval of the dual-Doppler radar sounding technology is influenced seriously. When wind fields derived from dual-Doppler radar observation are used, their reliability must been analyzed.

A BRIEF REVIEWON THE DEVELOPMENT OF ENSEMBLE PREDICTION SYSTEM

Chen Jing, Chen Dehui, Yan Hong

2002, 13(4): 497-507.

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Abstract:
The main issues of the Ensemble Prediction System (EPS) are presented, such as ensemble prediction concepts, the structure of an EPS, approaches for generating initial perturbation, interpretation and application schemes of EPS outputs. The recent advancements and progresses of the operational implementation and research results of EPS are systematically summarized, as well as the projects of EPS development in the developed countries.

CONVERSION COEFFICIENT OF SMALL EVAPORATION PAN INTO E-601B PAN IN CHINA

Ren Zhihua, Li Mingqin, Zhang Weimin

2002, 13(4): 508-512.

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Abstract:
In order to connect evaporation data observed from 20 cm diameter evaporation pans in the past 40 years with those from E-601B pans, a comparison of evaporation data is made between 20 cm diameter pan and E-601B pan from 618 evaporation experimental stations for three years. The monthly and annual-mean conversion coefficients for the two instruments and the nationwide distribution chart of the annual-mean coefficient, as well as the corresponding standard deviation and relative standard deviation, are given.

Vol.13, NO.4, 2002