Abstract:The study on the climate predictability is a very important aspect of the climate change research. Firstly, the two key reasons for which the short term climate prediction is feasible, as well as the substance of the short term climate predictability are introduced. Secondly, the Analysis of Variance (ANOVA) technique, which is used to study the monthly or seasonal predictability, including the predictability of both the real atmosphere and the model atmosphere are explained. Finally, the research conclusions about short term climate predictability at present are reviewed.

Abstract:Based on the Mesoscale Eta coordinate Model (MEM), which contains 16 levels in the vertical with different intervals, a high resolution PBL scheme with 21 levels is introducted. Using the improved model, the numerical simulations of heavy rain case are done. The results show that the improved model has a great progress in the heavy rain forecast, the TS score for the precipitation, especially, for the heavy rain, is obviously higher than the former model. This is very important in the model′s operational use in the near future. The sensitivity test shows that it is useful for the heavy rain forecast with increasing the model′s vertical resolution. Additionally, the model is sensitive with the mixing length and the moist available quotiety, and influence of the features of model underlying on the prediction results is important.

Abstract:In order to strengthen the ability to monitor Guangdong meso scale weather phenomena, a meso scale monitoring and predicting system as well as more than 600 AWSs was built in Guangdong Province. How to improve its regular organization efficiency and fully develop its effectiveness, the main issues are to construct and to use the databases very well. The main idea to do this is, based on the CMA′s "9210" program meteorological database, to extend mesoscale AWS′s database, to solve the problem of the relationships between the databases, and to set up a batch of meteorological application systems.

Abstract:A number of special type data, which reflect the property of the life and various trades involving with the meteorological conditions and sensitivity, are collected and sorted out. Combined with many kinds of meteorological factors, the environmental and meteorological indexes with linear/nonlinear methods are built. Using the numerical weather forecast products, a operational system of environmental and meteorological index series is set up.

Abstract:Based on the late rice yields and climate data ,the indexes of the rice yield and their climate parameters in the main growing area are analysed.Then, based on the analysis of the characteristics of the late rice climatic year′s harvest in different provinces, a regression model to evaluate the climate potential is set up, and the model was used in the operational agrometeorological yield forecast in 2001. The results are very satisfactory.

Abstract:Based on the experiments, a new field calibrating method with a neutron moisture meter is developed, including installed only once, no irrigation, data filtration of scatter diagram, three dot smoothing method for the volumn water content rate, volumn weighted smoothing method and so on. The methods are simple, utility and easy to being operated. The calibrating equation has high accuracy.

Abstract:The cause of the heavy rainfall occurred in central Yunnan Province from June 30,2002 is analysed with the MICAPS data, GMS satellite images and the echo data of Doppler Weather Radar 3830 C.It is found that this heavy rainfall process is caused by cold vortex and mid low level shear. The heavy rainfall region is corresponding with the strong ascending region of vertical speed and vorticity, and accompanied with the high energy and high wet regions. There is a developing mesoscale cold vortex cloud cluster from the satellite image. Furthermore, the radar echoes show that some obvious mesoscale systems (for example: mesoscale convergence line, mesoscale cyclone, anti wind area, etc.) with typical convective characteristics occurred during this heavy rainfall process.

Abstract:The longest, continuous autumn rain events occurred in the central and eastern part of northwest China in 2000 and 2001 (Sep. to Oct.) since the mid 1980s. The impact of general circulation and sea surface temperature, especially the west Pacific subtropical high and sea surface temperature on the continuous autumn rainfall is analyzed. And the patterns of 5 day mean circulation of continuous autumn rainfall over 500hPa geopotential height field in Europe and Asia regions are given.

Abstract:Based on the winter temperature data of Zhejiang Province since 1954, the warm winter years of Zhejiang Province are defined. It is found that in the warm winter the zonal circulation in the westerly belt of Asia is always popular and the intensity of west Pacific subtropical high is stronger than the mean and its position is westward of the mean. So, the warm winter years have a good relation with the total precipitation of Zhejiang Province during the flood season and the number of typhoon effecting Zhejiang Province during the typhoon season.

Abstract:By analyzing the change of moist potential vorticity (mpv) field and baroclinicity, a heavy rain event occurred in the northeast Huaihe basin from 30 to 31 August 2000 is discussed. It is found that this heavy rain is closely related to the typhoon disturbance which triggered off the evolution of circulation field. Furthermore, the key of the heavy rainfall is interaction between the typhoon warm and wet weather system and the cold convergence system.

Abstract:A process of heavy rainfall at Datong City from August 18 to 19, 2001 is analyzed. It is shown that the event is caused by the interaction among the upper westerly trough, the subtropical high and the lower shear, especially, the critical systems such as the Hetao depression and vapor convergence zone are analyzed in detail. It will be as a reference of heavy rainfall forecast.

Abstract:Based on the data at Shapingba, Chongqing city from 1951 to 2001,an analysis of the primary characteristic variables of fog and correlative meteorological factors in Chongqing city are made.So it shows that urban heat island effect resulted in the Foggy City′s fogdays.

Abstract:The differences due to the different descriptions of visibility terms described by various countries and international organizations are introduced, especially, the difference between meteorological visibility, visibility demanded by aviation and runway visual range. This work will benefit aviation circles to understand the use of visibility and it is of importance for us how to contact with international standards after jointed WTO.