Peng Y.-P.,Nanjing University of Information Science and Technology |
Peng Y.-P.,Chinese Academy of Meteorological Sciences |
He J.-H.,Nanjing University of Information Science and Technology |
Chen L.-X.,Chinese Academy of Meteorological Sciences |
Zhang B.,China Meteorological Center
Journal of Tropical Meteorology | Year: 2014
There has been a lot of discussion about the atmospheric heat source over the Tibetan Plateau (TP) and the low-frequency oscillation of atmospheric circulation. However, the research on low-frequency oscillation of heat source over TP and its impact on atmospheric circulation are not fully carried out. By using the vertically integrated apparent heat source which is calculated by the derivation method, main oscillation periods and propagation features of the summer apparent heat source over the eastern TP (Q1ETP) are diagnosed and analyzed from 1981 to 2000. The results are as follows: (1) Summer Q1ETP has two significant oscillation periods: one is 10-20d (BWO, Quasi-Biweekly Oscillation) and the other is 30-60d (LFO, Low-frequency Oscillation). (2) A significant correlation is found between Q1ETP and rainfall over the eastern TP in 1985 and 1992, showing that the low-frequency oscillation of heat source is likely to be stimulated by oscillation of latent heat. (3) The oscillation of heat source on the plateau mainly generates locally but sometimes originates from elsewhere. The BWO of Q1ETP mainly exhibits stationary wave, sometimes moves out (mainly eastward), and has a close relationship with the BWO from the Bay of Bengal. Showing the same characteristics as BWO, the LFO mainly shows local oscillation, occasionally propagates (mainly westward), and connects with the LFO from East China. In summary, more attention should be paid to the study on BWO of Q1ETP.
Ge F.,Nanjing University of Information Science and Technology |
Babar Z.A.,Nanjing University of Information Science and Technology |
Guo S.-L.,Nanjing University of Information Science and Technology |
Zhi X.-F.,Nanjing University of Information Science and Technology |
And 2 more authors.
Mausam | Year: 2014
Extreme weather events over Asia particularly in Pakistan are becoming more frequent in the present decade or so. This is contributing to the ever increasing human suffering of the region. In this study the whole energy parameter E from atmospheric energetic theory is derived. The characteristics of atmospheric energy conversion during the heavy rainfall in Pakistan for the period 27-29 July, 2010 are also discussed. The results show that due to the impact of the atmospheric circulation and terrain conditions, the kinetic energy is converted into potential energy, in the form of standing wave, during heavy rainfall development period. The conversion between kinetic and potential energy is significant in heavy rainfall spell. High energy value corresponds to the heavy rainfall region.
Xiao T.,Chengdu University of Information Technology |
Jin R.,China Meteorological Center |
Wang M.,Wuhan Institute of Heavy Rain |
Jia L.,Wuhan Institute of Heavy Rain
2010 International Conference on Mechanic Automation and Control Engineering, MACE2010 | Year: 2010
The wave packet perturbation energy propagation and accumulation signal during continuing heavy rain process in west of Sichuan Basin from September 22, 2008 to September 27, 2008 is analyzed and predicted in wave-packet propagation diagnosis method by making use of NCEP/NCAR reanalysis materials. According to the analysis, the distribution and propagation of wave packet can obviously reflect features of generation, lasting and ending of the rain. The high value area of the wave packet is basically consistent with heavy rain areas. The heavy rain process is generally generated in high value period or high phase of the wave packet perturbation energy accumulation. According to the meridional and zonal propagation features of the wave packet value, the continuing heavy rain process in west of Sichuan Basin from September 22, 2008 to September 27, 2008 was mainly affected by West Pacific subtropical high, cold air in northern regions and plateau regions, two water vapor channels from Bay of Bengal and South Sea to the basin as well as Typhoon Hagupit. The evolution of wave packet is meaningful for prediction. ©2010 IEEE.
Xiao T.,Chengdu University of Information Technology |
Ge F.,Chengdu University of Information Technology |
Chen Y.,China Meteorological Center
Proceedings - 2010 7th International Conference on Fuzzy Systems and Knowledge Discovery, FSKD 2010 | Year: 2010
Based on NCEP/NCAR reanalysis grid materials, wave-packet propagation diagnosis (WPD) method and wave-packet distribution features of the "7.17" heavy rain in Chongqing in 2007, the paper made research into the relationship between the energy propagation, accumulation and dispersion features and the rain process. The result shows that: (1) before regional heavy rain, the perturbation energy of the whole atmosphere is enhanced and is spread from higher layer to middle layer with generation of rain and the perturbation strength is reduced. Before basic end of rain, the atmosphere perturbation energy is reduced suddenly. It can be seen that the generation and end of rain is related with enhancement and reduction of perturbation energy. (2) as for this example, the perturbation energy changes most obviously at 600hPa∼400hPa and the perturbation energy in the middle layer is always the strongest center of the whole atmosphere. The average perturbation energy of main rain region at 500hPa is enhanced before rain due to impact of propagation of perturbation energy in other regions and maintains in relatively strong phase and is obviously reduced before end of rain. (3) The wave-packet value distribution and propagation at 500hPa shows that the perturbation energy with impact on heavy rain in Chongqing mainly comes from high-latitude areas, Bay of Bengal region, plateau areas and eastern coastal areas. Propagation and accumulation of perturbation energy in Bay of Bengal region and plateau areas is very obvious before and during the rain while propagation and accumulation in southeast coastal areas and West Pacific areas is not completely simultaneous with that in other areas but is also a key link with impact on accumulation of perturbation energy in rain regions. The heavy rain center is basically corresponding to the strong perturbation energy area and the heavy rain always happens after accumulation of strong perturbation energy to a certain extent, which shows that propagation and accumulation diagnosed in wave-packet propagation diagnosis method is meaningful for predication, analysis and instruction of regional rain process. ©2010 IEEE.