The Characteristic Analysis Of The MJO In Wintertime And The Influence On Low-Frequency Ozone Distribution Over China

MJO, as an important low-frequency circulation system in the tropical, its activities and its anomalies impact on the composition of the atmosphere cannot be ignored. Paying attention to the relationship between the MJO activity and low-frequency ozone in china is of great significance to understand the intraseasonal oscillation of atmospheric composition, as well as to improve the prediction of the change of atmospheric composition. In this paper, we use the average daily reanalysis data from NCEP/NCAR, NOAA, MACC-Ⅲ, Bureau of Meteorology Research Centre, and a variety of diagnostic analysis methods, such as Butterworth band-pass filter, MV-EOF, EOF orthogonal decomposition, composite analysis, SVD analysis, Liang-Kleeman Information Flow, to discuss the variation characteristics of MJO activity in wintertime and it’s the influence on the low-frequency ozone in China. The conclusions show that:(1) A zonal wavenumber 1 mode with MJO in wintertime, zonal wind field of high and low level configuration is arranged on the contrary, Near equator (15°S～ 15°N) Eastern Indian Ocean-Indonesian Archipelago (Western Pacific), active convection (suppress), and vice versa. The convection activities in the two regions show "anti-phase", so Eastern Indian Ocean-Indonesian Archipelago (60°E～120°E) and west Pacific (120°E～180°E) are selected the key area for winter MJO activity;(2) MJO activity of strong、weak events in the distribution without regularity in the annual winter, but presents certain region, eastern Indian Ocean and the Indonesian archipelago area and the Pacific for the MJO activity often occurs in the region; MJO activity north propagation phenomenon is not obvious, which is mostly east propagation based in winter;(3) The low-frequency ozone characteristics of high winter low summer season distribution, high north low south, east high west low spatial distribution in china;(4) MJO activity of the key area of East Indian and western Pacific has obvious one-way Information Flow to the low-frequency ozone in the southwest, southeast coastal area of china, suggest that MJO has effect on low-frequency ozone, can make the ozone low frequency change, Accordingly the low-frequency ozone Information Flow to MJO is near zero, suggest that low-frequency ozone has no effect on basic MJO activity;(5) MJO active center is located in the key area, our country’s low-frequency ozone negative anomaly distribution, maximum negative anomaly in the east key area, can reach to -4 du/d; Large negative anomaly value center as the MJO active center moved to the east, strength weakened, When MJO active center left key area, the low frequency ozone negative anomaly weakens, even to positive anomalies;(6) East India key area of the low-frequency OLR field is positive (negative)anomaly occur, convection suppress (active), the low frequency ozone of china is positive (negative) anomaly; Key area of the north of western Pacific low-frequency OLR field a negative (positive) anomaly, active convection (suppress), the low frequency ozone of china is negative (positive) anomaly;(7) MJO active in the key areas of the East India, low-frequency circulation field with fairly consistent, active convection, horizontal and vertical motion, accelerated by low frequency to the development of circulation, which changed in China over the low frequency circulation form, and ultimately affect the low-frequency ozone intensity and distribution form of our country. Near the equator low latitude south airflow will be transported ozone to the china, makes china’s low frequency ozone reduction; MJO in the Western Pacific key active zone, anticyclonic circulation control in our country, northerly prevented low latitude ozone transported to middle and high latitudes, also brought in high latitude ozone in the local accumulation, resulting in China’s local low ozone negative anomaly weakened, coupled with two significant cyclonic circulation anomaly with each other, and promote the meridional circulation development, and it has an effect on the low frequency ozone distribution in the coastal area of Southeast China and Huanghuai area.