The Characteristic Of The Spatial And Temporal Distribution Of MJO And Its Relationship With Ozone Distribution In The Pacific Ocean

Based on the daily outgoing long-wave radiation(OLR)data of NOAA from 1979 to 2013,the daily reanalysis data of ECMWF from 1979 to 2015,and the global real-time multivariate MJO index(RMM index)of the Australia Meteorological Research Center,this paper analyzes the characteristics of both the spatial and temporal distribution of MJO and the low-frequency ozone of the Pacific Ocean by the statistical methods.Besides,in order to find out the general relationships between MJO activities and low-frequency ozone,this article work on their correlation distributions.The main conclusions are as follows:(1)The OLR data in different seasons are analysised by using the empirical orthogonal function(EOF)analysis,it is shown that the activity of MJO has a seasonal and regional variation.It is usually found in the bay of Bengal region,the Indonesian islands,and the equatorial eastern and western Pacific Ocean.MJO can be divided into two types base on the characteristics of different seasons.It is found that eastward propagation characteristics in spring and winter,and in summer and autumn it spreads to the north.(2)Based on the time series of the first and second modes obtained by EOF decomposition of the OLR,we caculate the annual mean amplitude variations of MJO in different seasons.The results show that the annual mean amplitude in spring and winter time is decreasing.but not obvious.There is a significant increasing trend in summer and winter.The trend in summer is stronger than that in autumn.(3)There is an evident seasonal variation in 1-2 phase and 7-8 phase by calculating the RMM index in different phases and different seaons.The result shows that MJO is active in 1-2 phase in spring and winter,and active in 7-8 phase in summer and autumn.In other words,the significant seasonal differences happenned in the generation and extinction time of MJO,and it has no obvious differences during the spread from west to east.(4)The oscillation period of the total column ozone(TCO)is about 30-60d in the Pacific Ocean.This paper analyzes the low-frequency ozone anomaly by using Lanczos band-pass filter.It finds out that with the higher latitudes,the chang is more obvious.The change in spring and winter is more obvious than that in summer and autumn.In the spring and winter,the anomalous increase of TCO happens in the middle and high latitudes,in the middle and low latitudes there are anomalous decrease.The positive changes in the equatorial areas are mainly negative.Just the opposite happenned in summer and autumn.(5)The anomalies of low-frequency TCO in the Pacific Ocean increase in each phase with the increase of the latitude.The anomalies especially obvious in phase 3-4 and 7-8.It is found that the anomalies of low-frequency ozone are less depend on the change of MJO phase in more than 20 hPa in stratosphere.It is more obvious in the middle and lower stratosphere and the maximal anomaly of ozone mass mixing ratio occurs at 30 hPa.(6)It has a correlation between the RMM index and the low-frequency ozone in the Pacific Ocean.The negative correlation is greater than the positive correlation,and the most obvious correlation is in phase 3-4 and 7-8.The significant correlation is becoming greater from the top to the bottom in stratosphere and the maximal correlation occurred at 100 hPa.(7)Based on the SVD analysis between the OLR data in phase 3-4 and 7-8 and the ozone data in the Pacific Ocean,we find that in phase 3-4 the low-frequency TCO decrease in the north of 40 ° N and increase in the south of 40 ° N when the MJO is active.And in phase 7-8 it is opposite.The relationship distribution in the stratosphere is different.The OLR is positively correlated with the low-frequency ozone in the north of 30° N and negatively correlated in the south of 30° N at 30 hPa and 50 hPa.While at 70hPa and 100hPa,the relationship distribution is similar to the low-frequency TCO.