Characteristics Of Typhoon Convection In The Changing Characteristics Of West Pacific Warm Pool And Its Humidity

The western Pacific warm pool is an important factor in regulating the tropical Pacific and even the global climate.Because its sea surface temperature is higher than other sea surface temperature,thus gathered a lot of energy,and has a certain influence on the occurrence,development,path and quantity of tropical cyclones.There is a close connection.Therefore,it is of great scientific and practical significance to study the variation of humidity and the characteristics of typhoon convective structure in the western Pacific warm pool under different thermal conditions.At present,the application level of satellite remote sensing data is not high enough to fully exploit the advantages of satellite remote sensing data in sea observation.The research on the response of the western Pacific warm pool to typhoon convection based on satellite remote sensing is of great scientific significance.This paper mainly uses the data of Fengyun-3 satellite microwave hygrometer and ERA-Interim reanalysis data.Based on the empirical orthogonal function method and wavelet analysis method,the characteristics of the western Pacific warm pool are studied.The use of microwave hygrometer data to detect the typhoon development process and the analysis of typhoon convective structural types and the characteristics of moisture distribution under different thermal conditions in the western Pacific warm pool,the influence of the western Pacific warm pool anomaly on the convective structure of typhoon was investigated.The main research results of the paper are as follows:(1)The longitude of the eastern boundary of the western Pacific warm pool can respond well to the occurrence time and intensity of the ENSO events.The east boundary area index of the warm pool can respond well to occurrence time of ENSO events,but the response to the intensity is less than the longitude of the east boundary of the pool,but the response to the intensity is not as good as that of the east boundary of the warm pool.The main modes of the SST field in the warm pool sea area are interannual and interdecadal variations.The first mode can well predict the occurrence of ENSO.Through the wavelet analysis,it can be seen that the eastern boundary of the warm pool has the same cycle as the ENSO,and the warm pool east boundary and the ONI index have a 1/8 cycle lead relationship.Therefore,the zonal movement of the warm pool has better predictive significance to the occurrence of ENSO.(2)By analyzing the typhoon data of 26 times by microwave hygrometer,roughly three types of bright temperature profiles can be drawn.Through the comparison of the three types,it can be seen that the first type is the conventional type,and the low-level of water vapor Adequate,relatively humid,and the middle and upper atmospheres are relatively dry.At this time,the tropical cyclones are basically typhoon level.The intensity is basically not yet strong and the strength is maintained.The second type of low atmosphere is more dry,and the 800 h Pa layer of moisture is relatively humid.,the middle and upper atmospheres is still relatively dry.At this time,the tropical cyclone is basically a strong typhoon level.Its intensity is basically in a mature state,its strength is maintained or it is ready to be strengthened.The third type of low atmosphere is drier,the atmosphere at 800 h Pa is slightly moist,and the middle and upper atmosphere is relatively humid.Tropical cyclones are not strong at this time and are in a ready-enhanced state.(3)There are obvious differences between the three types of typhoon convection at 800 h Pa,which may result from the difference of water vapor inflow and outflow.Both the first type and the second type are turned dry in the middle and upper layers,but there is a slight difference in humidity between the two at 600 h Pa.The second type is more wet than the first type.(4)When the western Pacific warm pool is abnormally warm,the relative humidity in the warm pool area is much higher,the range is extended in the longitude,and the convection activity is enhanced,which makes the water vapor in the atmosphere is relatively sufficient,which provides favorable conditions for the development of the typhoon.The microwave hygrometer analyzes the internal structure of the typhoon "Salijia".The typhoon has the widest temperature and peak-to-valley range near the 800 h Pa channel,and the brightness temperature is near the 800 h Pa in the temperature and temperature profile map.Therefore,the microwave hygrometer can clearly distinguish different levels of the typhoon.The distribution of the distribution is shown,and it corresponds well with the brightness temperature profile and is similar to the second type of typhoon convection structure.(5)When the western Pacific warm pool is abnormally cold,the relative humidity of the warm pool region is correspondingly small,and the range has expanded in latitude,but the convective activity is weakened and it is not conducive to the development of the typhoon.The internal structure of the typhoon "Lotain" was analyzed by a microwave hygrometer.The bright temperature profile of the typhoon "Lotain" increased with height,that is,the humidity decreased with increasing height.The microwave hygrometer can clearly show the distribution of different levels of typhoon,and it can correspond well with the brightness and temperature profiles,which is similar to the first type of typhoon convection structure.Therefore,the microwave hygrometer has a good monitoring capability in monitoring typhoons,indicating that the three types of typhoon convection structures have certain feasibility.