The Research On Spatial Constructions Of Climate System And Decadal Cooperation Of Teleconnections

Temperature and height correlation networks are constructed based on NCEP/NCAR reanalysis data,using correlation matrix analysis methods and complex networks theory.Face problems in climate system complexity:(1)only negative correlations are considered and focus on just one or two teleconnections in traditional research,which can't give a whole view on the spatial characteristics of climate system;(2)Difference of SLP in different places is used in the definition of teleconnection index in traditional way,which can't show the acting extent of teleconnection to the climate system;(3)Few works on decadal cooperation of teleconnections and their correlations with climate changes in China,we make some primary discussion.Main conclusions are as following:(1)Correlations of global temperature and its temporal and spatial characteristics is analyzed based in probability statistical way.Noise and true correlations both existed in global temperature field,which contains short and long distance correlations i.e.Pacific decadal oscillations(PDO).Mean correlation coefficients show different status near 1977,which correspond to the temperature abrupt change in 1970s.Zonal spatial distribution of correlations coefficients are presented both in 1d and 30d scales,and coefficients in tropical Pacific,Indian ocean, Atlantic and north Pacific are all abnormal correlation places.Correlation research in global temperature field established the foundations of the construction temperature correlation networks.(2)Characteristics of structure of spatial correlations in temperature and circumfluence systems.Correlation networks of temperature and circumfluence is constructed,both of these two kinds of network shows small world effect,that is to say large number of short distance connections ensure the structure stability of system, a few number of teleconnections improve the information transfer efficiency.Degree distribution differences show that spatial structure of middle and low latitude systems are quite different,and the exact boundary of circumfluence is at 27.5N and 27.5S. Average degree of low latitude circumfluence network is comparatively larger and synchronization is better than that of middle latitude,so spatial characteristics of low latitude circumfluence network presents the property of global coupling networks. Furthermore,Average degree of middle latitude circumfluence network is comparative smaller;however degree of some area is rather lager,which show that middle latitude network have typical small world property.(3)Definition of tropical pacific temperature correlation index(TPTI) and teleconnection action index(TAI).Degree denotes the action importance of point in the network,so TPTI and five kinds of TAI is defined by calculating the area average degree,and then a new index system for teleconnections and tropical pacific temperature is established.Obviously,physical mean of TPTI is better than that of traditional abnormal Sea Surface Temperature(ASST).Besides,Lager TPTI often correspond to the robust El nino or La nina signal which indicate that it is not equal between robust signal and action for the key area in the climate system.TPTI applied in the research of summer precipitation in China,results show that correlation coefficients between summer/spring TPTI and the temporal series of first mode of summer precipitation is-0.35 and-0.34,so TPTI might be used in prediction of China summer precipitation.Five kinds of TAI show the corresponding teleconnections' action in the climate system,which is also helpful in confirming the leading mode of middle latitude circumfluence in different decadal.(4)Teleconnections' influence on the structure of circumfluence system.In the middle latitude circumfluence system of north hemisphere,short and long distance connection all decreased by filtering out AO and NAO,and the average path length distinctly increased,and the influence of AO is comparatively lager than that of NAO. While PNA is rather a separated teleconnection in the system,its action most denotes the correlations between middle and low latitude system.In the middle latitude circumfluence system of south hemisphere,AAO is the most important mode, filtering out AAO the average degree of middle latitude circumfluence network of south hemisphere decreased 45%,and the average length increased 34%.We find a obvious dipole in Antarctic Arctic(AAD) with 500hpa height data,which is also existed in 200hpa and 800hpa.AAD might correspond to a new teleconnection haven't been paid much attention,however it has definitely influence on AAO and the middle latitude circumfluence system of south hemisphere.(5)Research on characteristics of decadal leading teleconnections.Decadal characteristics for PNA,NAO,AO,EUPA and WP might be presented from two sides: (1)moving of action centre,action centre of NAO,EUPA and WP all moved during different periods in last 40 years and there was a common abrupt change process during 1970s;while the mode of PNA is comparatively stable and moving of action centre is also quite small,which further indicate that PNA is a separated teleconnection in middle latitude system in north hemisphere.(2)Leading modes of teleconnection is confirmed based on the TAI:the leading mode is PNA,EUPA and WP before 1976;action of NAO notably increased and all the five teleconnections are comparatively robust after 1977;action of AO notably increased and other modes are comparatively weaker after 1985.(6)The construction of physical statistical and factors coupling model and its application to China summer precipitation(CSP).Correlation between TAI and CSP base on the decadal scale,and based on the influence factors CSP been divided into 10 characteristic areas.Furthermore,physical and statistical model of CSP been established based on the factors coupling and a new method for CSP prediction is put forward.Factors coupling,using decadal data to estimate annual data,history similar information et al.is considered in this prediction method,numerical test show that this way can efficiently used in CSP prediction.