Principal sequence patterns of 1000 hpa geopotential height fields

COMPAGNUCCI R.; ARANEO D.

Whistler, BC, Canadá

Congreso; 7th International Meeting on Statistical Climatology; 1998

IMSC

A new aspect of T-mode Principal Components Analysis is used so as to obtain Principal Sequences Patterns of 1000 hPa geopotential heights. For the traditional tecnique, the correlation matrix (R) is obtained by regarding spatial fields as variables (m) and time series from the network as observations (n). This turns out a matrix R:mxm, whose entries are the correlation among variables. The (standardized) Components Scores are the new variables and represent type-fields and the corresponding Component Loadings give the correlation time series between those and the original variables from the analysed sample. In this application each variable is a sequence of daily 1000 hPa geopotential height field. When k sequences are analysed from a m-daily fields and n-network pints data set, the input matrix has got (m-k+1) variables and (km) observations. Each standardized Components Score is formed by k-fields of the type-sequence and the corresponding Component Loadings time series means the correlations between each type-sequence and each k-fields sequence from the original dataset. The analysed dataset come from the Servicio Meteorológico Nacional Argentino (SMNA) Diagnostic Model Analysis covering the Southern Cone of South America. Different trials on 3, 5 and 7 day-sequences are made. The results show the significative type-sequence number is similar to the number of significative patterns obtained by regarding the traditional technique with the single-fields as variables. Principal Sequence Patterns envolve those patterns obtained through the use of single-field Analysis. The longer time sequence is (i.e. k increases), the lower explained variance is for the first type-sequence increasing the explained variance for the type-sequence of superior order. The Component Loading time series corresponding to the type-sequences and those from single-fields Analysis are alike. The resulting type-sequences show the time behaviour of the more frequently synoptic patterns. It can be reckoned and identified blocking situations, cyclogenesis, anticyclogenesis and systems passages. Same technique will be applied for different geopotential height together from 1000 hPa to 200 hpa regarding all the levels as one single variable in order to analyse 3D-space behavior.