MOISTURE CONDITION IN THE SOUTH-EASTERN USA AND TELECONNECTION PATTERNS

The purpose of this study is to investigate the relationship between t he moisture condition and teleconnection patterns including the Pacifi c-North American (PNA) pattern, North Atlantic Oscillation (NAO), and the El Nino-Southern Oscillation (ENSO). The February and August Palme r's Drought Severity Index (PDSI) was used to represent the moisture c ondition of the cold and warm seasons in the south-eastern USA. The te leconnection patterns were represented by the indices of PNAI, NAOI, a nd SOI. Composite maps for extreme values of the teleconnection indice s revealed that spatial variation in the moisture condition is associa ted with different phases of the teleconnection patterns. Correlation analysis indicated that the PNA, NAO, and ENSO are related mostly to t he subregional moisture conditions. Principal component analysis defin ed subregions of homogeneous moisture regimes. Then regression analysi s was performed on the scores of the principal components of the Febru ary and August PDSI, using the teleconnection indices as the independe nt variables. The area with its cold-season moisture condition best ex plained by the teleconnection patterns is central and south Florida. T he teleconnection indices also explained significant portions of the v ariation in the cold-season moisture condition of Mississippi and Tenn essee. The teleconnection patterns in the previous autumn probably can be used to predict the moisture condition in the following winter. Co mpared with the cold season, the summer teleconnection patterns are le ss strongly related to the warm-season moisture condition. Nevertheles s, the relationships between the moisture condition and the teleconnec tion patterns are significant statistically. In addition, the teleconn ection patterns in the previous spring offered some explanations to th e spatial patterns in the warm-season moisture condition in the region .