Moisture condition in the South‐Eastern USA and teleconnection patterns

Abstract

AbstractThe purpose of this study is to investigate the relationship between the moisture condition and teleconnection patterns including the Pacific‐North American (PNA) pattern, North Atlantic Oscillation (NAO), and the El Niño‐Southern Oscillation (ENSO). The February and August Palmer's Drought Severity Index (PDSI) was used to represent the moisture condition of the cold and warm seasons in the south‐eastern USA. The teleconnection patterns were represented by the indices of PNAI, NAOI, and SOI. Composite maps for extreme values of the teleconnection indices revealed that spatial variation in the moisture condition is associated with different phases of the teleconnection patterns. Correlation analysis indicated that the PNA, NAO, and ENSO are related mostly to the subregional moisture conditions. Principal component analysis defined subregions of homogeneous moisture regimes. Then regression analysis was performed on the scores of the principal components of the February and August PDSI, using the teleconnection indices as the independent variables. The area with its cold‐season moisture condition best explained by the teleconnection patterns is central and south Florida. The teleconnection indices also explained significant portions of the variation in the cold‐season moisture condition of Mississippi and Tennessee. The teleconnection patterns in the previous autumn probably can be used to predict the moisture condition in the following winter. Compared with the cold season, the summer teleconnection patterns are less strongly related to the warm‐season moisture condition. Nevertheless, the relationships between the moisture condition and the teleconnection patterns are significant statistically. In addition, the teleconnection patterns in the previous spring offered some explanations to the spatial patterns in the warm‐season moisture condition in the region.