Sea-level pressure–air temperature teleconnections during northern hemisphere winter

Abstract

The relationship between sea-level pressure (SLP) and 1,000 hPa air temperature (AT) in winter is investigated over the northern hemisphere, and a statistical forecasting of one of the two parameters from the other is attempted on a monthly basis. Mean monthly SLP and 1,000 hPa level AT values at 563 grid points over the northern hemisphere are utilized for January, February and March, for the period 1949–2002. At first, factor analysis is applied to the data sets as a dimensionality reduction tool. Then, canonical correlation analysis is applied to the resultant factor scores time series for the five SLP–AT pairs: SLP(J)–AT(J), SLP(J)–AT(F), SLP(J)–AT(M), AT(J)–SLP(F) and AT(J)–SLP(M), and the synchronous and time-lag connections between the two parameters are investigated. The areas characterized by a satisfactory monthly or/and bi-monthly forecasting ability are detected. The most satisfactory results refer to the areas affected by the Southern Oscillation. It is found that the SLP teleconnection between the areas of the eastern and the western Pacific in January is related to the regime of AT in the central Pacific Ocean, in both February and March. Also, SLP over the Aleutian and Icelandic lows in January is related to AT over their southwestern and southeastern neighbouring areas in February and March. Finally, it appears that there is also ability for monthly/bi-monthly statistical prediction for some areas affected by the well-known oscillations of North Atlantic Oscillation and Pacific/North American Oscillation. A validation of the statistical prediction methodology is carried out, using real-time series of AT and SLP parameters for some characteristic cases. The results show that the statistical prediction presents a remarkable success. The success rate varies from 67% to 83% for the analysis period 1949–2002 and from 71% to 86% for the recent period 2003–2009.