Title: RELATIONSHIPS BETWEEN GEOPOTENTIAL HEIGHTS AND TEMPERATURE IN THE SOUTH‐EASTERN US DURING WINTERTIME WARMING AND COOLING PERIODS
Abstract: This paper discusses the relationship between geopotential heights and mean winter surface temperature and the characteristics of interannual variability in the south-eastern USA during cooling and warming periods from 1946 to 1992. Data from 83 Historical Climatology Network stations in 12 south-eastern states were examined. Factor analysis was used to separate the south-east into three climatic regions. These regions were then matched with both 500 hPa and 700 hPa pressure heights during two periods: the 1946–1976 cooling period and the 1976–1992 warming period. The degree of association between geopotential heights and surface temperature was greater during the cooling period than during the warming period. Possible influences may lie with differential temperature modification effects of the Gulf of Mexico and Atlantic Ocean, as well as soil moisture variability. The amount of geopotential height variability, as measured by standard deviations, was also compared between the cooling and warming periods, and was significantly greater during the cooling period. This explains a similar pattern in the surface temperature variability. A possible cause is the susceptibility of troughs to prolongation and amplification during cold winters. Both results suggest that not only is it difficult to determine the forcing mechanisms that cause short-term variability, but that the influence of the forcing mechanisms may not be consistent between cooling and warming periods as well.