Quart. J. Roy. Met. Soc. (2002), 128, 2301-2315.
The synoptic-scale variability of the polar and subpolar tropopause is investigated based on radiosonde and ERA data as well as on idealized PV inversions. A regression analysis is performed to examine the relations between the relative vorticity at tropopause level, the tropopause displacement, the static stability above the tropopause and the anomalies of tropopause temperature and potential tropopause temperature. The results are compared with regressions coefficients computed from a large number of PV inversions. \\ Generally, cyclonically influenced tropopauses are lower, warmer and potentially colder than average, and the static stability above the tropopause is reduced. The opposite is true under anticyclonic influence. Typically, a cyclonic vorticity of $10^{-5} \, \rm s^{-1}$ is associated with a decrease of the tropopause height by 100 -- 200 m. Correspondingly, the mean vertical temperature gradient in the lowermost 2 km above the tropopause decreases by 0.2 -- $0.3 \, \rm K \, km^{-1}$. Moreover, an increase of the tropopause height by 1 km is associated with a temperature decrease by 4 -- 6 K and an increase of the potential temperature by 5.5 -- 7.5 K. Except for the latter one, these values do not depend significantly on the strength and the sign of the tropopause anomaly. However, distinct annual cycles are observed in parts of the polar regions. Most of these relations can be reproduced well with the PV inversions, but the linearity for large tropopause displacements is not always captured as well. The annual cycles can be partly explained with the aid of the PV inversions.