Interannual changes of stratospheric water vapor and correlations with tropical tropopause temperatures

Interannual anomalies in water vapor with an approximate 2-yr periodicity are evident near the tropical tropopause, and these propagate vertically and latitudinally with the mean stratospheric transport circulation (in a manner analogous to the seasonal "tape recorder"). Unusually low water vapor anomalies are observed in the lower stratosphere for 2001-03.

These interannual anomalies are also observed in Arctic lower-stratospheric water vapor measurements by the Polar Ozone and Aerosol Measurement (POAM) satellite instrument during 1998-2003. Comparisons of the HALOE data with balloon measurements of lower-stratospheric water vapor at Boulder, Colorado (40°N), show partial agreement for seasonal and interannual changes during 1992-2002, but decadal increases observed in the balloon measurements for this period are not observed in HALOE data.