observed in HALOE data (1991-2004)
The HALOE satellite instrument has made near-global measurements of stratospheric
water vapor covering 1991-2004 (continuing at present). The following plot shows
time series of global averaged HALOE measurements at 82 hPa (near 18 km) for the
entire 1991-2004 record (each point represents one month of data). The data have
been deseasonalized (by subtracting a mean annual cycle) to highlight interannual
changes. Note the approximate 2-year periodicity in the deseasonalized data, plus the
persistent, anomalously low values during 2001-2004.
This following figure shows a height-time plot of the the deseasonalized anomalies in
stratospheric water vapor (actually H2O+2*CH4) over 20 N-20 S. The anomalies with
an approximate 2-year periodicity originate near ~100 hPa, and propagate vertically
with the mean stratospheric circulation (analogous to the seasonal 'tape recorder').
These water vapor changes observed by HALOE are in good agreement with independent
measurements by the Polar Ozone and Aerosol Measurement (POAM) satellite for
1998-2004, and the HALOE data are also well correlated with temperature anomalies
near the tropical tropopause.
For lots of details, including comparisons with Boulder balloon measurements,
see our new paper:
Interannual changes in stratospheric water vapor, and correlations
with tropical tropopause temperatures
W. Randel, F. Wu, S. Oltmans, K. Rosenlof and G. Nedoluha,
J. Atmos. Sci., 61, 2133-2148. pdf file