The Unusual Northern Polar Summer of 2002 by Richard A. Goldberg (NASA GSFC) Artem G. Feofilov (CUA/GSFC) Alexander A. Kutepov (CUA/GSFC) W. Dean Pesnell (NASA GSFC) F. J. Schmidlin (NASA GSFC) and James M. Russell III (Hampton University) 19th ESA Symposium on European Rocket and Balloon Programmes and Related Research 7-11 June 2009; Bad Reichenhall, Germany

Outline of Talk  First review some of the effects seen during MaCWAVE/MIDAS as the motivation for this work.  Introduce the SABER instrument on TIMED.  Show results encompassing the first seven years of SABER operation.  Show how the results confirm theoretical studies suggesting hemispheric coupling from the southern to northern hemisphere, initiated by a stratospheric warming

Anomalous summer: first signs

2002 exhibits significantly fewer events and a shorter occurrence period because of a later start than in the other years. Latteck (2008) ALOMAR PMSE occurrence rates

Water vapor as a tracer of trends in polar summer mesosphere If the T<T frost and water vapor is abundant, water ice forms. Ice particles precipitate and sublimate when T>T frost. This transition is very sharp and it traces the mesospheric temperature. T frost ~ 1 / ln(  / [H 2 O])

The SABER instrument aboard the TIMED satellite TIMED: Thermosphere, Ionosphere, Mesosphere Energetics & Dynamics Latitudinal coverageExample of an orbit Mission launched on December 7, 2001 Data available since January 25, instruments: GUVI, SEE, TIDI, SABER

The SABER instrument aboard the TIMED satellite SABER: Sounding of the Atmosphere Using Broadband Emission Radiometry SABER instrument: Designed to study the Mesosphere and Lower Thermosphere (MLT) Limb scanning infrared radiometer (~ km, ~2 km footprint) 10 broadband channels ( µm) Products: kinetic temperature, CO 2, O 3, H 2 O, NO, O 2, OH, O, H

Approach  The complete V1.07 dataset currently available was analyzed.  The dataset was used to build the temperature distributions for the summer period in northern hemisphere (days ) and to trace the mesopause position and temperatures.  The data for temperature distributions was averaged zonally and gridded into 2 degree latitude and 2 km altitude bins.  Individual temperature profiles were averaged zonally and daily within 2 degree “belts” around 82S, 51S, 51N, and 82N.  These averaged profiles were used to determine mesopause altitude and mesopause temperature values.

Mesopause temperature and NH polar summer duration Approximate frost point

Polar summer duration Year  (Start – Solstice), days  (End – Solstice), days Duration, days 2002– – – – – – –

Comparing temperatures in 2002 and

Temperature distribution in July 2002Temperature distribution in July Temperature difference 2002 – { }Temperature deviations 2002 vs { }

T - T ave (K) sequence: June-July, 2002

Conclusions  The warming of the northern summer polar mesopause region in 2002, as noted from MaCWAVE/MIDAS data, appears to have been a global effect in that hemisphere, when viewed by SABER.  Duration of the polar summer was also reduced, leading to a lower frequency of occurrence for PMSEs and NLCs.  Southern winter during July 2002 shows a heating of the stratospheric region consistent with the occurrence of a sudden stratospheric warming (SSW). This produced southern mesospheric heating plus a transfer of energy to the northern hemisphere, where it heated the polar mesospause region.  The maximum effect of the transfer suggested to be Rossby waves (Becker et al., 2004) occurred 1-2 weeks after the SSW.  The results are consistent with the theoretical modeling of Larsson et al. (2008) who predict that a stratospheric warming in the southern hemisphere would induce a more stable, warmer polar mesopause region in the northern hemisphere.  This study demonstrates how the measured results first obtained by MaCWAVE/MIDAS in the summer of 2002 led to further identification of global effects induced by hemispheric coupling and verified from the SABER instrument aboard TIMED.