The Unusual Northern Polar Summer of 2002

byRichard A. Goldberg (NASA GSFC)

Artem G. Feofilov (CUA/GSFC)Alexander A. Kutepov (CUA/GSFC)

W. Dean Pesnell (NASA GSFC)F. J. Schmidlin (NASA GSFC)

andJames 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<Tfrost and water vapor is abundant, water ice forms.

• Ice particles precipitate and sublimate when T>Tfrost.

• This transition is very sharp and it traces the mesospheric temperature.

Tfrost ~ 1 / ln( / [H2O])

The SABER instrument aboard

the TIMED satellite TIMED: Thermosphere, Ionosphere, Mesosphere Energetics & Dynamics

Latitudinal coverage Example of an orbit

Mission launched on December 7, 2001Data available since January 25, 20024 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 (~10-100 km, ~2 km footprint)

• 10 broadband channels (1.27-17 µm)

• Products: kinetic temperature, CO2, O3, H2O, NO, O2, 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 151-213) 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 – 35 53 88

2003 – 50 59 109

2004 – 67 56 123

2005 – 45 51 96

2006 – 50 50 100

2007 – 49 52 101

2008 – 57 64 121

Comparing temperatures in 2002 and 2003-2008

Temperature distribution in July 2002 Temperature distribution in July 2003-2008

Temperature difference 2002 – {2003-2008} Temperature deviations 2002 vs {2003-2008}

T - Tave (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.