Science Update: Validation of global ozone profile measurements

In their JGR article, Koji Imai and numerous SPARC scientists as co-authors, present validation studies of ozone profiles in the middle atmosphere.

The data was taken by Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station ISS from October 2009 to April 2010. Comparisons of the data with satellite observations and chemistry-transport models indicate that the observations agree generally within 10%. The SMILES data also capture diurnal variability well.

Find the full article here.

Science Update: The importance of time-varying forcing for Quasi-Biannial Oscillation modulation of the atmospheric 11-year solar cycle signal

In their JGR article authored by SOLARIS-HEPPA activity leader Katja Matthes and colleagues, the results are presented from multi-decadal sensitivity experiments with time-varying solar cycle and Quasi-Biennial Oscillation (QBO) forcings.

Multi-decadal simulations using the NCAR’s Whole Atmosphere Community Climate Model (WACCM3.1) were carried out to assess the time-varying forcing of solar variability and the QBO. In the tropical upper stratsphere the annual mean solar response is found to be independent of the presence of the QBO. Only the experiment including both solar and QBO forcing agrees reasonably with observations, indicating that both forcings are necessary to realistically simulating the climate. The QBO is also found to modulate the background zonal mean wind climatology, which in turn modifies the modelled solar signal.

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Science Update: Combined SAGE II-GOMOS ozone profile data set 1984-2011 and trend analysis of the vertical distribution of ozone

A new, homogeneous long-term data set of vertical ozone profile observations has been compiled using SAGE II and GOMOS observations. The combined data set covers latitudes 60°N-60°S and the altitude range of 20-60km (at 1km vertical resolution) for the period 1984-2011. Trend analysis of the data indicates that in equatorial regions at altitudes of 38-45km the negative ozone trend observed from 1984-1997 has reversed to a small positive trend of 0-2% per decade. In the 30-35km range, however, ozone loss has increased. At mid-latitudes a similar trend reversal is observed, with the negative trend prior to 1997 (-4-10%/decade) also becoming a small positive trend (0-2%/decade).

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Science Update: Volcanic sulfate deposition to Greenland and Antarctica: a modeling sensitivity study

In their JGR publication co-authored by SPARC scientist Claudia Timmreck, SSiRC activity leader, the assumption is tested using the MAECHAM5-HAM global aerosol-climate model that the atmospheric burden and deposition of volcanic sulfate aerosol are directly proportional. The deposition efficiency is found to depend on the magnitude and season of stratospheric sulfur injection. Eruptions with large SO2 injections are associated with increases in aerosol particle size, which influence sedimentation velocity and radiative properties, which in turn lead to dynamic changes including a strengthening of the winter polar vortices. This strengthening inhibits stratospheric aerosol transport to high latitudes and, for very large eruptions, a non-linear relationship of sulfate deposition is observed between Antarctica and Greenland (with sulfate deposition over Antarctica). These results may be of significance when interpreting ice core sulfate measurements.

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SPARC General Assembly: Abstract submission now open

The 5th SPARC General Assembly will bring together hundreds of experts to discuss and assess the emerging role the stratosphere plays in the climate system, including chemical climate modelling with a focus on tropospheric chemistry will be presented.

This event will take place from 12-17 January 2014 in Queenstown, New Zealand. Abstract submission is now open. Travel support for early career scientists and scientists from emerging and developing countries is available, please see the website for further details on how to apply..

Find a description of sessions; submit your abstract; go to conference website.

Abstract deadline: 13 April – IAGA 2013 Scientific Assembly

Of particular interest to the SPARC community is the session on IAMAS-ICMA middle atmosphere science at the upcoming IAGA 2013 Scientific Assembly, to be held 26-31 August 2013 in Mérida, Mexico.

Invitation by Dan Marsh, Andrew Charlton-Perez, and O. Morgenstern Session conveners

2.5 Middle atmosphere science

Papers related to any aspect of the dynamics, chemistry, or physics of the atmosphere from near the tropopause to the lower thermosphere are appropriate for this session.

Observational, modeling and theoretical papers are all solicited. Research topics include (but are not limited to): multiple-scale dynamics and mixing, observations and modeling of gravity waves, stratospheric chemistry and ozone, microphysics, chemistry and dynamics of the UTLS, and intraseasonal and interannual variations in the middle atmosphere. In particular, investigations of the middle atmosphere in the context of climate of the whole atmosphere are encouraged.

Other ICMA sponsored sessions:

J10Div. II/III/ICMA Energetic particle precipitation into the atmosphere: sources and consequences

2.2 Div II/ICMA Electrodynamics and energetics of the middle atmosphere and lower thermosphere: the local and global picture

2.3 Div II/ICMA Coupling Processes in the Atmosphere-Ionosphere System

2.4 Div II/ICMA and CAWSES-II/SCOSTEP Long- and short-term solar influences in the middle and upper atmosphere

Find second circular; find conference website.