Science Update: QBO Predictability and its northern hemisphere winter teleconnection on seasonal to decadal timescales

In a new GRL article, A. Scaife and co-authors examine the predictability of the Quasi-Biennial Oscillation (QBO) in initialised climate forecasts extending out to lead times of years using coupled ocean-atmosphere models with internally generated QBOs. They demonstrate the predictability of the QBO extending out to more than three years, with correlation scores exceeding 0.7 at a lead-time of 12 months. Predictability could be further improved through better initialisation and more realistic representation of the QBO, although this may depend on the realism of the gravity wave parameterisation used. They also show that predictability is lowest in winter and that skilful prediction of the QBO does not guarantee predictability of the extra-tropical winter teleconnection so important for surface winter climate prediction. The full abstract can be found here.

Science Update: A satellite perspective of the interaction between the QBO and gravity waves

M. Ern and co-authors present a new study in JGR using satellite observations to improve the representation of the quasi-biennial oscillation (QBO) in models. This improvement requires a better understanding of the driving of the QBO by atmospheric waves, which remains highly uncertain because of the small horizontal scales involved and because no direct estimation based on global observations yet exists. They derive gravity wave momentum fluxes from temperature observations form the HIRDLS and SABER satellite instruments, and show that waves with wavelengths <10km interact most strongly with the QBO. They estimate gravity wave drag and compare this to the missing drag in the tropical momentum budget of ERA-Interim. During eastward wind shear the observations agree well with ERA-Interim, however, during westward wind shear the observations are two times lower than ERA-Interim. This possibly suggests that uncertainties in the ERA-Interim advection terms remain. They find that the tropical gravity waves are strongly intermittent and thus may play in important role in terms of QBO formation. This may have important implications for gravity wave parameterisation in models. The full abstract can be found here.

New deadlines: CCMI meeting, Lancaster, May 2014

The second Chemistry Climate Model Initiative (CCMI) Meeting will be held in Lancaster, UK from 20-22 May 2014.

CCMI is a joint project of IGAC and SPARC with the aim to investigate and understand the historical and projected evolution of stratospheric and tropospheric composition and chemistry, including the links between those domains, and the feedbacks with the physical climate.

We are currently compiling already submitted abstracts, and we are expecting to announce our programme in the next week or so. In the meantime, we continue to invite abstract submissions on a broad range of topics related to chemistry-climate interactions, including from modellers, measurement scientists and data analysts.
More details, including registration can be found on the meeting website: http://www.lancaster.ac.uk/ccmi2014

FINANCIAL SUPPORT

Limited financial support is available to support attendance, with a preference for early career scientists and those coming from developing nations and countries in transition. Please see: http://www.lancaster.ac.uk/ccmi2014/support/

KEY DATES – ***PLEASE NOTE UPDATED DEADLINES***

Financial support deadline: 28th February 2014 (including abstract submission)

Abstract submission: 14th March 2014

Registration deadline: 1st April 2014

In addition, rooms in the meeting hotel can only be block booked for a limited time, so early accommodation booking is advised.

Science Update: Identification of downward propagation of Artic stratospheric climate change over recent decades

In a new Journal of Climate study, D.J. Ivy and co-authors examine changes in Arctic climate since 1979, focusing on the decadal scale. They show that dynamically quiescent years, with no major sudden stratospheric warmings, are marked by a strengthening of the Arctic polar vortex over the past 30 years. Associated changes, such as decreases in temperatures and ozone, propagate downwards into the lowermost Arctic stratosphere during late winter and early spring. This strengthening of the Arctic vortex appears to occur at higher altitudes than in the Antarctic and does not propagate as low into the troposphere, rather the signal remains confined to the uppermost troposphere. The full abstract can be found here.

Thank you for your contribution to the SPARC General Assembly

The 5th SPARC General Assembly has been a great success and most memorable event. Find information how to stay involved!

Dear GA participant,

On behalf of the SPARC Co-chairs Joan Alexander and Greg Bodeker, the local and scientific organising committees, as well
as the SPARC Office, we would like to warmly thank you for contributing to the great success of the 5th SPARC General Assembly held from 12-17 January 2014 in
Queenstown, New Zealand. The many excellent talks and posters presented at the conference as well as the lively discussions, learning opportunities, and great
fun we enjoyed together made this event most memorable!

We take this opportunity to once again welcome you to connect with ongoing and future SPARC activities and to inform you about the many ways you can stay in
touch with the rest of the community.

* We have uploaded all talks and abstracts to the conference website as well as a selection of photos:
http://www.sparc-climate.org/meetings/general-assembly-2014/
* Those of you interested in subscribing to the biannual SPARC newsletter should
subscribe right away – the January 2014 issue is due in the next week: http://www.sparc-climate.org/publications/newsletter/
* The news section and the
calendar on the SPARC website will keep you up to date: http://www.sparc-climate.org/news/news/ ; http://www.sparc-climate.org/meetings/ .

Please also keep us informed about events and activities in your region/country that might be of interest to the wider SPARC community.

With warm regards,

The SPARC Office

Science Update: Multi-model estimates of atmospheric lifetimes of long-lived ozone depleting substances: Present and future

A new JGR article by M. Chipperfield and co-authors highlights some of the modelling work that was done as part of the SPARC ‘Lifetimes of stratospheric ozone-depleting substances, their replacements, and related species’ Report (SPARC report no. 6). They diagnosed the lifetimes of long-lived source gases removed in the stratosphere using six 3D and one 2D model, which all used the same standard photochemical data. They investigate the effect of different lifetime definitions and find that different methods agree very well within the same model. Larger differences in lifetimes are calculated by different models, the main causes of which are variation in the simulated rates of ascent and horizontal mixing in the tropical mid-lower stratosphere. For 2100 conditions, the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modelled lifetimes is small. The abstract can be found here.