Report - NCAS Atmospheric Science Conference, Manchester, UK, 5-7 July 2010

The HMEI Secretariat, B. Sumner and C. Charstone, attended this meeting with the aim of expanding the HMEI contacts with scientists, experts and manufacturers into specialised areas of the industry beyond its current range. C. Charstone prepared and presented a poster informing participants of the work of HMEI. The Secretariat also prepared the following report on the meeting, which focuses on items the HMEI Secretariat believes to be of the most interest for HMEI Members and is not intended to be definitive.

  OPENING
Professor Stephen Mobbs, the Leeds Director of the National Centre for Atmospheric Science (NCAS), opened the meeting after a buffet lunch hosted by NCAS and welcomed the attendees.

Plenary Session 1 - JOINT SESSION WITH NATIONAL CENTRE FOR EARTH OBSERVATION

Viewing Atmospheric Moist Processes from Space as a Test of Our Understanding of the Planet's Hydrological Cycle - Graeme Stephens - Colorado State University
This paper looked at:

• Observed problems in precipitation as predicted by models and thus for modelling the coupled Earth system, as the models are not near reality in rainfall prediction.

• This has led to doubts about whether there is something missing from the theory of how Cb Hot Towers transport moisture in the atmosphere.

• There is a need to include better observations in regard to frequency and intensity of precipitation in the climate models to try and resolve this.

• There are significant biases in key Model moist physics parameters.

• A-Train cloud profile sensors resolved data can complement the current Hot Towers theory.

Remote Sensing of Icelandic Ash Plume - Alan Vance - Met Office
As models can only be as good as the data input this paper looked at the experience of the Met Office of looking at the composition of the ash plume from the recent volcanic eruption over Europe. In comparing the various observations the Met Office used when looking at the plume, the presentation noted:

• Ash retrievals from IASI observations - this showed ash plume well, distinguished from clouds.

• SO2 was also shown in IAS1 observations.

• IASI  gas retrievals were compared against airborne LIDAR.

• This was a comparison of IASI and ARIES (an airborne inferometer) with LIDAR observations.

Conclusion:

• The composition of a volcanic plume is complex. Thus no single component is sufficient in observing and tracking a volcanic plume.

• LIDAR and satellite observations are not sufficient alone.

• High resolution sounders (such as IASI) are also necessary for the best picture of the volcanic plume and its dissemination.

LIDAR measurements of volcanic ash - Geraint Vaughan - NCAS, Manchester
The Capel Davis Raman LIDAR was predominantly used. The results from observations in this instance were:

• Ash was found in thin moist layers.

• There were much higher LIDAR ratios than previously reported. Thus implying the ash particles were not spherical.

•  Dramatic varying Optical Depth (OD).

Current Changes in Tropical Precipitation - Richard Allan, Reading  (See document here)
It was noted that models indicate that with the increase in Greenhouse Gases and thus atmospheric warming  1) wet areas will get wetter and 2) dry areas will get dryer. However there is a stabilizing effect of enhanced Greenhouse Gases.

The presentation looked work done on the actual observations from 1979 to 2002 comparing to reanalysis of data into prediction models for that period.

It was found that:

• In regard to intensity of rainfall in atmospheric warming, there was not good correlation between the models and the real observational data.

• Extra Tropics and wet regions of Tropic get wetter.

• Dry regions get dryer.

Outstanding Issues identified were:

• Inaccurate simulation of precipitation events,

• Limits of satellite and gauge data.

• Detecting and attributing signals.

• Cloud feedback.

• Aerosol.

Tracer Correlations and probability density functions as touchstones for CCM (Climate Change Models) - Peter Braesicke, NCAS, Cambridge
The presentation looked at confronting models with actual observations, which the authors considered essential to improvements in models.

What can we learn about clouds and their representation in models from the synergy of radar and LIDAR observations? - Robin Hogan, Reading (See link to powerpoint presentation here)
Looking comparatively at data from space-borne radar, Lidar and radiometers in the A-Train and CERES and the way the different methods can complement each other, this presentation found that:

• Compared to Radars, Lidar was more sensitive to thin and liquid clouds, but attenuated.

• Synergized Radar and Lidar data can create less bias in the data overall.

The resulting issues are:

• Could retrievals improve weather forecasts?

• Could be used to improve climate models?

• If the answer to these questions is yes, then:

• should derived cloud products (from multi-modal satellite observations) be used in the model assimilations?
  or

• should the radar and Lidar observations be used directly?

Plenary session 2 - CLIMATE & EARTH SCIENCE (part 1)

Engineering climate on a regional scale (why it can't be done) - David Battisti, University of Washington, USA
Geo-engineering schemes hope to minimize, reduce or alter the effect of climate change by changing the properties of our environment. Geo-engineering methods either try to directly reduce the amount of carbon dioxide in the atmosphere - known as carbon sequestration - or they look to modify the earth's solar reflectivity cooling the planet by increasing the amount of sunlight reflected back to space.

Modelling Results:

• Modifying the earth's solar reflectivity by an input of sulphate aerosols into the stratosphere, is a method that has been verified as effective by running model simulations.

• Results in modelling for geo-engineering to the same temperature as now, but with double CO2, shows there are still many problems, some hotspots (i.e. +4 degrees centigrade) and some depletion of sea-ice and ice thickness decreases.

• Changes in ocean circulation has large impacts on engineered summer ice thickness.

Problems:

• Uncertainty as to how much aerosols should be added to the stratosphere?

• The response  for ocean change is ~ 100 years.

• The need to keep deploying the geo-engineering..

Conclusion: Geo-engineering is NOT the solution.

Transient simulations of the last glacial cycle with an AOGCM - Robin Smith, Reading
Looking at simulations from the Antarctic climate data from ice cores this presentation noted:

• The problem is to extrapolate the Antarctic climate record (~ 120,000 years) to a full global climate model, which would explain the Antarctic record.

• Need to know which are the forcings are the most significant: solar insolation, GHGs or ice sheet thickness?

• These were looked at individually and in different combinations.

The conclusions did not clarify that any one forcing was more important, rather it seems to be a combination of all the forcings which are significant together.

Self -aggregation in idealized simulations of tropical simulations - Steve Woolnough, NCAS, Reading
The presentation explained the self-aggregation process and looked at trying to explain why the Cascade simulation shows self aggregation occurring twice as fast as in the Bretherton model.

A Multi-model assessment of intercontinental source-receptor relationships for ozone pollution in the 21st century - Ruth Doherty, Edinburgh (Abstract of document available here)
The hypothesis on which this experiment started was:

• assuming a 20% emissions reduction in the 2090's, resulting in reduced ozone amounts:

• in a source region there is a slightly greater response of ozone decrease than downwind of the source region.

Conclusions:

• Additional emission controls needed, to maintain present day ozone air quality standards in the future.

• A greater effect of emission controls in the source region, but lesser effect downwind due to reduced ozone and ozone-precursor export.

Where should UK climate science go from here?  - John Mitchell, Met Office, UK
Dr Mitchell acknowledged that there is still  a lot not known in climate science when looking into the future. As a result the various models of future rises in CO2 have large uncertainties between the various models.

He stressed that adaptation to climate change was necessary, given the apparent inability of being able to reduce the rising CO2 levels. Adaptation needed to be particularly based on the changes predicted in precipitation. Models for the UK predict an overall drop in precipitation in the summer.

Dr Mitchell noted that Geo-engineering was a very complex idea about which not enough was known and to attempt to change some regional problems by such means (for example cloud seeding) would result in unexpected and probably negative results in the surrounding areas.

In his concluding remarks Dr Mitchell noted amongst other things :

• Resolution does not solve all the problems.

• Satellite data - radar and Lidar will give extra input to the models.

• Biochemical factors introduce further uncertainties and these processes are not well understood.

PLANETARY SESSION 3 - ATMOSPHERIC COMPOSITION (part 1)

Atmospheric chemistry in volcanic plume - Roland von Glasow, University of East Anglia, UK (See document here)
This paper looked at simulations done with a model setup is based on observations using MAX-DOAS (Multi Axis Differential Optical Absorption Spectroscopy) from Mount Etna, Sicily.

Conclusions:

• Bromine in the plume leads to considerable O3 (ozone) loss

• Bromine concentration also leads to large Mercury depletion

• Large uncertainties in results means there is a need for further study.

PLANETARY SESSION 4 - Technology for observing and modeling the atmosphere  (part 1)

The Facility for Ground based Atmospheric Measurements (FGAM): highlights and activities - James Hopkins, FGAM, York (See document here)
This facility provides observations for NCAS . There are seven observatories with links to the facility, listed below:

• The Cape Verde Atmospheric Observatory (CVAO)

• The Capel Dewi MST radar

• The Cardington Field Site

• The Chilbolton facility for Atmospheric and Radar Research (CFARR)

• The FAAM aircraft as a long-term observatory

• The Salford Urban Built Environmental Research Base site (SUBERB)

•  The Weybourne Atmospheric Observatory (WAO)

The FGAM provides the observations for NCAS work in 4 areas:

• Atmospheric observations

• laboratory studies

• Ground Based/ File observations

• Airborne observations

Important for each of the observation areas is the FGAM work on:

• Collaborations;

• Data Provision;

• Long term studies; and

• Intercalibration

For further information on FGAM, including their campaigns, please go to the website at: http://www.ncas.ac.uk/fgam/

Quality of atmospheric water vapour measurements using instrumentation on board the FAAM BAe-146 research aircraft - Debbie O'Sullivan, Met Office , UK
Dr O'Sullivan has used observations from the FAAM BAe146-301 research aircraft to study the impact of aerosols on atmospheric radiation. These aircraft measurements are compared with radiative transfer models to assess the model's performance and achieve an improved understanding of aerosols and their radiative impacts. In this document Dr O'Sullivan outlined Future Plans for the FAMM BAE-146 instrumentation for observations of atmospheric water vapour for the Met Office Observation Based Research. Updates will include: a more stable lamp to resolve impurities in spectrum; introducing a second ly-α detector; improving the ability to measure in more humid conditions, as well as dry; and so forth.

More information about Observation Based Research at the Met Office is available at: http://www.metoffice.gov.uk/research/areas/observational-studies.

CEDA's role in the Icelanic volcanic Ash cloud research  - Wendy Garland, BADC
CEDA can support rapid response programs such as this one recently regarding the ash cloud in Iceland. CEDA's volcano event log mapping tool enabled researchers to find information and data they needed rapidly and reliably. See: http://cedaapp1.badc.rl.ac.uk/

The work of the BADC can be seen at: http://badc.nerc.ac.uk

Sources of Global cloud condensation nuclei (CCN) and implications for climate - Ken Carslaw, Leeds
The results from this study appear to indicate that there is no particular  difference between the pre industrial period and present times in regard to sources of CCMs. Nucleation happens as much from natural forces as from industrial effects. The work in this paper demonstrated that 40% is from nucleation and is 60% from primary emissions.

Whilst soot indeed causes CCN, in regard to warming effects, the carbon black component is offset by the remaining part of the soot content; thus carbonaceous particles did not appear to cause warming. 

Why is it so hard to understand the causes of climate model bias and what can be done to make progress? A case-study in seamless prediction - Tim Palmer, (European Centre for Medium-range Weather Forecasts (ECMWF)), Oxford
This presentation looked at the current problems with and causes of uncertainty in predictions of climate models and diagnosing the cause of climate model bias.

Conclusions:

• One way forward is to focus on short-range NWP tendencies, to discover causes of uncertainty and model bias.

• Ensemble data assimilation is seen as an important new methodology.

• In the presentation conclusions it was stated that results confirmed the importance of developing fully seamless weather/climate prediction systems.

Conference closure
The conference closed at 14.30, Wednesday 7 July 2010.