Co-ordinated Airborne Studies in the Tropics - CAST

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences


The unique research capability of the Global Hawk, with ultra-long flights possible in the upper troposphere and lower stratosphere, provides a major new opportunity to advance atmospheric science. In response to the NERC/STFC/NASA collaborative initiative, we have assembled an experienced UK team that proposes to execute a research programme covering fundamental science and technology development, which, by working with the Global Hawk, will radically enhance our future research capabilities.

The Tropical Tropopause Layer (TTL) is a crucial region for chemistry/climate interactions. Building on work we have already done in this area , we will collaborate with NASA's ATTREX programme to study the TTL over the Pacific Ocean and South East Asia, with new measurements and analysis. We will address fundamental questions related to atmospheric composition, radiation and transport. The TTL controls the transport of water vapour, the crucial radiative gas, into the stratosphere; we will advance understanding of the role of sub-visible cirrus in water vapour processes. The TTL is also the main route by which very short-lived halogen species, which represent a large uncertainty in future stratospheric ozone evolution, enter the stratosphere. We will improve knowledge of the budgets of these gases and of their chemical transformation and transport through the TTL, including the role of convective transport into the TTL and the subsequent routes for transport from the TTL to the lower stratosphere. Improving representation of these processes in global chemistry/climate models is a key aim.

In order to study these processes, The FAAM BAe-146 will be deployed in Guam in Jan/Feb 2014. It will fly coordinated flights with the Global Hawk which will making measurements in the same period in the TTL over the West Pacific. Detailed involvement in all phases of the collaborative missions with ATTREX will enhance the UK potential for future research using the Global Hawk, including advanced capability in mission planning and methodologies for complex, real-time data analysis. The aircraft measurements will be interpreted in conjunction with ground-based and balloon-based measurements of very short-lived halogen species and ozone, using a complementary group of regional high resolution models, global composition models and a global cirrus model.

We will develop and test two new instruments and new software for the payload/mission-scientist interface, which are ideally suited for the capabilities of the Global Hawk. One new instrument will allow quantification in the TTL of the important physical properties of sub- and super-micron sized particles, allowing new information about clouds and radiation. We will develop a new short-wave IR spectrometer to measure greenhouse (CO2, CH4, and H2O) and other (CO) gases in the lower atmosphere by remote sensing, taking advantage of the very long flights in the upper troposphere and lower stratosphere. Both instruments will be flight-tested in CAST.

Planned Impact

Policy makers, atmospheric scientists and the general public makers will be among the long term beneficiaries of this research. The work relates to two major policy questions; the control of halogenated substances, regulated under the Montreal Protocol, and climate change, the topic of the Kyoto Protocol. Our science will inform the international assessment processes and will be of direct interest to government departments, chiefly DECC and DEFRA.

The general public has a keen interest in global change, in general, and ozone depletion, in particular. It remains extremely important to engage with the public, to provide latest scientific evidence related to these issues, to counter the increasing levels of misinformation being propagated. We will engage with these various groups in a number if ways: through formal and informal meetings, through the peer-reviewed literature and through our web pages. Nearly all PIs give popular lectures on environmental change issues at e.g. schools and will continue to do so. We also often speak to the media.

There is a large number of people in science, the private sector and government who are interested in understanding the capabilities that can be developed for atmospheric observation from UAVs as well as what the potential uses are. CAST will inform and engage with this community in order to share the experience from CAST and to learn from the experience of others. This has the potential to develop a real UK presence in the field of UAV use and research.

CAST will provide career development for PhD students and PDRAs through involving them in the planning and implementation of field campaigns and presentations of results at project meetings, international conferences and in the peer-reviewed literature. In addition all people involved in CAST will learn about the planning and uses for UAVs.


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Harris N (2017) Coordinated Airborne Studies in the Tropics (CAST) in Bulletin of the American Meteorological Society

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Newton R (2018) Observations of ozone-poor air in the tropical tropopause layer in Atmospheric Chemistry and Physics

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Newton R (2016) Ozonesonde profiles from the West Pacific Warm Pool: measurements and validation in Atmospheric Chemistry and Physics

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Newton R (2017) Observations of ozone-poor air in the Tropical Tropopause Layer in Atmospheric Chemistry and Physics Discussions

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Pan LL (2017) The Convective Transport of Active Species in the Tropics (CONTRAST) Experiment. in Bulletin of the American Meteorological Society

Description New insights into oxidation chemistry in the Pacific tropical warm pool will allow us to challenge global chemistry models.

New insights into the structure of high altitude cirrus and their potential radiative properties.

The review paper for the CAST project has now been published, Harris et al. (2017). The overall summary of the project results is provided below:
The main field activities of the Coordinated Airborne Studies in the Tropics (CAST) campaign took place in the west Pacific during January-February 2014. The field campaign was based in Guam (13.5°N, 144.8°E), using the U.K. Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 atmospheric research aircraft, and was coordinated with the Airborne Tropical Tropopause Experiment (ATTREX) project with an unmanned Global Hawk and the Convective Transport of Active Species in the Tropics (CONTRAST) campaign with a Gulfstream V aircraft. Together, the three aircraft were able to make detailed measurements of atmospheric structure and composition from the ocean surface to 20 km. These measurements are providing new information about the processes influencing halogen and ozone levels in the tropical west Pacific, as well as the importance of trace-gas transport in convection for the upper troposphere and stratosphere. The FAAM aircraft made a total of 25 flights in the region between 1°S and 14°N and 130° and 155°E. It was used to sample at altitudes below 8 km, with much of the time spent in the marine boundary layer. It measured a range of chemical species and sampled extensively within the region of main inflow into the strong west Pacific convection. The CAST team also made ground-based measurements of a number of species (including daily ozonesondes) at the Atmospheric Radiation Measurement Program site on Manus Island, Papua New Guinea (2.1°S, 147.4°E). This article presents an overview of the CAST project, focusing on the design and operation of the west Pacific experiment. It additionally discusses some new developments in CAST, including flights of new instruments on board the Global Hawk in February-March 2015.

N. R. P. Harris
Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
L. J. Carpenter
Department of Chemistry, Wolfson Atmospheric Chemistry Laboratories, University of York, York, United Kingdom
J. D. Lee and G. Vaughan
National Centre for Atmospheric Science, York, United Kingdom
M. T. Filus, R. L. Jones, and B. OuYang
Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
J. A. Pyle
Department of Chemistry, University of Cambridge, and National Centre for Atmospheric Science, Cambridge, United Kingdom
A. D. Robinson
Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
S. J. Andrews
Department of Chemistry, Wolfson Atmospheric Chemistry Laboratories, University of York, York, United Kingdom
A. C. Lewis
Department of Chemistry, Wolfson Atmospheric Chemistry Laboratories, University of York, York, United Kingdom, and National Centre for Atmospheric Science, York, United Kingdom
J. Minaeian and A. Vaughan
Department of Chemistry, Wolfson Atmospheric Chemistry Laboratories, University of York, York, United Kingdom
J. R. Dorsey
National Centre for Atmospheric Science, and School of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, United Kingdom
M. W. Gallagher, M. Le Breton, R. Newton, and C. J. Percival
School of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, United Kingdom
H. M. A. Ricketts
National Centre for Atmospheric Science, York, United Kingdom
S. J.-B. Bauguitte, G. J. Nott, and A. Wellpott
Facility for Airborne Atmospheric Measurements, Cranfield, United Kingdom
M. J. Ashfold
School of Biosciences, Malaysia Campus, University of Nottingham, Semenyih, Malaysia
J. Flemming
European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
R. Butler and P. I. Palmer
School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
P. H. Kaye and C. Stopford
Centre for Atmospheric and Instrumentation Research, University of Hertfordshire, Hatfield, United Kingdom
C. Chemel
Centre for Atmospheric and Instrumentation Research, University of Hertfordshire, and National Centre for Atmospheric Science, University of Hertfordshire, Hatfield, United Kingdom
H. Boesch
Earth Observation Science, Department of Physics and Astronomy, and National Centre for Earth Observation, University of Leicester, United Kingdom
N. Humpage
Earth Observation Science, Department of Physics and Astronomy, University of Leicester, United Kingdom
A. Vick
U.K. Astronomy Technology Centre, Edinburgh, United Kingdom
A. R. MacKenzie
Birmingham Institute of Forest Research, University of Birmingham, Birmingham, United Kingdom
R. Hyde and P. Angelov
Data Science Group, Lancaster University, Lancaster, United Kingdom
E. Meneguz and A. J. Manning
Met Office, Exeter, United Kingdom
Exploitation Route Project is ongoing -
Technology development on Global hawk is being re-tasked for FAAM UK research aircraft
Final ice chamber experiments using the new small ice-depolarisation spectrometer have been completed by CAIR Hertfordshire using the Manchester facility. Data is currently being analysed. Results were used to support an application to NERC by CAIR, Ulanowski, Z. (2016) to investigate the novel new findings in CAST of spheroidal particles in high altitude cirrus. This was also reported in the Manchester work with the ESR Cloudy CENR chamber consortium and was subsequently published in 2016.
Sectors Aerospace, Defence and Marine,Electronics,Environment

Description Project is ongoing - multiple workshops are using the data from CAST-1 to test atmospheric chemical models to improve our understanding of the remote marine atmosphere. Coordination of international multi-disciplinary teams has enabled networking for PhD stduents and to imporve the profile of UK scientists in this field internationally. The full data sets from the CAST field project from Manus Island have now been made available and is available on CEDA for general use.
First Year Of Impact 2016
Sector Environment
Impact Types Societal

Description NERC Standard Grant
Amount £11,000 (GBP)
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 10/2017 
End 09/2020
Title EUFAR ICCP Cloud Expert Workshop 
Description The EUFAR ICCP Workshop on Data Processing, Analysis and Presentation Software of Cloud Probes took place at the University of Manchester from 23 to 24 July 2016. More than 60 cloud measurement experts and students from Europe, America, Asia and Australia participated in the workshop with the objectives to summarise current data processing algorithms for measurements made with cloud spectrometers operated on research aircraft, to discuss differences in the data processing methods, to assess optimum practices and to recommend a way forward in improving data quality from cloud probes. After a welcome and introduction to the workshop by Darrel Baumgardner (Droplet Measurement Technologies), Christiane Voigt (leader of EUFAR's expert working group on In Situ Characterisation of Cloud and Precipitation Particles) presented an overview of EUFAR activities. Colin Gurganas (SPEC) showed a new study that addressed the oversizing of out-of-focus particles by the 2D-S. The session continued with a discussion of open issues related to cloud data processing. Darrel Baumgardner presented a summary of results from a questionnaire on data processing issues that had been responded to by 15 participants. The summary included current practices on data corrections for airspeed, out of focus particles, shattering and ice crystal size/habit definition. Greg McFarquhar (University of Illinois) showed a study that underscored the uncertainties in deriving particle size distributions, using the same data set from optical array probes (OAP) but processed by three separate groups. Although the same algorithms were supposed to be implemented in the processing, there were significant differences that still remained due to different criteria for accepting particles. The next session introduced eight different software packages to process and display measurements from cloud probes. These were developed and are maintained by the University of North Dakota (David Delene), University of Manchester (Jonathan Crosier), University of Illinois (Greg McFarquhar/Wu Wei), NCAR (Aaron Bansemer), previous standards & protocols engineer under EUFAR 2008-2013 (Matt Freer), SPEC (Colin Gurganas) and Environment Canada (Alexei Korolev). The day ended with an introduction and a tutorial to Python by Nick Guy and Matt Freer. A discussion on the way forward in cloud data analysis was opened on day two. This included a dialogue on definitions of microphysical cloud parameters and corrections to be applied to cloud data analysis. The urgent need for a common international reference library that includes the individual processing algorithms was agreed upon by the 43 participants in attendance. The reference database should be a living document with a quality control by referencing to existing literature or by an internal review process and an easy follow up of track changes. The possibility to assign a DOI for individual processing algorithms was emphasised. Simulated or experimentally derived data sets can serve as reference cases to test, evaluate or compare the processing algorisms. EUFAR, who currently maintains EGADS (EUFAR Airborne Data-processing Software), was recommended as a possible first choice to host such a database. In addition, an intercomparison paper on cloud data processing algorithms is planned as one outcome of the workshop. These actions will be initiated by Darrel Baumgardner, David Delene and the international cloud community possibly in connection to the EUFAR expert working group on cloud instrumentation. The progress can be followed in workshops linked to the ICARE2 international conference on aviation research hosted by EUFAR in 2017 and the AMS/ICCP conferences in 2018 and 2020. In summary, the workshop offered a unique opportunity to bring together leading experts and young scientists to exchange information in the challenging and fast evolving field of airborne cloud measurements. The action items that were identified in this workshop and that will be carried out in the near future will be an important step forward in the interaction within and outside of the cloud physics community to improve the quality and fidelity of cloud measurements. 
Type Of Material Improvements to research infrastructure 
Year Produced 2016 
Provided To Others? Yes  
Impact Collaboration between Manchester Centre for Atmospheric Science, NCAS and NCAR-USA have resulted in improved data quality control protocols for cloud microphysical data products delivered by the NERC FAAM aircraft faiclity. This has been achieved in the UK through software tools (OASIS - Dr. J. Crosier) delivered by Manchester and is not comemrcialised by one of the leading cloud instrument manufacturers, DMT, USA. 
Description Global Hawk Integration Study 
Organisation National Aeronautics and Space Administration (NASA)
Department NASA Dryden Flight Research Centre
Country United States 
Sector Public 
PI Contribution An integration workshop was held at NASA Dryden Flight Research Colorado between NASA Payload Specialist staff (Dr. D. Fratello, lead manager), Grumman technical design staff, University of hertfordshire Design engineers and Manchester University aerosol & cloud research staff. Input from ATTREX Global Hawk users and third party instrument design specialists (SPEC Inc. Dr. P. Lawson) was also provided. The successful outcome of this meeting was an agreed design specification for a unique UK in situ particle spectrometer to be installed on the Global Hawk for future UK UTLS research activity.
Start Year 2012
Description Cloud Microphysics Data Analysis Workshop - ICCP 2016 Manchester 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact This workshop, hosted and funded by the International Conference on Clouds & precipitation and EUFAR was an Expert Workshop on Data Processing, Analysis & Presentation of Software of Cloud Probes.
The International Commission on Clouds and Precipitation (ICCP) together with the EUFAR Expert Working Group dedicated to In Situ Characterisation of Cloud and Precipitation Particles are organising a 2-day workshop on data processing, analysis and presentation of software of cloud probes, prior to the 17th International Conference on Clouds & Precipitation.
The workshop took place in Manchester from 23 to 24 July 2016. Click here to see the workshop agenda.
The previous 2014 workshop on analysis of cloud measurements confirmed that there is a serious lack of consistency in not only what correction/analysis algorithms are applied to cloud measurements but also in how they are implemented. An informal poll at the close of the meeting indicated that the majority of the participants were supportive of action to bring consensus, when possible, to issues related to "best practices" when processing data and reporting results. This is the motivation for this workshop.

The particular objectives of the 2016 meeting were as follows:
1. Identify those processing algorithms that are critical for producing results with the
lowest uncertainties.
2. Reach consensus on optimum practices for as many of these algorithms as possible, including all aspects of their implementation and documentation.
3. Identify aspects of algorithms that cannot be optimised in general and that must be set for individual probes or individual datasets

4. Organise a working group (similar to or possibly complementary to the EUFAR EWG group) that will oversee the development and maintenance of a data base of processing algorithms and, if supported by community consensus, direct the development of a common data processing and analysis package that will incorporate all the algorithms identified in objective (1)


The outcomes of the meeting were:

A document describing approved processing algorithms by the consensus of participants at the meeting and via a questionnaire sent to the cloud physics community at large.
A new working group whose responsibilities will be clearly defined. Some members will be drawn from participants at the workshop while others may come from the cloud physics community at large.
A new data processing and analysis system will be defined with an outline of its future structure and implementation based on discussion of this document.
Research students were engaged at the highest level with respect to approved data analysis techniques and approaches for their cloud microphysics research relevant to their approved practice for inclusion in PhD theses and their publications.
Year(s) Of Engagement Activity 2016