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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Description This consortium project has seen the development of advanced instruments for trace gas analysis and wing-mounted probes able to be to be carried on the NASA Global Hawk atmospheric research aircraft (and subsequently for other UK research aircraft). The cloud instrument, AIITS (Aerosol Ice Interface Transition Spectrometer) developed between the University of herts and University of Manchester is now capable of providing detailed information about the size, shape, phase and concentration of atmospheric particles, such as ice crystals, droplets, mineral particles, and biological particles such as pollens or spores down to micrometre sizes.Measured profiles of aerosols and various trace gases including very short lived halocarbons (VSLS) by the University of York from the sea-surface up to 8km by the FAAM aircraft. Such information is critical to improving understanding of cloud radiative properties, the largest source of uncertainty in climate modelling (IPCC) particularly.

As part of the CAST project measurements were provided by the FAAM research aircraft as well as ozone-sonde measurements in the data sparse region of the Pacific, based in Guam. CAST UK partners coordinated the FAAM aircraft measurements alongside measurements with the US Global Hawk measurements on which UK instruments were also deployed. University of Edinburgh, Hertfordshire, York and Cambridge were deployed at the Armstrong Global Hawk base to assist with coordination fo the Global Hawk flights and measurements.
The FAAM BAe-146 aircraft measurement flights from Guam in 2014 were coordinated flights with the Global Hawk which made similar measurements in the Tropical Tropopause Layer over the West Pacific as part of the US ATTREX project. Integration of UK scientists in international joint aircraft projects enhances aUK potential for future research using a variety of new research aircraft. The continued development of real-time instrumentation and software tools has been fostered and provides the Uk with advanced capability in mission planning and methodologies for complex atmospheric projects. The aircraft measurements during ATTREX were used to place ground-based and balloon-based measurements of ozone (NCAS/Manchester) and short-lived halogen species (University of York). These data were made available for assimilation by a complementary group of regional high resolution models, global composition models and a global cirrus model using the Global Hawk database.
These data were key in collaboration with US groups and provided UK-US science communities with key intercalibration trace gas and aerosol data sets . Contribution to knowledge of VSLS impacts on the lower stratosphere, and the exchange with the stratosphere in terms of aerosols and trace gases which influence enhanced ozone loss were provided for validation of high resolution chemistry/climate models. Several publications arising and in preparation.
Exploitation Route 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 UK development of airborne scientific instrumentation will support NERC FAAM research aircraft capability development for many future projects/applications.
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 Airborne Holographic Imaging Probe
Amount £106,020 (GBP)
Funding ID NE/T009144/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 09/2019 
End 03/2020
Description CLouds and Aerosol Radiative Impacts and Forcing: Year 2016 (CLARIFY-2016)
Amount £605,765 (GBP)
Funding ID NE/L013584/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2016 
End 12/2020
Description Characterisation and Modelling of Climatically Relevant Primary Biogenic Ice Nuclei in the BEACHON Southern Rocky Mountain Project
Amount £244,499 (GBP)
Funding ID NE/H019049/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 03/2011 
End 09/2013
Description Demonstration of an Aircraft System for Real-Time Discrimination & Reporting of Dust, Volcanic Ash, Ice and Super-cooled Water Particles.
Amount £142,070 (GBP)
Funding ID NE/I023058/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 10/2011 
End 08/2014
Description EUREC4A-UK: Elucidating the role of cloud-circulation coupling in climate
Amount £797,842 (GBP)
Funding ID NE/S015752/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 11/2019 
End 10/2022
Description Greenhouse gAs Uk and Global Emissions (GAUGE)
Amount £333,169 (GBP)
Funding ID NE/K00221X/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2013 
End 01/2017
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