MICROphysicS of COnvective PrEcipitation (MICROSCOPE)

Lead Research Organisation: University of Leeds
Department Name: School of Earth and Environment

Abstract

This project will improve predictions of severe convective rainfall by addressing the problem of the microphysics
of precipitation in convective clouds. For the first time, study of the microphysics is embedded in a
project that includes the larger-scale dynamics of convective clouds, as part of the COnvective Precipitation
Experiment (COPE). COPE will connect this microphysical study with the system-scale dynamics of severe
convective UK weather events. COPE will also provide a programme of weather-system modelling, which will
bring the microphysical understanding through to the improved prediction of rainfall at the weather-system, or
catchment scale.

Weather forecast models are now run at resolutions of 1.5 km, which has helped to improve the prediction
of the location and timing of convection. However, quantitative precipitation forecasts are still often poor as
highlighted in the Boscastle event (Golding et al., 2005). This is due in part to the lack of knowledge about the
nucleation of ice particles in convective clouds, the warm rain process, and the rates of production of secondary
ice particles and the subsequent growth of precipitation particles. However, high local accumulations were the
result of both intensity (microphysics of precipitation) and duration (organisation of and interaction between cells
along the convergence line) of precipitation. The latter issue and wider-scale problem will be addressed in other
parts of COPE.

There are two key parts to MICROSCOPE. The first concerns a fundamental problem: how do ice particles
form in clouds as a result of ice nuclei (IN), particularly at high temperatures? The second concerns precipitation:
how do precipitation particles form and what are the rates of production and development? MICROSCOPE will
address the challenge of explaining the production of primary ice particles in cumulus clouds, in the following
ways.
* We will make measurements of the properties of the aerosol particles, particularly soils and biological
material, on the ground and in the boundary-layer with the FAAM 146 aircraft.
* Measurements will be made of the evolution of the droplet size distribution, the possible presence of
supercooled raindrops and the formation of the first ice particles with carefully-guided penetrations of the
aircraft that has been equipped with new instruments that can detect and characterise small ice particles
unambiguously (SID, 2DS, CAS-DPOL).
* The dual-polarisation, Doppler radars will provide measurements of the location and time of the first precipitation
echoes, the air motions and the types of particles.

In order to explain the production and development of precipitation, process model and NWP model results
will be compared to observations of the entrainment process, the development of the warm rain process, the
growth of ice particles into precipitation particles by diffusional growth, the freezing of raindrops into graupel
particles, multiplication by secondary production processes, and riming. The comparisons will be achieved by
making multiple penetrations at increasing altitudes measuring the particle size distributions in space and time
as well as the thermodynamics and dynamics of the cloud, and by obtaining information about the particles and
the rate of increase of the reflectivity echo from the dual-polarisation radar.

The final step of MICROSCOPE, that will be led by the Met Office, is to incorporate the new information into
NWP models and to test against the data gathered during the project.

Planned Impact

The research proposed in MICROSCOPE will potentially have a major
benefit to society and business in the UK by improving weather forecasts
of heavy convective rainfall through it's major contribution to COPE.
Lives may be saved in severe events if sufficient warning is given.
Improved forecasts of flash flooding will also provide greater warning
to businesses so they may be able to take action to save loss of stock.
Thus, it is likely that the Insurance Industry will be the biggest
beneficiary.

Flooding caused by heavy convective rain is a serious problem in the UK
and in the rest of the world. Every year there are reports throughout
the world of major flooding with significant damage and even loss of
life. There are many examples in the UK, such as Boscastle in 2004 and
Ottery St Mary, 2008. The Cabinet Office regards flooding as one of the
major risks to public wellbeing. The Pitt Review, written following the
2007 floods in the UK, stressed the need for better analysis and
forecasting of storms and specifically the need to improve forecasting
skill of heavy precipitation events that lead to flooding. The review
led directly to the setting up of the joint Environment Agency / Met
Office National Flood Forecasting Centre which uses rainfall forecast
output from the UM as input to the national Grid-to-Grad hydrological
forecasting model.

NERC recently funded a consortium proposal to investigate the initiation
of convective storms in the UK: the Convective Storm Initiation Project
(CSIP). This project had a significant impact on the ability of the Met
Office to forecast convective precipitation. It did this by providing
the information that allowed the Met Office to have confidence in a
higher-resolution model. However, the project did not address the issue
of the quantity of precipitation. That is the subject of MICROSCOPE.
The observations made in MICROSCOPE will provide much needed data with
which to compare results from the high-resolution Met Office Unified
Model (UM). Incorporation of research results from MICROSCOPE into
development versions of the UM will be made possible through working
with Met Office. In turn, the MO forecasts will feed into models used
by EA and SEPA.

A second group that will benefit from MICROSCOPE within the context of
COPE is the water companies and hydrometeorological consultancies. They
regard precipitation forecasts as an essential element in their business
operations.

A major indirect benefit to society as a whole is likely to come from
improvements made to global climate models that will result from
knowledge gained about the ice processes in clouds as well as the
entrainment process. Convective clouds and their influences, such as
the vertical transport of heat, moisture and momentum, the effects on
latent and radiative heating, and the chemical processes due to
lightning, are particularly difficult to capture in these models.

Weather forecasts are also an essential element in forecasting the onset
and spread of both human and animal diseases. Work is being carried out
with the National Health Protection Agency on the relationship between
thunderstorms and outbreaks of asthma, for example.

Finally, this research offers the opportunity to work with schools on
outreach activities, particularly since thunderstorms are so dramatic
and appealing to children and the public in general.

Publications

10 25 50
 
Description The processes responsible for the formation and development of ice particles. The importance of the warm rain process for heavy precipitation events. The dynamics of the cloud systems forming along convergence lines in the SW of England.
Exploitation Route Improvement of forecasts by better representation of the ice and warm rain process. Realisation of the importance of the warm rain process and the scale of the cells and the dynamics of the cloud systems.
Sectors Environment

 
Title Microscope data 
Description Cloud physics, aerosol and meteorological data gathered by instruments on board the FAAM BAe aircraft; Cloud physics data from the Wyoming King Air aircraft; Data from dual-polarisation Doppler X-band radar; Data from aerosol instruments in ground-based aerosol container; data from Doppler lidar and wind profiler. 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact Work in progress -- no notable impact completed at the moment 
 
Description Collaboration with Professor Lasher-Trapp, University of Illinois 
Organisation University of Illinois at Urbana-Champaign
Country United States 
Sector Academic/University 
PI Contribution The project was my idea and led by me. The field campaign was organised by the UK team. I am providing leadership of the research.
Collaborator Contribution Professor Lasher-Trapp led a proposal to NSF to collaborate in the project and bring the University of Wyoming King Air to the project. She has a graduate student and a post-doctoral scientist working on the project. We talk once per week on GoToMeeting and meet once per year. Papers are in progress led by her.
Impact An excellent dataset from the field campaign.
Start Year 2010
 
Description Drs Dave Leon and Jeff French, University of Wyoming 
Organisation University of Wyoming
Country United States 
Sector Academic/University 
PI Contribution Project led by UK. I am providing leadership in research.
Collaborator Contribution Drs. French and Leon and their team brought the University of Wyoming King Air aircraft to the field campaign. They have graduate students and post-doctoral scientists working on the research.
Impact Excellent dataset from the field campaign
Start Year 2010
 
Description Met Office COPE 
Organisation Meteorological Office UK
Country United Kingdom 
Sector Public 
PI Contribution Radar and other ground-based measurements, operation of instruments on the aircraft, analysis and synthesis of data.
Collaborator Contribution Operation of the FAAM BAe146 aircraft and some instruments on board. Forecasting and model runs. Step between scientific results and possible improved parametrisations.
Impact Discovery of the importance of warm rain in flash-flooding events. The dynamics of the cloud systems along the convergence line that cause the prolonged and heavy rain. The formation and development of ice. These have been published or are in progress.
Start Year 2013
 
Description Educational display and pamphlet 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact A display board and pamphlet was produced to describe the scientific background behind the COPE project, its aims and objectives and the anticipated impact of the research.

Engagement with the public leading to their increased understanding of the scientific challenges and questions being addressed in COPE.
Year(s) Of Engagement Activity 2013
 
Description Flash Flooding workshop with end users 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation workshop facilitator
Geographic Reach National
Primary Audience Industry/Business
Results and Impact The workshop was planned as part of the Impact in this Microscope grant to bring people together that are working on various aspects of flash flooding in the UK from research scientists, businesses, the Natural Hazards Partnership and government bodies. The meeting achieved that goal.

Several emails from the Natural Hazard Partnership wanting to work with us. Collaboration started between different disciplines. Connections with business.
Year(s) Of Engagement Activity 2014
 
Description Public talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Providing information to the public on the important research being undertaking, generating interest in the science challenges and questions being addressed and engaging in discussions.

Further interest in the subject and being asked to give the same presentation to other local groups who hear about it through websites and word of mouth.
Year(s) Of Engagement Activity 2013,2014
 
Description School workshops 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Schools
Results and Impact The workshop activities provide an introduction to meteorological concepts and the scientific questions researchers are addressing in this field.
It also demonstrates to them that there are a large number of career paths in this subject area.


Schools have requested participation in activities at future events.

Teachers have provided feedback that the activity inspires the students, raises awareness of how scientific concepts are applied to the real world, is valuable to their curriculum, consolidates prior learning and increases uptake at GCSE.
Year(s) Of Engagement Activity 2013,2014
 
Description Town hall meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact A presentation on COPE was given to representatives from various local authorities and interest groups, in order to engage them in the project and to enlist their help in the planning and deployment of instruments. The meeting allowed the attendees to ask questions and discuss any concerns.

The meeting generated public interest and an endorsement of the project taking place in their local area. It encouraged them to visit the project sites and learn more about the research being undertaken.
Year(s) Of Engagement Activity 2012