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Meteorological Research Unit

Tethered balloon (top left) with turbulence probe (centre) and cloud droplet probe (bottom right) mounted on cable.

Surface and balloon-borne meteorological observations and research are performed to improve parameterizations in the Unified Model.

The Meteorological Research Unit (MRU) is located at Cardington, Bedfordshire. The facility has a wide variety of research grade surface and sub-surface, mast-mounted and balloon-borne instruments. There has been meteorological research and observational work based at Cardington since the 1920s, from early research, through routine BALTHUM observations during the 1940s and balloon borne turbulence research since the 1970s. The site has been operating in its present form since 1998. Research campaigns are conducted both on site and, during field campaigns, at remote locations throughout the UK. Topics studied include boundary layer cloud and fog, stable boundary layers, flow over hills and urban meteorology.

At the Cardington facility we have a comprehensive suite of surface and mast-mounted instrumentation for both in situ and remote sensing the atmosphere. Quantities measured include wind and turbulence, temperature and humidity, radiation, visibility, aerosols, clouds, fog, soil temperature and moisture content. Data are logged continuously and processed data from the site is made available through the British Atmospheric Data Centre (BADC).  The surface site data record stretches back to 1998. Additional on-site activities include instrument development and trials. Recent examples of instrument development include a dewmeter, to measure dew and fog droplet deposition, and a portable weather station, specially adapted for monitoring fog. These are described below in more detail.

Field campaigns are run for durations of between a few weeks up to more than a year and may include deployment at multiple sites. Surface based detachments are similar to our main facility at Cardington and include a mobile radiosonde and Doppler LiDAR facility, which can be deployed rapidly during periods of interest.

Our research is often in collaboration with other institutes, such as the UK university community,FAAM and Atmospheric Measurement Facility.

Key Aims

  • Improve understanding of meteorological processes in the boundary layer, including high impact weather such as fog, visibility and freezing temperatures
  • Direct validation and development of high resolution numerical models, focusing on specific NWP issues
  • Emphasis is on small scale processes relevant to the latest generation of high resolution models

Current Research Projects

  • LANFEX: MRU is currently working on an 18 month long field project in a valley system in the Welsh Borders region. The purpose of this experiment is to study the formation and evolution of fog in a range of valley and hill top sites. Using the terrain as a natural laboratory, it is anticipated that slight differences in conditions at the various sites will affect the formation of fog, and thus the aim is to examine and compare these differing conditions to improve our understanding of the interaction of processes affecting fog. Five comprehensive observational sites, as well as additional smaller fog monitoring stations are deployed in this region. During this campaign, additional observations (IOPs), will be taken using our mobile radiosonde and tethered balloon facilities, during weather conditions of particular interest. Modelling and data analysis will continue for several years. This experiment is in collaboration with the Atmospheric Processes and Parametrizations group and the Universities of Leeds, Manchester, and East Anglia.
  • COPE - the Convective Precipitation Experiment and OPREC: MRU has recently collaborated with UK and US universities, on a three month Convective Precipitation project on Bodmin moor. This project had a number of different components centred around better understanding the development of convective clouds and precipitation. MRU is particularly interested in the effects of orography, which is the changing height of the land surface, on rainfall. Combined with COPE, OPREC involved a series of weather stations with rain gauges being deployed along a 19 mile stretch of hills and valleys for a period of 12 months. Supplementary instruments and radiosondes were also deployed during intense observing periods, when weather of significant interest was expected. While the observing aspect of the project has now been completed, data analysis is still ongoing.
  • Fog studies: Fog and visibility forecasts are extremely important due to the risks associated with poor visibility for travel, particularly for road safety and at airports. MRU has an important role to play in studying how fog and visibility evolve and we work closely with forecasters and modellers to assess and improve Met Office forecasts. Experiments and case studies are conducted and compared with both large eddy simulations and forecast models, with particular emphasis on evolution of stability, turbulence and droplet spectra over the fog's lifetime.
  • Aerosol and visibility studies: Routine aerosol and visibility observations are made at Cardington. These have been used to construct a neural network visibility predictor, which has been shown to improve prediction of visibility at the Cardington site. Further work aims to extend the study to other sites, such as airports, throughout the UK.

Current Development Projects

  • Dewmeter: A dewmeter has been developed to measure dewfall and fog-droplet deposition. This is a portable and easily deployable device to measure total deposition of dew and fog-droplets with good sensitivity. Different natural and artificial grass surfaces can be deployed in the pan, allowing for a variety of experiments to be performed.
  • Fog monitors: In collaboration with the University of Hertfordshire, a fog monitor has been developed which uses a small laser beam to measure the diameter of fog droplets. This will be deployed as part of a fog monitor station, also measuring temperature, humidity, pressure and rainfall, and which is designed to work remotely and does not require mains electricity. These stations are deployed as a part of LANFEX and also in the vicinity of our research station at Cardington.
  • Mobile Radiosonde and LiDAR facility: MRU has converted a van into a mobile radiosonde facility, enabling measurement of atmospheric profiles of temperature, humidity and winds from a wide variety of locations. The van is also fitted with a Doppler LiDAR, enabling measurement of atmospheric turbulence, cloud properties and volcanic ash.

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