The UTLS-Ozone THESEO (Third European Stratospheric Experiment on Ozone) project was joint activity between the Centre of Atmospheric Sciences at the University of Cambridge and the National Physical Laboratory. THESEO's overall scientific objective were to contribute to the understanding of middle latitude ozone loss by making measurements of a number of important tracers of atmospheric motion and photochemistry, and by interpreting these measurements with state-of-the-art models of atmospheric chemistry and transport. The particular aim of the proposal was to extend THESEO measurements of tracer and chemically active gases both spatially and temporally to provide more comprehensive coverage in the middle latitude low stratosphere and upper troposphere. The measurements were complement the similar EU funded measurements whose focus were primarily high and mid-latitudes in 1998/99. They were part of THESEO 2000 which was an extension of THESEO and which formed the basis of European collaboration with US SOLVE experiment which is studying Arctic ozone loss in the 1999/2000 winter. Together, these measurements provide a unique data set for the study of chemistry and transport processes at mid latitudes. They studied annual transport through the middle latitude lower stratosphere and the processes of mixing with tropical and polar air. Data were interpreted using 3D chemical transport models already developed at Cambridge. The large amount of data collected in polar middle and tropical latitudes during THESEO provided a unique opportunity for the new mid-latitude data to contribute to the understanding of middle latitude ozone decline and, in particular, to understanding the relative importance of in situ ozone loss and transport from other regions. Balloon flights were made from Esrange Kiruna station during the 1999/2000 winter, with balloon payloads incorporating the same UK and European instruments deployed during THESEO.

The African Easterly Jet (AEJ) is part of a climatic system which is of critical importance to African and global weather and climate, but is poorly observed and not well represented in model analyses. For the JET2000 project the Met Office Met Research flight (MRF) aircraft performed four flights, involving transects along and across the jet and the baroclinic zone, to make observations of unprecedented resolution for this part of the world. 110 dropsondes were dropped along the fight path. The Objectives were: 1. African Easterly Jet: To provide detailed synoptic observations of the basic state over mainland West Africa. This will focus on the AEJ and its associated temperature, humidity and PV contrasts. 2. African Easterly Waves: To provide detailed synoptic observations of the AEWs over mainland tropical West Africa. 3. Operational analyses and Forecasts: To assess the impact on operational analyses and forecasts of having extra observations over mainland West Africa for the period of the experiment. The data includes detailed synoptic observations of the basic state over mainland West Africa, and detailed synoptic observations of the African Easterly Waves (AEW) over mainland tropical West Africa.

The 'Measurement of H2O Absorption Cross-Sections for the Exploitation of GOME’ project is a European Space Agency (ESA) funded study. The GOME and SCIAMACHY instruments are downward-viewing satellite-borne spectrometers that observe back-scattered solar radiation from the Earth's atmosphere. Global data on the distributions and vertical profiles of a large number of chemical species present in the atmosphere can be determined from the observations. Ozone distributions are a key measurement, but many other atmospheric gases and vapours involved in ozone chemistry and global climate change are also measured. Water vapour is of particular significance because it dominates the energy balance of the atmosphere. Also the spectrum of water vapour must be adequately understood and accounted for when deriving the concentration or distribution of trace atmospheric species. The dataset contains distributions and vertical profiles of atmospheric chemical species (in particular ozone) as well as the distribution of trace atmospheric species. This dataset is public.

The fully Global Mean Sea-Level Pressure (GMSLP) dataset, was developed in collaboration with CSIRO (Scientific and Industrial Research for Australia), Australia and NIWA (National Institute of Water and Atmospheric Research), New Zealand. It is an historical, 5 deg. x 5 deg. gridded monthly dataset covering the period 1871-1994. The Met Office Hadley Centre recently produced the HadSLP1 dataset which replaces the Global Mean Sea Level Pressure (GMSLP) data sets, and is a unique combination of monthly globally-complete fields of land and sea pressure observations a 5 degree latitude-longitude grid from 1871 to 1998.

NERC-UTLS Ozone Thematic Program, 'Night-Time Chemistry of the Upper Troposphere and Lower Stratosphere' project measuring sunrise NO3 and sunset NO2 column densities above Aberystwyth, Mid-Wales.

The Atmospheric Chemistry and Transport of Ozone (ACTO) in the UTLS was a round 2 UTLS (Upper Troposphere and Lower Stratosphere) project led by Stuart Penkett, University of East Anglia. This dataset collection contains airborne atmospheric chemistry data collected by the Met Research Flight (MRF) C-130 Hercules aircraft and atmospheric chemistry output. Data were already collected on the composition and structure of the troposphere as part of OCTA, ACSOE, and TACIA programmes, UTLS-DCFZ and EU-MAXOX during campaigns in the first half of 1999. There was an obvious progression from the objectives of the previous experiments and those of this project. Therefore analysis of the data from these programmes were valuable for the planning of the new measurement campaign, which were collected in the UTLS using the UKMO C-130 during 40 hours flying time, in the spring/summer period of the 2000. Flights were 3-6 hours and did take place in the North Atlantic off northern Britain and were predominantly in the upper troposphere (4 to 11km) with only occasional sorties into the lower stratosphere. Flights were designed to examine the chemical composition and reactivity of different air masses: boundary layer air (marine and (polluted) continental); tropical and subtropical air; upper tropospheric and lower stratospheric air; and polar air. Detailed meteorological and chemical forecast data were obtained from ECMWF, UKMO and NILU. Domain filling trajectory calculations, with forecast wind fields, were used to locate layers and to determine their orientation, whilst the NILU chemical forecast model provided information on the expected chemical composition of the different air masses. To determine the origin, composition and chemical activity of the different air masses found in the UTLS, measurements were made from a large number of tracers, ozone precursors, reactive species and photochemical products.

Meteosat-7 and its predecessors were the first generation of earth observation dedicated geostationary satellites located at 36000 km above the intersection of the Equator and the Greenwich Meridian. Although superseded by MSG-1 (renamed Meteosat-8) in 2005, Meteosat-7 remained as back-up at 0o longitude until 14th June 2006. Meteosat-7 will be moved to 63oE longitude to continue coverage of the Indian Ocean and take over from Meteosat-5. Meteosat-7 was launched by the European Space Agency and operated by Eumetsat. This dataset collection contains visible, water vapour, thermal and infra-red images of the North Atlantic Ocean, Europe and North Africa from the Meteosat geostationary satellite. Images are archived from 11th November 1999 to June 2006. These images are public. Data were collected every half hour in three wavelength channels for visible, infra-red and water vapour images.

The NERC URGENT thematic programme was set up to integrate urban environmental research across the geological, ecological, freshwater and atmospheric sciences. It worked in partnership with city authorities, industry and regulatory bodies. Deliverables from URGENT funded projects, that belong to Soil, Water, Ecology or Air Sciences, are archived at the BADC. There were 13 air science projects within the URGENT Programme. The largest of these is the PUMA (Pollution in Urban Midlands Atmospheres) Consortium, which is the core of a group of five closely interrelated projects forming the PUMA Consortia. Its geographical scope is the West Midlands County (UK) and Birmingham City but its aim is to provide general insights into urban atmospheric problems. The URGENT "Air" data are mainly in situ ground based measurements in urban and suburban areas but also include observations from aircraft, lab measurements and model results. Retrieved variables include atmospheric chemical species and aerosols, photolysis rates and meteorological/radiative parameters. Software, reports and recommendations to urban planners have also been issued. The thematic programme began in 1998 and lasted for 7 years. URGENT - Observation, Modelling And Management Of Urban Air Pollution (PUMA COnsortium - PUMACO) was a NERC Urban Regeneration and the Environment (URGENT) Air project (GST/02/1981 - Duration: 1/01/1998 - 30/09/2001) led by Prof. Roy M. Harrison, University of Birmingham. The objectives of this project were: -To apply a high spatial resolution meso-scale meteorological model to the West Midlands. This was the first of its kind in the UK. -To add a coupled dispersion and atmospheric chemistry model, capable of predicting both primary and secondary air pollutant concentrations at urban background locations across the conurbation with a horizontal resolution of about 2km and a vertical resolution as low as 25m. The model were validated against high quality measurements of primary pollutants such as carbon monoxide, sulphur dioxide and NOX, as well as secondary pollutants including nitrogen dioxide, ozone and secondary inorganic particulate matter. It was compared with an existing model (UAM). -To make measurements of concentrations of a wide range of both long-lived and transient chemical species including hydrocarbons, carbonyl compounds, oxyacids of nitrogen and the free radical species OH, HO2, RO2 and NO3, which play a key role in atmospheric chemistry. -To validate the atmospheric chemical reaction mechanisms within the model in a depth not previously attempted. -To gain insights into the chemical processes controlling the composition of the urban atmosphere at a very fundamental level. -To produce a management model applicable for national and local government to predict the impact on air quality of specific control strategies for a wide range of criteria pollutants and on a range of timescales (minutes to years). This project was seeking to apply and validate a well accepted meso-scale meteorological model (the Colorado State University RAMS model) coupled with a very detailed chemical scheme within a Lagrangian particle dispersion model. A dozen of urban and suburban sites in and around the West Midlands County (UK) were chosen for the project. The principal urban site was Pritchatts Road, Birmingham City. Peripheric sites included Halfpenny Green Airport (West of Birmingham) and Withybrook Equestrian Centre (East of Birmingham). The field campaigns ran from 11 June - 13 July 1999 and 17 January - 17 February 2000. A variety of observation platforms were used. They included two ambulant laboratories (Birmingham and Leeds teams), a pollution monitoring van and a 10 m high tower allowing measurements to be made at a height of 5 or 10 metres. Most observations were made when the platform was stationary but some data were collected while driving (peripheric sites).

These data are held by the BADC for the Natural Environment Research Council (NERC) Molecular Spectroscopy Facility (MSF). MSF provides world-class scientific equipment and support for infrared (IR),visible, and ultraviolet (UV) spectroscopy. The MSF laboratories are used by many UK and international customers in a wide range of research and development programmes. The data are spectra of various atmospheric gases. These data are public. The data held covers the following areas: Water vapour line parameters Molecular oxygen absorption cross-sections Molecular oxygen/nitrogen absorption cross-sections Hydrofluorocarbon (HFC) infrared absorption cross-sections Perfluorocarbon (PFC) infrared absorption cross-sections Computer software

Meteosat-7 and its predecessors were the first generation of earth observation dedicated geostationary satellites located at 36000 km above the intersection of the Equator and the Greenwich Meridian. Although superseded by MSG-1 (renamed Meteosat-8) in 2005, Meteosat-7 remained as back-up at 0o longitude until 14th June 2006. Meteosat-7 will be moved to 63oE longitude to continue coverage of the Indian Ocean and take over from Meteosat-5. Meteosat-7 was launched by the European Space Agency and operated by Eumetsat. This dataset contains visible images from Meteosat Geostationary Satellites First Generation satellites over full disc.