"To what extent was the Little Ice Age a result of a change in the thermohaline circulation?" project. This was a Natural Environment Research Council (NERC) RAPID Climate Change Research Programme project (Joint International Round - NE/C509507/1 - Duration 1 Aug 2005 - 31 Jul 2008) led by Dr Tim Osborn of the University of East Anglia, with co-investigators at the University of East Anglia and Royal Netherlands Meteorology Institute. The dataset collection contains various model experiment output used in an analysis of whether the Little Ice Age climate could have been generated by one or more of the following factors: a weakening of the Atlantic thermohaline circulation; the persistence of a generally negative North Atlantic Oscillation; or reduced radiative forcing (by increased volcanic activity, reduced solar insolation and lower greenhouse gas concentrations relative to the present). Rapid Climate Change (RAPID) was a £20 million, six-year (2001-2007) programme for the Natural Environment Research Council. The programme aimed to improve the ability to quantify the probability and magnitude of future rapid change in climate, with a main (but not exclusive) focus on the role of the Atlantic Ocean's Thermohaline Circulation.

The CRYOspheric STudies of Atmospheric Trends in stratospherically and radiatively important gases (CRYOSTAT) will undertake the first combined measurements of virtually all significant Greenhouse gases (GHGs)(other than water vapour), ozone-depleting substances (ODSs), and related trace gases in contiguous firn and ice profiles, spanning as much as 200 years, from both the northern and southern polar ice caps. The dataset contains concentrations of isotopes (CH4, N20, CO, CO2, N20, SF6, CH3Br, halocarbons, and hydrocarbons) in firn, N2O concentrations in ice, ice core density, firn diffusivity, and weather measurements. CRYOSTAT is an evolution of the FIRETRACC/100 project, the data from which is also held at BADC.

"The Circulation, overflow, and deep convection studies in the Nordic Seas using tracers and models" project was a Natural Environment Research Council (NERC) RAPID Climate Change Research Programme project (Round 1 - NER/T/S/2002/00446 - Duration 1 Aug 2003 - 31 Oct 2006 ) led by Prof Andrew Watson of the University of East Anglia, also with co-investigators at the University of East Anglia. Dataset contains sources of water in the Greenland-Scotland overflows: recent tracer release and transient tracer observations, as well as the initiation of convection and its relation to submesoscale hydrodynamics. This dataset collection contains MIT General Circulation Model (MITgcm) ocean model basin and channel experiment outputs. The project investigated two aspects of the Nordic Seas circulation of importance to the North Atlantic meridional overturning circulation (MOC): (1) Sources of water in the Greenland-Scotland overflows: recent tracer release and transient tracer observations were used to constrain inverse models of the sources of Denmark Straits and Faroe-Bank channel overflow waters. (2) The initiation of convection and its relation to submesoscale hydrodynamics: very high-resolution non-hydrostatic models for the Central Greenland Sea were used to model recent observations, which show convection to be intimately related to local sub-mesoscale structure.: The objective was to develop improved descriptions of convection for use in OGCMs, to more accurately describe how the sinking branch of the MOC will be affected by changes in forcing. Rapid Climate Change (RAPID) was a £20 million, six-year (2001-2007) programme for the Natural Environment Research Council. The programme aimed to improve the ability to quantify the probability and magnitude of future rapid change in climate, with a main (but not exclusive) focus on the role of the Atlantic Ocean's Thermohaline Circulation.

The Atmospheric Chemistry Studies in the Oceanic Environment (ACSOE) OXIdising Capacity of the Ocean Atmosphere (OXICOA) Free Tropospheric Experiment (FREETEX) Gas and Aerosol Data from Jungfraujoch High Alpine Research Station contains measurements of chemical species implicated in the control of ozone (O3, NOx, NOy, HNO3, PAN, CO, HO2 + RO2, HCHO, VOCs, etc.), at the Jungfraujoch High Alpine Research Station (3,580m above sea level) over a five-week period in 1996 and again in 1998. Jungfraujoch is located in the lower free troposphere during winter and very often in spring and autumn, during which ozone concentration increases, making it an ideal location to study ozone and peroxy radical chemistry observed in the free troposphere.

This is a copy of The Berlin Stratospheric Data Series provided to the BADC by K. Labitzke and her collaborators (2002) as a CD from the Meteorological Institute, Free University Berlin. This data set contains temperature and geopotential height data on the 100, 50, 30, 10 mb pressure surfaces produced at the Meteorological Institute, Free University of Berlin, from radiosonde data and rocket observations. This data series also contains summer, winter and annual trends and variability of the data, climatological monthly mean temperature and geopotential height at 30 mb, and intercomparisons with other data series. There are also sections on the quasi-biennial oscillation (QBO) and the global signal of the 11-year sunspot cycle in the stratosphere.

Quaternary QUEST was led by Dr Tim Lenton at UEA, with a team of 10 co-investigators at the Universities of Cambridge, Oxford, Reading, Leeds, Bristol, Southampton and at UEA. This dataset collection contains glacial and isotope model data. Over the last million years, the Earth has experienced a sequence of temperature oscillations between glacial and interglacial states, linked to variations in the Earth’s orbit around the sun. These climate oscillations were accompanied by changes in atmospheric CO2, but the fundamental reasons for this relationship are still unresolved. This project team aimed to compile a synthesis of palaeodata from sediments and ice cores, improve the synchronization of these records with each other, and use this greater understanding of the Earth’s ancient atmosphere to improve Earth system models simulating climate over very long timescales. A combined long-term data synthesis and modelling approach has helped to constrain some key mechanisms responsible for glacial-interglacial CO2 change, and Quaternary QUEST narrowed the field of ocean processes that could have caused glacial CO2 drawdown.

Anthropogenic influence on Upper Tropospher-Lower Stratosphere (UTLS) clouds and aerosol (CIRRUS) UTLS round 5 project led by Prof. Tom Choularton. The dataset contains the total number of Condensation Nuclei (CN), CCN, IN and the size distribution of optically active particles in clean and polluted air in the UTLS region over the UK, the number, size distribution, phase and morphology of droplets and crystals in cirrus cloud. Objectives -To measure the total number of Condensation Nuclei (CN), CCN, IN and the size distribution of optically active particles in clean and polluted air in the UTLS region over the UK. Assessment of their spatial distribution and their likely source based on tracer measurements and air mass history. -To use a unique suite of state of the art instruments to quantify the extent to which air mass history, and gas and particle loading can affect the microphysical properties of cirrus clouds in the UTLS region, in particular, the size distribution, phase and morphology of cloud particles. -To obtain estimates of HNO3 loss to cirrus clouds and the subsequent effect on the aerosol population after the cloud has evaporated using case studies involving one or more wave clouds. -To make observations of the number, size distribution, phase and morphology of droplets and crystals in cirrus cloud and the number and size distribution of interstitial particles and correlate these with measurements of tracers that identify anthropogenic anthropogenic influence. Hence building on objective 3 to investigate the influence of cirrus on the distribution of aerosol and gases in the UTLS region as cloud and precipitation evaporate. -To make an assessment of the chemical composition of the particulate in the UTLS region as a function of their size, their spatial variability and the effect different sources have on their composition. -To use measurements of the masses of key components as a function of size of cirrus particle dry residues and interstitial particles to determine if there are distinct chemical differences between activated and unactivated particles. -To establish the partitioning of oxidised nitrogen between the gas and aerosol phases as a function of air mass history and source region. Methodology These studies were performed during the spring/summer of 2005 over the UK using the BAE 146 aircraft for in situ sampling Experiments were undertaken in a wide range of meteorological conditions i.e. in frontal cirrus, in convective conditions and in anticyclonic conditions. The aircraft made measurements below and within the cirrus cloud.

Aircraft Measurement of Chemical Processing and Export fluxes of Pollutants over the UK (AMPEP) was part of the NERC Polluted Troposphere Research Programme project (Round 1 - NER/T/S/2002/00152 - Duration 2002 - 2005) and was led by Prof. D Fowler, NERC Centre for Ecology and Hydrology. This project was focussed on direct measurement of the atmospheric mass budget of a range of pollutants in the gas and aerosol phase in the boundary layer over the UK. New, state of the art equipment was applied to measure the atmospheric mass budget and, in particular, the net export from the downwind coast over the UK. For the majority of the pollutants this is the dominant term and its measurement provides a very powerful test of current understanding of the processes and the current generation of long range transport models. The approach was applied to sulphur compounds, oxidized and reduced nitrogen, ozone and related photochemical oxidant precursors, mercury, a range of heavy metals and the main radiatively active gases. The analysis and interpretation of the data was completed using a range of current long range transport, transformation and deposition models. AMPEP was an aircraft measurement campaign using the FAAM BAe-146-301 and the flights were scheduled to take place between March and September 2005. Flights took place between 21 Apr 2005 and 19 September 2006. The datasets include data from: - the core FAAM instruments. - non-core instruments fitted for the campaign including the UMIST aerosol mass spectrometer, gas analysers, aerosol filters, particle counters and a tunable diode laser, which measured a broad range of atmospheric trace species and aerosols.

The SAM II instrument, aboard the Earth-orbiting Nimbus 7 spacecraft, was designed to measure solar irradiance attenuated by aerosol particles in the Arctic and Antarctic stratosphere. The scientific objective of the SAM II experiment was to develop a stratospheric aerosol database for the polar regions by measuring and mapping vertical profiles of the atmospheric extinction due to aerosols. This database allows for studies of aerosol changes due to seasonal and short-term meteorological variations, atmospheric chemistry, cloud microphysics, and volcanic activity and other perturbations. The results obtained are useful in a number of applications, particularly the evaluation of any potential climatic effect caused by stratospheric aerosols. This dataset collection contains 14 years of polar Arctic and Antarctic aerosol extinction profiles, atmospheric temperature and pressure data obtained from the Stratospheric Aerosol Instrument II (SAM II) on the NIMBUS 7 satellite.

HiGEM (High Resolution Global Environmental Modelling) is a UK programme in between NERC (Natural Environment Research Council) and the Hadley Centre of the Met Office. The aim is to advance in the fidelity of simulations of the global environment by taking the new Met Office climate model (HadGEM1a) to unprecedented resolutions. The resulting simulations aim to improve our understanding of mechanisms of climate variability and change on timescales of days to centuries.