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.

The Institute of Meterological and Climate Research Dornier 128 aircraft data were collected at Chilbolton, Hampshire by instruments on the aircraft, between the 22nd of June 2005 and the 14th of July 2005. The dataset includes measurements of wind direction and wind speed, air density, and air temperature. Measurements taken by the Dornier 128 aircraft and stored in this dataset are: static pressure, uncorrected (hPa) barometric altitude (m) radarheight above ground (m) latitude (deg) longitude (deg) true air speed (m/s) velocity over ground (m/s) vertical velocity (m/s) radiation pyranometer top (W/m2) radiation pyranomter bottom (W/m2) radiation pyrgeometer top (W/m2) radiation pyrgeometer bottom (W/m2) air density (kg/m3) fast air temperature (deg Celsius) potential temperature (deg Celsius) filtered mixing ratio (g/kg) mixing ratio Lyman-Alpha (g/kg) wind component west-east (m/s) wind component south-north (m/s) vertical wind component (m/s) wind direction (deg) wind speed (m/s)

The Exploitation of new data sources, data assimilation and ensemble techniques for storm and flood forecasting Project is a NERC Flood Risk for Extreme Events (FREE) Research Programme project (Round 1 - NE/E002137/1 - Duration January 2007 - April 2010) led by Prof AJ Illingworth, University of Reading. This project investigates possible methods of producing ensemble weather forecasts at high-resolution. These ensembles will be used with raingauge and river flow to improve methods of flood forecasting. The dataset includes radiosonde and wind profiles in England and Wales derived using Doppler radar returns from insects. The radial velocity measurements from insects were converted into VAD profiles by fitting a sinusoid to radial velocities at constant range. All measured profiles have been interpolated to the instrument location. This dataset contains temperature and pressure measurements from radiosondes.

The DIAMET project aimed to better the understanding and prediction of mesoscale structures in synoptic-scale storms. Such structures include fronts, rain bands, secondary cyclones, sting jets etc, and are important because much of the extreme weather we experience (e.g. strong winds, heavy rain) comes from such regions. Weather forecasting models are able to capture some of this activity correctly, but there is much still to learn. By a combination of measurements and modelling, mainly using the Met Office Unified Model (UM), the project worked to better understand how mesoscale processes in cyclones give rise to severe weather and how they can be better represented in models and better forecast. This dataset contains minute resolution meteorological measurements by the Met Office Automatic Weather Stations (AWS) during the DIAMET intensive observation campaigns.

The DIAMET project aimed to better the understanding and prediction of mesoscale structures in synoptic-scale storms. Such structures include fronts, rain bands, secondary cyclones, sting jets etc, and are important because much of the extreme weather we experience (e.g. strong winds, heavy rain) comes from such regions. Weather forecasting models are able to capture some of this activity correctly, but there is much still to learn. By a combination of measurements and modelling, mainly using the Met Office Unified Model (UM), the project worked to better understand how mesoscale processes in cyclones give rise to severe weather and how they can be better represented in models and better forecast. This dataset contains meteorological data recorded by radiosondes launched in support of the DIAMET campaign. Data are from the Manchester radiosondes launched at Aberystwyth and from Met Office sondes at Albemarle, Camborne, Castor Bay, Herstmonceux, Lerwick and Lochranza.

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. 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.

The data were collected by the Met Office’s Radiometrics TP/WVP-3000 which was deployed to Linkenholt on 13 June until 21 September 2005. The dataset contains plots of temperature, relative humidity, pressure, and rainfall amount. It was initially configured to view in the zenith direction with very high time resolution (~12 s). All channels also viewed the internal black body target for relative calibration, initially every 5 minutes. However, initially this did not take place between 11 – 13 UTC due to a configuration error, which was corrected on 8 July 2005. Prior to this date, the calibration of data around noon is prone to drift. The radiometer ran continuously in this mode until 20 July 2005, when it was re-configured to alternative between zenith views and internal black body calibration views in a 30 s cycle because of concerns over the drift in calibration over the previous 5 minute calibration period. There was a power outage on 2 August 2005 from 0730 – 0946 UTC when no radiometer data was available.

The Meteorological Research Flight (MRF) was a Met Office facility, which flew a well-instrumented C-130 Hercules aircraft for atmospheric research purposes. This dataset contains airborne atmospheric and chemistry measurements taken on board the Met Office C-130 Hercules aircraft flight A750 for the Atmospheric Chemistry and Transport of Ozone in the upper troposphere-lower stratosphere (UTLS) (ACTO) campaign. The flight was a transit from Boscombe to Prestwick. The main purpose was to reposition the aircraft at Prestwick for the ACTO detachment. The instruments were operated as an additional test. The data was also monitored for evidence of filaments of upper tropospheric / lower stratospheric air that had been forecast on the 3/5/2000. However, the forecast from 4/5/2000 had suggested that the air would have moved too far North. Thus as expected, there was no evidence of very dry, ozone-rich air, during the flight. There were several instrument errors prior to flight and these were not resolved during the flight. The peroxide instrument was not operated. The carbon monoxide was switched on but did not perform sufficiently to give any useful data. The PERCA operator was not happy with the performance of the instrument (low chain length). The PAN GC was operated on one channel only. The ozone instrument worked OK but it was not displayed correctly on HORACE. The instrument operator therefore made investigations towards the end of the flight in order to understand the problem. The remaining chemistry instrumentation (UEA NOxy, MRF NOx box and the UEA formaldehyde, Leeds hydrocarbon GC) all worked well. Meteorology The meteorological situation was dominated by a high pressure system that was centred to the North West of Scotland. A weak warm front was shown on the midnight analysis over the south of England: no rain was forecast on the PGM. Areas of stratocumulus and altocumulus cloud marked the front. No other notable cloud features were found during the flight.

The Meteorological Research Flight (MRF) was a Met Office facility, which flew a well-instrumented C-130 Hercules aircraft for atmospheric research purposes. This dataset contains airborne atmospheric and chemistry measurements taken on board the Met Office C-130 Hercules aircraft flight A751 for the Atmospheric Chemistry and Transport of Ozone in the upper troposphere-lower stratosphere (UTLS) (ACTO) campaign. The flight was a transit from Boscombe to Prestwick. The main purpose was to investigate a filament of air (with UTLS origins), which had been apparent on the PV forecasts from ECMWF (interpretation by John Methven). The flight was very successful. In particular, the filament of air was located with relative ease. The filament was initially traversed during the ascent to the first level run. The filament position was then confirmed from the water vapour image, details of which were sent to the aircraft via satcom. A rectangular flight plan was carried out at FL230, with legs approximately along the axis of the filament, across the filament and along the outside of the filament. A triangular pattern was flown at the subsequent level, with the final leg running at a slight angle across the filament, such that the edge of the filament was crossed slowly. The filament was apparent in many of the measurements: low humidity, low CN, high ozone (up to around 100ppb), higher PCASP aerosol and high NOy. Other features were apparent near the filament region including air parcels having some evidence of more recent pollution (higher NO and NO2). Hence, further investigation will be required to understand the origins of these parcels. A number of flask samples (37) were also collected for subsequent analysis, There were a few instrument errors prior to flight. The CO and the HCHO were both unserviceable and the FWVS was not fitted. It is hoped that some of the other parameters may be used as tropospheric tracers instead of CO (aerosols, Leeds GC hydrocarbons, bottle sample-hydrocarbons (including methane), bottle sample GC-MS analysis and possible bottle sample CO). Meteorology The meteorological situation was dominated by a large ridge of high pressure, stretching from the Azores to Scandinavia. A weak warm front was analysed on the midday Met. Office Chart, oriented from SW to NE, stretching from 50N, 15W to Scandinavia. There was little cloud associated with the front: mainly a line of stratocumulus with some embedded cumulus (the largest having tops at 25,000ft). The main features appeared to be marked by a gradient in humidity, which was apparent on the water vapour satellite image. "

The Meteorological Research Flight (MRF) was a Met Office facility, which flew a well-instrumented C-130 Hercules aircraft for atmospheric research purposes. This dataset contains airborne atmospheric and chemistry measurements taken on board the Met Office C-130 Hercules aircraft flight A752 for the Atmospheric Chemistry and Transport of Ozone in the upper troposphere-lower stratosphere (UTLS) (ACTO) campaign. The flight was located over the Irish sea. The purpose of the flight was to investigate various filaments of air in the upper troposphere. These were to include uplifted, polluted air from Europe; dry ozone-rich air of stratospheric / upper tropospheric origins and high relative humidity air from the marine boundary layer. The different filaments did appear to be found but further post-flight analysis will be required to confirm the origins. Polluted air was noted with higher NOx mixing ratios. A filament of dry ozone-rich air was also found but at a more southerly position than forecast: it was not investigated in detail but flown through on an approximately Northward leg (i.e. an across-filament run). High relative humidity air was observed at the northern end of the flight track, as forecast. This air had ozone mixing ratios, which were lower than those observed on any of the earlier flights (down to a minimum of around 35 ppb), quite consistent with air of clean marine origins. One interesting feature that was observed, between the high-ozone/low relative humidity air and the low ozone/high relative humidity air, was an area of high relative humidity and relatively high ozone (around 65 ppb). This was clearly correlated with a small but notable increase in peroxide and a good peroxy radical signal: i.e. a region indicating notable ozone loss. This was not one of the regions forecast to be of particular interest but nevertheless it may be very interesting.