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 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 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 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 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 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 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 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 A753 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 further the various filaments of air that were sampled in flight A752. That is polluted air, having origins in the Mediterranean region; clean marine boundary layer air; ozone-rich, dry upper tropospheric air (from upper tropospheric jet) and also polluted boundary layer air, which has been uplifted from N. America. The region should be very structured having many different characteristics. The filaments of air were expected to be aligned zonally, sloping downwards to the North. The flight was successful in that some of the filaments were found. However, the filaments were not found in the expected area. During a level hold at FL160 (for air traffic) and at the beginning of the first run at FL170 (NOxy calibrations), a dry ozone-rich filament was sampled. Later during the same run, air with moderately high ozone (around 70 ppb), high relative humidity and elevated peroxide was observed. At the subsequent level (FL240) ozone mixing ratios were generally lower (around 45-50 ppb) and the CN count was elevated (2500). However, during the turn at ca. 12:10 on FL240 (SE corner of the flight), another dry, ozone-rich filament was found. A further filament was expected to the North but this was not found. Towards the end of the flight further investigations were made at FL170, in order to try to find the first area of high ozone air (i.e. the air that was sampled during the first NOxy cal run). This air was found but interestingly, the ozone-rich dry air also correlated with high PAN and black carbon. The instruments generally worked well. The FWVS was adjusted in flight and then found to maintain a good correlation with the GE. Neither the CO nor the HCHO were flown due to previously existing faults. There was a problem with the peroxide pump but this was not until the end of the flight. Meteorology The meteorological situation was dominated by high pressure, centred to the north of Scotland. The south of the country was in a more showery regime. However, not much cloud was observed during flight: small cumulus, broken stratocumulus and some cirrus, were observed at times.

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 A756 for the Atmospheric Chemistry and Transport of Ozone in the upper troposphere-lower stratosphere (UTLS) (ACTO) campaign. The flight was located over the North Atlantic. "Stratospheric Studies, with a low tropopause The tropopause was crossed in this experiment in order to study true stratospheric air with the available instrumentation. Ozone mixing ratios of up to 400ppb were measured and the corresponding CO mixing ratios were around 30 ppb. The discrimination between the two NOy channels was quite apparent: indicating a clear presence of HNO3. PAN was just detectable in this air. On descending back below the tropopause, at around 22,000ft, it was noted that the NOy channel, with the Rosemount inlet, was suddenly found to measure more NOy than the other NOy channel. This correlated better with a change in humidity than with the change in temperature. It has been suggested that the change in conditions causes nitrogen compounds (HNO3?) to be 'flushed off' the inlet. Suggestions have been made to change the inlet to the make it identical to the other inlet (backward facing PFA). The instruments generally worked well. There were some problems with the peroxide, as the flows were very poor, at FL270 and above, and the formaldehyde was measuring high values, thought to be due to a leak in the inlet line. The carbon monoxide instrument showed good anti-correlation with the ozone, after the first run at FL250 (when there were problems due to blockages affecting the flow to the optical filter). It was observed that the HORACE reading is high by about 15 ppb relative to the PC reading. Meteorology The situation was dominated by a low pressure system centred over Ireland (centre pressure 1000mb). The associated low tropopause made the situation ideal for studying stratospheric chemistry with the C-130.

DCFZ investigated the role of frontal shear zones in determining upper tropospheric chemical distributions. This dataset contains aircraft measurements of CO, O3, NOx, CCN, MAXOX, thermodynamics, physical liquid water content, pressure, wind and temperature.