Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories old model data for PUMA.

This dataset comprises monthly mean data from a global, transient simulation with the Whole Atmosphere Community Climate Model eXtension (WACCM-X) from 1950 to 2015. WACCM-X is a global atmosphere model covering altitudes from the surface up to ~500 km, i.e. including the troposphere, stratosphere, mesosphere and thermosphere. WACCM-X version 2.0 (Liu et al., 2018) was used, part of the Community Earth System Model (CESM) release 2.1.0 made available by the US National Center for Atmospheric Research. The model was run in free-running mode with a horizontal resolution of 1.9° latitude 2.5° longitude (giving 96 latitude points and 144 longitude points) and 126 vertical levels. Further description of the model and simulation setup is provided by Cnossen (2020) and references therein. A large number of variables are included on standard monthly mean output files on the model grid, while selected variables are also offered interpolated to a constant height grid or vertically integrated in height (details below). Zonal mean and global mean output files are included as well. The following data file types are included: 1)Monthly mean output on the full grid for the full set of variables; [DFT] = '' 2)Zonal mean monthly mean output for the full set of variables; [DFT] = _zm 3)Global mean monthly mean output for the full set of variables; [DFT] = _gm 4)Height-interpolated/-integrated output on the full grid for selected variables; [DFT] = _ht A cos(latitude) weighting was used when calculating the global means. Data were interpolated to a set of constant heights (61 levels in total) using the Z3GM variable (for variables output on midpoints, with "lev" as the vertical coordinate) or the Z3GMI variable (for variables output on interfaces, with "ilev" as the vertical coordinate) stored on the original output files (type 1 above). Interpolation was done separately for each longitude, latitude and time. Mass density (DEN [g/cm3]) was calculated from the M_dens, N2_vmr, O2, and O variables on the original data files before interpolation to constant height levels. The Joule heating power QJ [W/m3] was calculated using Q_J=_P B^2 [(u_i-u_n )^2+(v_i-v_n )^2+(w_i-w_n )^2] with P = Pedersen conductivity [S], B = geomagnetic field strength [T], ui, vi, and wi = zonal, meridional, and vertical ion velocities [m/s] and un, vn, and wn = neutral wind velocities [m/s]. QJ was integrated vertically in height (using a 2.5 km height grid spacing rather than the 61 levels on output file type 4) to give the JHH variable on the type 4 data files. The QJOULE variable also given is the Joule heating rate [K/s] at each of the 61 height levels. All data are provided as monthly mean files with one time record per file, giving 792 files for each data file type for the period 1950-2015 (66 years).

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model data for 1997.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model actual grid data.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model data for OP3.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model forecast data for 1997.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model data for 1995.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model forecast data for 1996.

Supporting model output from the Met Office's Air Quality Unified Model (AQUM) were made available to participants during the NERC funded RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere) consortium project. The overall objective of this consortium project was to advance substantially our understanding of night-time chemical processes and their impacts on the troposphere through a combined programme of instrument development, airborne measurements and numerical modelling. This dataset contains model output images of chemical species. These data cover 2010 period only.

Datasets of 5 day back trajectories have been computed on a routine basis using analyses from the European Centre for Medium Range Weather Forecasting (ECMWF). The three components of the wind and surface pressure over three launch grids covering the UK, the mid-Atlantic storm track region and the eastern USA, plus back trajectories from field campaign instrument sites were used to output datasets consisting of latitude, longitude and pressure of the trajectory every 30 minutes. This dataset contains ECMWF trajectories model data for PUMA.