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model

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  • 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 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.

  • 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).

  • 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.

  • Near real time output from the Met Office's operational Unified Model (UM) supplied participants of the Convective Storm Initiation Project (CSIP) aimed to further the understanding of the mechanisms responsible for the initiation of precipitating convection in the maritime environment of southern England. The CSIP project aimed to understand why convective clouds form and develop into precipitating clouds in a particular location. The project was centred on the 3 GHz (CAMRa) and 1275 clear-air (ACROBAT) radars at Chilbolton and used a number of the new UK Universities' Facility for Atmospheric Measurement (UFAM) mobile instruments.

  • This dataset contains WACCM-X model results under RCP8.5 (Representative Concentration Pathway) carbon dioxide increases and high solar activity (F10.7 = 200 sfu). These cover ground level to a pressure level of 4e-10 hPa (~300 km altitude) on a global 144x96 longitude-latitude grid . Data is given in daily instantaneous (.h2.) and monthly average (.h0.) files in the netCDF format. Default WACCM-X outputs remain, along with the following additional variables: 'PS' - Surface Pressure 'Z3' - Geopotential Height (above sea level) 'T' - Temperature 'U' - Zonal Wind 'V' - Meridional Wind 'CO2' - Carbon Dioxide Concentration 'CO' - Carbon Monoxide Concentration 'NO' - Nitric Oxide Concentration 'H2O' - Water Vapour Concentration 'O' - Atomic Oxygen Concentration More detail on each variable is given within the netCDF files and the readme file. 64 month runs from edited initial files at 10 year intervals from 2015 to 2095 under RCP8.5. There is also a 28 month 1975 run and 64 month 2000 run. All of these cyclically repeat the initial year. These are separated into individual folders with the RCP8.5 CO2 concentration listed. The first 4 months of each of these datasets have been ignored in processing as the model spins up, but are included here for completeness. This data was collected to understand the density drop at low earth orbit altitudes as carbon dioxide concentrations increase.

  • This dataset contains methane concentrations from a chemistry-climate model, focusing on year 2000 and year 2100. The present-day forcings were used for the 2000 simulation, while for year 2100 the Representative Concentration Pathway (RCP) RCP8.5 pathway were used. All experiments were run as perpetual timeslice experiments and are global model simulations made using the Met Office Unified Model at vn7.3 based on the HadGEM3-A science configuration. The model was run in atmosphere-only mode with a horizontal resolution of 2.5 degree latitude by 3.75 degree longitude, 60 vertical levels up to 84 km, and prescribed sea surface temperatures and sea ice extents. SST, sea ice and other forcings from earlier model experiments were used, e.g. Banerjee et al. (doi:/10.5194/acp-14-9871-2014). For the year 2000 experiments, greenhouse gas, ozone depleting substances and ozone precursor emissions are taken from the Coupled Model Intercomparison Project - Phase 5 (CMIP5) reference forcings, as in Lamarque, 2010 (doi.org/10.5194/acp-10-7017-2010). The data comprise a series of separate experiments designed to test the performance of methane emissions in this model and to compare against the default that uses a prescribed concentration at the surface, with a view to assessing the performance of the more physically realist emissions treatment. For year 2000, the model was run for three experiments: the first (BASE) experiments employ a set of emissions derived from EDGAR v4 to describe anthropogenic methane emissions, with biognenic emissions taken from the chemistry-transport model (CTM) intercomparison experiment (TransCom-CH4) paper of Patra et al, (DOI:10.5194/acp-11-12813-2011), a second set of experiments used identical emissions to BASE except that CO emissions were increased by 50% globally from the emissions of Lamarque, this is called Delta_CO, and a third year 2000 experiment used CMIP5 methane emissions from Lamarque (as above) rather than EDGAR and biogenic emissions derived from Melton et al. (https://doi.org/10.5194/bg-10-753-2013) rather than Patra. These experiments test the model skill in simulating methane based on the model treatment of emissions and establish the sensitivity to emissions. Three future climate experiments were also performed using climate forcings appropriate to year 2100 following the RCP8.5 pathway. We looked at the climate drivers in turn that arise as the climate changes. In the first, DELTA_CC, climate forcings were adjusted from greenhouse gases to year 2100 values, but kept methane and other anthropogenic forcings at year 2000 values, a second experiment, DELTA_CH4, adjusted CH4 to Year 2100 values from the emissions database as above, a third was an all-forcings experiments in which greenhouse gases, methane and ozone precursors were adjusted to RCP8.5 levels. This gave three separate experiments which explore how methane responds to these changes in the climate drivers.

  • 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.

  • 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 global data.