The Greenland Flow Distortion EXperiment investigates the role of Greenland in defining the structure and the predictability of both local and downstream weather systems, through a programme of aircraft-based observation and numerical modelling. The Greenland Flow Distortion Experiment (GFDex) will provide some of the first detailed in situ observations of the intense atmospheric forcing events that are thought to be important in modifying the ocean in this area (but are presently poorly understood): namely tip jets, barrier winds and mesoscale cyclones. The dataset contains Met Office forecast products.

The Unified Model is the name given to the suite of atmospheric and oceanic numerical modelling software developed and used at the Met Office. The formulation of the model supports global and regional domains and is applicable to a wide range of temporal and spatial scales that allow it to be used for both numerical weather prediction and climate modelling as well as a variety of related research activities. The Unified Model was introduced into operational service in 1991. Since then, both its formulation and capabilities have been substantially enhanced. Data from the operational NWP (Numerical Weather Prediction) output from the Met Office Unified Model. These data are from both the Global and the North Atlantic European (NAE) part of the model. The NAE model runs on a grid centred around the UK. Analyses and intermediate forecast steps are stored to give an hourly time resolution for 6 hours following each analysis time-step. This archive only holds data to January 2012. A new NWP archive is being populated with data from January 2012. The dataset starts on 23 October 2000, and is ongoing. Around 1.6Gb of data are stored for each day. Analysis fields at 0,6,12,18Z are stored, along with all of the forecast fields from 1-6 hours from each analysis time. Mesoscale : lb[a,f][m,p]yyyymmddhh_STASHCODE_fh.pp Global: ag[a,f][m,p]yyyymmddhh_STASHCODE_fh.pp where yyyymmddhh is the year, month,day and assimilation time, STASHCODE is the STASHMASTER parameter code, fh is the forecast timestep (from the assimilation time), and pp indicates that the files are in binary "pp" format. The directory structure has also been changed to bring it in line with the BADC ECMWF holdings. The mesoscale files and global data are now stored under: /badc/ukmo-um/data/meso/lb/a[m,p] for the analysis fields /badc/ukmo-um/data/meso/lb/f[m,p] for the forecast fields /badc/ukmo-um/data/global/ag/a[m,p] for the analysis fields /badc/ukmo-um/data/global/ag/f[m,p] for the forecast fields Pre-2004 data are still available in the old format under /badc/ukmo-um/data/mesocale/[sm,mm] and /badc/ukmo-um/data/global/[mg,sg], although these will be phased out as the data are archived in the newer format.

Cascade was a NERC funded consortium project to study organized convection in the tropical atmosphere using large domain cloud system resolving model simulations. This datset collection contains measurements from atmospheric model runs of the tropics. Within the Cascade project a version of the Met Office Unified Model (UM) at horizontal resolutions of 1.5km - 40km was used Africa, Indian Ocean and West Pacific Ocean. The horizontal resolution allowed the individual cloud systems to simulate the large-scale organization. The combination of the high resolution and large domains allowed the upscale transports of heat, moisture and momentum and investigated the impact of these transports on the evolution of the synoptic and planetary scale systems. Two domains of interest were chosen to represent continental and oceanic convection respectively. Simulations of the West African Monsoon region were used to understand the range of factors which influence the diurnal cycle of convection over complex topography and to identify the impact of the diurnal cycle and other mesoscale organization on the synoptic organization of convection by African Easterly Waves. Simulations of the Indian Ocean and West Pacific Warm Pool were used to investigate the role of mesoscale and synoptic scale organization on the evolution of the Madden-Julian Oscillation and the influence of the diurnal cycle (e.g. land-sea breeze circulations) on the maintenance of the climate of the Maritime Continent region. In addition, simulations over an idealized ocean surface were used to investigate the organization of convection by equatorially trapped wave modes.

This dataset contains operational NWP (Numerical Weather Prediction) output from the global atmospheric part of the Met Office global atmospheric Unified Model. The Met Office Unified Model is the numerical modelling system developed and used at the Met Office (it is run operationally for weather forecasting). It is 'seamless' in that different configurations of the same model are used across all time and space scales. This model can produce several datasets of which CEDA holds the following: Met Office Global Atmospheric Model data Met Office North Atlantic/European (NAE) Mesoscale Model data The Met Office Global Atmospheric Model has 25 km resolution with 70 vertical levels. It Covers the entire globe and 144 hours in the future twice a day. The Global model provides boundary information for the NAE model, for which additional shorter runs (48 hours) are produced twice a day. The model is kept close to the real atmosphere using hybrid 4D-Var data assimilation of observations. 17km resolution with 70 vertical levels is now also available. Analyses and first forecast steps are stored to give a time resolution of 1 hour up to 6 hours after each analysis timestep. The NWP global output archive starts on 1 January 2012, and is ongoing.

Cascade was a NERC funded consortium project to study organized convection and scale interactions in the tropical atmosphere using large domain cloud system resolving model simulations. This dataset contains data from the xfixa simulation which ran using the Met Office Unified Model (UM) at 12km horizontal resolution over the domain 20W-20E, 5S-28N which encompasses the west african monsoon. Cascade Africa simulations are used to study African Easterly Waves. This dataset contains 4km Africa model measurements from xfixa run.

Data from the operational NWP (Numerical Weather Prediction) output from the global atmospheric part of the Met Office Unified Model. Analyses and first forecast steps are stored to give an hourly time resolution for 6 hours following each analysis time-step. This dataset spans the period January 2012 to 28th March 2012.

Data from the operational NWP (Numerical Weather Prediction) output from the Variable resolution UK (UKV) part of the Met Office Unified Model. This latest configuration of the UM model has a high resolution inner domain (1.5 km grid boxes) over the area of forecast interest, separated from a coarser grid (4 km) near the boundaries by a variable resolution transition zone. This variable resolution approach allows the boundaries to be moved further away from the region of interest, reducing unwanted boundary effects on the forecasts. The UKV model is kept close to observations using 3D-Var data assimilation every 3 hours. This archive is currently being populated at the BADC.

ACCACIA was part of the NERC Arctic research programme. (NERC Reference: NE/I028858/1). ACCACIA aimed to improve our understanding of aerosol-cloud interactions in the Arctic, and the potential changes and feedbacks that may result from decreasing Arctic sea ice cover in the future. In situ measurements have been made during two field campaigns utilising ship-based measurements of surface aerosol sources and airborne measurements of aerosol and cloud microphysical properties, boundary layer dynamics, and radiative forcing. The observations have been complemented by modelling studies on a range of scales: from explicit aerosol and cloud microphysics process modelling, through large eddy simulation and mesoscale models, up to global climate models. This dataset contains measurements from the Met Office UM (Unified Model) model.

Data from the operational NWP (Numerical Weather Prediction) output from the global atmospheric part of the Met Office Unified Model. Analyses and first forecast steps are stored to give an hourly time resolution for 6 hours following each analysis time-step. This archive currently holds data from January 2012 onwards but data will be back populated for earlier years.

Data from the operational NWP (Numerical Weather Prediction) output from the global atmospheric part of the Met Office Unified Model. Analyses and first forecast steps are stored to give an hourly time resolution for 6 hours following each analysis time-step. This archive currently holds data from January 2012 onwards but data will be back populated for earlier years.