Brief Description


Climate Models used by UKCA

The UKCA model runs within the Hadley Centre version of the Unified Model. There are a number of different versions of this climate model at a number of resolutions which are used for UKCA development.

UM Version Model Horizontal Resolution Vertical Levels Model Top Scheme Used
6.1 HadGAM1a N48 (2.5°×3.75°) L60 ~84km Tropospheric Chemistry
6.1 HadGAM2 N48 L60 ~84km Stratospheric Chemistry
6.6.4 HadGEM2-ES N96 L38 ~40km Hadley Centre Earth System Model
7.1 HadGEM3-A N96 (1.25°×1.875°) L38 ~40km Tropospheric Chemistry
7.3 HadGEM3-A r2.0 N96 L38 ~40km Tropospheric Chemistry
7.3 HadGEM3-A r2.0 N96 L63 ~40km Tropospheric Chemistry
7.3 HadGEM3-A r2.0 N96 L85   85km Stratospheric Chemistry
7.3 HadGEM3-A r2.0 N48 L60 ~84km Stratospheric Chemistry
7.3 HadGEM3-AO r2.0 N48 L60 ~84km QUEST Earth System Model

UKCA: Currently Available Chemistry Schemes

UKCA Aerosol Scheme: GLOMAP-mode


UKCA Development Timeline

If you are interested in using UKCA, and there is a particular piece of functionality that you would like or need, but are not sure if it is available, please contact Luke Abraham for further information.

Short-Term Development

  • Stratospheric Chemistry at UM7.3 HadGEM3-A (N96L85 and N48L60) - Luke Abraham
  • ASAD Flux Diagnostics at UM7.3 - Luke Abraham
  • Improved representation of isoprene oxidation at UM6.1 - Alex Archibald
  • Chemistry of Stratosphere and Troposphere - CheST at UM7.3 - Alex Archibald
  • Flight track emulator to compare to campaign data at UM7.3 - Paul Telford
  • Fast-JX photolysis code validation at UM7.3 - Paul Telford
  • Emissions Profiling from ExTC at 7.3- Paul Telford & Maria Russo
  • Interactive biogenic emissions from ExTC at 7.3- Paul Telford

Medium-Term Development

  • HadGEM3-AO UKCA - Luke Abraham
  • Satellite emulator, including averaging kernels, to improve validation at UM7.3 - Paul Telford
  • Couple mode aerosols and fast-jx code at UM7.3 - Paul Telford and ?
  • Shift UKCA emissions from Section 0 (user-defined) to Section 34 - Mohit Dalvi Sec34 emissions
  • Extend Weseley scheme dry deposition to match 2D scheme - Paul Telford

Long-Term Development

  • Coupled UKCA Stratosphere-Troposphere Chemistry with MODE

UKCA: Model Outline

Development of UKCA consists of the following subprojects:

Tropospheric model development

Stratospheric model development


  • New aerosol species and microphysics
  • Aerosol chemistry
  • Integrated Climate Programme report (Mar10) comparing CLASSIC and GLOMAP-mode in HadGEM3 Pdficon small.png ICP Report M3 Info circle.png.
  • Integrated Climate Programme report (Mar11) describing latest UKCA developments for HadGEM3 Pdficon small.png UKCA ICP March 2011 Info circle.png.
  • Scoping document for HadGEM3 recommends including GLOMAP-mode in UKCA for HadGEM3 Pdficon small.png HadGEM3-ES Scoping document Info circle.png.
  • Coupling of GLOMAP-mode aerosol to UM radiation scheme Pdficon small.png UKCA RADAER Info circle.png.
  • UKCA internal report: Comparison of UKCA modal dust scheme against the 6-bin CLASSIC scheme within MetUM Pdficon small.png UKCAdust Info circle.png.
  • Integrated Climate Programme report (Feb12): UKCA merged code ready to form part of version 8.2 of the Unified Model Pdficon small.png UKCA ICP Feb12 (merged code) Info circle.png.
  • MACC Deliverable report (Dec11): Implementation and evaluation of GLOMAP-mode in the IFS Pdficon small.png MACC Deliverable report D_G-AER1.8 Dec11 Info circle.png.
  • MACC-II Deliverable report (May13): Evaluation of aerosol optical depth in IFS-GLOMAPPdficon small.png MACC Deliverable report D_AER_62.3 May13 Info circle.png.

Aerosols Cloud Coupling

Aerosol Cloud Coupling: the modal UKCA scheme [Mann et al., 2010] has been coupled by Oxford and the MetOffice to the PC2 cloud scheme [Wilson et al., 2008] via an explicit Köhler theory based activation scheme [Abdul-Razzak & Ghan, 2000].

  • Features:
    • Sub-grid scale probability density function for updraft velocities coupled to turbulent kinetic energy
    • Coupling to cloud radiative properties (i.e. cloud albedo effects)
    • Coupling to precipitation formation scheme (i.e. cloud lifetime effects)
  • Publications:
    • West et al. (in preparation)

New features

  • Coupled chemistry, aerosols and climate model
  • Based on new dynamics
  • Combined troposphere-stratosphere chemistry
  • Improved aerosol microphysics and chemistry
  • Capability to interact with surface, radiation and biosphere
  • Modular structure