JULES is a land surface model that simulates flows of energy, water, carbon and nitrogen between the land, atmosphere and soil. It operates at timescales from days to centuries and geographic scales from UK to global for a range of users: (1) Operational forecasters use JULES to predict weather-related hazards (eg floods, droughts); (2) IPCC and policy-makers use JULES to predict future climate change impacts; (3) Scientists use JULES to understand environmental processes and effects.
JULES is a UK research community model (see Partners) that contributes to: (a) the Met Office’s Unified Model used for weather forecasting in the UK; and (b) the UK Earth System Model (UKESM) used for IPCC climate projections. JULES can also be used in 'standalone' research mode to study land surface processes and impacts. JULES comprises computer code and configurations (information needed), and can be run on various computing platforms, from individual PCs to powerful supercomputers. It includes modules to account for the effects of hydrology, vegetation and soils on responses and feedbacks of the land surface with the atmosphere. It can simulate national (e.g. UK 1km grid) or global (e.g. 10km grid) scales. It describes processes that work on short timescales (e.g. hydrological response to a passing rain storm) and also on much longer timescales, such as changes in vegetation and soils over a hundred years in the past or future.
The first version of the JULES model was released in 2006. There are typically 3 releases per year; v6.4 was released in June 2022. As a community model JULES benefits from development by approximately 10 full-time equivalent (FTE) scientists, primarily located in UKCEH and the Met Office, but is used by a community of over 50 active users at any time. Further technical support is provided by the Met Office to ensure operational needs are met.
JULES is one of the leading land surface models in the world, and the only UK land surface model that simulates flows of energy, water, carbon and nitrogen between land, atmosphere and soil. It is used for both short term (days) and centennial-scale simulations. It represents and integrates processes that operate across a wide-range of timescales and space scales (from UK to global). It also integrates across domains (vegetation, soils, rivers) and across biogeochemcical cycles (water, energy, carbon, nitrogen). When used in combination with atmospheric and ocean models (e.g. in UKESM) it allows further integration to represent the coupled Earth System, and as such contributes to UK input to IPCC climate projections.
JULES is a UK research community model, co-developed and operated by a network including: UKCEH (lead); Met Office; Universities of Exeter, Reading, Leicester, Bristol and Edinburgh; with users in other universities. JULES is also used by international research centres, including Bureau of Meteorology (Australia), National Institute of Water and Atmospheric Research (New Zealand), National Centre for Medium Range Weather Forecasting (India), and others. JULES is part of the Met Office’s Unified Model used for weather forecasting and climate prediction in the UK; and the UK Earth System Model that contributes to IPCC climate projections.
JULES is an open access UK research community model: available to use at no cost for non-commerical users (see weblink). Selected model outputs can be found in various online repositories including the UKCEH Environmental Information Data Centre (EIDC).
Development of JULES was funded by: UKRI-NERC National Capability (LTSM programmes Hydro-JULES, UKESM and TerraFIRMA); Met Office; UKRI-NERC research project grants.
JULES is used by researchers in UK universities and institutes, and the international land surface modelling community (input to IPCC). JULES is part of the Unified Model, used operationally by national meteorological organisations and weather forecasters, including UK Met Office, Australia, India, New Zealand, Singapore, South Kora. JULES is also part of UKESM (Earth System Model), whose outputs are used by environmental policy organisations including UN IPCC for climate projections.