An external view of the Met Office building at night.

Dr Humphrey Lean

Humphrey leads research into formulation and applications of convective-scale versions of the Unified Model.

Areas of expertise

  • Convective scale modelling

  • Convection and convective initiation

  • Orographic rainfall

  • Urban Meteorology

  • Use of the Unified Model and associated systems

  • Next generation 100m scale modelling

Publications by Humphrey Lean

Current activities

Humphrey manages the Convective Scale Modelling Research group at MetOffice@Reading. The overarching aim of the group is to undertake holistic development of  km and sub km scale versions of the Unified Model in collaboration with colleagues in the University of Reading Department of Meteorology. Currently the three major areas of work in the group are (i) to improve the explicit representation of convection in versions of the Unified Model with gridlengths between 1.5km and 100m, (ii) understanding predictability in convective scale models including development of high resolution ensembles and (iii) evaluation and improvement of km and sub km scale Unified Model versions in urban areas.

The Mesoscale Modelling group works closely with the MetOffice@Reading DA@Reading group which is aiming utilise novel observations in high resolution forecast systems.

Humphrey's personal interests lie in the areas of orographic rainfall (particularly the seeder-feeder effect), mesoscale structures in cyclones, convection and urban meteorology. An important aspect of Humphrey's work is to facilitate collaboration with colleagues in academia in particular with those in the  University of Reading Department of Meteorology where MetOffice@Reading  is located.

Career background

Humphrey's first degree was in Physics (University of Bristol Department of Physics) followed by a PhD in low temperature physics, specifically superconductivity (University of Cambridge Department of Physics). He carried out post-doctoral work on high-temperature superconductors and also worked for a couple of years at the Culham Centre for Fusion Energy on the tokamak fusion programme.

Humphrey joined the Met Office in 1995 and worked initially in the Weather Systems group with Sid Clough. In early 1997 the group was involved with the Fronts and Atlantic Storm tracks Experiment (FASTEX) and much of his work was involved in mesoscale modelling of cases from this. Particular areas of interest were the role of microphysical processes in cyclone development and system relative analysis.

In 1998 Humphrey moved into the  Mesoscale Modelling group with Peter Clark, but continued to work on related modelling for a while. In late 1999 he started work running the non-hydrostatic prototype of the Unified Model at higher resolutions than 12 km (then the highest in the operational system).  This, very quickly, showed encouraging results (initially for  cases). As a result,  Humphrey started the High Resolution Trial Model (HRTM) project in 2002 ,which established many aspects of the optimal configuration of the Unified Model at 4 km and 1 km resolutions, and included systematic trials to ascertain both the benefits and the problems with these models. This work led directly to the implementation of the UK 4 km model in the operational system in 2005 and the 1.5 km model in 2009.