CSET – Development of a New Convective- and Turbulent Scale Evaluation Tool at the Met Office

Abstract: A robust approach to model evaluation is essential in supporting the efficient and useful delivery of continuous NWP development cycles. Evaluation underpins the development cycle of our Regional Atmosphere Land (RAL) science configurations used across a range of deterministic and probabilistic applications and underpins the use of RAL science for a variety of research areas in the Met Office.We are developing CSET, an open-source toolkit for evaluation, verification, and investigation of convective- and turbulence-scale numerical models for weather and climate applications, cutting across time and space scales. It will be the core engine of evaluation tools supporting our RAL configurations (UM and LFRic-based), ensuring best practice for verification and evaluation linked to RAL suites.CSET aims to be a community tool to harness the diversity in knowledge across the Met Office, UM partnership, and academia. It provides a home for further development and visibility of existing diagnostics, and we envisage it as the go-to place for researchers to develop and use process-oriented evaluation diagnostics for convective and turbulence-scale modelling systems. In addition, the use of formal software development techniques benefits reproducibility, portability, accessibility, maintainability, and quality assurance.CSET composes small functional units called operators into recipes to produce (new) diagnostics and can run them over case studies or continuous trials to produce a collection of diagnostics displayed on an interactive web page. CSET operators can be generic, like filtering or subtracting, or specific, like calculating the size distribution of storms in a precipitation field. The operators are chained together in a recipe which specifies which operators will be run, in which order and with which parameters.We will outline the main design principles of CSET, introduce how to use and contribute to CSET and current diagnostics available through an extreme weather case study.

Biography: James Frost is a Scientific Software Engineer working at the Met Office in regional model evaluation and development. He is the lead developer of the CSET evaluation tool.