School of GeoSciences

School of GeoSciences

Tim Arnold

Lecturer in the Global Change Research Institute and Senior Research Scientist at the National Physical Laboratory


My research helps improve our understanding of the sources and sinks of greenhouse gases. I study the changes in atmospheric composition happening now and the changes that have occurred over the last few decades. I am especially interested in the development and use of high-precision ground-based measurements that are sensitive to gas fluxes on local to regional to global scales. Sources and sinks can be quantified from these measurements using atmospheric transport models within a mathematical inversion framework. Developing novel measurement methods and improving the quality of information within this framework holds promise to reduce emissions estimate uncertainties, and most importantly, help focus climate change mitigation efforts.

I have a joint position between the National Physical Laboratory in London and the University of Edinburgh. The National Physical Laboratory is the UK's National Measurement Institute, which is responsible for traceability, accuracy and consistency of measurement from fundamental science through to delivery of services. At NPL I work in the Emissions and Atmospheric Metrology group - a team of 20+ scientists helping a range of organisations and companies quantify gaseous and particulate emissions important to climate and air quality.

Current work

1) Developing in situ, high precision measurements of methane isotopologues

2) Maintaining and interpreting high precision long term measurements in the UK for greenhouse gas emissions estimates on regional scales

3) Inverse modelling to understand sources and sinks of greenhouse gases on global and regional scales

4) Methods to understand industrial emissions at source


Before joining the National Physical Laboratory and the University of Edinburgh in 2016 I was at the Met Office Hadley Centre (2014-2016). Prior to this, I spent more than five years in the USA at the University of California, San Diego at the Scripps Institution of Oceanography as a postdoc studying atmospheric composition change (2009-2014). My undergraduate studies were in Natural Sciences at the University of Cambridge (2001-2005) and I followed this with a PhD in isotope geochemistry in the Earth Science and Engineering Department at Imperial College London (2005-2009).