Thorwald Stein - Lecturer in Clouds
My Flickr photos of clouds|
(Last update: 30 November 2015)
This page presents an overview of the projects I am involved in. Please follow the Research link above to find relevant publications and/or presentations.
I have recently had a proposal funded as part of the CSSP-China research programme, led by the Met Office and supported through the Newton Fund. This research, jointly led with Juliane Schwendike at the University of Leeds, will study the microphysical and dynamical processes controlling the structure and variability of the East Asian monsoon Meiyu-Baiu front. We will use a season-long simulation of the monsoon at convection-permitting resolution to study improvements in representation of extreme rainfall events compared to global models.
For several months, I was involved in the EU funded DACCIWA project (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa).
Triple-wavelength retrievals (2014-2016)
I worked for five months with Chris Westbrook and John Nicol on the retrieval of ice-particle shape and size using radar reflectivity measurements at three different wavelengths. We used the 35-GHz and 94-GHz vertically pointing radars at Chilbolton, as well as the 3-GHz scanning radar (with 25-m dish) in its fixed mode, pointing upwards. For the smaller wavelengths, non-Rayleigh backscatter occurs at smaller particle sizes, so the difference in radar reflectivity from different wavelengths can be used to get a handle of mean particle diameter. We use this information to test ice-particle scattering models, for which we can calculate radar reflectivity values as well.
I worked for several years on the NERC funded DYMECS project (Dynamical and Microphysical Evolution of Convective Storms). I developed an algorithm to track convective storms in the UK using Met Office model data and radar-observed rainfall. A second algorithm, developed with Robin Hogan, used the information on rainfall regions (location, size) to track these storms in real-time with the Chilbolton 3GHz radar to obtain high-resolution information on their microphysical and dynamical evolution. Please visit the DYMECS website for more information, as well as presentations, publications, and quicklooks of all DYMECS cases.
In the NERC funded Cascade project project, we use the UK Met Office Unified Model (UM) with a limited-area model setup in the tropics. We analyse model runs over West Africa for the AMMA period of observations in the summer of 2006, and runs covering the Indian Ocean and tropical West Pacific for periods with a Madden-Julian oscillation (organised convective activity) propagating through the region.
My interests for this project lie in the evaluation of the UM cloud fields against satellite observations, in particular CloudSat and CALIPSO, using either radar reflectivities simulated from the model variables or cloud ice properties forward modelled from the observations. The detailed information in the vertical provided by CloudSat and CALIPSO allows us to study the occurrence of particular cloud types (cirrus, deep convection, marine stratocumulus) in the observations and to use these statistics to test the model. The observed variables (radar reflectivity and lidar backscatter) can be used to retrieve cloud ice properties, or for comparison with their values simulated from the model cloud fields, thus testing the model microphysics.
PhD in Mathematics (University of Warwick, 2004-2009)
Thesis: Modelling a large system of particles under different rules of merging
Further interests are statistical physics and fluid dynamics, with a focus on particle coagulation during my PhD at the Mathematics Institute at the University of Warwick under the supervision of professor Sergey Nazarenko.