Evaluation of ensemble forecast uncertainty using a new proper score: Application to medium‐range and seasonal forecasts

Quarterly Journal of the Royal Meteorological Society Wiley 141:687 (2015) 538-549

Authors:

HM Christensen, IM Moroz, TN Palmer

Stochastic Parameterisations and Model Uncertainty in the Lorenz '96 system

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Royal Society 371 (2013) 20110479

Authors:

HM Arnold, IM Moroz, TN Palmer

Should weather and climate prediction models be deterministic or stochastic?

Weather Wiley 68:10 (2013) 264-264

Aerodynamic Stability and the Growth of Triangular Snow Crystals

The Microscope McCrone Research Institute 4:57 (2009) 157-163

Authors:

KG Libbrecht, HM Arnold

Abstract:

We describe laboratory-grown snow crystals that exhibit a triangular, plate-like morphology, and we show that the occurrence of these crystals is much more frequent than one would expect from random growth perturbations of the more-typical hexagonal forms. We then describe an aerodynamic model that explains the formation of these crystals. A single growth perturbation on one facet of a hexagonal plate leads to air flow around the crystal that promotes the growth of alternating facets. Aerodynamic effects thus produce a weak growth instability that can cause hexagonal plates to develop into triangular plates. This mechanism solves a very old puzzle, as observers have been documenting the unexplained appearance of triangular snow crystals in nature for nearly two centuries.

Advancing Organized Convection Representation in the Unified Model: Implementing and Enhancing Multiscale Coherent Structure Parameterization

Journal of Advances in Modelling Earth Systems

Authors:

Hannah Christensen, Zhixiao Zhang, Mark Muetzelfeldt, Tim Woollings, Robert Plant, Alison Stirling, Michael Whitall, Mitch Moncrieff, Chih-Chih Chen, Zhe Feng