Hannah Christensen

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Hannah Christensen

NERC Research Fellowship

Hannah M. Christensen

I am a Natural Environment Research Council Independent Research Fellow, based in the Atmospheric Oceanic and Planetary Physics Department at the University of Oxford. Previously I worked at the US National Center for Atmospheric Research as an Advanced Study Program Postdoctoral Fellow.

For up to date information on my work, please visit my personal webpage.

Publications

N.B. Publishing under H. M. Arnold prior to May 2014, and under H. M. Christensen after May 2014.

For an up to date publications list, please visit my personal webpage.

Roberts, M. J., Vidale P. L., Senior, C., Hewitt, H. T., Chang, P., Christensen, H. M., Danilov, S., Demory, M.-E., Griffies, S. M., Haarsma, R., Jung, T., Martin, G. Minobe, S., Ringler, T., Satoh, M., Schiemann, R. Scoccimarro, E., Stephens, G., Wehner, M. F., The benefits of global high-resolution for climate simulation: process-understanding and the enabling of stakeholder decisions at the regional scale. Submitted to Bull. Amer. Met. Soc

Strømmen, K, Christensen, H. M., Berner, J. and Palmer, T. N., The impact of stochastic parametrisations on the representation of the Asian summer monsoon. In press, Climate Dynamics

Leutbecher, M., Lock, S.-J., Ollinaho, P., Lang, S., Balsamo, G., Bechtold, P., Bonavita, M., Christensen, H. M., Diamantakis, M., Dutra, E., English, S., Fisher, M., Forbes, R., Goddard, J., Haiden, T., Hogan, R., Juricke, S., Lawrence, H., MacLeod, D., Magnusson, L., Malardel, S., Massart, S., Sandu, I., Smolarkiewicz, P., Subramanian, A., Vitart, F., Wedi, N., Weisheimer, A., Stochastic representations of model uncertainties at ECMWF: State of the art and future vision. In press, Q. J. Roy Meteor Soc.

Christensen, H. M., Lock, S.-J., Moroz, I. M., and Palmer, T. N., 2017, Introducing Independent Patterns into the Stochastically Perturbed Parametrisation Tendencies (SPPT) scheme. Q. J. Roy Meteor Soc. 143 (706), 2168–2181

Davini, P., von Hardenberg, J., Corti, S., Christensen, H. M., Juricke, S., Subramanian, A., Watson, P. A. G., Weisheimer, A. and Palmer, T., 2017, Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in the EC-Earth global climate model. Geosci. Model Dev., 10 1383–1402.

Berner, J., Achatz, A., Batte, L., de la Camara, A., Christensen, H. M., Colangeli, M., Coleman, D., Crommelin, D., Dolaptchiev, S. I., Franzke, C. L. E., Friederichs, P., Imkeller, P., Jarvinen, H., Juricke, S., Kitsios, V., Lott, F., Lucarini, V., Mahajan, S., Palmer, T. N., Penland, C., Sakradzija, M., von Storch, J.-S., Weisheimer, A., Weniger, M., Williams, P. D., and Yano, J.-I., 2017, Stochastic Parameterization: Towards a new view of Weather and Climate Models. Bull. Amer. Met. Soc. 98(3), 565–588.

Christensen, H. M., Berner, J., Coleman, D., and Palmer, T. N., 2017, Stochastic Parametrisation and the El Nin ̃o-Southern Oscillation. J. Climate. 30(1), 17-38.

Christensen, H. M., 2016, Contribution to the discussion on ‘Of quantiles and expectiles: consistent scoring functions, Choquet representations and forecast rankings’ by W Ehm et al. Journal of the Royal Statistical Society B. 78 (3), 505–562.

Christensen, H. M., 2016, Can randomness reduce uncertainty? The use of stochastic physics in weather and climate prediction, presented at the Royal Astronomical Society Astronomy and Geophysics Meeting, November 2015. The Observatory (April 2016)

Christensen, H. M., Moroz, I. M. and Palmer, T. N., 2015, Stochastic and perturbed parameter representations of model uncertainty in convection parametrization. J. Atmos. Sci., 72, 2525–2544.

Christensen, H. M., 2015, Decomposition of a New Proper Score for Verification of Ensemble Forecasts. Mo. Weath. Review, 143, 1517–1532.

Christensen, H. M., Moroz, I. M. and Palmer, T. N., 2015, Simulating Weather Regimes: impact of stochastic and perturbed parameter schemes in a simple atmospheric model. Climate Dynamics. 44(7), 2195-2214

Christensen, H. M., Moroz, I. M. and Palmer, T. N., 2015, Evaluation of ensemble forecast uncertainty using a new proper score: application to medium-range and seasonal forecasts.. Q. J. Roy. Meteor. Soc. 141(687), 538-549.

Watson, P. A. G., Christensen, H. M., and Palmer, T. N., 2015, Does the ECMWF IFS convection parameterisation with stochastic physics correctly reproduce relationships between convection and the large-scale state? J. Atmos. Sci., 72, 236-242.

Arnold, H. M., 2013, "Stochastic Parametrisation and Model Uncertainty", Doctoral Thesis, University of Oxford.

Arnold, H. M., 2013, Should weather and climate prediction models be deterministic or stochastic? Weather, 68(10), p264.

Arnold, H. M., Moroz, I. M. and Palmer, T. N., 2013, Stochastic Parametrizations and Model Uncertainty in the Lorenz '96 System,Phil Trans R Soc A, 371: 20110479

Invited Conference Talks and Seminars

NCAS-Climate Seminar, University of Reading UK (date tbc)
Applied Math Seminar, University of California, Berkeley, USA. (date tbc)
Clouds and Boundary Layer Processes Workshop, ETH Zürich, Switzerland. 13-15 Jun 2016
Computational Statistics Seminar, Heidelberg Institute for Theoretical Studies, Germany, Mar 2016
American Geophysical Union Fall Meeting, San Francisco, CA, USA Dec 2015
Royal Astronomical Society Ordinary Meeting (Keith Runcorn Prize Lecture), London, UK Nov 2015
Conference on Meteorology And Climate - Modeling for Air Quality (unable to accept invitation), Sacramento, CA, USA. Sep 2015
OpenIFS user meeting, ECMWF, Reading, UK. Jun 2015
Stochastic Parametrisation Workshop, ECMWF, Reading, UK. Mar 2015
Dynamical Systems Seminar Series, University of Colorado Boulder, CO, USA. Sep 2014
Workshop on Representing Uncertainty Across Timescales, Met Office, Exeter. Mar 2014
Atmospheric, Oceanic and Planetary Physics Seminar Series, University of Oxford. Mar 2014
CWC/SRM Meeting on Global Climate Modelling, Institute of Physics, London. Feb 2014
Centre for Atmospheric Science Seminar Series, University of Cambridge. Feb 2014
Internal Seminar Series, European Centre for Medium Range Weather Forecasts, Reading. Jan 2014

Prizes

Lloyds Science of Risk Peter Taylor Prize, runner up, for outstanding contribution of insurance understanding of natural hazards

This prize was awarded at the Lloyds Science of Risk conference 2016 for our paper Stochastic Parametrisation and the El Nin ̃o-Southern Oscillation, J. Climate (in press).

RAS Keith Runcorn Prize 2014: best doctoral thesis in Geophysics

I was invited to give the Keith Runcorn Prize lecture at the RAS Ordinary Meeting in November 2015.

Corpus Christi Junior Research Fellowship

From October 2013 to September 2016, I was a Junior Research Fellow at Corpus Christi College, Oxford.

Jesus College Graduate Scholarship

From September 2012, I have been awarded a Graduate Scholarship by Jesus College.

SET for Britain

I recently won the Silver Award in the SET for Britain 2012 Competition held in the House of Commons on Monday 12th March.

I discussed my poster, "Reliably Predicting Uncertainty in Weather and Climate Forecasts", with my local MPs, Gareth Thomas (Harrow West) and Andrew Smith (Oxford East), as well as with my fellow participants.

Thanks to the Society of Biology for the photos.

AOPP Johnson Prize

I was awarded the Atmospheric, Oceanic and Planetary Physics Johnson Prize for my Transfer of Status report. (October 2011)

Teaching

I hold a Lectureship in Physics at Corpus Christi College, Oxford (2018-19).

I taught the NERC Doctoral Training Programme, Advanced Training Workshop on Chaos and Uncertainty in Weather Forecasts, in May 2016, together with Aneesh Subramanian and Peter Dueben.

I taught revision tutorials in Classical Mechanics for Part A (second year) Mathematicians in Trinity 2011 and Trinity 2013.

I have been teaching tutorials in "Flows, Fluctuations and Complexity" to Part B (third year) physicists since 2012.

I taught classes in "Atmospheric, Oceanic and Planetary Physics" to Part C (fourth year) physicists in 2016.

I have supervised several summer undergraduate student projects:
2016: Ben Macrae. "Extreme weather and circulation regimes in the Weather@Home ensemble", with Peter Watson
2015: Michael Varley. "Improving Probabilistic Weather and Climate Predictions", with Peter Watson
2013: Tom Bolton. "Stochastic processors and inexact computing for weather and climate prediction" with Peter Dueben

Media: Podcasts

Oxford Sparks podcast, published online 4th Nov 2016

“In Press” UK science podcast and accompanying blog, published online, 15th Aug 2016

“The Other Half” US science podcast, published online, 4th Apr 2016

Media: Articles

Outlook for the weekend? Chilly, with a chance of confusion
A short article published in Significance, the magazine of the Royal Statistical Society and the American Statistical Association, discussing how statistics is important when making probabilistic forecasts. (October 2015)

Banking on better forecasts: the new maths of weather prediction
A short article on the Guardian website, discussing how we use computer simulators to make a weather forecast. Suitable for a mathematically literate audience. (January 2015)

Butterflies and Hurricanes: The Science of Weather Prediction
A general interest article written for the Corpus Christi College, Oxford, Alumni newsletter, The Sundial. (September 2014)

Predicting Predictability
A short article published in the Oxford Physics Department's newsletter (page 3), suitable for a general audience. (July 2012)

Other

I graduated in 2010 from Pembroke College, Cambridge with a Masters degree in Natural Sciences, specialising in Physics. My Masters project was entitled “Improving the Representation of Convective Clouds in Climate Models”, supervised by Dr Michael Herzog. I investigated ways to alter the description of entrainment in an existing deep convective cloud parametrisation scheme, CCFM. The model for entrainment was motivated by direct measurements in the Active Tracer High-Resolution Atmospheric Model (ATHAM), which is capable of explicitly resolving cloud processes.

I studied for my D.Phil., at Jesus College, Oxford, where I was also president of the Middle Common Room between 2011-2012. In this role, I represented the graduate community at Jesus on a college and university level. I am now a Junior Research Fellow at Corpus Christi College, Oxford.

My husband Nikolaj is a PhD student at the University of Birmingham.