Publications


A dynamical systems explanation of the Hurst effect and atmospheric low-frequency variability.

Scientific reports 5 (2015) 9068-

CL Franzke, SM Osprey, P Davini, NW Watkins

The Hurst effect plays an important role in many areas such as physics, climate and finance. It describes the anomalous growth of range and constrains the behavior and predictability of these systems. The Hurst effect is frequently taken to be synonymous with Long-Range Dependence (LRD) and is typically assumed to be produced by a stationary stochastic process which has infinite memory. However, infinite memory appears to be at odds with the Markovian nature of most physical laws while the stationarity assumption lacks robustness. Here we use Lorenz's paradigmatic chaotic model to show that regime behavior can also cause the Hurst effect. By giving an alternative, parsimonious, explanation using nonstationary Markovian dynamics, our results question the common belief that the Hurst effect necessarily implies a stationary infinite memory process. We also demonstrate that our results can explain atmospheric variability without the infinite memory previously thought necessary and are consistent with climate model simulations.


The stratospheric wintertime response to applied extratropical torques and its relationship with the annular mode

CLIMATE DYNAMICS 44 (2015) 2513-2537

PAG Watson, LJ Gray


Observation of seasonal variation of atmospheric multiple-muon events in the MINOS Near and Far Detectors

PHYSICAL REVIEW D 91 (2015) ARTN 112006

P Adamson, I Anghel, A Aurisano, G Barr, M Bishai, A Blake, GJ Bock, D Bogert, SV Cao, CM Castromonte, S Childress, JAB Coelho, L Corwin, D Cronin-Hennessy, JK de Jong, AV Devan, NE Devenish, MV Diwan, CO Escobar, JJ Evans, E Falk, GJ Feldman, MV Frohne, HR Gallagher, RA Gomes, MC Goodman, P Gouffon, N Graf, R Gran, K Grzelak, A Habig, SR Hahn, J Hartnell, R Hatcher, A Holin, J Huang, J Hylen, GM Irwin, Z Isvan, C James, D Jensen, T Kafka, SMS Kasahara, G Koizumi, M Kordosky, A Kreymer, K Lang, J Ling, PJ Litchfield, P Lucas, WA Mann, ML Marshak, N Mayer, C McGivern, MM Medeiros, R Mehdiyev, JR Meier, MD Messier, WH Miller, SR Mishra, SM Sher, CD Moore, L Mualem, J Musser, D Naples, JK Nelson, HB Newman, RJ Nichol, JA Nowak, J O'Connor, M Orchanian, S Osprey, RB Pahlka, J Paley, RB Patterson, G Pawloski, A Perch, S Phan-Budd, RK Plunkett, N Poonthottathil, X Qiu, A Radovic, B Rebel, C Rosenfeld, HA Rubin, MC Sanchez, J Schneps, A Schreckenberger, P Schreiner, R Sharma, A Sousa, N Tagg, RL Talaga, J Thomas, MA Thomson, X Tian, A Timmons, SC Tognini, R Toner, D Torretta, J Urheim, P Vahle, B Viren, A Weber, RC Webb, C White, L Whitehead, LH Whitehead, SG Wojcicki, R Zwaska, MINOS Collaboration


Possible impacts of a future Grand Solar Minimum on climate: Stratospheric and global circulation changes

Journal of Geophysical Research: Atmospheres (2015) n/a-n/a

AC Maycock, S Ineson, LJ Gray, AA Scaife, JA Anstey, M Lockwood, N Butchart, SC Hardiman, DM Mitchell, SM Osprey


The stratospheric wintertime response to applied extratropical torques and its relationship with the annular mode

Climate Dynamics 44 (2015) 2513-2537

PAG Watson, LJ Gray, LJ Gray

© 2014, The Author(s). The response of the wintertime Northern Hemisphere (NH) stratosphere to applied extratropical zonally symmetric zonal torques, simulated by a primitive equation model of the middle atmosphere, is presented. This is relevant to understanding the effect of gravity wave drag (GWD) in models and the influence of natural forcings such as the quasi-biennial oscillation (QBO), El Ninõ-Southern Oscillation (ENSO), solar cycle and volcanic eruptions on the polar vortex. There is a strong feedback due to planetary waves, which approximately cancels the direct effect of the torque on the zonal acceleration in the steady state and leads to an EP flux convergence response above the torque’s location. The residual circulation response is very different to that predicted assuming wave feedbacks are negligible. The results are consistent with the predictions of ray theory, with applied westerly torques increasing the meridional potential vorticity gradient, thus encouraging greater upward planetary wave propagation into the stratosphere. The steady state circulation response to torques applied at high latitudes closely resembles the Northern annular mode (NAM) in perpetual January simulations. This behaviour is analogous to that shown by the Lorenz system and tropospheric models. Imposed westerly high-latitude torques lead counter-intuitively to an easterly zonal mean zonal wind (Formula Presented.) response at high latitudes, due to the wave feedbacks. However, in simulations with a seasonal cycle, the feedbacks are qualitatively similar but weaker, and the long-term response is less NAM-like and no longer easterly at high latitudes. This is consistent with ray theory and differences in climatological (Formula Presented.) between the two types of simulations. The response to a tropospheric wave forcing perturbation is also NAM-like. These results suggest that dynamical feedbacks tend to make the long-term NH extratropical stratospheric response to arbitrary external forcings NAM-like, but only if the feedbacks are sufficiently strong. This may explain why the observed polar vortex responses to natural forcings such as the QBO and ENSO are NAM-like. The results imply that wave feedbacks must be understood and accurately modelled in order to understand and predict the influence of GWD and other external forcings on the polar vortex, and that biases in a model’s climatology will cause biases in these feedbacks.


Global distributions of overlapping gravity waves in HIRDLS data

Atmospheric Chemistry and Physics Discussions 15 (2015) 4333-4382

CJ Wright, SM Osprey, JC Gille


Does the ECMWF IFS Convection Parameterization with Stochastic Physics Correctly Reproduce Relationships between Convection and the Large-Scale State?

JOURNAL OF THE ATMOSPHERIC SCIENCES 72 (2015) 236-242

PAG Watson, HM Christensen, TN Palmer


The NuMI Neutrino Beam

ArXiv (2015)

P Adamson, K Anderson, M Andrews, R Andrews, I Anghel, D Augustine, A Aurisano, S Avvakumov, DS Ayres, B Baller, B Barish, G Barr, WL Barrett, RH Bernstein, J Biggs, M Bishai, A Blake, V Bocean, GJ Bock, DJ Boehnlein, D Bogert, K Bourkland, SV Cao, CM Castromonte, S Childress, BC Choudhary, JAB Coelho, JH Cobb, L Corwin, D Crane, JP Cravens, D Cronin-Hennessy, RJ Ducar, JKD Jong, AV Devan, NE Devenish, MV Diwan, AR Erwin, CO Escobar, JJ Evans, E Falk, GJ Feldman, TH Fields, R Ford, MV Frohne, HR Gallagher, V Garkusha, RA Gomes, MC Goodman, P Gouffon, N Graf, R Gran, N Grossman, K Grzelak, A Habig, SR Hahn, D Harding, D Harris, PG Harris, J Hartnell, R Hatcher, S Hays, K Heller, A Holin, J Huang, J Hylen, A Ibrahim, D Indurthy, GM Irwin, Z Isvan, DE Jaffe, C James, D Jensen, J Johnstone, T Kafka, SMS Kasahara, G Koizumi, S Kopp, M Kordosky, A Kreymer, K Lang, C Laughton, G Lefeuvre, J Ling, PJ Litchfield, L Loiacono, P Lucas, WA Mann, A Marchionni, ML Marshak, N Mayer, C McGivern, MM Medeiros, R Mehdiyev, JR Meier, MD Messier, DG Michael, RH Milburn, JL Miller, WH Miller, SR Mishra, SM Sher, CD Moore, J Morfin, L Mualem, S Mufson, S Murgia, M Murtagh, J Musser, D Naples, JK Nelson, HB Newman, RJ Nichol, JA Nowak, JO Connor, WP Oliver, M Olsen, M Orchanian, S Osprey, RB Pahlka, J Paley, A Para, RB Patterson, T Patzak, Z Pavlovic, G Pawloski, A Perch, EA Peterson, DA Petyt, MM Pfutzner, S Phan-Budd, RK Plunkett, N Poonthottathil, P Prieto, D Pushka, X Qiu, A Radovic, RA Rameika, J Ratchford, B Rebel, R Reilly, C Rosenfeld, HA Rubin, K Ruddick, MC Sanchez, N Saoulidou, L Sauer, J Schneps, D Schoo, A Schreckenberger, P Schreiner, P Shanahan, R Sharma, W Smart, C Smith, A Sousa, A Stefanik, N Tagg, RL Talaga, G Tassotto, J Thomas, J Thompson, MA Thomson, X Tian, A Timmons, D Tinsley, SC Tognini, R Toner, D Torretta, I Trostin, G Tzanakos, J Urheim, P Vahle, K Vaziri, E Villegas, B Viren, G Vogel, RC Webber, A Weber, RC Webb, A Wehmann, C White, L Whitehead, LH Whitehead, SG Wojcicki, ML Wong-Squires, T Yang, FX Yumiceva, V Zarucheisky, R Zwaska

This paper describes the hardware and operations of the Neutrinos at the Main Injector (NuMI) beam at Fermilab. It elaborates on the design considerations for the beam as a whole and for individual elements. The most important design details of individual components are described. Beam monitoring systems and procedures, including the tuning and alignment of the beam and NuMI long-term performance, are also discussed.


Report on the 1st QBO Modelling and Reanalyses Workshop

(2015) 45

J Anstey, K Hamilton, SM Osprey, N Butchart, LJ Gray


Mechanisms for the Holton-Tan relationship and its decadal variation

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 119 (2014) 2811-2830

H Lu, TJ Bracegirdle, T Phillips, A Bushell, L Gray


Northern winter climate change: Assessment of uncertainty in CMIP5 projections related to stratosphere-troposphere coupling

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 119 (2014) ARTN 2013JD021403

E Manzini, AY Karpechko, J Anstey, MP Baldwin, RX Black, C Cagnazzo, N Calvo, A Charlton-Perez, B Christiansen, P Davini, E Gerber, M Giorgetta, L Gray, SC Hardiman, Y-Y Lee, DR Marsh, BA McDaniel, A Purich, AA Scaife, D Shindell, S-W Son, S Watanabe, G Zappa


How Does the Quasi-Biennial Oscillation Affect the Stratospheric Polar Vortex?

JOURNAL OF THE ATMOSPHERIC SCIENCES 71 (2014) 391-409

PAG Watson, LJ Gray


Observation of muon intensity variations by season with the MINOS far detector

Physical Review D - Particles, Fields, Gravitation and Cosmology 81 (2010)

P Adamson, C Andreopoulos, KE Arms, R Armstrong, DJ Auty, DS Ayres, C Backhouse, J Barnett, G Barr, WL Barrett, BR Becker, M Bishai, A Blake, B Bock, GJ Bock, DJ Boehnlein, D Bogert, C Bower, S Cavanaugh, JD Chapman, D Cherdack, S Childress, BC Choudhary, BC Choudhary, JH Cobb, SJ Coleman, D Cronin-Hennessy, AJ Culling, IZ Danko, JK De Jong, JK De Jong, NE Devenish, MV Diwan, M Dorman, CO Escobar, JJ Evans, JJ Evans, E Falk, GJ Feldman, TH Fields, MV Frohne, MV Frohne, HR Gallagher, A Godley, MC Goodman, P Gouffon, R Gran, EW Grashorn, EW Grashorn, EW Grashorn, K Grzelak, K Grzelak, A Habig, D Harris, PG Harris, J Hartnell, J Hartnell, R Hatcher, K Heller, A Himmel, A Holin, J Hylen, GM Irwin, Z Isvan, DE Jaffe, C James, D Jensen, T Kafka, SMS Kasahara, G Koizumi, S Kopp, M Kordosky, M Kordosky, K Korman, DJ Koskinen, DJ Koskinen, DJ Koskinen, Z Krahn, A Kreymer, K Lang, J Ling, PJ Litchfield, L Loiacono, P Lucas, J Ma, WA Mann, ML Marshak, JS Marshall, N Mayer, AM McGowan, AM McGowan, AM McGowan, R Mehdiyev, JR Meier, MD Messier, CJ Metelko, DG Michael, WH Miller, SR Mishra, J Mitchell

The temperature of the upper atmosphere affects the height of primary cosmic ray interactions and the production of high-energy cosmic ray muons which can be detected deep underground. The MINOS far detector at Soudan, MN, has collected over 67×106 cosmic ray induced muons. The underground muon rate measured over a period of five years exhibits a 4% peak-to-peak seasonal variation which is highly correlated with the temperature in the upper atmosphere. The coefficient, αT, relating changes in the muon rate to changes in atmospheric temperature was found to be αT=0.873±0. 009(stat)±0.010(syst). Pions and kaons in the primary hadronic interactions of cosmic rays in the atmosphere contribute differently to αT due to the different masses and lifetimes. This allows the measured value of αT to be interpreted as a measurement of the K/π ratio for Ep 7TeV of 0.12-0.05+0.07, consistent with the expectation from collider experiments. © 2010 The American Physical Society.


Observation of muon intensity variations by season with the MINOS near detector

PHYSICAL REVIEW D 90 (2014) ARTN 012010

P Adamson, I Anghel, A Aurisano, G Barr, M Bishai, A Blake, GJ Bock, D Bogert, SV Cao, CM Castromonte, S Childress, JAB Coelho, L Corwin, D Cronin-Hennessy, JK de Jong, AV Devan, NE Devenish, MV Diwan, CO Escobar, JJ Evans, E Falk, GJ Feldman, TH Fields, MV Frohne, HR Gallagher, RA Gomes, MC Goodman, P Gouffon, N Graf, R Gran, K Grzelak, A Habig, SR Hahn, J Hartnell, R Hatcher, A Holin, J Huang, J Hylen, GM Irwin, Z Isvan, C James, D Jensen, T Kafka, SMS Kasahara, G Koizumi, M Kordosky, A Kreymer, K Lang, J Ling, PJ Litchfield, P Lucas, WA Mann, ML Marshak, M Mathis, N Mayer, C McGivern, MM Medeiros, R Mehdiyev, JR Meier, MD Messier, WH Miller, SR Mishra, SM Sher, CD Moore, L Mualem, J Musser, D Naples, JK Nelson, HB Newman, RJ Nichol, JA Nowak, J O'Connor, M Orchanian, S Osprey, RB Pahlka, J Paley, RB Patterson, G Pawloski, A Perch, S Phan-Budd, RK Plunkett, N Poonthottathil, X Qiu, A Radovic, B Rebel, C Rosenfeld, HA Rubin, MC Sanchez, J Schneps, A Schreckenberger, P Schreiner, R Sharma, A Sousa, N Tagg, RL Talaga, J Thomas, MA Thomson, X Tian, A Timmons, SC Tognini, R Toner, D Torretta, J Urheim, P Vahle, B Viren, A Weber, RC Webb, C White, L Whitehead, LH Whitehead, SG Wojcicki, R Zwaska, MINOS Collaboration


Interaction of gravity waves with the QBO: A satellite perspective

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 119 (2014) 2329-2355

M Ern, F Ploeger, P Preusse, JC Gille, LJ Gray, S Kalisch, MG Mlynczak, RJM III, M Riese


Skillful Seasonal Prediction of the Southern Annular Mode and Antarctic Ozone

JOURNAL OF CLIMATE 27 (2014) 7462-7474

WJM Seviour, SC Hardiman, LJ Gray, N Butchart, C MacLachlan, AA Scaife


A mechanism for lagged North Atlantic climate response to solar variability

Geophysical Research Letters 40 (2013) 434-439

AA Scaife, S Ineson, JR Knight, L Gray, K Kodera, DM Smith

Variability in solar irradiance has been connected to changes in surface climate in the North Atlantic through both observational and climate modelling studies which suggest a response in the atmospheric circulation that resembles the North Atlantic Oscillation or its hemispheric equivalent the Arctic Oscillation. It has also been noted that this response appears to follow the changes in solar irradiance by a few years, depending on the exact indicator of solar variability. Here we propose and test a mechanism for this lag based on the known impact of atmospheric circulation on the Atlantic Ocean, the extended memory of ocean heat content anomalies, and their subsequent feedback onto the atmosphere. We use results from climate model experiments to develop a simple model for the relationship between solar variability and North Atlantic climate. © 2013. American Geophysical Union. All Rights Reserved.


Stratospheric variability in 20th Century CMIP5 simulations of the Met Office climate model: High-top versus low-top

J CLIM 26 (2013) 5

SM Osprey, LJ Gray, SC Hardiman, N Butchart, T Hinton


The impact of stratospheric resolution on the detectability of climate change signals in the free atmosphere

GEOPHYSICAL RESEARCH LETTERS 40 (2013) 937-942

DM Mitchell, PA Stott, LJ Gray, MR Allen, FC Lott, N Butchart, SC Hardiman, SM Osprey


Recent variability of the solar spectral irradiance and its impact on climate modelling

ATMOSPHERIC CHEMISTRY AND PHYSICS 13 (2013) 3945-3977

I Ermolli, K Matthes, TD de Wit, NA Krivova, K Tourpali, M Weber, YC Unruh, L Gray, U Langematz, P Pilewskie, E Rozanov, W Schmutz, A Shapiro, SK Solanki, TN Woods