Imperial College London

ProfessorRalfToumi

Faculty of Natural SciencesDepartment of Physics

Professor of Atmospheric Physics
 
 
 
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Contact

 

+44 (0)20 7594 7668r.toumi Website

 
 
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Location

 

H/713Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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126 results found

Arcucci R, Celestino S, Toumi R, Laccetti Get al., 2017, Toward the S3DVAR Data Assimilation Software for the Caspian Sea, International Conference on Numerical Analysis and Applied Mathematics (ICNAAM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

CONFERENCE PAPER

Arcucci R, D'Amore L, Pistoia J, Toumi R, Murli Aet al., 2017, On the variational data assimilation problem solving and sensitivity analysis, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 335, Pages: 311-326, ISSN: 0021-9991

JOURNAL ARTICLE

Arcucci R, D'Amore L, Toumi R, 2017, Preconditioning of the background error covariance matrix in data assimilation for the Caspian Sea, 1st International Conference on Applied Mathematics and Computer Science (ICAMCS), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

CONFERENCE PAPER

Bruneau N, Zika J, Toumi R, 2017, Can the Ocean's Heat Engine Control Horizontal Circulation? Insights From the Caspian Sea, GEOPHYSICAL RESEARCH LETTERS, Vol: 44, Pages: 9893-9900, ISSN: 0094-8276

JOURNAL ARTICLE

Cahill B, Toumi R, Stenchikov G, Osipov S, Brindley Het al., 2017, Evaluation of thermal and dynamic impacts of summer dust aerosols on the Red Sea, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol: 122, Pages: 1325-1346, ISSN: 2169-9275

JOURNAL ARTICLE

Corsaro CM, Toumi R, 2017, A self-weakening mechanism for tropical cyclones, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 143, Pages: 2585-2599, ISSN: 0035-9009

JOURNAL ARTICLE

Li Y, Toumi R, 2017, A balanced Kalman filter ocean data assimilation system with application to the South Australian Sea, OCEAN MODELLING, Vol: 116, Pages: 159-172, ISSN: 1463-5003

JOURNAL ARTICLE

Nissan H, Toumi R, 2017, Regional modelling of rainfall erosivity: sensitivity of soil erosion to aerosol emissions, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 143, Pages: 265-277, ISSN: 0035-9009

JOURNAL ARTICLE

Phillipson L, Toumi R, 2017, Impact of data assimilation on ocean current forecasts in the Angola Basin, OCEAN MODELLING, Vol: 114, Pages: 45-58, ISSN: 1463-5003

JOURNAL ARTICLE

Trivedi A, Toumi R, 2017, Mechanisms of bottom boundary fluxes in a numerical model of the Shetland shelf, OCEAN DYNAMICS, Vol: 67, Pages: 1-21, ISSN: 1616-7341

JOURNAL ARTICLE

Wang S, Toumi R, 2017, A historical analysis of the mature stage of tropical cyclones, International Journal of Climatology, ISSN: 0899-8418

The characteristics of tropical cyclone intensity and size during the mature stage are presented. Rooted in the classic description by Herbert Riehl, the mature stage is identified as the period from the time of lifetime maximum intensity to the time of lifetime maximum size. This study is the first to analyse the global climatology of the mature stage of tropical cyclones in detail. Three basic features at the mature stage are observed: the reduction of intensity, the outward expansion of the eyewall, and the increase of tangential wind in the outer primary circulation. Globally, about a quarter of tropical cyclones undergo the mature stage. High intensity at the end of the immature stage favours the likelihood of the occurrence of the mature stage. The intensity reduction during the mature stage is considerable with nearly three-quarters of cyclones decreasing by more than 10%, which makes the conventional ‘steady-state’ presumption questionable. The increase in the radius of damaging-force wind is typically about 50 km, while the decrease in maximum wind speed is typically 20% at the mature stage. However, the average integrated kinetic energy and hence destructive potential increases substantially by about 70%. This is consistent with our finding that most of the highly damaging landfalling hurricanes undergo a mature stage. Intensity downgrades during the mature stage may be misinterpreted as they are mostly not accompanied by an overall danger reduction.

JOURNAL ARTICLE

Bruneau N, Toumi R, 2016, A fully-coupled atmosphere-ocean-wave model of the Caspian Sea, OCEAN MODELLING, Vol: 107, Pages: 97-111, ISSN: 1463-5003

JOURNAL ARTICLE

Phibbs S, Toumi R, 2016, The dependence of precipitation and its footprint on atmospheric temperature in idealized extratropical cyclones, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, Vol: 121, Pages: 8743-8754, ISSN: 2169-897X

JOURNAL ARTICLE

Poulain V, Bekki S, Marchand M, Chipperfield MP, Khodri M, Lefevre F, Dhomse S, Bodeker GE, Toumi R, De Maziere M, Pommereau J-P, Pazmino A, Goutail F, Plummer D, Rozanov E, Mancini E, Akiyoshi H, Lamarque J-F, Austin Jet al., 2016, Evaluation of the inter-annual variability of stratospheric chemical composition in chemistry-climate models using ground-based multi species time series, JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, Vol: 145, Pages: 61-84, ISSN: 1364-6826

JOURNAL ARTICLE

Wang S, Toumi R, 2016, On the relationship between hurricane cost and the integrated wind profile, Environmental Research Letters, Vol: 11, ISSN: 1748-9326

JOURNAL ARTICLE

Wang S, Toumi R, 2016, On the relationship between hurricane cost and the integrated wind profile, ENVIRONMENTAL RESEARCH LETTERS, Vol: 11, ISSN: 1748-9326

JOURNAL ARTICLE

Wong B, Toumi R, 2016, Model study of the asymmetry in tropical cyclone-induced positive and negative surges, ATMOSPHERIC SCIENCE LETTERS, Vol: 17, Pages: 334-338, ISSN: 1530-261X

JOURNAL ARTICLE

Wong B, Toumi R, 2016, Effect of extreme ocean precipitation on sea surface elevation and storm surges, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 142, Pages: 2541-2550, ISSN: 0035-9009

JOURNAL ARTICLE

Bossay S, Bekki S, Marchand M, Poulain V, Toumi Ret al., 2015, Sensitivity of tropical stratospheric ozone to rotational UV variations estimated from UARS and Aura MLS observations during the declining phases of solar cycles 22 and 23, Journal of Atmospheric and Solar-Terrestrial Physics, Vol: 130-131, Pages: 96-111, ISSN: 1364-6826

The correlation between tropical stratospheric ozone and UV radiation on solar rotational time scales is investigated using daily satellite ozone observations and reconstructed solar spectra. We consider two 3-year periods falling within the descending phases of two 11-year solar cycles 22 (1991-1994) and 23 (2004-2007). The UV rotational cycle is highly irregular and even disappears for half a year during cycle 23. For the 1991-1994 period, ozone and 205 nm UV flux are found to be correlated between about 10 and 1 hPa with a maximum of 0.29 at ~5 hPa; ozone sensitivity (percentage change in ozone for 1 percent change in UV) peaks at ~0.4. Correlation during cycle 23 is weaker with a peak ozone sensitivity of 0.2. The correlation is found to vary widely, not only with altitude, but also from one year to the next with a rotational signal in ozone appearing almost intermittent. Unexpectedly, the correlation is not found to bear any relation with the solar rotational forcing. For instance, solar rotational fluctuations are by far the strongest during 1991-1992 whereas the correlation peaks at the end of 1993, a rotationally quiescent period. When calculated over sliding intervals of 1-year, the sensitivity is found to vary very strongly within both 3-year periods; it is almost negligible over the entire vertical profile during some 1-year intervals or reaches close to 1 around 2-5 mb for other intervals. Other sources of variability, presumably of dynamical origin, operate on the rotational spectral range and determine to a large extent the estimated solar rotational signal. Even considering 3 years of observations (corresponding to about 40 solar cycles), the extraction of the rotational solar signal does not appear to be robust during declining phases of 11-year solar cycles. As observational studies cover at best three 11-year solar cycles, it must be challenging to produce a reliable estimation of the 11-year solar cycle signal in stratospheric ozone, especially in

JOURNAL ARTICLE

Broadbridge MB, Toumi R, 2015, The deep circulation of the Faroe-Shetland Channel: Opposing flows and topographic eddies, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol: 120, Pages: 5983-5996, ISSN: 2169-9275

JOURNAL ARTICLE

Hardwick SR, Toumi R, Pfeifer M, Turner EC, Nilus R, Ewers RMet al., 2015, The relationship between leaf area index and microclimate in tropical forest and oil palm plantation: Forest disturbance drives changes in microclimate, AGRICULTURAL AND FOREST METEOROLOGY, Vol: 201, Pages: 187-195, ISSN: 0168-1923

JOURNAL ARTICLE

Newinger C, Toumi R, 2015, Potential impact of the colored Amazon and Orinoco plume on tropical cyclone intensity, Journal of Geophysical Research: Oceans, Vol: 120, Pages: 1296-1317, ISSN: 2169-9275

JOURNAL ARTICLE

Nicholls JF, Toumi R, Stenchikov G, 2015, Effects of unsteady mountain-gap winds on eddies in the Red Sea, ATMOSPHERIC SCIENCE LETTERS, Vol: 16, Pages: 279-284, ISSN: 1530-261X

JOURNAL ARTICLE

Sparks N, Toumi R, 2015, Numerical Simulations of Daytime Temperature and Humidity Crossover Effects in London, BOUNDARY-LAYER METEOROLOGY, Vol: 154, Pages: 101-117, ISSN: 0006-8314

JOURNAL ARTICLE

Tamura-Wicks H, Toumi R, Budgell WP, 2015, Sensitivity of Caspian sea-ice to air temperature, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 141, Pages: 3088-3096, ISSN: 0035-9009

JOURNAL ARTICLE

Wang S, Toumi R, Czaja A, Van Kan Aet al., 2015, An analytic model of tropical cyclone wind profiles, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 141, Pages: 3018-3029, ISSN: 0035-9009

JOURNAL ARTICLE

Nicholls JF, Toumi R, 2014, On the lake effects of the Caspian Sea, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 140, Pages: 1399-1408, ISSN: 0035-9009

JOURNAL ARTICLE

Phibbs S, Toumi R, 2014, Modeled dependence of wind and waves on ocean temperature in tropical cyclones, GEOPHYSICAL RESEARCH LETTERS, Vol: 41, Pages: 7383-7390, ISSN: 0094-8276

JOURNAL ARTICLE

Radu R, Toumi R, Phau J, 2014, Influence of atmospheric and sea surface temperature on the size of hurricane Catarina, QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Vol: 140, Pages: 1778-1784, ISSN: 0035-9009

JOURNAL ARTICLE

White RH, Toumi R, 2014, River flow and ocean temperatures: The Congo River, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol: 119, Pages: 2501-2517, ISSN: 2169-9275

JOURNAL ARTICLE

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