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102 results on '"Kew, Sarah"'

101. IMILAST.

Author

NEU, URS, AKPEROV, MIRSEID G., BELLENBAUM, NINA, BENESTAD, RASMUS, BLENDER, RICHARD, CABALLERO, RODRIGO, COCOZZA, ANGELA, DACRE, HELEN F., YANG FENG, FRAEDRICH, KLAUS, GRIEGER, JENS, GULEV, SERGEY, HANLEY, JOHN, HEWSON, TIM, INATSU, MASARU, KEAY, KEVIN, KEW, SARAH F., KINDEM, INA, LECKEBUSCH, GREGOR C., and LIBERATO, MARGARIDA L. R.

Subjects
TROPICAL cyclones, GEOPHYSICAL prediction, WEATHER forecasting, OCEANOGRAPHY, METEOROLOGY
Abstract

The variability of results from different automated methods of detection and tracking of extra-tropical cyclones is assessed in order to identify uncertainties related to the choice of method. Fifteen international teams applied their own algorithms to the same dataset--the period 1989-2009 of interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) data. This experiment is part of the community project Intercomparison of Mid Latitude Storm Diagnostics (IMILAST; see www.proclim.ch/imilast/index.html). The spread of results for cyclone frequency, intensity, life cycle, and track location is presented to illustrate the impact of using different methods. Globally, methods agree well for geographical distribution in large oceanic regions, interannual variability of cyclone numbers, geographical patterns of strong trends, and distribution shape for many life cycle characteristics. In contrast, the largest disparities exist for the total numbers of cyclones, the detection of weak cyclones, and distribution in some densely populated regions. Consistency between methods is better for strong cyclones than for shallow ones. Two case studies of relatively large, intense cyclones reveal that the identification of the most intense part of the life cycle of these events is robust between methods, but considerable differences exist during the development and the dissolution phases. [ABSTRACT FROM AUTHOR]

Published
2013
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102. Are Greenhouse Gas Signals of Northern Hemisphere winter extra-tropical cyclone activity dependent on the identification and tracking algorithm?

Author

Ulbrich, Uwe, Leckebusch, Gregor C., Grieger, Jens, Schuster, Mareike, Akperov, Mirseid, Bardin, Mikhail Yu., Feng, Yang, Gulev, Sergey, Inatsu, Masaru, Keay, Kevin, Kew, Sarah F., Liberato, Margarida L.R., Lionello, Piero, Mokhov, Igor I., Neu, Urs, Pinto, Joaquim G., Raible, Christoph C., Reale, Marco, Rudeva, Irina, Simmonds, Ian, Tilinina, Natalia D., Trigo, Isabel F., Ulbrich, Sven, and Wang

Abstract

For Northern Hemisphere extra-tropical cyclone activity, the dependency of a potential anthropogenic climate change signal on the identification method applied is analysed. This study investigates the impact of the used algorithm on the changing signal, not the robustness of the climate change signal itself. Using one single transient AOGCM simulation as standard input for eleven state-of-the-art identification methods, the patterns of model simulated present day climatologies are found to be close to those computed from re-analysis, independent of the method applied. Although differences in the total number of cyclones identified exist, the climate change signals (IPCC SRES A1B) in the model run considered are largely similar between methods for all cyclones. Taking into account all tracks, decreasing numbers are found in the Mediterranean, the Arctic in the Barents and Greenland Seas, the mid-latitude Pacific and North America. Changing patterns are even more similar, if only the most severe systems are considered: the methods reveal a coherent statistically significant increase in frequency over the eastern North Atlantic and North Pacific. We found that the differences between the methods considered are largely due to the different role of weaker systems in the specific methods.

Published
2013
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