Naslov
An ensemble analysis of model climate response to tropical Pacific SST anomalies

Autori
Herceg Bulić, Ivana ; Branković, Čedo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
EMS Annual Meeting Abstracts, Volume 2, 2005 / - , 2005

Skup
5th Annual Meeting of the European Meteorological Society/7th European Conference on Applications of Meteorology 2005

Mjesto i datum
Utrecht, Nizozemska, 12.09.2005. - 16.09.2005

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
ensemble analysis; model climate response; tropical Pacific SST anomalies; ENSO signal

Sažetak
The JFM climate response of the Northern Hemisphere atmosphere to the observed tropical SST anomalies for the 1855-2002 period is analysed from the 35-member ensemble made with Speedy, an AGCM of intermediate complexity. The model was run at the T30-L8 resolution, and initial conditions and the early stage of model runs differ among ensemble members in the definition of tropical diabatic heating. The SST anomalies in the Nino3.4 region were categorised into the seven classes extending from strong cold to strong warm ENSO events. This enables a composite analysis of the influence of the tropical Pacific SST on the Northern Hemisphere atmospheric circulation with a special consideration for the European/Atlantic region. As expected, the strongest signal was detected over the PNA region ; however, an 'asymmetry' in the model response was found with a stronger signal corresponding to the warm ENSO and somewhat weaker signal for the cold ENSO. Over Europe, the model climate response is generally much weaker than that over the PNA region ; however, a noticeable impact was found for strong ENSO composite. The potential seasonal predictability is measured as the ratio of seasonally averaged SST-forced signal and internally generated seasonal mean noise. For geopotential height, the largest signal-to-noise ratio was found in the Tropics, especially for the strong warm composite. The PNA climate is found to be most predictable for warm events. Although the ENSO signal was also found over Europe, the seasonal predictability is mostly very weak there.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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