Featured Research

from universities, journals, and other organizations

More summer heatwaves likely in Europe: Predictability of European summer heat from spring and winter rainfall

Date:
May 27, 2012
Source:
ETH Zürich
Summary:
The prediction, one season ahead, of summer heat waves in Europe remains a challenge. A new study shows that summer heat in Europe rarely develops after rainy winter and spring seasons over Southern Europe. Conversely dry seasons are either followed by hot or cold summers. The predictability of summer heat is therefore asymmetric. Climate projections indicate a drying of Southern Europe. The study suggests that this asymmetry should create a favorable situation for the development of more summer heat waves with however a modified seasonal predictability from winter and spring rainfall.

The prediction, one season ahead, of summer heat waves in Europe remains a challenge. A new study led by a French-Swiss team shows that summer heat in Europe rarely develops after rainy winter and spring seasons over Southern Europe. Conversely dry seasons are either followed by hot or cold summers. The predictability of summer heat is therefore asymmetric. Climate projections indicate a drying of Southern Europe. The study suggests that this asymmetry should create a favorable situation for the development of more summer heat waves with however a modified seasonal predictability from winter and spring rainfall.

These results will be published online in Nature Climate Change, on 27th May 2012.

Along the past decade, Europe witnessed a series of exceptional summer heat waves with important impacts on society (eg. the 2003 and 2010 heat waves). These extreme cases are often considered as prototypes of summers of future warmer climate. Our ability to anticipate such events one or several months in advance remains poor. A study lead by the Laboratoire des Sciences du Climat et de l'Environnement (LSCE) and the Swiss Federal Institute of Technology Zurich (ETH Zurich), published in Nature Climate Change, examines whether preceding seasons rainfall allow to predict the frequency of forthcoming summer hot days [1] and physical causes of such a predictability.

From the analysis of precipitation and temperature observations from 200 European meteorological stations over more than 60 years, this study generalizes a result obtained over a region of Southeastern Europe [2]: rainy winters and springs inhibit the development of hot summer days in the following summer season, while dry or normal rainfalls allow either a large or a weak number of hot temperature days. Precipitation events driving this predictability property for Western/Central Europe are exclusively those located over Southern Europe in preceding months. The study shows that this asymmetric predictability results from a difference in the sensitivity of hot days frequency to atmospheric circulation: after dry months, a strong solar energy, associated with anticyclonic conditions, is transferred to the atmosphere through heat fluxes, amplifying drought and heat with a positive feedback. After rainy months, solar energy is largely used for evapo-transpiration instead, limiting the amplification of heat. Even after very dry winter and spring seasons, early summer heavy precipitations can annihilate the potential to develop extreme temperatures, which may have been the case during the 2011 summer, which followed an exceptional spring drought.

The study then analyses the ability of 14 global climate models, used in future climate projections, to reproduce the asymmetric relationship between precipitation and temperature found in the observations. Most models (among which the most recent version of Institut-Pierre Simon Laplace climate model) do exhibit these relations, but with less clear links. Models that best fit the observed relations predict summer temperatures and winter and springs dryness [3] in the upper part of the range of the uncertainty.

[1] Days for which mean temperature lies within the upper 10% of temperature values

[2] Hirschi, M. et al. Observational evidence for soil-moisture impact on hot extremes in southeastern Europe. Nature Geosciences 4, 17-21 (2011).

[3] See also : Seneviratne, S.I., et al., 2012: Changes in climate extremes and their impacts on the natural physical environment. In: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (IPCC SREX report) [Field, C.B., V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.-K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley (eds.)]


Story Source:

The above story is based on materials provided by ETH Zürich. Note: Materials may be edited for content and length.


Journal Reference:

  1. Benjamin Quesada, Robert Vautard, Pascal Yiou, Martin Hirschi, Sonia I. Seneviratne. Asymmetric European summer heat predictability from wet and dry southern winters and springs. Nature Climate Change, 2012; DOI: 10.1038/nclimate1536

Cite This Page:

ETH Zürich. "More summer heatwaves likely in Europe: Predictability of European summer heat from spring and winter rainfall." ScienceDaily. ScienceDaily, 27 May 2012. <www.sciencedaily.com/releases/2012/05/120527153720.htm>.
ETH Zürich. (2012, May 27). More summer heatwaves likely in Europe: Predictability of European summer heat from spring and winter rainfall. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2012/05/120527153720.htm
ETH Zürich. "More summer heatwaves likely in Europe: Predictability of European summer heat from spring and winter rainfall." ScienceDaily. www.sciencedaily.com/releases/2012/05/120527153720.htm (accessed September 20, 2014).

Share This



More Earth & Climate News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) — An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) — Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) — Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) — A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins