-> http://www.agu.org/pubs/crossref/2012/2012GL051000.shtml wetenschappelijk artikel (alleen abstract)
Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.
-> volgens dit verhaal vooral in de herfst en winter, dus wellicht geen goede verklaring voor de zomer?
-> klopt het verhaal van de Europese moesson wel, ons weer komt toch uit het westen? Of beter gezegd uit de tropen.
Nog meer uitleg:
http://thinkprogress.org/climate/2012/04/04/457823/arctic-warming-extreme-weather-events-drought-flooding-cold-spells-and-heat-waves/?mobile=nc
Presentatie vd auteurs
http://conference2011.wcrp-climate.org/posters/C11/C11_Francis_M123B.pdf
Conclusies:
Based on these results for N. America, as well as similar analyses for other regions not shown here, we conclude:
Arctic Amplification leads to weaker zonal flow in upper levels, particularly in fall and winter and also to a higher-amplitude pattern in all seasons.
Figure 8 shows that the number of gridpoints with 500 hPa heights representative of the maximum flow has increased north of 60oN (top panels), suggesting that the peaks of ridges have shifted northward, while the number of points south of 40oN has decreased, suggesting the entire jet stream has shifted northward. This is consistent with other studies (e.g., Seidel et al, 2007) suggesting that the tropics are expanding as a result of global warming.
Ridges are shifting northward faster, however, as indicated by increasing standard deviations (Fig. 8, lower panels) and as illustrated in schematic to left.
Waves in 500 hPa heights have elongated and the flow has amplified, favoring more persistent weather conditions
Weaker zonal flow further enhances wave amplitude, just as a river flowing down a steep slope tends to flow straighter than one on a flat coastal plain (photos left).
Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.
-> volgens dit verhaal vooral in de herfst en winter, dus wellicht geen goede verklaring voor de zomer?
-> klopt het verhaal van de Europese moesson wel, ons weer komt toch uit het westen? Of beter gezegd uit de tropen.
Nog meer uitleg:
http://thinkprogress.org/climate/2012/04/04/457823/arctic-warming-extreme-weather-events-drought-flooding-cold-spells-and-heat-waves/?mobile=nc
Presentatie vd auteurs
http://conference2011.wcrp-climate.org/posters/C11/C11_Francis_M123B.pdf
Conclusies:
Based on these results for N. America, as well as similar analyses for other regions not shown here, we conclude:
Arctic Amplification leads to weaker zonal flow in upper levels, particularly in fall and winter and also to a higher-amplitude pattern in all seasons.
Figure 8 shows that the number of gridpoints with 500 hPa heights representative of the maximum flow has increased north of 60oN (top panels), suggesting that the peaks of ridges have shifted northward, while the number of points south of 40oN has decreased, suggesting the entire jet stream has shifted northward. This is consistent with other studies (e.g., Seidel et al, 2007) suggesting that the tropics are expanding as a result of global warming.
Ridges are shifting northward faster, however, as indicated by increasing standard deviations (Fig. 8, lower panels) and as illustrated in schematic to left.
Waves in 500 hPa heights have elongated and the flow has amplified, favoring more persistent weather conditions
Weaker zonal flow further enhances wave amplitude, just as a river flowing down a steep slope tends to flow straighter than one on a flat coastal plain (photos left).
Bericht laatst bijgewerkt: 27-06-2012 18:17
„Et nul ne se connait tant qu'il n'a pas souffert, „C'est une dure loi, mais une loi suprème, „Vieille comme le monde et la fatalité, „Qu'l nous faut du malheur regevoir le baptéme, ~Et qu'a ce triste prix tout doit étre acheté. „Les moissons pour murir out besoin de rosée, „Pour vivre et pour sentir l'homme a besoin de pleura, „La joie a pour symbole une plante brisée, „Humide encore de pluie et couverte de fleurs."
:).
.
:D