Sentences with phrase «circulation trends over»

While we have not evaluated all of the feedback mechanisms and internal and external forcing factors involved, we have shown evidence that the West Antarctic warming is consistent with the regional decline of sea ice in the ABS and with the atmospheric circulation trends over the Southern Oceans.

This is important in that the atmospheric circulation trends over the Antarctic vary substantially by season, with summer and autumn exhibiting decreases in sea level pressure over the circumpolar trough and over the continent.

Regardless of the exact reasons for differences in the TOGA and GOGA experiments, the model results support the notion that SSTs in the tropics to subtropics have played a role in forcing the atmospheric circulation trends over the SH in austral spring.

Not exact matches

Our general circulation model simulations, which take into account the recently observed widespread occurrence of vertically extended atmospheric brown clouds over the Indian Ocean and Asia3, suggest that atmospheric brown clouds contribute as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends.

An INTAS - funded research project has been initiated to study the possible trends in snow cover during the last century over Northern Eurasia and the relation between snow cover variability and variations in atmospheric circulation patterns.

As noted above, most earlier hindcasts of 20th century climate as well as current IPCC AR4 runs [Miller et al., 2006; Knutson et al., 2006] do not reproduce the observed trends over recent decades in the AO component of the circulation, and thus do not capture the intensification of warming trends that has been observed over Northern Europe and Asia.

Our general circulation model simulations, which take into account the recently observed widespread occurrence of vertically extended atmospheric brown clouds over the Indian Ocean and Asia, suggest that atmospheric brown clouds contribute as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends.

LTP / ocean upwelling can generate low - frequency anomalies that look like increasing trends over very short (relative to ocean circulation) time scales.

For the entire Northern Hemisphere, there is evidence of an increase in both storm frequency and intensity during the cold season since 1950,1 with storm tracks having shifted slightly towards the poles.2, 3 Extremely heavy snowstorms increased in number during the last century in northern and eastern parts of the United States, but have been less frequent since 2000.11,15 Total seasonal snowfall has generally decreased in southern and some western areas, 16 increased in the northern Great Plains and Great Lakes region, 16,17 and not changed in other areas, such as the Sierra Nevada, although snow is melting earlier in the year and more precipitation is falling as rain versus snow.18 Very snowy winters have generally been decreasing in frequency in most regions over the last 10 to 20 years, although the Northeast has been seeing a normal number of such winters.19 Heavier - than - normal snowfalls recently observed in the Midwest and Northeast U.S. in some years, with little snow in other years, are consistent with indications of increased blocking (a large scale pressure pattern with little or no movement) of the wintertime circulation of the Northern Hemisphere.5 However, conclusions about trends in blocking have been found to depend on the method of analysis, 6 so the assessment and attribution of trends in blocking remains an active research area.

«To conclude, modeled atmospheric circulation and SST trends over the past century are significantly different from the observed ones.

However, the opposing circulation trends have a smaller impact on the range of SAT and P trends due to the fact that the radiatively - forced response is greater over the longer (50 - year) time horizon.

This study has highlighted the role of internal variability of the NAO, the leading mode of atmospheric circulation variability over the Atlantic / European sector, on winter (December - March) surface air temperature (SAT) and precipitation (P) trends over the next 30 years (and the next 50 years: see Supplemental Materials) using a new 40 - member ensemble of climate change simulations with CESM1.

Therefore, we suggest that a significant portion of the wintertime temperature trend is driven by dynamical interactions between October Eurasian snow cover, which has increased over the last two decades, and the large - scale NH extratropical circulation in the late autumn and winter.

The Samanta paper does not directly address the first point; this is addressed using global circulation models (of which some, but not all, show a strong drying trend for the east of the Amazon over the 21st century).