Sentences with phrase «poleward shifts in»

Melting Arctic ice - sheets will reduce ocean salinities (IPCC, 2001), causing species - specific shifts in the distribution and biomass of major constituents of Arctic food webs, including poleward shifts in communities and the potential loss of some polar species (such as the narwhal, Monodon monoceros).

It is no surprise therefore that coastal marine species have shown some of the fastest responses to climate change in any system, with species - specific responses to thermal stress causing poleward shifts in biogeographic distributions towards cooler environments, as well as changes in phenology and regime shifts.

Poleward shifts in geographical ranges of butterfly species associated with regional warming.

Direct effects of increasing temperature on marine and freshwater ecosystems are already evident, with rapid poleward shifts in regions, such as the north - east Atlantic, where temperature change has been rapid (see Chapter 1).

Landmark studies included Parmesan (1996), finding a latitude shift attributed to climate change in a North American butterfly (Edith's Checkerspot, photo (c) 2004 Jeffrey Pippen, by permission), and Parmesan et al. (1999) with «the first large - scale evidence of poleward shifts in entire species» ranges» from Europe.

There are also poleward shifts in the vast atmospheric patterns that control where rain falls.

Other aspects of global warming's broad footprint on the world's ecosystems include changes in the abundance of more than 80 percent of the thousands of species included in population studies; major poleward shifts in living ranges as warm regions become hot, and cold regions become warmer; major increases (in the south) and decreases (in the north) of the abundance of plankton, which forms the critical base of the ocean's food chain; the transformation of previously innocuous insect species like the Aspen leaf miner into pests that have damaged millions of acres of forest; and an increase in the range and abundance of human pathogens like the cholera - causing bacteria Vibrio, the mosquito - borne dengue virus, and the ticks that carry Lyme disease - causing bacteria.

Meanwhile, increasing temperature and ocean warming may lead to the reduction of diatom production as well as cell size, inducing poleward shifts in the biogeographic distribution of diatoms.

Climate changes that began ~ 17,700 years ago included a sudden poleward shift in westerly winds encircling Antarctica with corresponding changes in sea ice extent, ocean circulation, and ventilation of the deep ocean.

The tropical pipe becomes significantly more leaky, and greater transport into the lowermost stratosphere in the subtropics appears to be occurring, possibly in conjunction with a poleward shift in wave energy convergences.

The paper's introduction has one sentence on the observational evidence for a poleward shift in storm tracks reported in earlier papers (McCabe et al. 2001; Fyfe 2003).

For example, one of the clearest predicted ecological impacts of climate is a poleward shift in the ranges of plant and animal species.

There has been a poleward shift and intensification of the mid-latitude depressions in the North Atlantic from the 1950s to the early 2000s, which is linked to a poleward shift in Northern Hemisphere jet streams.

Observational and numerical evidence of a poleward shift in the Southern Hemisphere middle latitude jetstream (a positive trend in the Southern Annular mode) in response to Antarctic ozone depletion (Gillett and Thompson, 2003; Arblaster and Meehl, 2006; Son et al., 2010; Polvani et al., 2011; McLandress et al., 2011; Thompson et al., 2011).

Not exact matches

At the same time, poleward shifts of westerly winds in the Southern Ocean reduced the region's ability to suck up CO2 as have mid-latitude droughts, which slowed the growth rate of forests and plants that capture carbon.

Those patterns matched three rather dire climate model predictions: that storm tracks — the paths along which cyclones travel in the Northern and Southern hemispheres — would shift poleward; that subtropical dry regions would expand, and that the tops of the highest clouds would get even higher.

«We estimate that the jet streams in both hemispheres have shifted poleward by roughly 1 degree latitude in both summer and winter seasons,» the researchers, led by Qiang Fu of the University of Washington, write in today's Science.

For example, the Gulf of Mexico has an east - west coastline that prevents a northerly or poleward shift of species in response to warming ocean waters,.

This study found that associated with a poleward shift of the subtropical jet in the North Pacific basin, the number of atmospheric river days increases much more significantly in Alaska during spring because both increased moisture and increased wind speed gang up to increase the frequency of atmospheric rivers.

Despite large year - to - year variability of temperature, decadal averages reveal isotherms (lines of a given average temperature) moving poleward at a typical rate of the order of 100 km / decade in the past three decades [101], although the range shifts for specific species follow more complex patterns [102].

Both processes act to tighten the relation between subpolar surface heat flux variability and MOC - variability, resulting in a poleward shift of the latter.

Here we are talking about modification of atmospheric circulation — poleward expansion of the dry, descending portion of the Hadley Cell circulation by a few degrees, associated shifts in the jet stream.

Indeed that poleward shift was supposed to be accompanied by a tropospheric hot spot as the enhanced upward energy flux was then constrained by extra GHGs so that the «surplus» energy was retained in the troposphere and thereby denied to the stratosphere which then cooled as per observations and despite the «normal» warming of the stratosphere that would otherwise have been expected from the highly active sun at the time.

The authors find that, globally, the latitudes of maximum intensity have shifted poleward, 53 kilometres per decade in the Northern Hemisphere and 62 kilometres per decade in the Southern Hemisphere.

Current work1 has provided evidence of the increase in frequency and intensity of winter storms, with the storm tracks shifting poleward, 2,3 but some areas have experienced a decrease in winter storm frequency.4 Although there are some indications of increased blocking (a large - scale pressure pattern with little or no movement) of the wintertime circulation of the Northern Hemisphere, 5 the assessment and attribution of trends in blocking remain an active research area.6 Some recent research has provided insight into the connection of global warming to tornadoes and severe thunderstorms.7, 8

Model projections indicate that the Hadley Circulation will shift its downward branch poleward in both the Northern and Southern Hemispheres, causing drying as a result.

However, Yin (2005) studied the poleward shift of storm tracks PROJECTED to occur in the 21st century and contains no observational data.

So the emphasis shifted to poleward shift of climate zones with particular emphasis on rain and desert belts moving such that agriculture is disrupted by great changes in precipitation patterns.

Ozone depletion in the late twentieth century was the primary driver of the observed poleward shift of the jet during summer, which has been linked to changes in tropospheric and surface temperatures, clouds and cloud radiative effects, and precipitation at both middle and low latitudes.

According to the report, some of the small mammals have recently acquired new parasites, indicating poleward shifts of sub-Arctic faunas and increases in biodiversity.

This shift is correlated with a poleward shift of the jet stream in the inter-model spread (R = 0.56).

We found that the two quantities that correlate significantly and consistently in all ocean basins and seasons are the Hadley cell extent and the high cloud field: when the Hadley cell edge moves poleward, the high cloud field also shifts towards the poles, and vice versa.

Despite large year - to - year variability of temperature, decadal averages reveal isotherms (lines of a given average temperature) moving poleward at a typical rate of the order of 100 km / decade in the past three decades [101], although the range shifts for specific species follow more complex patterns [102].

What they discovered was that the poleward shift of the clouds, which occurs in both the Northern and Southern Hemispheres, connected more strongly with the expansion of the tropics, defined by the general circulation Hadley cell, than with the movement of the jets.

If the surface pressure distribution begins to shift to a more meridional / equatorward pattern as it did around 2000 then if previously it was in a poleward / zonal mode it is clear that warming will have ceased and cooling has begun due to more global cloudiness and less solar energy getting into the oceans.

This is associated with a poleward shift of the westerlies at the surface (see Section 10.3.6) and in the upper troposphere particularly notable in the Southern Hemisphere (SH)(Stone and Fyfe, 2005), and increased relative angular momentum from stronger westerlies (Räisänen, 2003) and westerly momentum flux in the lower stratosphere particularly in the tropics and southern mid-latitudes (Watanabe et al., 2005).

A poleward shift of the Hadley circulation by 5 degrees in two decades is not climate change?

The large scale atmospheric circulation «cells» shift polewards in warmer periods (for example, interglacials compared to glacials), but remain largely constant as they are, fundamentally, a property of the Earth's size, rotation rate, heating and atmospheric depth, all of which change little.

Bender, F. A. - M., Ramanathan, V. & Tselioudis, G. Changes in extratropical storm track cloudiness 1983 — 2008: observational support for a poleward shift.

The ozone hole indirect effect: cloud - radiative anomalies accompanying the poleward shift of the eddy - driven jet in the Southern Hemisphere.

The poleward shift of the Southern Hemisphere middle latitude jetstream in response to increasing carbon dioxide is one of the most robust circulation responses found in climate change experiments, and is predicted to occur during all seasons (IPCC, 2007c).

The air circulation systems move latitudinally poleward or equatorward depending on whether there is net cooling or warming of the air at a gradual if variable rate all the time and climate shifts in any given location depend mainly on the changing position of that location in relation to the latitudinal position of the major air circulation systems.

In particular, the forced poleward shift of the storm tracks is most significant over the North Atlantic, which highlights the importance of a regional perspective when considering Hadley Cell width variations.

The thing is that as regards the sequence of observed events leading to changes in tropospheric temperature trends and the cyclical poleward and equatorward shifts in the air circulation systems the NCM is pretty robust.

NSF - funded scientists believe at least part of the answer lies in the frozen tundras of Siberia, where greater - than - average autumn snowfall causes weather patterns in the Arctic regions to shift southward into the midlatitudes during the winter, while less - than - average snowfall causes the patterns to retreat poleward.

We found that relative to the global - mean trends of the respective layers, both hemispheres have experienced enhanced tropospheric warming and stratospheric cooling in the 15 to 45 ° latitude belt, which is a pattern indicative of a widening of the tropical circulation and a poleward shift of the tropospheric jet streams and their associated subtropical dry zones.

I first noticed an increase in meridionality and a reversal of the earlier poleward shift as long ago as 2000.

While the upper - troposphere tropical warming induces a poleward shift of the jet in winter, Arctic Amplification and a weaker stratospheric polar vortex result in the opposite effect.