When the Arctic warmed after the ice age 10,000 years ago, it created perfect conditions for drought. According to new research led by Bryan Shuman, a professor in the Department of Geology and Geophysics at the University of Wyoming, similar changes could be in store today because a warming Arctic weakens the temperature difference between the tropics and the poles. This, in turn, results in less precipitation and weaker mid-latitude westerly wind flow leading to prolonged drought. When the temperature difference between the tropics and the poles are wider, the result is more precipitation, intense cyclones and more robust wind flow. However, due to the Arctic ice melting and warming up the poles, those disparate temperatures are becoming closer.
In this study, the author takes a global approach and relates the history of severe dry periods of temperature changes. Importantly, when temperatures have changed in similar ways to today (warming of the Arctic), the mid-latitudes, particularly places like Wyoming and other parts of central North America have dried out. Climate models anticipate similar changes in the future.
Currently, the northern high latitudes are warming at rates that are double the global average. This will decrease the equator-to-pole temperature gradient to values comparable with the early to middle Holocene Period. According to the paper, geological evidence helped to estimate how dry conditions have been in the past 10,000 years. Lakes are these natural recorders of wet and dry conditions and when lakes rise or lower, they leave geological evidence behind. The researchers' Holocene temperature analysis included 236 records from 219 sites. During the past 10,000 years, many of the lakes studied were lower earlier in history than today.
The research group looked at the evolution of the tropic-to-pole temperature difference from three time periods: 100 years ago, 2,000 years ago and 10,000 years ago. For the last 100 years, many atmospheric records facilitated the analysis but, for the past 2,000 years or 10,000 years, there were fewer records available. Tree rings can help to expand studies to measure temperatures over the past 2,000 years, but lake deposits, cave deposits and glacier ice were studied to record prior temperatures and precipitation. According to the study, geological evidence provides an excellent test to validate computer models that make forecast for some other time period.
Cody C. Routson, Nicholas P. McKay, Darrell S. Kaufman, Michael P. Erb, Hugues Goosse, Bryan N. Shuman, Jessica R. Rodysill, Toby Ault. Mid-latitude net precipitation decreased with Arctic warming during the Holocene. Nature, 2019; DOI:10.1038/s41586-019-1060-3
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© 2019 Oceanographer Daneeja Mawren
DISCUSSION: There is no question that within the last 7 to 10 days, millions and millions of people across a substantial portion of North America experienced the full force of the atmospheric larger-scale circulation which is known as the Polar Vortex. Despite the large variety of ways in which various media platforms have continued to discuss and try to explain the presence as well as the impacts of the Polar Vortex, it is imperative to fully break down what the Polar Vortex is and how scientists physically study its structure and its corresponding impacts.
To start, the Polar Vortex is most fundamentally a larger-scale stratospheric circulation (i.e., an atmospheric circulation located within the layer of the atmosphere which is positioned directly above the troposphere which is where the majority of the Earth’s weather occurs) which somewhat oscillates in its position in the Arctic and Antarctic regions during the course of the Winter-time months in the respective hemispheres. During a given Winter-time season, there are stronger Arctic low-pressure systems which periodically develop over the Arctic and Antarctic regions of the world. As these powerful low-pressure systems develop and sometimes persist, such systems can often help to trap very cold air in and around the Arctic and/or Antarctic regions. However, when these powerful upper-level circulations occasionally become weaker and increasingly more unstable under the right circumstances, this can quickly lead to situations defined by the release of severe cold air intrusions into many parts of North America, Europe and beyond.
Attached above is a neat graphic and an exact excerpt which was produced and written by the National Oceanic and Atmospheric Administration (NOAA) which perfectly encapsulates the general physics and dynamics of the Polar Vortex in both the Northern and Southern Hemisphere. “The polar vortex is a large area of low pressure and cold air surrounding the Earth's North and South poles. The term vortex refers to the counter-clockwise flow of air that helps keep the colder air close to the poles (left globe). Often during winter in the Northern Hemisphere, the polar vortex will become less stable and expand, sending cold Arctic air southward over the United States with the jet stream (right globe).” You will also notice how the episodic descent of colder air masses into the mid-latitudes (i.e., where most of the world’s population lives) is often contingent on regional and larger-scale fluctuations with respect to both temperature and pressure regimes.
Attached right above within the embedded Tweet courtesy of Mathew Barlow, you can see how the recent behavior and overall evolution of the Polar Vortex circulation was incredibly fluid and very dynamic in nature. Moreover, you can see how when the Polar Vortex circulation finally broke up and pivoted around each other via the “Fujiwara Effect” which can be found in other recent articles which have been posted to our website in recent days (and can also be found through the search tab on the home page of our website), there was still a good portion of the circulation which remained entrenched up within the outer limits of northern Canada and the Arctic Circle. Thus, even as severely cold as it ended up getting within the past 7 to 10 days across the north-central and northeastern United States, there were still other “pieces of the puzzle” which never quite made it down into the United States which is good news despite how frigid it still was for a solid 3 to 4-day period not too long ago.
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© 2019 Meteorologist Jordan Rabinowitz
DISCUSSION: Without any doubts, many parts of the contiguous United States have already been “under the gun” with round after round of cold, breezy conditions coming through again and again. Even though we are only in mid-November now, there is no debate that the atmosphere does not always take into full consideration and observe the typical climatology in the context of global air mass regimes according to both latitudinal and longitudinal locations. Many people living across parts of the contiguous United States and across a good portion of central and northern Europe are often very much aware of the fact that Winter weather can strike well before and well after the official start of meteorological Winter. As we head into late November and early December, there is little to no debate that this will very much be the case in the context of an earlier onset of more intense Winter conditions.
This earlier onset of more intense Winter conditions across a good portion of the United States and Europe can be reflected by the tweet which is attached above (courtesy of “@WeatherintheHud” from Twitter), there a number of larger scale features which are scientifically referred to as “Rossby Waves” propagating across the Northern Hemisphere. Rossby waves are effectively larger-scale perturbations in global atmospheric flow which help to transfer heat, moisture, and momentum to different parts of planet Earth at a given point in time. Depending on the number of Rossby waves which are present during a given period, there can sometimes be variable amounts of storminess induced by the progression of successive Rossby waves (or what is also sometimes referred to as a “Rossby wave train”) over a given region over some period. Thus, in looking to the tweet attached above, there is absolutely no debate that there is a heck of a lot of Rossby waves progressing across the larger extent of the Northern Hemisphere at the present time.
As a result of the increased Rossby wave activity, there is an increased concern that the increased prevalence of more frequent larger-scale atmospheric perturbations will more than likely lead to a substantial increase in the degree of Winter storm potential across a good portion of the lower 48 portion of the United States and across much of Europe as well. Thus, it goes without saying that the transition from Fall-time to Winter-time is certainly well underway and there it quite a good chunk of surprises on the way for many millions of people around the world in the coming days and weeks. That is, if things remain on the course they are currently on in the atmosphere across the Northern Hemisphere. As always, please stay tuned for updates on current and future high-impact weather events by visiting the Global Weather and Climate Center.
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© 2018 Meteorologist Jordan Rabinowitz
The atmosphere contains several layers. These layers are differentiated by the composition and temperatures of these layers. One such layer, the stratosphere, warms as height above the Earth’s surface increases. The stratosphere is a layer of the atmosphere that extends some 10 – 15 km above the Earth’s surface. How does it warm? The Earth is protected from harmful ultraviolet rays by a layer of ozone molecules that are located in a region of the atmosphere called the stratosphere. This absorption of UV light is what effectively warms this layer of the atmosphere.
The changes in climate due to changes in ozone start with atmospheric temperatures. As concentrations of ozone increase, the temperatures also must increase. This increase in temperature is because of ozone’s ability to retain heat by processes of absorption. As the sun produces large amounts of ultraviolet light, some of this light passes through the entire atmosphere while some of this ultraviolet light becomes absorbed. Another reason that the stratosphere warms is because this ozone also absorbs infrared radiation that is emitted from the troposphere (the layer below the stratosphere). As concentrations of ozone decrease, so do stratospheric temperatures. Recent studies have concluded that over the past several decades, the stratosphere has cooled nearly 1° to 6° C. Some believe that a link between lower stratospheric temperatures and rising greenhouse gases could exist. A possible positive feedback loop is concerning some scientists. This feedback loop suggests that, as more ozone is lost in the stratosphere, the colder the atmosphere would get due to the loss of ozone. The colder the atmosphere gets the more ozone depletion that will occur.
Ozone and climate interactions are also known at the surface of the Earth. Ozone forms through the interaction of sunlight and photochemistry or how sunlight interacts with certain chemicals. Generally two groups of compounds are known for ozone creation; nitrogen oxides and VOCs or volatile organic compounds. As temperatures increase, chemical processes and interactions tend to increase. As one can expect, because we tend to see an increase in global temperature trends, we can also expect to see more days when ozone would impact human activities. However, there is still some speculation, as some chemical reactions are not modified by warming temperatures. Some scientists also speculate that ozone pollution in the troposphere is caused by a higher probability that higher temperatures will lead to a greater demand for air conditioning. Since most of today’s electricity is generated through power plants, the greater emissions of would likely cause more ozone pollution.
The complex interactions between Earth’s Ozone layer and global warming are a growing concern and an active area of research. While the science has matured greatly over the last several decades, there are many questions that still lack answers, but rest assured there are a number of scientists that are making strides, and finding solutions to complex problems.
To learn more about other interesting weather events, stories, and topics from across the Polar regions, be sure to click on the following link: https://globalweatherclimatecenter.com/polar-regions!
© 2018 Meteorologist Allan Diegan
DISCUSSION: There is no question that as planet Earth continues to gradually warm, both the thickness and the extent of Arctic and aunt Arctic sea ice coverage will evolve as well, which has already been clearly documented by many scientists and scientific organizations alike. In that light, it is important to recognize that as Arctic and/or Antarctic sea ice melts and re-freezes on a season-to-season basis, there are also major fundamental changes which unfold as a direct result of these changes. What is the premier changes that unfolds is the fact that older sea ice tends to melt away and often gets replaced by newer and younger sea ice. This is an important change to the overall character of both the Arctic and Antarctic Circles alike since this indicates that the nature of the polar regions is changing in a rather dramatic way.
More specifically, as older sea ice melts and is later replaced by newer sea ice, this indicates a change in the age of the sea ice being present in either Arctic and/or Antarctic Circle. Hence, this indicates that changes in the age and the overall spatial extent of the net annual sea ice coverage are gradually becoming increasingly more volatile with time. Attached below are a couple of exact excerpts from the original article courtesy of the National Aeronautic and Space Administration which provides even more details on this issue.
“This visualization begins by showing the dynamic beauty of the Arctic sea ice as it responds to winds and ocean currents. Research into the behavior of the Arctic sea ice for the last 30 years has led to a deeper understanding of how this ice survives from year to year. In the animation that follows, age of the sea ice is visible, showing the younger ice in darker shades of blue and the oldest ice in brighter white. This visual representation of the ice age clearly shows how the quantity of older and thicker ice has changed between 1984 and 2016……Furthermore, the issue of the declining sea ice near the North Pole is set in its natural configuration. An analysis of the age of the Arctic sea ice indicates that it traditionally became older while circulating in the Beaufort Sea north of Alaska and was then primarily lost in the warmer regions along the eastern coast of Greenland. In recent years, however, warmer water in the Beaufort Sea, possibly from the Bering Strait, often melts away the sea ice in the summer before it can get older.”
This reality just goes to show that the nature of both Arctic and Antarctic sea ice average thickness and spatial extent is most certainly changing at a more alarming rate and it is that much more important to continue to push and emphasize the value of advocating for more and more productive environmentally-friendly changes to our everyday lives as society continues to evolve with passing time.
To learn more about other interesting weather events, stories, and topics from across the Polar regions, be sure to click on the following link: https://www.globalweatherclimatecenter.com/polar-regions!
© 2018 Meteorologist Jordan Rabinowitz
DISCUSSION: As the Earth continues to undergo a gradual warming trend, one of the hotter topics in science and society is the large variety of issues pertaining to a shrinking percentage of average annual Arctic sea ice coverage. Over the past few decades, there has been a substantial increase in the magnitude of inter-seasonal Arctic sea ice melting. As a result of this increased Arctic sea ice melting, this has created substantial changes in much longer-term Arctic sea ice coverage changes. One of the more notable changes to Arctic sea ice coverage is the fact that the recent increasing rates of sea ice melting are also melting away much older sea ice. This is indicative of the fact that tremendous amounts of Arctic sea ice are being lost both seasonally and annually over the course of recent decades. The defense for this determination is based on the fact that in order for older sea ice to be extinguished, a much greater percentage of the uppermost layers of Arctic sea ice must first melt away.
Therefore, the increasing average temperature across many parts of the greater Arctic Circle are directly causing a major percentage of annual Arctic sea ice to melt away which makes the deeper, older Arctic sea ice much more vulnerable over the course of time. This is a significant change and impact to the overall ice record, since this also induces a more amplified release of carbon dioxide and other trace gases into the atmosphere which furthers the impact of the greenhouse effect. The greenhouse effect is effectively the process by which various gases which exist naturally and/or are anthropogenically-generated are trapped in the middle to upper parts of the atmosphere and consequently trap increasing amounts of heat on Earth. This additional heat being trapped within the global atmosphere surrounding planet Earth acts to further exacerbate the problem of a gradually warming planet. Thus, the average temperature increases in and around the Arctic Circle are a major concern for life on Earth as we continue to get further into the 21st Century.
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© 2018 Meteorologist Jordan Rabinowitz
Natural hazards have always posed a problem. Whether it be an earthquake, volcano or tornado, quick communication has always been able to get the message out and rescue unaware people. With that being stated, the Bogoslof volcano in Alaska may be close to a massive eruption. It has erupted frequently, and it may pose a risk to eagles and aviators alike. Bogoslof, located in the Aleutian Islands, is 850 miles towards the southwest of Anchorage, Alaska. Townspeople will not be affected by ongoing eruptions. On Monday, the volcano erupted, spewing a massive ash cloud protruding into the air, erupting for roughly 3 hours. Ash clouds were seen by pilots in the area and were reported at an estimated 32,000 feet.
Agile work by the National Weather Service is proving to be critical, as many flights are being forced to re-direct their course. Flying directly into a cloud of ash can nearly destroy the aircraft’s engines. It is suggested to fly over or around the ash.
Daily models suggest that ash from Bogoslof will drift southwest and start to spread horizontally outward. Higher ash clouds will be towards the south while lower clouds emerge to the north.
Recently, there has been frequent seismic activity and this volcano could erupt again, causing more headaches for pilots.The National Weather Service, along with others are able to monitor the volcano nonstop.
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©2017 Meteorologist David Tedesco