Average temperature in Finland has risen by more than two degrees

Over the past 166 years, the average temperature in Finland has risen by more than two degrees. During the observation period, the average increase was 0.14 degrees per decade, which is nearly twice as much as the global average.

According to a recent University of Eastern Finland and Finnish Meteorological Institute study, the rise in the temperature has been especially fast over the past 40 years, with the temperature rising by more than 0.2 degrees per decade. "The biggest temperature rise has coincided with November, December and January. Temperatures have also risen faster than the annual average in the spring months, i.e., March, April and May. In the summer months, however, the temperature rise has not been as significant," says Professor Ari Laaksonen of the University of Eastern Finland and the Finnish Meteorological Institute. As a result of the temperature rising, lakes in Finland get their ice cover later than before, and the ice cover also melts away earlier in the spring. Although the temperature rise in the actual growth season has been moderate, observations of Finnish trees beginning to blossom earlier than before have been made.

Temperature has risen in leaps

The annual average temperature has risen in two phases, the first being from the beginning of the observation period to the late 1930s, and the second from the late 1960s to present. Since the 1960s, the temperature has risen faster than ever before, with the rise varying between 0.2 and 0.4 degrees per decade. Between the late 1930s and late 1960s, the temperature remained nearly steady. "The stop in the temperature rise can be explained by several factors, including long-term changes in solar activity and post-World War II growth of human-derived aerosols in the atmosphere. When looking at recent years' observations from Finland, it seems that the temperature rising is not slowing down," University of Eastern Finland researcher Santtu Mikkonen explains.

The temperature time series was created by averaging the data produced by all Finnish weather stations across the country. Furthermore, as the Finnish weather station network wasn't comprehensive nation-wide in the early years, data obtained from measurement stations in Finland's neighbouring countries was also used.

Finland is located between the Atlantic Ocean and the continental Eurasia, which causes great variability in the country's weather. In the time series of the average temperature, this is visible in the form of strong noise, which makes it very challenging to detect statistically significant trends. The temperature time series for Finland was analysed by using a dynamic regression model. The method allows the division of the time series into sections indicating mean changes, i.e. trends, periodic variation, observation inter-dependence and noise. The method makes it possible to take into consideration the seasonal changes typical of Nordic conditions, as well as significant annual variation.

Journal Reference:

S. Mikkonen, M. Laine, H. M. M?kel?, H. Gregow, H. Tuomenvirta, M. Lahtinen, A. Laaksonen. Trends in the average temperature in Finland, 1847–2013. Stochastic Environmental Research and Risk Assessment, 2014; DOI: 10.1007/s00477-014-0992-2

View the original article here

Temperature anomalies are warming faster than Earth's average, study finds

It's widely known that Earth's average temperature has been rising. But research by an Indiana University geographer and colleagues finds that spatial patterns of extreme temperature anomalies -- readings well above or below the mean -- are warming even faster than the overall average.

And trends in extreme heat and cold are important, said Scott M. Robeson, professor of geography in the College of Arts and Sciences at IU Bloomington. They have an outsized impact on water supplies, agricultural productivity and other factors related to human health and well-being.

"Average temperatures don't tell us everything we need to know about climate change," he said. "Arguably, these cold extremes and warm extremes are the most important factors for human society."

Robeson is the lead author of the article "Trends in hemispheric warm and cold anomalies," which will be published in the journal Geophysical Research Letters and is available online. Co-authors are Cort J. Willmott of the University of Delaware and Phil D. Jones of the University of East Anglia.

The researchers analyzed temperature records for the years 1881 to 2013 from HadCRUT4, a widely used data set for land and sea locations compiled by the University of East Anglia and the U.K. Met Office. Using monthly average temperatures at points across the globe, they sorted them into "spatial percentiles," which represent how unusual they are by their geographic size.

Their findings include:

Temperatures at the cold and warm "tails" of the spatial distribution -- the 5th and 95th percentiles -- increased more than the overall average Earth temperature.Over the 130-year record, cold anomalies increased more than warm anomalies, resulting in an overall narrowing of the range of Earth's temperatures.In the past 30 years, however, that pattern reversed, with warm anomalies increasing at a faster rate than cold anomalies. "Earth's temperature was becoming more homogenous with time," Robeson said, "but now it's not."

The study records separate results for the Northern and Southern Hemispheres. Temperatures are considerably more volatile in the Northern Hemisphere, an expected result because there's considerably less land mass in the South to add complexity to weather systems.

The study also examined anomalies during the "pause" in global warming that scientists have observed since 1998. While a 16-year-period is too short a time to draw conclusions about trends, the researchers found that warming continued at most locations on the planet and during much of the year, but that warming was offset by strong cooling during winter months in the Northern Hemisphere.

"There really hasn't been a pause in global warming," Robeson said. "There's been a pause in Northern Hemisphere winter warming."

Co-author Jones of the University of East Anglia said the study provides scientists with better knowledge about what's taking place with Earth's climate. "Improved understanding of the spatial patterns of change over the three periods studied are vital for understanding the causes of recent events," he said.

It may seem counterintuitive that global warming would be accompanied by colder winter weather at some locales. But Robeson said the observation aligns with theories about climate change, which hold that amplified warming in the Arctic region produces changes in the jet stream, which can result in extended periods of cold weather at some locations in the mid-northern latitudes.

And while the rate of planetary warming has slowed in the past 16 years, it hasn't stopped. The World Meteorological Organization announced this month that 2014 is on track to be one of the warmest, if not the warmest, years on record as measured by global average temperatures.

In the U.S., the East has been unusually cold and snowy in recent years, but much of the West has been unusually warm and has experienced drought. And what happens here doesn't necessarily reflect conditions on the rest of the planet. Robeson points out that the United States, including Alaska, makes up only 2 percent of Earth's surface.

View the original article here

Corals don’t lie: Centuries of rising ocean levels and temperature data revealed

AIMS researchers plus a team in the College of Wa, CSIRO and also the College of North Park have analysed barrier cores in the eastern Indian Sea to know the way the unique barrier reefs of Wa are influenced by altering sea power and water temps. The study was released today within the worldwide journal Character Communications. The findings give new experience into how La Ni?a, an environment swing within the tropical Off-shore, affects the Leeuwin current and just how our oceans are altering.

“Due to the possible lack of lengthy-term findings of marine climate we used lengthy barrier cores, with annual growth bands much like tree rings, to supply a record of history. We acquired records of past ocean temps by calculating caffeine composition from the barrier skeleton from year upon year. This demonstrated how altering winds and sea power within the eastern Indian Sea are impelled by climate variability within the western tropical Gulf Of Mexico,” stated Dr Jens Zinke (Assistant Professor in the UWA Oceans Institute and AIMS-UWA researcher). The lengthy barrier records permitted the researchers to check out these designs of climate variability to 1795 AD.

La Ni?a occasions within the tropical Off-shore create a increased Leeuwin Current and abnormally tepid to warm water temps and greater ocean levels off southwest Wa.

“A prominent example may be the 2011 warmth wave along WA’s reefs which brought to barrier bleaching and seafood kills,” stated Dr Ming Feng CSIRO Principal Research Researcher.?

The worldwide team discovered that additionally to warming ocean surface temps, ocean-level variability and Leeuwin Current strength have elevated since 1980. The barrier cores also demonstrate that the strong winds and extreme weather of 2011 off Wa are highly improbable poor yesteryear 215 years. The authors conclude this is obvious evidence that climatic change and ocean-level rise is growing the seriousness of these extreme occasions which change up the highly diverse barrier reefs of Wa, such as the Ningaloo Reef World Heritage site.

“Given ongoing global global warming, Chances are that future La Ni?a occasions can lead to more extreme warming and ocean-level occasions with potentially significant effects for that upkeep of Western Australia's unique marine environments,” stated Dr Janice Lough, AIMS Senior Principal Research Researcher.

The scientists used core examples of massive Porites colonies in the Houtman-Abrolhos Islands, probably the most southerly reefs within the Indian Sea that are directly within the road to the Leeuwin Current. While using chemical composition from the annual barrier growth bands they could rebuild ocean surface temperature and Leeuwin Current for 215 years, from 1795 to 2010.

Journal Reference:

J. Zinke, A. Rountrey, M. Feng, S.-P. Xie, D. Dissard, K. Rankenburg, J.M. Lough, M.T. McCulloch. Corals record lengthy-term Leeuwin current variability including Ningaloo Ni?o/Ni?a since 1795. Character Communications, 2014 5 DOI: 10.1038/ncomms4607

View the original article here

Pacific Ocean temperature influences tornado activity in US

Meteorologists often use information about warm and cold fronts to determine whether a tornado will occur in a particular area. Now, a University of Missouri researcher has found that the temperature of the Pacific Ocean could help scientists predict the type and location of tornado activity in the U.S.

Laurel McCoy, an atmospheric science graduate student at the MU School of Natural Resources, and Tony Lupo, professor and chair of atmospheric science in the College of Agriculture, Food and Natural Resources, surveyed 56,457 tornado-like events from 1950 to 2011. They found that when surface sea temperatures were warmer than average, the U.S. experienced 20.3 percent more tornados that were rated EF-2 to EF-5 on the Enhanced Fuijta (EF) scale. (The EF scale rates the strength of tornados based on the damage they cause. The scale has six category rankings from zero to five.)

McCoy and Lupo found that the tornados that occurred when surface sea temperatures were above average were usually located to the west and north of tornado alley, an area in the Midwestern part of the U.S. that experiences more tornados than any other area. McCoy also found that when sea surface temperatures were cooler, more tornadoes tracked from southern states, like Alabama, into Tennessee, Illinois and Indiana.

"Differences in sea temperatures influence the route of the jet stream as it passes over the Pacific and, eventually, to the United States," McCoy said. "Tornado-producing storms usually are triggered by, and will follow, the jet stream. This helps explain why we found a rise in the number of tornados and a change in their location when sea temperatures fluctuated."

In the study, McCoy and Lupo examined the relationship between tornadoes and a climate phenomenon called the Pacific Decadal Oscillation (PDO). PDO phases, which were discovered in the mid-1990s, are long-term temperature trends that can last up to 30 years. According to NASA scientists, the current PDO phase has just entered into a "cool" state.

"PDO cool phases are characterized by a cool wedge of lower than normal sea-surface ocean temperatures in the eastern Pacific and a warm horseshoe pattern of higher than normal sea-surface temperatures extending into the north, west and southern Pacific," McCoy said. "In the warm phase, which lasted from 1977 to 1999, the west Pacific Ocean became cool and the wedge in the east was warm."

In 2011, more than 550 deaths occurred as a result of tornadoes, resulting in more than $28 billion in property damage, according to the U.S. National Oceanic and Atmospheric Administration. McCoy says that with her findings, officials may be able to save lives in the future.

"Now that we know the effects of PDO cool and warm phases, weather forecasters have another tool to predict dangerous storms and inform the public of impending weather conditions," McCoy said.

The research will be presented at the National Weather Association Conference this fall.

Cite This Page:

University of Missouri-Columbia. "Pacific Ocean temperature influences tornado activity in US." ScienceDaily. ScienceDaily, 17 October 2013. .University of Missouri-Columbia. (2013, October 17). Pacific Ocean temperature influences tornado activity in US. ScienceDaily. Retrieved February 1, 2014 from www.sciencedaily.com/releases/2013/10/131017174043.htmUniversity of Missouri-Columbia. "Pacific Ocean temperature influences tornado activity in US." ScienceDaily. www.sciencedaily.com/releases/2013/10/131017174043.htm (accessed February 1, 2014).

View the original article here