Posts Tagged ‘Northern Hemisphere’

Little Ice Age could well have resulted from reduced solar activity

October 4, 2013

This paper is particularly interesting because the senior author, Thomas Stocker, is the Vice-Chair of the IPCC and presented the summary of AR5 at the Press Conference last week!!

It is very strange then that the IPCC is so nonchalant about solar effects. In any event whatever the various climate models say, the Landscheidt Minimum is here and global cooling will continue for the next two decades or so. As The Register puts it.
” There’s been criticism for the Intergovernmental Panel on Climate Change (IPCC) over its latest AR5 report from many quarters for many reasons. But today there’s new research focusing on one particular aspect of that criticism.The particular part of the IPCC’s science in question is its accounting for the effects of changes in the Sun on the climate of planet Earth. Many climatologists have long sought to suggest that the effects of solar variability are minor, certainly when compared to those of human-driven CO2 emissions. Others, however, while admitting that the Sun changes only a very little over human timescales, think that it might be an important factor. This matters because solar physicists think that the Sun is about to enter a “grand minimum”, a prolonged period of low activity. 
The current 11-year peak in solar action is the weakest seen for a long time, and it may presage a lengthy quiet period. Previously, historical records suggest that such periods have been accompanied by chilly conditions on Earth – perhaps to the point where a coming minimum might counteract or even render irrelevant humanity’s carbon emissions. The “Little Ice Age” seen from the 15th to the 19th centuries is often mentioned in this context.
Lehner, Flavio, Andreas Born, Christoph C. Raible, Thomas F. Stocker, 2013: Amplified Inception of European Little Ice Age by Sea Ice–Ocean–Atmosphere Feedbacks.  J. Climate26, 7586–7602.
doi: http://dx.doi.org/10.1175/JCLI-D-12-00690.1
The University of Berne press release writes:
The study that was realized at the OCCR shows that volcanic eruptions and reduced solar radiation caused global cooling between the thirteenth and the fifteenth centuries. The resulting accelerated formation of sea ice in the Northern Seas triggered a positive feedback process that shaped the Little Ice Age. The winter weather in Europe is largely governed by the so-called North Atlantic Oscillation (NAO). ……. Until now, the NAO was believed to be jointly responsible for the cooling in the early fifteenth century along with volcanic eruptions and weakened solar radiation. The subsequent Little Ice Age continued into the nineteenth century. Now, however, Bernese climate researchers Flavio Lehner, Andreas Born, Christoph Raible and Thomas Stocker reveal that the Little Ice Age was also able to take its course without the influence of the NAO, driven purely by the consequences of strong and frequent volcanic eruptions at the time, a reduced solar radiation, or both together.
Using simulations on the CSCS supercomputer “Monte Rosa”, the climate researchers searched for a feedback process that was capable of triggering the Little Ice Age.
….. For the scientists, the fact that all the slightly altered, realistic simulations and the synthetic ice simulation yielded consistent results is solid proof that the Little Ice Age was primarily governed by external triggers. Volcanic activity and less solar radiation initially caused an increase in sea-ice formation independently of atmospheric circulation. Due to the cooling, the mean sea level pressure gradually increased over the Barents Sea, which enabled the cold air to reach Europe. “However, this pressure response is clearly a delayed reaction of the atmosphere to the preceding processes in the ocean,” says Raible.
Abstract: The inception of the Little Ice Age (~1400–1700 AD) is believed to have been driven by an interplay of external forcing and climate system internal variability. While the hemispheric signal seems to have been dominated by solar irradiance and volcanic eruptions, the understanding of mechanisms shaping the climate on a continental scale is less robust. In an ensemble of transient model simulations and a new type of sensitivity experiments with artificial sea ice growth, the authors identify a sea ice–ocean–atmosphere feedback mechanism that amplifies the Little Ice Age cooling in the North Atlantic–European region and produces the temperature pattern suggested by paleoclimatic reconstructions. Initiated by increasing negative forcing, the Arctic sea ice substantially expands at the beginning of the Little Ice Age. The excess of sea ice is exported to the subpolar North Atlantic, where it melts, thereby weakening convection of the ocean. Consequently, northward ocean heat transport is reduced, reinforcing the expansion of the sea ice and the cooling of the Northern Hemisphere. In the Nordic Seas, sea surface height anomalies cause the oceanic recirculation to strengthen at the expense of the warm Barents Sea inflow, thereby further reinforcing sea ice growth. The absent ocean–atmosphere heat flux in the Barents Sea results in an amplified cooling over Northern Europe. The positive nature of this feedback mechanism enables sea ice to remain in an expanded state for decades up to a century, favoring sustained cold periods over Europe such as the Little Ice Age. Support for the feedback mechanism comes from recent proxy reconstructions around the Nordic Seas
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Arctic summer relatively short and ice melt-rate slow this year

August 9, 2013

The Arctic ice extent usually reaches a maximum in the 2nd week of March and its minimum during the 2nd week of September.

This year the Arctic summer started later than usual (long winter, late spring all over the Northern hemisphere). Now as Arctic temperatures have already dropped below freezing it could turn out to be a rather short. cool summer. Temperatures rose to above freezing about 3 weeks later than the average and seem to have dropped below zero about 2 weeks ahead of the average. In consequence the ice melt-rates have been much lower than for some time (but not unprecedented by a long way).

Arctic Temperatures North of 80° ( from DMI – Danish Centre for Ocean and Ice)

Daily mean temperatures for the Arctic area north of the 80th northern parallel, plotted with daily climate values calculated from the period 1958-2002.

Calculation of the Arctic Mean Temperature

The daily mean temperature of the Arctic area north of the 80th northern parallel is estimated from the average of the 00z and 12z analysis for all model grid points inside that area. The ERA40 reanalysis data set from ECMWF, has been applied to calculate daily mean temperatures for the period from 1958 to 2002, from 2002 to 2006 data from the global NWP model T511 is used and from 2006 to 2010 T799 data are used and from 2010 to present the T1279 model data are used. 

The ERA40 reanalysis data, has been applied to calculation of daily climate values that are plotted along with the daily analysis values in all plots. The data used to determine climate values is the full ERA40 data set, from 1958 to 2002.
More information can be found here.

Daily mean temperature and climate north of the 80th northern parallel, as a function of the day of year. DMI

Daily mean temperature and climate north of the 80th northern parallel, as a function of the day of year. DMI

Not surprisingly the ice melt-rate this year has been relatively low and the ice extent relatively high.

Total sea ice extent on the northern hemisphere during the past years, including climate mean; plus/minus 1 standard deviation. The ice extent values are calculated from the ice type data from theOcean and Sea Ice, Satellite Application Facility (OSISAF), where areas with ice concentration higher than 15% are classified as ice.

The total area of sea ice is the sum of First Year Ice (FYI), Multi Year Ice (MYI) and the area of ambiguous ice types, from the OSISAF ice type product.

Sea ice extent in recent years for the northern hemisphere.                        The grey shaded area corresponds to the climate mean                       plus/minus 1 standard deviation.

Sea ice extent in recent years for the northern hemisphere.
The grey shaded area corresponds to the climate mean plus/minus 1 standard deviation.

It looks probable that the ice extent minimum for 2013 will be within one standard deviation of the mean 1979-2000 value.

The sun at solstice 12.12 CET on 21.12.2012

December 22, 2012

The shortest day of the year has come and gone and the countdown to summer (in the Northern Hemisphere) has begun. From a day length of 6 hours 15 minutes yesterday the next 183 days will see the length of the day – at this latitude – increasing by an average of over 3 minutes every day reaching a day length of almost 17 hours at the summer solstice.

From Discovery News:

At 11:12 UT (6:12 a.m. EST), the world didn’t end (as far as I can tell), but it was a significant time none-the-less. That was the exact minute of the Winter Solstice in the Northern Hemisphere (or the Summer Solstice in the Southern Hemisphere) — when the daylight hours are shortest and the sun reaches its most southern position in the sky at noon.

Sun-solstice

The sun at solstice 12:12 CET on 21.12.2012: image NASA

NASA Solar Dynamics Observatory (SDO) captured the time of solstice from orbit. Although the SDO is always imaging the sun through a multitude of filters, this is a great excuse to showcase the fantastic beauty of our nearest star, while putting all the doomsday nonsense behind us.

The sun didn’t unleash a killer solar flare or devastating coronal mass ejection, but it is undergoing a fascinating period in its solar cycle.

As can be seen from the SDO image above, the solar magnetic field is twisted and warped, channeling million-degree plasma high into the sun’s atmosphere in the form of beautiful coronal loops. This is all because the sun is fast approaching “solar maximum” — an exciting time when the sun’s magnetic field is most stressed.

Self-correcting feedback mechanisms? When warming leads to cooling

February 28, 2012

An interesting paper from Curry et al. providing further evidence of a relationship between melting ice in the Arctic regions and widespread cold outbreaks in the Northern Hemisphere. Forcing mechanisms are all the rage where feedback loops lead to runaway effects. In general – in my experience with things technical – natural feedback loops are most often self-correcting. Sometimes they may appear in the short-term to amplify effects but in the long-term they drive back to an equilibrium condition. If feedback mechanisms are not known or if the true cycle-time of the feedback is unknown then short-term effects can be misleading.

Jiping Liu, Judith A. Curry, Huijun Wang, Mirong Song, and Radley M. Horton. Impact of declining Arctic sea ice on winter snowfallProceedings of the National Academy of Sciences, February 27, 2012 DOI:10.1073/pnas.1114910109

Newswise: 

Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, northwestern and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.

“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech. “The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”

New papers confirm solar effects could bring on little ice ages

October 10, 2011

There seems to be a renewal of interest in solar effects on climate change and especially on little ice ages. It would be too much to expect an early abandonment of the carbon dioxide hypothesis. Equally unlikely is any acknowledgement that carbon dioxide in the atmosphere is of insignificant influence for climate. But the acknowledgement of solar influences on climate helps to redress some of the balance.

The UK Met office research referred to in yesterday’s Sunday Times article might well refer to this paper in Nature Geoscience published online yesterday which makes the link between UV radiation variation during solar cycles and cold winters in the Northern hemisphere. The authors are from the Met Office Hadley Centre, Oxford and Imperial College.

Solar forcing of winter climate variability in the Northern Hemisphere by Sarah Ineson, Adam A. Scaife, Jeff R. Knight, James C. Manners, Nick J. Dunstone, Lesley J. Gray & Joanna D. Haigh  Nature Geoscience (2011) doi:10.1038/ngeo1282

Sarah Ineson – Met Office Hadley Centre, FitzRoy Road, Exeter, Devon EX1 3PB, UK 

Abstract:An influence of solar irradiance variations on Earth’s surface climate has been repeatedly suggested, based on correlations between solar variability and meteorological variables. Specifically, weaker westerly winds have been observed in winters with a less active sun, for example at the minimum phase of the 11-year sunspot cycle. With some possible exceptions, it has proved difficult for climate models to consistently reproduce this signal. Spectral Irradiance Monitor satellite measurements indicate that variations in solar ultraviolet irradiance may be larger than previously thought. Here we drive an ocean–atmosphere climate model with ultraviolet irradiance variations based on these observations. We find that the model responds to the solar minimum with patterns in surface pressure and temperature that resemble the negative phase of the North Atlantic or Arctic Oscillation, of similar magnitude to observations. In our model, the anomalies descend through the depth of the extratropical winter atmosphere. If the updated measurements of solar ultraviolet irradiance are correct, low solar activity, as observed during recent years, drives cold winters in northern Europe and the United States, and mild winters over southern Europe and Canada, with little direct change in globally averaged temperature. Given the quasiregularity of the 11-year solar cycle, our findings may help improve decadal climate predictions for highly populated extratropical regions.

A sceond paper in Nature Geoscience also released online yesterday reports that simulations with a climate model using new observations of solar variability suggest a substantial influence of the Sun on the winter climate in the Northern Hemisphere.

Atmospheric science: Solar cycle and climate predictions by Katja Matthes Nature Geoscience (2011) doi:10.1038/ngeo1298

Katja Matthes is at the Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany

Interestingly a paper from 2001 with Michael Mann and Gavin Schmidt  (of climategate infamy) as co-authors has similar findings:

Solar Forcing of Regional Climate Change During the Maunder Minimum by Drew T. Shindell, Gavin A. Schmidt, Michael E. Mann, David Rind and Anne Waple,  Science 7 December 2001: Vol. 294 no. 5549 pp. 2149-2152 DOI: 10.1126/science.1064363

Abstract:We examine the climate response to solar irradiance changes between the late 17th-century Maunder Minimum and the late 18th century. Global average temperature changes are small (about 0.3° to 0.4°C) in both a climate model and empirical reconstructions. However, regional temperature changes are quite large. In the model, these occur primarily through a forced shift toward the low index state of the Arctic Oscillation/North Atlantic Oscillation as solar irradiance decreases. This leads to colder temperatures over the Northern Hemisphere continents, especially in winter (1° to 2°C), in agreement with historical records and proxy data for surface temperatures.

Update! The BBC reports on this story here but takes great care to pay due respect to global warming orthodoxy with the statement “The researchers emphasise there is no impact on global warming”.

Of course not – It’s only the sun stupid! And what can the sun possibly have to do with warming the planet?!

Related:

Colder winters to come and solar influence on climate beginning to get its due

Is the Landscheidt minimum a precursor for a grand minimum? 

Another harsh winter is expected as La Niña returns

September 9, 2011

Yesterday the NOAA finally confirmed that  La Niña was back. 

The Indian monsoon has been reasonably good and we can expect  greater evaporation leading to increased rains in the Western Pacific and in Australia. There should be less rain in the Eastern Pacific on the western coast of S. America (coastal Chile and Peru) but increased rain on the east coast in southern Brazil and  northern Argentina. Dry conditions should persist in the Southern US but the Northern hemisphere can now expect another harsh winter for the third year in a row. Forecasters are beginning to warn about this and local authorities are preparing to stock adequate amounts of salt and grit.

Sweden: Forecasters promise another harsh winter 

While Swedes are still enjoying the relatively clement weather of early autumn, weather experts are already forecasting another freezing winter to follow the last two. ”It is true that they generally follow each other,” said meteorologist Lisa Frost from the Swedish Meteorological and Hydrological Institute (SMHI) to daily Aftonbladet.
According to experts, the last two winters have been the coldest for the last few decades and statistics from the institute all point to cold winters coming in threes. …. The three extremely cold winters 1940-43, during the war, were followed by four very clement winters. Since then, the weather would seem to have followed this 3.5 year pattern.

Scotland: New bid to avoid repeat of winter road chaos 

The Scottish Government has called in the Red Cross to help prepare for the possibility of another harsh winter. In a bid to avoid a repeat of last year when motorists were stranded for hours on snow- bound motorways, transport minister Keith Brown has called a ‘Get Ready For Winter’ week next month.

Ireland: Heavy snow promised in Ireland  

The Irish Government has told Irish households to stock up on disposable barbecues to avoid disasters during the freezing weather promised for the forthcoming winter. After studying the last two years bitterly cold winters and the situations which arose the Government has advised that citizens should have “some barbecue trays” to hand in case they get snowed in.

UK: Forecaster Predicts Early Winter Snowfall For Ireland And Britain 

A long range weather forecaster is predicting an early start to winter 2011-2012 for many regions of the United Kingdom and Ireland.  James Madden of Exacta Weather says heavy snowfalls are likely in places as soon as late October and early November.

US: Resurgent La Niña may enhance snowfall for northern Colo. ski areas this winter 

… the Climate Prediction Center (CPC) at the National Oceanic and Atmospheric Administration (NOAA ) has issued a La Niña Advisory. This means La Niña conditions are likely to drive weather trends this winter. … “At this time, the Climate Forecast System (CFS) models are predicting an episode rivaling the same strength as last winter, but that forecast may change quite a bit as we get closer to the winter.”

Last winter, a moderate La Niña in the Pacific Ocean helped generate conditions just right for continuous massive snowfall in the Rocky Mountains of central and northern Colorado.

Related: Newborn La Niña: An Illustrated Guide

La Niña will last well into 2011 and could extend into 2012

February 5, 2011

A new article has been posted on the National Oceanic & Atmospheric Administration website and comes to the conclusion that there is an even chance that La Niña conditions could extend into 2012:

Multivariate ENSO Index (MEI) by Klaus Wolter 4th February 2011

El Niño/Southern Oscillation (ENSO) is the most important coupled ocean-atmosphere phenomenon to cause global climate variability on interannual time scales. Here we attempt to monitor ENSO by basing the Multivariate ENSO Index (MEI) on the six main observed variables over the tropical Pacific. These six variables are: sea-level pressure (P), zonal (U) and meridional (V) components of the surface wind, sea surface temperature (S), surface air temperature (A), and total cloudiness fraction of the sky (C). …… Negative values of the MEI represent the cold ENSO phase, a.k.a.La Niña, while positive MEI values represent the warm ENSO phase (El Niño)………

Discussion and comparison of recent conditions with historic La Niña events

In the context of the rapid transition of the MEI into strong La Niña conditions, this section features a comparison figure with strong La Niña events that all reached at least minus one standard deviations by June-July, and a peak of at least -1.4 sigma over the course of an event. The most recent moderate La Niña events of 1998-2001 and 2007-09 did not qualify, since they either did not reach the required peak anomaly (the first one) or became strong too late in the calendar year (both).

The updated (December-January) MEI value has strengthened slightly to -1.62 standard deviations after almost dropping below -2 standard deviations in August-September. Nevertheless, the most recent value ranks 2nd for this time of year, clearly below the 10%-tile threshold for strong La Niña MEI rankings , but slightly weaker than the value recorded in 1974. If one were to take the average of all MEI rankings since July-August (a six-month period), the strongest La Niña half-year periods of mid-55, ’73-74, and late ’75 averaged slightly stronger than the current event, for now (this is means Rank 4 for the current event, up one from last month).
Negative SST anomalies are covering much of the eastern (sub-)tropical Pacific in the latest weekly SST map. Many of these anomalies are in excess of -1C.
For an alternate interpretation of the current situation, I highly recommend reading the latest NOAA ENSO Advisory which represents the official and most recent Climate Prediction Center opinion on this subject. In its latest update (6 January 2011), La Niña conditions are expected to last “well” into the Northern Hemisphere spring of 2011. …….. While La Niña conditions are guaranteed well into 2011, it remains to be seen whether it can rally once more to cross the -2 sigma barrier, and/or whether it will indeed last into 2012, as discussed six months ago on this page. I believe the odds for a two-year event remain well above 50%, made even more likely by the continued unabated strength in various ENSO indices.

It seems self-evident ( even if not fashionable or politically correct) that the sun controls our climate and that the oceans do the sun’s bidding as they drive the atmosphere which then determines our weather.

The consequences of an extended La Niña into 2011 / 2012 could be

  • another good monsoon year in India,
  • a cold winter again for 2011/2012 in the Northern hemishere



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