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jethro

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Posted
  • Location: Camborne
  • Location: Camborne

Decelerating Atlantic meridional overturning circulation main cause of future west European summer atmospheric circulation changes

 

We use state-of-the-art global climate models and observations to show that the projected higher pressures over the British Isles due to global warming are part of an atmospheric response to the decelerating Atlantic meridional overturning circulation (AMOC) causing a reduction in the associated northward heat transport, keeping the North Atlantic relatively cool. However, considerable inter-model differences in the projected weakening of the AMOC lead to a large spread in the projected wind changes. Hence, the uncertainty in the projected reduction of oceanic heat transport is a main source of uncertainty in projections of Western European climate change. Better-constrained projections of European summer climate thus rely heavily on a more realistic representation of ocean processes in climate models.

 

Open Access

 

http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094007/meta

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Posted
  • Location: Western Isle of Wight
  • Weather Preferences: Snow, Storm, anything loud and dramatic.
  • Location: Western Isle of Wight

I just read  http://www.smh.com.au/technology/sci-tech/prehistoric-frankenvirus-mollivirus-sibericum-uncovered-in-siberian-permafrost-20150909-gjial2.html

 

They have awoken ancient viruses :--  "we cannot rule out that distant viruses of ancient Siberian human populations could re-emerge as Arctic permafrost layers melt and/or are disrupted by industrial activities".

 

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Not sure where to put this but a non technical article by Kate Marvel, climatologist and ex-cosmologist.

 

The Hidden Importance of Clouds

http://nautil.us/issue/25/water/the-hidden-importance-of-clouds

What a wonderful piece that is, knocks; it's clear and concise and appreciative of all the inherent uncertainties.

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Posted
  • Location: Camborne
  • Location: Camborne

What a wonderful piece that is, knocks; it's clear and concise and appreciative of all the inherent uncertainties.

 

As per normal for her Pete. She also has a great sense of humour

 

http://marvelclimate.blogspot.co.uk/

 

Her study

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00734.1

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

An interesting read here, 

 

http://clivebest.com/blog/?p=6778

 

 

Observation of a tidal effect on the Polar Jet Stream


C. H. Best1 and R. Madrigali2
1Independent Scientist, Huntingdon, UK
2Independent Scientist, Grosseto, Italy


Received: 20 Apr 2015 – Accepted: 31 Jul 2015 – Published: 25 Aug 2015
Abstract. Variations in the Polar Jet Stream directly affect weather across Europe and North America (Francis et al., 2012). Jet Stream dynamics are governed by the development of planetary Rossby waves (Dickinson, 1978) driven by variation of the Coriolis force with latitude. Here we show that increasing atmospheric tides induce the development of Rossby waves, especially during winter months. This changes the flow and direction of the Jet Stream, as measured by the Arctic Oscillation (AO). Although horizontal tidal forces are tiny (107 smaller than gravity), they act over huge areas dragging the Jet Stream flow southwards in regular pulses as the earth rotates. This induces a changing Coriolis torque, which then distorts the Jet Stream flow. The data from eight recent winters are studied indicating that the AO is anti-correlated to the horizontal "tractional" component of tides acting between latitude 45 and 60° N. The observed 28 day cycle in Jet Stream flow and extent has a statistical significance > 99 %. A cross-correlation between all daily AO data since 1950 and the tractional tidal strength shows a significant anti-correlation with a lag time of ~ 5 days. The strongest correlation and largest excursions of the AO are observed during winter 2005/2006 – a maximum lunar standstill year. This declination dependence of tidal forces at high latitudes is the proposed cause of many previous reports of an 18.6 year dependence of continental rainfall and drought. http://www.atmos-chem-phys-discuss.net/15/22701/2015/acpd-15-22701-2015.html
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Posted
  • Location: Camborne
  • Location: Camborne

The Industrial Revolution put an end to 1,800 years of ocean cooling

 

The high frequency and magnitude of volcanic eruptions could have been the cause of the progressive cooling of ocean surfaces over a period of 1,800 years. This is made apparent in an international study published recently in the journal Nature Geoscience, involving researcher P. Graham Mortyn of the Institute for Environmental Science and Technology (ICTA-UAB) and the UAB Department of Geography.

The study emphasises that this trend came to an end with the beginning of the Industrial Revolution and the resulting global warming caused by human activity. It further shows that the lowest temperatures in the first 1,800 years of the Common Era were recorded between the 16th and the 18th centuries, a period known as the "Little Ice Age".

 

http://www.uab.cat/web/newsroom/news-detail/the-industrial-revolution-put-an-end-to-1-800-years-of-ocean-cooling-1345668003610.html?noticiaid=1345690621284

 

Paper

 

http://www.nature.com/ngeo/journal/v8/n9/abs/ngeo2510.html

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The reinvigoration of the Southern Ocean carbon sink

 

Several studies have suggested that the carbon sink in the Southern Ocean—the ocean’s strongest region for the uptake of anthropogenic CO2 —has weakened in recent decades. We demonstrated, on the basis of multidecadal analyses of surface ocean CO2 observations, that this weakening trend stopped around 2002, and by 2012, the Southern Ocean had regained its expected strength based on the growth of atmospheric CO2. All three Southern Ocean sectors have contributed to this reinvigoration of the carbon sink, yet differences in the processes between sectors exist, related to a tendency toward a zonally more asymmetric atmospheric circulation. The large decadal variations in the Southern Ocean carbon sink suggest a rather dynamic ocean carbon cycle that varies more in time than previously recognized.

 

http://www.sciencemag.org/content/349/6253/1221

 

Article

 

http://www.carbonbrief.org/blog/2015/09/southern-ocean-carbon-sink-bounces-back-with-renewed-vigour/?utm_source=Daily+Carbon+Briefing&utm_campaign=2f79b06285-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-2f79b06285-303447709

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Posted
  • Location: Camborne
  • Location: Camborne

Out of interest the data up to the beginning of this month.

 

With the satellite altimetry missions, the global mean sea level (GMSL) has been calculated on a continual basis since January 1993. 'Verification' phases, during which the satellites follow each other in close succession (Topex/Poseidon--Jason-1, then Jason-1--Jason-2), help to link up these different missions by precisely determining any bias between them. Saral, Envisat, ERS-1 and ERS-2 are also used, after being adjusted on these reference missions, in order to compute Mean Sea Level at high latitudes (higher than 66°N and S), and also to improve spatial resolution by combining all these missions together. In addition, permanent monitoring of quality during the missions (Calval) and studies of the necessary corrections of altimetry data regularly add to our understanding and knowledge (see the Processing and corrections applied to each mission to obtain the reference mean sea level).

 

http://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/actualitesindicateurs-des-oceansniveau-moyen-des-mersindexhtml.html

post-12275-0-98816800-1441980773_thumb.p

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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.

Some new research on the efforts to identify waves that will develop into tropical cyclones.

 

http://onlinelibrary.wiley.com/doi/10.1002/qj.2616/abstract

 

 

Tracking pre-genesis tropical cyclones is important for earlier detection of developing systems as well as targeting potential locations for dropsondes in field experiments. The use of a reference frame moving with the disturbance gives a more accurate depiction of streamlines and closed circulation than the Earth-relative frame. However, identification of recirculating regions does not require a choice of reference frame when marked by the Galilean invariant Eulerian Okubo–Weiss (OW) parameter. While the Eulerian OW parameter is generally effective at identifying vortex cores at a given place and a given time, it has its limitations in weak disturbances and in time-dependent flows. Integrating the eigenvalue of the velocity gradient tensor along particle trajectories provides a time-smoothing of the Eulerian OW parameter, and provides earlier detection with fewer false alarms. We refer to this integration along trajectories as the Lagrangian OW parameter. When mapped to a horizontal grid it becomes a Lagrangian OW field.

The Lagrangian OW field has advantages over the Eulerian OW field in the detail of additional flow structures that it identifies. The Lagrangian OW field shows the Lagrangian boundaries that are present as a disturbance develops from an easterly wave, and a shear sheath that forms when a disturbance becomes self-sustaining, typically at tropical storm strength. Since all of these structures are Lagrangian, they are advected with the flow field, and display the continuous evolution of coherent flow features as the fluid evolves.

Examples of the use of the Lagrangian OW field are given for ECMWF forecast data from the 2014 Atlantic hurricane season. All of the Lagrangian coherent structures that can be identified by this field are shown for developing disturbances and mature cyclones. The Lagrangian OW field also shows additional details of vortex mergers, and is used to identify a stable crystal lattice configuration in which vorticity does not aggregate.

 

A loop of the process in action.

 

http://www.met.nps.edu/~mtmontgo/Lag_html/2015/OWB.loop.latest.atlantic.ecmwf.html

 

Website as the link back doesn't work.

 

http://www.met.nps.edu/~mtmontgo/storms2015-atlantic.html

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Posted
  • Location: Camborne
  • Location: Camborne

Sierra Nevada snowpack lowest in five centuries

 

California is currently experiencing a record-setting drought that started in 2012 and recently culminated in the first ever mandatory state-wide water restriction1. The snowpack conditions in the Sierra Nevada mountains present an ominous sign of the severity of this drought: the 1 April 2015 snow water equivalent…

 

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2809.html

 

Article

 

Sierra Nevada snowpack lowest in five centuries

http://www.sciencedaily.com/releases/2015/09/150914114528.htm

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Posted
  • Location: Ireland, probably South Tipperary
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Ireland, probably South Tipperary

Solar forcing synchronizes decadal North Atlantic climate variability

 

Quasi-decadal variability in solar irradiance has been suggested to exert a substantial effect on Earth’s regional climate. In the North Atlantic sector, the 11-year solar signal has been proposed to project onto a pattern resembling the North Atlantic Oscillation (NAO), with a lag of a few years due to ocean-atmosphere interactions. The solar/NAO relationship is, however, highly misrepresented in climate model simulations with realistic observed forcings. In addition, its detection is particularly complicated since NAO quasi-decadal fluctuations can be intrinsically generated by the coupled ocean-atmosphere system. Here we compare two multi-decadal ocean-atmosphere chemistry-climate simulations with and without solar forcing variability. While the experiment including solar variability simulates a 1–2-year lagged solar/NAO relationship, comparison of both experiments suggests that the 11-year solar cycle synchronizes quasi-decadal NAO variability intrinsic to the model. The synchronization is consistent with the downward propagation of the solar signal from the stratosphere to the surface.

 

 

Science daily piece on it is here

 

New perspectives for long-term climate predictions

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Posted
  • Location: Camborne
  • Location: Camborne

Limits to the quantification of local climate change

 

We demonstrate how the fundamental timescales of anthropogenic climate change limit the identification of societally relevant aspects of changes in precipitation. We show that it is nevertheless possible to extract, solely from observations, some confident quantified assessments of change at certain thresholds and locations. Maps of such changes, for a variety of hydrologically-relevant, threshold-dependent metrics, are presented. In places in Scotland, for instance, the total precipitation on heavy rainfall days in winter has increased by more than 50%, but only in some locations has this been accompanied by a substantial increase in total seasonal precipitation; an important distinction for water and land management. These results are important for the presentation of scientific data by climate services, as a benchmark requirement for models which are used to provide projections on local scales, and for process-based climate and impacts research to understand local modulation of synoptic and global scale climate. They are a critical foundation for adaptation planning and for the scientific provision of locally relevant information about future climate.

 

Open access

 

http://iopscience.iop.org/article/10.1088/1748-9326/10/9/094018/meta;jsessionid=707A2484C9BF5C496DF2CB59496C782E.c1

 

Article

 

http://www.eurekalert.org/pub_releases/2015-09/uow-ts091515.php

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Posted
  • Location: Camborne
  • Location: Camborne

Global warming 'hiatus' never happened, Stanford scientists say

 

A new study reveals that the evidence for a recent pause in the rate of global warming lacks a sound statistical basis. The finding highlights the importance of using appropriate statistical techniques and should improve confidence in climate model projections.

 

http://news.stanford.edu/news/2015/september/global-warming-hiatus-091715.html

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Posted
  • Location: Camborne
  • Location: Camborne

Solving the problem of Arctic sea ice thickness distribution using molecular concepts

Yale University scientists have answered a 40-year-old question about Arctic ice thickness by treating the ice floes of the frozen seas like colliding molecules in a fluid or gas.

 

http://www.sciencedaily.com/releases/2015/09/150917135217.htm?utm_source=twitterfeed&utm_medium=twitter&utm_campaign=Feed%3A+Cryonews+%28CryoNews%29

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Posted
  • Location: Camborne
  • Location: Camborne

Global warming 'hiatus' never happened, Stanford scientists say

 

A new study reveals that the evidence for a recent pause in the rate of global warming lacks a sound statistical basis. The finding highlights the importance of using appropriate statistical techniques and should improve confidence in climate model projections.

 

http://news.stanford.edu/news/2015/september/global-warming-hiatus-091715.html

 

I think it worth posting this, A short critique of this paper by Tamino.

 

https://tamino.wordpress.com/2015/09/18/right-and-wrong/

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Posted
  • Location: Camborne
  • Location: Camborne

El Niño and La Niña will Exacerbate Coastal Hazards Across Entire Pacific

 

 

SANTA CRUZ, Calif. — The projected upsurge of severe El Niño and La Niña events will cause an increase in storm events leading to extreme coastal flooding and erosion in populated regions across the Pacific Ocean, according to a multi-agency study published today in Nature Geoscience. 

 

“This study significantly advances the scientific knowledge of the impacts of El Niño and La Niña,†said Patrick Barnard, USGS coastal geologist and the lead author of the study. “Understanding the effects of severe storms fueled by El Niño or La Niña helps coastal managers prepare communities for the expected erosion and flooding associated with this climate cycle.â€

 

http://www.usgs.gov/newsroom/article.asp?ID=4336#.VgA7ZX1H7qc

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Posted
  • Location: York
  • Weather Preferences: Long warm summer evenings. Cold frosty sunny winter days.
  • Location: York

A new book which has reviewed some 600 scientific papers on climate change. Is it a game changer!!

 

http://judithcurry.com/2015/09/20/new-book-doubt-and-certainty-in-climate-science/#more-19946

 

Its an e book which can be downloaded for free

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Posted
  • Location: Camborne
  • Location: Camborne

Model spread is not uncertainty

 

 

Comparison of a large set of climate model runs (CMIP5) with several observational temperature estimates. The thick black line is the mean of all model runs. The grey region is its model spread. The dotted lines show the model mean and spread with new estimates of the climate forcings. The coloured lines are 5 different estimates of the global mean annual temperature from weather stations and sea surface temperature observations.

It seems as if 2015 and likely also 2016 will become very hot years. So hot that you no longer need statistics to see that there was no decrease in the rate of warming, you can easily see it by eye now. Maybe the graph also looks less deceptive now that the very prominent super El Nino year 1998 is clearly no longer the hottest.

The "debate" is therefore now shifting to the claim that "the models are running hot". This claim ignores the other main option: that the observations are running cold. Even assuming the observations to be perfect, it is not that relevant that some years the observed annual mean temperatures were close to lower edge of the spread of all the climate model runs (ensemble spread). See comparison shown at the top.

Now that we do not have this case for some years, it may be a good moment to explain that the spread of all the climate model runs (ensemble spread) does not equal the uncertainty of these model runs. Because also some scientists seem to make this mistake, I thought this was worthy of a post. One hint is naturally that the words are different. That is for a reason.

 

http://variable-variability.blogspot.co.uk/2015/09/model-spread-is-not-uncertainty-nwp.html

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

Ice samples from Greenland, Russia provide clues to past, future climate change

 

Scientists have discovered evidence of carbonaceous aerosols -- organic dust -- transported from Asia and deposited in the Arctic over the last 450 years, according to a study. They have also found that increased levels of dust were being deposited during warmer periods when the Arctic Oscillation -- changes in the prevailing wind direction centred on the Atlantic -- was at its strongest.

 

http://www.sciencedaily.com/releases/2015/09/150928082152.htm?utm_source=twitterfeed&utm_medium=twitter&utm_campaign=Feed%3A+Cryonews+%28CryoNews%29

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