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  • Hurricanes « RealClimate
    classification procedure by condensing the Dvorak Technique to a few simple questions that can be answered by global nonprofessional users One of the main advantages of this approach is the inclusion of thousands of users instead of the 1 3 who would normally classify a TC image This allows the computation of measures of uncertainty in addition to a mean intensity Nearly 300 000 images encompassing all global TCs that formed from 1978 2009 will be classified 30 times each a feat that would take a dedicated team of twenty Dvorak trained experts about 12 years to complete Citizen scientists have already performed over 100 000 classifications since the project launch in September Once the project is complete a new dataset of global TC tracks and intensities will be made available to the community to contribute to our efforts to provide the best possible TC data record Interested readers are encouraged to learn more about and participate in the project at the cyclonecenter org website there are some FAQ on the project blog The CycloneCenter project is a collaboration between the Citizen Science Alliance NOAA National Climatic Data Center NCDC University of North Carolina at Asheville and the Cooperative Institute for Climate and Satellites CICS North Carolina References K R Knapp M C Kruk D H Levinson H J Diamond and C J Neumann The International Best Track Archive for Climate Stewardship IBTrACS Bull Amer Meteor Soc vol 91 pp 363 376 2010 http dx doi org 10 1175 2009BAMS2755 1 C Velden B Harper F Wells J L Beven R Zehr T Olander M Mayfield C Guard M Lander R Edson L Avila A Burton M Turk A Kikuchi A Christian P Caroff and P McCrone The Dvorak Tropical Cyclone Intensity Estimation Technique A Satellite Based Method that Has Endured for over 30 Years Bull Amer Meteor Soc vol 87 pp 1195 1210 2006 http dx doi org 10 1175 BAMS 87 9 1195 J A Knaff D P Brown J Courtney G M Gallina and J L Beven An Evaluation of Dvorak Technique Based Tropical Cyclone Intensity Estimates Wea Forecasting vol 25 pp 1362 1379 2010 http dx doi org 10 1175 2010WAF2222375 1 T L Olander and C S Velden The Advanced Dvorak Technique Continued Development of an Objective Scheme to Estimate Tropical Cyclone Intensity Using Geostationary Infrared Satellite Imagery Wea Forecasting vol 22 pp 287 298 2007 http dx doi org 10 1175 WAF975 1 C C Hennon Citizen scientists analyzing tropical cyclone intensities Eos Trans AGU vol 93 pp 385 387 2012 http dx doi org 10 1029 2012EO400002 Comments pop up 23 The IPCC report on extreme climate and weather events Filed under Climate Science Communicating Climate Hurricanes IPCC Reporting on climate rasmus 19 November 2011 The IPCC recently released the policy maker s summary SREX SPM on extreme weather and climate events The background for this report is a larger report that is due to be published in the near future and one

    Original URL path: http://www.realclimate.org/index.php/archives/category/climate-science/hurricanes/ (2016-02-13)
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  • IPCC « RealClimate
    accurate based on our assessment of their methodology They ignored our offer but now the time period of the bet has passed it s worth checking how it would have gone More References D M Smith S Cusack A W Colman C K Folland G R Harris and J M Murphy Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model Science vol 317 pp 796 799 2007 http dx doi org 10 1126 science 1139540 N S Keenlyside M Latif J Jungclaus L Kornblueh and E Roeckner Advancing decadal scale climate prediction in the North Atlantic sector Nature vol 453 pp 84 88 2008 http dx doi org 10 1038 nature06921 Comments pop up 45 Debate in the noise Filed under Climate Science Communicating Climate Instrumental Record IPCC Reporting on climate stefan 15 June 2015 Last week there was an international media debate on climate data which appeared to be rather surreal to me It was claimed that the global temperature data had so far shown a hiatus of global warming from 1998 2012 which was now suddenly gone after a data correction So what happened One of the data centers that compile the data on global surface temperatures NOAA reported in the journal Science on an update of their data Some artifacts due to changed measurement methods especially for sea surface temperatures were corrected and additional data of previously not included weather stations were added All data centers are continually working to improve their database and they therefore occasionally present version updates of their global series NASA data are currently at version 3 the British Hadley Centre data at version 4 There is nothing unusual about this and the corrections are in the range of a few hundredths of a degree see Figure 1 This really is just about fine details More Comments pop up 59 Global warming and unforced variability Clarifications on recent Duke study Filed under Climate modelling Climate Science Instrumental Record IPCC group 13 May 2015 Guest Commentary from Patrick Brown and Wenhong Li Duke University We recently published a study in Scientific Reports titled Comparing the model simulated global warming signal to observations using empirical estimates of unforced noise Our study seemed to generated a lot of interest and we have received many inquires regarding its findings We were pleased with some of coverage of our study e g here but we were disappointed that some outlets published particularly misleading articles e g here here and here Since there appears to be some confusion regarding our study s findings we would like to clarify some points see also MM4A s discussion More References P T Brown W Li E C Cordero and S A Mauget Comparing the model simulated global warming signal to observations using empirical estimates of unforced noise Sci Rep vol 5 pp 9957 2015 http dx doi org 10 1038 srep09957 Comments pop up 36 Older Entries Site Google Custom Search Recent Comments What is the best description

    Original URL path: http://www.realclimate.org/index.php/archives/category/climate-science/ipcc/ (2016-02-13)
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  • Oceans « RealClimate
    ones Fig 1 Sea level curves calculated by different research groups with various methods The curves show the sea level relative to the satellite era since 1992 Graph Klaus Bittermann All curves show the well known modern sea level rise but the exact extent and time evolution of the rise differ somewhat Up to about 1970 the new reconstruction of Hay et al runs at the top of the existing uncertainty range For the period from 1880 AD however it shows the same total increase as the current favorites by Church White Starting from 1900 AD it is about 25 mm less This difference is at the margins of significance the uncertainty ranges overlap More References C C Hay E Morrow R E Kopp and J X Mitrovica Probabilistic reanalysis of twentieth century sea level rise Nature vol 517 pp 481 484 2015 http dx doi org 10 1038 nature14093 Comments pop up 43 Diagnosing Causes of Sea Level Rise Filed under Climate Science Oceans eric 8 January 2015 Guest post by Sarah G Purkey and Gregory C Johnson University of Washington NOAA I solicited this post from colleagues at the University of Washington I found their paper particularly interesting because it gets at the question of sea level rise from a combination of ocean altimetry and density temperature salinity data This kind of measurement and calculation has not really been possible not at this level of detail until quite recently A key finding is that one can reconcile various different estimates of the contributions to observed sea level rise only if the significant warming of the deep ocean is accounted for There was a good write up in The Guardian back when the paper came out Eric Steig Sea leave rise reveals a lot about our changing climate A rise in the mean sea level can be caused by decreases in ocean density mostly reflecting an increase in ocean temperature this is steric sea level rise It can also be caused by an increase in ocean mass reflecting a gain of fresh water from land A third and smaller contribution to mean sea level is from glacial isostatic adjustment The contribution of glacial isostatic adjustment while small has a range of possible values and can be a significant source of uncertainty in sea level budgets Over recent decades very roughly half of the observed mean sea level rise is owing to changes in ocean density with the other half owing to the increased in ocean mass mostly from melting glaciers and polar ice sheets The exact proportion has been difficult to pin down with great certainty More References S G Purkey G C Johnson and D P Chambers Relative contributions of ocean mass and deep steric changes to sea level rise between 1993 and 2013 J Geophys Res Oceans vol 119 pp 7509 7522 2014 http dx doi org 10 1002 2014JC010180 Comments pop up 52 Older Entries Site Google Custom Search Recent Comments What is the best description

    Original URL path: http://www.realclimate.org/index.php/archives/category/climate-science/oceans/ (2016-02-13)
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  • Paleoclimate « RealClimate
    to be covered include how sensitivity is defined and whether it is even meaningful Spoiler yes it is what it means how it can be constrained what the different flavours signify etc There is an impressive list of attendees with a very diverse range of views on just about everything and so I am looking forward to very stimulating discussions More Comments pop up 26 The mystery of the offset chronologies Tree rings and the volcanic record of the 1st millennium Filed under Aerosols Climate Science Paleoclimate group 19 February 2015 Guest commentary by Jonny McAneney Volcanism can have an important impact on climate When a large volcano erupts it can inject vast amounts of dust and sulphur compounds into the stratosphere where they alter the radiation balance While the suspended dust can temporarily block sunlight the dominant effect in volcanic forcing is the sulphur which combines with water to form sulphuric acid droplets These stratospheric aerosols dramatically change the reflectivity and absorption profile of the upper atmosphere causing the stratosphere to heat and the surface to cool resulting in climatic changes on hemispheric and global scales Interrogating tree rings and ice cores Annually resolved ice core and tree ring chronologies provide opportunities for understanding past volcanic forcing and the consequent climatic effects and impacts on human populations It is common knowledge that you can tell the age of a tree by counting its rings but it is also interesting to note that the size and physiology of each ring provides information on growing conditions when the ring formed By constructing long tree ring chronologies using suitable species of trees it is possible to reconstruct a precisely dated annual record of climatic conditions Ice cores can provide a similar annual record of the chemical and isotopic composition of the atmosphere in particular volcanic markers such as layers of volcanic acid and tephra However ice cores can suffer from ambiguous layers that introduce errors into the dating of these layers of volcanic acid To short circuit this attempts have been made to identify know historical eruptions within the ice records such as Öraefajökull 1362 and Vesuvius AD 79 This can become difficult since the ice chronologies can only be checked by finding and definitively identifying tephra volcanic glass shards that can be attributed to these key eruptions sulphate peaks in the ice are not volcano specific Thus it is fundamentally important to have chronological agreement between historical tree ring and ice core chronologies The ice cores record the magnitude and frequency of volcanic eruptions with the trees recording the climatic response and historical records evidencing human responses to these events But they don t quite line up More Comments pop up 44 Can we make better graphs of global temperature history Filed under Climate Science Communicating Climate Instrumental Record Paleoclimate gavin 13 March 2014 I m writing this post to see if our audience can help out with a challenge Can we collectively produce some coherent properly referenced open source scalable

    Original URL path: http://www.realclimate.org/index.php/archives/category/climate-science/paleoclimate/ (2016-02-13)
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  • Sun-earth connections « RealClimate
    lapses and conflicts of interest for the sake of scientific advancement though far too many similar post hoc justifications have been used to excuse horrific unethical practices for this to be remotely defendable Unfortunately the evidence from the emails and the work itself completely undermines that argument because the work and the motivation behind it are based on a scientific fallacy More Comments pop up 56 The most popular deceptive climate graph Filed under Climate Science Communicating Climate Instrumental Record skeptics Sun earth connections stefan 8 December 2014 The World Climate Widget from Tony Watts blog is probably the most popular deceptive image among climate skeptics We ll take it under the microscope and show what it would look like when done properly So called climate skeptics deploy an arsenal of misleading graphics with which the human influence on the climate can be down played here are two other examples deconstructed at Realclimate The image below is especially widespread It is displayed on many climate skeptic websites and is regularly updated The World Climate Widget of US climate skeptic Anthony Watts with our explanations added The original can be found on Watts blog What would a more honest display of temperature CO 2 and sunspots look like More Comments pop up 217 Simple physics and climate Filed under Climate modelling Climate Science Greenhouse gases Sun earth connections rasmus 12 November 2013 No doubt our climate system is complex and messy Still we can sometimes make some inferences about it based on well known physical principles Indeed the beauty of physics is that a complex systems can be reduced into simple terms that can be quantified and the essential aspects understood A recent paper by Sloan and Wolfendale 2013 provides an example where they derive a simple conceptual model of how the greenhouse effect works from first principles They show the story behind the expression saying that a doubling in CO 2 should increase the forcing by a factor of 1 log 2 log CO2 I have a fondness for such simple conceptual models e g I ve made my own attempt posted at arXiv because they provide a general picture of the essence of course their precision is limited by their simplicity More References T Sloan and A W Wolfendale Cosmic rays solar activity and the climate Environ Res Lett vol 8 pp 045022 2013 http dx doi org 10 1088 1748 9326 8 4 045022 Comments pop up 35 A review of cosmic rays and climate a cluttered story of little success Filed under Climate Science Instrumental Record Sun earth connections rasmus 25 December 2012 A number of blogs were excited after having leaked the second order draft of IPCC document which they interpreted as a game changing admission of enhanced solar forcing However little evidence remains for a link between galactic cosmic rays GCR and variations in Earth s cloudiness Laken et al 2012 recently provided an extensive review of the study of the GCR and Earth s

    Original URL path: http://www.realclimate.org/index.php/archives/category/climate-science/sun-earth-connections/ (2016-02-13)
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  • Communicating Climate « RealClimate
    Science meeting on the planet There is a lot of great science that will be freely streamed via AGU On Demand registration required and there ll be a lot of commentary using the hashtag AGU15 Many posters will be available online too A few highlights have already been discussed by Victor Venema related to the surface temperature station datasets but there ll be much more on offer if you dig deeper As the week goes on we ll link to anything good we see and we ll be happy to host any commentaries that anyone has on specific climate sessions or talks Happy conferencing Comments pop up 73 Hiatus or Bye atus Filed under Climate Science Communicating Climate Instrumental Record Reporting on climate skeptics group 26 November 2015 Guest commentary by Stephan Lewandowsky James Risbey and Naomi Oreskes The idea that global warming has stopped has long been a contrarian talking point This framing has found entry into the scientific literature and there are now numerous articles that address a presumed recent pause or hiatus in global warming Moreover the hiatus also featured as an accepted fact in the latest IPCC report AR5 Notwithstanding its widespread use in public and apparent acceptance in the scientific community there are reasons to be skeptical of the existence of a hiatus or pause in global warming Ed see also this previous post We have examined this issue in a series of three recent papers which have converged on the conclusion that there is not now and there never has been a hiatus or pause in global warming More Comments pop up 92 Reports of our demise Filed under Climate Science Communicating Climate gavin 23 November 2015 have of course been greatly exaggerated But we are having some issues with our domain name The back story is perhaps interesting to others so here is quick summary of the situation Update The account details have been restored and the domains renewed We should be back to normal in a couple of days More Comments pop up 53 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn What is the best description of the greenhouse effect Jack Barrett With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the

    Original URL path: http://www.realclimate.org/index.php/archives/category/communicating-climate/ (2016-02-13)
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  • Reporting on climate « RealClimate
    data of previously not included weather stations were added All data centers are continually working to improve their database and they therefore occasionally present version updates of their global series NASA data are currently at version 3 the British Hadley Centre data at version 4 There is nothing unusual about this and the corrections are in the range of a few hundredths of a degree see Figure 1 This really is just about fine details More Comments pop up 59 Thoughts on 2014 and ongoing temperature trends Filed under Climate Science El Nino Instrumental Record Reporting on climate gavin 22 January 2015 Last Friday NASA GISS and NOAA NCDC had a press conference and jointly announced the end of year analysis for the 2014 global surface temperature anomaly which in both analyses came out top As you may have noticed this got much more press attention than their joint announcement in 2013 which wasn t a record year In press briefings and interviews I contributed to I mostly focused on two issues that 2014 was indeed the warmest year in those records though by a small amount and the continuing long term trends in temperature which since they are predominantly driven by increases in greenhouse gases are going to continue and hence produce on a fairly regular basis continuing record years Response to these points has been mainly straightforward which is good if sometimes a little surprising but there have been some interesting issues raised as well More Comments pop up 308 Ten Years of RealClimate Where now Filed under Climate Science Communicating Climate Reporting on climate group 14 December 2014 The landscape for science blogging the public discourse on climate and our own roles in the scientific community have all changed radically over the last 10 years Blogging is no longer something that stands apart from professional communications the mainstream media or new online start ups The diversity of voices online has also increased widely scientists blogging and interacting directly with the public via Twitter and Facebook are much more prevalent than in 2004 The conversations have also changed and for the most part have become more nuanced And a bunch of early career researchers with enthusiasm time to spare and things to say have morphed into institute directors and administrators with lots of new pressures Obviously blogging frequency has decreased in the last year or so in response to these pressures and this raises the question where does RealClimate go now More Comments pop up 42 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of

    Original URL path: http://www.realclimate.org/index.php/archives/category/communicating-climate/reporting-on-climate/ (2016-02-13)
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  • Extras « RealClimate
    known by the cryptic name CMIP5 It turned out that the results were ok but we had made an error when reading and processing the model output The particular climate model that initially gave the strange results had used a different calendar set up to the previous models we had examined More Comments pop up 12 A new European report on climate extremes is out Filed under Climate impacts Climate Science Communicating Climate Reporting on climate Reviews rasmus 26 October 2013 A new report on extreme climate events in Europe is just published Extreme Weather Events in Europe preparing for climate change adaptation It was launched in Oslo on October 24th by the Norwegian Academy of Science and Letters and the report is now available online Front cover of Extreme Weather Events in Europe preparing for climate change adaptation What s new The new report provides information that is more specific to Europe than the SREX report from the Intergovernmental Panel on Climate Change IPCC and incorporate phenomena that have not been widely covered It provides some compelling information drawn from the insurance industry and indeed a representative from Munich Re participated in writing this report There is also material on convective storms hail lightening and cold snaps and the report provides a background on extreme value statistics risk analysis impacts and adaptation More Comments pop up 90 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn What is the best description of the greenhouse effect Jack Barrett With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies

    Original URL path: http://www.realclimate.org/index.php/archives/category/extras/ (2016-02-13)
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