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Post by marchesarosa on Jun 24, 2011 9:53:40 GMT 1
Tropical Storm Beatriz – the six hour “shorty”Posted on June 23, 2011 by Anthony Watts 50 years ago, we’d never have counted this as a tropical storm. As outlined recently in New peer reviewed study: Surge in North Atlantic hurricanes due to better detectors, not climate change, its the technology that enables counting storms that would not have been counted before. Ditto for tornadoes and sunspots.... ...a quick drop in strength over six hours and transformed Beatriz from a strong tropical storm to a weak tropical depression... more wattsupwiththat.com/2011/06/23/tropical-storm-beatriz-the-six-hour-shorty/
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Post by marchesarosa on Jun 27, 2011 9:08:05 GMT 1
Global hurricane activity at historical record lows: new paperPosted on June 26, 2011 by Ryan Maue During the past 6-years since Hurricane Katrina, global tropical cyclone frequency and energy have decreased dramatically, and are currently at near-historical record lows. According to a new peer-reviewed research paper accepted to be published, only 69 tropical storms were observed globally during 2010, the fewest in almost 40-years of reliable records. Furthermore, when each storm’s intensity and duration were taken into account, the total global tropical cyclone accumulated energy (ACE) was found to have fallen by half to the lowest level since 1977. In his new paper “Recent historically low global tropical cyclone activity”, Dr. Ryan Maue, a meteorologist from Florida State University, examined the last 40-years of global hurricane records and found strikingly large variability in both tropical cyclone frequency and energy from year-to-year. Since 2007, global tropical cyclone activity has decreased dramatically and has continued at near-historical low levels. Indeed, only 64 tropical cyclones were observed globally in the 12-months from June 2010 – May 2011, nearly 23-storms below average obliterating the previous record low set in 1977...... www.coaps.fsu.edu/%7Emaue/tropical/global_running_ace.jpgmore here wattsupwiththat.com/2011/06/26/global-hurricane-activity-at-historical-record-lows-new-paper/
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Post by marchesarosa on Jun 30, 2011 16:19:14 GMT 1
Judith Curry's views on attributing the cause of extreme weather to anthropogenic global warming. judithcurry.com/2011/06/30/climate-change-extreme-weather-linked-at-last/#more-3896Judith Curry is chair of Georgia Institute of Technology’s School of Earth and Atmospheric Sciences. Here is the statement provided to the recent Yale360 Forum on this topic: The substantial interest in attributing extreme weather events to global warming seems rooted in the perceived need for some sort of a disaster to drive public opinion and the political process in the direction of taking action on climate change. However, attempts to attribute individual extreme weather events, or collections of extreme weather events, may be fundamentally ill-posed in the context of the complex climate system, which is characterized by spatiotemporal chaos. There are substantial difficulties and problems associated with attributing changes in the average climate to natural variability versus anthropogenic forcing, which I have argued are oversimplified by the IPCC assessments. Attribution of extreme weather events is further complicated by their dependence on weather regimes and internal multi-decadal oscillations that are simulated poorly by climate models.
I am unconvinced by any of the arguments that I have seen that attributes a single extreme weather event, a cluster of extreme weather events, or statistics of extreme weather events to anthropogenic forcing. Improved analysis of the attribution of extreme weather events requires a substantially improved and longer database of the events. Interpretation of these events in connection with natural climate regimes such as El Nino is needed to increase our understanding of the role of natural climate variability in determining their frequency and intensity. Improved methods of evaluating climate model simulations of distributions of extreme event intensity and frequency in the context of natural variability is needed before any confidence can be placed in inferences about the impact of anthropogenic influences on extreme weather events.
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Post by marchesarosa on Jul 14, 2011 13:03:55 GMT 1
The 2010 Summer Heat Wave of Western Russia
Reference Dole, R., Hoerling, M., Perlwitz, J., Eischeid, J., Pegion, P., Zhang, T., Quan, X.-W., Xu, T. and Murray, D. 2011.
Was there a basis for anticipating the 2010 Russian heat wave? Geophysical Research Letters 38: 10.1029/2010GL046582.
Background
The authors write that “the 2010 summer heat wave in western Russia was extraordinary, with the region experiencing the warmest July since at least 1880 and numerous locations setting all-time maximum temperature records.” And as a result, they say that “questions of vital societal interest are whether the 2010 Russian heat wave might have been anticipated, and to what extent human-caused greenhouse gas emissions played a role.”
What was done
In broaching this question, Dole et al. used both climate model simulations and observational data “to determine the impact of observed sea surface temperatures, sea ice conditions and greenhouse gas concentrations.”
What was learned
The nine U.S. researchers determined that “analysis of forced model simulations indicates that neither human influences nor other slowly evolving ocean boundary conditions contributed substantially to the magnitude of the heat wave.” In fact, they say that the model simulations provided “evidence that such an intense event could be produced through natural variability alone.” Similarly, on the observation front, they state that “July surface temperatures for the region impacted by the 2010 Russian heat wave show no significant warming trend over the prior 130-year period from 1880-2009,” noting, in fact, that “a linear trend calculation yields a total temperature change over the 130 years of -0.1°C.” In addition, they indicate that “no significant difference exists between July temperatures over western Russia averaged for the last 65 years (1945-2009) versus the prior 65 years (1880-1944),” and they state that “there is also no clear indication of a trend toward increasing warm extremes.” Last of all, they say that although there was a slightly higher variability in temperature in the latter period, the increase was “not statistically significant.”
What it means
“In summary,” to quote Dole et al., “the analysis of the observed 1880-2009 time series shows that no statistically significant long-term change is detected in either the mean or variability of western Russia July temperatures, implying that for this region an anthropogenic climate change signal has yet to emerge above the natural background variability.” Thus, they say their analysis “points to a primarily natural cause for the Russian heat wave,” noting that the event “appears to be mainly due to internal atmospheric dynamical processes that produced and maintained an intense and long-lived blocking event,” adding that there are no indications that “blocking would increase in response to increasing greenhouse gases.”
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Don't let this "research" prevent Louise et al including this famous Russian "extreme weather event" episode on the list of misdemeanors due to Anthropogenic Global Warming.
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Post by marchesarosa on Jul 15, 2011 1:44:05 GMT 1
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Post by marchesarosa on Aug 3, 2011 16:42:29 GMT 1
judithcurry.com/2011/08/03/on-the-attribution-of-flood-peaks/#more-4353On the attribution of flood peaksAugust 3, 2011 by Judith Curry The hypothesized link between a warming climate and increased frequency and magnitude of floods goes something like this: a warmer climate is associated with more water vapor in the atmosphere, which means more rainfall and more clouds. Is there any observational support for this link? A series of papers on this subject have been published by Gabriele Villarini at Princeton University. Two of the papers related to the U.S. are highlighted here. Flood peak distributions for the eastern United StatesGabriele Villarini and James Smith Pielke Jr. cites the following from the paper’s conclusions: Only a small fraction of stations exhibited significant linear trends. For those stations with trends, there was a split between increasing and decreasing trends. No spatial structure was found for stations exhibiting trends. There is little indication that human‐induced climate change has resulted in increasing flood magnitudes for the eastern United States.Examining Flood Frequency Distributions in the Midwest U.S.Gabriele Villarini, James Smith, Mary Lynn Baeck, Wiltoid Krajewski CO2Science provides the following summary of the paper: What was learned The four U.S. researchers report that in the vast majority of cases where streamflow changes were observed, they were “associated with change-points (both in mean and variance) rather than monotonic trends,” and they indicate that “these non-stationarities are often associated with anthropogenic effects.” But rather than increases in anthropogenic CO2 emissions, they cite such things as “changes in land use/land cover, changes in agricultural practice, and construction of dams and reservoirs.”
What it means Based on their findings, and, as they note, “in agreement with previous studies” they conclude that “there is little indication that anthropogenic climate change has significantly affected the flood frequency distribution for the Midwest U.S.” And as they make doubly clear in the abstract of their paper, they say that “trend analyses do not suggest an increase in the flood peak distribution due to anthropogenic climate change.”JC comments: Villarini’s analysis and interpretation seems pretty compelling to me, I like the methodology. So what is wrong with the picture that Kevin Trenberth (and others) have been painting (besides the fact that they don’t seem to have looked at actual flood data)? An increase in atmospheric water vapor associated with warmer temperatures doesn’t necessarily increase rainfall nor is it necessary that an increase in rainfall is distributed spatiotemporally to produce increased floods. It seems that whatever signal that might be found for an increase in floods from global warming is swamped by changes in land use and river engineering. -------- See Climate Etc for the abstracts of both papers.
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Post by marchesarosa on Aug 3, 2011 16:48:28 GMT 1
Another one for the alarmists and the BBC to ignore.
And remember, flood damage is an entirely different matter from changes in the incidence or magnitude of floods.
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Post by marchesarosa on Aug 3, 2011 17:04:16 GMT 1
Commentators note that the holding of extra water vapour by warmer air does not mean that it falls as rain. Only if the temperature falls does the rain fall, too.
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Post by marchesarosa on Aug 3, 2011 18:39:13 GMT 1
Reading this sort of comment is what makes my day!
From "HFL" on the Climate Etc thread linked above
As you point out Judith, the hypothesized link between warming and increased flooding stems from the reasoning, based on the Clausius-Clapeyron equation, that warming will lead to an enhancement or acceleration of the hydrological cycle. Notably, Trenberth, Karl, Groisman, and others have also argued that the observed increases in precipitation over the past century, which have been documented as occurring disproportionately in the upper tail of the distribution (i.e., “heavy and extreme” precipitation) must, therefore, be manifesting itself in increases in peak streamflow. Over the past decade, a number of hydrologists at the USGS, the agency responsible for gauging the nation’s streams, have analyzed trends in daily streamflow across the country. They have uniformly used records from stations minimally affected by such confounding human activities as regulation and diversions, so as to reflect primarily a climate signal, and have also investigated changes in the entire distribution of flows from the annual minimum to the annual maximum. So they have been able to assess where in the distribution of streamflows trends have been occurring.
Their results, and those of other hydrologists outside USGS, have been consistent and very telling. All have found increases in flow over the past century, in agreement with increases in precipitation. However, those increases have been occurring in the low to moderate range of flows, from the annual minimum through the annual median. More significantly, very few stations have experienced trends in annual maximum flow and, among those that have, there have been as many decreasing trends as increasing. Thus, it appears that the observed increases in what has been termed heavy and extreme precipitation, i.e., defined by Karl et al. in their 1995 Nature paper as >50mm day, has been sufficient to increase low to average streamflow, but not sufficient to increase peak streamflow.
To understand this association better, USGS also evaluated the seasonality of the trends. Most studies of precipitation trends have indicated that the increases are occurring primarily in autumn and early winter. Across the U.S., early autumn is the season when streamflows are at their annual minimum, with moderate flows typically occurring in late autumn to early winter. So the observed increase in precipitation, even in the heavy and extreme category, is occurring at the time of annual minimum streamflow. Thus, at least to date, the nation has benefited from having more water coursing through its rivers and streams, and has not had to pay a flood penalty for it.
In all likelihood, the apparent conundrum between increasing “extreme” precipitation and the lack of increasing floods can be traced to the commonly used definition of “extreme” precipitation. A 50mm per day event is not a flood generator unless a basin is already at saturation. Most significant flooding in the U.S. occurs in response to multiday rainfall episodes or after weeks or months of persistent rainfall. Perhaps a 50mm per day rainfall threshold has some significance in terms of meteorological extremes but, in terms of flood hydrometeorology and hydroclimatology, it is does not.
For more details on this issue see: Lins and Slack, GRL, 1999; Lins and Slack, Phys. Geog., 2005; McCabe and Wolock, GRL, 2002; Small et al., GRL, 2006.
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Post by StuartG on Aug 3, 2011 19:32:35 GMT 1
Re: Climate Change: Public Skeptical, Scientists Sure 01 Aug 2011 12:38 #13 www.sciencefile.org/system/forum/Climate-Change/168309-Climate-Change-Public-Skeptical-Scientists-Sure.html#168836 nordsider ( User ) OFFLINE Lab Manager Posts: 595 "In the U.S., in my home city of Chicago, the rain fall on July 23 rd was 6.68 inches, that is the biggest single-day rainfall since records began in 1871. And on that day the bridges over the river running through the city prevented boats from passing beneath their structures because of the river's high water level . . . and during the worst Texas drought since record-keeping began 116 years ago. . . or, Kansas heat wave has killed 2,000 cattle. . . Almost half the USA, including much of the Midwest, Northeast and all the way down the Mississippi River Valley to New Orleans, has an above-average risk for spring flooding, according to a forecast issued by the National Weather Service on 3/18/2011." An indicator of AGW? Doubtful. Surely, before blaming the World for the misfortune that hit Chicago, look more locally. "Chicagoans deserve clean air" "2:30 p.m. CDT, July 28, 2011 Last week, Chicago experienced "orange alert" air pollution days for ozone pollution (or "smog"), signaling to residents that sensitive populations, such as people with lung or heart disease, older adults and children, may experience adverse health effects as a result of this pollution. Coal-fired power plants are a big part of the problem, emitting tons of dangerous smog-forming and fine particle "soot" pollution into our air each year, and putting my health and the health of my family and friends at risk." A letter to the Chicago Tribune. www.chicagotribune.com/news/opinion/letters/chi-110728sugent_briefs,0,2557400.story Comment: So there are large quantities of aerosols. [locally] ---- "Chicago flooding Q&A: Freak storm, aging sewers and Chicago's topography lead to flooding woes" 11:58 a.m. CDT, July 28, 2011 "Q: Why did my basement flood?" "A: There are a number of reasons, starting with the sheer amount of rain that fell Saturday. The 6.86 inches was the most in one day since Chicago began keeping records in 1870. Since much of the area was once a swamp, it is naturally prone to flooding. We also have built and paved over many areas that once absorbed stormwater, leaving little choice but to flush it into sewers." www.chicagotribune.com/news/local/ct-met-flood-water-management-20110728,0,6418041.story Comment: This is just a start, for illustration. The point being is to look nearer to home when these things happen. Only after that look away elsewhere. ---- Industrial Pollution The Electronic Encyclopedia of Chicago www.encyclopedia.chicagohistory.org/pages/638.htmlComment: perhaps because there is less pollution nowadays, the local climate is reverting to its old ways. If buildings are founded on swampland it is reasonable to expect trouble in the future. We've seen that in this country. That ain't climate change that's stupidity. StuartG
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Post by StuartG on Aug 13, 2011 0:50:03 GMT 1
"Storm tracks are heading for the poles, satellite data suggests" By Scott K. Johnson | Published about 5 hours ago "Mid-latitude storm tracks are major weather patterns that account for the majority of precipitation in the globe's middle latitudes, which includes most of the heavily populated areas of North America, Eurasia, and Australia. Due to atmospheric circulation and the dynamics of weather systems, these bands of low pressure form repeatedly in the same locations. Apart from being meteorologically important, they’re also major players on the climate scene—clouds in these regions are responsible for reflecting much of the incoming solar radiation that is bounced back to space before penetrating Earth’s atmosphere. " "Many climate models have predicted that the positions of these storm tracks would slowly migrate toward the poles, but so far this trend had not been detected. However, analysis of 25 years worth of data from the International Satellite Cloud Climatology Project now indicates that this shift is probably already taking place. " "The International Satellite Cloud Climatology Project (or ISCCP) operates a network of geostationary and polar orbiting satellites that have been collecting data on clouds since 1983. A team of researchers carefully analyzed data for Northern and Southern Hemisphere storm tracks in the Atlantic and Pacific Oceans to look for trends in storm track positions. (The Indian Ocean could not be included because of issues with satellite coverage.) The results indicated a slight poleward shift of the storm tracks." ...continues Climate Dynamics, 2011. DOI: not yet available (About DOIs). arstechnica.com/science/news/2011/08/satellite-data-appears-to-confirm-model-predictions-of-storm-track-behavior.arsComment: This sounds very flakey. "The Indian Ocean could not be included" Wiki states "The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface" That's a large bit of water to leave out.
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Post by marchesarosa on Aug 13, 2011 15:53:32 GMT 1
"A team of researchers carefully analyzed data.."
I love the inclusion of the word "carefully", stu!
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Post by marchesarosa on Aug 13, 2011 15:55:26 GMT 1
I suppose they are a bit short of scary stuff to frighten the kiddies with, what with hurricanogeddon not materialising as predicted, so its a poleward shift of summat else instead.
Oooh, I am so scared!
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Post by StuartG on Aug 14, 2011 0:07:20 GMT 1
Herald-Tribune "Pacific may hold key to Atlantic hurricanes" Published: Friday, August 12, 2011 at 6:01 p.m. By Kate Spinner [four pages] "In 2010, global hurricane activity hit a record low. But the Atlantic saw its third-busiest hurricane season on record, underscoring a trend that has emerged since the mid-1990s." .... "In 2010, global hurricane activity hit a record low. But the Atlantic saw its third-busiest hurricane season on record, underscoring a trend that has emerged since the mid-1990s." .... "Hurricanes can cause terrible destruction when they hit land. But, Maue said, they are vitally important for balancing heat energy in the oceans." .... "Scientists theorize that the Pacific and the Atlantic both go through cool and warm phases that last decades. The Atlantic is in a warm phase and the Pacific may be moving toward a cool phase." .... "Most climate scientists now believe a warmer Earth will translate into fewer hurricanes, or roughly the same amount. Some theorize that the storms will likely be more intense." .... "High in the atmosphere, the temperature over the tropics is about the same around the globe. If the Atlantic surface temperatures are warmer than the air above, the atmosphere becomes unstable and conducive for tropical storms and hurricanes." .... "When the Atlantic is warm, he said, its warm tropical waters tend to move farther north. The tropical water is warmer, but it is also saltier and more dense. The salinity causes the water to sink and get transported by cold ocean currents to the central tropical Pacific, where it loses its salinity and upwells as cold bouyant water." "Klotzbach said his mentor, William Gray, has another theory: El Niño transports heat energy from the eastern hemisphere to the western hemisphere. Since the Atlantic is already warmer than normal, that energy transfer is not necessary." .... www.heraldtribune.com/article/20110812/ARTICLE/110819861/2055/NEWS?p=4&tc=pgComment: After all that lot, we seem no further forward. That's all well and fair enough. It points up more 'known unknowns'. StuartG
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Post by marchesarosa on Aug 19, 2011 18:56:59 GMT 1
A new research study shows that overall global tropical cyclone activity has decreased to historically low levels during the past 5 years Geophysical Research Letters, doi:10.1029/2011GL047711, 2011 dx.doi.org/10.1029/2011GL047711Title: Recent historically low global tropical cyclone activity Author: Ryan N. Maue: Center for Ocean and Atmosphere Studies, Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida, USA
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