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Wednesday, 1 February 2012
US Winter Temperatures 1990-2011, by state
Here are winter temperatures for the 48 contiguous states from 1990 to 2011, plotted from NCDC (alphabetical order). Draw your own conclusions. Click to see full-size images (as with all my posts).
Sunday, 29 January 2012
Warming Winters? Meteorologist Paul Douglas' disconnect with reality.
The Minneapolis Star Tribune warns "Warmer winters bring tick-infested springs"
Apart from a downward tick for 2001, average winter temperatures have declined since 1998 (the peak). There's even a statistical downward trend since 1990. Focus in on Minneapolis-St.Paul, 1998-2011:
Other cities and towns in Minnesota show a similar trend from 1990, with pronounced cooling since 1998. The NCDC chart shows a downward trend of -0.88°F (-0.49°C) per decade, a whopping 8.8°F (-4.9°C) per century, the Minneapolis-St.Paul data an almost incredible 63.1°F (35°C) per century.
Where has Mr. Douglas been the last two decades, particularly since 1998? More to the point, where does he get his data to support his comment? Who is this Paul Douglas? Wikipedia knows - it seems he's an (ex-) TV weatherman, columnist and blogger. The Wiki page soon reveals something rather relevant :
As for Mr. Douglas' "steep reduction in Arctic air that was common even 20 or 30 years ago", have a look at "Arctic warming, increasing snow cover and widespread boreal winter cooling":
UPDATE 30th Jan. 2012
The Hufffington Post (such a goldmine of unbiased opinion!) says "On Climate Change, Weathercasters May Be Misguiding Their Viewers"
UPDATE 6th Feb. 2011
I found I'd used a GISS dataset for an entirely different Minneapolis for my original chart (should've spotted the different lat/lon - silly me!), so to save time sorting THAT out I've substituted the NCDC plot for Minneapolis-St.Paul for the relevant 1998-2011 period.I've altered the text to suit - If anything it reinforces my point.
UPDATE 12th Feb. 2011
On his his Star Tribune blog is a "Send Paul a question" link, so I've done just that, and here it is:
In Minnesota, black-legged ticks have expanded their territory since 2007. More people live in wooded areas where ticks thrive, more mice and other rodents that carry Lyme disease survive warmer winters, and more ticks "hitchhike" on birds and humans.Then follows some statistics about tick-borne disease (including the nasty "Lyme disease"), and the increasing prevalence of ticks in Minnesota, which I don't dispute. However, at the end we get a (second) quote from meteorologist Paul Douglas:
Winters in Minnesota have grown milder since 1998, Douglas said, with a steep reduction in Arctic air that was common even 20 or 30 years ago. "It's a slow-motion evolution," he said.That "grown milder since 1998" is precise and checkable so let's do it, starting with NOAA's National Climatic Data Center's data for Minnesota:
 |
| NCDC Winter temperatures for Minnesota, 1990-2011 |
Apart from a downward tick for 2001, average winter temperatures have declined since 1998 (the peak). There's even a statistical downward trend since 1990. Focus in on Minneapolis-St.Paul, 1998-2011:
 |
| NCDC Winter Temperatures for Minneapolis-St.Paul 1998-2011 |
Other cities and towns in Minnesota show a similar trend from 1990, with pronounced cooling since 1998. The NCDC chart shows a downward trend of -0.88°F (-0.49°C) per decade, a whopping 8.8°F (-4.9°C) per century, the Minneapolis-St.Paul data an almost incredible 63.1°F (35°C) per century.
Where has Mr. Douglas been the last two decades, particularly since 1998? More to the point, where does he get his data to support his comment? Who is this Paul Douglas? Wikipedia knows - it seems he's an (ex-) TV weatherman, columnist and blogger. The Wiki page soon reveals something rather relevant :
Douglas regularly writes and speaks about global warming and is critical of those who say that it is not occurring or is not caused by human actions.I write about global warming and I'm critical of those who say that something is occurring (warmer winters in Minnesota) when it's not. Mr. Douglas thinks Global Warming "deniers" are "immoral" ("Paul Douglas: 'I'm a recovering Republican, and I don't recognize my party any more"). I think those who tell the opposite of the truth are immoral.
As for Mr. Douglas' "steep reduction in Arctic air that was common even 20 or 30 years ago", have a look at "Arctic warming, increasing snow cover and widespread boreal winter cooling":
Abstract
The most up to date consensus from global climate models predicts warming in the Northern Hemisphere (NH) high latitudes to middle latitudes during boreal winter. However, recent trends in observed NH winter surface temperatures diverge from these projections. For the last two decades, large-scale cooling trends have existed instead across large stretches of eastern North America and northern Eurasia. We argue that this unforeseen trend is probably not due to internal variability alone. Instead, evidence suggests that summer and autumn warming trends are concurrent with increases in high-latitude moisture and an increase in Eurasian snow cover, which dynamically induces large-scale wintertime cooling. Understanding this counterintuitive response to radiative warming of the climate system has the potential for improving climate predictions at seasonal and longer timescales."For the last two decades" - I nearly ran out of fingers, but I'm pretty sure Mr. Douglas' 1998 is in there somewhere. Who's the "denier" now?
UPDATE 30th Jan. 2012
The Hufffington Post (such a goldmine of unbiased opinion!) says "On Climate Change, Weathercasters May Be Misguiding Their Viewers"
"If you look at the stats over the past five or six years, the public's belief that global warming is a serious problem, or is even happening, is declining," said Daniel Souweine, co-founder of the nonprofit Citizen Engagement Lab. In fact, nearly 40 percent of Americans are not convinced that the earth is heating up, according to the latest Pew Research Center poll.
"We think that's a result of the fact that they're not getting the right kind of information about what the science says," Souweine told The Huffington Post.We've proof that one, in particular, isn't giving the "right kind of information", as I've shown graphically.
UPDATE 6th Feb. 2011
I found I'd used a GISS dataset for an entirely different Minneapolis for my original chart (should've spotted the different lat/lon - silly me!), so to save time sorting THAT out I've substituted the NCDC plot for Minneapolis-St.Paul for the relevant 1998-2011 period.I've altered the text to suit - If anything it reinforces my point.
UPDATE 12th Feb. 2011
On his his Star Tribune blog is a "Send Paul a question" link, so I've done just that, and here it is:
A few weeks ago, you were quoted in a Star Tribune article on ticks in Minnesota:
"Winters in Minnesota have grown milder since 1998, Douglas said, with a steep reduction in Arctic air that was common even 20 or 30 years ago. "It's a slow-motion evolution," he said."
http://www.startribune.com/local/east/137802778.html
I'm interested in temperature trends, and often use the NCDC "Climate At A Glance" page to check trends for the US. However, using the form for Minnesota http://www.ncdc.noaa.gov/oa/climate/research/cag3/mn.html to plot winter temps since 1998 shows them to have been declining. I wonder if you could point me to a source that shows the opposite?I'll let you know if I get a response.
Saturday, 21 January 2012
The Footprint of El Niño - South Pacific Sea level
I've mentioned the intermittent effect of El Niño on South Pacific sea level in several posts. How and why does this part of the ENSO cycle affect sea level?
The island of Majuro, in the Marshall Islands reflects this trend particularly well. The opposite La Niña effect, though present, is not so well illustrated. Using data from an earlier gauge maintained by the University of Hawaii, and the later SEAFRAME gauge installed in 1993 by the National Tidal Centre based in Adelaide, Australia, I've been able to reconstruct a history of sea level at Majuro Atoll from 1978 to 2011.
For charts for Majuro and other Pacific Islands, including Tuvalu and Kiribati, see my reference page "South Pacific Sea Level 2011".
Here's a table of El Niño years. Those from 1969 to 2010 are clearly represented on the Majuro chart. The 1982-3 and 1997-8 El Niños were particularly strong events, and I've highlighted them in red
On the other (eastern) side of the Pacific, continuous long-term records are difficult to find, but that for Monterey, California illustrates the opposite effects quite well, although earlier El Niño years aren't quite so clearly defined.
Not much sign of the 1972-1973 and 1976-1977 El Niños, but the later events are all represented, though to varying degrees. Most of the west and south-west Pacific islands show the "El Niño" effect to differing degrees, but Tuvalu has become the "poster child" of the Global Warming scenario, so it's worthwhile reproducing my reconstruction for that island, covering 1977-2011.
The linear trend shows a value of 0.28 mm/month, which translates to 3.36 mm/year. However, the effect of the El Niños is to pull the trend line down progressively from right to left; it's always below the 13-month running mean (in red), more so on the left. A simple way to eliminate the negative effect of the El Niño "spikes" on the trend is to remove them from the data. However, this is not as easy as it sounds; there's a clear (approximately) annual cycle, illustrated by the sharp upward spikes. These "king tides" usually occur in late February or early March, occasionally as late as April, and their timing is due to the "lining up" of the tidal effects of both moon and sun. The all-time peak was in February 2006 (very clear on the graph), and despite dire predictions, hasn't yet been surpassed.
An Australian newspaper dispatched a team to Tuvalu in February 2011 to document what was expected to an all-time record "king tide". However, nature being as quirky as ever, organised things so that they'd already "missed the boat" (a metaphor becomes a bad pun!) as the highest tide had already occurred the previous month; indeed the February peak was lower than both January and March peaks. That and the fact that the January peak was no record, produced a "non-event" and no follow-up report was published.
However, I digress - removing the El Niño "spikes" must be done with care if an opposite upward bias is to be avoided. One way round this is to use annual data so the monthly cycle is not a problem, though it effectively removes more data. I'll be following up with a detailed analysis of late-20th century sea level rise at Tuvalu.
Data Sources
Marshall Islands (Majuro): Permanent Service for Mean Sea Level and South Pacific Sea Level and Climate Monitoring Project
Monterey: Permanent Service for Mean Sea Level
Tuvalu (Funafuti): Permanent Service for Mean Sea Level and South Pacific Sea Level and Climate Monitoring Project
The primary cause of anomalous ocean conditions is the El Niño/Southern Oscillation (ENSO) in the equatorial Pacific Ocean. Westward winds normally maintain slightly higher water levels in the western Pacific relative to the eastern Pacific. Every three to five years, in a non-periodic pattern, the winds weaken and water levels in the western Pacific drop below normal. The southern equatorial current is weakened and water temperatures in the eastern Pacific rise. This condition is known as El Niño. The opposite condition, known as La Niña, occurs when westward equatorial winds are unusually strong and water levels in the western Pacific become anomalously high. The south equatorial current strengthens, accompanied by below normal water temperatures in the eastern Pacific.Boiled down, in terms of the effect on sea level, is that levels in the western and south-western Pacific tend to drop, often significantly, during El Niño years, while those in the east tend to rise.
The island of Majuro, in the Marshall Islands reflects this trend particularly well. The opposite La Niña effect, though present, is not so well illustrated. Using data from an earlier gauge maintained by the University of Hawaii, and the later SEAFRAME gauge installed in 1993 by the National Tidal Centre based in Adelaide, Australia, I've been able to reconstruct a history of sea level at Majuro Atoll from 1978 to 2011.
Here's a table of El Niño years. Those from 1969 to 2010 are clearly represented on the Majuro chart. The 1982-3 and 1997-8 El Niños were particularly strong events, and I've highlighted them in red
| |||||||||||||||||||||||||||||||
On the other (eastern) side of the Pacific, continuous long-term records are difficult to find, but that for Monterey, California illustrates the opposite effects quite well, although earlier El Niño years aren't quite so clearly defined.
The linear trend shows a value of 0.28 mm/month, which translates to 3.36 mm/year. However, the effect of the El Niños is to pull the trend line down progressively from right to left; it's always below the 13-month running mean (in red), more so on the left. A simple way to eliminate the negative effect of the El Niño "spikes" on the trend is to remove them from the data. However, this is not as easy as it sounds; there's a clear (approximately) annual cycle, illustrated by the sharp upward spikes. These "king tides" usually occur in late February or early March, occasionally as late as April, and their timing is due to the "lining up" of the tidal effects of both moon and sun. The all-time peak was in February 2006 (very clear on the graph), and despite dire predictions, hasn't yet been surpassed.
An Australian newspaper dispatched a team to Tuvalu in February 2011 to document what was expected to an all-time record "king tide". However, nature being as quirky as ever, organised things so that they'd already "missed the boat" (a metaphor becomes a bad pun!) as the highest tide had already occurred the previous month; indeed the February peak was lower than both January and March peaks. That and the fact that the January peak was no record, produced a "non-event" and no follow-up report was published.
However, I digress - removing the El Niño "spikes" must be done with care if an opposite upward bias is to be avoided. One way round this is to use annual data so the monthly cycle is not a problem, though it effectively removes more data. I'll be following up with a detailed analysis of late-20th century sea level rise at Tuvalu.
Data Sources
Marshall Islands (Majuro): Permanent Service for Mean Sea Level and South Pacific Sea Level and Climate Monitoring Project
Monterey: Permanent Service for Mean Sea Level
Tuvalu (Funafuti): Permanent Service for Mean Sea Level and South Pacific Sea Level and Climate Monitoring Project
Saturday, 24 December 2011
Seasonal Greetings
I've not posted for a while, but there are good reasons. I've been Excelling myself - I'll soon be posting more graphs than you can shake a hockeystick at. Australia will feature, thanks to the excellent records from the National Tidal Centre, whose SEAFRAME stations around Oz and the Pacific record climate data as well as sea-level, and show a distinct "lack of warming at the moment", to quote a now world-famous email. There are few Pacific islands which didn't show some warming from the early 1990s, but almost all show cooling since 1999. Posts on Oz and Pacific air and sea-surface (SST) temperatures soon.
I'll be updating and expanding the Pacific Sea Level post, and moving it to a permanent reference page. There'll be an Australian sea level post, also with a permanent page, and in the style of the interactive Pacific one.
In the meantime, whoever you are, and wherever you are, I surely can do no better than give you the Vulcan four-finger salute (note the number of fingers!), and in the immortal words of Mr Spock, "Live Long and Prosper".
I'll be updating and expanding the Pacific Sea Level post, and moving it to a permanent reference page. There'll be an Australian sea level post, also with a permanent page, and in the style of the interactive Pacific one.
In the meantime, whoever you are, and wherever you are, I surely can do no better than give you the Vulcan four-finger salute (note the number of fingers!), and in the immortal words of Mr Spock, "Live Long and Prosper".
Monday, 14 November 2011
South Pacific Sea Level to September 2011
Note: A permanent and (to be) regularly updated page has been created (see top of sidebar) located here. I've updated this page with data to December 2011.
The island sea level charts are drawn from monthly data from the South Pacific Sea Level and Climate Monitoring Project. I've included a chart for a second Fiji station, and also one at the end for a New Zealand station, Jackson Bay (South Island). Neither is part of the project, but data is provided on the website.
The high resolution SEAFRAME (Sea Level Fine Resolution Acoustic Measuring Equipment) monitoring stations comprise modern integrated housings which measure and record sea level, barometric pressure, water temperature and air temperature. Most of the stations were installed in 1992 and 1993, though a few were later. It's important to note that the effect of local land movement is eliminated from sea level data:
What should be evident from the plots is that any generalisation of the situation over this wide area is invalid. Apart from an almost universal downward spike during the 1997/98 ENSO event, the history and trends differ widely. It should also be clear that claims of "25 mm/year" or "no rise" since the early 1990s are also invalid.
Most of the charts are dominated by a downward "spike" in 1997/98. The level drop was due to unusually high barometric pressure during the 1997/98 ENSO ("El Niño/La Niña-Southern Oscillation") event. The correlation is well illustrated for the Marshall Islands (Majuro Atoll), so I've placed this first. Kiribati and Tuvalu have been given much attention in the news media and on the 'net recently, so they're listed next.
Readers are welcome to reproduce any of the plots - all I ask is that attribution be given, preferably with a link to this post. I haven't used thumbnails - right-click on the image and select "save image as" or whatever your browser prompts.
Level data has been converted from metres to millimetres to overcome loss of precision in Excel's trend data. Gaps in the plots indicate gaps in the original data. Note that the trend slope is monthly - multiply by 12 to get the annual value (e.g. y = 0.2269x gives 2.7228 mm/year).
Select a location from the map to view a graph of the monthly sea level statistics for that location. Click on the bottom of the blue area for the NZ station, Click on your browser's back button to return to the map.
Note the 1997/98 ENSO "spike" and the correspondence with the abnormally high atmospheric pressure from late 1997 to late 1998 shown in the barometric pressure plot below:
The trend line is pulled down by the ENSO dip from the end of 1997 to end 1998. To give an better view of the trend from 1992 to present, I replotted the chart with that data excluded:
The resulting trend is effectively zero.
A downward trend is evident from end 2001 to present:
As with Kiribati, the deep ENSO dip in 1997/98 pulls the trend line down on the left; it's below the 1994/1997 average. A zero trend is evident from 1999 to present:
Here's a clearer view of the 1999-2011 trend of 3.4 mm/year, slightly above the global average:
Again the trend is pulled down on the left; the average level 1999 to present is around 750 mm, and the trend 2.1 mm/year.
The big 1997/98 downward spike evident in most of the other plots is absent; instead there's a relatively steady upward trend.
Island: Viti Levu Location: Suva
Although there's a steep trend from 1993, current levels are not dissimilar to those between 2000 and 2003.
Levels seem to have stabilised from 2006.
The familiar ENSO dip pulls the trend down at the LHS, but there is a sharp upward "spike" from 2010.
![]()
Overall trend is effectively flat - levels at present similar to those in 1993. However, the trend from 2002 is downward.
An overall upward trend, though little change from 2007 to present.
There seems to be little overall change from mid-1998 (after the ENSO dip) to present. A plot from 1999 confirms that:
The island sea level charts are drawn from monthly data from the South Pacific Sea Level and Climate Monitoring Project. I've included a chart for a second Fiji station, and also one at the end for a New Zealand station, Jackson Bay (South Island). Neither is part of the project, but data is provided on the website.
The high resolution SEAFRAME (Sea Level Fine Resolution Acoustic Measuring Equipment) monitoring stations comprise modern integrated housings which measure and record sea level, barometric pressure, water temperature and air temperature. Most of the stations were installed in 1992 and 1993, though a few were later. It's important to note that the effect of local land movement is eliminated from sea level data:
The Continuous Global Positioning System (CGPS) network monitors vertical movement in the earth's crust, such as subsidence or tectonic shifts, at the SEAFRAME tide gauges and adjacent land. Sea level data can then be adjusted to compensate for the earth's movement to within a millimeter, enabling the absolute sea level to be determined.I have voiced criticism of Australia's Bureau of Meteorology on various topics in the past, but as far as the presentation of sea level data is concerned, I rate their National Tidal Centre as the best. The page I linked to above has a table of the 12 stations in the project (and the two others I mentioned) which links to PDF plots and data tables for sea level, barometric pressure, water temperature and air temperature. The data tables in turn link to online graphical plots and text files for easy import to spreadsheets. A map links directly to the data tables. I liked that Idea so much I've pinched it for use here.
What should be evident from the plots is that any generalisation of the situation over this wide area is invalid. Apart from an almost universal downward spike during the 1997/98 ENSO event, the history and trends differ widely. It should also be clear that claims of "25 mm/year" or "no rise" since the early 1990s are also invalid.
Most of the charts are dominated by a downward "spike" in 1997/98. The level drop was due to unusually high barometric pressure during the 1997/98 ENSO ("El Niño/La Niña-Southern Oscillation") event. The correlation is well illustrated for the Marshall Islands (Majuro Atoll), so I've placed this first. Kiribati and Tuvalu have been given much attention in the news media and on the 'net recently, so they're listed next.
Readers are welcome to reproduce any of the plots - all I ask is that attribution be given, preferably with a link to this post. I haven't used thumbnails - right-click on the image and select "save image as" or whatever your browser prompts.
Level data has been converted from metres to millimetres to overcome loss of precision in Excel's trend data. Gaps in the plots indicate gaps in the original data. Note that the trend slope is monthly - multiply by 12 to get the annual value (e.g. y = 0.2269x gives 2.7228 mm/year).
Select a location from the map to view a graph of the monthly sea level statistics for that location. Click on the bottom of the blue area for the NZ station, Click on your browser's back button to return to the map.
![Click on a red dot to jump to the relevant sea level graph](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnkfe-KIX-AhM5XPeFklgJ12RcZgwCjtT6Me6wOzK1RJ1plzEZbHLLfyJgrHhqqqPtOHs73BiHGtYvlMtA715A1p_PJ8n0jjg1gVzbqi7Wrd_eoqvOWdKav943FBmTnuYYHcM28zgWsOg/s1600/pacific.gif" "Click on a red dot to jump to the relevant sea level graph") |
| Source: Bureau of Meteorology |
Marshall Islands
Island: Majura Location: UligaNote the 1997/98 ENSO "spike" and the correspondence with the abnormally high atmospheric pressure from late 1997 to late 1998 shown in the barometric pressure plot below:
Kiribati
Island: Tarawa Location: BetioThe trend line is pulled down by the ENSO dip from the end of 1997 to end 1998. To give an better view of the trend from 1992 to present, I replotted the chart with that data excluded:
A downward trend is evident from end 2001 to present:
Tuvalu
Atoll:Funafuti Island: FongafaleAs with Kiribati, the deep ENSO dip in 1997/98 pulls the trend line down on the left; it's below the 1994/1997 average. A zero trend is evident from 1999 to present:
Papua New Guinea
Island: Manus Location: LombrumHere's a clearer view of the 1999-2011 trend of 3.4 mm/year, slightly above the global average:
Solomon Islands
Island: Guadalcanal Location: HoniaraVanuatu
Island: Efate Location: Port VilaThe big 1997/98 downward spike evident in most of the other plots is absent; instead there's a relatively steady upward trend.
Fiji
Island: Viti Levu Location: LautokaIsland: Viti Levu Location: Suva
Tonga
Island: Tongatapu Location: Nuku'alofaAlthough there's a steep trend from 1993, current levels are not dissimilar to those between 2000 and 2003.
Cook Islands
Island: Rarotonga Location: AvatiuLevels seem to have stabilised from 2006.
Samoa
Island: Upolu Location: ApiaThe familiar ENSO dip pulls the trend down at the LHS, but there is a sharp upward "spike" from 2010.
Nauru
Island: Nauru Location: Aiwo
Federated States of Micronesia
Island: Pohnpei Location: DekehtikAn overall upward trend, though little change from 2007 to present.
New Zealand
Island: South Island Location: Jackson BayThere seems to be little overall change from mid-1998 (after the ENSO dip) to present. A plot from 1999 confirms that:
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