winterymix Posted July 7, 2012 Share Posted July 7, 2012 Inversely-correlated trends are powerful when illustrating trends over a century. Link to comment Share on other sites More sharing options...
donsutherland1 Posted July 7, 2012 Author Share Posted July 7, 2012 Good post. Really surprised to see no one reply to this. There's still a lot to be learned about blocking. There's also a lot of variability involved. Hence, even if the continuing dramatic warming of the Arctic increases prospects of blocking, that does not assure that every winter will feature a lot of blocking. In short, even as there has been some promising work done e.g., regarding the connection between autumnal snow cover changes in Siberia and blocking, it remains difficult to have much confidence in whether or not a given winter will be blocky until one gets close to the start of winter. Even then, there is high risk of error. Link to comment Share on other sites More sharing options...
ORH_wxman Posted July 7, 2012 Share Posted July 7, 2012 There's still a lot to be learned about blocking. There's also a lot of variability involved. Hence, even if the continuing dramatic warming of the Arctic increases prospects of blocking, that does not assure that every winter will feature a lot of blocking. In short, even as there has been some promising work done e.g., regarding the connection between autumnal snow cover changes in Siberia and blocking, it remains difficult to have much confidence in whether or not a given winter will be blocky until one gets close to the start of winter. Even then, there is high risk of error. The snow cover in Siberia seems to have the highest correlation to me when looking over past winters. Of course its far from perfect, but it seems to be a better proxy than sea ice or some other variable. We have snow cover records back to 1967 on Rutgers...we fell from a peak (in autumn snow cover in Siberia) at the beginning of their records to a minimum in the 1980s/early 1990s and have risen since then...which is generally what the NAO has done as well, but inversely correlated. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted July 7, 2012 Share Posted July 7, 2012 In no way do I mean to suggest that JB has a bad motive. People are, in general, rational and purposeful. Hence, people typically have reasons for their choices and decisions. JB appears to have made a decision to shift, at least in part, the focus of his discussions away from meteorology and toward climate. Don, I was wondering what your thoughts are on Joe D'Aleo, JBs business partner? When Weatherbull was free I used to read some of his articles and they were quite interesting. I ask because, like JB, he is a AGW skeptic, yet he seems to be better liked and respected than JB amongst board members. Link to comment Share on other sites More sharing options...
donsutherland1 Posted July 7, 2012 Author Share Posted July 7, 2012 Don, I was wondering what your thoughts are on Joe D'Aleo, JBs business partner? When Weatherbull was free I used to read some of his articles and they were quite interesting. I ask because, like JB, he is a AGW skeptic, yet he seems to be better liked and respected than JB amongst board members. Probably a combination of factors ranging from personality to perhaps some being frustrated with his most recent winter forecast. Link to comment Share on other sites More sharing options...
Msalgado Posted July 7, 2012 Share Posted July 7, 2012 The snow cover in Siberia seems to have the highest correlation to me when looking over past winters. Of course its far from perfect, but it seems to be a better proxy than sea ice or some other variable. We have snow cover records back to 1967 on Rutgers...we fell from a peak (in autumn snow cover in Siberia) at the beginning of their records to a minimum in the 1980s/early 1990s and have risen since then...which is generally what the NAO has done as well, but inversely correlated. The studies alluded to weren't about using sea ice as a proxy, however. It was a study as to how the actual dynamics of more open sea in the arctic change atmospheric circulations. It should be noted that as AGW grows, the amount of usable and meaningful proxies may fall. Statistical modeling may becoming increasingly less useful because of this. Link to comment Share on other sites More sharing options...
ORH_wxman Posted July 7, 2012 Share Posted July 7, 2012 The studies alluded to weren't about using sea ice as a proxy, however. It was a study as to how the actual dynamics of more open sea in the arctic change atmospheric circulations. It should be noted that as AGW grows, the amount of usable and meaningful proxies may fall. Statistical modeling may becoming increasingly less useful because of this. Well they said that low sea ice may have helped blocking to occur. I suppose its possible, but the cycle of autumn snow cover in Siberia seems to be more robust on the decadal scale in inversely correlating with the NAO. I do agree that proxies become less usable as the weather becomes more erratic. Link to comment Share on other sites More sharing options...
Msalgado Posted July 7, 2012 Share Posted July 7, 2012 It may be an interesting exercise to see if analogues are actually less likely in the past 15-20 years to give an accurate indicator than they were in timeframes before. Link to comment Share on other sites More sharing options...
ORH_wxman Posted July 7, 2012 Share Posted July 7, 2012 It may be an interesting exercise to see if analogues are actually less likely in the past 15-20 years to give an accurate indicator than they were in timeframes before. They are very useful...just often you have to adjust for the climate we are in. Both backround warming and the decadal oscillations. Analogues only from the recent 1980s/1990s would have proven less useful than the earlier analogues from the 1950s/1960s/1970s in winter long range forecasts in the past decade since those earlier analogues had a lot of snowier patterns and we have generally had the snowier patterns again. But obviously we aren't quite as cold as those decades....however it has been a closer match than the 1980s/1990s. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted July 7, 2012 Share Posted July 7, 2012 What intrigues me is that, while we are experiencing hotter summers in the means up here, in the absolutes we have yet to touch months like July 1911 and July 1936. Take a look at July 1911 in Toronto. http://www.climate.weatheroffice.gc.ca/climateData/dailydata_e.html?timeframe=2&Prov=ONT&StationID=5051&mlyRange=1840-01-01|2006-12-01&cmdB1=Go&Year=1911&Month=7&Day=6 Also July 1936: http://www.climate.weatheroffice.gc.ca/climateData/dailydata_e.html?timeframe=2&Prov=ONT&StationID=5051&mlyRange=1840-01-01|2006-12-01&cmdB1=Go&Month=7&Year=1936&Day=6 Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted July 8, 2012 Share Posted July 8, 2012 I believe you're correct. The higher latitudes have, in general, been warming faster. Although a number of the summers in the 1930s, especially 1934 and 1936 ranked very high in terms of warmth in the CONUS, a number of recent summers have also been exceptionally warm. 2010 was the 4th warmest summer and 2011 was the 2nd warmest in the U.S. Due to a server issue, the NCDC page from which one can get the ranking of U.S. summers is down, so I can't provide a full list of the 10 or 20 warmest summers. Summer 1966 does not rank in the top 10. Despite scorching heat in late June and early July, that summer had a very cool August. Unfortunately, as he has gotten more involved in the climate change debate, JB has seemingly developed a tendency to sometimes downplay current warmth. I use "seemingly" as I haven't regularly followed his tweets, but have irregularly looked (mostly to see what he has been saying during weather extremes). I have regularly followed him since the outbreak of the current episode of heat in late June. For example, back in March JB downplayed the historic "Summer in March" heat (possibly the most anomalous weather event in the instrument record in North America, with multiple areas seeing high temperatures 4 and even 5 standard deviations above normal; some cities wound up beating all-time April highs, too). In one tweet, JB remarked: Fact is for the nation as a whole 1910 blows this away. Fact is in spite of our warmth, the planet is cool.. Fact is this is not AGW When the data was tallied up, March 2012 was the warmest March on record in the U.S. In fact, it shattered the 1910 record by 0.5°F. With all due respect, beating a national record by a full 0.5° is 'blowing away' the old record (1910). In addition, March saw 7,755 daily record maximum temperature and 586 monthly record maximum temperature records tied or broken. In addition, March saw 7,517 daily highest minimum temperature and 511 monthly highest minimum temperature records tied or broken. Canada, too, experienced the historic heat with many daily and monthly records being shattered, some on multiple days. Also, the March 2012 global land and sea anomaly was a warm one, not a cold one. In any case, it appears that JB has dramatically departed from past practice when he used to discuss the weather and leverage his exceptional recognition of synoptic patterns in doing so. Perhaps he believes that an increased focus on the contrarian climate position will allow him to differentiate himself from his peers? Perhaps he wants to assert that natural cycles remain important? If so, there are better ways to go about doing that. I'm not sure what the calculation is, because meteorology is not the same thing as climate science. I don't believe WeatherBell is competing in the climate science field or seeking to do so, but then again one has to be cautious here. We don't know who WeatherBell's clients are nor their needs. What appears to be more clear is that he has apparently shifted his focus, at least in part, from an area in which he enjoyed a comparative advantage (understanding of synoptic patterns and their evolution/teleconnections) into one in which he is at a decided disadvantage. The points he's made regarding climate often are at odds with the data, statistical relationships, and the literature in the field. Here is a link to JBs video summary for this weekend. Note that it is from the free site, not the pay site. http://www.weatherbell.com/saturday-summary-july-7-2012 Link to comment Share on other sites More sharing options...
donsutherland1 Posted July 8, 2012 Author Share Posted July 8, 2012 In a tweet today, JB claimed that Washington, DC averaged 27 days per year with temperatures of 95° or above during the 1930s. The source of that incorrect claim was actually another blogger. That blogger stated in his headline that "DC was hotter during the 1930s." However, rather than providing data from Washington, DC, the blogger posted statistics from Lincoln, VA, which is in the Blue Ridge Mountains in western Virginia. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted July 8, 2012 Share Posted July 8, 2012 In a tweet today, JB claimed that Washington, DC averaged 27 days per year with temperatures of 95° or above during the 1930s. The source of that incorrect claim was actually another blogger. That blogger stated in his headline that "DC was hotter during the 1930s." However, rather than providing data from Washington, DC, the blogger posted statistics from Lincoln, VA, which is in the Blue Ridge Mountains in western Virginia. That's absurd, but not surprising. Link to comment Share on other sites More sharing options...
uncle W Posted July 8, 2012 Share Posted July 8, 2012 many years ago some scientists predicted temperatures would rise especially night time lows...Average highs for NYC has gone up slightly while night time lows rose faster...Since March 2010 many record warm minimums were set...These are the Summer decade numbers for NYC...Not official numbers...I did my own research... Three month period from 6/1 - 8/31 decade...ave temp/precip...90+days100+ 1870's.....73.2.....13.75".....101.....0..... 1880's.....72.4.....11.88".......81.....1..... 1890's.....73.3.....11.18".....138.....1..... 1900's.....73.3.....12.87".....101.....2..... 1910's.....72.7.....11.58".....115.....3..... 1920's.....72.6.....12.98".....128.....2..... 1930's.....74.6.....12.40".....189.....8..... 1940's.....74.2.....11.86".....202.....8..... 1950's.....74.4.......9.86".....175...12..... 1960's.....74.2.....10.54".....181.....4..... 1970's.....74.6.....12.61".....183.....3..... 1980's.....75.0.....13.03".....195.....2..... 1990's.....75.0.....11.90".....197.....8..... 2000's.....74.3.....15.66".....123.....1..... 2010's.....76.9.....17.09".......68.....4.....as of 7/8/2012 for 90/100+ days... 1870- 2009 ave 73.8.....12.29".....149.....4..... 1980- 2009 ave 74.8.....13.53".....172.....4. ................................................................. the 1930's show a sharp rise in 90+ days and the trend continued thru the 1940's...The 50's 60's and 70's averaged around 18 per year...The 1980's and 1990's had an increase...The 2000's had a sharp drop in 90+ days with the lowest number since the 1910's...the 2010's are on a pace to have the most 90 degrees days...the 1940's averaged just over 20 per year...So far the 2010's as of today is averaging 23 but that number will go up significantly by Summers end...Precipitation was on the rise until this year's more normal numbers...The average temperature was down in the 2000's but is on the rise since 2010...The 2010's is a small sample and by 2019 the averages might be close to normal with a few cool years...the 1930's had a two degree rise on average over the 1920's...the average remained pretty steady until the last three years... Link to comment Share on other sites More sharing options...
Jonger Posted July 9, 2012 Share Posted July 9, 2012 many years ago some scientists predicted temperatures would rise especially night time lows...Average highs for NYC has gone up slightly while night time lows rose faster...Since March 2010 many record warm minimums were set...These are the Summer decade numbers for NYC...Not official numbers...I did my own research... Three month period from 6/1 - 8/31 decade...ave temp/precip...90+days100+ 1870's.....73.2.....13.75".....101.....0..... 1880's.....72.4.....11.88".......81.....1..... 1890's.....73.3.....11.18".....138.....1..... 1900's.....73.3.....12.87".....101.....2..... 1910's.....72.7.....11.58".....115.....3..... 1920's.....72.6.....12.98".....128.....2..... 1930's.....74.6.....12.40".....189.....8..... 1940's.....74.2.....11.86".....202.....8..... 1950's.....74.4.......9.86".....175...12..... 1960's.....74.2.....10.54".....181.....4..... 1970's.....74.6.....12.61".....183.....3..... 1980's.....75.0.....13.03".....195.....2..... 1990's.....75.0.....11.90".....197.....8..... 2000's.....74.3.....15.66".....123.....1..... 2010's.....76.9.....17.09".......68.....4.....as of 7/8/2012 for 90/100+ days... 1870- 2009 ave 73.8.....12.29".....149.....4..... 1980- 2009 ave 74.8.....13.53".....172.....4. ................................................................. the 1930's show a sharp rise in 90+ days and the trend continued thru the 1940's...The 50's 60's and 70's averaged around 18 per year...The 1980's and 1990's had an increase...The 2000's had a sharp drop in 90+ days with the lowest number since the 1910's...the 2010's are on a pace to have the most 90 degrees days...the 1940's averaged just over 20 per year...So far the 2010's as of today is averaging 23 but that number will go up significantly by Summers end...Precipitation was on the rise until this year's more normal numbers...The average temperature was down in the 2000's but is on the rise since 2010...The 2010's is a small sample and by 2019 the averages might be close to normal with a few cool years...the 1930's had a two degree rise on average over the 1920's...the average remained pretty steady until the last three years... Despite having the worlds biggest UHI, NYC hasn't really changed a whole lot, WAY too early to determine 2010's. Link to comment Share on other sites More sharing options...
winterymix Posted July 9, 2012 Share Posted July 9, 2012 Despite having the worlds biggest UHI, NYC hasn't really changed a whole lot, WAY too early to determine 2010's. 73.2 to 76.9 is a huge change. Whenever cooling trends initiate, those cool temperature departures are easily overcome and moderated in the direction of a warming climate trend. On the other hand, heat waves and warm trends seem to have robust persistence. If I were a buyer for a department store in the Northeast US, I wouldn't want to overbuy heavy winter clothing else, the unsold inventory be sold off end of season at a loss. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted July 9, 2012 Share Posted July 9, 2012 In a tweet today, JB claimed that Washington, DC averaged 27 days per year with temperatures of 95° or above during the 1930s. The source of that incorrect claim was actually another blogger. That blogger stated in his headline that "DC was hotter during the 1930s." However, rather than providing data from Washington, DC, the blogger posted statistics from Lincoln, VA, which is in the Blue Ridge Mountains in western Virginia. JB is losing a lot of credibility. I'm really glad that I no longer pay to read his thoughts. Link to comment Share on other sites More sharing options...
donsutherland1 Posted July 9, 2012 Author Share Posted July 9, 2012 In a blog entry, Anthony Watts wrote of the recent extreme outbreak of heat: This is a combination of two posts elsewhere that illustrate just how much hype and how little substance the MSM and blogs like Grist, Climate Progress. and Capital Weather Gang have been pushing trying to make a run of the mill summer heat wave seem like an event of unprecedented global warming proportions. It isn’t, and not even close compared to weather records history of the past. If one examines the facts, the recent outbreak of heat was not a "run of the mill summer heat wave." At the height of the heat wave, some cities in a region encompassing the Great Lakes. Ohio Valley, Tennessee Valley, Southeast, and Mid-Atlantic regions saw high temperatures crest 3-4 standard deviations above normal. With Mr. Watts taking a shot at The Washington Post's Capital Weather Gang, a closer look at the heat in Washington, D.C. is in order. Some key statistics: June 28: High: 96° (1.464 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 7.160% June 29: High: 104° (2.801 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 0.255% June 30: High: 97° (1.631 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 5.145% July 1: High: 99° (1.965 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 2.471% July 2: High: 95° (1.297 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 9.732% July 3: High: 98° (1.798 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 3.609% July 4: High: 99° (1.965 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 2.471% July 5: High: 100° (2.133 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 1.646% July 6: High: 100° (2.133 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 1.646% July 7: High: 105° (2.968 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 0.150% July 8: High: 102° (2.467 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 0.681% June 28-July 8, 2012 Period: Mean High: 99.5° (2.057 Sigma above the June 28-July 8 Average High for the 1981-2010 base period); Statistical Probability: 1.984% Consecutive 100° Highs: 4 (Statistical Probability of such an Occurrence during the June 28-July 8 period: 0.00000734%) IMO, any person possessing reasonable knowledge of meteorology, climatology, and/or statistics could only reject the hypothesis that the recent heat wave was not an extreme event. To not do so with such knowledge could only represent the propagation of disinformation. That no examples of past heat waves that far surpassed the current one were provided speaks speaks for itself. FWIW, the only somewhat more extreme heat event in Washington, D.C. was the July 18-29, 1930 heat wave (Average high: 98.7°, 4 consecutive 100° readings, including a 106° reading, and 6 100° readings). Link to comment Share on other sites More sharing options...
hazwoper Posted July 9, 2012 Share Posted July 9, 2012 The frequency of record highs is not increasing very much (if at all) against earlier decades, it's more of a case of very infrequent record lows. This would be expected in a climate so moderated by ocean temperatures. Roger, sorry, I am reading this a bit late, but was curious as to what you, thought about the much larger decrease in record lows vs. record highs? Wouldn't this point more towards the expansion of our urbanized areas (surburban sprawl) and larger heat islands thus contributing to larger areas holding on to more heat then previous decades. Not trying to bring up the old "urban heat island is the cause of these temps" argument, cause I know that wouldn't mean squat from the satellite data standpoint and global temperatures as a whole, but when looking at record lows at specific locations where they have been recording temps for hundreds of years, seems some of the reason we don't see the larger number of record lows is at least partially due to urbanization and retaining heat for longer periods. EDIT - and if this was already brought up on an earlier page of this thread I appolgize. Link to comment Share on other sites More sharing options...
hazwoper Posted July 9, 2012 Share Posted July 9, 2012 the UHI myth has been debunked dozens of times in this forum. wxtrix - did you not read my second paragraph? I was simply trying to get Rogers (or anyone lese for that matter) thoughts on the decreasing number of record lows that have been recorded since 1772, not that UHI is the reason for overall global temp increases. Are you telling me that Philadelphia (for instance) has not seen a decreasing number of record low temps since the 1800's that is at leastb partially due to development??? You do realize that the majority of the city which is now completely covered by asphalt, buildings, etc. was actaully farmland/forrests in the early 1800's correct? You also realize that UHI's hold the temps of the day whereas the areas jusr outside the urban areas lose heat much more rapidly? For instance, I drove from my home in Bucks County last Friday night. Left at 9:00PM and the temp was 84. Once I got to center city at around 9:30P the temp was 96. The difference during the day that day was certainly not 12 degrees from my home to Center City. Link to comment Share on other sites More sharing options...
hazwoper Posted July 9, 2012 Share Posted July 9, 2012 the answer is no. still. http://www.skeptical...?a=links&arg=32 disagree. Again, this is not an argument on my part to state that UHI is a cause for Global Warming, or even a major contributor for that matter, just that the decreased numbers of record lows COULD be an effect of urban sprawl due to retaining heat during the time period when those areas should be losing heat. The effect would be far less on the actual high temps. But, I'll just wait to hear from others rather than continue to reply to (its been debunked and "the answer is still no") Link to comment Share on other sites More sharing options...
donsutherland1 Posted July 9, 2012 Author Share Posted July 9, 2012 ...seems some of the reason we don't see the larger number of record lows is at least partially due to urbanization and retaining heat for longer periods. On a very localized basis, perhaps, especially where the radiational cooling impact has been blunted. In a larger context, probably not. From an abstract to a paper on UHI and climate change: Comparisons of windy weather with calm‐weather air temperature trends for a worldwide set of observing sites suggest that global near‐surface temperature trends have not been greatly affected by urban warming trends... http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WCC21.html Link to comment Share on other sites More sharing options...
hazwoper Posted July 9, 2012 Share Posted July 9, 2012 On a very localized basis, perhaps, especially where the radiational cooling impact has been blunted. In a larger context, probably not. From an abstract to a paper on UHI and climate change: Comparisons of windy weather with calm‐weather air temperature trends for a worldwide set of observing sites suggest that global near‐surface temperature trends have not been greatly affected by urban warming trends... http://wires.wiley.c...isId-WCC21.html Thanks Don. That is all I was trying to get at. From a very localized standpoint, the lower numbers of record lows at any particular station could be effected by urban sprawl, but I certainly do NOT believe that this accounts for ALL of the reductions. Link to comment Share on other sites More sharing options...
SVT450R Posted July 9, 2012 Share Posted July 9, 2012 wxtrix - did you not read my second paragraph? I was simply trying to get Rogers (or anyone lese for that matter) thoughts on the decreasing number of record lows that have been recorded since 1772, not that UHI is the reason for overall global temp increases. Are you telling me that Philadelphia (for instance) has not seen a decreasing number of record low temps since the 1800's that is at leastb partially due to development??? You do realize that the majority of the city which is now completely covered by asphalt, buildings, etc. was actaully farmland/forrests in the early 1800's correct? You also realize that UHI's hold the temps of the day whereas the areas jusr outside the urban areas lose heat much more rapidly? For instance, I drove from my home in Bucks County last Friday night. Left at 9:00PM and the temp was 84. Once I got to center city at around 9:30P the temp was 96. The difference during the day that day was certainly not 12 degrees from my home to Center City. I totally agree with what your saying. Link to comment Share on other sites More sharing options...
SVT450R Posted July 9, 2012 Share Posted July 9, 2012 the UHI myth has been debunked dozens of times in this forum. Yup no UHI here at Tucson University of Arizona. Link to comment Share on other sites More sharing options...
PhillipS Posted July 9, 2012 Share Posted July 9, 2012 disagree. Again, this is not an argument on my part to state that UHI is a cause for Global Warming, or even a major contributor for that matter, just that the decreased numbers of record lows COULD be an effect of urban sprawl due to retaining heat during the time period when those areas should be losing heat. The effect would be far less on the actual high temps. But, I'll just wait to hear from others rather than continue to reply to (its been debunked and "the answer is still no") Trixie is correct, the UHI meme has been debunked repeatedly. One of the four BEST project reports deals specifically with UHI trends and they found that urban stations are measuring the same trend as rural stations. But let's do a quick reality check - if the scarcity of record low temps was caused by UHI then why aren't rural stations and satellietes seeing the same frequency of record lows? Here's the link to the draft UHI paper from the BEST project. The from the conclusions section: We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.19 ± 0.19 °C/100yr. This is not statistically consistent with prior estimates, but it does verify that the effect is very small, and almost insignificant on the scale of the observed warming (1.9 ± 0.1 °C/100yr since 1950 in the land average from figure 5A). Only during the very recent period does the difference between the very-rural station average and the average from the complete data set become statistically significant. This would suggest the existence of a residual urbanization bias in the Berkeley Earth averaging technique, albeit one whose sign is contrary to the traditional expectation. We hesitate to offer any explanation for this specific difference given the relatively short interval of deviation until a more detailed investigation has been made. The natural explanations might require some recent form of “urban cooling” and/or “rural warming”. Alternatively, the effect might be related to some subtle difference in the spatial coverage of rural and nonrural sites at recent times; however, preliminary analysis tends to make this latter suggestion appear unlikely. We note that our averaging procedure uses only land temperature records. Inclusion of ocean temperatures will further decrease the influence of urban heating since it is not an ocean phenomenon. Including ocean temperatures in the Berkeley Earth reconstruction is an area of future work. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted July 9, 2012 Share Posted July 9, 2012 Trixie is correct, the UHI meme has been debunked repeatedly. One of the four BEST project reports deals specifically with UHI trends and they found that urban stations are measuring the same trend as rural stations. But let's do a quick reality check - if the scarcity of record low temps was caused by UHI then why aren't rural stations and satellietes seeing the same frequency of record lows? Here's the link to the draft UHI paper from the BEST project. The from the conclusions section: We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.19 ± 0.19 °C/100yr. This is not statistically consistent with prior estimates, but it does verify that the effect is very small, and almost insignificant on the scale of the observed warming (1.9 ± 0.1 °C/100yr since 1950 in the land average from figure 5A). Only during the very recent period does the difference between the very-rural station average and the average from the complete data set become statistically significant. This would suggest the existence of a residual urbanization bias in the Berkeley Earth averaging technique, albeit one whose sign is contrary to the traditional expectation. We hesitate to offer any explanation for this specific difference given the relatively short interval of deviation until a more detailed investigation has been made. The natural explanations might require some recent form of “urban cooling” and/or “rural warming”. Alternatively, the effect might be related to some subtle difference in the spatial coverage of rural and nonrural sites at recent times; however, preliminary analysis tends to make this latter suggestion appear unlikely. We note that our averaging procedure uses only land temperature records. Inclusion of ocean temperatures will further decrease the influence of urban heating since it is not an ocean phenomenon. Including ocean temperatures in the Berkeley Earth reconstruction is an area of future work. Thanks for the read. I guess some people think the BEST project is a scam like GISS is a scam. What else is there to be said? Link to comment Share on other sites More sharing options...
hazwoper Posted July 9, 2012 Share Posted July 9, 2012 Trixie is correct, the UHI meme has been debunked repeatedly. One of the four BEST project reports deals specifically with UHI trends and they found that urban stations are measuring the same trend as rural stations. But let's do a quick reality check - if the scarcity of record low temps was caused by UHI then why aren't rural stations and satellietes seeing the same frequency of record lows? Here's the link to the draft UHI paper from the BEST project. The from the conclusions section: We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.19 ± 0.19 °C/100yr. This is not statistically consistent with prior estimates, but it does verify that the effect is very small, and almost insignificant on the scale of the observed warming (1.9 ± 0.1 °C/100yr since 1950 in the land average from figure 5A). Only during the very recent period does the difference between the very-rural station average and the average from the complete data set become statistically significant. This would suggest the existence of a residual urbanization bias in the Berkeley Earth averaging technique, albeit one whose sign is contrary to the traditional expectation. We hesitate to offer any explanation for this specific difference given the relatively short interval of deviation until a more detailed investigation has been made. The natural explanations might require some recent form of “urban cooling” and/or “rural warming”. Alternatively, the effect might be related to some subtle difference in the spatial coverage of rural and nonrural sites at recent times; however, preliminary analysis tends to make this latter suggestion appear unlikely. We note that our averaging procedure uses only land temperature records. Inclusion of ocean temperatures will further decrease the influence of urban heating since it is not an ocean phenomenon. Including ocean temperatures in the Berkeley Earth reconstruction is an area of future work. That is fine, but I was just stating that the number of "record lows" may be distorted due to UHIs, not global warming as a whole. Also, that paper used number of lights at night from satelites to determine urban, pre-urban and rural, but does not go into any detail on how that analysis was made. Link to comment Share on other sites More sharing options...
Msalgado Posted July 9, 2012 Share Posted July 9, 2012 The majority of stations aren't in UHI so why would UHI show such an affect? Link to comment Share on other sites More sharing options...
NEXtreme Posted July 10, 2012 Share Posted July 10, 2012 I believe Dr Ryan Mau has been doing a check list on the silly media headlines on the "greatest heat wave to hit mankind" Kinda funny. This should no doubt free the north pole of ice by October. If I'm to believe that it is human generated then what is the explanation for the incredible heat waves of the medievel times,1920's ,1930's and with less humans around, not to mention a vastly less industrialized world? Why was it so hot? I'm really struggling with that. If some records have stood since then, and many still do, 80-100 yrs ago, doesn't that cause you to wonder: geeze it musta been hot then too. This is not new to our climate! So, extreme heat broke how many records? Out of how many? 3,000, 300k, or 3 million? How many records weren't broken -- is a good question. And check this out, not government funded: http://www.uni-mainz.de/eng/15491.php Very interesting to say the least. Link to comment Share on other sites More sharing options...
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