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anybody
2009-Mar-31, 09:27 AM
We have heard that global Warming is a big threat, but now I read.

Solar inactivity leading to new ice age. (http://www.nationalpost.com/opinion/columnists/story.html?id=332289)
We are actually heading towards a new Ice Age, claim scientists. (http://www.dailymail.co.uk/sciencetech/article-1085359/Global-warning-We-actually-heading-new-Ice-Age-claim-scientists.html)
New Ice Age averted by global Warming. (http://news.nationalgeographic.com/news/2008/11/081112-ice-age-global-warming.html)

Achak
2009-Apr-01, 11:08 AM
2 Winters ago in the Boreal Hemisphere we had more snow than usual.

This Winter we broke cold records almost everywhere, Russia, Alaska, Yukon, Prairies, Europe, Marocco, Northern India, China.

If all this is global warming then keep it up and turn the thermostat higher.

Defenitively Cooling down in Boreal Hemisphere as it happens each time when there is no sunspots.

Wonder how the fishes will be intwo months, as for dogs and wolves many got killed by cold this winter.

Achak

anybody
2009-Apr-01, 11:36 AM
We had the coldest winter in more than 10 years, there was lottsa below zero.

lomiller1
2009-Apr-01, 08:15 PM
Despite the strong La Nina in late 2007 and early 2008, last year was the 7th – 10th warmest on record and was warmer then every single year prior to 1998.

http://data.giss.nasa.gov/gistemp/2008/



Calendar year 2008 was the coolest year since 2000, according to the Goddard Institute for Space Studies analysis [see ref. 1] of surface air temperature measurements. In our analysis, 2008 is the ninth warmest year in the period of instrumental measurements, which extends back to 1880 (left panel of Fig. 1). The ten warmest years all occur within the 12-year period 1997-2008. The two-standard-deviation (95% confidence) uncertainty in comparing recent years is estimated as 0.05įC [ref. 2], so we can only conclude with confidence that 2008 was somewhere within the range from 7th to 10th warmest year in the record.


The problem with looking at a 10 year period is that the natural year to year variation is large enough to skew the trend. If you only look at the last 10 the error bars are large enough to encompass either a) warming continued unabated or b) warming stopped so you really need to look at a longer period to make any conclusions. When you look at a long enough period for the results to be statistically significant, you see warming of ~0.2 degrees per decade.

novaderrik
2009-Apr-01, 08:21 PM
it could be the climate just doing what it always does. warm some years, cool some years, trends up over some periods of time, trends down in some periods of time.
of course, if it starts to trend downward now, the stated reason will be the economic downturn and humans doing less civilised human stuff and putting less evil stuff in the air.

nauthiz
2009-Apr-01, 09:09 PM
Look at the timeframe given in both of the second two articles - 10,000 to 100,000 years from now.

korjik
2009-Apr-02, 03:30 PM
Despite the strong La Nina in late 2007 and early 2008, last year was the 7th Ė 10th warmest on record and was warmer then every single year prior to 1998.

http://data.giss.nasa.gov/gistemp/2008/



The problem with looking at a 10 year period is that the natural year to year variation is large enough to skew the trend. If you only look at the last 10 the error bars are large enough to encompass either a) warming continued unabated or b) warming stopped so you really need to look at a longer period to make any conclusions. When you look at a long enough period for the results to be statistically significant, you see warming of ~0.2 degrees per decade.

Which goes to show the problem with looking at just global temp data. North American weather patterns have been way out of whack for the last two years. Either the global averaging is skewed, or the temp data is counterproductive. Saying that the last year was one of the warmest on record when there was a blizzard in Texas this week (last week of March), will only cause the temp data to lose credibility.

It does lead me to ask a question. Is there anyone here on BAUT who had hotter weather than normal for the last year?

Houston has been cooler and alot more windy than usual.

aurora
2009-Apr-02, 03:52 PM
We had a hotter summer than normal last summer.

And we are setting records with glacier shrinkage.

We had a cooler month than normal in March, but that is evidence of short term variation and how that should not be used to evaluate long term trends.

geonuc
2009-Apr-02, 03:53 PM
It does lead me to ask a question. Is there anyone here on BAUT who had hotter weather than normal for the last year?
I think Atlanta was a little warmer last summer, not so much during the cool months.

http://www.wunderground.com/NORMS/DisplayNORMS.asp?AirportCode=KPDK&StateCode=GA&SafeCityName=Atlanta&Units=none&IATA=ATL&lastyear=on&normals=on

Trakar
2009-Apr-02, 04:28 PM
Unfortunately most people's accurate recall of weather and seasonal temperatures is very limited. This is why science relies upon actual records rather than anecdotal impressions. If some people in a given state or area do not understand that regional weather over a given time period can be greatly different than global climate conditions, then I'd say it has more to do with the educational system in that state or region than anything else,..or perhaps one's misguided political biases influencing and distorting their education.

Gillianren
2009-Apr-02, 05:58 PM
Our summers have been getting hotter, I know. Our winters have just been getting weirder--we had snow last month, too, in fact last weekend. But warmer or colder here doesn't mean warmer or colder globally. So what if we're off by a few degrees either way? Washington is a very small place. In fact, North America is a relatively small place.

korjik
2009-Apr-02, 06:29 PM
We had a hotter summer than normal last summer.

And we are setting records with glacier shrinkage.

We had a cooler month than normal in March, but that is evidence of short term variation and how that should not be used to evaluate long term trends.

Where?

korjik
2009-Apr-02, 06:35 PM
Unfortunately most people's accurate recall of weather and seasonal temperatures is very limited. This is why science relies upon actual records rather than anecdotal impressions. If some people in a given state or area do not understand that regional weather over a given time period can be greatly different than global climate conditions, then I'd say it has more to do with the educational system in that state or region than anything else,..or perhaps one's misguided political biases influencing and distorting their education.

Yes, the best way to make an arguement is to call someone an ignorant fool. Or a political fool for that matter.

Do you actually have anything to contribute?

korjik
2009-Apr-02, 06:43 PM
Our summers have been getting hotter, I know. Our winters have just been getting weirder--we had snow last month, too, in fact last weekend. But warmer or colder here doesn't mean warmer or colder globally. So what if we're off by a few degrees either way? Washington is a very small place. In fact, North America is a relatively small place.

technically, by your description, land is a relatively small place. :)

Also, all of global warming over the next century is a few degrees, so someone thinks it matters.

Are your summers drier in addition to warmer?

Gillianren
2009-Apr-02, 06:49 PM
technically, by your description, land is a relatively small place. :)

Well, yes. Yes, it is.


Also, all of global warming over the next century is a few degrees, so someone thinks it matters.

As a global average. A few degrees one way or the other in any one place that's only a couple hundred square miles does not indicate much on a global scale.


Are your summers drier in addition to warmer?

I don't think so, but it's hard to tell in a rain forest. It rains a lot, but is it raining as hard?

Solfe
2009-Apr-03, 01:11 AM
Buffalo, NY seems drier to me, but more often rains. No science, just my recall of the past 10 years or so.

flynjack1
2009-Apr-03, 01:17 AM
Overall I am guessing, and that is what it is, that here in New Mexico we had average temperatures for the length of the winter. It was warmer than usual in January but colder than usual in March. A year may seem an appropriate scale in human thinking, but in climate cycles I really don't think it means much. My one observation that is fairly objective over a large number of years is the following.

Every year for the last 18 I have been elk hunting in September. Most of these years in the exact same camp. With that I can recall my first couple of years we would have a hard frost during the hunt. The kind of frost that when walking through the fields your boots end up soaking wet when the sun rises. This hasn't happened in any of the last 14 years. Convenient but odd just the same.

Trakar
2009-Apr-03, 01:57 PM
Yes, the best way to make an arguement is to call someone an ignorant fool. Or a political fool for that matter.

Do you actually have anything to contribute?

Actually, my statement that science revolves around records and that global climate change is conditional to Global average annual temperature readings, seems to be a quite relevent and necessary contribution given much of the anecdotal-based commentary which preceded my statements.

Perhaps you can name which specific people or side of the argument I painted with that brush of your assertions?

geonuc
2009-Apr-03, 02:14 PM
Actually, my statement that science revolves around records and that global climate change is conditional to Global average annual temperature readings, seems to be a quite relevent and necessary contribution given much of the anecdotal-based commentary which preceded my statements.
Well, although not the OP, korjik did ask for individual experiences, which is what most people subsequently were responding to. And I provided a link to local temperature records for my area.

Essan
2009-Apr-03, 02:24 PM
This Winter we broke cold records almost everywhere, Russia, Alaska, Yukon, Prairies, Europe, Marocco, Northern India, China.

Actually we broke warm records in some places, including India (http://timesofindia.indiatimes.com/Lucknow/Weatherman_says_hot_winter_to_continue/articleshow/4185802.cms) and China (http://www.philstar.com/Article.aspx?articleId=444600&publicationSubCategoryId=200) ;)

And most of the USA (http://www.noaanews.noaa.gov/stories2009/20090310_winterstats.html) was average or above average.

Stroller
2009-Apr-04, 06:35 PM
Actually, my statement that science revolves around records and that global climate change is conditional to Global average annual temperature readings, seems to be a quite relevent

The questions I have regarding the global temperature indices are:

1) Why does the organisation which supplies GISS and HADcru with their data (USHCN) apply upward adjustments to the data over time?

This graph shows the difference between the raw and final data.
http://cdiac.ornl.gov/epubs/ndp/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif

2) Why has the HADcru global temperature average departed from the HADcru sea surface measurements since 1980 when they correlated so closely before?
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1900/mean:43/plot/hadsst2gl/from:1900/mean:43

3) Why does GISS not compensate for the urban heat island effect since it lost the majority of it's rural stations?

4) Why is there an increasing divergence between the Surface based GISS and HADcru series from the satellite based indices UAH and RSS?
http://www.woodfortrees.org/plot/gistemp/from:1979/mean:12/offset:-0.2/plot/uah/mean:12

I'd be interested in any answers to these questions the members of the forum can provide.

raptorthang
2009-Apr-04, 07:00 PM
Folks are always saying 'back when I was...blah...blah..." We all feel the same way until we look at actual records and nothing has changed all that much. Back when we were 'ten' years old or 'five' or 'twenty' or 'whatever' we remember the hilites...the day our feet froze waiting for the bus and the snow was over the fence height, etc. We don't remember the hundred days either sie of that day when things were quite unremarkable.

The world is not confirmed to be heating or cooling or neither because of anecdotal stories that don't have some actual science on the bones. As one looks back one realizes that the walk to school wasn't as far as it seemed, the the pond we swam in wasn't so deep,and, if we look at weather records, the snow was rarely as high as the fence.

Gillianren
2009-Apr-04, 07:30 PM
Especially where I grew up.

Trakar
2009-Apr-04, 07:39 PM
Well, although not the OP, korjik did ask for individual experiences, which is what most people subsequently were responding to. And I provided a link to local temperature records for my area.

Agreed, I simply stated that individual and local experiences (and more importantly the memories and perceptions of those experiences) are largely useless in assessing global averages and rates of change. Again, it may not be in line with the original poster's request, but it is addressing that request and relevant to the discussion of the OP's request.

raptorthang
2009-Apr-04, 08:06 PM
The temperture in my part of Canada has raised an averge of .4 of one degree celsius this century. I for one can't tell if it's 12c outside or 12.4c. I'd be lucky to guess within 3 or 4 degrees.

Also, the global warming is an average (est, vary from .29 of a degree to .75 of a degree over the last century) so that not everywhere can be 'so warm' to be a perceptual difference. If some place is over the average of increase for the world then some other place is under. Rarely hear anyone say 'Gee, it's a lot colder than when I was young'...but it has to be 'somewhere'.

2 + 2 + 2 +2 = 8 (divided by 4 = 2 average)

4 +3 + 4 + ?...gives an average of 2...(hint...it's not a positive number)

If it's perceptually warmer where you live then it's has to be preceptually colder over the century in other places. It's more likely the difference in temperature is really too small for anyone to notice except through cherry picking anecdotal memories.

Trakar
2009-Apr-04, 09:23 PM
The questions I have regarding the global temperature indices are:

1) Why does the organisation which supplies GISS and HADcru with their data (USHCN) apply upward adjustments to the data over time?

http://www.ncdc.noaa.gov/oa/climate/research/ushcn/


2) Why has the HADcru global temperature average departed from the HADcru sea surface measurements since 1980 when they correlated so closely before?

Not sure what you are asking here, there are the Had(ley)C(limate)R(esearch)U(nit) - 1,2 or 3 datasets which refer to various global averages derived from the blended CRUTEM3 land-surface air temperature dataset and the HadSST2 sea-surface temperature dataset. I'm afraid you'll have to more properly characterize your question before I could offer a response.


3) Why does GISS not compensate for the urban heat island effect since it lost the majority of it's rural stations?

http://pubs.giss.nasa.gov/docs/2001/2001_Hansen_etal.pdf

http://www.ncdc.noaa.gov/oa/wmo/ccl/rural-urban.pdf

http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2FJCLI3730.1

http://www.agu.org/pubs/crossref/2008/2008JD009916.shtml


4) Why is there an increasing divergence between the Surface based GISS and HADcru series from the satellite based indices UAH and RSS?

http://tamino.wordpress.com/2008/01/24/giss-ncdc-hadcru/


I'd be interested in any answers to these questions the members of the forum can provide.

http://www.aip.org/history/climate/20ctrend.htm

nauthiz
2009-Apr-04, 09:53 PM
1) Why does the organisation which supplies GISS and HADcru with their data (USHCN) apply upward adjustments to the data over time?

This graph shows the difference between the raw and final data.
http://cdiac.ornl.gov/epubs/ndp/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif
I'm guessing if you track down the article that that graph came from, it will explain the adjustments. I know quite a lot of different adjustments are made to get from the raw data to the traditional data, and since that graph appears to come from an official document it might be accompanied by other information that helps attribute the adjustments.


2) Why has the HADcru global temperature average departed from the HADcru sea surface measurements since 1980 when they correlated so closely before?
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1900/mean:43/plot/hadsst2gl/from:1900/mean:43
The difference has gone from about zero to what looks like a bit less than 0.05 degrees on average. It could be something as simple as that differences in instrumentation technology means that the measurements made prior to that time simply weren't precise enough to resolve such a small difference.



3) Why does GISS not compensate for the urban heat island effect since it lost the majority of it's rural stations?
One of the major adjustments that USHCN does to get from the raw data to the final data is to compensate for the urban heat island effect.


4) Why is there an increasing divergence between the Surface based GISS and HADcru series from the satellite based indices UAH and RSS?
http://www.woodfortrees.org/plot/gistemp/from:1979/mean:12/offset:-0.2/plot/uah/mean:12
Well, for starters, it's not exactly an apples-to-apples comparison so we shouldn't necessarily expect them to be railroaded together. Different groups use different techniques based on radiance in different frequencies and equipment with different quirks in order to produce their data. If I'm remembering right GISTEMP and UAH/RSS aren't even measuring the temperature of the same thing - GISTEMP is a surface index whereas UAH/RSS are troposphere indices. It shouldn't be all that surprising that two very different thermometers measuring two different things might disagree by 0.1-0.2ļC.

Stroller
2009-Apr-04, 10:39 PM
Trakar, thanks for the links, I'll study those which relate to my questions.

The Tamino link doesn't seem to deal with satellite data in comparison to land based though, and the final link is a text on global warming theory rather than a study on temperature measurement.

Thanks again anyway.

Nauthiz, Hi.

"One of the major adjustments that USHCN does to get from the raw data to the final data is to compensate for the urban heat island effect."

I'm having difficulty working out how they do that when the data is adjusted *upwards* for more recent times, as per the graph I linked. Maybe the USHCN doc Trakar linked will shed some light.

"GISTEMP is a surface index whereas UAH/RSS are troposphere indices. It shouldn't be all that surprising that two very different thermometers measuring two different things might disagree by 0.1-0.2ļC"

Sure. I have my own ideas on this one. During the warming period 1980-2003, the atmosphere was warm in relation to the land and ocean. Since the planet started cooling down again in 2003, the atmosphere is losing heat to space and the land/ocean is lagging a bit. It's confusing though, because changes in sea temps tend to lead atmospheric temps by a varying number of months, 3-5 or so.
If you have a look at this you'll see what I mean:
http://www.woodfortrees.org/plot/hadsst2gl/from:2003/offset:-0.2/mean:3/plot/uah/from:2003/scale:0.5/mean:3

lomiller1
2009-Apr-05, 02:16 AM
Why does the organisation which supplies GISS and HADcru with their data (USHCN) apply upward adjustments to the data over time?

The adjustments are well documented. The largest is the time of day adjustment.

http://www.ncdc.noaa.gov/oa/climate/research/ushcn/ushcn.html





The data for each station in the USHCN are subjected to the following quality control and homogeneity testing and adjustment procedures.

1. A quality control procedure is performed that uses trimmed means and standard deviations in comparison with surrounding stations to identify suspects (> 3.5 standard deviations away from the mean) and outliers (> 5.0 standard deviations). Until recently these suspects and outliers were hand-verified with the original records. However, with the development at the NCDC of more sophisticated QC procedures this has been found to be unnecessary.

2. Next, the temperature data are adjusted for the time-of-observation bias (Karl, et al. 1986) which occurs when observing times are changed from midnight to some time earlier in the day. The TOB is the first of several adjustments. The ending time of the 24 hour climatological day varies from station to station and/or over a period of years at a given station. The TOB introduces a non climatic bias into the monthly means. The TOB software is an empirical model used to estimate the time of observation biases associated with different observation schedules and the routine computes the TOB with respect to daily readings taken at midnight. Details on the procedure are given in, "A Model to Estimate the Time of Observation Bias Associated with Monthly Mean Maximum, Minimum, and Mean Temperatures." by Karl, Williams, et al.1986, Journal of Climate and Applied Meteorology 15: 145-160.

3. Temperature data at stations that have the Maximum/Minimum Temperature System (MMTS) are adjusted for the bias introduced when the liquid-in-glass thermometers were replaced with the MMTS (Quayle, et al. 1991). The TOB debiased data are input into the MMTS program and is the second adjustment. The MMTS program debiases the data obtained from stations with MMTS sensors. The NWS has replaced a majority of the liquid-in-glass thermometers in wooden Cotton-Region shelters with thermistor based maximum-minimum temperature systems (MMTS) housed in smaller plastic shelters. This adjustment removes the MMTS bias for stations so equipped with this type of sensor. The adjustment factors are most appropriate for use when time series of states or larger areas are required. Specific details on the procedures used are given in, "Effects of Recent Thermometer Changes in the Cooperative Network" by Quayle, Easterling, et al. 1991, Bulletin of the American Meteorological Society 72:1718-1724.

4. The homogeneity adjustment scheme described in Karl and Williams (1987) is performed using the station history metadata file to account for time series discontinuities due to random station moves and other station changes. The debiased data from the second adjustment are then entered into the Station History Adjustment Program or SHAP. The SHAP allows a climatological time series of temperature and precipitation adjustment for station inhomogeneities using station history information and is the third adjustment. The adjusted data retains its original scale and is not an anomaly series. The methodology uses the concepts of relative homogeneity and standard parametric (temperature) and non parametric (precipitation) statistics to adjust the data. In addition, this technique provides an estimate of the confidence interval associated with each adjustment. The SHAP program debiases the data with respect to changes other than the MMTS conversion to produced the "adjusted data". Specific details on the procedures used are given in, "An Approach to Adjusting Climatological Time Series for Discontinuous Inhomogeneities" by Karl, and Williams, Jr. 1987, Journal of Climate and Applied Meteorology 26:1744-1763.

5. Estimates for missing data are provided using a procedure similar to that used in the homogeneity adjustment scheme in step three. This fourth adjustment uses the debiased data from the third adjustment (SHAP) and fills in missing original data when needed (i.e. calculates estimated data) based on a "network" of the best correlated nearby stations. The FILNET program also completed the data adjustment process for stations that moved too often for the SHAP program to estimate the adjustments needed to debias the data.

Each of the above adjustments is done is a sequential manner. The areal edits are preformed first and then the data are passed through the following programs (TOBS, MMTS, SHAP and FILNET). At the end of each program, a dataset is produced and the graphs below show the annual temperature departures for each of the adjusted values.

6. The final adjustment is for an urban warming bias which uses the regression approach outlined in Karl, et al. (1988). The result of this adjustment is the "final" version of the data. Details on the urban warming adjustment are available in "Urbanization: Its Detection and Effect in the United States Climate Record" by Karl. T.R., et al., 1988, Journal of Climate 1:1099-1123.

Stroller
2009-Apr-05, 07:42 AM
From Lomiller1's link

"1950 to 1980. During this time, many sites were relocated from city locations to airports and from roof tops to grassy areas. This often resulted in cooler readings than were observed at the previous sites. When adjustments were applied to correct for these artificial changes, average US temperature anomalies were cooler in the first half of the 20th century and effectively warmed throughout the later half. Filling in missing data (blue line) produced cooler temperatures prior to 1915. Adjustments to account for warming due to the effects of urbanization (purple line) cooled the time series an average of 0.1F throughout the period of record."

A visit to www.surfacestations.org will help clue us up on what's up with the surface station situation. A lot are poorly sited, and don't meet USHCN guidelines.
Issues with data cable lengths on the newer type stations mean a lot of the staions are now located much closer to buildings, aircon exhausts and parking lots. These strongly affect readings.

nauthiz
2009-Apr-05, 03:02 PM
"One of the major adjustments that USHCN does to get from the raw data to the final data is to compensate for the urban heat island effect."

I'm having difficulty working out how they do that when the data is adjusted *upwards* for more recent times, as per the graph I linked. Maybe the USHCN doc Trakar linked will shed some light.

I don't think heat island compensation is the dominant adjustment, so if you're looking at a graph of overall averages most other factors would dominate what you see.

Was it discussed in the source where you got that graph?

lomiller1
2009-Apr-05, 07:09 PM
Best not to visit Surfacestation.org, it better to stick to science. Surfacestation.org is the equivalent of creationists trying to deny the fossil record. As per the previous links the trend towards urbanization is removed from the surface station data, so it’s a non-issue.

Stroller
2009-Apr-06, 09:17 AM
Surfacestation.org is the equivalent of creationists trying to deny the fossil record.
Back to the ad hominem argument I see.

Stroller
2009-Apr-06, 09:19 AM
I don't think heat island compensation is the dominant adjustment
Clearly not, I agree.

captain swoop
2009-Apr-06, 03:45 PM
Nope, looking at the site I would say he is spot on.

lomiller1
2009-Apr-07, 03:36 AM
Back to the ad hominem argument I see.

You stop appealing to false authority and Iíll stop pointing out they are not legitimate experts.

lomiller1
2009-Apr-07, 03:41 AM
I don't think heat island compensation is the dominant adjustment, so if you're looking at a graph of overall averages most other factors would dominate what you see.

The problem with heat island effects is that they donít inject a trend into individual sites. You get a sudden increase when the area is built up, then possibly a slow decrease as trees, vegetation etc grow subsequently. For an individual site what you are most likely to see from development is a sudden increase in temp followed by a look cooling trend.

Klausnh
2009-Apr-07, 02:35 PM
The problem with heat island effects is that they donít inject a trend into individual sites. You get a sudden increase when the area is built up, then possibly a slow decrease as trees, vegetation etc grow subsequently. For an individual site what you are most likely to see from development is a sudden increase in temp followed by a look cooling trend.
If I understand this (http://data.giss.nasa.gov/gistemp/) correctly, I believe they are.

The GHCN/USHCN/SCAR data are modified in two steps to obtain station data from which our tables, graphs, and maps are constructed. In step 1, if there are multiple records at a given location, these are combined into one record; in step 2, the urban and peri-urban (i.e., other than rural) stations are adjusted so that their long-term trend matches that of the mean of neighboring rural stations. Urban stations without nearby rural stations are dropped.

nauthiz
2009-Apr-07, 03:08 PM
So where do we get this idea that there's no compensation for the heat island effect?

Klausnh
2009-Apr-07, 04:30 PM
So where do we get this idea that there's no compensation for the heat island effect?From blogs spreading misinformation.

lomiller1
2009-Apr-07, 09:39 PM
From blogs spreading misinformation.

Basically.

As with any science there exists the possibility that either the method or process for removing the UHI effect is incorrect, but you wonít prove this by photographing individual stations. If you want to argue UHI isnít correctly addressed you need to either

a) reproduce the process described in the literature and show you get different results and publish in a respected journal
b) publish your own process + results and show itís superior and publish in a respected journal

Since the people complaining about the published literature donít want to produce any science of their own they will never do either of these.

nauthiz
2009-Apr-07, 10:00 PM
There seems to also be a tacit understanding that good science is never dirty, and therefore any scientific conclusion that's based on data that isn't the stuff of dreams is invalid.

The UHI-related arguments against AGW that I see tend to take the form of "There's uncertainty in the data, therefore the data is complete garbage." The approach I see in actual science tends to be more along the lines of "There's uncertainty in the data, so let's quantify that uncertainty so we have a decent idea of how much precision and accuracy we're working with."

I like the latter approach better. The former reminds me of the kind of thinking that prompted the joke about how every new discovery in the fossil record doesn't really fill in a missing link, it just creates two new ones on either side.

That, and being unaccustomed to noisy data and how to work with it strikes me as being a bit out of place on a forum that's devoted to a field where you're in pretty good shape if your error bars only cover an order of magnitude.

Ari Jokimaki
2009-Apr-08, 02:46 PM
It's curious that no data seems to be accurate enough to show global warming, but everything seems to be accurate enough to show global cooling. Shouldn't there be only one standard?

nauthiz
2009-Apr-08, 03:11 PM
I don't think the warming trend over the past century is really under dispute. It seems that oftentimes it's more a question of whether a carbon and two oxygens stuck together will always interact with photons the same way, or if it somehow knows to behave differently if those atoms got stuck together because of something humans did.

Gillianren
2009-Apr-08, 04:52 PM
I don't think the warming trend over the past century is really under dispute.

I've seen it disputed.

Trakar
2009-Apr-08, 10:36 PM
I don't think the warming trend over the past century is really under dispute. It seems that oftentimes it's more a question of whether a carbon and two oxygens stuck together will always interact with photons the same way, or if it somehow knows to behave differently if those atoms got stuck together because of something humans did.

http://www.bgc.mpg.de/service/iso_gas_lab/publications/PG_WB_IJMS.pdf

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Ch02.pdf

http://www.realclimate.org/index.php?p=87

http://cait.wri.org/figures.php?page=/World-FlowChart

nauthiz
2009-Apr-08, 11:00 PM
http://www.bgc.mpg.de/service/iso_gas_lab/publications/PG_WB_IJMS.pdf

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Ch02.pdf

http://www.realclimate.org/index.php?p=87

http://cait.wri.org/figures.php?page=/World-FlowChart

:eek:

So what should I be looking for in this linkbomb?

flynjack1
2009-Apr-09, 12:37 AM
I think when and if there is an agreed upon standard for measuring Earths temperature, it will makes matters much better. As it stands there are a number of different measurements, and none of them using the same exact methodology. Each time you change the way you make measurements and add datum points to the data you make it more difficult to compare to previous data without error. We may for example be getting the best measurements yet, but what of those taken 100 years ago?

nauthiz
2009-Apr-09, 05:19 AM
I've seen it disputed.

I think I just did. I stand corrected.

Stroller
2009-Apr-09, 12:25 PM
Basically.

As with any science there exists the possibility that either the method or process for removing the UHI effect is incorrect, but you wonít prove this by photographing individual stations. If you want to argue UHI isnít correctly addressed you need to either

a) reproduce the process described in the literature and show you get different results and publish in a respected journal
b) publish your own process + results and show itís superior and publish in a respected journal

Since the people complaining about the published literature donít want to produce any science of their own they will never do either of these.

http://www.surfacestations.org/
"Surfacestations project reaches 70% of the network surveyed. 854 of 1221 stations have been examined in the USHCN network."

Hardly 'taking the occasional photo here and there.

http://www.climateaudit.org/?p=4901



"Neither CRU nor NOAA have archived any source code for their calculations, so it is impossible to know for sure exactly what they do. However, I am unaware of any published documents by either of these agencies that indicate that they "correct" their temperature index for UHI effect.

The most recent exposition of CRU methodology is Brohan et al 2006, which stated in respect to UHI that they included an allowance of 0.1 deg C/century in the uncertainty, but does not describe any "correction" to the reported average temperature.

Unlike CRU and NOAA, GISS makes a decent effort to adjust for UHI in the U.S. (outside the USA, its efforts are risible.) A few days ago, I showed the notable difference between the GISS (UHI-adjusted) version in the US and the NOAA unadjusted version, where the difference is much more than 0.1 deg C/century asserted by CRU/NOAA.

http://http://1.2.3.9/bmi/www.climateaudit.org/wp-content/uploads/2009/01/noaa_vs_nasa.gif
http://1.2.3.9/bmi/www.climateaudit.org/wp-content/uploads/2009/01/noaa_vs_nasa.gif

surfacestations.org has made a concerted effort to identify high-quality stations within the USHCN network (CRN1-2 stations) and preliminary indications are that the GISS U.S. estimate will not differ greatly from results from the "best" stations (though there will probably be a little bias.)

This does not prove that CRU and NOAA estimates are any good. Quite the contrary. It shows that the CRU and NOAA failures to make UHI adjustments along the lines of GISS are introducing a substantial bias in these records."

So, it is not possible to "reproduce the process described in the literature", because the process is not described in the literature.

Phase 2 of the surfacestations.org project will be to construct a temperature series from the stations they have identified as reliable through empirical groundwork. This will likely be for the US only initially.

lomiller1
2009-Apr-09, 04:00 PM
Independent reproduction should avoid using or even looking at existing source code whenever possible. That’s just replicates errors. The code itself has been reported to be reproducible with a few pages of MathCad so is someone has an issue they should be writing their own code and publishing their results.

Surfacestation.org isn’t interested in doing either, they simply take pitchers of sites which is entirely worthless for climate studies because it’s only point in time and tells you nothing about what the site looked like over the years. Knowing there is a paved road near a site is useless unless you know if that road was there 50 years ago. If the road was there 50 years ago is has no impact whatsoever on the climate trends.

I’m unsure of whether you are quoting or saying you personally don’t know of any papers but either way why didn’t you think to check the GISS temp homepage? The relevant papers are easily obtainable.

Urban effects were added to the analysis in 1999
http://pubs.giss.nasa.gov/docs/1999/1999_Hansen_etal.pdf
and refined in 2001
http://pubs.giss.nasa.gov/docs/2001/2001_Hansen_etal.pdf

nauthiz
2009-Apr-09, 04:05 PM
Leaving all that aside for a moment, I have a simpler question:

If you're not happy temperature measurements taken from ground stations, why not look at satellite data such as RSS and UAH instead? Your average satellite in orbit tends to be quite a few kilometers away from the nearest city.

lomiller1
2009-Apr-09, 05:32 PM
Leaving all that aside for a moment, I have a simpler question:

If you're not happy temperature measurements taken from ground stations, why not look at satellite data such as RSS and UAH instead? Your average satellite in orbit tends to be quite a few kilometers away from the nearest city.


You need to have both. Satellites donít measure surface temperature they measure lower troposphere temperature, which is similar but not the same. The satilite record also, only goes back to the late 70's which limtis it.

I do find it interesting to see some people totally ignore RSS in favor of UAH. The two use the same base data but crunch the numbers differently. RSS gets similar numbers to the ground station based analysis (in fact it shows a slightly larger trend) while UAH shows the smallest trend and has a history of errors.

nauthiz
2009-Apr-09, 06:01 PM
Well, granted. But I wasn't really trying to argue that that approach would produce better science. I was just wanting to focus on the UHI criticism itself, and point in the direction of an empirical comparison.

Assuming that there is a fairly strong correlation between satellite measurements of lower troposphere temperature and ground measurements - and one of the graphs that Stroller posted earlier would seem to confirm that this is the case - then presumably a comparison of the two sets of data can give us a rough upper limit on the extent to which station placement could be distorting the mean surface temperature data. An eyeball estimate suggests that that limit is in the neighborhood of 0.1C. In other words, that rough analysis (which, for all its faults, is still more in-depth and empirically-driven than what has been presented on the anti-AGW side) would seem to suggest that even in the absolute worst case the UHI is hardly the bomb that it's being made out to be.

But, like I said, that little back-of-the-envelope experiment is pretty poor. It'd be better to look at more rigorous analyses (http://www.skepticalscience.com/urban-heat-island-effect.htm).

JESMKS
2009-Apr-09, 10:53 PM
It seems that most of the concern on global warming has been related to CO2 emissions. Do the climatic models consider the tremendous improvement in air quality that has occured during the past 60 years? Most particulate emissions have been eliminated which has reduced smog, haze and cloud cover and should have reduced solar reflection and contributed to global warming.

nauthiz
2009-Apr-09, 11:11 PM
Yup - over in the "skepticism by 650" thread, for example, there was some discussion on a recent AOGCM-based study that indicates that a very large part of the arctic warming we've seen recently is due to reductions in anthropogenic aerosol emissions.

Ari Jokimaki
2009-Apr-10, 05:28 AM
CRU calculations are documented in Brohan et al. (2006) (http://www.cru.uea.ac.uk/cru/data/temperature/HadCRUT3_accepted.pdf) and in Folland et al. (2001) (http://www.geog.ox.ac.uk/~mnew/teaching/Online_Articles/folland_et_al_temp_uncertainties_GRL_2001.PDF), so the process of calculations is described in literature. Target audience for this type of literature is scientists, so the papers are not written so that everyone can repeat them just like that without studying the issue deeply. It is not fault of Brohan & Folland et al. if some wanna-be-climate-scientists cannot reproduce the calculations without someone holding their hands and showing how to do it.

As for urbanization effects, see for example Figure 10 of Brohan et al. (2006), it shows the effect of bias errors in blue, and bias error contains urbanization effects. Big deal is made by denialists about CRU not making urbanization corrections to the temperature but to the uncertainty. What I am missing here is that what is the problem with including the corrections to uncertainty? After all, effect of urbanization is an uncertainty for the temperature, especially as Brohan et al. (2006) explain that metadata necessary to correct all the stations since 1850 is not available. In a case like that, it is not a bad idea to estimate the possible effect and include it as uncertainty. That is what is done in CRU's case.

Ari Jokimaki
2009-Apr-10, 05:40 AM
It seems that most of the concern on global warming has been related to CO2 emissions. Do the climatic models consider the tremendous improvement in air quality that has occured during the past 60 years? Most particulate emissions have been eliminated which has reduced smog, haze and cloud cover and should have reduced solar reflection and contributed to global warming.
See the Figure 2 of Lean & Rind (2008) (http://pubs.giss.nasa.gov/docs/2008/2008_Lean_Rind.pdf). The inset of figure 2d shows a simple example of how human-based aerosols are considered in climate models. Effect of aerosols is shown with blue line in that figure. You see that there's a growing trend of cooling that continues to 1980's and then starts to settle. That settling is the reduced aerosol emissions, so the reduction in aerosol emissions doesn't contribute to global temperatures dramatically just yet, and the total aerosol effect is still strongly negative (causes cooling).

Ari Jokimaki
2009-Apr-10, 05:42 AM
If you're not happy temperature measurements taken from ground stations, why not look at satellite data such as RSS and UAH instead?
What? And spoil perfectly good conspiracy theories?

Stroller
2009-Apr-10, 07:13 PM
Yup - over in the "skepticism by 650" thread, for example, there was some discussion on a recent AOGCM-based study that indicates that a very large part of the arctic warming we've seen recently is due to reductions in anthropogenic aerosol emissions.

So after we take account of the 45% down to the reduction of particulate emissions, and allow for the strong solar cycles in the second half of the C20th, and the changing wind patterns which drove more ice out of the arctic according to NASA, how much room is left for a co2 effect?

Trakar
2009-Apr-10, 08:41 PM
:eek:

So what should I be looking for in this linkbomb?

Essentially these are links which illustrate the primary diffence between human generated CO2 and natural CO2, and why such is relevent to the current climate warming process. Whether the argument of CO2 by man or nature is yours, or merely faced by you, the links provided supply an ample amount of supportive empiric evidences describing the distinction and why human generated CO2 is a cornerstone factor in the current climate-change event.