This story from the Hockey Schtick is a verification of an analysis on WUWT from Bob Tisdale: No Consensus among Three Global Precipitation Datasets
According to a paper published today in Atmospheric Science Letters, global precipitation has either decreased, increased, or not changed over the past 30 years, depending upon which of 3 global datasets are examined:
“Decadal trends of global precipitation are examined using the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP), Global Precipitation Climatology Project (GPCP), and National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. The decadal trends of global precipitation average diverge a decreasing trend for the CMAP data, a flat trend for the GPCP data, and an increasing trend for the reanalysis data.”
Thus, the actual trend of global precipitation, if any, remains a mystery. Several peer-reviewed papers have shown climate models are unable to simulate decadal trends in precipitation, unable to simulate regional trends in precipitation, and that the claim “wet gets wetter, dry gets drier” is without basis.
The paper:
Decadal trends of global precipitation in the recent 30 years
Xiaofan Li et al
Abstract:
Decadal trends of global precipitation are examined using the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP), Global Precipitation Climatology Project (GPCP), and National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. The decadal trends of global precipitation average diverge a decreasing trend for the CMAP data, a flat trend for the GPCP data, and an increasing trend for the reanalysis data. The decreasing trend for the CMAP data is associated with the reduction in high precipitation. The flat trend for the GPCP data is related to the offset between the increase in high precipitation and the decrease in low precipitation. The increasing trend for the reanalysis data corresponds to the increase in high precipitation.
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“increasing, decreasing, & not changing”
We can improve the estimate by averaging out the uncertainty: +1, -1 and 0.
So my best guess (without doing any real research) is that it is not changing.
I think they might have attempted to justify the continuing “significant adjustments”, but I am positive that the did not, in fact, justify that odious, un-scientific practice over at nasa.
rogerthesurf says:
June 27, 2014 at 10:38 pm
ANDYZ You are kidding right?
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Very much so xD
A “consensus” of disagreement. No two agree.
Geoff Sherrington:
Should there also be corrections to the temperature readings to account for wind speed and direction, length of daylight, cloud cover, the average gum leaf intake of nearby koalas? Why stop at rainfall?
/sarc
Aren’t the temp readings supposed to record the temp due to the weather at the recording location? Removing the weather factors seems to be counter-productive.
It appears one can use any variation of factors to reach the conclusion one is looking for.
Geoff Sherrington says:
June 28, 2014 at 3:13 am
Colleagues here in Australia are working on a correlation between rainfall at a site and its maximum daily temperature. At sites so far examined in detail, the conclusion seems to be that “water cools”.
The correlation is not shown yet to be causation, but it is strong and large.
It is plausible that temperatures might need adjustment for rainfall before they are to be used for certain purposes. If it is not already catered for, one example of a need for rainfall-corrected data sets would be estimation of climate sensitivity. Another would be the calibration of tree ring proxies, which might be better done after removal of a known growth agent, namely rainfall, from the temperature data used for calibration.
Water as vapor and droplets raises the enthalpy of the air so a volume of air with increased enthalpy can carry more heat before rising in temperature. So the amount of heat in the atmosphere may remain constant as temperature varies with the amount of water. Temperature is the incorrect metric for measuring heat retention due to radiative gases. This does not prevent climate ‘scientists’ playing games with TOB etc., which just demonstrates even less understanding of meteorology and physics.
Theoretically a warming world is a wetter world due to an increase in evaporation and sea surface area. How one can state that increases in precipitation will only appear in regions that are already receiving excessive rainfall, with none or little going to drought areas, is frustratingly beyond my understanding. Is there actually any theory or evidence that could support such an apparent ridiculously assertion? Anyone? GK
“…study finds global precipitation is increasing, decreasing, & not changing”
Even worse than that,
I’ve heard that the climate is changing!
charles nelson says:
June 28, 2014 at 3:00 am
Bob, over the past few days I have witnessed many of the ‘big hitters’ here at WUWT justify significant adjustments made by nasa in US surface temperatures.
I believe those “big hitters” were providing justification that adjustments need to be made to the raw data but they did not necessarily support the overall methodology used by NASA.
Kudos to Bob’s analyses. Verification is the key to any scientific analyses.
On the other hand there has been a disturbing trend to characterize changing weather as climate. And the alarmists have argued with great circularity that climate change will make the earth both wetter and drier.
Ah well, this one’s gone then. It was fun while it lasted.
The nuances of Chinese culture may allow them to overlook the irony of this report. In keeping with such inscrutability, the grammar employed is… well, challenging. Just try to find the verb in their abstract:
The decadal trends of global precipitation average diverge a decreasing trend for the CMAP data, a flat trend for the GPCP data, and an increasing trend for the reanalysis data.
In my technical world, I consider this a reflection of what I wall “Limits to Knowledge”. The idea is that our ability to understand is always limited by something, be it our sampling, natural variation greater than the trend, or incapacity for seeing connections between more than three parameters at one time.
When I speak of this Limits to Knowledge, I am trying to bring to an end the fruitless over-examination, the “sciencing” something to death when it is time to make a decision. People want certainty, however, and if they can’t have true cerrtainty then they will settle for a well-crafted PowerPoint: three decimal places makes people feel better even when the actual understanding is +/- 50%.
Climate science is not the problem we face, but the human factor of wanting certainty and control when there is neither of each. We conflate passion with knowledge – Michael Mann is the poster-child of pounding the table as proof of being Right. If we insisted that so-called leaders admit upfront what they didn’t know or what they were uncertain about, those leaders know the first fool who claimed that he, and only he, had all the answers, would sweep them at the polls. But not just at the polls, but in the shaving mirror where they would look at themselves and think, “Why couldn’t I be the cool one who knows everything?”
All 3 possibilities are consistent with Climate Change. That is because Climate Change underlying dogma rests on AGW. And as far as AGW adherents believe, “the debate is over. The Science is settled.” In other words “take it on faith” and appeals to authority are the tenents of of Climate Change. It is a religion based on faith.
A few comments asked about the “wet get wetter and dry get drier” meme…
http://hockeyschtick.blogspot.com/2014/05/new-paper-finds-wet-get-wetter-and-dry.html
New paper finds the “wet get wetter and dry get drier” meme is false on local scales
An important paper published today in Hydrology and Earth System Sciences finds the claim that global warming causes wet regions to become wetter and dry regions to become drier is incorrect and “does not hold over water or land.” Instead, the authors find “in terms of P − E [precipitation – evaporation], the climate models do not project that the “wet get wetter and dry get drier” at the local scales that are relevant for agricultural, ecological and hydrologic impacts.”
The “wet get wetter and dry get drier” meme had apparently not been checked on regional scales to which it is applied by the IPCC and climate scientists. According to the authors, “Much of the research on projected climate impacts has been based on an implicit assumption that this CC [Clausius–Clapeyron] relation [the basis for the “wet get wetter and dry get drier” meme] also holds at local (grid box) scales but this has not previously been examined. In this paper we find that the simple latitudinal average CC scaling relation does not hold at local (grid box) scales over either ocean or land.”
According to the paper, “Much public and scientific perception about changes in the water cycle has been based on the notion that temperature enhances E [evaporation]. That notion is partly true but has proved an unfortunate starting point because it has led to misleading conclusions about the impacts of climate change on the water cycle. A better general understanding of the potential impacts of climate change on water availability that are projected by climate models will surely be gained by starting with the notion that the greater the enhancement of E [evaporation], the less the surface temperature increase (and vice versa). That latter notion is based on the conservation of energy and is an underlying basis of climate model projections.” In other words, the climate self-regulates with increases in temperature offset by increases in evaporative cooling [and vice-versa] to maintain temperatures within a homeostatic range.
American Meteorological Society President Dr. Marshall Shepherd tweeted that one of his “toughest challenges” is “Explaining to linear thinkers that dry/drier, wet/wetter is expected. They want either or.” Perhaps this paper will explain to Dr. Shepherd why his superior non-linear thinking needs a reset on the “dry/drier, wet/wetter” meme that had not been verified on local/regional scales prior to the publication of this paper.
See also:
http://hockeyschtick.blogspot.com/2012/11/new-paper-contradicts-ipcc-assumptions.html
http://hockeyschtick.blogspot.com/2012/11/new-paper-finds-models-have-it-wrong.html
http://hockeyschtick.blogspot.com/2013/05/did-we-say-wet-becomes-wetter-and-dry.html
Well I’ll be damn. They actually found a consensus! And 100% to boot! Models consensually agree that the new climate warming theory is this: CO2climate=catastrophicthermocryodroughtydrenchythiswaythatwayupdownsidewayseverywhichwaybutloosestatisticallydisagreeablesupercalafragilisticallyconfirmedtobehumancaused. Hey! My spell checker didn’t underline it! So it must be right.
My new word for CO2 climate didn’t fit on the page. And I can’t remember the rest of it!
charles nelson says:
June 28, 2014 at 3:00 am
…surely we all know now that any such data is open to ‘re-interpretation’?
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I believe the reason the pro CAGW researchers don’t give data and code is because most of their findings are subject to interpretation.
Their findings appear to be driven by activism, opinion and/or self preservation and therefore cannot be re-examined.
cn
The period of net ocean cycles is 64 years. Any data set less than 64 years long is incomplete.
I am one of the few working in the area of rainfall patterns over different parts of the globe. My first paper [published in 1977] relate to the dates of onset over Kerala Coast, an important event in monsoon rains. This showed a 52-year cycle. My second paper relates to Mahalapye in Botswana. The precipitation data presented a 60-year cycle — with sub-multiples, amplitude & phase angles; integrated — published in 1981. The Fortaleza precipitation data in Brazil presented a 52 year cycle — with sub-multiples, phase angles and amplitudes; integrated –. This was published in 1984. 1986 published the analysis of Durban in South Africa and Catuane in Mozambique. The precipitation data of Durban showed 66-year cycle and Catuane 54 years — sub-multiples, amplitude & phase angles integrated –. In the case of Ethiopian stations the analysis was published in 1990. They varied from 22 to 44 years cycles. Asmara in present Eritrea presented 22 year cycle, which is a sub-multiple seen in Durban precipitation. Indian rainfall — all-India southwest monsoon — data analysis was published in 1996 — the homogenized data series was available only in 1995 –. The all-India Southwest Monsoon rainfall presented 60-year cycle — completed two full cycles and started in 1987 the third cycle. This is different in Andhra Pradesh state rainfall that receives rainfall during the southwest and northeast monsoons and cyclonic activity presented 132 year cycle in annual precipitation. The southwest monsoon and northeast monsoon rainfall data presented 56 year cycle but in opposite direction. The cyclonic activity followed the northeast monsoon 56 year cycle pattern. The hurricanes & typhoons followed 60-year cycle of All-India Southwest monsoon but in follow opposite pattern. Global temperature followed the same pattern but similar to typhoons pattern.
In such scenario, average.rainfall pattern provides negative feedback. It is better to look at regional level pattern as they follow general circulation patterns in conjenction with natural in-built cyclic variations.
Dr. S. Jeevananda Reddy
If all the world’s climate scientists were laid end to end, they would point in all directions.
(Apologies to A. Motley)
Incredible, a superposition of three states. I don’t think that’s happened since Schrodinger’s cat and that was only two states. I guess that make CO2 a quantum gas.