Mother Jones news has an “alarming” article called “Our Coming Mega-Drought” in which they say “…virtually all of the world except for China and Russia will experience increased drought by 2030 and severe drought by 2060” and they cite these computer model maps at left.
Yes, it looks pretty bad. But the thing about models, is that they are very sensitive to starting conditions, and like we’ve learned with temperature measurement errors worldwide, so are there errors with precipitation measurement. Rain gauges are easily influenced by wind, and wind eddies. So things like buildings, shrubbery, trees, and station moves can all have an impact. Pierre Gosselin at No Tricks Zone has a good summary of issue related to precipitation measurement which I present below.
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Huge Global Precipitation Deficits Due To Woefully Inaccurate Measurement Techniques!
By P Gosselin on 24. Oktober 2010
NOAA 8 inch rain gage. Source: http://www.crh.noaa.gov/iwx/?n=coop_station
German Weather Service meteorologist Christoph Hartmann writes what I think is a surprising essay on measuring precipitation, and the errors in doing so. Indeed Hartmann says precipitation may be understated by up to 50%, or much more at some locations.
As Hartmann explains, measuring precipitation is by no means an exact science, and results have to be taken with a lump of salt.
There are many sources of errors, and in his essay here he looks at just two main sources: wind and instrumentation.
But first, let’s take a look at how precipitation is measured. In his previous essay he described two types of precipitation measuring gages. In Germany precipitation is measured with the unit of liters/m², e.g. 25.4 liters is an inch of rain.
Two methods of measuring precipitation
Hartman explains that precipitation is generally measured by a rain gage with a known opening area, for example 200 cm² in Germany, which is positioned 1 meter above the ground surface. The gage funnel catches the precipitation and leads it to either
1) a graduated measuring tube or a
2) an optical drop counter
Optical rain gage (drop counting). Source: atmos.washington.edu
With the measuring tube system, the tube is graduated and the amount of precipitation can be simply read off. With the optical rain gage (drop counter), the amount of precipitation is derived from the number of drops. If the precipitation is snow or ice, then the measuring tube or optical gage are brought inside and the captured precipitation is melted and measured.
Hartmann explains that the biggest sources of error are wind-related. This is easily seen when measuring snowfall. Just before a snowflake falls into the gage, air turbulence sucks it back out tosses it overboard. Just taking a look around after a blizzard, it’s easy to imagine how difficult it is to measure snowfall. Places exposed to wind are barren, while other places are covered by meter-deep snowdrifts. How much snow really fell?
Hartmann says measurement errors of up 400% can occur over time when measuring powdery snowfall in alpine, polar or windy areas.
One way to reduce error is to place the instrument in a wind-protected area. By measuring the wind speed, it is then possible to adjust precipitation measurements. But Hartmann writes:
Wind effects lead to an under-estimation of the actual fallen precipitation. The level of deviation depends on the speed of the wind and the type of precipitation.
Because wind speeds are factored into precipitation measurements, climatological precipitation trends without taking changes in wind speeds into account should always be deduced very carefully.
The second problem encountered arise from the two above described measurement instruments, especially with the optical rain gage, writes Hartmann. With frozen precipitation, the gages are heated up in order to melt the precipitation. But this involves evaporation. And under torrential rains, the optical gage becomes much less accurate. The result, writes Hartmann:
Under equal precipitation amounts, the optical gage measures less precipitation than the measuring tube, both in summer and in winter.
So if two different stations use different instruments, them they will show different precipitation amounts even when the actual precipitation is the same. In summary, Hartmann writes his stunning conclusion:
In total these two sources of errors lead to a precipitation deficit of 5 to 15% for liquid precipitation, and between 20 and 50% for solid [frozen] precipitation. In very windy locations, the deficits are substantially more.
Because instruments measure less precipitation than what actually falls, it means we have a worldwide precipitation deficit solely because of the measurement method.
What does it all mean? Are many of the reported droughts solely the product of faulty readings? And we all thought that the network of temperature measurement stations was a mess. This is a huge open floodgate to potential climatological data manipulation and bogus assertions. See here for example: motherjones – the coming mega-drought (h/t NTZ reader DirkH).
They have said quite a few alarmist things in the past.
See “The Thirteenth Tipping Point” [2006].
http://motherjones.com/environment/2006/11/thirteenth-tipping-point
http://motherjones.com/environment/2006/11/thirteenth-tipping-point?page=2
http://motherjones.com/environment/2006/11/thirteenth-tipping-point?page=3
Rainfall measurements over even small distances is quite variable, even when using exactly the same type of equipment.
When doing a trial to determine the feasibility of using treated Kraft pulp mill wastewater for irrigating pastureland, it was essential to know the natural rainfall. The field used was about 150x250m and used 6 rain gauges, one in the centre of the shorter sides and 2 on each of the longer. The closest hills would have been about a Km away and the nearest trees, young pines ~5m tall, about 100m away. The gauges could vary by more than a factor of 2, and there was no constant pattern. A low gauge one time could be the high gauge the next and, from memory, no two gauges ever gave the same reading except when rainfall was non-existent or very low.
Which rain gauge gave the correct reading? Who knows? If 6 gauges within 250m of each other cannot agree then how can any data collected from rain gauges be said to have any degree of either accuracy or precision? The data is possibly accurate to within an order of magnitude but that is all.
I just don’t get this drought issue. Global warming will lead to more water vapour in the atmosphere. Where will it all go? To Russia, China, the Oceans or outer space?
This is a total crock based on a money scam backed up with damned LIES.
Has a published computer model finding ever shown that the future will be better? That no additional funding is needed to study how to forestall doom? Ever? Just once?
Just asking…
I read the mother goose story. Jones. I meant Jones. It was something about the sky is falling. No… not falling. Rain. Yup, that was it, rain not falling. Anyway, they went to see the king… No, I’m mixed up again. They went to pick the king. Not the king, the king’s court. Anyway, some of them got bonked on the head by Acorns which is how they knew the sky… no the rain wasn’t falling. No it was falling now, but soon it wouldn’t be. Really complicated the story, sorry. Anyway, it turned out that only one of them had been bonked on the head by Acorns, the rest were already bonkers, but that isn’t the point, the point is that the rain wasn’t going to fall anymore. But picking a king’s court is no easy task and some of the people who are trying to become courtiers don’t seem worried about the rain not falling because they drink a lot of Tea. Drinking Tea makes you stupid, or maybe being stupid makes you drink Tea, I forget, but the Tea makes you go pee which is like water falling. Way better than Cool-Aid which is fatal sometimes but usually just makes you bonkers. Hallucinagenic I think they call it, if you drink the Cool-Aid it makes you think the sky is falling. Or not falling. No, it was the rain. Rain not falling. If you drink the Tea, the rain won’t fall and we’ll all die. That was it. So all these folks who are bonkers want the king’s courtiers to be bonkers too which is why they started saying that if you drink Tea we’ll all die and proved it with some colorful pictures. Not the kind kids make with crayons, these are much better. They are made of tiny dots and if you just believe in them hard enough, POOF! they become proof. The king himself must have taken a few dots… I mean believed hard enough because he is really upset that some of his new courtiers might be Tea drinkers and who knows which of his plans they will pee on? Rumour is he is angry, in fact livid, the blood pressure has turned his face red. Which is really odd because lot’s of people said he was black but they were only half right, so now that he has turned red, what color is he? The Tea drinkers are adamant that this is the You ESS of Aye where color doesn’t matter but if you put a bit of whiskey in with their Tea they’ll tell you after a couple of cups they figure that was his real color in the first place. But I’m off on a tangent, sorry. Oh yes, the Cool-Aid drinking Acorn bonked little chickens are all afraid the rain won’t fall so they don’t want anyone to pick courtiers who think the rain will fall because they’ll help make the rain not fall by making it warmer which causes water vapour to leap out of the oceans in vast quantities into the sky from which it then doesn’t fall. The dots in the picture prove it if you just believe hard enough. Turns out Daffy Duck was wrong, gravity doesn’t work after all. Well of course he wasn’t made of little dots, not at first, I think they used pencil crayons, so maybe that’s the reason. Point being that I thought the Acorns had gone away, but there still seem to be a lot of people who have been bonked and want all the rest of us to be bonked as well. Bunch of bonkers. If they get their way we’ll all be bonked. Boinked. We’ll all be boinked. And the sky will fall anyway. I mean rain. I mean rainfall. Been drinking beer as I type this and it seems to be wanting to come out the other end so gotta sign off and run go… let some rain fall. I’d say what color but color doesn’t matter in the You ESS of Aye.
Oh wait, I’m in Canada. Dang. Can’t vote. Not much rain here but got snow, lotsa snow. White snow. Well some that’s yellow. Mostly white. Is that why your king doesn’t like us?
[REPLY – May Foxey Loxey eat all your Chicken Licken ~ Evan]
The noise machine is setting up the ground work for what they anticipate might be a cooling trend. If it global temps cool, then they can start talking about drought. Warm-Wet or Cool-Dry, they will always have something to talk about, and its mans fault!
If the 2060-2069 model is correct for the far North, then with that much precipitation the Ice Sheet is advancing. Followed up with Low Pressure cells that duck south of the High Pressure cells that like to park over Ice Sheets. The present deserts would then turn green with the forced weather patterns due to advancing Ice Sheets, and the model is junked.
Actually, calling for “megadrought” is a pretty good call as the past 500 years have been one of the wettest periods in the past several thousand years. So a return to something a little closer to average for the past, oh, 5000 years or so would be a “megadrought” relative to what we perceive as “normal”. It hasn’t been “normal” since Europeans arrived in the Great Basin and far West.
Wait a minute!!! Define drought. The Mother Jones article never says what type of drought. One can have a hydrologic drought- like Lake Meade where a new allocation draws off a million acre-feet/yr more water than is released to it from Lake Powell. We can have a Meteorological drought which is tied to a decline in precipitation and finally an agricultural drought associated with soil moisture, aridity and a particular crops needs.
Drought is a complex subject and often not linked in any meaningful way to climate or precipitation.
Consider the Colorado River drought- in 1903 it delivered some 22,000 ft3/s of water to the head of it’s estuary. By 1934 water irrigation diversions were siphoning 80% of the river’s flows. By the 1950s the Colorado no longer reached the sea drying up its estuary. In 1996 0, nada, zip, zilch zero flow was recorded at the point the Colorado River enters Mexico. I listen in frustration to the media reports on climate change causing a drier western US– the cynic in me asks drier than what -ZERO? And this problem is not going to be fixed by windmills.
Demand precise definition as a first step in any problem discussion.
With all other things equal, a warmer atmosphere should mean more evaporation of water, wherever there is water to evaporate: oceans, lakes, rivers, swamps and anyplace that is wet because it has just rained.
Vegetation also evaporates more water when it is warmer.
Warmer air ->more evaporation – more rain.
Or: CO2 driven global warming ->warmer air -> a larger volume of water constantly being evaporated and raining out.
On the other hand:
If global warming is really going to happen mostly on the North and South Poles and at night, as I have read, then the difference in temperatures between the poles and the equator (which is what drives the wind globally – right?) and between day and night, will diminish, resulting in less wind.
Less wind -> less evaporation – less rain.
When there is no wind, all that warm air does very little evaporating. Air is a very bad conductor of heat, as anybody with double glazing knows.
When there is wind, warmer air gives more evaporation.
Depends if the weather is fully controlled by then. You can see it is already heavily modified.
Hey but in my country
Hot means dry
and cold means wet.
What on earth am I missing?
[REPLY – May Foxey Loxey eat all your Chicken Licken ~ Evan]
I’m waiting for Foxey Loxey to make her move. Foxey wanted to be king but settled for being a courtier and now her job seems to be to go to foreign places on the orders of the king and uhm… rain on them. Unless they’re tyrants of course and then she has to su- be nice to them. I think she still wants to be the king though, and she just might resign after the Tea party has its party to celebrate all the new courtiers and challenge the king for his right to run to be king. Her husband Bill said she would be a queen not a king, but she told him point blank she had a bigger pair than he did and would make a better king which the tea partiers got a chuckle out of, but they want Monica’s number to see if it is true.
mqbec Google ydd pxpbb
Just playing devils advocate here, but won’t they just say that ‘it’s not the absolute value, but the change over time’. So, even though your measuring device measures incorrectly in absolute terms, you will still be able to gleen a rate of change over time. However, from what precip studies I have seen based on observed data there is not much of a longterm trend noted, in spite of supposed warming of the smashingly significant 0.6C this past century.
I take longterm model predictions with a grain of salt and in the NCAR study that I read they put a disclaimer at the bottom of the press release that says this;
“Future drought. These four maps illustrate the potential for future drought worldwide over the decades indicated, based on current projections of future greenhouse gas emissions. These maps are not intended as forecasts, since the actual course of projected greenhouse gas emissions as well as natural climate variations could alter the drought patterns.”
SO WHAT THE HECK IS THE PURPOSE? Why share this with the public? It has no predictive value?….Yes….soooo….then…..huh? Yet the alarmists take it as signed sealed delivered I’m yours!
(shrugs shoulders)
Slightly off topic. NASA has been reseraching rain formation in Finland, it seems that the climate models are somewhat lacking.
http://www.hs.fi/kotimaa/artikkeli/Nasa+haki+Suomesta+tietoa+tihkusateesta/1135261134496
Google translate gives the general idea of the news
Recently, NSW emerged from its long drought. Just as a particularly lethal and expensive quango called the Murray-Darling Basin Authority was publishing its findings that water quotas would have to be drastically and permanently cut, our great western rivers went into flood.
No probs. The Authority still thinks it’s a great idea to wipe out irrigation agriculture and the towns that depend on it. (Large-scale harvesting and damming of water is now, of course, a non-topic.) I’m sure you’re familiar with the terminology of these guys: “environmental flows”, “life of rivers”, “green jobs”, “sustainability”, “long term climate change”. (To be completely fair, those environmental flows of black, de-oxygenated sludge are proving deadly to river life. So it’s not just humans and livestock that are targetted by our green theorists.)
Should eastern Australia return to its mid-century warmer/cooler pattern, there will be plenty of flooding for our model-builders and catastrophists to invoke as proof of Gaia’s wrath. It will be a brief if difficult transition for the poor loves, but, believe me, a good sized Aussie flood will make for better photo-ops than stranded polar bears and groaning glaciers.
Moreover, since you can make a model do anything (except predict or portray accurately), I see a shift in the PDO as a chance for Mann and Hansen to re-invigorate their careers. That whole warming gig is so last century anway.
“…its mid-century warmer/cooler pattern…”
Whoops. I did mean to say wetter/cooler pattern. Do not adjust your models.
As the global average temperature has risen since 1900, I would expect to see more droughts already.
However, looking at the Australian BOM data (http://reg.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi?variable=rain®ion=aus&season=0112) it appears that Australia’s rainfall has been INCREASING since 1900. Australia, being one of the driest countries, should be getting drier according to the Mother jones’ maps.
Re:
Jantar says:
October 24, 2010 at 6:02 pm
I also have one of these (or similar) which uses a balance arm that registers 0.3mm for each movement. We recently had an earthquake and my rain data showed 150mm without any rain falling.
“Australia is the harbinger of change” Tim Flannery climate alarmist extraordinaire (2009).
In April last year, Julie Cart for the L.A. Times wrote a hyperbolic piece on the Australian drought:
‘…the worst drought in more than a century [not so]….prolonged drought and deadly bush fires in the south, monsoon flooding and mosquito-borne fevers in the north, widespread wildlife decline, economic collapse in agriculture and killer heat waves [none of it unprecedented or unpredictable and grossly exaggerated]…… the “accelerated climate crisis” that global warming models have forecast…’:
http://articles.latimes.com/2009/apr/09/world/fg-climate-change-australia9
Well the models didn’t predict the downpours (particularly in the Murray-Darling basin) of the last few months:
http://www.bom.gov.au/jsp/awap/rain/index.jsp?colour=colour&time=latest&step=0&map=anomaly&period=3month&area=nat
(30 year average from 1961 to 1990)
That has been the nature of the Australian climate since European settlement and no doubt from well before:
http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=rranom&area=aus&season=0112&ave_yr=15
The overall global pattern looks similar, with a slight positive trend — some areas receiving more, some less:
http://www.bom.gov.au/cgi-bin/climate/change/global/timeseries.cgi?graph=global_r®ion=global&season=0112&ave_yr=15
Where is the evidence that it has ever been any different?
Yet more numbers, ywt more undefined error bars. The hubris of climate scientist is quite amazing. Just as computers were suppose to cut down on the need to print, but instead made thousands of charts and all writing much easier to produce which lead to much greater printer use, so computers and computer models take thousands of POORLY known and disparately created observations, and numerous POORLY understood physical processes, and arrive at CERTAIN prophecies of global disaster while demanding trillions of dollars NOW, which all sides admit will have NO EFFECT without China and India aboard.
Has anyone thought to post this over at RC? If it was at all believable, it would seem to put a pretty good dent in the whole CO2 driven warming – reinforcing H2O feedback meme. Do you think the lads on the Team could resist the temptation to push another potential catastrophe or are they actually bright enough to realize that by doing so they would be stepping on their own tallywackers?
Yabut, wouldn’t the same error apply in the past so it all cancels out and there really is less precipitation now. Wasn’t it windy during storms from the past, or did they use the string holding the rock hanging from the tree branch to check rainfall?
One of the biggest rainfalls in Portugal last month didn’t even get measured, and then I also detected that the public Institute (INAG) measurements were being given in mm, instead of cm, despite comparisons to nearby stations indicating 10x more rain. Details (in Portuguese) available at http://ecotretas.blogspot.com/search/label/seca
Ecotretas
Meanwhile back to UHI, center of glasgow scotland 10.25pm last night 6 Centigrade, 10 mins later 6 miles out 1 degree centigrade. 35 miles later zero degrees C.