From the Scripps Institute: Saharan and Asian Dust, Biological Particles End Global Journey in California
UCSD, NOAA study is the first to show that dust and other aerosols from one side of the world influence rainfall in another
Scripps Institution of Oceanography / University of California, San Diego
A field study of aerosol impacts on clouds and precipitation in the Sierra Nevada shows that dust and microorganisms transported from as far away as the Sahara desert help to spur the precipitation that California counts on for its water supply.
The CalWater field campaign, funded by the California Energy Commission and led by UC San Diego and NOAA, could help western states better understand the future of their water supply and hydropower generation as climate change influences how much and how often dust travels around the world and alters precipitation far from its point of origin.
“UC San Diego is a leader in addressing complex, multi-disciplinary global challenges, such as water shortages and environmental concerns,” said UCSD Chancellor Pradeep K. Khosla. “Our researchers work collaboratively to investigate and produce meaningful and impactful research that will further our understanding of our planet and environment, so we can improve human life and our world.”
Jessie Creamean, a postdoctoral associate at NOAA’s Earth System Research Laboratory in Boulder, Colo., co-authored the paper appearing in the journal Science with Kaitlyn Suski, a graduate student in the laboratory of Distinguished Chair in Atmospheric Chemistry Prof. Kimberly Prather, who holds appointments at Scripps Institution of Oceanography and the Department of Chemistry and Biochemistry at UCSD.
“We were able to show dust and biological aerosols that made it from as far as the Sahara were incorporated into the clouds to form ice, then influenced the formation of the precipitation in California,” said Creamean, who conducted the fieldwork as a UCSD graduate student under Prather, the study leader. “To our knowledge, no one has been able to directly determine the origin of the critical aerosols seeding mid-level clouds which ultimately produce periods with extensive precipitation typically in the form of snow at the ground.”
The study, “Dust and Biological Aerosols from the Sahara and Asia Influence Precipitation in the Western US,” appears Feb. 28 in online versions of Science.
Researchers have long known that winds can carry aerosols such as dust at altitudes above 5,000 meters (16,400 feet) from continent to continent. An unrelated 2009 study found that in one instance, Asian dust made a complete circuit around the planet in 13 days.
These dust particles can act as ice nuclei within clouds at warmer temperatures than would occur in their absence. They initiate the freezing of water vapor and water droplets, then precipitate as rain, snow, or hail depending on whether meteorological conditions enable them to attain sufficient mass to fall from the sky before evaporating. Without ice nuclei, ice would likely not form in clouds with temperatures above -38 degrees C (-36.4 degrees F).
Besides dust, aerosols can be composed of sea salt, bits of soot and other pollution, or biological material. Bacteria, viruses, pollen, and plants, of both terrestrial and marine origin, also add to the mix of aerosols making the transcontinental voyage.
The researchers’ analysis of winter storms in 2011 found that dust and biological aerosols tend to enhance precipitation-forming processes in the Sierra Nevada. In previous studies, researchers have found that pollution particles have the opposite effect, suppressing precipitation in the Sierra Nevada.
The bulk of the data collected during CalWater came from instruments known as aerosol time-of-flight mass spectrometers (ATOFMS), co-developed by Prather, and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, which tracked the transport of aerosols through the atmosphere from continent to continent. Measurements in and around clouds utilized the Department of Energy’s G-1 research aircraft, which carried other vital instruments, such as a specialized detector for the presence of dust ice nuclei feeding clouds and their presence in the collected residue of ice crystals. That portion of the study was led by co-author Paul DeMott, a senior research scientist at Colorado State University.
Using these tools, the researchers were able to determine that at least some of the dust and bioparticles detected by an aircraft-mounted ATOFMS unit during February 2011 flights through Sierra Nevada storm clouds were in the skies over Oman 10 days earlier, having likely originated in the Sahara a few days earlier. Along the journey, the Saharan dust and microbes mixed with other aerosols from deserts in China and Mongolia before wafting over the Pacific Ocean. Upon arrival in California, the aerosols effectively seeded the storm clouds and contributed to the efficiency of clouds in producing precipitation. Two other transportable ATOFMS units housed in trailers at Sugar Pine Dam just south of Interstate 80 in the Tahoe National Forest and other instruments made further measurements. They determined the chemical composition of aerosols at the end of their journey by looking at the particles present in precipitation samples that were collected during storms.
The researchers said it is a major challenge to sort out the relative impacts of meteorology, atmospheric dynamics, and the original sources of the cloud seeds on precipitation processes. They added that further studies like CalWater are necessary to further identify which aerosols are conducive to precipitation formation and which aerosols stifle its production.
“Due to the ubiquity of dust and co-lofted biological particles such as
bacteria in the atmosphere, these findings have global significance,” the study concludes. “Furthermore, the implications for future water resources become even more substantial when considering the possible increase in [wind-blown] dust as a result of a warming climate and land use changes.”
“Hydropower is an essential source of electricity in California providing, on average, 15 percent of our annual generation. More importantly, it provides electricity during hot summer days when it is needed the most,” said Energy Commission Chair Robert B. Weisenmiller. “This state-funded study in cooperation with NOAA will help us understand how small particles in the air affect precipitation and hydropower generation. Additionally, this information will be useful in estimating the effects of our changing climate.”
Besides Creamean, Suski, and Prather, study coauthors include Daniel Rosenfeld of the Hebrew University of Jerusalem, Alberto Cazorla of UCSD, Paul DeMott of Colorado State University, Ryan Sullivan of Carnegie Mellon University, Allen White, F. Martin Ralph of NOAA, Patrick Minnis of NASA’s Langley Research Center, and Jennifer Comstock and Jason Tomlinson of the Pacific Northwest National Laboratory in Richland, Wash.
# # #
Dust and Biological Aerosols from the Sahara and Asia Influence Precipitation in the Western U.S.
Abstract
Winter storms in California’s Sierra Nevada increase seasonal snowpack and provide critical water resources for the state. Thus, the mechanisms influencing precipitation in this region have been the subject of research for decades. Previous studies suggest Asian dust enhances cloud ice and precipitation (1), while few studies consider biological aerosols as an important global source of ice nuclei (IN). Here, we show that dust and biological aerosols transported from as far as the Sahara were present in glaciated high-altitude clouds coincident with elevated IN concentrations and ice-induced precipitation. This study presents the first direct cloud and precipitation measurements showing that Saharan and Asian dust and biological aerosols likely serve as IN and play an important role in orographic precipitation processes over the western United States.
Science DOI: 10.1126/science.1227279
The SI is here: http://www.sciencemag.org/content/suppl/2013/02/28/science.1227279.DC1/Creamean.SM.pdf
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Aerosols affect cloud formation and persistence, and common observation tells us clouds have a large effect on temperatures.
Today in Perth it got to 34C. 500 km east of here, Kalgoorlie would normally be about 4C hotter than us. But Kalgoorlie didn’t get above 15C today, over 20C colder than normal. Why?
It was cloudy all day there.
Clouds and cloud albedo is the elephant in the climate room. Reduce aerosols and particulates as we have been doing for over 50 years and its no surprise temperatures have risen.
Steven Mosher said:
Next time you see or hear one of these arguments from a skeptic, correct them.
Next time you hear the argument ” oh thats normal” understand: normal has nothing to do with understanding the cause of changes. So, you see those changes in California snow? normal. all normal. you canpoint back millsions of years and find less snow and more snow. But that observation tells you nothing about what causes the wiggles we see. Science like this study gets at the cause. And the same goes for warming. The warming we see is normal. normal on the scale of millions of years. But that observation says nothing about the cause of warming from 1750 to today. To figure that our you have to get beyond the trivially true observation that its “normal” and get to the cause.
————–
Steven Mosher, If you expect to be taken seriously, then you could at least check your spelling and grammar before posting. What you’ve written above makes me cringe. For example, do you understand the proper usage of “effect” vs. “affect?” You, Sir, are a terrible writer. If you want to influence folks then it should begin with writing at a level that at least exceeds a high school graduate. Perhaps you do write well, but you’re being lazy, or maybe you’re so arrogant that you don’t feel the WUWT audience deserves a well-written response.
Steven Mosher said:
Next time you see or hear one of these arguments from a skeptic, correct them.
Next time you hear the argument ” oh thats normal” understand: normal has nothing to do with understanding the cause of changes. So, you see those changes in California snow? normal. all normal. you canpoint back millsions of years and find less snow and more snow. But that observation tells you nothing about what causes the wiggles we see. Science like this study gets at the cause. And the same goes for warming. The warming we see is normal. normal on the scale of millions of years. But that observation says nothing about the cause of warming from 1750 to today. To figure that our you have to get beyond the trivially true observation that its “normal” and get to the cause.
————–
Steven Mosher, If you expect to be taken seriously, then you could at least check your spelling and grammar before posting. What you’ve written above makes me cringe. For example, do you understand the proper usage of “effect” vs. “affect?” You, Sir, are a terrible writer. If you want to influence folks then it should begin with writing at a level that at least exceeds a high school graduate. Perhaps you do write well, but you’re being lazy, or maybe you’re so arrogant that you don’t feel the WUWT audience deserves a well-written response. Which is it?
Probably the biggest effect on global dust levels is the spread of no till farming.
The data show that approximately 35.5 percent of U.S. cropland planted to eight major crops, or 88 million acres, had no tillage operations in 2009.
http://www.ers.usda.gov/publications/eib-economic-information-bulletin/eib70.aspx
Steven Mosher: I like to know about persons like you who are regular commenters on this and other climate science blog. Are you a scientist? Can you link me to your CV, that is one that is not tied in to a social media site, all of which I avoid? I am try to acquire perspective on your views and comments. Thank you.
Latitude
I totally agree re graphs. I am actually a D#####of AGW I don’t believe there has been ANY significant global warming since 1880 CET due to C02 or any human effect. Most of the data has been adjusted to show warming so there LOL
Eliza says:
March 1, 2013 at 1:29 pm
=====
What’s curious is this graph….
…forget CO2 and warming….the question is….why did temps flatline….and why didn’t temps go up as much has they historically have……what stopped it?
Obviously not CO2…….what’s going to stop temps from falling off the clift again?
http://www.foresight.org/nanodot/wp-content/uploads/2009/12/vostok.png
The absolute only “dust” I worry about is the type produced by the Pakistanis,Iranians,and NORKS. Oh. And the sawdust in most climate “sceintists” heads (or lack thereof). And haven’t people noted for centurys that dust drifts across the whole darn planet?
@Mosher: Some people see normal and figure, “this happens all the time — it’s normal — so it’s bound to happen and I don’t care how”, while other people see normal and say, “hmmm, it does this all the time, but how and why?”. Some skeptics sure enough fall into the first camp: “Nothing unusual to see here, move along now!”. But many do not. In fact, I’d venture that before the Climate Consensus ™ formed, most climate scientists were skeptics of the second kind and were looking into how things worked.
Unfortunately, there was an influential, politics-minded group of scientists who reasoned the opposite: “Hmmm, the status quo is boring and I want to be a revolutionary like Darwin or Einstein, and so we need something new to study rather than continuing to refine knowledge of the ‘old stuff’ our predecessors have laid out before us.” And sure enough, decades were dedicated to studying CO2 instead of ozone’s impact on the climate, clouds, ENSO, dust, soot, and a whole host of things that were known for a long time to be important but that was just “old stuff” to the would-be revolutionaries.
So CO2’s been #1 on the charts for decades now, but that old-fashioned black soot recently got a speeding-bullet as it jumped to the #2 spot. It may well be #1 in the Arctic, but no one knows because the money and the prestige goes with the #1 spot and H&M Records heavily back the #1. (DJ’s have gotten fired for attempting to play other hits, don’t you know.)
Anyhow, the bottom line is that skeptics who are skeptics because they listen to talk radio may well be “why investigate something that’s ‘normal’?” camp, but most of the skeptics here and on other skeptical blogs you frequent don’t fall into that camp. I’ll grant that many of them are not in a position to effectively investigate ‘normal’ in the field, but that’s a different matter.
One of the great failures of modern education is its tendency towards specialisation.
Stephen Mosher illustrates this perfectly in one of his snide remarks above, wherein he asks someone to explain the warming trend that began in 1740.
The implication in his statement is that ‘Warming’ began with the Industrial Revolution.
Well Stephen here’s an example of how a few historical facts can neutralise a raft of hysterical presumptions.
In 1740 the Industrial Revolution had only just begun and was limited to parts of Great Britain, pockets of France, regions of what was later to become Germany and tiny portions of Scandinavia.
The combined CO2 outputs of these areas at that time would have been infinitesimally small compared to todays Global output….and yet in your mind Stephen this was enough to set the Global Thermometer rising…way back in 1740!
I recall an interesting statistic, apparently the modern coal port of Newcastle Australia, ships more of the black stuff in one week, than its namesake in the UK shipped in an entire year at the height of the Industrial Revolution.
So I’d be fascinated if you could explain to all us dummies out here, how a few hundred thousand tons of CO2 can trigger measurable global warming in 1740…when the gigatons of CO2 released into the atmosphere over the last 16 years appear to have no warming effect whatsoever?
Perhaps there is some homeopathic principle at work?
@Steve Mosher: keep doing what you do. Your reality checks are needed, if only because it gives us all a shake and reminds us that things really aren’t quite as simple as “No, it doesn’t” or “No, it isn’t”. I’ve learned a lot from your comments, and I thank you for making them in spite of the vitriol that is so often directed your way. You seem to me to be an honest sceptic: one who questions the “consensus” but accepts what the evidence says, and isn’t afraid to say what he sees.
Respect.
I am more concerned with the lifeforms found on high with the dust, is it possible that this was the true transport of the 1918 flu pandemic.
Shall I impune the residents of the Sahara region, they are engaged in biological warfare, sarc off.
@ur momisugly Mosher, Are you competing for peak incoherence?
Search ‘Boedele Depression’.
The Heart of Dustness.
=================
Mosher’s problem is that if, in fact, man is responsible for the temperature rise since 1741, then where would we be without that rise? Colder, and colder to the extent that man is actually the cause of warming.
Furthermore, if the rise since the Little Ice Age is from Man, and not from the regular alternation of climate optima and minima in the Holocene, then we’re only escaping the onset of the next glaciation by our own efforts. The Little Ice Age was probably the coldest portion of the recent Holocene, and where do we go next?
There is a contradiction, nay, dilemma, in the attribution question.
=================
Seems like a lot of work. When I was a kid living on the south coast of England we would get red dust from the Sahara under the right conditions. Everybody knew about it then (1960s) so I guess it took just an extra 50 years for researchers to confirm what everyone knew – that dust can be transported a long way.
Hmmm. One can surmise from reading this study and comments that California’s Environmental Quality Act (CEQA) furthers less precipitation induced from atmospheric dust. How so? By mandating the Los Angeles Dept. of Water and Power to reduce dust clouds from the dry lake bed of Mono Lake, by reducing dust and soot from large scale construction projects, and from mandates to reduce agricultural dust from mass plowing.
In response to Steve Mosher’s mantra ““Next time you see or hear one of these arguments from a skeptic, correct them. Next time you hear the argument ” oh thats normal” understand: normal has nothing to do with understanding the cause of changes.” This is the opposite of the scientific method which is to question and disconfirm hypotheses.
If reduced atmospheric dust results in decreased precipitation then that will be used as proof positive of anthropogenic climate change. It may be anthropogenic but also enviro-genic.
There are unintended consequences and paradoxes involved in many environmental policies.
Beware the “certaintists” whether they be on the ideological Right of Left.
“Furthermore, the implications for future water resources become even more substantial when considering the possible increase in [wind-blown] dust as a result of a warming climate and land use changes”
Hum? Climate is not warming currently. (17 plus years) Worldwide drought is not increasing and planet is becoming greener.
Mosher does not understand skeptics. So Mosher, fyi, skeptics who do not accept CAGW are everyone else. They are from every other group, so do not cast them in one light.
They are not part of the herd, so stop placing them in a herd with your socialist instincts.
Steven Mosher said:
Next time you see or hear one of these arguments from a skeptic, correct them.
Next time you hear the argument ” oh thats normal” understand: normal has nothing to do with understanding the cause of changes.
This is why we need to understand the causes of earlier climate change.
Looking at the CET record for mean annual temperatures:
http://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat
analysis shows decadal rates of mean temperature change
1660 – 2009
y = 0.0026x + 4.5182 R2 = 0.393
Average 0.0026oC per decade
0.026oC per century
What are the cause of the decadal rate of change
1690 – 1739 (5 Decades – 50 years)
y = 0.038x – 56.056 R2 = 0.86
Average 0.038oC per decade
0.38oC per century
14.6 times overall rate
being faster than current rates of warming during the supposed period of anthropogenic effect?
1960 – 2009 (5 Decades – 50 years)
y = 0.0253x – 40.363 R2 = 0.74
Average 0.0253oC per decade
0.253oC per century
9.7 times overall rate
66.6% of 1690 – 1739 rate
1970 – 2009 (4 Decades – 40 years)
Y = 0.032x -54.204 R2 = 0.749
Average 0.032oC per decade
0.32oC per century
12.3 times overall rate
84.2% of 1690 – 1739 rate
Looking at periods of 30 and 60 years of CET mean temperatures – what are the causes of the trend over 30 years mean temperatures which reach a peak in 2007(1.51 oC per year) only matching the peak in 1720 (1.51 oC per year) or over 60 year trend peaking in 2009 (1.17oc per year) not reaching the peak of 1738 (1.55 oC per year)?
The idea that modelling of climate over a short data rich period can identify a step change in natural systems is seductive but leads to climate catastrophist thinking, with the present as the key to the future. Climate uniformitarians can see that the past is a good guide to the present and the future. The role of CO2 seems to play little part in temperature change over the measured record.
Philip Bradley says:
March 1, 2013 at 11:59 am
“Aerosols affect cloud formation and persistence, and common observation tells us clouds have a large effect on temperatures.”
Would it be accurate to say aerosols are a necessary requirement for cloud formation? Where would water vapour go if it could not condense onto the surface of an aerosol? How many droplets, aerosols with liquid water on them, go into making one raindrop?
I’m not sure the sign, warming or cooling, of aerosols is accounted for correctly;-
http://sitemaker.umich.edu/jasperkok/files/kok2011_pnas_scalingtheorydustpsd.pdf
Kok’s research indicates that the ratio of silt particles to clay particles is two to eight times greater than represented in climate models.
“Since climate scientists carefully calibrate the models to simulate the actual number of clay particles in the atmosphere, the paper suggests that models most likely err when it comes to the number of silt particles. Most of these larger particles swirl in the atmosphere within about 1,000 miles of desert regions, so adjusting their quantity in computer models should generate better projections of future climate in desert regions, such as the southwestern United States and northern Africa.”
http://www2.ucar.edu/atmosnews/news/3510/broken-glass-yields-clues-climate-change
So there is probably a lot more dark coloured, warming silt aerosols floating about. Also more aerosols in total so more ocean fertilisation and so more carbon uptake! Aerosols are a big ‘fudge factor’, make it up as you go along, uncertainty in the settled science of climate!
Josh,
I can assure you that Moshpit can write perfect English when he chooses to do so. I’m surprised that so few here seem to be aware of his background in, and positive contribution to, the climate wars. See
http://www.amazon.com/Climategate-Crutape-Letters-Steven-Mosher/dp/1450512437
A book I am proud to own.
He was an early and frequent commenter at Climate Audit. He did graduate work in Shakespeare, then moved into technology.
Well, duhhhhhhhhhhhhhh!
Steven Mosher says:
March 1, 2013 at 7:49 am
“Next time you hear the argument ” oh thats normal” understand: normal has nothing to do with understanding the cause of changes. So, you see those changes in California snow? normal. all normal. you canpoint back millsions of years and find less snow and more snow. But that observation tells you nothing about what causes the wiggles we see.”
You are suffering from a fundamental confusion. The more snow and less snow millions of years in the past establishes a minimum for nature’s variability. It gives us the crucial range of normal data. The point is data. Anything that falls within that range of data is normal for nature.
You want to replace the topic of natural variation, which is entirely about data, with the topic of causation. That is a typical Alarmist reflex. You cannot abide the idea of data that stands on its own without some theory to explain what caused it. That means that you can never recognize natural variation and you can never converse with skeptics about climate.
Natural variation is the range of our data. The range of our data does not have a cause. Natural variation is nature’s potential and it is not caused – unless you want to introduce a Deity and theological explanations of more snow and less snow.