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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There had to be a ‘blame it on humans’ reason for this study. Funny though, I would have thought that a cooler climate would mean less airborne moisture over the Sahara, less rain, and therefor it would be easier to create dust storms.
as expected, the manadatory blame statement in order to get funding:
“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”
This is more like serious research that is credible. So yes emissions may affect weather /climate. I don’t think we skeptics [snip] would have a problem with this. Let us remember that it is the CO2/warming story that is not credible. Maybe the warmistas and C02 skeptics [snip] will have now a commonality as long as the AGW crowd are prepared to surrender the CO2 fantasy. LOL
None of their computer simulations are credible!!! not one.
Eliza:
‘This is more like serious research that is credible. So yes emissions may affect weather /climate. I don’t think we skeptics [snip] would have a problem with this. ”
You will find many skeptics areguing that man cannot effect climate in any way. That climate is too complex, that the changes folks see in snow are “normal” etc etc.
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.
This sounds to me like a bureaucrats dream. I can see our new distinguished Secretary of State trying to balance the EPA limitations of sulfur emissions and dust from farms with Asian complaints to the UN that we are attempting to destabilize their economies by affecting their rainfall. With a little bit of luck we can get a new UN study group looking at how plowing of fields in west Texas should be regulated.
I truly wish that I possessed a wit and a vocabulary that would have enabled me to stand any chance of getting my first reaction past the moderator.
“Gas and ashes have risen almost 2.5 miles (4km) into the sky during the ongoing eruption of a volcano on the Kamchatka Peninsula in Russia.”
http://www.bbc.co.uk/news/world-europe-20998967
“Experts say the Plosky Tolbachik volcano could continue to erupt for four months, as Mike Embley explains”
More dust
Steven Mosher says:
March 1, 2013 at 7:49 am
You will find many skeptics areguing that man cannot effect climate in any way.
—-
You are seeing what you want to see.
While there are a few who make this arguement it takes a willfull suspension of disbelief to inflate this number to “many”.
Steven Mosher says:
March 1, 2013 at 7:49 am
…….. 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.
That is an incorrect statement Steven. What it says “about the cause of warming from 1750 to today.” is that it could be completely normal internal variation in the chaotic climate system of chaotic systems. What has yet to be proven is that there is anything ‘out of the ordinary’ in the warming from 1750 to 1997. It would appear that there have been many such warming episodes in the past that predated the presence of human’s “to blame” for the warming.
The presence of warming itself is not proof of the causality being anthropogenic. So if the intent is to blame human activities for the 20th century warming, and then to claim catastrophe if that warming continues; and put in place mitigations to the extent of strangling economies; there is a burden of proof. That proof needs to be empirical proof showing that the human emissions or activities are causing dangerous warming. So far every metric hypothesized has been falsified and the models on which the catastrophic warnings were based have all been shown to be wildly inaccurate. The repeated moving of the goal posts on these catastrophic metric indicators such as no-snow/more-snow – continual-droughts/continual-floods warming-meaning-colder; does not increase the level of belief in the veracity of climate ‘scientists’.
There is now a mountain of travesties to climb a little discipline in the varied projections of doom would not go amiss, followed by solid empirical validation.
@ur momisugly Mosher, given the level of knowledge about meteorological events and their genesis that you have exhibited recently, your advice sounds quite hollow.
Steve Mosher says..
“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”
It is absurd to blame that warming on CO2 from humans for the first 200 years or so of that. Thus ‘normal’ includes some very powerful forces. Did these powerful forces go into hibernatiion in the past 70 years or so, such that humans are to blame for the recent warming? I doubt it, thus I am a CAGW skeptic.
(btw, I like the warming.. keep it coming please, and my favorite plant, sweetcorn, likes the CO2, so keep it coming!)
The theory holds water.
Although it is interesting to note that other research has suggested the opposite, so one of them is wrong. But as mentioned it is not yet clear which particles and other influences cause more and which less rain, sitting on the fence with a bob each way. And the ever present caveat that more research is needed.
Our species got out of the woods and needed to walk upright to cover bigger distances due to a cooling climate with less rainfall creating the fast open savannah and less easy to obtain food. While it may be just coincidence that every time the climate cools there is less precipitation the opposite also seems to have been the case
Extreme weather would also appear to be decreasing in a warming world if evidence from the MWP and RWP is anything to go by.
Not sure though if the minimal increase, now leveled off, in temp we were seeing is enough to really influence either, or for that matter if that slight increase is not due to (manmade) adjustments and/or different (better one would hope) measuring equipment.
One thing seems sure, if we soon want to feed 9 billion of us we need more rain and more CO2.
Ed_B says:
March 1, 2013 at 7:27 am
I don’t find anything at all sinister about this story. It sounds like good scientists doing good science. If you feel a desperate need to put a climate change spin on it, you could say that the story is good for skeptics because warming will increase precipitation in drought-prone California.
Forgot to mention as addition to the last sentence:
plus a reliable energy supply.
With the emphasis on reliable.
Unfortunately, even credible science these days is infected with a CAGW bias, which is then incorporated into almost all climate related grant proposal in an effort to improve the probability of receiving funding.
Subsequently, when the data is analyzed and conclusions are drawn, scientists are obliged to make some boiler-plate reference to an anthropogenic effect, even if the empirical data showing such a relation doesn’t actually exist and is merely conjectured out of formality.
This paper states, “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.”
This statement begs the question, what warming? There hasn’t been any statistically significant “warming” since August 1997….
So, while there may well be a causal relationship between aerosol particulates and precipitation, the inference that this is related to CAGW is up an unsubstantiated assumption.
It’s depressing to see science becoming so jaded by CAGW.
Do you have any information on the
“cause of warming from 1750 to today.”?
as well as the
“cause of warming from 1750 to” 1960?
[my bold]
Thanks in advance.
I certainly don’t think that. Here’s a bit of advice: next time wait until 30 or so comments down, look for those who argue “that man cannot effect climate in any way” then comment. You are almost trying to put words into people’s mouths. In fact you have been doing a lot of accusing of sceptics lately. Keep a lid on it until you find people saying what you think they are going to say.
@Ed_B says:
March 1, 2013 at 7:27 am
The article says “warming climate”, not “man-made warming climate”. Don’t read more into it than is acutally present.
Do the activities of man contribute to climate changes here on Earth? Yes. It is obvious that our civilized society changes the climate in many ways from stirring the dust in the air to the urban heat islands to the contrails of jet aircraft to producing particulate matter and increasing the CO2 in the atmosphere by our use of fossil fuels. However, I am firmly convienced that none of these effects is highly signficiant and going to have any catastrophic effect on climate. Should we work to clean the air and water and reduce our influences on climate. Yes. Should we panic and label CO2 as polutant and cripple our society via an anti fossil fuel, anti CO2 campaign. Absolutely not. There is no scientifically valid justification for this highly destructive policy. I support Scripps Oceanagraphic Institute (here in my hometown of San Diego) when it does good, even great, science. I oppose their anti fossil fuel, CO2 forcing, catatrophic AGW campaign with everything I’ve got. We should all work together to reduce mankind’s impact on climate, but we should do it without “the sky in falling” silliness. Once the global warming team turns lose of its anti CO2 extremism, I look foward to working together to reduce the impact of our civilization on the air and water and climate.
Steven Mosher says:
March 1, 2013 at 7:49 am
“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.”
Steven, What an incredibly simplistic answer. Just because dust reaches the Sierra Nevada range and may affect the amount of snow to some extent is a long way from the statement that “man has significant impacts on California snow packs”. The dominant mechanism for high snow pack years vs low snow pack years is the storm track. This has been understood for decades.
What AGW activists need to show in all areas is that man’s impact on climate is important – not just that it exists. As long as natural variations are much, much bigger than any impact by man – the answer natural variations is the appropriate one.
Steven Mosher says:
March 1, 2013 at 7:49 am
But that observation says nothing about the cause of warming from 1750 to today.
===================================
good grief Elizabeth
http://wattsupwiththat.com/2009/12/09/hockey-stick-observed-in-noaa-ice-core-data/
I don’t have any personal experience of sand/dust going that far, but Sahara sand frequently finds its way to the UK (to the South, anyway). When we lived in Kent – the far SE – we often found obvious signs of yellow sand from the Sahara on our car and the windows of our house, and now in Devon it still happens though it appears to be less frequent here.
Speaking of sand storms, it looks like Beijing is having a rather large one. http://news.yahoo.com/photos/sandstorm-hits-china-slideshow/
As the sand is rather low it is unlikely going to make it the foothills of the Sierra. Although if some of the sand/dust etc made it overhear it would be Ok with me as we haven’t had much rain in the last two months.
Here are some dust posts from WUWT. Many sceptics actually argue that dust can affect the climate.
I think John Coleman above has the spot on correct idea. Human C02 has got nothing whatsoever to do with increasing or decreasing global temperatures. The urban island effect on temperatures recorded in cities airports is a good example of “human” effect but it has no bearing whatsoever on mean satellite global temperatures.(To be corrected if I am wrong here). All ice extent and volume indices are currently normal See DMI and CT today), so are global temperatures compared to 1979 ect (see Latest from AMSU). The AGW “theory” is being keep alive through manipulation of data and stories of extremes which cannot continue to be manipulated further due to backtracking facilities on the internet (refer to Steven Goddards site Real Science),. and fear of prosecution (have a look at Jo Anne site re Monckton). The rats are running for cover everywhere. See Germany where only Ramsdorf is left believing in this AGW tripe. As Prof Singer says It will take 10 years for it to be over. I would not like to be one of the current AGW climate scientist still pushing the fraud now, in 10 years time.
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.
If soot and other pollution is required to form into clouds, can we then blame the EPA 2.5m pollution limits for causing the recent droughts?