From NASA Goddard: Tiny particles suspended in the air, known as aerosols, can darken snow and ice causing it to absorb more of the sun’s energy. But until recently, scientists rarely considered the effect of all three major types of light-absorbing aerosols together in climate models.
In a new study, NASA scientists used a climate model to examine the impact of this snow-darkening phenomenon on Northern Hemisphere snowpacks, including how it affects snow amount and heating on the ground in spring.
The study looked at three types of light-absorbing aerosols – dust, black carbon and organic carbon. Black carbon and organic carbon are produced from the burning of fossil fuels, like coal and oil, as well as biofuels and biomass, such as forests.
With their snow darkening effect added to NASA’s GEOS-5 climate model, scientists analyzed results from 2002 to 2011, and compared them to model runs done without the aerosols on snow. They found that the aerosols indeed played a role in absorbing more of the sun’s energy. Over broad places in the Northern Hemisphere, the darkened snow caused some surface temperatures to be up to 10 degrees Fahrenheit warmer than it would be if the snow were pristine. As a result, warmer, snow-darkened areas had less snow in spring than they would have had under pristine snow conditions.
According to the study, dust’s snow darkening effect significantly contributed to surface warming in Central Asia and the western Himalayas. Black carbon’s snow darkening effect had a larger impact primarily in Europe, the eastern Himalayas and East Asia. It had a smaller impact in North America. Organic carbon’s snow darkening effect was relatively lower but present in regions such as southeastern Siberia, northeastern East Asia and western Canada.
“As we add more of these aerosols to the mix, we are potentially increasing our overall impact on Earth’s climate,” said research scientist Teppei Yasunari at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.Impact of snow darkening via dust, black carbon, and organic carbon on boreal spring climate in the Earth system, Journal: Geophysical Research: Atmospheres.
http://onlinelibrary.wiley.com/doi/10.1002/2014JD022977/full
Abstract
Dust, black carbon (BC), and organic carbon (OC) aerosols, when deposited onto snow, are known to reduce the albedo of the snow (i.e., snow darkening effect (SDE)). Here using the NASA Goddard Earth Observing System Model, Version 5 (GEOS-5) with aerosol tracers and a state-of-the-art snow darkening module (GOddard SnoW Impurity Module: GOSWIM) for the land surface, we examine the role of SDE on climate in the boreal spring snowmelt season. SDE is found to produce significant surface warming (over 15 W m−2) over broad areas in midlatitudes, with dust being the most important contributor to the warming in central Asia and the western Himalayas and with BC having larger impact in the Europe, eastern Himalayas, East Asia, and North America. The contribution of OC to the warming is generally low but still significant mainly over southeastern Siberia, northeastern East Asia, and western Canada (~19% of the total solar visible absorption by these snow impurities). The simulations suggest that SDE strengthens the boreal spring water cycle in East Asia through water recycling and moisture advection from the ocean and contributes to the maintenance of dry conditions in parts of a region spanning Europe to central Asia, partially through feedback on the model’s background climatology. Overall, our study suggests that the existence of SDE in the Earth system associated with dust, BC, and OC contributes significantly to enhanced surface warming over continents in northern hemisphere midlatitudes during boreal spring, raising the surface skin temperature by approximately 3–6 K near the snowline.
h/t to WUWT reader “Parakoch”
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“From NASA Goddard: Tiny particles suspended in the air, known as aerosols, can darken snow and ice causing it to absorb more of the sun’s energy. ”
1) Then does that [mean] soot and not global warming has been melting the glaciers?
2) My bet is that soot partially cooled the globe prior to 1970’s Clean Air Act, and that is why the N Hemi temperature has a rapid increase after 1970, and then temperatures plateau with China’s growth starting in about 1995.
Can somebody explain why a pile of snow removed from a parking lot and dumped in a heap does not disappear until way after snow has gone ( as in weeks). i realize there is a density thing involved but the article talks about sea ice and soot The snow pile seems to smaller but has a thick layer of dirt etc on it as it melts but contrary to what is being said it lasts a lot longer than the regular snow layers witch also has a layer of soot on it btw.
It has to do with the thickness of the soot and dirt layer. It can also form a protective shell, protecting the snow and ice from the heat. It acts like an insulator.
But hey, if Australia deindustrialises that should make a huge difference.
Yes, snow and ice can melt when the ambient temperature is below freezing. I have been spreading the ash from my pellet stoves over the snow and it melts like July, except in February.
Except for the fact that your trick doesn’t work after 9:00 pm and before 4:00 am
More like from 5PM to 7AM…
I tried to make a “safe” guess, not knowing exactly what latitude you reside at.
From NASA Goddard: Tiny particles suspended in the air, known as aerosols, can darken snow and ice causing it to absorb more of the sun’s energy. But until recently, scientists rarely considered the effect of all three major types of light-absorbing aerosols together in climate models.
Is this a joke?
Leading up to the 2009 Copenhagen Climate Conference, we were told the IPCC’s 2007 4th Assessment Report was the “gold standard in climate science”. Global warming alarmists, from Al Gore to UK Prime Minister Gordon Brown, proclaimed “the science is settled”.
What say those global warming alarmists, today, who declared “the science is settled”? All the scientific revelations since 2009 have demonstrated the science was never settled, and the IPCC Chairman, Dr Pachouri, really got it so very wrong.
Presumably during the epoch of snowball earth when most incoming radiation was reflected,, the cycle was broken by volcanic action, blackening the surface thereby increasing the absorptivity/emissivity
chemengrls “Presumably during the epoch of snowball earth when most incoming radiation was reflected,, the cycle was broken by volcanic action, blackening the surface thereby increasing the absorptivity/emissivity”
Ice has a near unity emissivity. At long infrared wavelengths, ice is “black”. It is reflective to visible wavelengths.
What seems to be believed about the Earth’s escape from snowball state was an enormous concentration of carbon dioxide, about 100,000 ppm accumulating over several million years since no plant life-cycle existed to take up the carbon dioxide. That produced a greenhouse effect powerful enough to overcome the reflectivity of the ice. What happened next I do not know but I suspect that much carbon in the atmosphere produced an incredible surge in carbon-loving plant life and subsequent oxygenation of the atmosphere along with huge beds of carbonate rock being laid down in the seas.
Increasing the emissivity raising the temp and thereby melting the ice.