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Northern Hemisphere Snow Cover


tacoman25

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I think 2000-2010 was their snowiest decade. It's trending upward due to a negative feedback caused by AGW. 

 

 

Not enough evidence for either argument thus far. Timescales are fairly short, seems to be a reoccurring problem when drawing conclusions in this field of study.

 

Then why did you claim the bolded as fact?

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How can you use historical analogs when the atmospheric content and associated interplay was different?

 

 

Establishing an internal source of variability helps us understand AGW's effects better. How do you think we know that a significant portion of the warming since the 19th century is attributable to AGW? We know because we measure the internal variability prior to AGW and conclude that the current rise is anomalously out of the typical internal ranges...we combine this knowledge with the physical radiating properties of GHGs and come to the conclusion that feedbacks are not negative and AGW is causing a majority of the warming.

 

 

For snow cover, we don't really know if AGW is affecting it in a net positive or negative way over Siberia in autumn. The changes are within the bounds of natural variability and we know that past periods of high and low snow cover have occurred. There's arguments that perhaps very recently (since 2007), the lower sea ice in autumn provides much more moisture in northern Siberia which increases the snow cover there...it's a compelling theory, but the sample is so low that it could also just be noise. If it was true, then AGW could be increasing it in the short term. But we don't know by how much because 1) the sample is too low 2) we still don't know how much AGW is responsible for the sea ice decline 3) Other factors such as the PDO and Asian monsoon patterns which could affect snow cover/moisture in Siberia.

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I know, right. The Eurasian side should be even more divergent in a few weeks. Talking major early season melt out.

The Pacific northwest only gets deep snow in the higher elevations and it gets mega deep.... the lower elevations don't really average much anyhow. One storm between now and April will change this situation. The lasting albedo from this cover is pretty short lived. If you want to look at Asia as being low, that's another story.

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The Pacific northwest only gets deep snow in the higher elevations and it gets mega deep.... the lower elevations don't really average much anyhow. One storm between now and April will change this situation. The lasting albedo from this cover is pretty short lived. If you want to look at Asia as being low, that's another story.

 

You are correct.  The Cascades can have over 20' of snow while the valleys and coastal regions have nothing. 

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Has been an unusual NHem. snow cover evolution this year with very rapid initial growth and then a stall since the end of November, Could lead to a fast spring warm-up in some areas

nhemsnow.png

Most western US snowcover outside of the mountains averaged around 3-10 inches deep last year at this time. Two sunny days above 40F and it would have melted regardless. So the cooling effect would have been short lived.

Actually that map probably changed a lot since you posted it for last year, most of the western US has no snow outside the mountains. The snowcover lasted just a day or two after a torch. Just as I assumed.

post-7333-0-27135300-1423880374_thumb.pn

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Easy to see why harmonics are so important and how fast things can run in the other direction.

To elaborate a bit more. I think we underestimate how much albedo can affect cloud cover and fog generation. Albedo reduction constitutes a key feedback to global warming, especially before ECS is fully realized.

 

We've never really observed a snow-starved February yet, and as a result the month was running colder on most datasets in recent years. In my mind, this signals a significant shift in the climate system and could be a major impetus for other processes going forward.

 

February GISS temperatures

 

2008  31 

2009  48 

2010  74 

2011  44

2012  43 

2013  51 

2014  43 

(2015) 76-88

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To elaborate a bit more. I think we underestimate how much albedo can affect cloud cover and fog generation. Albedo reduction constitutes a key feedback to global warming, especially before ECS is fully realized.

 

We've never really observed a snow-starved February yet, and as a result the month was running colder on most datasets in recent years. In my mind, this signals a significant shift in the climate system and could be a major impetus for other processes going forward.

 

February GISS temperatures

 

2008  31 

2009  48 

2010  74 

2011  44

2012  43 

2013  51 

2014  43 

(2015) 76-88

 

It's like 5% lower than the mean or less.... It's not even the lowest on record.

 

February 1998 was 86. That's unlikely, but in play.

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