How is the Volume Pulse going?

Earlier this month I didn't have the time to look at January's PIOMAS data, and still don't really aim to cover PIOMAS in detail until April's data is out in early May. At that stage I will make my prediction for this year's SIPN. However I have been looking at how the volume pulse is going and thought I'd do a quick update on it.

Why is extent so low?

This post looks at why Northern Hemisphere (NH) sea ice extent is so low at present. A commenter Dreesen asked what I thought about it, and due to work pressures I hadn't looked at sea ice for weeks. The low sea ice is likely due to a combination of long term reduction due to global warming and weather in the North Atlantic. But temperatures in January were extreme, and I lack a convincing answer as to why.

(This post was largely written on Sunday but I've been too busy to do a final check and post until now.)

May 2015 Status: Four Dipoles

Not all of the NCEP/NCAR data is available, and PIOMAS is yet to be released, but with the data available there is still a lot to cover about sea ice state in May 2015.

March 2015 Status

Data is now in for March 2015, the early maximum is confirmed, temperatures over autumn/winter continue the pattern of recent years, and the volume increase in PIOMAS remains. This year takes volume back to 2010 levels, but the impact of 2007 remains clear. My entry for the 2015 Sea Ice Prediction Network (SIPN) is given at the end of this post.

Where is the ice in the Bering Sea?

Like me, you've probably noticed the singular lack of ice in the Bering Sea, it is very unusual and the cause is northward air flow. That's as good an excuse as any for my first blog post of the 2015 sea ice year.

There are Monsters in the Ocean.

Today a large storm has been battering the north of the UK, I've been stuck at work, but I just couldn't stop myself checking up on one buoy in particular.

Mid November Status

Rather than just do a PIOMAS post, this post presents a few reflections on ice state in October as the refreeze progresses using various sources.

PIOMAS February 2014

In terms of PIOMAS total volume the winter sea ice seems to have lost the 2013 volume gain. What might this mean for 2014's impending melt season?

UK Floods In Context

I am tempted to make some cutting comment about those who indulge in games of 'look squirrel' and those who publicise them, but such people bore me.

There are times when only a simple graph is needed.

Data from here.

UK Summer Rainfall - Some notes on the Jetstream.

I've been digging a bit more into record UK rainfall, not a major revelation, but I thought it worth blogging as this blog is essentially my on-line notebook. I don't intend to blog on summer rainfall in the UK again until I've seen what this summer brings.

UK Wet Summers post 2007: How Unusual?

In my mid month miscellanea post earlier today I posted a list of the top ten wettest summers, four of those are years from 2007 to 2013. Just how odd is this?

The Atmosphere Goes Bonkers!

For my first post of the new year I can only start looking at the atmosphere, despite PIOMAS gridded data being out. I have to start here because the atmosphere is going nuts. Here in the UK we've been hammered by a succession of storms from an Atlantic synoptic pattern that keeps defaulting to basin wide monster low pressures. Now over in the States there's a monster of an Arctic Breakout.

European Precipitation and Sea Ice Loss

James Screen has released a lot of important papers on Arctic sea ice loss and the atmosphere, he's done it again, in "Influence of Arctic sea ice on European summer precipitation.", not paywalled.

I'm particularly excited about this because it goes some way to supporting something I've been going on about for two years now. I should point out at the outset - it is very unlikely that Dr Screen is aware of my persistent blogging on this subject!

Winter warming and sea ice thinning.

Arctic Amplification is the tendency of the Arctic region to warm more than the global average with Global Warming. While it is an effect initially seen in modelling studies it has been recently found to be emerging from natural variability. I have used PIOMAS gridded sea ice thickness data and NCEP/NCAR atmospheric temperature data to examine the connection between sea ice thinning and winter warming.

Siberian and Greenland geopotential height anomalies

Early last year I wrote a post on Eurasian snow cover, link, I've revisited this as part of my continuing attempt to explain the Greenland centred summer pattern.

Francis/Vavrus and the slower jetstream.

I've previously mentioned the Francis/Vavrus paper linking mid latitude persistent weather to Arctic Amplification, copy here, but haven't properly blogged on it. However I have drawn the paper in as a possible factor in the behaviour of blocking activity in a previous post. But the conclusions drawn there are not central to that post, merely an aside.

I say this because I'm pretty sure that the Francis/Vavrus paper is wrong in doubt. EDIT - amended in light of reading Dr Francis's response in the WP - see comments. 

July Status Part 2: Atmosphere

NCEP/NCAR Reanalysis data for July is now available, so it is possible to assess what the atmospheric state has been in July, and for the summer so far. The atmospheric state in 2013 continues to be remarkable in the context of the other post 2007 years, and this is clearly the proximate cause of the slow melt season seen in 2013.

July Status Part 1: Cryosphere Today Area

The full data for June are now available for Cryosphere Today Area (CT Area). As usual I'm still waiting for NCEP/NCAR reanalysis to produce July average, and as PIOMAS uses NCEP/NCAR data they don't publish their main series on the first of the month. So I'll start by going over CT Area, atmosphere and volume will follow in the next few days.

June Status Part 2b - Atmosphere and Ice.

In my previous post I produced a series of sea level pressure (SLP) plots from NCEP/NCAR reanalysis showing how anomalous the SLP field for 2013 is in the context of the other post 2007 years, link. As stated previously, looking at Cryosphere Today Area (CT Area) on 30 June one has to go back to 2009 for a single year above 30 June 2013, and back to 2004 to find successive preceding years of higher area for that date. Given the loss of volume in 2010*, and that this was followed by a new record in the CT Area data for 2011, 2012 then setting a new record by a substantial margin, the late start to the melt season in spring 2013 is highly anomalous. *Whilst this was an event first noticed in PIOMAS it was a real event in the real world, and not just an event within the PIOMAS model, link.

The Causes of Arctic Amplification.

Arctic Amplification is the term used for the enhanced warming of the Arctic when compared to warming rates for the rest of the globe. While the changes in the Arctic are driven by human activities, as discussed previously, human activities have proven little more than a 'prompting' for a region whose dynamics are driven by powerful feedbacks.

The Arctic is warming, but the pattern of warming over the year, and between surface and aloft is complex, what is causing this warming? In 2012 Screen et al published "Local and remote forcing of observed Arctic warming", PDF in which they used a series of reanalysis data sets and the results of experiments in two climate models to examine the causes of Arctic Amplification.