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Japan Meteorological Agency — September of 2015 was Hottest on Record — NASA not Far Behind
With
a monster El Nino firing off in the Pacific and
with atmospheric
greenhouse gas concentrations now in excess of 480 parts per millions
CO2 equivalent,
global temperatures for 2015 continue to shatter new all-time
records. It’s a sad upshot of continued energy dominance by myopic
fossil fuel special interests and the big money investors who have
backed them now for the better part of 135 years.
As
of September of 2015, temperatures in the global measure provided
by Japan’s
Meteorological Agency rocketed
to 0.5 C above the 1981 to 2000 average or about 1.2 C above average
temperatures last seen at the beginning of the 20th Century.
(Japan’s
Meteorological Agency shows that global temperatures sky-rocketed to
a new record in September. Image source: JMA.)
This
departure is a whopping 0.4 C above baseline rates of increase and a
significant 0.15 C above the old record high for September set just
last year (2014). Perhaps more notable is that all
of the five hottest Septembers have occurred since 2009.
A very strong global warming signal for the month and one that has
left the 1997-1998 El Nino years in the dust.
NASA
Shows September of 2015 was Second Hottest on Record
Though
NOAA has yet to chime in with
its monthly global temperature and climate analysis,
NASA’s own GISS
temperature monitor also
shows September hitting near record heat. According to NASA,
September of 2015 came in 0.81 C hotter than its own 20th Century
benchmark average and about 1.01 C hotter than 1880s averages. This
puts September of 2015 as a solid 2nd hottest in NASA’s
record and
just behind the new record set for September just last year.
NASA’s
measure shows that four of the five hottest Septembers have all
occurred since 2012 (ranking
2014 first hottest at +0.90 C, 2015 second hottest at +0.81 C, 2013
tied for third hottest with 2005 at +0.77 C, and 2012 as fourth
hottest at +0.75 C). 2015’s +0.81 C departure is also well in
excess of the +0.56 C departure seen in 1997 during the ramp up of
what was then the strongest El Nino on record with averages for
Septembers of 2014 and 2015 now at about +0.30 C above 1997 levels. A
jump that falls neatly in the range of temperature increases
predicted by IPCC and following the +0.15 to +0.20 C per decade
accelerated rate of increase seen globally since around 1980.
Despite
Strong El Nino, Northern Hemisphere Polar Amplification Really Heats
up in September
NASA’s
geographic distribution of temperature anomalies map tells a rather
interesting tale for September. One that may have implications for
Northern Hemisphere weather further down the line as Fall and Winter
progress.
(NASA’s
global temperature anomalies map shows strong warming at both the
Equator and the Northern Hemisphere Pole during September. A
signature that hints strong south to north heat transfers are at
play. Image source: NASA
GISS.)
As
expected with a strong El Nino, we see a lot of heat building up
along the Equatorial zone and especially in the Eastern Pacific where
land-ocean temperatures hit a strong range of +2 to +4 C above
average. A bit odd, however, is a strong heat plume visibly rising
off this hot zone, traversing the western land mass of North America
and entering the Arctic through the gateway of the Canadian
Archipelago (CAA). Notably, high Arctic temperature anomalies in the
zone north of the CAA also spike to levels in the range of +2 to +4 C
above average. It’s a kind of south to north heat transfer that we
would expect to see less and less of as El Nino strengthens and the
storm track flattens out. But ridging over the North American West
along with associated heat continued to remain in force throughout
September providing a pathway for heat to enter the upper Latitudes.
Other
strong, though somewhat less robust, Equator to Pole heat transfers
appear visible over Europe on up through Scandinavia, and ranging
along a diagonal between India, China, Mongolia and Kamchatka. It’s
a heat signature picture of a mangled Jet Stream completed by trough
zones and cool pools over Alaska, in the ominous region of the North
Atlantic between Greenland and England, in Central Asia, and just
east of Japan. Most notably, the cool pool associated with a
weakening Atlantic Meridional Overturning Circulation (AMOC) and
all-too-likely due to the decadally increasing rates of glacial melt
outflows from Greenland remains a dominant feature in the North
Atlantic. It’s a cool pool signature that was predicted in almost
all the global climate models in association with overall human
forced warming of the atmosphere and ocean. One that can drive
weather instability in the North Atlantic. And one that has been a
nearly constant features since at least 2012.
NASA’s
zonal anomalies map paints a picture of both Equatorial and Northern
Hemisphere Polar heat with temperatures well above average over most
regions of the world. The primary exception is Antarctica and the
Southern Ocean which, during recent years, has acted as an
atmosphere-to-ocean heat sink. Notably, a very strong storm track in
the region of 50 South Latitude has driven powerful winds which have
forced atmospheric heat into the ocean depths while also forming an
atmospheric barrier to heat conveyance over Antarctica.
High
Latitude regions between 85 and 90 North showed the most extreme
temperature departures with a +1.6 C positive anomaly for the region.
Temperatures drop somewhat to between +1 and +1.3 C from 30 to 70
North before rising again to around +1.4 C near the Equator.
Anomalies drop off southward ranging from near +0.7 C around 30 South
before dropping into negative values in the atmosphere to ocean heat
uptake zone in the Southern Ocean near 60 South.
Winter
Weather for 2015 May Feature Some Unexpected Twists
Overall
dispersal of heat shows a notably high degree of Northern Hemisphere
polar amplification at a time when El Nino should be spiking heat at
the Equator, increasing Jet Stream strength, and pushing the Northern
Hemisphere Polar zone to cool somewhat. The fact that the Pole
remained at higher positive temperature anomalies than the Equator
during September even as El Nino cracked +2 C above average heat in
the Nino 3.4 zone hints that this Winter may show more waviness in
the Jet Stream than is typical during a strong El Nino year. As a
result, weather patterns typical to El Nino during Northern
Hemisphere Winter may show marked variance.
If
this is the case, rainfall amounts for Southern and Central
California may be less than expected for a typical strong El Nino
year. Heavy rainfall events may shift northward toward Oregon,
Washington, British Columbia and Alaska. A northward angling storm
track over Western North America would tend to reinforce trough
development in the east while providing major storms for the US East
Coast and Northeast as the higher amplitude Jet Stream wave taps more
Arctic air than is typical. Meanwhile, warm waters off the US East
Coast in the range of +2 to +5 C above average will provide both heat
and moisture as fuel for storms moving down any trough feature. Extra
heat and moisture provided by El Nino will also tend to
preferentially increase storm intensity all along the storm track
even as temperature differentials at the sea surface in the North
Atlantic provide further instability for storms that are likely to
hit high intensity along a track between Iceland and the United
Kingdom. Meanwhile, these features, combined with warmer than normal
sea surface temperatures in the newly ice-liberated Barents, could
result in warmer and stormier conditions for Northern Europe and
Scandinavia.
Globally,
we are likely in for a record hot Northern Hemisphere winter for
2015. Combined with one of the strongest El Ninos on record, such a
high temperature excession may well put us into a number of entirely
new, and potentially very stormy, weather contexts. Comprehensive
monitoring and updates to follow.
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