Friday, January 19, 2018

Graphs of 2017 global temperatures among record years for major indices

A few days ago, I posted some graphs in an updated style which shows 2017, as seen by TempLS mesh in its place among records years (2017 came second) in a progressive record style. I also showed a detailed graph of the sequence of months from 2014 to 2017, showing how the warming introduced by the El Niño seems to be lasting. I said I would do a similar set of plots for the major indices when they appeared, as I have done in previous years. By now NOAA, HADCRUT and GISS have reported, as well as the satellite indices. So here is the set of progressive record plots. We have so far:
  • GISSlo - Gistemp land/ocean
  • HADCRUT 4 land/ocean
  • NOAAlo - NOAA land/ocean
  • UAH V6.0 - lower troposphere (TLT satellite)
  • RSS V4.0 - lower troposphere (TLT satellite)
  • CRUTEM 4 - land only
  • TempLS mesh
I'll add more as they arrive. You can find more information about the indices, with source links, here. The Glossary may help too. You can flick through the 7 images using the buttons below the plot.

GISS and TempLS had 2017 in second place, as did RSS V4.0. HADCRUT, CRUTEM and NOAAlo put it behind 2015 in third place. UAH V6 had things in a very different order, with 1988 in second place, and 2017 a distant third. The grouping of the surface indices is commonly observed. TempLS mesh and GISS interpolate, giving more (and IMO cdue) weight to polar regions. NOAA and HADCRUT do so much less. So insofar as the warmth of 2017 was accentuated at the poles, the less interpolated indices tend to miss that.

Here is the set of monthly averages for each of those indices, with as before the annual averages shown as horizontal lines in the appropriate color. Almost all months of 2017 were well above the 2014 average, even though 2014 was a record year in its time.






GISS December global up 0.02°C; 2017 was second warmest.

GISS warmed slightly, going from 0.87°C in November to 0.89°C in December (GISS report here). That is very similar to TempLS mesh; I originally reported no change, but later data pushed that up to a 0.04°C rise. For GISS, that makes 2017 the second warmest year in their record; behind 2016 but ahead of 2015. Their report, with the annual summary too, is here. I showed some aspects of 2017 annual in context here, and I'll do that for GISS and other indices in an upcoming post.

The overall pattern was similar to that in TempLS. Cold in east N America and Mediterranean and far East Siberia. Very warm in most of Russia, and in the Arctic. A cool La Nina-ish plume, but warm in the Tasman sea.

As usual here, I will compare the GISS and previous TempLS plots below the jump.

Wednesday, January 10, 2018

Review of 2017, heat records, and recent warm years.

Yesterday I posted the December global anomaly (base 1961-90) results for TempLS mesh, and noted that it made 2017 the second warmest year, after 2016. I'd like to put that in a bit more context. For the last three years (eg here) I have posted a progressive plot showing in steps the advance of the hottest year to date. Since 2014, 2015 and 2016 were each the hottest years to date, there was something new to show each year, and the plot showed the rapidity of those rises. This year, with 2017 in second place, it doesn't add new information to that style of plot. So I tried a way of adding information. I superimposed on the steps plot a column plot of each year's temperature. This measn that you can follow the max outline, or focus on the columns, which also show how far the years following a record were cooler. It emphasises the warmth of 2017 relative to earlier years. Here is the plot:



The legend shows the color codes for the record years. I'll probably make an active plot of all the indices when they become available. But I was also curious about how 2017 came to be warmer than the near Niño year of 2015. So I drew a column plot by month of the last four years, shown by color
I've also marked each year's average in the appropriate colour. 2017 is almost a mirror image of 2015, and the main contribution to its warmth came from the first three months, a somewhat separate peak from the El Niño. But what is clear is that the apparent level of later 2016 and 2017 is a good deal higher than 2014, a record year in its day. Even the coolest month of 2016/7 (June 17) was at about the 2014 average.

In my previous post, I reported December 2017 as virtually unchanged from November. Further data has made it a little warmer. In other news, the Australia BoM 2017 climate statement is out, and here 2017 was the third warmest year, after 2013 and 2005.


Tuesday, January 9, 2018

December global surface temperature unchanged; 2017 was second warmest year.

TempLS mesh anomaly (1961-90 base) was virtually unchanged, from 0.716°C in November to 0.721°C in December. This compares with the rise of 0.075°C in the NCEP/NCAR index, and a similar rise (0.05) in the UAH LT satellite index.

The TempLS average for 2017 was thus 0.757°C, which puts it behind 2016 (0.836°C), and ahead of 2015 (0.729°C), and so was the second warmest year in the record. I expect this will be a common finding, although 2015 is close. I'll post a graph showing the history of records.

The breakdown is interesting. The main cooling effect came from SST, well down on November. The balancing rises came from the Arctic and Siberia. Since TempLS, like GISS, is sensitive to Arctic temperature, indices like NOAA/HADCRUT may well show a fall. Otherwise the map shows those effects, along with much-discussed cold around the Great Lakes region and also W Sahara.

Here is the temperature map:


Thursday, January 4, 2018

December NCEP/NCAR global anomaly up 0.075°C from November

In the Moyhu NCEP/NCAR index, the monthly reanalysis anomaly average rose from 0.253°C in November to 0.328°C in December, 2017, making it a mid-range month for 2017. The temperature did not oscillate as much as in some recent months.

The main cool spots were Canada and E Siberia, NW Africa (Algeria) and Antarctica. East Europe and NW Russia were warm, and also Alaska and a band through the Rockies, S Calif. There was a notable warm spot in the seas around New Zealand.

The annual averfage for 2017 was 0.376°C. This puts it behind 2016 (0.531) but ahead of 2015 (0.330) and 2014 (0.190).