Thursday, August 17, 2017

Temperature averaging and integration - the basics

I write a lot about spatial integration, which is at the heart of global temperature averaging. I'll write more here about the principles involved. But I'm also writing to place in context methods I use in TempLS, which I think are an advance on what is currently usual. I last wrote a comparison of methods in 2015 here, which I plan to update in a sequel. Some issues here arose in a discussion at Climate Audit.

It's a long post, so I'll include a table of contents. I want to start from first principles and make some math connections. I'll use paler colors for the bits that are more mathy or that are just to make the logic connect, but which could be skipped.

Wednesday, August 16, 2017

GISS July up 0.15°C from June.

GISS was up from 0.68°C in June to 0.83°C in July. It was the warmest July in the record, though the GISS report says it "statistically tied" with 2016 (0.82). The increase was similar to the 0.12°C rise in TempLS.

The overall pattern was similar to that in TempLS. Warm almost everywhere, with a big band across mid-latitude Eurasia and N Africa. Cool in parts of the Arctic, which may save some ice.

I'll show the plot of recent months on the same 1981-2010 base, mainly because they are currently unusually unanimous. The group HADCRUT/NOAA/TempLS_grid tend to be less sensitive to the Antarctic variations that have dominated recent months, and I'd expect them to be not much changed in July also, which would leave them also in much the same place.



Recently, August reanalysis has been unusually warm. As usual here, I will compare the GISS and previous TempLS plots below the jump.

Tuesday, August 8, 2017

July global surface temperature up 0.11°C

TempLS mesh anomaly (1961-90 base) was up from 0.568°C in June to 0.679°C in July. This follows the smaller rise of 0.06°C in the NCEP/NCAR index, and a similar rise (0.07) in the UAH LT satellite index. The July value is just a whisker short of July 2016, which was a record warm month. With results for Mexico and Peru still to come, that could change..

Again the dominant change was in Antarctica, from very cold in June to just above average in July. On this basis, I'd expect GISS to also rise; NOAA and HADCRUT not so much. Otherwise as with the reanalysis, Middle East and around Mongolia were warm, also Australia and Western USA. Nowhere very hot or cold. Here is the map:



Thursday, August 3, 2017

July NCEP/NCAR up 0.058°C

In the Moyhu NCEP/NCAR index, the monthly reanalysis average rose from 0.241°C in June to 0.299°C in July, 2017. This is lower than July 2016 but considerably higher than July 2015. The interesting point was a sudden rise on about July 24, which is responsible for all the increase since June. It may be tapering off now.

It was generally warm in temperate Asia and the Middle East, and even Australia. Antarctica was mixed, not as cold as June. The Arctic has been fairly cool.