Friday, September 17, 2010

Beta version of GHCN v3 is out.

Beta version of GHCN v3

h/t CCE (at Whiteboard).
I've only recently read CCE's comment - I've downloaded v3 from here. It's late where I am, so this is very much a first impression.

The README file is helpful. The inventory file has a new layout, so TempLS will need some changes to read it. It seems to have basically the same data, though, about the same 7280 stations as v2.

The data file also seems to have much the same actual data. But interspersed are a number of codes. There is a measurement code and a quality code, but not yet used, except for USHCN. Then there is a source code (saying where the data comes from).

So there's work to do to get TempLS to read it. It's not clear that this beta version has data changes that will affect the results. But we'll see.
Update below the jump:

Monday, September 13, 2010

GISS for August 0.53C, same as July

GISS is rather early this month - seems to be even before MSU-RSS. It's the one index that had been falling rather rapidly, so no change is a change.

The monthly land/ocean global plots below are from Moyhu's monitoring page.

Friday, September 3, 2010

A very different gridding method - TempLS

Station-based monthly global temperature indices use gridding at some stage, and usually the grid cells follow some regular rule, like a lat/lon square. This causes some problems:
  • Minor - cells are unevenly populated with stations.
  • Major - some cells have no data in some months
These can be avoided with the use of irregular grid cells, which can be smaller when stations are dense, and can be formed with a requirement that they always have at least one data point.
There are needs here which make well-known unstructured meshes like Voronoi unsuitable. This post describes one based on binary trees.