What exactly is a monthly mean?

By Eco Guy 1:31am 22nd April 2010

A lot of climate analysis is done using the monthly mean temperature. Given that data is quite often available for hourly measurements I thought I'd have a look at whether creating a monthly mean straight off all the hourly measurements would produce a difference; initial findings indicate it does.

Luckily it seems that Cap and Trade is looking to become itself extinct and with good reason. See here for more detail on why its such a bad idea..

So what do we do instead? Global warming is clearly a 'none event' in terms of what we can do to control how the atmosphere changes; so I would say rather than focusing on things we cannot change, instead focus on what we can and what is evidently win/win situations.

For instance:

Research. Get out of finding ways to reduce carbon and instead focus on ways of making manufacturing processes more energy efficient and less polluting through the whole product life cycle.
Incentives. Set up tax breaks for manufacturers who produce goods that will last longer than 10 years without failure.
Reuse. Examine and set standards in markets that are currently fragmented through lack of standards - reward manufacturers who adopt standards that improve reuse.
Energy consumption. Again reward manufacturers who produce newer generations of products that do the same function but with a lower energy usage footprint.
Education: Actually spend time in schools educating people on how to live a more environmentally friendly life and 'dump' all the global warming/carbon trading rubbish.
Technology: actively support technologies which reduce our usage of transport - for instance working at home.

Basically there are lots of things we could be doing that have a much more meaningful impact on how we preserve the environment and reduce the rate of consumption of resources. We need to be thinking a lot longer term on these issues.

Related Content Tags: climate change, measurement

Comments left

Steven Mosher said:
There are several reasons why your derived value can be different from that given in GHCN.

1. Application of a TOBS correction in ghcn. which ghcn file are you using?

2. Averaging of duplicates in the ghcn file. for example if there are two instruments at the same location then GHCN will average these.

3. To calculate a monthly mean ghcn does this:

a. They take the daily min and daily max as defined by ( I believe ) a midnight time of observation. this is important and can cause differences.

b. The min figure is rounded. the max figure is rounded ( nearest F)

c. day ave = min+max/2. rounded. i believe, have to check the manual.

d. days are summed to the month

In general in studying hundreds of stations over decades you will find a difference between the "hourly" average and min/max average. But you wont find a trend bias, which is what matters.
ON Fri, 23 Apr 10, 4:43am probably from United States Reply to this comment
- Eco Guy said:
  In answer,
  
  ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/v2.mean.Z as downloaded on 21st Jan 10 for GIS model. not the _adj version. I have a ref to TOBS. I'll also try with the adjusted data.
  
  anyway to find out if they had multiple instruments at a location?
  
  wow on rounding the intermediate min/max - any reason given? Also do they define the rounding being done, i.e. nearest, up, down, 5up etc.
  
  Yep, there probably won't be a trend to see, but I'm actually more interested in the effect on confidence this introduces and if that varies over the months and temp ranges encountered. Easy enough for me to put in a DB and check, although wondering if this has been done before.
  ON Fri, 23 Apr 10, 8:45am probably from Australia Reply to this comment

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