Confusing Remote Sensing Systems (RSS) Temperature Update


The Remote Sensing System (RSS) has decided to switch to a version 3 much like the GHCN and UAH temperature sets have done in recent months.  As I have discussed each in turn I felt it only fair to discuss the differences in the RSS temperature set.  The GHCN change subtly enhanced the appearance of global warming.  The UAH was the most straightforward as the adjustment was a month by month (and spatial) adjustment to a new average temperature.

The RSS adjustment is just confusing.  There is no significant difference until January of 1999.  After that there is a small difference for each month, but there is no pattern to the adjustment.  1999-2000 show a small shift upwards in temperature while 2001-2010 show a decrease in temperature.  Nor is there a pattern by month.  This version change is the most confusing of them all.

The monthly average adjustment since 1999 is shown here.

The Inconvenient Skeptic

Average monthly change between RSS-v2 and RSS-v3 since 1999. Each year is different though and the average cannot be applied to each year.

The summer months showed the largest decrease, but the adjustment is smaller than the UAH and only applies to the last 11 years which all other version changes have affected the entire range.  This version is an unusual shift from the previous one.

Interestingly enough since the UAH was a more uniform shift in anomaly, there was almost no impact to the linear trend in temperature.  Since the RSS decreased the recent temperature only it resulted in a decrease in the warming trend even though the anomaly change was small.

Version 2 trend:  0.163C/decade

Version 3 trend:  0.149C/decade

The change in appearance is small, but again because the difference was only applied to recent data, it will create the appearance of less warming than version 2.

The Inconvenient Skeptic

Both versions of the RSS monthly anomaly data since 1998. Prior data is not shown there is only sporadic differences before 1999.

Since there is no pattern to the change it is not possible to regress the data back to version 2 from version 3.  For that reason I can only provide v3 updates from here forward.  So I will be using v3 data in all future uses.

Posted in Anomaly by inconvenientskeptic on February 13th, 2011 at 9:21 am.

4 comments

This post has 4 comments

  1. intrepid_wanders Feb 13th 2011

    It might be Roy Spencer’s baseline adjustment from the 20 year to the 30 year implemented this year (I can never argue with a baseline increase) and so the numbers to go lower.

    http://www.drroyspencer.com/2011/01/dec-2010-uah-global-temperature-update-0-18-deg-c/

    I think it was on a 20 year baseline because of the limited data series from RSS, but we have a little more data these days.

  2. intrepid_wanders Feb 13th 2011

    Nevermind, now I am confused as well. I read too fast the first time.

    Now I am leaning toward an adjustment based on seasonal variation. Spring and fall would have the smallest stdev from NH to SH and summer and winter would have the most… maybe that is the reason for the seasonal/variation correction factor? This is the kind on data series that hurts my head. Maybe Roy can shed some light.

  3. David Socrates Feb 15th 2011

    Rather than debating the reason for the RSS data adjustment here, guessing at the possibilities, why not just simply ask Roy Spencer. He is one of the most accessible of the cimate scientists (as befits a skeptic).

  4. inconvenientskeptic Feb 15th 2011

    Dr. Spencer is associated with the UAH. They both use the Advanced Microwave Sounding Unit (AMSU) data, but they are separate groups.

    I simply use the data and observe the changes to it over time. The UAH change was commented by Dr. Spencer and I found that the changes fit the explanation.

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