Skip to content

Antarctic Temperature Trends

October 19, 2014
tags:

By Paul Homewood

 

It has been claimed that atmospheric temperatures over the Antarctic have been increasing in recent years.

Satellite measurements from both UAH and RSS, which date back to 1979, tell a different tale.

 

image

http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc_lt_5.6.txt

 

image

http://data.remss.com/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_3.txt

 

Both datasets show a small declining trend. Any increase in recent years is merely a recovery from the sharp drop in temperatures between 1998 and 2000.

Notably, the peaks seen in the last decade are lower than others recorded earlier in the record.

 

 

The RSS series is particularly relevant as far as sea ice is concerned, as the area covered only covers 60S – 70S, giving a fairly good match to the area affected by sea ice. UAH, in contrast, goes to 85S, thus covering much of the land mass.

 

In conjunction with the fact that Southern Ocean Sea Surface Temperatures have been falling sharply during the last decade, we don’t particularly have to look for exotic reasons as to why sea ice is increasing.

 

14southern_thumb

http://bobtisdale.wordpress.com/2014/10/12/september-2014-sea-surface-temperature-sst-anomaly-update/

Advertisements
35 Comments
  1. October 19, 2014 3:06 pm

    Hi Paul,
    you should have told me that you were going to do this. I just finished UAH. Got the same trend as you found, [I think]
    -0.0003K/annum since 1979, essentially flat.
    But there is something wrong with UAH. Like I told you. It even looks suspicious. Look at the difference between UAH and RSS from 2010.

    Could you give me your trend in K/annum for RSS (60S-70S) since 1995 (by selecting only the data from 1995 onwards?

    • October 19, 2014 4:05 pm

      7.160E-006

      • October 19, 2014 4:32 pm

        Thanks. OK. That is also essentially flat (zero). What happens [at the trend] when we look at RSS from 2002? It seems to me here lies the steepest part of the [current] downward trend?

        fyi I am trying to explain [to myself] where the extra ice is coming from….

      • October 19, 2014 6:41 pm

        My belief is that the oceans are playing the major part. We know that the incursion of warm water from lower latitudes was responsible for much of the Arctic melt.

        Now we find the reverse in the Antarctic, with colder sea and more ice. (Colder seas mean that there has been less incursion of warm water and less transfer of cold water to lower latitudes.

        Why these events happen, nobody knows (honestly!), but the heat capacity of the ocean is so immense that when these changesdo happen, they can have a significant effect.

        Also, movement & changes in ocean currents occur over decades. What we are seeing now could well be a knock on from events 50 yrs ago or more. Warmist claims that these things are a result of a few years of global warming are frankly nonsense.

  2. October 19, 2014 3:25 pm

    btw
    Paul, could you perhaps also give me your actual measured trend that you get for RSS 60S -70S in K/annum from 1979?
    i

  3. October 19, 2014 6:12 pm

    I asked RSS why they didn’t cover the antarctic as far south as UAH.
    This was their reply:

    “For TLT, over the south pole, we concluded that too much (as much as 30-40%)
    of the signal comes from the surface, not the atmosphere. Much of the ice sheet is
    above 3000 meters, so there is not enough atmosphere left to get a good
    measurement for TLT. Or, if you look at the figure on the website for the weighting function
    for TLT, imagine the the surface sitting 3000 meters high in that diagram.
    For TMT, which peaks high in the atmosphere, much more of
    the signal comes from the atmosphere for regions where the surface of the
    earth is at high altitude.

    UAH covers everywhere, though the information right at the poles is extrapolated
    because the satellites never measure there.”

    • October 19, 2014 6:42 pm

      Thanks, I remembered your comment before, but could not find it!

      I’ll save it this time.

  4. October 19, 2014 7:37 pm

    Dear Paul
    This is really terribly important [to me]
    I did not do RSS now, because I knew you already did it.
    For UAH (SoPole) I get +0.0034K/annum since 2002, which I know is wrong because all data sets including my own go against that finding…

    Please check if I am right and let me know what you get for RSS since 2002?

    • October 19, 2014 9:50 pm

      It’s the shift in the PDO.

      There was a massive warming step around 1976 in Alaska, when the PDO went positive,and now it has reversed.

  5. October 19, 2014 10:19 pm

    Thanks, Paul. Good article.

  6. David permalink
    October 20, 2014 11:28 am

    I don’t think anyone has argued that the trend in Antarctic temperatures isn’t more or less flat since 1979. The question was, can we blame air temperatures for the recent increase in Antarctic sea ice extent? I don’t see how we can.

    Paul mentions a recovery post 2000. Indeed, annual air temperatures during the 13-year period 2001-13 were warmer than in the preceding 13 year period, 1988-2000, in both RSS (-70 to -60) and UAH (SoPol/Ocean). Yet average annual Antarctic sea ice extent in 2001-13 was 12.21m km^2 and in 1988-2000 it was 11.98 m km^2.

    There is an inverse relationship. Paradoxical as it seems, Antarctic sea ice extent was lower on average than it is now during a 13 year period when Antarctic air temperatures were colder on average than they are now. How then can air temperatures be blamed for the sea ice extent increase since 2001?

    • October 20, 2014 11:54 am

      Clue – Colder oceans?

      Look at the graph, temperatures go up and down, but temperatures in recent years are perfectly normal. This suggests that increased ice has nothing at all to do with air temperatures, either cold or warm.

      • David permalink
        October 20, 2014 3:44 pm

        I’m not suggesting that the southern ocean SST hasn’t cooled, just that air temperatures haven’t either, at least not to any significant extent.

        Whatever cooled the Southern Oceans around Antarctica, it wasn’t the local air temperatures above them.

      • October 20, 2014 4:07 pm

        I am not saying it was.

    • October 20, 2014 5:47 pm

      They are not measuring correctly?

  7. October 20, 2014 4:54 pm

    I must say that I still doubt that value of -0.005C/annum since 2002 (60S-70S)
    There are no base weather stations in that area because there is no land. How can ice be increasing unless both seawater and air temps. are going down?
    Another question that comes up: how good are the gauges and how good is the calibration for the ultra low temperatures we want to investigate?

  8. October 20, 2014 5:27 pm

    What I do know is that in Alaska 60N-70N it is cooling at a rate of -0.055K/annum since 1998.
    Why would anyone think that global cooling is not happening symmetrical?

  9. October 20, 2014 7:26 pm

    The format of reply and answer here is a bit confusing.
    Yes, I was asking how we can verify any of the results from RSS or UAH?
    If you do not have any base weather station?

  10. October 20, 2014 7:32 pm

    I bet you if do an investigation on the NoPole data from RSS or UAH I still wont get same -0.055K/annum for 60N-70N?
    It will have to wait until next weekend….
    Unless you have more time than me?

Comments are closed.

%d bloggers like this: