JLI Final Forecasts for 2014

Solomon Green says: March 8, 2014 at 1:57 am
Can anyone explain why the Met Office refers its prediction on a long term (1961-1990) average? Why not (1951-1980) or (1971-1990) or the most recent (1981-2010)? Is it because the anomaly may look higher when using 1961-1990 as the base? Or is it because they might find it difficlult to exclude UAH and RSS from their averages if they selected the later periods?
They should be using 1981–2010 as their base period “in order to comply with a recommended World Meteorological Organization (WMO) Policy, which suggests using the latest decade for the 30-year average.”
http://www.ncdc.noaa.gov/cmb-faq/anomalies.php
However, HadCRUT4, “time series are presented as temperature anomalies (deg C) relative to 1961-1990.”
http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/download.html
According to the UEA CRU:
“Why are the temperatures expressed as anomalies from 1961-90?
Stations on land are at different elevations, and different countries measure average monthly temperatures using different methods and formulae. To avoid biases that could result from these problems, monthly average temperatures are reduced to anomalies from the period with best coverage (1961-90). For stations to be used, an estimate of the base period average must be calculated. Because many stations do not have complete records for the 1961-90 period several methods have been developed to estimate 1961-90 averages from neighbouring records or using other sources of data (see more discussion on this and other points in Jones et al. 2012). Over the oceans, where observations are generally made from mobile platforms, it is impossible to assemble long series of actual temperatures for fixed points. However it is possible to interpolate historical data to create spatially complete reference climatologies (averages for 1961-90) so that individual observations can be compared with a local normal for the given day of the year (more discussion in Kennedy et al. 2011).”
The UEA CRU explanation incoherent, thus as you say, it is probably “because the anomaly may look higher when using 1961-1990 as the base”.
For reference for:
UAH “the global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average”;
http://www.drroyspencer.com/2013/04/uah-global-temperature-update-for-march-2013-0-18-deg-c-again/
GISS “anomalies are relative to the 1951-80 base period means”;
http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt
HadCRUT4 “time series are presented as temperature anomalies (deg C) relative to 1961-1990”;
http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/download.html
RSS “anomalies are computed by subtracting the mean monthly value (averaged from 1979 through 1998 for each channel) from the average brightness temperature for each month”;
http://www.ssmi.com/msu/msu_data_description.html#rss_msu_data_analysis
NOAA NCDC “the global and hemispheric anomalies are provided with respect to the period 1901-2000, the 20th century average.”
However, they also note that, “beginning in December 2010, all lower troposphere, middle troposphere, and lower stratosphere satellite data are reported here with respect to the 1981–2010 base period. Prior to December 2010, data were reported with respect to the 1979–1998 base period. Remote Sensing Systems continues to provide data to NCDC with respect to the 1979–1998 base period; however, NCDC readjusts the data to the 1981–2010 base period so that the satellite measurements are comparable.”
In terms of “why do some of the products use different reference periods?” NOAA NCDC states that:
“the maps show temperature anomalies relative to the 1981–2010 base period. This period is used in order to comply with a recommended World Meteorological Organization (WMO) Policy, which suggests using the latest decade for the 30-year average. For the global-scale averages (global land and ocean, land-only, ocean-only, and hemispheric time series), the reference period is adjusted to the 20th Century average for conceptual simplicity (the period is more familiar to more people, and establishes a longer-term average). The adjustment does not change the shape of the time series or affect the trends within it.”
http://www.ncdc.noaa.gov/cmb-faq/anomalies.php
“NOAA’s Climate Prediction Center has already changed their Normals to the 1981 – 2010 base period? Why are those Normals not available?
Many organizations, including NOAA’s Climate Prediction Center (CPC), develop their own averages and change base periods for internal use. However, NCDC’s climate Normals are the official United States Normals as recognized by the World Meteorological Organization and the main Normals made available for a variety of variables.”
http://www.ncdc.noaa.gov/cmb-faq/anomalies.php
NOAA Climate Prediction Center’s CAMS station temperature anomaly dataset. “CAMS” is an acronym for the “Climate Anomaly Monitoring System” in use at the Climate Prediction Center (CPC). “CAMS station surface air temperature anomalies for the globe with respect to the 1971-2000 climatological base period.”
http://iridl.ldeo.columbia.edu/maproom/Global/Atm_Temp/Monthly_stn_anom.html

Steven Mosher says: March 8, 2014 at 7:13 am
So let me answer your first question again
Of course we have an Idea of what is going to happen. It’s pretty simple. some people have an Idea that El nino may happen. It’s pretty clear what that means. I have an idea that the sun may go down today. The fact that I am uncertain about it doesnt make it any less of an idea.
So now you want to argue about the meaning of the word “idea”? The point is that during February to May our predictive capacity as it relates to ENSO is essentially nil, i.e. “The period from February through May is commonly referred to as the spring barrier. During this time, models generally have the least skill to predict the coming season.”
http://iri.columbia.edu/news/la-nina-still-hanging-on/
Parsing out the meaning of the words “May” and “Is” would be Philosophy son not law.
That’s funny, and I am even more amused by the thought of Bill Clinton as a modern day philosopher, but having dealt with contract law, I’d argue that a good attorney could hold their own against any philosopher in arguing about the meaning of a word ad nauseam.
I find it ironic with your name “Just the facts” that you dont pay more attention to facts which are about what ‘is’ and ideas which can be about what “may” exist.
funny actually.
I am glad that you can amuse yourself. Perhaps you could set aside a bit of time to do some research on what’s going to happen with ENSO this year? You are clearly outwordsmithing me, but in terms of our lack of predictive capacity, you haven’t presented any evidence to the contrary.
Of course there is probable knowledge.
You seem to think you’ve stumbled on to some philosophy thread, we’re taking about “probable knowledge” about what’s going to happen with ENSO and global temperatures this year. Your perception of “probable knowledge” seems to encompass laying out the options, i.e. it might get warmer, it might get colder or it might stay the same. Show us a shred of evidence that anyone has any predictive capacity as to what ENSO will do this year.
Further citing yourself to make an argument is really funny.
I am not citing myself, I am citing the dozens of quotes and references within the article and thread that support the fact that we cannot accurately predict global temperatures a few months into the future, much less a few years or decades…