Guest Post By Walter Dnes
In continuation of my Temperature Anomaly projections, the following are my January projections, as well as last month’s projections for December, to see how well they fared.
The Data Sources
The latest data can be obtained from the following sources
- HadCRUT4 http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.22.214.171.124.monthly_ns_avg.txt
- GISS https://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt The GISS site has switched from “http” to “https” (i.e. secure http) and may require upgrading “wget” if you use it to retrieve the data.
- UAH http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/tltglhmam_6.0.txt
- RSS ftp://ftp.ssmi.com/msu/monthly_time_series/rss_monthly_msu_amsu_channel_tlt_anomalies_land_and_ocean_v03_3.txt
- NCEI https://www.ncdc.noaa.gov/cag/time-series/global/globe/land_ocean/p12/12/1880-2016.csv
At the time of posting all 5 monthly data sets were available through December 2016. The NCEP/NCAR re-analysis data runs 2 days behind real-time. Therefore, real daily data through January 29th is used, and the 30th and 31st are assumed to have the same anomaly as the 29th.
The projections are derived from the previous 12 months of NCEP/NCAR anomalies compared to the same months’ anomalies for each of the 5 data sets. For each of the 5 data sets, the slope() value (“m”) and the intercept() value (“b”) are calculated. Using the current month’s NCEP/NCAR anomaly as “x”, the numbers are plugged into the high-school linear equation “y = mx + b” and “y” is the answer for the specific data set. The entire globe’s data is used for HadCRUT, GISS, and NCEI. For RSS and UAH, subsets of global data are used, to match the latitude coverage provided by the satellites.
A sharp spike in daily anomalies in the last 10 days of January has pushed the projected values to their highest level since April 2016.
The graph immediately below is a plot of recent NCEP/NCAR daily anomalies, versus 1994-2013 base, similar to Nick Stokes’ web page. The second graph is a monthly version, going back to 1997. The trendlines are as follows…
- Black – The longest line with a negative slope in the daily graph goes back to early July, 2015, as noted in the graph legend. On the monthly graph, it’s August 2015. This is near the start of the El Nino, and nothing to write home about. Reaching back to 2005 or earlier would be a good start.
- Green – This is the trendline from a local minimum in the slope around late 2004, early 2005. To even BEGIN to work on a “pause back to 2005”, the anomaly has to drop below the green line.
- Pink – This is the trendline from a local minimum in the slope from mid-2001. Again, the anomaly needs to drop below this line to start working back to a pause to that date.
- Red – The trendline back to a local minimum in the slope from late 1997. Again, the anomaly needs to drop below this line to start working back to a pause to that date.
NCEP/NCAR Daily Anomalies:
NCEP/NCAR Monthly Anomalies: