Monthly Archives: January 2016

Global Temperature by Month 2015

Most people don’t realize that global temperature has a seasonal pattern dominated by the Northern Hemisphere because of much more land in the Northern Hemisphere than in the Southern Hemisphere and land is where the largest seasonal temperature variations occur.  Figure 1 shows the estimated average global temperature each month in 2015 and for the most recent climatic reference period 1981-2010 based on the University of Maine (UM) Climate Change Institute (CCI) Climate Forecast System Reanalysis (CFSR) data for comparison.  The CFSR data are derived from all the inputs to the Global Forecast System (GFS) weather forecast model runs four times each day.  For 2015 the largest monthly departures from the reference period were toward the end of the year, which also was the time that the latest El Niño was peaking, which could indicate a connection.  Notice there is almost a four degree Celsius (C) range from the coldest month January to the warmest month July.  The annual range in estimated global temperature dwarfs the individual monthly temperature anomalies relative to the reference period.

Global temperature by month

Figure 1. UM CCI CFSR estimated global temperature by month for 2015 and for the 1981-2010 reference period.

Figure 2 shows the UM CCI CFSR monthly global temperature estimates for 1979 through 2015.  As can be seen in the graph, the annual variations are much larger than the overall trend for the period, which is 0.0012C per month corresponding to 1.44C per century if maintained.  There also seems to be more variation from year to year at the low end of the annual range than at the high end.

Global monthly temperature trend

Figure 2. UM CCI CFSR global monthly temperature trend for 1979 through 2015.

Another interesting aspect of global temperatures is that trends for the average coldest month January and for the average warmest month July show some differences.  Figure 2 shows the trend of UM CCI CFSR January global average temperature estimates for 1979 through 2015 (click on the graph to enlarge), including the average of the daily maximums for the month, the average for the month, and the average of the daily minimums for the month.

Global temperature trend for January

Figure 3. UM CCI CFSR global temperature trend for January each year, including the average daily maximum, the average, and the average daily minimum.

Similarly, Figure 3 shows the July temperature trends.  Notice that for both January and July there is about a 4C difference between the monthly average minimum and maximum global temperature estimates.  The trends over the entire period are small compared to the average range within each month.

Global temperature trend for July

Figure 4. UM CCI CFSR global temperature trend for July each year, including the average daily maximum, the average, and the average daily minimum.

The January trend is +0.0134C per year which corresponds to +1.34C per century if maintained, while the July trend is slightly lower at +0.010C per year which corresponds to +1.00C per century.  The highest trend is +0.156C corresponding to +1.56C per century for the January average minimum global temperature estimates.  The lowest trend is +0.0087C per year corresponding to +0.87C for the July average minimum global temperature estimates.

Figure 4 shows an update of the latest UM CCI daily global temperature anomaly estimates for 2014 through today (2016 January 26).  The October 2015 through January 2016 period has been dominated by high spikes that may be related to the peaking El Niño event.  It will be interesting to see how the rest of the year evolves.

Global daily temperature anomalies

Figure 5. UM CCI CFSR global daily temperature anomalies for 2014 through 2016 January 26.

For for the latest CFSR daily and monthly updates to key figures, see the Daily Updates and Monthly Trends pages accessible from the menu bar at the top of this page.

Quick 2015 Update

The November and December 2015 daily Climate Forecast System (CFSR) global surface temperature anomaly estimates have been posted by the University of Maine Climate Change Institute (UM-CCI) and I used these estimates to create monthly estimates for November and December and an annual estimate for 2015.  UM-CCI also posted the final monthly anomalies for July through September 2015, so these have also been updated and are now final.  The University of Alabama at Huntsville (UAH) has posted their December global temperature for the lower troposphere (TLT) update which is included for comparison.  The annual UM-CCI CFSR and UAH TLT global temperature anomaly estimates are compared in Figure 1 for 1979 through 2015.

Annual global temperature anomalies for 1979-2015

Figure 1. Annual global temperature anomaly estimates for 1979 through 2015 from UM-CCI for surface CFSR and UAH for TLT.

The UM-CCI CFSR 2015 annual global temperature anomaly estimate of +0.28 degrees Celsius (C) ranks fifth highest since 1979, while the UAH TLT estimate of +0.28C ranks third highest since 1979.

The global temperatures during this period seem to exhibit two modes.  The period 1979 through 1997 shows an overall flat trend and appears to have been dominated by two strong stratospheric impacting volcanic eruptions as well as a strong La Niña.  The period 1998 through 2015 also shows an overall flat trend but offset about 0.3C higher than 1979-1997.  The 1998-2015 period was dominated by several strong El Niño events and had no major stratospheric impacting volcanic eruptions.

Figure 2 presents final monthly global temperature anomaly estimates for 2014 through 2015 from UM-CCI (surface CFSR), WxBell (surface CFSR), and UAH (TLT), and also compares the NCEI (surface) estimates through November 2015.  It will be interesting to see how much more the UAH TLT estimates rise in 2016 in response to the current El Niño, especially since it sometimes has shown a slightly lagged and higher rise for these events than surface estimates.

Monthly global temperature anomaly estimates for 2014 through 2015

Figure 2. Monthly global temperature anomaly estimates for 2014 through 2015.

Figure 3 graphs the daily UM-CCI CFSR daily global surface temperature anomaly estimates since 2014, including preliminary estimates for January 2016 so far (click to enlarge).  The upward jump beginning in October 2015 and continuing into early January 2016 may be a response to the current El Niño.  Time will tell.

Global Temperature Anomalies 2014-15 Daily CFSR

Figure 3. Daily UM-CCI CFSR global temperature anomaly estimates for 2014 through 2016 so far (click to enlarge).

For for the latest CFSR daily updates to key figures, see the Daily Updates page accessible from the menu bar at the top of this page.