Temperature Update

World Climate Report provides monthly updates of satellite-measured temperatures around the globe.  These figures are measured by a series of platforms that sense mean temperatures of various layers in the atmosphere.  The one we routinely display is the lowest level, which matches perfectly with the mean temperatures measured by weather balloons between 5,000 and 28,000 feet.  The measurement is thought to be accurate to within ±0.01°C.

We compare these temperatures with surface values projected by the climate models that based the 1992 Framework Convention on Climate Change (the “Rio Treaty”).  Although it is difficult to strictly compare   surface projections and mean layer temperatures, the satellite provides great improvement over the surface record by supplying data over the entire planet.

May, 1996:  Primarily as a result of a quarter-degree cooling of the Southern Hemisphere, global temperature departures from average dropped a bit (.04°C) and now sit at –0.14°C.  The year 1996 continues to be a cool one, despite the lack of volcanic ash and the fact that there’s no big “La Niña” cooling in the tropical Pacific.  We are also beginning to suspect that the change between 1995 and 1996 temperatures is going to be pretty hefty because of cooling that occurred around the turn of the year.

Southern Hemisphere temperature departures from average were largest in the polar regions, with virtually all of the region surrounding Antarctica below the mean.  Regions southwest of both Australia and South America displayed anomaly values of more than 3°C below average. There were two small anomalies of +3°C located east of South America and over the extreme southwest Indian Ocean. The major cold anomaly in the Northern Hemisphere was a band of –3°C that covered most of Canada.   A much smaller warm feature, with a maximum of +4°C, was centered in the Russian Far East.

Despite the fact that the “El Niño” index is pretty much in the neutral range, satellite measurements over much of the Tropics, and especially over the tropical Pacific, were primarily below average.