Graphic Lying
17 hours ago
Guest Post by Willis Eschenbach
An online friend of mine alerted me to a curious change in the Greenland Ice Sheet. From the Danish Polar Portal, here are two of their graphics.
Figure 1. Surface Mass Balance (SMB), polar year 2022-2023.
The Polar Portal site says:
The blue curve shows the current season’s surface mass balance measured in gigatonnes (1 Gt is 1 billion tonnes and corresponds to 1 cubic kilometre of water).
The dark grey curve traces the mean value from the period 1981-2010.
The light grey band shows differences from year to year. For any calendar day, the band shows the range over the 30 years (in the period 1981-2010), however with the lowest and highest values for each day omitted.
And what is the surface mass balance (SMB) when it’s at home? Again from the Polar Portal.
The difference between snowfall and runoff is known as the SURFACE mass balance. It is always positive over the course of a year as not all fallen snow runs off the ice sheet again.
The surface mass balance is NOT identical to the TOTAL mass balance (i.e. overall gain or loss of the ice cap), which also includes the mass that is lost when glaciers calve off icebergs, the melting of glacier tongues as they come into contact with warm seawater and frictional and other effects at the bottom of the ice sheet.
https://wattsupwiththat.com/2023/06/17/graphic-lying/
