Figure 8: Tropospheric temperature measurements by satellite MSU for North America between 30º to 70º N and 75º to 125º W (dark line) (17, 18) compared with the surface record for this same region (light line) (24), both plotted with 12-month smoothing and graphed as deviations from their means for 1979 to 1996. The slope of the satellite MSU trend line is minus 0.01 ºC per decade, while that for the surface trend line is plus 0.07 ºC per decade. The correlation coefficient for the unsmoothed monthly data in the two sets is 0.92.