"The errors in the record exceed by a wide margin the purported rise in temperature of 0.7º C (about 1.2º F) during the twentieth century. Consequently, this record should not be cited as evidence of any trend in temperature that may have occurred across the U.S. during the past century. Since the U.S. record is thought to be “the best in the world,” it follows that the global database is likely similarly compromised and unreliable. "
Anthony Watts
Looks to me like they're using grapes to compare apples and oranges.
ReplyDeleteThe measurement devices were likely installed to provide local weather data to compare a place to itself - is today warmer than yesterday.
But then someone decided that since all these data are available and they should be mined or a different purpose - to measure regions or national averages. Which the devices were likely never designed to do.