More on Tucson USHCN

Our Response To Recent Comments On Anthony Watts’ Blog by Ben Herman and Cyrus Jones

The accompanying Fig 1 shows a comparison of our data with the official NOAA data taken at Tucson International airport. From 1993 to 1996, the data was from our old site at the Medical School, taken with a non-aspirated temperature sensor. In May 0f 1997 the site was changed to its current location but data was still being taken with a non-aspirated sensor. The aspirated RM Young instrument was installed early in 1998 and has been in use since then. The installation of this new system is responsible for the drop in U of A temperatures relative to the NOAA temperatures since 1998. Indeed, non-aspirated instruments can read 4-5 degrees warmer than aspirated instruments during our hot sunny days.

The second figure presents our temperature data back to 1945 and also data from the NOAA airport station from 1948. I think it is quite clear that the 2 records follow each other very closely. Both show a definite warming trend. How much of this is due to the growth of Tucson and how much can be attributed to other causes is impossible to determine at this time, but the trend is clearly present in both data sets. [Emphasis mine.]

There are no “official” photos of the Tucson ASOS on the NCDC station locator, but I’ve managed to round up a couple. The first is from NOAA Surface Observations Program, taken in August 1996. The second is from NOAA Western Region Notes [PDF, top of page 3], taken sometime in 2005. Both photos indicate this is a “good” station.