Abstract: The Hildreth-Lu procedure, which corrects for serial correlation in time-series data, was applied to most of the same cities as previously analyzed via ordinary least squares (OLS).

Three major findings were:

(1) No serial correlation was detectable within the 55-year MAXTMP trend line data analyzed, and

(2) the OLS and Hildreth-Lu trend lines, standard errors of estimate and t-stat values were essentially identical, i.e., absence of serial correlation, and

(3) The analyzed data are consistent with the hypothesis that, for cities with sufficiently small populations such that the urban heat island effect is minimal, the natural long-term trend (observable in the absence of urban heat island effects) is negative. That is, the net annual rate of temperature change is negative for small-population cities.

MAXTMP temperature data, °F per year, courtesy of NCDC and NOAA, were analyzed for eleven cities from among the three states: AZ, GA, and MN.

Major focus of the study was directed to three of the cities with smallest populations, namely: Winslow, AZ; Camilla, GA; and Faribault, MN, whose July 2002 populations were 9746, 5672, and 21340, respectively.

As shown in the .pdf formatted report, "Global Cooling in the U.S.?," Camilla, GA, representing the city with lowest population from among the cities studied, demonstrated most persuasively that, during the past 55-years, its net annual rate of temperature change was negative.

Moreover, throughout the 55-year trend, the most recent 24-years (1949 - 2002) displays the highest rate of cooling (see report: Camilla Addendum).

It is noteworthy that Mt. St. Helens erupted during May, 1980.

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