Weather station history and introduced variability in climate data

Abstract

This chapter presents station histories as an important reference from which to identify or eliminate causes of variability and to explain or confirm the behavior of climatic data. Some apparent variability in climate data was introduced by changes in the weather station that recorded them. Significant changes in the observation rules occurred as the different networks evolved: the Surgeon General's, the Smithsonian's, the Signal Service's, the Weather Bureau's and the National Weather Service's. Each of them established rules for what to observe, what time to observe, how often to observe, and how to record. Location of stations, both initial and subsequent, changed in response to those rules. The resulting moves from frontier to populated areas, rural to urban, surface to roof top, and manual to automated produced changes in the data. Instrumentation changes and the exposures of those instruments caused differences in the measurements they made. In all of the networks, there were frequent changes in the observers. Their qualifications varied and in later years the observations became a corporate effort instead of an individual one. Each observer change presented an opportunity for the data to be unintentionally but systematically altered. © 2009 Springer Science+Business Media B.V.