A crop-based rainfall chronology for pre-instrumental record southern California

Abstract

Although measured climatic records begin in California about 1850, agricultural records from the earlier Spanish period can be used to develop information about annual precipitation. This historical material should be used, however, only with a full understanding of the numerous cultural variables that influenced agricultural production. A study by Iynch in 1931, which is widely cited in the literature of Pacific Coast climate reconstruction, contains serious shortcomings because of incorrect assumptions about the Spanish agricultural system, and, more specificaUy, the amount of climatic information expressed in yearly harvest data. In this article, mission data are analyzed more rigorously to produce a revised annual rainfall index for southern California that encompasses most of the pre-instrumental record period.

Historical evidence of a cold, dry summer during 1849 in the northeastern Great Basin and adjacent Rocky Mountains

“…Historical documents yield the highest frequency data out of all the proxy data types. To date, most of the successful historical climatological research has been focused on Europe and southeast Asia, but similar results have been derived for North America (Baron, 1982;Moodie and Catchpole, 1975;Catchpole and Ball, 1981;Rowntree, 1985;Lawson, 1974). Oliver and Kington (1970), Kington (1980), Douglas et al (1978), and Wilson (1985 demonstrated that historical documents can be used for synoptic weather reconstruction for daily and seasonal timescales.…”