Coherence of long-term lake ice records

Abstract

ice records are important in studies of climate (AsSEL& ROBERTSON1995) and aquatic ecosystems (MAGNUSONet aI. 1997). Further analysis of historicallake ice records is needed to improve knowledge of global cryospheric trends (FITZHARRIS1996). An International Workshop on Ice and Climate was held at the University of Wisconsin in 1996 (MAGNUSONet al. 2000) with the general goal of establishing a lake ice database and using it to analyze and interpret long-term ice data for their climatic and ecological content. The analysis described here is made under the auspices of an international Lake Ice Analysis Group (LIAG) established at that workshop. In this paper we present a preliminary analysis of 1) variations of long-term average ice-on, ice-off, and ice duration with latitude, and 2) an index of the coherence of ice event dates among five sites over the Northern Hemisphere with relatively continuous records from 1850 to 1995. Our objective is to provide information useful for the assessment and analysis of climate variability, climate change, and aquatic systems.