Articles | Volume 12, issue 11
Research article
18 Nov 2016
Research article |  | 18 Nov 2016

Jens Esmark's Christiania (Oslo) meteorological observations 1816–1838: the first long-term continuous temperature record from the Norwegian capital homogenized and analysed

Geir Hestmark and Øyvind Nordli

Abstract. In 2010 we rediscovered the complete set of meteorological observation protocols made by Jens Esmark (1762–1839) during his years of residence in the Norwegian capital of Oslo (then Christiania). From 1 January 1816 to 25 January 1839, Esmark at his house in Øvre Voldgate in the morning, early afternoon and late evening recorded air temperature with state-of-the-art thermometers. He also noted air pressure, cloud cover, precipitation and wind directions, and experimented with rain gauges and hygrometers. From 1818 to the end of 1838 he twice a month provided weather tables to the official newspaper Den Norske Rigstidende, and thus acquired a semi-official status as the first Norwegian state meteorologist. This paper evaluates the quality of Esmark's temperature observations and presents new metadata, new homogenization and analysis of monthly means. Three significant shifts in the measurement series were detected, and suitable corrections are proposed. The air temperature in Oslo during this period is shown to exhibit a slow rise from 1816 towards 1825, followed by a slighter fall again towards 1838.

Short summary
The detailed and continuous meteorological observations of Jens Esmark from the capital of Norway in the period 1816 to 1838 are evaluated, homogenized and reanalysed with modern methods to characterize the weather in Oslo in this period.