Historical Documentary Records to Reconstruct Climate in Norway Elin Lundstad ECAC, Amsterdam, 1. oktober 2008

Participants in the Project Elin Lundstad, Statkraft, Norwegian Meteorological Institute Øyvind Nordli, Norwegian Meteorological Institute Martin Miles, Bjerknes Centre for Climate Research, Bergen, Norway Environmental Systems Analysis Research Center, Boulder, Colorado, USA

Outline for the Presentation Geographical location Data sources Objectives Methodology Results Proxydata Conclusions

Geographical location Scandinavia – Eastern Norway – Town Hamar Lake Mjoesa, Hamar Aker farm by the Lake Mjoesa and the town Hamar

Aker farm Aker is one of the oldest farm in the county of Hedmark. East of Norway. Archeological foundations here from 6th century. The name is from old Norwegian language and it mean religious place

Data sources The original Aker farm manuscript diaries were written by the military family Todderud over three generations in the period: 1749 - 1835. The diaries are kept at the public archives in Hamar.

The Weather Information Author Period Missing Information about the weather Years Average information Peder 1749 – 1771 123 23 5, 3 Barthold Henrick 1771 – 1804 1789 - 1796 1800 - 1801 4958 28 177 Eilert 1805 - 1835 23534 30 784 (2,1 pr day)

Objectives The objectives are to: Develop and improve methods to use these documentary records to reconstruct climate, particularly temperature and precipitation. Reconstruct climatic conditions there from 1749–1835, a period during the last part of the so-called Little Ice Age (LIA). Assess how well the diaries describe the late LIA weather and climate, compared with other climatic time series.

Kategorizing the Information Meteorological observations: Temperature, Precipitation, Cloud cover, Wind force and Wind direction Proxy data Parameteorological data: Ice-break dates, floods. Phenological data: Birch break dates, Dates for spring work The farmes descriptions and experiences: ”I can’t remember such warm spring like this before”

Methodology – the Index Method An index method was developed and used to quantify these qualitative climate-proxy observations In order to reconstruct temperatures and precipitation annually and for winter and summer. Temperature: Description of the thermal state is based on Todderud’s perception and is quantified by means of an index that represents the degree of warmth or cold or specific weather conditions

Methodology II Temperature: Precipitation: A similar index is used, including how many rainy days and how it affects growth and harvest farm. Wind force and direction, Cloud cover and climate anomalies are also considered here. Extraordinary Extraordinary cold Normal conditions warm -3 -2 -1 0 1 2 3 Drought Normal conditions Lot of Rain -3 -2 -1 0 1 2 3

Climate - the last 1000 Years Den lille istid (1550 – 1850): Kaldere somre, Mer nedbør på vinter og sommer, Økt breutbredelse, Uår og hungersnød (Klimaet 1749 – 1835) Kilde: CRU, Univ. East Anglia

Summer Temperature 1749 - 1835

Geographical locations Aker Instrumental Proxy

Results The reconstructed Aker series are compared with other climatic time series (both proxy and instrumental) using parametric and non-parametric methods, e.g., Spearman’s rank-correlation. Aker Austland Uppsala Oslo Femunden CET Haug • 0.77 0.44 0.71 0.31 0.51 0.25 0.60 0.79 0.40 0.58 0.76 0.33 0.52 0.67 0.70 0.12 0.32 C. England 0.36 Haug_lake Temperature: The Åker temperature series is strongly correlated (rs = 0.77) to another proxy temperature dataset based on the start of the grain harvest in eastern Norway for the same period (Nordli 2001) The Aker temperature series also correlated with a long instrumental temperature series from Uppsala, Sweden, though only moderate agreement is found, rs = 0.51. Significant: 0,01 Significant: 0,05 Not significant

Correlation Significant trend

Winter temperature 1749 - 1835

Summer precipitation 1749 - 1835

Average Wind Wind Data Annually 1805 - 1835 Wind speed Through the year

Climate anomalies 1749 - 1835 Koldest summer 1812 Varmest summer 1826 Storofsen 1789 – a flood A notable climate anomaly in the Åker diaries is the “Storofsen”, the biggest flood in eastern Norway in historical times.

A Late Winter-Early Spring Temperature Reconstruction for Southeastern Norway from 1758 to 2006 Large decadel variability, ice-break up data from lakes in Eastern Norway. Annals of glaciology 46, 2007 Øyvind Nordli, Norwegian Meteorological Institute Elin Lundstad, Norwegian Meteorological Institute Astrid E. J. Ogilvie, INSTAAR, University of Colorado, USA A significant temperature trend (2.5 oC) is detected for the whole period of 249 years. The 20th century was 1.3 oC warmer than the 19th century, whereas the 19th century was 0.4 oC warmer than the 43 last years of the 18th century The lowest temperatures of the series are seen during the Dalton sunspot minimum in the early 19th century The mild late winters – early springs in the 1990s and the start of the 21st century are unprecedented during the 249 years of the series.

Lakes Mälaren and Randsfjord Air temperature (FMA) reconstructions A significant temperature trend (2.5 oC) is detected for the whole period of 249 years. The 20th century was 1.3 oC warmer than the 19th century, whereas the 19th century was 0.4 oC warmer than the 43 last years of the 18th century The lowest temperatures of the series are seen during the Dalton sunspot minimum in the early 19th century The mild late winters – early springs in the 1990s and the start of the 21st century are unprecedented during the 249 years of the series.

Conclusions The climate reconstruction implies conditions consistent with the climate of the LIA. The climate in 1749–1835 was apparently both colder and wetter than today, and the year 1812 was especially cold. A comparison with other temperature series show the highest correlation with the Austlandsserien (Nordli, proxy data) and Oslo (instrumental). Uncertainties due to the method: the problem of subjectivity, both: the writer of the source (personal perceptions) and the reader (source criticme) Which is geographical nearest places The Aker diaries are unique: (what is new?) So much weather information in 86 year (one family) which is possible to reconstruct

Thank you for the attention! Special Thanks to Oyvind Nordli, Martin Miles and Ole Gjestvang. Met.no, UiB & Statkraft.