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

2. 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

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

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

5. 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

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

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

8. 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.

9. 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”

10. 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

11. 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
Drought Normal conditions Lot of Rain

12. 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

13. Summer Temperature

14. Geographical locations
Aker
Instrumental
Proxy

15. 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

16. Correlation
Significant trend

17. Winter temperature

18. Summer precipitation 1749 - 1835

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

20. 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.

21. 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.

22. 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.

23. 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

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