README_stockholm_cloudiness.txt

This file describes the contents of a directory with files containing digitized
daily cloud observation data from the Stockholm Old
Astronomical Observatory (59.35N, 18.05E) 1756-2017.

Contact person:

Anders Moberg
Department of Physical Geography
Stockholm University
SE-10691 Stockholm, Sweden
anders.moberg@natgeo.su.se

2018-02-06


References:

Moberg A, Bergström H, Ruiz Krigsman J, Svanered O. 2002: Daily air temperature 
and pressure series for Stockholm (1756-1998). Climatic Change 53: 171-212

Moberg A, Alexandersson H, Bergström H, Jones PD. 2003: Were Southern Swedish 
summer temperatures before 1860 as warm as measured? 
Int. J. Climatol. 23: 1495-1521

Project:

IMPROVE - Improved Understanding of Past Climatic Variability from Early Daily 
European Instrumental Sources. EU 4th Framework Programme. Contract
ENV4-CT97-0511. 1998-1999. Co-ordinator: Dario Camuffo, Consiglio Nazionale
delle Ricerche, Istituto di Scienze dell'Atmosfera e del Clima, Padova, Italy.
PI at Stockholm University: Anders Moberg


Original data sources:

1756-1858: Archive of the Royal Swedish Academy of Sciences
1859-now:  Swedish Meteorological and Hydrological Institute (SMHI)

Data for 1756-1838 were digitized at the SMHI. Data for 1839-1960 were digitized
within IMPROVE. Data for 1961-onwards were provided digitally by the SMHI.


--- Directory contents ---

README_stockholm_cloud_obs.txt ( = this file )

stockholm_daily_cloud_obs_17560101_17840601_1_3.txt
stockholm_daily_cloud_obs_17840602_18151231_1_6.txt
stockholm_daily_cloud_obs_18160101_18410630_1_4.txt
stockholm_daily_cloud_obs_18410701_18581231_1_6.txt
stockholm_daily_cloud_obs_18590101_18721231_0_4.txt
stockholm_daily_cloud_obs_18730101_19601231_0_10.txt
stockholm_daily_cloud_obs_19610101_20121231_0_8.txt
stockholm_daily_cloud_obs_20130101_20171231_0_100.txt

Each data file is a plain ascii file with one day per row.
Columns 1-3 define the date, starting with 1756 01 01.
Columns 4-6 contain three daily observations (morning, noon, evening).

Missing observations are flagged with 'NaN'.

The observation hours are given by the file  
~/observation_hours/stockholm_daily_obs_hours_cet_1756_2017.dat.dat


stockholm_daily_cloud_obs_17560101_17840601_1_3.dat
	Data for 1756.01.01 to 1784.06.01 in a scale from 1 to 3
	
stockholm_daily_cloud_obs_17840602_18151231_1_6.dat
	Data for 1784.06.02 to 1815.12.31 in a scale from 1 to 6
	
stockholm_daily_cloud_obs_18160101_18410630_1_4.dat
	Data for 1816.01.01 to 1841.06.30 in a scale from 1 to 4
	
stockholm_daily_cloud_obs_18410701_18581231_1_6.dat
	Data for 1841.07.01 to 1858.12.31 in a scale from 1 to 6

stockholm_daily_cloud_obs_18590101_18721231_0_4.dat
	Data for 1859.01.01 to 1872.12.31 in a scale from 0 to 4

stockholm_daily_cloud_obs_18730101_19601231_0_10.dat
	Data for 1873.01.01 to 1960.12.31 in a scale from 0 to 10
	
stockholm_daily_cloud_obs_19610101_20121231_0_8.dat
	Data for 1961.01.01 to 2012.12.31 in a scale from 0 to 8

stockholm_daily_cloud_obs_20130101_20171231_0_100.txt
	Data for 2013.01.01 to 2015.12.31 in a scale from 0 to 100

Note! Moberg et al. (2003) concluded that these clound amount data could not be
used to produce a homogenized and reliable long record of changes in cloud
amount.

Appendix A in Moberg et al. (2003) describes the various procedures used to
observe cloud amount in different time periods. The different scales used in
the data files correspond to the different cathegories used in Table X of their
Appendix A, as follows (Swedish original terms and English translations):

1756.01.01 to 1784.06.01

1 = Klart
    Clear

2 = Strömoln, dunkelt, töknigt, eller rök
    Scattered clouds, gloomy, misty, or haze

3 = Mulet, dimba, regn, urväder, eller snö¶
    Cloudy, fog, rain, stormy weather, or snow

1784.06.02 to 1815.12.31

1 = Klar himmel
    Clear sky

2 = Ganska glesa moln, eller himmelen nästan klar
    Rather sparse clouds, or almost clear sky

3 = Glesa moln
    Sparse clouds

4 = Himmelen half mulen
    Half cloudy sky

5 = Himmelen nästan helt mulen
    Almost completely cloudy sky

6 = Himmelen Öfver allt mulen, dimba, rägn, eller snö¶
    Completely cloudy sky, fog, rain, or snow

1816.01.01 to 1841.06.30

1 = Klart
    Clear

2 = Halvklart
    Half clear

3 = Strömoln
    Scattered clouds

4 = Mulet, eller dimma
    Cloudy, or fog

1841.07.01 to 1858.12.31

1 = Klart
    Clear

2 = Mest klart
    Mostly clear

3 = Halvklart
    Half clear

4 = Strömoln
    Scattered clouds

5 = Mest mulet
    Mostly cloudy

6 = Mulet
    Cloudy

1859.01.01 to 1872.12.31

Cloud amount in fourths (0-4)

1873.01.01 to 1960.12.31

Cloud amount in tenths (0-10)

1961.01.01 to 2012.12.31

Cloud amount in oktas (0-8) 
Note, the code '9' is also used and denotes fog.

2013.01.01 to 2017.12.31

Cloud amount in hundredths (0-100), 
as downloaded from SMHI Öppna Data,
http://opendata-download-metobs.smhi.se/explore/#
Note! There exist some cases after 2013.01.01 where the reported cloud amount is >100
      The reason for this has not been investigated.