[{"name":"stockholm-historical-daily-slp-1","title":"Stockholm Historical Weather Observations \u2014 Sub-daily sea level pressure since 1756","summary":"Data for sub-daily sea level pressure (SLP) at the old astronomical observatory in Stockholm are provided for the period 1756\u2060\u200a\u2013\u200a2012.\r\n\r\nThree SLP values per day are typically available. Two variants are presented: (i) Homogenized SLP data, (ii) Non-homogenized SLP data. The non-homogenized data provide SLP values calculated directly from the observations. \r\n\r\nThe homogenized SLP data have been corrected for known or supposed biased barometers and have been adjusted such that the long term trend agrees with other long air pressure measurements from stations in Northern Europe. Nevertheless, the homogenized record is judged to not reliably represent long-term trends in air pressure throughout the entire period, but the short term day-to-day changes are likely rather accurate.","citations":"Moberg A, Bergstr\u00f6m H, Ruiz Krigsman J, Svanered O. 2002: Daily air temperature and pressure series for Stockholm (1756\u20131998). Climatic Change 53: 171\u2013212. DOI:10.1023\/A:1014966724670","comments":"The observation site is included in the national station network managed by the Swedish Meteorological and Hydrological Institute (SMHI), with station number 98210 (manual station) and 98230 (automatic station), but data in the current dataset can differ from those in the SMHI database.\r\n\r\n\r\nBarometer observations have been made daily since 1756. The oldest barometer measured the height of the mercury column in Swedish inches (=29.69 mm). No thermometer was attached and the temperature near the barometer was not observed before 1785. The lack of temperature observations, an unknown exact height of the barometer position and other unkown properties of old barometers used make it difficult to convert the oldest barometer recordings to the modern unit of hPa reduced to 0\u00b0C, normal gravity and sea level. Despite these difficulties, efforts have been made to convert all individual observations to hPa back to 1756. Homogenization of the record has been done by adjustments such that the long term trend agrees with other long air pressure records from Northern Europe. Details of how this was achieved are provided in Moberg et al. (2002).\r\n\r\n\r\nThe sub-daily SLP series from Moberg et al. (2002) covers the period 1756\u2060\u200a\u2013\u200a1998. Updating to the end of 2012 has been made here by merging with data obtained from the SMHI. No more recent values are included. However, sub-daily SLP values for 2013\u2060\u200a\u2013\u200a2018 are available in the associated dataset with  barometer observations in original units. Those data are in turn obtained from the SMHI resource \u00d6ppna Data. If required, those data files can be used to extend the long sub-daily SLP records in time to the most present.\r\n\r\n\r\nThe number of observations each day has changed through time, as follows:\r\n\r\n1756-01-01\u2060\u200a\u2013\u200a1784-05-31: 2 observations (morning and evening)\r\n\r\n1785-06-01\u2060\u200a\u2013\u200a2012-12-31: 3 observations (morning, noon, evening)\r\n\r\n\r\nInformation about instruments and original data sources is available in the comments to the associated dataset with barometer observations in original units.","category":"Atmosphere","subcategory":"Weather observations","keywords":"Air pressure; Barometer; Daily data; Early instrumental data; Homogenized data; Sweden; Stockholm","scientist":"Anders Moberg","firstname":"Anders","lastname":"Moberg","address":"Department of Physical Geography, Stockholm University","postalcode":"SE-106 91","city":"Stockholm","province":"","country":"Sweden","parameters":"Earth science > Atmosphere > Atmospheric pressure > Sea level pressure","location":"Continent > Europe > Northern Europe > Scandinavia > Sweden","progress":"Completed","language":"English","project":"Digitization, quality control and development of daily and monthly air temperature and pressure data series until 1998 was undertaken as part of the project IMPROVE \u2014 Improved Understanding of Past Climatic Variability from Early Daily European Instrumental Sources. Project funding: EU 4th Framework Programme, 1998\u20131999. Contract: ENV4-CT97-0511. Co-ordinator: Dario Camuffo, Consiglio Nazionale delle Ricerche, Istituto di Scienze dell'Atmosfera e del Clima, Padova, Italy. PI at Stockholm University: Anders Moberg.","publisher":"Bolin Centre Database","version":"1","constrains":"None","access":"Free"}]