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Carlund, Thomas
Publications (10 of 11) Show all publications
Lopez-Solano, J., Redondas, A., Carlund, T., Rodriguez-Franco, J. J., Diemoz, H., Leon-Luis, S. F., . . . Karppinen, T. (2018). Aerosol optical depth in the European Brewer Network. Atmospheric Chemistry And Physics, 18(6), 3885-3902
Open this publication in new window or tab >>Aerosol optical depth in the European Brewer Network
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2018 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 6, p. 3885-3902Article in journal (Refereed) Published
National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-4565 (URN)10.5194/acp-18-3885-2018 (DOI)000427962300002 ()
Available from: 2018-04-10 Created: 2018-04-10 Last updated: 2018-04-10Bibliographically approved
Landelius, T., Andersson, S., Carlund, T. & Josefsson, W. (2018). Karteringen av solstrålningen i Sverige. Polarfront (168), 31-40
Open this publication in new window or tab >>Karteringen av solstrålningen i Sverige
2018 (Swedish)In: Polarfront, no 168, p. 31-40Article in journal (Other academic) Published
Place, publisher, year, edition, pages
Svenska Meteorologiska Sällskapet, 2018
National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-5157 (URN)
Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Kazadzis, S., Kouremeti, N., Diemoz, H., Grobner, J., Forgan, B. W., Campanelli, M., . . . Wehrli, C. (2018). Results from the Fourth WMO Filter Radiometer Comparison for aerosol optical depth measurements. Atmospheric Chemistry And Physics, 18(5), 3185-3201
Open this publication in new window or tab >>Results from the Fourth WMO Filter Radiometer Comparison for aerosol optical depth measurements
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2018 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 5, p. 3185-3201Article in journal (Refereed) Published
National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-4559 (URN)10.5194/acp-18-3185-2018 (DOI)000426906400002 ()
Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2018-03-27Bibliographically approved
Carlund, T., Kouremeti, N., Kazadzis, S. & Grobner, J. (2017). Aerosol optical depth determination in the UV using a four-channel precision filter radiometer. Atmospheric Measurement Techniques, 10(3), 905-923
Open this publication in new window or tab >>Aerosol optical depth determination in the UV using a four-channel precision filter radiometer
2017 (English)In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 10, no 3, p. 905-923Article in journal (Refereed) Published
National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-4044 (URN)10.5194/amt-10-905-2017 (DOI)000397797800004 ()
Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2017-11-29Bibliographically approved
Riihela, A., Carlund, T., Trentmann, J., Mueller, R. & Lindfors, A. V. (2015). Validation of CM SAF Surface Solar Radiation Datasets over Finland and Sweden. Remote Sensing, 7(6), 6663-6682
Open this publication in new window or tab >>Validation of CM SAF Surface Solar Radiation Datasets over Finland and Sweden
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2015 (English)In: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 7, no 6, p. 6663-6682Article in journal (Refereed) Published
Abstract [en]

Accurate determination of the amount of incoming solar radiation at Earth's surface is important for both climate studies and solar power applications. Satellite-based datasets of solar radiation offer wide spatial and temporal coverage, but careful validation of their quality is a necessary prerequisite for reliable utilization. Here we study the retrieval quality of one polar-orbiting satellite-based dataset (CLARA-A1) and one geostationary satellite-based dataset (SARAH), using in situ observations of solar radiation from the Finnish and Swedish meteorological measurement networks as reference. Our focus is on determining dataset quality over high latitudes as well as evaluating daily mean retrievals, both of which are aspects that have drawn little focus in previous studies. We find that both datasets are generally capable of retrieving the levels and seasonal cycles of solar radiation in Finland and Sweden well, with some limitations. SARAH exhibits a slight negative bias and increased retrieval uncertainty near the coverage edge, but in turn offers better precision (less scatter) in the daily mean retrievals owing to the high sampling rate of geostationary imaging.

National Category
Meteorology and Atmospheric Sciences
Research subject
Meteorology
Identifiers
urn:nbn:se:smhi:diva-1968 (URN)10.3390/rs70606663 (DOI)000357589800007 ()
Available from: 2016-04-26 Created: 2016-03-03 Last updated: 2017-11-30Bibliographically approved
Melin, F., Zibordi, G., Carlund, T., Holben, B. N. & Stefan, S. (2013). Validation of SeaWiFS and MODIS Aqua/Terra aerosol products in coastal regions of European marginal seas. Oceanologia, 55(1), 27-51
Open this publication in new window or tab >>Validation of SeaWiFS and MODIS Aqua/Terra aerosol products in coastal regions of European marginal seas
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2013 (English)In: Oceanologia, ISSN 0078-3234, Vol. 55, no 1, p. 27-51Article in journal (Refereed) Published
Abstract [en]

The aerosol products associated with the ocean colour missions SeaWiFS and MODIS (both Aqua and Terra) are assessed with AERONET field measurements collected in four European marginal seas for which fairly large uncertainties in ocean colour in-water products have been documented: the northern Adriatic, the Baltic, Black and North Seas. On average, more than 500 match-ups are found for each basin and satellite mission, showing an overall consistency of validation statistics across the three missions. The median absolute relative difference between satellite and field values of aerosol optical thickness tau(a) at 443 nm varies from 12% to 15% for the three missions at the northern Adriatic and Black Sea sites, and from 13% to -26% for the Baltic and North Sea sites. It is in the interval 16-31% for the near-infrared band. The spectral shape of tau(a) is well reproduced with a median bias of the Angstrom exponent varying between -15% and +14%, which represents a clear improvement with respect to previous versions of the atmospheric correction scheme. These results show that the uncertainty associated with tau(a) in the considered coastal waters of the European marginal seas is comparable to global validation statistics.

Keywords
Aerosols, Ocean colour, AERONET, Validation, European seas
National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-411 (URN)10.5697/oc.55-1.027 (DOI)000319843600003 ()
Available from: 2015-04-10 Created: 2015-03-31 Last updated: 2017-12-04Bibliographically approved
Toledano, C., Cachorro, V. E., Gausa, M., Stebel, K., Aaltonen, V., Berjon, A., . . . Torres, B. (2012). Overview of sun photometer measurements of aerosol properties in Scandinavia and Svalbard. Atmospheric Environment, 52, 18-28
Open this publication in new window or tab >>Overview of sun photometer measurements of aerosol properties in Scandinavia and Svalbard
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2012 (English)In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 52, p. 18-28Article in journal (Refereed) Published
Abstract [en]

An overview on the data of columnar aerosol properties measured in Northern Europe is provided. Apart from the necessary data gathered in the Arctic, the knowledge of the aerosol loading in nearby areas (e.g. sub-Arctic) is of maximum interest to achieve a correct analysis of the Arctic aerosols and transport patterns. This work evaluates data from operational sites with sun photometer measurements belonging either to national or international networks (AERONET, GAW-PFR) and programs conducted in Scandinavia and Svalbard. We enumerate a list of sites, measurement type and periods together with observed aerosol properties. An evaluation and analysis of aerosol data was carried out with a review of previous results as well. Aerosol optical depth (AOD) and Angstrom exponent (AE) are the current parameters with sufficient long-term records for a first evaluation of aerosol properties. AOD (500 nm) ranges from 0.08 to 0.10 in Arctic and sub-Arctic sites (Ny-Alesund: 0.09; Andenes: 0.10; Sodankyla: 0.08), and it is somewhat higher in more populated areas in Southern Scandinavia (AOD about 0.10-0.12 at 500 nm). On the Norwegian coast, aerosols show larger mean size (AE = 1.2 at Andenes) than in Finland, with continental climate (AE = 1.5 at Sodankyla). Columnar particle size distributions and related parameters derived from inversion of sun/sky radiances were also investigated. This work makes special emphasis in the joint and collaborative effort of the various groups from different countries involved in this study. Part of the measurements presented here were involved in the IPY projects Polar-AOD and POLARCAT. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords
Aerosol, Sun photometer, Arctic, Scandinavia
National Category
Climate Research
Research subject
Climate
Identifiers
urn:nbn:se:smhi:diva-458 (URN)10.1016/j.atmosenv.2011.10.022 (DOI)000303098500003 ()
Available from: 2015-04-20 Created: 2015-04-14 Last updated: 2017-12-04Bibliographically approved
Michalsky, J., Dutton, E. G., Nelson, D., Wendell, J., Wilcox, S., Andreas, A., . . . Halliwell, D. (2011). An Extensive Comparison of Commercial Pyrheliometers under a Wide Range of Routine Observing Conditions. Journal of Atmospheric and Oceanic Technology, 28(6), 752-766
Open this publication in new window or tab >>An Extensive Comparison of Commercial Pyrheliometers under a Wide Range of Routine Observing Conditions
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2011 (English)In: Journal of Atmospheric and Oceanic Technology, ISSN 0739-0572, E-ISSN 1520-0426, Vol. 28, no 6, p. 752-766Article in journal (Refereed) Published
Abstract [en]

In the most comprehensive pyrheliometer comparison known to date, 33 instruments were deployed to measure direct normal solar radiation over a 10-month period in Golden, Colorado. The goal was to determine their performance relative to four electrical-substitution cavity radiometers that were calibrated against the World Radiometric Reference (WRR) that is maintained at the World Radiation Center in Davos, Switzerland. Because of intermittent cabling problems with one of the cavity radiometers, the average of three windowed, electrical-substitution cavity radiometers served as the reference irradiance for 29 test instruments during the 10-month study. To keep the size of this work manageable, comparisons are limited to stable sunny conditions, passing clouds, calm and windy conditions, and hot and cold temperatures. Other variables could have been analyzed, or the conditions analyzed could have employed higher resolution. A more complete study should be possible now that the instruments are identified; note that this analysis was performed without any knowledge on the part of the analyst of the instruments' manufacturers or models. Apart from the windowed cavities that provided the best measurements, two categories of performance emerged during the comparison. All instruments exceeded expectations in that they measured with lower uncertainties than the manufacturers' own specifications. Operational 95% uncertainties for the three classes of instruments, which include the uncertainties of the open cavities used for calibration, were about 0.5%, 0.8%, and 1.4%. The open cavities that were used for calibration of all pyrheliometers have an estimated 95% uncertainty of 0.4%-0.45%, which includes the conservative estimate of 0.3% uncertainty for the WRR.

National Category
Meteorology and Atmospheric Sciences
Research subject
Remote sensing
Identifiers
urn:nbn:se:smhi:diva-520 (URN)10.1175/2010JTECHA1518.1 (DOI)000291972400002 ()
Available from: 2015-04-17 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
Carlund, T. (2011). Upgrade of SMHI's meteorological radiation network 2006-2007: Effects on direct and global solar radiation. SMHI
Open this publication in new window or tab >>Upgrade of SMHI's meteorological radiation network 2006-2007: Effects on direct and global solar radiation
2011 (English)Report (Other academic)
Abstract [sv]

SMHIs strålningsnät moderniserades 2006-2007. Innan de äldre mätningarna upphörde genomfördes parallella mätningar med både ny och gammal utrustning under 6-18 månader. Här rapporteras resultaten av jämförelsen mellan de gamla och de nya mätningarna av i huvudsak globalstrålning och direktstrålning. I genomsnitt var överensstämmelsen god mellan de gamla och de nya mätningarna. Medelvärdet av förhållandet mellan de gamla och nya mätningarna, baserat på tidsintegrerade värden från hela den tillgängliga jämförelseperioden vid respektive station, var 0,997 för globalstrålning (12 stationer) och 1,009 för direktstrålning (3 stationer). Inget av dessa resultat är signifikant skilda från 1 vid en signifikansnivå av 90 %. Trots den goda överensstämmelsen identifierades ett par systematiska skillnader mellan de gamla och de nya mätningarna. Dessa skillnader antas i huvudsak bero på skillnad i öppningsvinkel mellan gamla och nya pyrheliometrar (mäter direktstrålning) samt skillnad i den riktningsberoende responsen mellan gamla och nya pyranometrar (mäter globalstrålning). Korrektionsfunktioner för dessa systematiska skillnader har utvecklats. Dessa bör tillämpas för att korrigera de äldre mätningarna (1983-2007) för att förbättra homogeniteten i framförallt månadsvärden av strålningsdata. Vid moderniseringen av strålningsnätet genomgick även de automatiska mätningarna av solskenstid en betydande förändring. Preliminära jämförelser av solskenstid från gammal och ny mätmetod ger i nuläget svårtydda resultat. En mer detaljerad studie av solskenstidsmätningarna, baserad på minut- eller t.o.m. momentanvärden, måste därför göras i framtiden.

Abstract [en]

The radiation network of SMHI was modernized in 2006-2007. Old measurements were closed down after 6-18 months of parallel operation of new and old measurements. This study reports the results of the comparison mainly between the old and new global and direct solar radiation measurements.On average the agreement between old and new measurements was good. The network average of ratios of whole period values was for global radiation 0.997 and for direct radiation 1.009. None of these results are significantly different from one at a level of confidence of 90 %.Despite the fairly good agreement some systematic differences between the old and new measurements were found. The differences are mainly thought to be caused by a difference in the apparent directional response between the old and new pyranometers and different viewing geometries in the old and new pyrheliometers. Functions to correct old global and direct radiation have been developed. These should be used to increase the homogeneity in Swedish solar radiation data from 1983and onwards, especially for monthly data.A new measurement method and new instruments for determination of sunshine duration were introduced in the upgraded network. A more detailed study comparing sunshine duration measurements by pyrheliometers in the old network and by contrast sensors in the modernized network, probably based on 1-minute or even instantaneous data, needs to be done in the future.

Place, publisher, year, edition, pages
SMHI, 2011. p. 36
Series
Meteorology, ISSN 0283-7730 ; 148
Identifiers
urn:nbn:se:smhi:diva-2262 (URN)Meteorologi, Rapporter, Serie Meteorologi (Local ID)Meteorologi, Rapporter, Serie Meteorologi (Archive number)Meteorologi, Rapporter, Serie Meteorologi (OAI)
Available from: 2011-12-05 Created: 2016-07-08 Last updated: 2016-07-08Bibliographically approved
Carlund, T., Håkansson, B. & Land, P. (2005). Aerosol optical depth over the Baltic Sea derived from AERONET and SeaWiFS measurements. Paper presented at Workshop on Baltic Sea Remote Sensing and Bio-Optical Modelling, 2001, Stockholm, SWEDEN. International Journal of Remote Sensing, 26(2), 233-245
Open this publication in new window or tab >>Aerosol optical depth over the Baltic Sea derived from AERONET and SeaWiFS measurements
2005 (English)In: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 26, no 2, p. 233-245Article in journal (Refereed) Published
Abstract [en]

Three years of data on aerosol optical depth (tau(a)) from the Aerosol Robotic Network (AERONET) station on the island of Gotland in the Baltic Sea have been analysed and compared with Sea-viewing Wide Field of view Sensor (SeaWiFS) data. Normally, the atmosphere over Gotland could be considered as clear, with a daily median value Of tau(a) at 500 nm of about 0.08. The median value of Angstrom's wavelength exponent (alpha) for wavelengths between 440 nm and 870 nm was 1.37, indicating that the dominant aerosol is more of a continental than of a pure maritime type. SeaWiFS GAC level 2 data on tau(a) and alpha were compared to data from the ground-based AERONET station. For the 37 cases of simultaneous satellite and ground-based measurements under cloud-free skies it was found that, on average, the value of tau(a)(865 nm) from SeaWiFS was about 0.02 higher than tau(a)(870 nm) from the AERONET station. At the same time approximate tau(a)(440 nm) from SeaWiFS was about 0.03 lower than tau(a)(440 nm) of AERONET. alpha(510, 865) from SeaWiFS was, on average, 1.2 lower than alpha(500, 870) from the AERONET measurements. These results cannot explain the very frequent occurences of negative values of normalized water-leaving radiance at 412 nm and 443 nm in the SeaWiFS reprocessing #3 data.

National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-1284 (URN)10.1080/01431160410001720306 (DOI)000226804800002 ()
Conference
Workshop on Baltic Sea Remote Sensing and Bio-Optical Modelling, 2001, Stockholm, SWEDEN
Available from: 2015-06-11 Created: 2015-05-26 Last updated: 2018-01-11Bibliographically approved
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