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A European Lake Surface Water Temperature data set derived from NOAA/Metop-AVHRR (1983 - 2013) - a proxy for climate change

Applicant Wunderle Stefan
Number 146740
Funding scheme Project funding (Div. I-III)
Research institution Geographisches Institut Universität Bern
Institution of higher education University of Berne - BE
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.10.2013 - 30.11.2016
Approved amount 185'650.00
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All Disciplines (3)

Discipline
Climatology. Atmospherical Chemistry, Aeronomy
Hydrology, Limnology, Glaciology
Other disciplines of Environmental Sciences

Keywords (6)

Limnology; Lake surface water temperature; time series; climate change; NOAA/MetOp-AVHRR; split-window

Lay Summary (German)

Lead
Aus unserem umfangreichen Archiv an Satellitendaten, werden die Oberflächentemperaturen von den grössten europäischen Seen von 1985 - 2013 abgeleitet. Im Rahmen des geförderten Projektes wird das Klimasignal aus den Seeoberflächentemperturen analysiert und in Beziehung gesetzt zu Veränderungen der Lufttemperatur und Globalstrahlung/Bewölkung. Erstmals wird eine homogener Datensatz erzeugt, der sich vom Nordkap bis Mittelmeer erstreckt.
Lay summary
Seen nehmen eine wichtige Rolle in unserem Leben ein. Zum einen sind sie Frischwasserreservoir und wichtig für den Tourismus als Naherholungsziele, zum anderen sind Seen ein wichtiger Lebensraum und beeinflussen auch das lokale Klima. Im Rahmen des Projektes wird aus Satellitendaten die Oberflächentemperatur von allen grösseren Seen in Europa von 1985 - 2013 abgeleitet. Verschiedene wissenschaftliche Arbeiten weissen darauf hin, dass sich die Temperatur von Seen stärker erwärmt hat, als die umliegende Lufttemperatur. Mit der neuen Temperaturreihe, die wir aus unserem umfangreichen Archiv von AVHRR-Satellitendaten berechnen, können wir einen wichtigen Beitrag zu dieser Fragestellung liefern. Weiterhin wird es erstmalig einen homogenen Datensatz geben, der von Nordnorwegen bis Griechenland sehr unterschiedliche klimatische Zonen einschliesst.Wir sind gespannt, ob sich das Klimasignal in gleichem Masse für unterschiedliche Klimazonen in Europa abbildet. Zum Ende des Projektes werden die Daten für interessierte Wissenschaftler frei zur Verfügung stehen und können auch einen Beitrag zur Klimamodellierung liefern. 
Direct link to Lay Summary Last update: 16.07.2013

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
Dr. Gabriela Seiz, GCOS-Meteoschweiz Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
AGU fall meeting Talk given at a conference Lake Surface Water Temperature of European lakes derived from AVHRR data - time series and quality assessment 12.12.2016 San Francisco, United States of America Riffler Michael; Wunderle Stefan; Lieberherr Gian;
European Geoscience Union EGU Poster Performance comparison of Landsat 8 TIRS and NOAA/METOP AVHRR-3 for lake surface water temperature retrieval 17.04.2016 Vienna, Austria Wunderle Stefan; Lieberherr Gian;
13th Swiss Geoscience Meeting, Basel Talk given at a conference Lake Surface Water Temperature: Performance of split-window coefficients – a sensitivity analysis 20.11.2015 Basel, Switzerland Lieberherr Gian; Wunderle Stefan;
3rd GlobTemperature User Consultation Meeting Talk given at a conference European Lake Surface Water Temperature:Performance assessment and validity restrictions of split-window coefficients 15.06.2015 Reading, Great Britain and Northern Ireland Riffler Michael; Lieberherr Gian; Wunderle Stefan;
13th International Swiss Climate Summer School Poster A European Lake Surface Water Temperature data set derived from NOAA/Metop-AVHRR (1983–2013) 31.08.2014 Grindelwald, Switzerland Wunderle Stefan; Riffler Michael; Lieberherr Gian;
ESA LPVE conference Talk given at a conference Lake Surface Water Temperature retrieval - a contribution for a LST data set 11.02.2014 Frascati, Italy Wunderle Stefan; Riffler Michael;


Abstract

More than 2/3 of the Earth's surface is covered by water. This influences not only our daily life but also the climate and the dynamics of the weather. Evaporation from ocean and lake surfaces is the main driver of the atmospheric water cycle. The heat balance of lakes is determined primarily by three radiative and two non-radiative heat exchange processes, four of which respond directly to changes in atmospheric forcing. Based on in-situ measurements conducted during the last few decades, almost all European lakes show a long-term increase in temperature at all depths, but most markedly in the surface mixed layer. In addition, the duration of ice cover on high-latitude and high-altitude lakes has decreased. Hence, lake water temperature is a promising proxy for the study of climatic change in Europe. However, much of the available information is based on in-situ measurements, which are sparse, have temporal gaps, were made at different depths and are sometimes available only for a short period.Satellite data will be used to compile a homogeneous and consistent time series of lake surface water temperature (LSWT - skin temperature) for the whole of Europe. A modified split-window approach with locally adapted split-window coefficients will be applied to retrieve LSWT with high accuracy. A skin-bulk conversion will be implemented to make the satellite data comparable with in-situ measurements. To minimize scatter and bias a careful post-processing will be added to remove erroneous pixels (e.g. sub-pixel clouds). Validation of the satellite-retrieved LSWT data will ensure that their quality is sufficiently high for statistical time series analysis.The principal item of the proposed project is the processing and statistical analysis of LSWT, which will bring new insights on temperature changes in European lakes during the last 30 years. The project focuses on the retrieval of LWST based on our archived satellite data of the NOAA-/MetOp series, and aims at addressing the following scientific questions:•Has LSWT in Europe changed significantly during the last 30 years?•Is there a difference between nighttime and daytime LSWT?•Are the changes related to latitude (north-south gradient)?•The rate of increase of LSWT in some lakes is known to exceed that of the ambient air temperature. What is driving this?A homogenous and consistent LSWT data set with a high resolution both spatially (1.1 km2) and temporally (daily, but depends on cloud cover) based on data from the Advanced Very High Resolution Radiometer (AVHRR) on board the NOAA-/MetOp-satellites will be generated. For the first time, this will allow changes in LSWT for a large suite of European lakes at many different elevations and latitudes to be analysed with respect to trend and variability. The analysis will take into account air temperature, cloud cover and atmospheric water vapour. Finally, the LWST dataset will be made available to limnologists, hydrologists, and the climate modelling community. The significance of this project is:- to show for the first time the spatial and temporal distribution of LSWT during the last 30 years for many European lakes.- to contribute to international networks (e.g. COST Action ES1201 "Netlake" (http://www.cost.eu/domains_actions/essem/Actions/ES1201; Global Lake Temperature Collaboration GLTC: http://snr.unl.edu/GLTC/index.html; Global Lake Ecological Observatory Network GLEON: http://www.gleon.org)
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