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Towards an improved understanding of the Global Energy Balance: temporal variation of solar radiation in the climate system

Applicant Wild Martin
Number 159938
Funding scheme Project funding (Div. I-III)
Research institution Institut für Atmosphäre und Klima ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.01.2016 - 30.06.2019
Approved amount 184'507.00
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Keywords (6)

Solar radiation; Surface Albedo; Climate Change; Global Energy Balance ; Radiation Budget; Global Dimming

Lay Summary (German)

Lead
Die Sonne bildet die fundamentale Energiequelle für das Klimasystem, und ist von zentraler Bedeutung für die Energiebilanz der Erde. Veränderungen in der Menge der absorbierten Sonnenenergie im Klimasystem haben deshalb einen grossen Einfluss auf vierschiedenste Aspekte des Kimawandels, nicht nur auf die Erderwärmung, sondern zum Beispiel auch auf die Intensität des Wasserkreislaufs, Schnee- und Gletscherschmelze, Pflanzenwachstum und Kohlenstoffkreislauf, sowie auch auf die Erzeugung von Solarstrohm. Trotz deren Bedeutung ist unser Wissen bezüglich Veränderungen in der absorbierten Sonnenenergie innerhalb des Klimasystems sehr limitiert. Das Ziel des vorliegenden Projektes ist es, diese Veränderungen besser zu verstehen und zu quantifizieren. Dazu verwenden wir Beobachtungen, die sowohl von der Erdoberfläche als auch von Satelliten aus gemacht werden.
Lay summary
Das Klima auf der Erde wird wesentlich geprägt durch die Bilanz zwischen absorbierter Sonnenenergie und der von der Erde emittierten thermischen Energie, der sogenannten Energiebilanz. Der Eingriff des Menschen ins Klimasystem erfolgt in erster Linie durch eine Störung dieser Energiebilanz, insbesondere durch Veränderungen der Konzentrationen von Treibhausgasen und Staubpartikeln in der Atmosphäre. Trotz der zentralen Bedeutung der globalen Energiebilanz für das Klimasystems und den Klimawandel bestehen immer noch grosse Unsicherheiten in der Quantifizierung ihrer Komponenten und deren Veränderung über die Zeit.
Das langfristige übergeordnete Ziel unserer Untersuchungen ist darum ein verbessertes Verständnis der globalen Energiebilanz und deren raumzeitlichen Veränderungen. Während wir dank neuer Satellitenmessysteme mittlerweile wesentlich mehr wissen über den Energieaustausch zwischen dem Klimasystem und dem Weltraum, kennen wir die Verteilung der Strahlungsenergie innerhalb des Klimasystems, die nicht direkt von den Satelliten gemessen werden kann, nur ungenügend. Unser Ziel ist es deshalb, die Unsicherheiten in der Absorption der Solarstrahlung innerhalb des Klimasystems, einer wesentlichen Komponente der Energiebilanz, zu reduzieren. Dies erreichen wir durch eine Kombination von weltweiten Messungen von der Erdoberfläche und von Satelliten aus. Während das NFP Vorgängerprojekt 200021_135395 die Abschätzung der klimatologischen mittleren Absorption zum Ziel hatte, liegt das Schwergewicht des gegenwärtigen Nachfolgeprojekts auf der zeitlichen Variation der  Absorption, die für das Verständnis des Klimawandel  unerlässlich ist. Der Untersuchungszeitraum liegt schwergewichtig auf der Periode nach 2000, da ab diesem Zeitpunkt zuverlässige Satellitendaten vorhanden sind.  Zudem beinhaltet diese Periode auch einen Stillstand der Erderwärmung (“hiatus”), zu dessem Verständnis eine genaue Analyse der Veränderungen der Energieflüsse beitragen kann.
Direct link to Lay Summary Last update: 11.11.2015

Lay Summary (English)

Lead
Solar radiation is the fundamental energy source for the climate system, and a central component of the Global Energy Balance. Variations in the amount of solar radiation absorbed in the climate system have therefore a profound impact on various aspects of climate change, and on a more applied level, on the generation of solar power. Despite its importance, our knowledge on changes in solar absorption in the climate system is still very limited. In the present project we aim at better quantifying these changes using the information contained in both surface and space-based observation systems.
Lay summary

The genesis and evolution of Earth’s climate is largely regulated by the balance between inflow of solar energy (received from the Sun) and outflow of thermal energy (emitted by the Earth). Human interference with climate occurs first of all through a perturbation of this energy balance, as a result of anthropogenic modification of greenhouse gas and aerosol concentration. Changes in the global energy balance affect not only global warming, but also other aspects of climate change, such as the intensity of the water cycle, snow cover and glacier retreat, plant productivity and terrestrial carbon uptake. Despite the central importance of the global energy balance for the climate system and climate change, substantial uncertainties still exist in the quantification of its different components and their decadal variations. The long-term research goal of the investigators aims at an improved understanding of the mean state and the spatio-temporal variations of the global energy balance. While our knowledge on the energy exchange between Sun, Earth and space has recently been improved through new satellite programs, the distribution of radiative energy within the climate system, which cannot directly be measured by satellites, is still afflicted with large uncertainties. Our aim is therefore to reduce the uncertainties in the absorption of solar radiation within the climate system, a crucial component of the global energy balance, through an optimal usage of the information contained in worldwide surface and satellite measurements. While the predecessor SNF project 200021_135395 aimed at the estimation of the climatological mean solar absorption in the climate system, the present follow up project focuses on its temporal variation, which is crucial for the understanding of global climate change. The focus is on the period after 2000, where adequate satellite observations started to become available, and which states a particularly interesting period covering the global warming hiatus.

 

Direct link to Lay Summary Last update: 11.11.2015

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
The cloud-free global energy balance and inferred cloud radiative effects: an assessment based on direct observations and climate models
Wild Martin, Hakuba Maria Z., Folini Doris, Dörig-Ott Patricia, Schär Christoph, Kato Seiji, Long Charles N. (2019), The cloud-free global energy balance and inferred cloud radiative effects: an assessment based on direct observations and climate models, in Climate Dynamics, 52(7-8), 4787-4812.
From Point to Area: Worldwide Assessment of the Representativeness of Monthly Surface Solar Radiation Records
Schwarz M., Folini D., Hakuba M. Z., Wild M. (2018), From Point to Area: Worldwide Assessment of the Representativeness of Monthly Surface Solar Radiation Records, in Journal of Geophysical Research: Atmospheres, 123(24), 13,857-13,874.
Spatial Representativeness of Surface-Measured Variations of Downward Solar RadiationSPATIOTEMPORAL REPRESENTATIVENESS OF SSR
Schwarz M., Folini D., Hakuba M. Z., Wild M. (2017), Spatial Representativeness of Surface-Measured Variations of Downward Solar RadiationSPATIOTEMPORAL REPRESENTATIVENESS OF SSR, in Journal of Geophysical Research: Atmospheres, 122(24), 13,319-13,337.
Urbanization effect on trends in sunshine duration in China
Wang Yawen, Wild Martin, Sanchez-Lorenzo Arturo, Manara Veronica (2017), Urbanization effect on trends in sunshine duration in China, in Annales Geophysicae, 35(4), 839-851.
Sunshine duration and global radiation trends in Italy (1959-2013): To what extent do they agree? To What Extent Do SD and Eg↓ Agree?
Manara V., Brunetti M., Maugeri M., Sanchez-Lorenzo A., Wild M. (2017), Sunshine duration and global radiation trends in Italy (1959-2013): To what extent do they agree? To What Extent Do SD and Eg↓ Agree?, in Journal of Geophysical Research: Atmospheres, 122(8), 4312-4331.
Towards Global Estimates of the Surface Energy Budget
Wild Martin (2017), Towards Global Estimates of the Surface Energy Budget, in Current Climate Change Reports, 3(1), 87-97.
Trends in downward surface solar radiation from satellites and ground observations over Europe during 1983–2010
Sanchez-Lorenzo Arturo, Enriquez-Alonso Aaron, Wild Martin, Trentmann Jörg, Vicente-Serrano Sergio M., Sanchez-Romero Alejandro, Posselt Rebekka, Hakuba Maria Z. (2017), Trends in downward surface solar radiation from satellites and ground observations over Europe during 1983–2010, in Remote Sensing of Environment, 189, 108-117.
The annual cycle of fractional atmospheric shortwave absorption in observations and models: spatial structure, magnitude and timing
MatthiasSchwarz, DorisFolini, DorisF, SuYang, MartinWild, The annual cycle of fractional atmospheric shortwave absorption in observations and models: spatial structure, magnitude and timing, in Journal of Climate.

Collaboration

Group / person Country
Types of collaboration
NASA Langley (Drs. P. Stackhouse, N. Loeb) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO, (Dr. Maria Hakuba) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
International Radiation Commission (IRC) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Department of Atmospheric Sciences, University of North Dakota (Prof. X. Dong) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
China Meteorological Administration (Dr. Yang Su) China (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Pyrenean Ecology Institute, Spanish National Research Council (Dr. Arturo Sanchez-Lorenzo) Spain (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Department of Meteorology / University of Reading (Dr. Richard P. Allan) Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Fraunhofer Insitute for Solar Energy Systems ISE (Drs. C. Schill, B. Müller) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
German Weather Service DWD (Dr. J. Trentmann) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
European Geosciences Union General Assembly 2019 Talk given at a conference nferring the contribution of changes in shortwave atmospheric absorption to dimming and brightening from colocated surface and TOA observations in Europe and China 07.04.2019 Vienna, Austria Folini Doris; Schwarz Matthias; Wild Martin;
BSRN Scientific Review and Workshop 2019 Talk given at a conference From Point to Area: Worldwide Representativeness of Monthly Surface Solar Radiation Records 16.07.2018 Boulder, Colorado, United States of America Folini Doris; Schwarz Matthias; Wild Martin;
From Point to Area: Worldwide Representativeness of Monthly Surface Solar Radiation Records Talk given at a conference 15th Conference on Cloud Physics/15th Conference on Atmospheric Radiation 08.07.2018 Vancouver, BC, Canada Schaer Christoph; Wild Martin; Schwarz Matthias;
15th Conference on Cloud Physics/15th Conference on Atmospheric Radiation of the American Meteorological Society Poster Towards Observation-Based Time Series for the Partitioning of Solar Energy in the Climate Systemat 08.07.2018 Vancouver, BC, Canada Schwarz Matthias; Wild Martin; Folini Doris;
European Geosciences Union General Assembly 2017 Talk given at a conference Spatiotemporal Representativeness of Surface-measured Variations in Downward Solar Radiation: Spatial Correlations, Biases and Errors 08.04.2018 Vienna, Austria Folini Doris; Wild Martin; Schwarz Matthias;
European Geosciences Union General Assembly 2017 Poster Towards Observation-Based Time Series for the Partitioning of Solar Energy in the Climate System 08.04.2018 Vienna, Austria Folini Doris; Wild Martin; Schwarz Matthias;
European Geosciences Union General Assembly 2017 Poster Spatio-temporal representativeness of ground-based downward solar radiation measurements 23.04.2017 Vienna, Austria Folini Doris; Schwarz Matthias; Wild Martin;
Radiation Budget Workshop 2016 Poster Spatio-Temporal Representativeness of Ground-Based Downward Solar Radiation Measurements 18.10.2016 Reading, Great Britain and Northern Ireland Schwarz Matthias; Folini Doris; Wild Martin;


Communication with the public

Communication Title Media Place Year
New media (web, blogs, podcasts, news feeds etc.) Riskanter Plan zur Rettung der Welt ORF online International 2019

Awards

Title Year
Outstanding Student Poster Award 15th Conference on Cloud Physics/15th Conference on Atmospheric Radiationof the American Meteorological Society in Vancouver, Canada 2018

Associated projects

Number Title Start Funding scheme
135395 Towards an improved understanding of the Global Energy Balance: absorption of solar radiation 01.01.2012 Project funding (Div. I-III)
135395 Towards an improved understanding of the Global Energy Balance: absorption of solar radiation 01.01.2012 Project funding (Div. I-III)
178753 Arctic Tundra Surface Energy Budget - assessing the status and informing predictions 01.12.2018 Project funding (Div. I-III)
188601 Towards an improved understanding of the Global Energy Balance: causes of decadal changes of solar radiation 01.09.2020 Project funding (Div. I-III)

Abstract

Solar radiation is the fundamental energy source for the climate system, and a central component of the Global Energy Balance. Longterm observational records at worldwide radiation stations show substantial multidecadal variations in the amount of solar radiation reaching the Earth’s surface. These variations have a profound impact on various environmental issues such as global warming, glacier retreat, the strength of the global water cycle or also, on a more applied level, on agricultural production and on the rapidly growing market of solar energy generation. The variations in solar radiation reaching the Earth’s surface are much larger than variations in the solar input to the climate system, and therefore have to be due to processes internal to the climate system. To date it is debated, however, whether these variations are caused primarily by processes which reflect solar radiation back to space, such as through scattering aerosols or cloud reflection, or rather by absorptive processes, such as absorbing aerosols and cloud absorption, which have opposing impacts on global warming. A promising way to address these questions is to combine surface radiation measurements with collocated measurements of solar reflection back to space from satellites, which allows an estimation of the disposition of solar radiation in the climate system and attribution to absorption and scattering. In a previous PhD Project approved by SNF in 2011 (hereafter referred to as SNF2011), such a combined dataset of collocated surface and space-born observations has been established and applied to estimate the climatological mean absorption of solar radiation in the climate system. In this complementary follow-up proposal, this unique dataset will be extended to near present, to study the temporal variation of solar radiation in the climate system. While many of the surface radiation records span several decades back in time, adequate space born measurements began in the year 2000 with the establishment of new comprehensive satellite programs. Therefore, combined datasets of surface and space born observations can soon be established for a period exceeding 15 years, reaching a stage where temporal variability can be studied. This dataset will thus allow an unprecedented quantification of the variations in the disposition of solar radiation in the climate system, which is crucial for the understanding of climate variability since the turn of the millennium. The study period since 2000 is particularly interesting as it covers a phase where global temperatures have not been rising (“global warming hiatus”). It is therefore crucial to improve our knowledge on how the energy fluxes varied during this period. The proposed project further addresses methodological issues related to the temporal variation of solar radiation, such as the representativeness of changes measured at an observation station for a larger area, or an assessment of the influence of interannual variability on the estimated statistical parameters.
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