Eos berichtet über eine neue geologische Rekonstruktionsmethode zur Ermittlung von Niederschlagsvariationen:
A New Proxy for Past Precipitation
Researchers used luminescence signals from marine sediment cores to bolster estimates of precipitation levels on land over the past 30,000 years.
To understand our rapidly changing climate, researchers often look back at how Earth’s climate has behaved in the past. Marine sediment cores, like tree rings, can provide a log of former environmental conditions, allowing scientists to infer everything from the temperature and salinity of the oceans to precipitation rates on land. Precipitation rates affect river flows and thus sediment erosion rates, which means researchers can look at ratios of marine to terrestrial materials in marine sediment cores to reconstruct past precipitation rates. But this and other existing proxies for precipitation, including examining hydrogen isotopes in plant wax compounds in cores, have limitations as they can be affected by other factors and processes. Here Mendes et al. describe a new proxy for determining past precipitation from marine sediment cores using luminescence signals from feldspar and quartz grains.
Weiterlesen auf Eos
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Die Temperaturen im nördlichen Teil Ostasien sind laut Gong et al 2019 (Geophysical Research Letters) zu mehr als 70% von Ozeanzyklen dominiert, die den Langzeittrend überstrahlen. Abstract:
Attribution of the East Asian Winter Temperature Trends During 1979–2018: Role of External Forcing and Internal Variability
Attributing the surface air temperature (SAT) trends at regional scale to internally generated and externally forced components is a major challenge. Based on the observations and ensemble simulations of climate models, we apply a “dynamical adjustment” methodology to estimate quantitatively the contribution of the internal and forced dynamic and thermodynamic components to the East Asian winter SAT trends during 1979–2018. The observed winter SAT trends are strongly influenced by internal variability, especially in the northern East Asia (NEA). The internal component of observed SAT trends is largely dynamically induced, whereas the forced component is controlled by thermodynamics. The internally generated variability offsets the forced warming by more than 70% in the NEA, leading to a weak observed warming in the NEA. In contrast, internal contributions are small in the southern East Asia. The internally generated SAT changes in the NEA are closely tied to the multidecadal changes of Arctic Oscillation.
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Playbuzz mit einem Klimawandelquiz (erstellt von der GWPF):
The Big Climate Change Quiz
You are terrified about climate change! So you have joined millions around the world for Greta’s school strike for the climate. This is not anything to do with skipping lessons of course, you feel passionately. But have you got your facts straight? Time to find out…
Wenn Sie des Englischen mächtig sind, machen Sie auf jeden Fall mit. Der eine oder andere Klimaaktivist wird beim Ausfüllen des Onlinefragebogens mächtig gestaunt haben… Hier gehts los.
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The Province im September 2019:
GOLDSTEIN: Feds scrapped 100 years of data on climate change
Canadians already suspicious of Prime Minister Justin Trudeau’s carbon tax are likely be even more suspicious given a report by Ottawa-based Blacklock’s Reporter that Environment Canada omitted a century’s worth of observed weather data in developing its computer models on the impacts of climate change.
The scrapping of all observed weather data from 1850 to 1949 was necessary, a spokesman for Environment Canada told Blacklock’s Reporter, after researchers concluded that historically, there weren’t enough weather stations to create a reliable data set for that 100-year period.
“The historical data is not observed historical data,” the spokesman said. “It is modelled historical data … 24 models from historical simulations spanning 1950 to 2005 were used.”
Weiterlesen bei The Province
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Handelsblatt im September 2019:
Klimawandel: Mehr als 500 Großinvestoren fordern, CO2-Preis drastisch zu erhöhen
In einem gemeinsamen Statement appellieren institutionelle Investoren vor dem globalen Klimastreik für mehr Maßnahmen gegen den Treibhauseffekt.
Joachim Wenning ist kein Hitzkopf. Doch beim Thema Klimawandel zeigt der Vorstandschef des Rückversicherers Munich Re eine ungewohnte Härte. Öffentlich fordert der Topmanager seit Monaten, den Preis für den Ausstoß von CO2 drastisch zu verteuern. Genauer gesagt: fast zu verfünffachen. Andernfalls würden sich die Folgen des Klimawandels noch dramatisch verschärfen, so Wennings Warnung.
Sind dies Großinvestoren, die sich durch diese Forderung Vorteile versprechen? Die MunichRe ist seit langem dafür bekannt, dass sie die Klimaangst befördert. Lesen Sie die folgenden Blogartikel und schmunzeln Sie:
Zahl der Naturkatastrophen sinkt 2013 auf Zehn-Jahres-Tief
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Business Insider im September 2019:
Immer mehr Jugendliche schwören sich, keine Kinder zu bekommen, solange Regierungen nichts gegen den Klimawandel tun
Vielleicht eine gute Maßnahme gegen unerwünschte Teenagerschwangerschaften…
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Was steckt hinter dem 11-jährigen Sonnenfleckenzyklus? Pressemitteilung der University of Washington aus dem September 2019:
Plasma flow near sun’s surface explains sunspots, other solar phenomena
For 400 years people have tracked sunspots, the dark patches that appear for weeks at a time on the sun’s surface. They have observed but been unable to explain why the number of spots peaks every 11 years. A University of Washington study published this month in the journal Physics of Plasmas proposes a model of plasma motion that would explain the 11-year sunspot cycle and several other previously mysterious properties of the sun. „Our model is completely different from a normal picture of the sun,“ said first author Thomas Jarboe, a UW professor of aeronautics and astronautics. „I really think we’re the first people that are telling you the nature and source of solar magnetic phenomena — how the sun works.“
The authors created a model based on their previous work with fusion energy research. The model shows that a thin layer beneath the sun’s surface is key to many of the features we see from Earth, like sunspots, magnetic reversals and solar flow, and is backed up by comparisons with observations of the sun. „The observational data are key to confirming our picture of how the sun functions,“ Jarboe said.
In the new model, a thin layer of magnetic flux and plasma, or free-floating electrons, moves at different speeds on different parts of the sun. The difference in speed between the flows creates twists of magnetism, known as magnetic helicity, that are similar to what happens in some fusion reactor concepts. „Every 11 years, the sun grows this layer until it’s too big to be stable, and then it sloughs off,“ Jarboe said. Its departure exposes the lower layer of plasma moving in the opposite direction with a flipped magnetic field.
When the circuits in both hemispheres are moving at the same speed, more sunspots appear. When the circuits are different speeds, there is less sunspot activity. That mismatch, Jarboe says, may have happened during the decades of little sunspot activity known as the „Maunder Minimum.“ „If the two hemispheres rotate at different speeds, then the sunspots near the equator won’t match up, and the whole thing will die,“ Jarboe said.
„Scientists had thought that a sunspot was generated down at 30 percent of the depth of the sun, and then came up in a twisted rope of plasma that pops out,“ Jarboe said. Instead, his model shows that the sunspots are in the „supergranules“ that form within the thin, subsurface layer of plasma that the study calculates to be roughly 100 to 300 miles (150 to 450 kilometers) thick, or a fraction of the sun’s 430,000-mile radius. „The sunspot is an amazing thing. There’s nothing there, and then all of a sudden, you see it in a flash,“ Jarboe said.
The group’s previous research has focused on fusion power reactors, which use very high temperatures similar to those inside the sun to separate hydrogen nuclei from their electrons. In both the sun and in fusion reactors the nuclei of two hydrogen atoms fuse together, releasing huge amounts of energy.
The type of reactor Jarboe has focused on, a spheromak, contains the electron plasma within a sphere that causes it to self-organize into certain patterns. When Jarboe began to consider the sun, he saw similarities, and created a model for what might be happening in the celestial body. „For 100 years people have been researching this,“ Jarboe said. „Many of the features we’re seeing are below the resolution of the models, so we can only find them in calculations.“
Other properties explained by the theory, he said, include flow inside the sun, the twisting action that leads to sunspots and the total magnetic structure of the sun. The paper is likely to provoke intense discussion, Jarboe said. „My hope is that scientists will look at their data in a new light, and the researchers who worked their whole lives to gather that data will have a new tool to understand what it all means,“ he said.
The research was funded by the U.S. Department of Energy. Co-authors are UW graduate students Thomas Benedett, Christopher Everson, Christopher Hansen, Derek Sutherland, James Penna, UW postdoctoral researchers Aaron Hossack and John Benjamin O’Bryan, UW affiliate faculty member Brian Nelson, and Kyle Morgan, a former UW graduate student now at CTFusion in Seattle.
Paper: T. R. Jarboe, T. E. Benedett, C. J. Everson, C. J. Hansen, A. C. Hossack, K. D. Morgan, B. A. Nelson, J. B. O’Bryan, J. M. Penna, D. A. Sutherland. The nature and source of solar magnetic phenomena. Physics of Plasmas, 2019; 26 (9): 092902 DOI: 10.1063/1.5087613
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Die NOAA bietet Graphiken für monatliche Temperaturen und Niederschläge für globale und US-Werte. Hier ausprobieren.
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Hier etwas für unsere Physiker unter den Lesern: Ghil & Lucarini 2019 (großes pdf hier). Abstract:
The Physics of Climate Variability and Climate Change
The climate system is a forced, dissipative, nonlinear, complex and heterogeneous system that is out of thermodynamic equilibrium. The system exhibits natural variability onmany scales of motion, in time as well as space, and it is subject to various external forcings, natural as well as anthropogenic. This paper reviews the observational evidence on climate phenomena and the governing equations of planetary-scale flow, as well as presenting the key concept of a hierarchy of models as used in the climate sciences. Recent advances in the application of dynamical systems theory, on the one hand, and of nonequilibrium statistical physics, on the other, are brought together for the first timeand shown to complement each other in helping understand and predict the system’s behavior. These complementary points of view permit a self-consistent handling of subgrid-scale phenomena as stochastic processes, as well as a unified handling of natural climate variability and forced climate change, along with a treatment of the crucial issues of climate sensitivity, response, and predictability.
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