Seminars for Scientists

It is essential to maintain global measurements of the Earth’s Radiation Budget (ERB) from space, which are the scattered solar and emitted thermal radiative fluxes leaving the planet. These are required for purposes of validating current climate model predictions of our planet’s future response to anthropogenic greenhouse gas forcing. The measurement accuracy and calibration stability… Read more »

”Self-organising plasmas” – or “complex plasmas” consist of electrons, ions and charged microparticles. The charged microparticles can be visualised individually, allowing full kinetic access to the plasma distribution function for the first time. Complex plasmas can self-organise spontaneously to assume liquid and even crystalline states – these are new states of “soft matter”, which were… Read more »

The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 1:26:03 PDT on April 25, 2007 becoming the first satellite mission dedicated to the study of noctilucent clouds. A Pegasus XL rocket launched the satellite into a near perfect 600 km, noon – midnight, sun synchronous… Read more »

Following the New Horizons’ encounter with Jupiter, there has been a flurry of debate in the literature regarding the fundamental nature of Jupiter’s magnetosphere. The observation of large plasmoids filling Jupiter’s magnetotail prompted the suggestion by McComas and Bagenal [2007] that Jupiter has “a fundamentally different interaction with the solar wind”. At Earth, there is… Read more »

Monitoring perturbations in the long-term balance between Earth’s absorption of radiative energy from the Sun and its emission of infrared radiation to space is one of the primary objectives behind the Decadal Survey Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Through on-orbit traceability of measurements to SI standards, CLARREO will initiate benchmark climate data… Read more »

In situ measurements of total and gas phase water as well as ice crystals have been obtained during several airborne field experiments in the Arctic, at midlatitudes and in the tropics. From the data set obtained in these experiments, the ice water content (IWC) in cirrus clouds is derived as a function of temperature for… Read more »

The recent verification that small asteroids are rubble piles and are subject the YORP effect (i.e, that solar radiation pressure makes asteroid spin rates change over relatively short time spans) has wide-ranging consequences for the life cycles of these bodies. As the spin rate of an asteroid changes, its minimum energy configuration can change and… Read more »

The motion of thermal ions is surprisingly unresolved at Saturn. Due to Saturn’s strong magnetic field it is expected that plasma close to planet will co-rotate with the magnetic field, but where does this break down? The two Voyager fly-bys suggest this happens around 6 Saturn radii from the planet, although the passes were non-… Read more »

Recent satellite measurements have enabled discovery of a recurrent ‘breathing’, or expansion and contraction, of the Earth’s upper atmosphere at periods of several days. Evidence of this ‘breathing’ is found in upper atmospheric density, composition, and in gases responsible for cooling the upper atmosphere. The discovery of multi-day periodicities in the upper atmosphere is shown… Read more »

The AIM (Aeronomy of Ice in the Mesosphere) spacecraft was launched on 25 April 2007. AIM is currently producing all planned observations. Some days after launch, however, AIM began to exhibit a problem in which it would not always achieve proper receiver uplink communications lock. During several periods from May 2007 to present there have… Read more »

NASA and the German Space Agency launched the GRACE satellite gravity mission in 2002. The mission is projected to last through 2013. GRACE provides highly accurate solutions for the Earth’s global gravity field every month. Differences between fields for different months provide information about time-variability in the gravity field, and so about month-to-month fluctuations in… Read more »

The simple molecular ion H3+ has been known in the laboratory since 1911, when it was discovered by JJ Thomson while carrying out experiments on “rays of positive electricity”. It is stable, but highly reactive, making it an initiator chemical changes in mixed gases such as planetary atmospheres and the interstellar medium. The enormous anharmonicity… Read more »

During MESSENGER’s second flyby of Mercury on October 6, 2008, very intense reconnection was observed between the planet’s magnetic field and a steady southward interplanetary magnetic field (IMF). The dawn magnetopause was threaded by a strong magnetic field normal to its surface, ~ 14 nT, that implies a rate of reconnection ~10 times the typical… Read more »

Both spectral and spatial resolution of space- and airborne radiometers have increased tremendously over the last two decades. At the same time, climate, cloud, and radiative transfer models became considerably more accurate due to growing computing capabilities. The question arises: How much resolution and accuracy is needed for which application? In this context, “prioritization” of… Read more »

“Self-organising plasmas” – or “complex plasmas” consist of electrons, ions and charged microparticles. The charged microparticles can be visualised individually, allowing full kinetic access to the plasma distribution function for the first time. Complex plasmas can self-organise spontaneously to assume liquid and even crystalline states – these are new states of “soft matter”, which were… Read more »

Abstract: The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 1:26:03 PDT on April 25, 2007 becoming the first satellite mission dedicated to the study of noctilucent clouds. A Pegasus XL rocket launched the satellite into a near perfect 600 km, noon – midnight, sun… Read more »

Following the New Horizons’ encounter with Jupiter, there has been a flurry of debate in the literature regarding the fundamental nature of Jupiter’s magnetosphere. The observation of large plasmoids filling Jupiter’s magnetotail prompted the suggestion by McComas and Bagenal [2007] that Jupiter has “a fundamentally different interaction with the solar wind”. At Earth, there is… Read more »

Monitoring perturbations in the long-term balance between Earth’s absorption of radiative energy from the Sun and its emission of infrared radiation to space is one of the primary objectives behind the Decadal Survey Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Through on-orbit traceability of measurements to SI standards, CLARREO will initiate benchmark climate data… Read more »

In situ measurements of total and gas phase water as well as ice crystals have been obtained during several airborne field experiments in the Arctic, at midlatitudes and in the tropics. From the data set obtained in these experiments, the ice water content (IWC) in cirrus clouds is derived as a function of temperature for… Read more »

The recent verification that small asteroids are rubble piles and are subject the YORP effect (i.e, that solar radiation pressure makes asteroid spin rates change over relatively short time spans) has wide-ranging consequences for the life cycles of these bodies. As the spin rate of an asteroid changes, its minimum energy configuration can change and… Read more »

The motion of thermal ions is surprisingly unresolved at Saturn. Due to Saturn’s strong magnetic field it is expected that plasma close to planet will co-rotate with the magnetic field, but where does this break down? The two Voyager fly-bys suggest this happens around 6 Saturn radii from the planet, although the passes were non-… Read more »

Recent satellite measurements have enabled discovery of a recurrent ‘breathing’, or expansion and contraction, of the Earth’s upper atmosphere at periods of several days. Evidence of this ‘breathing’ is found in upper atmospheric density, composition, and in gases responsible for cooling the upper atmosphere. The discovery of multi-day periodicities in the upper atmosphere is shown… Read more »

The AIM (Aeronomy of Ice in the Mesosphere) spacecraft was launched on 25 April 2007. AIM is currently producing all planned observations. Some days after launch, however, AIM began to exhibit a problem in which it would not always achieve proper receiver uplink communications lock. During several periods from May 2007 to present there have… Read more »

The simple molecular ion H3+ has been known in the laboratory since 1911, when it was discovered by JJ Thomson while carrying out experiments on “rays of positive electricity”. It is stable, but highly reactive, making it an initiator chemical changes in mixed gases such as planetary atmospheres and the interstellar medium. The enormous anharmonicity… Read more »

During MESSENGER’s second flyby of Mercury on October 6, 2008, very intense reconnection was observed between the planet’s magnetic field and a steady southward interplanetary magnetic field (IMF). The dawn magnetopause was threaded by a strong magnetic field normal to its surface, ~ 14 nT, that implies a rate of reconnection ~10 times the typical… Read more »

Both spectral and spatial resolution of space- and airborne radiometers have increased tremendously over the last two decades. At the same time, climate, cloud, and radiative transfer models became considerably more accurate due to growing computing capabilities. The question arises: How much resolution and accuracy is needed for which application? In this context, “prioritization” of… Read more »