Ion Outflow: what we have learned from Earth and how Mars is different

Abstract:
The ion outflow at Earth is driven by the Sun and the solar wind. The ions are accelerated in multiple steps. This chain driving of the ion outflow at the polar regions will be described based on aurora missions such as Freja, FAST, and DMSP. The ion outflow at Mars is also driven by the Sun and the solar wind. However, it is expected that the system is more directly driven with fewer steps. The presented ion outflow work at Mars focuses on what limits this ion outflow. The result from the Mars studies will be compared with measurements in the upcoming Mars mission

Precision photometric imaging of the Sun:  What have we learned with
the PSPT?

The Precision Solar Photometric Telescope was designed for
photometric imaging of the Sun with the aim of achieving an
unprecedented 0.1% pixel-to-pixel relative precision.  That precision has been achieved not only by careful telescope design, but by application of post processing techniques that can both recover spatial variations in detector gain to an equivalent accuracy and sensibly evaluate image distortions and the solar center-to-limb variation.   This talk will briefly review those techniques and their application, in light of recent, not so recent, and future photometric studies at the limits of the instrument's capabilities:  the thermal structure of sunspots, the convective nature of the solar supergranulation, latitudinal variation of the solar intensity, and temporal variation in solar magnetic structures on the smallest scales.

"Tropical clouds: A conundrum of the climate system"

Abstract:
Thunderstorm-clouds and mesoscale convective systems (MCS) in the tropics reach sizes of up to 2000 kilometers during the monsoon season in West Africa. Each cloud can produce within hours 1.5 times as much precipitation as Boulder receives during one year. Because these cloud systems reach altitudes up to 19 kilometers regular aircraft can not penetrate their upper glaciated parts and specialized high altitude research aircraft are required. These clouds are important for the climate system because they involve enormous amounts of energy, influence the radiative budget, are a central component of the hydrological cycle, and play a role for air chemistry. Largely because of the lack of in-situ measured data the tropical clouds constitute one of the biggest and at the same time one of the most unknown "screws" of the global climate system. For 11 years we have worked with the high altitude research aircraft M-55 "Geophysica" which is capable of reaching altitudes up to 21 km. As a former Russian espionage plane its conversion to a research aircraft constitutes a significant outcome of the "piece dividend".


In this seminar measurements pertaining to cloud and aerosol research are shown from the tropical campaigns in Brazil, Northern Australia, Burkina Faso (West Africa) and the Seychelles are presented. These are results of ultrafine particle measurements with the COndensation Particle measurement System (COPAS) and different cloud probes including relevant data from other in-situ instruments, and the data are put into the context of recent WB-57 measurements from Costa Rica as well as tropical ER-2 data back until 1996. The discussed measurements cover nucleation events in the tropical upper troposphere as well as background aerosol data from the Geophysica transfer flights to the various tropical locations. The vertical profiles measured over West-Africa significantly differ from all other tropical profiles probably due to the small albeit high reaching eruption from the Soufriere Hills volcano (Montserrat). Also in-situ data from cirrus clouds (obtained from concurrent optical particle counter and  cloud imaging probe measurements) over West African MCS systems and Cb overshoots in Australia are discussed as well as thin and subvisible cirrus cloud events.
Finally -because conducting such experiments in tropical locations and countries like Brazil, and Burkina Faso poses major challenges on a broad range of issues- a series of pictures and slides from the West African working environment will be shown at the end.

The PICARD Mission

Abstract:
PICARD mission is dedicated to the understanding of the solar activity origin and its consequences for the Earth's climate system. The measurements comprise the total and spectral solar irradiance, solar diameter, limb shape, solar asphericity, and helioseismic waves, which are key inputs for solar physics in particular for solar models, which role is the understanding of the physical processes taking place in the solar interior. To carry out this program, the PICARD team develops models of the solar convective zone, and of Earth's climate system especially tailored to allow for a variable solar spectral and total irradiance associated with dynamical coupling between troposphere and stratosphere.
The measurements will be carried out with two absolute radiometers, a bolometer, sunphotometers, and an imaging telescope. These instruments are built by IRMB (Belgium), LATMOS (France) and PMOD-WRC (Switzerland). They are placed onboard a microsatellite built by the French Space Agency CNES, with the launch foreseen for January 2009. The radiometers are similar to the ones on board SOHO. The imaging telescope contains an angular reference allowing a permanent control of the instrument geometric scale, which is referred to angular stars distances by rotating the spacecraft. Optical distortion and flatfield of the imaging telescope are regularly measured. The measurements carried out by the sunphotometers and the imaging telescope use the same wavelengths. Past and present solar diameter measurements on the ground reveal inconsistent variations with solar activity. To understand the role of the Earth's atmosphere, ground-based instruments will be also run during the mission allowing PICARD to extent its domain of interest to atmospheric physics by comparing ground and space diameters simultaneously measured as well as the atmospheric turbulence by a dedicated instrument. For extending the observations after the space mission, measurements from a stratospheric balloon will be initiated in September 2009.
The state of development of the mission will be presented as well as the PICARD mission center, which will process data to generate preliminary results for scientific analysis. PICARD and the NASA Solar Dynamics Observatory will be in space at the same period for complementary and simultaneous measurements, which will allow a strong synergy between the two missions. A key circumstance is the solar variability to be encountered during the mission. The launch as foreseen will allow to meet this requirement by providing measurements during the solar activity rising phase. The PICARD scientific team gathers scientist from France, Belgium, Switzerland, and US.

"Mass Spectroscopy of Planetary Objects"

Abstract:
All atmosphereless objects are exposed to the ambient meteoroid bombardment that erodes the surface and generates ejecta particles at a wide range of ejection speeds. Objects with radii bigger than 1000 km keep all particles with ejection speeds lower than ~1000 m/s. Therefore, such objects are enshrouded in clouds of dust particles that have been lifted by meteoroid impacts from the bodies' surfaces. These particles move on ballistic trajectories, most of which re-collide with their parent object. In-situ mass spectrometric analysis of these particles from an orbiting spacecraft provides spatially resolved mapping of the surface composition of the object. Particulates ejected from the surface of objects with a size above ~ 1500 km can be directly analyzed with an in-situ impact ionization mass spectrometer in orbit around the body (the method works at orbital speeds down to about 1 km/s). The composition of smaller objects (planetary satellites, asteroids, KBOs, and cometary nuclei) can be explored by fast fly-bys through their ejecta clouds. Even trace amounts of endogenic and exogenic minerals (e.g. salts), cyanogen, sulfur, and organic compounds which are embedded in ejected grains can be quantified with high accuracy. In some cases (e.g., on Europa), the achieved knowledge about surface-interior exchange processes may provide information about the internal composition of the satellite. This is also possible at moons that display active venting, e.g., Io, Enceladus.

The composition of the source moons of dusty rings is imprinted in the ring particles themselves. Likewise, the composition of asteroids, comets, and KBOs is conserved in particles of the zodiacal cloud and the Kuiper belt dust ring. Even the composition of our galactic neighborhood and nearby star forming regions can be probed by analyzing interstellar grains sweeping through the planetary system.

Special Date & Time:

Sept 25

4pm

Joint ATOC/LASP Seminar:

Remote Sensing of the Polar Middle Atmosphere

Abstract:
The middle is often a place to be avoided. As Margaret Thatcher once supposedly said, “Standing in the middle of the road is very dangerous; you get knocked down by the traffic from both sides.” But in the less politically charged atmosphere, the middle is re-emerging as a region of intense exploration because it is linked in still enigmatic ways to the lower layer where we live, and to the outer edge of space. To misquote Einstein, “In the middle....lies opportunity”. This talk will summarize some of the recent middle atmosphere research within ATOC and LASP. It will focus on three particular areas of investigation, including polar stratospheric ozone loss, mesospheric clouds, and the effects of energetic particle precipitation. Studies using measurements from different satellite instruments, including the Canadian Atmospheric Chemistry Experiment, the NOAA Solar Backscatter Ultraviolet instrument, and the NASA Limb Infrared Monitor of the Stratosphere, Aura Microwave Limb Sounder, Aeronomy of Ice in the Mesosphere, and various solar occultation instruments will be highlighted. In addition, simulations of relevant atmospheric processes using the NCAR Whole Atmosphere Community Climate Model will be described.

Seismic Discrimination of Thermal and Magnetic Anomalies in Sunspot
Umbrae

Abstract:
Efforts to model sunspots based on helioseismic signatures need to discriminate between the effects of (1) a strong magnetic field that introduces time-irreversible, vantage-dependent phase shifts, apparently connected to fast- and slow-mode coupling and wave absorption, and (2) a thermal anomaly that includes cool gas extending an indefinite depth beneath the photosphere. Simulations by Moradi et al of waves skipping across sunspots with photospheric magnetic fields of order 3 kG show travel times that respond strongly to the magnetic field and relatively weakly to the thermal anomaly by itself. We note that waves propagating vertically in a horizontally extended vertical magnetic field are relatively insensitive to the magnetic field and show that they are highly responsive to the attendant thermal anomaly. Travel-time measurements for waves with large skip distances into the centers of axially symmetric sunspots are therefore an important resource for discrimination of the thermal anomaly beneath sunspot umbrae from the magnetic anomaly. Sunspot simulations by Rempel, Schuessler, Cameron & Knoelker show thermal anomalies that are relatively superficial in acoustic terms, interacting strongly with acoustic waves in the upper 750~km beneath the quiet photosphere and insignificantly more than $\sim$4~Mm beneath the same. One-dimensional acoustic simulations applied to a thermal model representing these simulations show travel-time spectra somewhat larger than that prescribed by helioseismic signatures in small, nearly circular sunspots. However, Considerably reduced travel times for the model are substantially the result of a depth-dependent Wilson depression caused by the thermal deficit that is ~500-km at the photosphere. The travel-time reduction due to the Wilson depression generally outweighs the effect of a reduced sound speed in a cooled gas in slowing the upward propagation of the acoustic disturbance through the medium, reducing rather than increasing the travel times into the sunspot photosphere.

Water, Fire & Ice: In situ sampling of 'volcanic ashes' from Io and Enceladus

Abstract:
Compositional measurements carried out by Cassini's dust detector at Jupiter and Saturn are presented. Both planets are orbited by moons with active venting which expel particle streams into the system. These dust grains carry geochemical information of subsurface processes which are inaccessible by other means.

The largest volcanic eruptions on Io frequently inject particles, gas and plasma into the moons exosphere. From there the charged particles are subject to electromagnetic forces by which a certain fraction is dragged out of the Jovian system (the so called Jovian Stream Particles). The grains are surprisingly poor in sulphur components and predominantly consist of sodium chloride. The compositional analysis provides insight into condensation processes within the plumes of the large Pele-type volcanoes on Io.

At Saturn, the Cosmic Dust Analyser (CDA) has allowed the chemical characterisation of thousands of ice grains which have been expelled from Enceladus' cryo-volcanoes. In nearly all particles detected, sodium (Na) can be found in varying concentrations. Most spectra also show potassium (K) in lower abundance. In mass spectra that are particularly sodium rich, sodium salts (like NaCl and NaHCO3) are identified as Na bearing components. This is only plausible if the plume source is liquid water that is or has been in contact with the rocky material of Enceladus' core.

The abundance of minerals as well as the inferred basic pH of those grains exhibit a compelling similarity with the predicted composition of an Enceladus ocean. The Na-rich ice particles expelled through the plumes into the E ring are frozen droplets of a reservoir possibly still in contact with a large Ocean. The results provide many constraints for models of the plumes and their plumbing, including gas and grain production and their subsequent ejection. The analysis also allows refinement of models for a water-rock-interaction at the bottom of an Enceladian ocean.

"How Low is Low?  Latest News on this Current Solar Cycle Minimum"

Clouds in the summertime mesosphere: Recent findings from the AIM mission and outstanding questions

Abstract:
The NASA Aeronomy of Ice in the Mesosphere (AIM) satellite mission, now in its third year, is the first to have as its primary goal the study of Polar Mesospheric (Noctilucent) Clouds – how and why they vary in space and time. This talk will begin with some historical background, beginning with the earliest ground-based observations of noctilucent clouds in the late nineteenth century. As scientific knowledge and modern techniques have evolved over the past 125 years, these beautiful clouds are not yet understood in many details. I briefly discuss what we have learned, but devote some time to outstanding problems which have become “curioser and curiouser” over the years. These new questions have arisen now that we understand the basic nature of PMC (it is now certain they are composed of water ice). Despite the fact that remote sensing from space and lidar and radar technology, plus modeling advances, have revealed much new information on this enigmatic phenomenon, we still cannot answer basic questions such as: what has caused the clouds to change over the last three decades? Are the ice particles nucleated by debris from meteor ablation? Are they not only a sign but a consequence of anthropogenic alteration of our atmosphere? Is understanding the detailed microphysics of cloud formation important for understanding the role of these clouds as monitors of global change in the upper atmosphere? Possible solutions to some of these questions, and prospects for the future will be discussed.

The surface composition of Mercury: Recent results from MESSENGER reflectance spectroscopy measurements

Abstract:
More than 30 years ago NASA’s first mission to Mercury, Mariner 10, conducted three flybys of the planet.  Images were obtained of nearly half the surface, revealing features in close resemblance with those of the Moon.  The Mercury terrain was found to be characterized by heavily cratered regions with large areas of smooth plains, interpreted as possibly volcanic in origin.  While the two bodies appeared morphologically similar, the strong albedo dichotomy of the highlands and maria evident on the lunar nearside was found to be absent from Mercury.  Furthermore, ground-based observations of visible and near-infrared reflectance spectra from Mercury failed to unambiguously detect an absorption feature, located near 1 micron in wavelength, attributable to ferrous iron and found to be ubiquitous on the Moon.  The conclusion from this evidence was that the “iron planet” – a name due to its inferred large iron core – appeared to be virtually devoid of this element within the silicate materials of its crust.  The MESSENGER spacecraft, launched in August 2004, has made new measurements of Mercury and its environment during three gravity-assist flybys.  One of the seven instruments onboard the spacecraft, the Mercury Atmospheric and Surface Composition Spectrometer, was designed, built, and calibrated here at LASP.  MASCS measurement objectives include the acquisition of surface reflectance spectra and here we report an analysis of observations obtained during the first two flybys.  While the close similarity between Mercury and the Moon is apparent in this most recent data, subtle differences may yet reveal important clues to the surface composition of the innermost planet.  The ferrous-iron absorption feature continues to be absent in resolved spectra, but we conclude that iron may still be present in other mineral phases.

SEMINAR CANCELLED due to inclement weather
Solar EUV Irradiance Measurements: When Less Becomes More

Abstract:The output of the Sun at extreme ultraviolet wavelengths is a primary energy input to the upper atmospheres of the Earth and other planets. EUV photons ionize, dissociate, and heat the upper atmosphere. They create the ionosphere, heat the thermosphere, and initiate complex photochemistry. Because the solar EUV irradiance is highly variable at all timescales and wavelengths, so, too, is the upper atmosphere’s response to that variability. Human technological systems (such as satellite operations, telecommunications, and GPS navigation to name just a few) have become dependent on knowing the “space weather” of the upper atmosphere. In the not so distant past, uncertainties in the EUV irradiance have been as large as a factor of four at some wavelengths leading to large uncertainties in the state of the upper atmosphere. Carefully calibrated measurements on such missions as TIMED-SEE have answered many questions about the absolute value and the variability of the solar EUV. The EVE instrument on the soon-to-be launched SDO mission will provide the most comprehensive measurements of EUV irradiance in terms of accuracy, time cadence, and wavelength coverage and resolution. Because of insights gained from TIMED-SEE and expected with SDO-EVE, the future of EUV irradiance measurements is in significantly simpler monitoring instruments. In this talk I will discuss how less complex EUV measurements on the NOAA GOES-R series of weather satellites and the MAVEN mission can meet the future space weather needs at Earth and elsewhere in the solar system.

Modeling the Sun-Earth radiative connection

Abstract:
The current status and plans for our study of the coupling of the Sun and Earth atmospheres through the electromagnetic radiation will be discussed. It will be emphasized that the new findings point to the need of revising the calculations of the SSI variations effects on the Earth atmosphere, the hypothesis about Maunder minimum, and about stellar analogs.

This talk will loosely describe:

1. new findings regarding the structure of the solar atmospheric that affect the solar spectral irradiance at Earth (SSI);
2. new findings from observations of the solar spectral irradiance variations in various time-scales;
3. improvements in the capabilities for modeling and forecasting of the observed SSI variations;
4. context of the SSI variations and possible mechanisms by which the new observations can be explained;
5. ongoing efforts to understand the effects of SSI on the various layers of the Earth atmosphere.

Although this connection has been studied for a long time, only recent observations provide more realistic input than the largely hypothesized so far. Also, dramatic progress in our modeling ability puts us now in a much stronger position for finally determining this radiative connection and linking solar and Earth atmospheric physics in a meaningful way.

The Odin satellite - nine years of joint aeronomy and astronomy mission

The Swedish-led Odin satellite was launched in 2001 with a designed lifetime of two years. So far, Odin has provided nine years of scientific data to both atmospheric scientists and astronomers. This presentation describes Odin's concept of time-sharing between the two communities and reviews scientific highlights from both astronomy and the atmosphere.

Common ground for both missions is Odin's  microwave radiometer that detects a wealth of molecular species either by pointing into space or by limb-scanning the Earth's atmosphere. Water measurements have been a central focus for the astronomy mission, ranging from starburst galaxies and molecular clouds to Mars' atmosphere and the environment of comets. Odin's hunt for molecular oxygen has been another exciting part of the space mission. The aeronomy mission ranges from the tropopause to the lower thermosphere. It utilizes both the microwave instrument and an optical spectrograph. Results include new insights into the chemistry and dynamics of ozone depletion. In the mesosphere, water is again of major interest, both in the form of vapor and in the form of noctilucent clouds. This provides substantial overlap with the AIM mission at LASP.

Odin's aeronomers now continue their mission towards an entire solar cycle of atmospheric data, while the astronomers have moved on to microwave measurements with ESA's Herschel satellite.

Nov 13

(rescheduled)

Solar EUV Irradiance Measurements: When Less Becomes More

Abstract:The output of the Sun at extreme ultraviolet wavelengths is a primary energy input to the upper atmospheres of the Earth and other planets. EUV photons ionize, dissociate, and heat the upper atmosphere. They create the ionosphere, heat the thermosphere, and initiate complex photochemistry. Because the solar EUV irradiance is highly variable at all timescales and wavelengths, so, too, is the upper atmosphere’s response to that variability. Human technological systems (such as satellite operations, telecommunications, and GPS navigation to name just a few) have become dependent on knowing the “space weather” of the upper atmosphere. In the not so distant past, uncertainties in the EUV irradiance have been as large as a factor of four at some wavelengths leading to large uncertainties in the state of the upper atmosphere. Carefully calibrated measurements on such missions as TIMED-SEE have answered many questions about the absolute value and the variability of the solar EUV. The EVE instrument on the soon-to-be launched SDO mission will provide the most comprehensive measurements of EUV irradiance in terms of accuracy, time cadence, and wavelength coverage and resolution. Because of insights gained from TIMED-SEE and expected with SDO-EVE, the future of EUV irradiance measurements is in significantly simpler monitoring instruments. In this talk I will discuss how less complex EUV measurements on the NOAA GOES-R series of weather satellites and the MAVEN mission can meet the future space weather needs at Earth and elsewhere in the solar system.

Satellite and airborne remote sensing techniques are revolutionizing our understanding of the Greenland and Antarctic ice sheets, revealing changes that are in some cases much more dramatic than were ever expected. From collapsing ice shelves to accelerating outlet glaciers, to increasingly negative ice sheet mass balance, remote sensing capabilities are providing important insights into ice sheet behavior.

When coupled with in situ observations and robust process models, these large-scale four-dimensional observational capabilities are helping  us understand the nature of the changing ice cover, the processes that govern it, and what the implications for the future may be. In this talk I will examine the past, present, and future ontributions of remote-sensing observations to our understanding of the Earth's great ice sheets - one of the most rapidly changing components of the Earth system.