- Atmospheric and oceanic systems are characterized by multi-temporal and spatial scales, which are not directly and explicitly addressed in major data assimilation algorithms. These major data assimilation algorithms are derived from the maximum likelihood or minimum variance estimate, including three- and four- dimensional variational (3/4DVAR) methods and the Kalman filter and smoother methods. In these methods, the background error covariance plays a central role. However, a difficulty arises when the error covariance is constructed for a high-resolution model, which involves multi-scale systems by nature. The error covariance is usually dominated by large scale components, since meso- and small scale components account only for a relatively small part of variances in both ocean and atmosphere. As a consequence, high-resolution measurements are difficult to be effectively assimilated and the impact of high-resolution measurements is often diminished. A modified 3DVAR method for multi-scale systems will be presented. In addition, some issues related to adjoint sensitivity analysis will be discussed.

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- Granada, a city in the southeast of Spain, has peculiar geographic conditions that, along with its proximity to Africa and the Saharan desert, make it an excellent spot for aerosol research. Alberto will present an overview of the research and the different projects under way in the Atmospheric Physics Group at University of Granada with a special emphasis on a new technique for aerosol characterization with a sky imager that is regularly used for cloud cover characterization.

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- Aerosol indirect effects (aerosol’s effects on climate through modifying cloud properties) have been one of the largest uncertainties in projecting future climate change. Difficulties in studying aerosol indirect effects arise from complicated processes involved in both aerosol and cloud physics. In order to better understand aerosol indirect effects, we coupled a global aerosol model (LLNL/IMPACT) with an atmospheric circulation model (NCAR CAM3), and improved both aerosol and cloud representations in the coupled model. In this talk, we will explore how these improvements in aerosol and cloud representation advance our understanding of aerosol indirect effects. We will first examine how aerosol nucleation mechanisms and primary sulfate particles affect the concentration of cloud condensation nuclei (CCN) and further affect the aerosol first indirect effect. Our results showed that the forcing from various treatments of aerosol nucleation ranges from -1.22 to -2.03 w/m². This large variation shows the importance of better quantifying aerosol nucleation mechanisms for the prediction of CCN concentrations and aerosol indirect effects. We will then examine how homogeneous and heterogeneous ice nucleation mechanisms affect ice supersaturation regions and cloud occurrence frequency in the upper troposphere. Our results showed that potential change in ice nucleation mechanisms that might come from anthropogenic aerosols can alter ice supersaturaiton regions and cirrus cloud occurrence frequency significantly.

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- The method of moments (MOM) offers a statistically based alternative to aerosol simulation that is more efficient than sectional methods and more accurate than modal methods. Closure of the moment evolution equations and estimating aerosol physical and optical properties directly from the moments are the two major limitations of the MOM that have been overcome using quadrature (Q) methods developed at BNL during the past decade. Key moments of the aerosol population, including number, mass, and mixed moments, e.g. the variances and co-variances entering the covariance matrix of a principal components analysis (PCA), are tracked in place of the distribution itself. The resulting QMOM is highly efficient, yet provides the comprehensive representation of natural and anthropogenic aerosols, and of their mixing states and direct and indirect effects, that the Community Climate Science Model (CCSM) will require. This talk will review the QMOM and describe our recent progress on developing the fundamental statistical foundation of the method, on the representation of aerosol mixing state and particle size/shape/composition distributions using PCA, and on aerosol module development - recently completed for the NASA GISS model and now under development for the NCAR Community Atmospheric Model (CAM).


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- Methane hydrates are inclusion compounds in which water molecules form a well-defined cage to encapsulate a methane molecule. The methane concentration of 14 mol% in methane hydrates is high enough to sustain a controlled flame that appears as “Burning Ice”. The seismic data and recovery of hydrate cores from several worldwide locations show that gas hydrates are a common occurrence, both in permafrost and marine settings where high-pressure and low-temperature conditions coexist. There is growing concern of kinetic instability of methane hydrate with respect to slight temperature changes that could impact seafloor stability and methane gas arising from massive hydrate dissociation in the ocean may contribute to global warming. In sediment-hosted methane hydrates, the sediment-hydrate interaction governs the mechanical strength as well as other geophysical properties of formations or well bores in the event of a rapid release of methane. For the work sponsored by the Office of Fossil Energy, U.S. DOE, we are investigating the laboratory-scale hydrate growth and decomposition habits of hydrates formed in natural depleted sediments, recovered from Blake Ridge and the Gulf of Mexico. The hydrate formation/dissociation kinetic data collection is being carried out in the BNL Flexible Integrated Study of Hydrates (BNL-FISH) unit fitted with two customized high-pressure cells, in which methane input/output is precisely measured. The hydrate growth behavior is studied by Computed Microtomography (CMT) at the Beamline X-2B, NSLS. Taken together, these data will aid in understanding both the micro as well as macro behaviors of methane hydrates. The ultimate goal is develop correlation with well log data and consider the relationship of methane hydrate occurrences to the Climate Change models.

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- There is a vigorous debate now about whether our oil, natural gas, and coal resources will be sufficient in the future. At the same time, there is an intense effort to predict the changes in climate that will result from consuming these fossil fuels. There has been surprisingly little effort to connect these two. Do we have a fossil-fuel supply problem? Do we have a climate-change problem? Do we have both? Which comes first? We will see that the trend for future fossil-fuel production is less than what is assumed in the United Nations climate-change assessments. The implication is that an understanding of producer limitations could help us do a better job of predicting climate change. We will also see that the time scale for exhausting fossil fuels is much smaller than that for global temperature change. This means that to reduce the future temperature rise, it is critical to reduce the total fossil-fuel production, not just slow it down. One possible approach for reducing total production would be to establish fossil-fuel preserves on federal lands that would be off limits for new leases for drilling and mining.


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- I will describe progress in two emerging techniques for cloud property remote sensing using very different instrumentation, but very similar phenomenology. Ground-, aircraft- or space-based multiple scattering lidar is an active approach, currently effective only at night, that uses relatively standard lidar technology. Differential absorption spectroscopy in the oxygen A-band is a passive approach available during daytime that, interestingly, delivers different amounts of cloud information depending on whether transmitted or reflected sunlight is analyzed. However, both modalities are predicated on the same time-dependent 3D radiative transfer captured by Green function theory. Fortunately, this theory is analytically tractable in the case of optically thick clouds thanks to Eddington's diffusion approximation, akin to the two-stream model of GCM fame. In both cases, a plane-parallel, but not necessarily internally uniform, slab is the preferred cloud geometry.

However, when cloud structure deviates strongly from the case of an unbroken single stratus layer, O₂ A-band spectroscopy morphs from a cloud remote sensing technique into a powerful diagnostic of cloud-radiation interaction from the standpoint of gaseous absorption, a key process shaping the solar radiation budget at GCM grid scales. Accordingly, the underlying transport theory evolves from standard diffusion to an ``anomalous'' version. I will frame this evolution in modeling as a unique opportunity for assessing the performance of GCM shortwave parameterization schemes for cloud representation (overlap probability, unresolved variability, spatial correlations, and so on). For related reasons, A-band spectroscopy also promises to become an important link in the chain between ARM's futuristic 3D cloud tomography products under development at BNL and the Holy Grail of accurate 3D radiation bugdet prediction for given clouds.

In short, we have a story about very promising instrument/diagnostic developments that were seeded by cutting-edge radiation transport theory.


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- In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique.

Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model.

In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the interactions between clouds, precipitation, and aerosols will be presented. Also how to use of the multi-satellite simulator to improve precipitation processes will be discussed.



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- “Elemental Carbon” is a proxy for soot, which is a very harmful aerosol-compound. Soot absorbs solar radiation, thereby acting as a greenhouse component. Black Carbon is the measure for this aspect of soot. It is an ill-defined quantity: its amount is that of EC in reference samples with the same blackness.

Black Smoke is an old aerosol-parameter that is based on the darkness of filter samples. After a long period of data-mining I recently found that Black Smoke and Black Carbon are highly correlated. It could also be concluded that Black Smoke is a robust measure for aerosol-absorptivity. It is hence a good proxy for soot, certainly in the following relative sense. There are drastic changes over time in the levels of Black Smoke. This is evidence of drastic changes in the levels of soot and its environmental impact; issues that will be investigated next.



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- Hydrological and energy cycle of atmosphere involves a wide range of cloud scales, from shallow cumulus clouds to superclusters and MJO. The mesoscale organization of convection has been successfully studied by cloud resolving models (CRMs); however, because of high computational expense, the small-scale clouds have not been generally resolved by CRMs and their effect on deep convection has been usually treated as sub-grid scale process. The small-scale turbulence and shallow clouds have generally been a domain of large-eddy simulation (LES) models. Recently, the progress in supercomputers have allowed to apply LES-type grid resolution to modeling deep clouds and mesoscale organization of convection. The results of one of such LES simulations performed on NY Blue supercomputer using the System for Atmospheric Modeling (SAM) will be presented. Challenges associated with the so-called 'data tsunami' of large-scale computing will be discussed.


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- Worldwide, airports are growing and emissions associated with aircraft activity are increasing. Domestically, National Air Quality Standards are being tightened. A major part of airport expansion projects involves environmental review. The traditional method of estimating aviation emissions established in the 1970s needs to be updated.

  This talk describes the results from several measurement programs using a mobile laboratory to characterize aircraft emissions. A novel approach, using wind-advected plumes will be described. The gas and particulate results from staged and in-use measurement of high bypass ratio turbofan engines (jet engines) will be presented. The implications for dispersion model development, inventory improvement, the impact on local air quality and future measurement projects will be discussed.



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- Atmospheric modeling, one of the first high performance computing (HPC) applications, remains a cycle-hungry domain today as we move to petascale computing. Designed from the outset for HPC, the Weather Research and Forecast (WRF) - widely used for operational weather forecasting, hurricane prediction, regional climate simulation, atmospheric chemistry, and basic atmospheric research -- is now exploiting systems comprising tens of thousands of cores as well as non-traditional architectures such as Graphics Processing Units. This talk presents a look forward at HPC and numerical weather prediction as a scientific computing challenge.



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- Atmospheric aerosol particles host a very complex mixture of organic and inorganic components. A significant fraction of organics present in aerosol particles are surface active, such as linear alkanoic and alkenoic acids or aromatics with hydrophilic substituents. Using reasonably well defined proxy systems, we have started to look at three different aspects of organic coatings: first, they may establish a barrier towards the transfer of trace gases from the gas phase into the aerosol phase. We have used the fast uptake of nitric acid to deliquesced NaCl particles to probe the effect of long chain C9 to C18 saturated and unsaturated fatty acids, indicating that the monolayer forming properties of these fatty acids determines the degree of reduction of phase transfer of nitric acid to the aqueous particles. Second, the chemical environment in a coating is substantially different from that in either the pure organic or the aqueous bulk phases. This is demonstrated with ozonolysis studies of oleic acid monolayers on deliquesced NaCl particles, which shows substantial formation of H2O2, exceeding that from bulk oleic acid ozonolysis or that known from alkene oxidation in the gas phase. Third, a number of species in organic coatings are absorbing light in the visible and UVA wavelength range. We have specifically investigated photosensitized redox processes that lead, among other things, to light induced reaction of organics with nitrogen dioxide and ozone, the former becoming a substantial source of nitrous acid in the lowermost troposphere.



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- Estimates of how humans are affecting the energy balance of the planet are uncertain largely due to complicated interactions between aerosols and clouds. A major factor in this uncertainty is the how humans have changed the number of particles in the atmosphere that may act as cloud condensation nuclei (CCN). Ultrafine particles (particles with diameters smaller than 100 nm), are often too small to act as CCN; however, a large fraction of particles in the atmosphere begin as ultrafine particles and must grow to CCN sizes. In this talk we will explore how uncertainties in ultrafine aerosol sources, such as nucleation and emissions from primary sources, lead to uncertainties in predictions of CCN concentrations. The impact of these ultrafine particles on CCN will be explored using both a simple model of aerosol timescales as well as a detailed 3-D general circulation model with aerosol microphysics. Finally, we will investigate the relative contribution of primary aerosol emissions and aerosol nucleation to CCN globally.



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- Atmospheric aerosols play a fundamental role in Earth’s atmospheric chemistry and climate. Soot is an absorbing aerosol, though the magnitude of that absorption has largely been determined by measuring the optical properties of uncoated soot. It has been proposed that coated soot might absorb radiation more efficiently than uncoated soot, thus warming the climate more than previously suspected. For this study, soot is generated in a well-controlled Santoro-Style diffusion flame burner with ethylene as the fuel, and has been successfully coated with dibutyl phthalate (DBP), a non-absorbing material. DBP has a refractive index of 1.490 (real part), which is similar to the refractive index of sulfuric acid (n=1.426) at 589 nm. DBP is substituted for the commonly found sulfate coated particles for several reasons including safety and instrument integrity. By changing the temperature of the DBP, the vapor pressure of the DBP is changed and consequently, the coating thickness can be changed. Extensive work has taken place in controlling the coating process as well as in the generation and delivery of the aerosols for analysis. The aerosols are classified with a differential mobility analyzer (DMA). From the DMA the aerosols are sent to a condensation particle counter (CPC) for size distributions or are analyzed. This talk will discuss some of the background work involved in this study as well as some of the techniques used in this experiment. 



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- Doppler cloud radar spectra provide a measure of the reflectivity- weighted velocity distributions of scatterers within a sampling volume, and as such, are snapshots of the interplay between atmospheric dynamics and hydrometeor microphysics. Distortions in spectrum morphologies from a commonly assumed gaussian distribution contain valuable information about atmospheric state that is not captured by the traditional three- moment spectrum model comprised of reflectivity, spectral width, and mean Doppler velocity. This talk will discuss three applications that analyze Doppler radar spectra in greater detail to extract useful information: classification of hydrometeor phase (ice, liquid, mixed), prediction of high spectral resolution lidar measurements, and the detection of insect-generated clutter. Potential future directions of this generalizable methodology will also be discussed.



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- The interaction of turbulence and aerosol particles in and surrounding clouds is important in understanding the microphysical properties of clouds. The seminar will detail the measurement of atmospheric turbulence with the gustprobe on the DOE G-1 Research Aircraft. This includes the techniques and associated difficulties of calculating atmospheric turbulent energy dissipation rates, updraft/downdraft velocities, and turbulent microphysical Reynolds numbers from the gustprobe data. Examples will be shown from the MASE 2005 study over the Pacific and the CHAPS 2007 study in Oklahoma. The MASE example will include the ubiquitous aerosol layer which is observed directly above marine stratus clouds. This 25 meter thick layer will be shown to be turbulently coupled to the marine stratus cloudtop, with turbulent exchange of aerosol particles between the layer and the cloudtop. Microphysical and chemical data will be shown which indicates that this layer is a region of aerosol production, as evidenced by enhanced aerosol particle, ozone and sulfur dioxide concentrations.



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