Staff Notes Daily Calendar Events

Thursday, June 20, 2013 - 3:00pm

In the context of atmospheric models, operational systems are those that dependably provide important, time-critical forecasts for use in decision-support systems.  They are characterized by the need for rapid data acquisition and model setup, reliable execution of the model, and post-processing activities that sometimes require delivery of model output timesteps as soon as they are completed.  In Alaska, reliable and timely weather forecasts are essential for a variety of commercial, recreational, and simple day-to-day living activities.  In addition to routine operational forecasting, Alaskans need to be prepared for surprise events.  Volcanic eruptions occur with some regularity in Alaska and Russia, affecting air transport and sometimes shutting down urban areas.  Uncontrolled wildfires in unpopulated regions are a fact of life, and Alaskans are sometimes subject to huge smoke emissions during the summer.   Additionally, Alaska is affected by non-predictable anthropogenic events such as toxic emissions and nuclear fallout.

 In addition to providing the tools for decision support, operational products from Alaska are also useful in a number of "downstream" research endeavors including road weather prediction systems, aviation icing products and greenhouse gas studies.  

 With a decade of experience in provision of operational products, often for large areas at high resolutions, we have gained a fair amount of experience and wisdom, and still have much to learn.  In this presentation we discuss some of the systems we have deployed, lessons learned, and the many exciting ambitions we have.

Presenter(s):
Don Morton
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022 - Large Auditorium

Posted by Scott Briggs (Email) at x1607
Lab/division hosting the event:
NCAR/UCAR Groups, Software Engineering Assembly
Thursday, June 20, 2013 - 3:30pm

Shuyi S. Chen
Professor of Meteorology and Physical Oceanography
Rosenstiel School of Marine and Atmospheric Science
University of Miami

The need for improving tropical cyclone (TC) intensity forecasts has been a driving force for much of the recent efforts in both TC research and operational community.  However, how to measure predictive skill for TC predictions is still an open question that causes confusion at times.  This study explores the predictability of TC intensity in numerical models.  A particular focus of this talk will be on how scale-dependent error growth leading to forecast uncertainty and limiting forecast skill.

Thursday, 20 June 2013, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Small Seminar Room 1001

Presenter(s):
Shuyi S. Chen
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1001

Posted by Michelle Menard (Email) at x8189
Lab/division hosting the event:
NCAR, NESL, MMM
Friday, June 21, 2013 - 12:00pm

How can observations be used to best evidence the influence on climate of human activities, among other forcings? Statistical methods of Detection and Attribution (D&A)were designed to answer this question. Conventional D&A methods are based on linear regression of spatial or temporal patterns extracted from one or several climate models ("optimal fingerprinting").

On the other hand, how can observations be used to best constrain a numerical model’s state variables and parameters? Methods of Data Assimilation (DA) meet this general purpose. Could D&A methods take advantage of recent progresses in DA? We argue that one may hope so. Indeed, under an inverse problem formulation of D&A, observations can be seen as a complex function of the forcings consisting of the full climate model itself. Under this perspective, D&A consists "merely" in reconstructing forcings from available observations by inverting the full climate model itself - a challenge for which recent DA-based parameter estimation schemes might be an answer.

We will discuss this general idea and illustrate it qualitatively by applying a simple data assimilation algorithm (AEKF) to a 1D radiative column model. The model simulates the vertical temperature structure of the atmosphere resulting from prescribed vertical profiles of key optical properties, as well as its dynamics when these optical properties are affected by changes in atmospheric constituents. In particular, it allows to represent the characteristic pattern of cooling of the stratosphere and warming of the troposphere under greenhouse gas forcing, which is a historical fingerprint used in D&A. We show that it is possible to reconstruct these forcings from the observation of the evolution of the vertical temperature profile based on data assimilation and thereby to evidence the influence of anthropogenic forcing on the evolution of climate.

Presenter(s):
Alexis Hannart
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Chapman Room

Posted by Carolyn Mueller (Email) at x2491
Lab/division hosting the event:
NCAR, CISL, IMAGe
Monday, June 24, 2013 - 2:30pm

Ian Grooms

Center for Atmosphere Ocean Science
Courant Institute of Mathematical Sciences, New York University

Efficient modeling of unresolved small-scale turbulence is of primary importance in simulations of large-scale geophysical fluid dynamics. In many geophysical and astrophysical settings the unresolved turbulence is not homogeneous/isotropic, being affected by rotation, stratification, moist processes, magnetism, etc., and the multiscale interactions with the resolved large scales are complex and consist of more than inertial-range energy transfer. Furthermore, small-scale feedback to the resolved scales is not completely determined by the resolved large scales. The random nature of the small scales requires stochastic models, which in turn can improve the robustness of ensemble-based prediction and state estimation algorithms.

Superparameterization is a multiscale framework that models unresolved scales by PDEs evolving on pseudo-physical domains embedded into the coarse grid of a general circulation model. Although the small-scale PDEs are deterministic, their chaotic/turbulent dynamics generate an effectively stochastic feedback to the large scales. Though successful in modeling tropical atmospheric moist convection, superparameterization remains computationally costly, and of limited generality.

We develop an improved framework for superparameterization that models the small-scale turbulent dynamics by stochastic, quasilinear PDEs rather than nonlinear, deterministic ones. This greatly improves the efficiency of the algorithm, and our mathematical framework for developing the large- and small-scale PDEs increases the generality of superparameterization. The resulting algorithm is developed and tested in two idealized turbulent models: the one-dimensional complex-scalar MMT equation, and two-layer quasigeostrophic turbulence. In both settings the algorithm achieves several orders of magnitude of reduction in computational cost compared to direct simulation of all scales, and produces qualitatively accurate results. This is particularly impressive in the quasigeostrophic tests where the algorithm successfully parameterizes the inverse cascade of kinetic energy from unresolved to resolved scales. Future directions include more realistic applications, and optimization of the numerical algorithm.

Presenter(s):
Ian Grooms
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Main Seminar Room

Posted by s gentile (Email) at x2480
Lab/division hosting the event:
NCAR/UCAR Groups, GTP
Monday, June 24, 2013 - 3:30pm

The zonal mean mass circulation of the stratosphere (i.e. the Brewer-Dobson circulation) is characterized by upwelling in the tropics and downwelling at high latitudes. The ascent near the tropical tropopause largely controls the composition of air entering the stratosphere. Despite its relevance, tropical upwelling is poorly constrained by observations and its magnitude, variability and specific forcings are currently uncertain.

The variability of upwelling is especially evident on tracers with steep vertical gradients across the tropical tropause, such as ozone and carbon monoxide. We use satellite observations of these tracers to investigate the circulation near and above the tropical tropopause, and compare different indirect estimates of upwelling. The observations are complemented by parallel analyses using WACCM, and we quantify the influence of tropical upwelling and eddy transport on tracer variability spanning daily to seasonal timescales.

Finally, we identify the dynamical forcings leading to the observed sub-seasonal fluctuations in upwelling (linked to variability in the tracers). The Brewer-Dobson circulation is dynamically driven, and our results demonstrate the importance of extratropical synoptic-scale and planetary waves in forcing upwelling across the tropical tropopause.

Presenter(s):
Marta Abalos
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022

Posted by Trinh Guenther (Email) at x1401
Lab/division hosting the event:
NCAR, NESL, ACD
Thursday, June 27, 2013 - 12:00pm

Part I: Functional and Surface Boxplots for Visualization of
Complex Curve/Image Data:  An Application to Precipitation
and Climate Model Output

In many statistical experiments, the observations are functions by nature, such as temporal curves or spatial surfaces/images, where the basic unit of information is the entire observed function rather than a string of numbers.  For example the temporal evolution of several cells, the intensity of medical images of the brain from MRI, the spatio-temporal records of precipitation in the U.S., or the output from climate models, are such complex data structures.  Our interest lies in the visualization of such data and the detection of outliers.  With this goal in mind, we have defined functional boxplots and surface boxplots based on the center outwards ordering induced by band depth for functional data or surface data.  We illustrate the construction of a functional boxplot on a series of sea surface temperatures related to the El Nino phenomenon and its outlier detection performance is explored by simulations.  As applications, the functional boxplot is demonstrated on spatio-temporal U.S. precipitation data for nine climatic regions and on climate general circulation model (GCM) output.  Further adjustments of the functional boxplot for outlier detection in spatio-temporal data, fast ranking of curves and images, and extensions to surface boxplots are discussed as well.  The talk is based on joint work with Ying Sun.

 Part II: Paradigms for a 21st Century University

KAUST is a graduate research institution, founded in 2009 by King Abdullah of Saudi Arabia, with research thrusts in energy, environment, food, and water for a sustainable planet, and supporting thrusts in core capabilities (modeling, simulation, analytics, software, and hardware).  As a 45-sq km international academic village on the shores of the Red Sea, created to be a 21st century "House of Wisdom" in the tradition of the ninth century Bayt al Hikmah that gave the world some of its modern mathematics, physics, chemistry, and medicine, KAUST has been endowed with world-class facilities and has recruited a world-competitive research faculty. KAUST awards degrees in Applied Mathematics and Computational Science, Bioscience, Chemical Science, Chemical and Biological Engineering, Computer Science, Earth Science and Engineering, Electrical Engineering, Environmental Science and Engineering, Marine Science, Materials Science and Engineering, and Mechanical Engineering. Currently, KAUST enrolls about 800 students from about 60 different countries.  The language of instruction is English. KAUST is co-educational and is established upon principles of intellectual freedom, non-discrimination, and merit-based promotion. For Fall 2013, KAUST seeks ambitious, academically talented, and highly motivated doctoral and master's candidates in sustainable technologies and the enabling sciences from the worlds leading institutions to participate in discovery and translation into start-up enterprises. The speaker will present KAUST¹s programs and take questions about life in today's Middle East and about starting a university from scratch

Presenter(s):
MARC G. GENTON
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Penthouse Conference Room

Posted by Carolyn Mueller (Email) at x2491
Lab/division hosting the event:
NCAR, CISL, IMAGe
Tuesday, July 9, 2013 - 8:00am, Wednesday, July 10, 2013 - 8:00am, Thursday, July 11, 2013 - 8:00am, Friday, July 12, 2013 - 8:00am

The 2013 NCAR Workshop on Climate and Health will focus on two related atmospheric hazards, the individual and combined effects of extreme heat and air pollution on human health. The purpose of the workshop is to train researchers (graduate students, post-docs and early career scientists and faculty) on how to develop robust interdisciplinary research projects in the complex area of climate and health. The four-day workshop will take place from 9-12 July 2013 and will include lectures on relevant topics in climate and climate change and in public health and human health, vulnerability studies, urban studies, statistics, and special tools for analysis (e.g., GIS or NCAR model output datasets). In addition, a few successful research projects will be highlighted, providing detailed analyses of the methods and components of the projects that led to their success. There also will be multiple opportunities to engage public health practitioners and climate scientists to discuss the integration of epidemiology, ecology, behavioral science, modeling and atmospheric science.

Presenter(s):
NCAR and CDC
Type of event:
Seminar/Symposium
Building:
FL1
Room:
EOL Atrium

Posted by Mary Hayden (Email) at x8116
Lab/division hosting the event:
NCAR, RAL, CSAP
Tuesday, July 9, 2013 - 8:00am, Wednesday, July 10, 2013 - 8:00am, Thursday, July 11, 2013 - 8:00am, Friday, July 12, 2013 - 8:00am

The 2013 NCAR Workshop on Climate and Health will focus on two related atmospheric hazards, the individual and combined effects of extreme heat and air pollution on human health. The purpose of the workshop is to train researchers (graduate students, post-docs and early career scientists and faculty) on how to develop robust interdisciplinary research projects in the complex area of climate and health. The four-day workshop will take place from 9-12 July 2013 and will include lectures on relevant topics in climate and climate change and in public health and human health, vulnerability studies, urban studies, statistics, and special tools for analysis (e.g., GIS or NCAR model output datasets). In addition, a few successful research projects will be highlighted, providing detailed analyses of the methods and components of the projects that led to their success. There also will be multiple opportunities to engage public health practitioners and climate scientists to discuss the integration of epidemiology, ecology, behavioral science, modeling and atmospheric science.

Presenter(s):
NCAR and CDC
Type of event:
Seminar/Symposium
Building:
FL1
Room:
EOL Atrium

Posted by Mary Hayden (Email) at x8116
Lab/division hosting the event:
NCAR, RAL, CSAP
Tuesday, July 9, 2013 - 8:00am, Wednesday, July 10, 2013 - 8:00am, Thursday, July 11, 2013 - 8:00am, Friday, July 12, 2013 - 8:00am

The 2013 NCAR Workshop on Climate and Health will focus on two related atmospheric hazards, the individual and combined effects of extreme heat and air pollution on human health. The purpose of the workshop is to train researchers (graduate students, post-docs and early career scientists and faculty) on how to develop robust interdisciplinary research projects in the complex area of climate and health. The four-day workshop will take place from 9-12 July 2013 and will include lectures on relevant topics in climate and climate change and in public health and human health, vulnerability studies, urban studies, statistics, and special tools for analysis (e.g., GIS or NCAR model output datasets). In addition, a few successful research projects will be highlighted, providing detailed analyses of the methods and components of the projects that led to their success. There also will be multiple opportunities to engage public health practitioners and climate scientists to discuss the integration of epidemiology, ecology, behavioral science, modeling and atmospheric science.

Presenter(s):
NCAR and CDC
Type of event:
Seminar/Symposium
Building:
FL1
Room:
EOL Atrium

Posted by Mary Hayden (Email) at x8116
Lab/division hosting the event:
NCAR, RAL, CSAP
Tuesday, July 9, 2013 - 8:00am, Wednesday, July 10, 2013 - 8:00am, Thursday, July 11, 2013 - 8:00am, Friday, July 12, 2013 - 8:00am

The 2013 NCAR Workshop on Climate and Health will focus on two related atmospheric hazards, the individual and combined effects of extreme heat and air pollution on human health. The purpose of the workshop is to train researchers (graduate students, post-docs and early career scientists and faculty) on how to develop robust interdisciplinary research projects in the complex area of climate and health. The four-day workshop will take place from 9-12 July 2013 and will include lectures on relevant topics in climate and climate change and in public health and human health, vulnerability studies, urban studies, statistics, and special tools for analysis (e.g., GIS or NCAR model output datasets). In addition, a few successful research projects will be highlighted, providing detailed analyses of the methods and components of the projects that led to their success. There also will be multiple opportunities to engage public health practitioners and climate scientists to discuss the integration of epidemiology, ecology, behavioral science, modeling and atmospheric science.

Presenter(s):
NCAR and CDC
Type of event:
Seminar/Symposium
Building:
FL1
Room:
EOL Atrium

Posted by Mary Hayden (Email) at x8116
Lab/division hosting the event:
NCAR, RAL, CSAP
Wednesday, July 17, 2013 - 3:00pm
The hydromagnetic nature of the Sun’s magnetids The phenomenon of the Sun reversing its global magnetic polarity with a periodicity of approximately eleven years is briefly reviewed to comment on the current hydromagnetic understanding of the dynamo in the solar interior and the transport of the generated magnetic flux for mixing into the electrically highly-conducting solar atmosphere. Space and ground-based observations today describe the solar atmosphere with truly amazing ranges of photon/particle energies and unprecedented resolutions in space and time. The review will concentrate on the million-degree hot, tenuous corona, the outer atmosphere that expands into the solar wind flowing supersonically past the Earth to beyond Pluto. The approximate conservation of magnetic helicity and a natural tendency to form thin current sheets are basic to the magnetic heating of the corona and its long-lived magnetic structures that intermittently flare and blow off as CMEs. This view of how the global magnetic field takes its own time to reverse polarity in the voluminous corona is interesting physics, with the intriguing implication that organized magnetic systems do make tortuous ways from the solar interior into the solar wind.
Presenter(s):
Boon Chye Low
Type of event:
Seminar/Symposium
Building:
CG1
Room:
2126

Posted by Wendy Hawkins (Email) at x1552
Lab/division hosting the event:
NCAR, HAO