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ASP Seminar Series

The NCAR/ASP seminar series features monthly talks given by invited speakers from NCAR and other research institutions from the Boulder area. These talks primarily address an audience of graduate students, postdocs and young scientists from various fields related to atmospheric, oceanic, or solar sciences. Advanced researchers also enjoy the talks. The aim of the seminar series is to engage scientific interest amongst students, postdocs and scientists in a variety of atmospheric science issues. The invited speakers are asked to give an overview of their research areas, including new or controversial ideas in the field, and highlight results from their work. The talks have a strong educational component that is enjoyed by both experts and non-experts in the field. The selected topics reflect the broad interests of the atmospheric, oceanic, or solar science communities.

For recorded seminars, the webcast URLs are as follows.
Foothills Lab: http://www.fin.ucar.edu/it/mms/fl-live.htm
Mesa Lab: http://www.fin.ucar.edu/it/mms/ml-live.htm

2012 - 2013

Unless otherwise noted, all seminars will start at 11:00 AM, and lunch with the speaker will begin immediately following the seminar.

2012

Date

Speaker

Affiliation

Location

Lunch

Title

Chair

Abstract

Oct. 3

Guy Brasseur

NCAR Distinguished Scholar

TBD FL or ML

TBD

From Climate Science to Planetary Stewardship: Challenges for the Scientific Community

TBD


Dec. 12

Brian O'Neill

NCAR CGD and ISP

ML

TBD

Topic: HDI, Emissions, and Vulnerability in integrated assessment models

Sara


















2013

Date    

Speaker        

Affiliation                        

Location      

Lunch

Title                                                                                                                        

Chair

Abstract

Jan. 24

Dave Gochis

NCAR RAL

FL2-1022

FL2-1002

WRF-Hydro: A hydrological modeling extension package
for the Weather Research and Forecasting System

Andy

Improvement of predictions of water cycle processes such as precipitation, runoff, evapotranspiration and terrestrial storages remain as a grand challenge in Earth System science. For a long-time such predictions were handled in a two-step manner where predictions of precipitation were fed into an offline or ‘uncoupled’ hydrological model which would produce
predictions of streamflow, aquifer recharge or inundated areas. While appropriate for many applications, recent research has suggested that important feedbacks between the land-atmosphere system can be neglected using such approaches. Also, use of uncoupled approaches do not guarantee that certain key processes that are shared between atmospheric and hydrological models, such as evapotranspiration are treated equally which can lead to inconsistencies in model predictions. Hence there is increasing demand for more complete and unified prediction systems which
explicitly couple terrestrial hydrological processes with atmospheric processes. Similarly there is also a need to represent surface processes at increasingly fine scales which explicitly resolve key forcing mechanisms on the landscape. These needs have driven the development of a coupling architecture within the Weather Research and Forecasting (WRF) model which can accommodate some of the unique characteristics of hydrological models. This new architecture called WRF-Hydro aims to improve the study and prediction of coupled hydrometeorological processes
by providing an environment for developing, coupling and testing new hydrological model components within the WRF model. This seminar will provide a thorough description of the WRF-Hydro system and its evolution as it is preparing for initial release in the spring of 2013. We will also provide some example applications of the WRF-Hydro system for several different prediction problems the model has been applied to around the world.

Feb. 13

Sue Ellen Haupt

NCAR RAL

FL2-1022

FL2-1002

Predicting Atmospheric Realizations:
Dealing with Uncertainty in Applied Meteorology

Lili

Although atmospheric models provide a best estimate of the future state of the atmosphere, due to sensitivity to initial conditions, it is intractable to predict the precise future state.  For applied problems, however, users often expect just that – predicting a specific realization of atmospheric flow. How can meteorologists make useful predictions in the face of such uncertainty?  By applying state-of-the-science modeling, assimilating observations, and applying appropriate post-processing techniques, we can approach predicting realizations of atmospheric flow and quantifying their uncertainty. Predicting a particular realization of an evolving flow field requires knowledge of the current state of that field and assimilation of observations into the model.  A first example is modeling atmospheric transport and dispersion of a contaminant when the observation is of the transported contaminant, a problem that exemplifies the issue of uncertain turbulent flow.  We will discuss the inner vs. the outer variability and how both can be recovered with judicious use of the observations. In this case, the problem is compounded by the fact that the field observed is a tracer that is advected and mixed by the flow field, but does not directly alter the flow field.  This one-way coupled system presents a challenge: one must first infer the changes in the flow field from observations of the contaminant, then assimilate that data to recover both the advecting flow and information on the subgrid processes that provide the mixing. To accomplish such assimilation requires a robust method to match the observed contaminant field to that modeled.  Here we use a genetic-algorithm variational approach to dynamically assimilate the concentration and use that to infer both the resolved and unresolved variables. 
Next we will show how assimilation can help bridge the gap between modeling flows at the mesoscale and flows at the fine scale that is often important for resolving flow around local features.  By assimilating mesoscale model data into a computational fluid dynamics model, we can force the fine scale model to with the features at the mesoscale, providing a coupling mechanism.  Additionally, we look at ensemble mesoscale prediction in terms of predicting realizations and quantifying their uncertainty. Computational intelligence techniques can be used to identify regimes, which allows closer prediction of a realization.  Postprocessing allows better quantification of uncertainty.Finally, we will look at the value of assimilation and ensemble prediction for the renewable energy industry.  If the industry decision makers have confidence in the wind and solar power forecasts, they can build their power allocations around the expected renewable resource, saving money for the ratepayers as well as reducing emissions.

Feb. 27

Matt Newman

ESRL/PSD, NOAA

ML Main Seminar Room

ML Cafeteria

Empirical models of intraseasonal to decadal variability and predictability

Toby

Climate variability is often characterized by a notable separation between the dominant time scales of interacting processes. For example, rapid weather forcing of the slow ocean can be approximated as white noise forcing of a damped integrator, or univariate red noise. A similar approximation can be applied to the more general case of anomalies representing many evolving regional patterns of climate variables, yielding multivariate red noise. The empirical technique determining multivariate red noise from observations is called linear inverse modeling (LIM). In this talk it is shown that LIMs make forecasts whose skill is competitive with current global forecast coupled GCMs. At all forecast time scales, for some seasons and regions LIM skill is actually higher on average than the CGCM. LIM can thus serve as a key forecast benchmark, and in particular can help to focus on where CGCM improvements should be targeted to yield the most significant forecast gains. The geographical and temporal variations of forecast skill are also generally similar between the LIM and CGCMs. This makes the much simpler LIM an attractive tool for assessing and diagnosing overall climate predictability as well as the predictability of climate modes such as the MJO, ENSO, PDO, and AMO.

March 26

Judith Perlwitz

NOAA

ML Main Seminar Room 3:30 PM

Southern Sun

 

Toby

 

Apr. 17

Scott Ellis

 

FL2-1022

 

 

 

 

May 23

Ryan Torn

University at Albany

FL

 

 

Lili

 

2012-2013 room reservations spreadsheet

----2011 - 2012

Unless otherwise noted, all seminars will start at 11:00 AM, and lunch with the speaker will begin immediately following the seminar.

2012

Date

Speaker

Affiliation

Location

Lunch

Title

Chair

Abstract

Apr. 18

Roy Rasmussen

NCAR/RAL

FL2-1022

FL2-1003

TBA

Andy Newman

 

Apr. 6

Greg Holland

NCAR/NESL/MMM

FL2-1022

FL2-1002

Climate Impacts on Weather Extremes:
Variability and Change; Hurricanes to Droughts

Brian Tang

Societal vulnerability to weather arises largely from relatively rare events at the extremes of the spectrum. Such high-impact weather includes: extended droughts, heat waves, major hurricanes, extreme local rainfall and snowfall, ice storms, European wind storms, and severe local storms and tornadoes. Perhaps somewhat paradoxically, our vulnerability to property loss and societal disruption is increasing as society becomes more complex and interconnected, and as private, industrial and commercial development expands in high-risk areas. Understanding and predicting variations and changes in weather extremes is thus a major societal issue, encompassing urban commercial and industrial planning, watershed maintenance and design, insurance types and premiums, and government policy.

In this presentation I examine the difficulties of differentiating climate change from variability and the question of when observable human-induced climate change commenced, together with the use of extreme value theory to objectively assess the intensity and frequency of extreme events. These two themes lead to the suggestion that weather extremes respond strongly to climate variability and change and, somewhat non-intuitively, that such variability and change is best interpreted through weather extremes. Finally the potential of climate change contributions to current high-impact weather events will be assessed.

Mar. 21

Jim White

CU

ML Main Seminar Room

TBA

TBA

Will Wieder

 

Feb. 15

Jim Brasseur

Penn State

FL2-1022

FL2 1002

"Accuracy in LES Prediction of the Atmospheric Surface Layer: the SFS Stress Model, the Surface Stress Model, and Numerical Friction"

Sara Hughes

In previous analysis we have presented a theory to address a basic difficulty that has plagued large-eddy simulation of turbulent boundary layers: the inability to predict the law-of-the-wall (LOTW) in mean velocity in the surface layer at high Reynolds numbers. Brasseur & Wei (Phys. Fluids 22) developed a theory that explains the source of the difficulty and a framework within which LES can be designed to rectify the problem. The essential difficulty lies in nonphysical frictional content within the discretized dynamical system and the extent to which that frictional content interferes with the inertial scaling that underlies LOTW. Practical models replace inertial flux with dissipative dynamics, so part of this frictional content enters through the subfilter-scale (SFS) model. However, this spurious content also enters through the surface stress model, the structure of the grid and dissipation within the numerical algorithm. I shall review briefly the essential nature of the difficulty and our proposed framework to overcome the error. I shall then discuss accuracy in context with the role of the SFS and surface stress models and prediction of the von Kármán constant, and the consequences of dissipation in the numerical algorithm. To demonstrate the effects we compare spectral LES with finite volume LES of the atmospheric boundary layer and rough-wall turbulent channel flow.

2011

Date

Speaker

Affiliation

Location

Lunch

Title

Chair

Abstract

Oct. 26

Dan Baker

CU/LASP

CG1 South Auditorium

TBD

TBD

Nick Pedatella

 

Nov. 9

Pieter Tans

NOAA/CIRES

ML Main Seminar Room

Chapman room

TBD

Matt Long

link

Nov. 30

George Bryan

NCAR/NESL/MMM

FL2-1022

FL2 1003

A primer on cloud-resolving modeling

Brian Tang

link


2010

Date

Speaker

Affiliation

Location

Lunch

Title

Sept. 8

Jeffrey Kiehl

NCAR/NESL/CGD

ML seminar room

Chapman room

Temporal Characteristics of Earth's Climate System

Oct. 20

Walter Lyons

Sky Fire Productions, Inc.

FL2-1022

FL2-1003

The Electric Sky: Real-Time Detection of Sprite-Producing Lightning

Nov. 10

Hugh Morrison

NCAR/NESL/MMM

FL2-1022

FL2-1003

Representation of microphysics in models (and why it matters...)

2011

Date

Speaker

Affiliation

Location

Lunch

Title

Jan. 12

Rajul Pandya

NCAR/SOARS

FL2-1022

FL2-1003

A Changing Role for Scientists: How to Prepare and Succeed

Feb. 16

T.N. Krishnamurti

Florida State Univ.

FL2-1022

FL2-1003

Dynamics and Prediction of Hurricanes

Mar. 16

Warren Washington

CCR, CGD/NCAR

FL2-1022

FL2-1003

Present and Future Climate Change: The Science, Engineering, and Societal Issues

 

May 19

Frank Eparvier

CU/LASP

CG South Auditorium

CG cafeteria

F10.7 is Not Enough:  What One Year of SDO-EVE Has Taught Us about Solar EUV Irradiance

 

2009 - 2010

Date

Speaker

Affiliation

Location

Title

Sept. 16

Alex Guenther

NCAR/ACD

FL2 1022

Biogenic Volatile Organic Compounds in the Earth System

Oct. 21

Warren Washington

NCAR/CGD

ML Main Seminar Room

20th and 21st Century Climate Change:Computer Modeling,
Societal Impacts, and Environmental Justice

Dec. 9

Howard Bluestein

Univ. of Okla.

FL2 1022

Mobile Doppler Radar Operations During VORTEX-2, Year 1:
Better Living Through Radiation

Jan. 6

Art Richmond

NCAR/HAO

CG1 South

Ionospheric Electrodynamics

Feb. 17

Richard Johnson

CSU

FL2-1022

Impacts of Convection on the Atmospheric Boundary Layer:
Surface Mesohighs and Mesolows

Mar. 17

Greg Holland

NCAR/NESL/MMM

FL2-1022

Climatic Trends and Variability in Atlantic Hurricanes

May 19

Olga Wilhelmi

NCAR/CSAP/GIS/RAL

FL2 1022

Bridging social and geo-sciences data with GIS

2008 - 2009

Date

Speaker

Affiliation

Location

Title

Sept. 17

Xinzhao Chu

CU, CIRES

FL2 1022

Lidar Remote Sensing of Atmosphere and Space: A New Horizon

Oct. 22

Jim Hurrell

NCAR/CDG

FL2 1022

Decadal Climate Prediction: Challenges and Opportunities

Nov. 19

Steve Brown

NOAA

CG1 South Auditorium

Atmospheric Chemistry After Dark

Dec. 3

Harm Jonker

Delft U of Tech

FL Main Seminar Room

Boundary Layer Structure

Jan. 21

Laura Pan

NCAR/ACD

FL2 1022

START08 Experiment: Scientific Concept and Initial Results

Feb. 18

Roger Pielke Jr

CU

ML Main @ 4PM!

Some Uncomfortable Knowledge About Climate Change

Mar. 18

Steve Tomczyk

NCAR/HAO

CG1 South

Solar physics

Apr. 15

David Thompson

CSU

ML Main (Lunch in Chapman Room)

Climate

May 20

Marty Ralph

NOAA

FL2 1022

MMM

June 3

Bruce Vaughn

CU

ML Main (Lunch in Chapman Room)

 

2011/2012 room reservations for seminars and research reviews

How to Run a Seminar

Webcast consent form

Speakers lunch coupon

Committee

If you have questions or comments about the seminar series, please feel free to contact any of the committee members by click on their names below.

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5 Comments

  1. Abstract for Dr. Bluestein's seminar on 9 December 2009:

    The first year of VORTEX-2 (Verification of the Origins of Rotation in Tornadoes EXperiment), a successor to VORTEX-1 conducted 15 years ago, was held in the Plains of the U. S. during the spring of 2009. The main objective of VORTEX-2 is to understand why some supercells produce tornadoes, while others do not. After a brief review of the important physical processes thought to be responsible for tornadogenesis, I will describe why we use mobile Doppler radars to study tornadoes and discuss the successes and failures of the field operations involving the three radars my graduate students, collaborators, and I used.

  2. Abstract for Jan 06 Seminar:

    Ionospheric Electrodynamics
    Arthur D. Richmond
    High Altitude Observatory
    Electric fields and currents play an important role in the dynamics of
    atmosphere above 100 km.  One source of the currents is the dynamo
    effect generated by thermospheric winds that move the conducting medium
    through the geomagnetic field.  Observations of the geomagnetic
    perturbations produced by the ionospheric currents, and of the
    polarization electric fields associated with the currents, provide
    information about the wind system, including atmospheric tides that
    propagate up from lower altitudes.  At high latitudes, interactions
    with the magnetosphere dominate ionospheric electrodynamics, and supply
    major sources of momentum and heat to the thermosphere.  During magnetic
    storms the magnetospheric energy input can disturb the thermosphere and
    ionosphere globally.

  3. Abstract for Greg Holland's seminar on 17 March 2010:

    Climate Trends and Variability in Atlantic Hurricanes
    Greg Holland, Director, NCAR Earth System Laboratory

    Changes in Atlantic hurricane activity on climatic timescales, both from natural variability and anthropogenic impacts, has generated a lot of discussion over recent years. Here I will first outline some of the factors relating to hurricane changes and provide an update on community assessments based on a recently published consensus report from a WMO team. I will follow this with a presentation of recent climate simulations here at NCAR to highlight both the difficulties and pitfalls involved and the multiple approaches that can be adopted. Third will be a general discussion of recent hurricane predictions and issues arising. Finally, I will use an extreme value viewpoint to show how logical it is to expect marked changes in weather extremes in general (hurricanes in particular) with both climate variability and change. Indeed the weather extremes may provide the best bellwether for identifying climate change as it develops.

  4. Abstract for Warren Washington's seminar on March 16, 2011:

    Present and Future Climate Change: The Science, Engineering, and Societal Issues

    The climate has always changed. The most recent assessments have convinced most climate scientists that humankind is changing the earth’s climate and that significant global warming is taking place. Some scientists are skeptical of this view and think the observed changes result from natural climate variability or other causes. A brief review of recently observed 20th century climate change will be presented and compared with climate model simulations. I will also show computer simulations of future climate change from a low carbon emission scenario where the world decides to shift from a fossil fuel based energy strategy to increased conservation, renewables, and possibly nuclear. There will also be a discussion of the scientific uncertainties and societal impacts along with an analysis of policy options including possible geoengineering of the climate system. The broader social science issue of environmental justice will also be discussed.

  5. Abstract for Frank Eparvier's seminar on May 19

    Title: F10.7 is Not Enough:  What One Year of SDO-EVE Has Taught us about Solar EUV Irradiance

    Speaker: Dr. Frank Eparvier, Laboratory for Atmospheric & Space Physics, University of Colorado, Boulder

    Abstract: NASA's Solar Dynamics Observatory (SDO) was launched in early 2010 to observe the Sun with unprecedented spatial, spectral, and temporal resolution.  From the first moment the instruments started started sending data back, we saw things we'd never seen before, from the fluctuations of a quiet Sun to the global nature of solar flares. I will give an overview of the Sun's influence on the Earth, of the SDO mission, and of some of the interesting results we've obtained from the EUV Variability Experiment during the first year of observations.