Staff Notes Daily Calendar Events

Friday, April 18, 2014 - 11:00am

Abstract:
In 2007, more than half of all the people in the world lived in cities and towns.  By 2030 that statistic is likely to rise to 80 percent.  In an urbanizing world, tropical landscapes will face many demands to produce food and energy crops, protect watersheds and airsheds, and conserve wildlands.  The management of these landscapes affects the ability to mitigate and adapt to climate change.  The presentation will discuss both the opportunities and challenges for tropical land use in an urban world, emphasizing the need to match the scale of analysis with the scale at which decisions about landscapes are made.

Presenter(s):
Ruth DeFries
Type of event:
Seminar/Symposium
Building:
FL2
Room:
Large Auditorium

Posted by Scott Briggs (Email) at x1607
Lab/division hosting the event:
NCAR, ASP
Affiliation or organization:
Tuesday, April 22, 2014 - 3:30pm

Under the pattern scaling approximation the range of possible regional climate change for a particular future period and forcing scenario can be attributed to both the range of global warming for that case and the range of the regional sensitivity or scaled change ‘per degree of warming’. Climate change projections for Australia have used a multi-model ensemble to quantify this response in each variable, with the changes from the different models weighted based on an estimation of likely skill. If more skilful models produce changes that are less diverse, then such weighting can narrow the projected range. To date, skill scores for the present climate have been used for both Australia and all continents. Relationships between scaled change quantities can provide further insights. In particular, the ensemble of values for simulated Australian rainfall change correlates well with a pattern of tropical change that resembles ENSO. Changes in precipitation and temperature over the USA also suggest an influence of mode-like patterns in the future trend fields. As an initial step, the skill of models for the present climate means and variability over the tropics is assessed. The potential for these scores to influence projections is explored.

Seminars are live webcast: http://www.fin.ucar.edu/it/mms/ml-live.htm

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

Posted by Gaylynn Potemkin (Email) at x1618
Lab/division hosting the event:
NCAR, NESL, CGD
Affiliation or organization:
Wednesday, April 23, 2014 - 6:30pm

Pattern scaling was invented by the first author of this paper, and first described in Santer et al. (1990).  The primary motive was to allow a limited number of GCM results to be generalized to cover a wider range of both emissions scenarios and climate model parameters in a computationally efficient way. The underlying assumption of pattern scaling is that the geographical patterns of climate change per unit of global-mean warming are similar, and largely independent of the amount of warming and the details of atmospheric composition changes that lead to this warming. If this assumption is reasonable, then the time-evolving pattern of change for variable “Y” will be given, to a high degree of approximation, by:

      ΔYb(x,t) = ΔTb(t) * [ΔYa(x,t0) / ΔTa(t0)]

 where ΔYa(x,t0) is the pattern of change and ΔTa(t0) is the global-mean temperature change for an experiment with emissions scenario ‘a’ at some time t0, and ΔYb(x,t) and ΔTb(t) are the corresponding terms for emissions scenario ‘b’ at time t. Essentially, emissions scenario ‘a’ is used to define a characteristic standardized pattern of change (i.e., the change per unit global-mean warming) and this is simply scaled up by ΔTb(t) to obtain the pattern at time t for scenario ‘b’. This method, which we call ‘naïve’ pattern scaling, has been used many times subsequent to our original paper. The method works well for forcing that is dominated by long-lived species, such as CO2, where the forcing pattern satisfies the underlying assumption of the method.

 For short-lived species, however, such as sulfate aerosols, the underlying assumption clearly fails. Forcing patterns for such species are closely related to the pattern of emissions, which have changed in the past and are projected to change markedly over space and time in the future. These changes in emissions and forcing lead to spatio-temporal changes in climate response patterns. This is particularly important for SO2 emissions and sulfate aerosol forcing. Over the past four decades, the pattern of SO2 emissions has shifted dramatically from peak emissions over North America and Europe to maximum emissions over eastern Asia. A method for accounting for these changes was developed in the mid 1990s, and has been implemented since then in various versions of the MAGICC/SCENGEN climate model software (http://www.cgd.ucar.edu/cas/wigley/magicc/index.html).  The method divides emissions into long-lived species with a single characteristic response pattern, and short-lived species with time-varying response patterns. The latter in turn are determined by dividing the globe into three primary emissions regions, each of which has a characteristic response pattern. The total response pattern is determined by a linear combination of the three regional patterns, with time-varying weights that are related to the time-varying emissions in the three regions. In this paper we describe the method in more detail and present illustrative results.

    

Santer, B.D., Wigley, T.M.L., Schlesinger, M.E. and Mitchell, J.F.B., 1990:  Developing Climate Scenarios from Equilibrium GCM Results. Max-Planck-Institut für Meteorologie Report No. 47, Hamburg, Germany, 29 pp.

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

Posted by Carolyn Mueller (Email) at x2491
Lab/division hosting the event:
NCAR, CISL/IMAGe
Thursday, April 24, 2014 - 12:00pm

Local non-profits will visit to promote opportunities for employees and their families to volunteer in our community.  This event runs Thursday April 24th from 12P - 6P.

Presenter(s):
EAC
Type of event:
Public Outreach
Building:
CG2
Room:
Auditorium

Posted by Jo Zoetewey (Email) at x2709
Lab/division hosting the event:
UCAR, EAC
Affiliation or organization:
Thursday, April 24, 2014 - 3:30pm

Russ Schumacher
Colorado State University
Department of Atmospheric Science


Extreme precipitation in the warm season can result from a variety of weather systems, but most such events in the U.S. occur in association with elevated convective systems, in which the unstable air feeding the convection originates above the surface. These events also tend to be poorly predicted by numerical weather prediction models. This presentation will look at past and possible future research directions for both surface-based and elevated mesoscale convective systems (MCSs). Then, the synoptic- and mesoscale processes responsible for the maintenance of elevated, heavy-rain-producing MCSs will be discussed from the perspectives of both traditional composite analysis and a principal component analysis-based method. Quasi-idealized simulations, which incorporate either the mesoscale ascent, or the full three-dimensional variability, in elevated MCS environments, are used to address the respective roles of large-scale forcing for ascent, convectively generated cold pools, and convectively generated gravity waves. Using ensembles of forecasts, we explore the key sensitivities in rainfall amounts to initial conditions and physical processes, and hypotheses identified from the ensemble-based analyses are then tested in a more idealized framework. Finally, remaining limitations in understanding and prediction, along with plans for addressing them in the upcoming Plains Elevated Convection At Night (PECAN) field experiment, will be discussed.


This seminar will be recorded and available via webcast at:
http://www.fin.ucar.edu/it/mms/fl2-live.htm

Thursday, 24 April 2014, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Small Seminar Room 1001

Presenter(s):
Russ Schumacher
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1001

Posted by Michelle Menard (Email) at x8189
Lab/division hosting the event:
NCAR, NESL, MMM
Affiliation or organization:
Wednesday, May 21, 2014 - 3:00pm

This talk will be webcast and recorded

http://www.fin.ucar.edu/it/mms/ml-live.htm

By the Clean Air Act, the U.S. Environmental Protection Agency (US EPA) is required to monitor, regulate and set national ambient air quality standards (NAAQS) for ozone along with other pollutants considered to be harmful to public health and the environment. To investigate ozone exposure, the EPA utilizes monitoring devices sparsely located across the United States along with estimates of gridded ground-level ozone concentration produced by a deterministic numerical air quality model, Models-3/Community Mesoscale Air Quality Model, CMAQ CMAQ. To investigate about the exceedance behavior of ozone relative to the NAAQS which is given in terms of the level of the annual fourth highest ozone concentration, we propose a downscaling modeling approach that employs a spatial fourth highest extreme value (FHEV) model to assimilate both data sources. In particular, the FHEV incorporates spatially-varying parameters that depend on a smoothed CMAQ output. We apply our approach to the annual fourth highest ozone concentration in the Eastern United States during years 2001-2008 and obtain an improved predictive performance compared to that of other downscaler models.

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

Posted by Carolyn Mueller (Email) at x2491
Lab/division hosting the event:
NCAR, CISL, IMAGe
Affiliation or organization:
Tuesday, June 3, 2014 - 3:30pm

There is a perception that no climate model has simulated the recent plateau of global warming that started around 2000.  This warming slow-down is commonly referred to as the “early-2000s hiatus”.  Though the multi-model ensemble average of uninitialized climate models indeed shows early-21st century warming greater than what has been observed, there are a number of individual ensemble members from several models that did actually simulate the early-2000s hiatus.  Those simulations were successful because the internally generated naturally occurring climate variability associated with the negative phase of the Interdecadal Pacific Oscillation (IPO) happened, by chance, to coincide with the observed negative phase of the IPO that contributed to the early-2000s hiatus.  However, picking out those skillful ensemble members in advance would not have been possible in the 1990s prior to the hiatus, and thus would have had no predictive value.  If the recently developed methodology of initialized decadal climate prediction could have been applied in the 1990s, both the negative phase of the IPO in the early 2000s as well as the hiatus could have been predicted.  The processes associated with this skillful prediction include more heat being mixed into the subsurface ocean as indicated by positive (downward)  net surface heat flux over the global ocean, and stronger Pacific trade winds that intensify the Pacific Ocean subtropical cells and mix more heat into the subsurface ocean.

Seminars are live webcast: http://www.fin.ucar.edu/it/mms/ml-live.htm

Presenter(s):
Gerald A. Meehl
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Main Seminar Room

Posted by Gaylynn Potemkin (Email) at x1618
Lab/division hosting the event:
NCAR, NESL, CGD
Affiliation or organization:
Monday, June 23, 2014 - 1:30pm

The 15th Annual WRF users' event will take place at NCAR's Center Green Campus, Boulder, Colorado, on 23 - 27 June 2014.

23 June (1:30 p.m. to 5:00 p.m.):Best Practices for Applying WRF, WRF-DA and WRF-Chem
24-26 June: The 15th WRF Users' Workshop
27 June (Friday morning):  Instructional Sessions (WRF- Hydro, MPAS, LAPS, IDV, NCL, VAPOR)

Presenter(s):
Assorted NCAR Staff
Type of event:
Workshop
Building:
CG1
Room:
Auditorium

Posted by Kris Marwitz (Email) at x8198
Lab/division hosting the event:
NCAR, NESL, MMM
Affiliation or organization: