Staff Notes Daily Calendar Events

Tuesday, August 26, 2014 - 11:00am

Speaker:     Bob Gall, Development Manager of HFIP, NOAA
Date:          August 26, 2014
Time:          11:00am
Place:          FL 2 – Room 1001

Abstract:

The Hurricane Forecast Improvement Program (HFIP) has goals to reduce the error in track and intensity forecast guidance from numerical model systems by 20% in five years (by 2014) and 50% in ten years. Additional goals include skillful seven-day forecasts and a greatly increased ability to forecast rapid intensification and decay. To meet these goals by the deadlines the HFIP has organized a large component of the hurricane community to focus on various aspects of development of the numerical and statistical model forecast guidance systems expected to lead to these improvements. This includes development of advanced data assimilation systems and ensemble systems at high resolution for both regional and global models followed by statistical post processing.

HFIP was summarized extensively in a recent Bulletin of the American Meteorological Society article: http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-12-00071.1. In this presentation we will give an overview of the program followed by recent results.

We are nearing the end of the first five years of the HFIP and if the Project is to be successful, some of the research results that it has been working on with NCEP and the community to get into operations ought to be apparent in operational hurricane model results. In this talk we will outline those results and note where we need to focus the effort during the next five years.

Presenter(s):
Bob Gall
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1001

Posted by Marybeth Zarlingo (zarlingo@ucar.edu) at x2751
Lab/division hosting the event:
NCAR, RAL - JNT
Affiliation or organization:
Thursday, August 28, 2014 - 2:00pm

IPCC Chapter: Policymakers/Technical summaries

Ever wonder what the Intergovernmental Panel on Climate Change (IPCC) report says?  Learn more Tuesday and Thursday afternoons this fall during a seminar series by IPCC authors and contributors. This fall’s focus is on Climate Change 2013: The Physical Science Basis (Working Group I’s contribution to the IPCC 5th Assessment Report).

Presenter(s):
Jerry Meehl
Type of event:
Seminar/Symposium
Building:
CIRES Auditorium at CU-Boulder

Posted by Gaylynn Potemkin (potemkin@ucar.edu) at x1618
Lab/division hosting the event:
External:, CIRES-ATOC
Affiliation or organization:
Thursday, August 28, 2014 - 3:30pm

Benjamin Ménétrier
National Center for Atmospheric Research
Mesoscale and Microscale Meteorology Division
Boulder, Colorado

The estimation of forecast error covariances estimation is a key-point to data assimilation (DA) schemes in numerical weather prediction (NWP) systems. For several years, it has been shown that ensemble methods are the most accurate at capturing flow-dependence information. However, their huge computational cost raises a strong limitation to the ensemble size. Consequently, covariances estimated with a small ensemble are contaminated with random sampling error, especially at convective scales. A theory of covariance filtering has been developed in order to remove most of the sampling noise while keeping the signal of interest. It arises from the merging of linear filtering theory and the theory of sample centered moments estimation. Its strength comes from the definition of a criterion for optimal filtering that relies on known
quantities, that are the raw and the filtered sample covariances.

This criterion paves the way for new algorithms and interesting applications for NWP. Two of them are detailed: spatial filtering of variances and covariance localization. The theory is tested with real background error covariances computed using a large Ensemble Data Assimilation (EDA) at convective scale coupled with a corresponding EDA at global scale, based respectively on the AROME and ARPEGE NWP systems operational at METEO-FRANCE. Variance filtering algorithms, both homogeneous and heterogeneous, show very good and consistent results. Localization functions are successfully diagnosed from the ensemble, providing relevant localization length-scales that strongly depend on the number of members, on the meteorological variables and on the vertical levels.

This seminar will be recorded and available via webcast at:

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

Thursday, 28 August 2014, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Main Auditorium, Room 1022

Presenter(s):
Benjamin Ménétrier
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022

Posted by Michelle Menard (menard@ucar.edu) at x8189
Lab/division hosting the event:
NCAR, NESL, MMM
Affiliation or organization:
Tuesday, September 2, 2014 - 3:30pm

Devils and hairpins in the atmospheric surface layer
Steve Oncley
In-Situ Sensing Facility
Earth Observing Laboratory

Vorticies in the atmospheric surface layer passing through a fixed array of 31 turbulence sensors have created a data set with unprecedented resolution of their characteristics and dynamics.  During the day, these vorticies likely are dust devils, though no visual observations are available to confirm this.  At night, this array appears to have made the first field observations of hairpin vorticies.  This talk will describe the structure and dynamics of several types of vorticies and relate them to other vortex investigations, including tornadoes and hurricanes.

Tuesday, 2 September 2014, 3:30PM
NCAR - Foothills Laboratory
3450 Mitchell Lane
FL2 Large Auditorium (FL2-1022)

Presenter(s):
Steve Oncley
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022 (Large Auditorium)

Posted by Whitney Robinson (wrobs@ucar.edu) at x8713
Lab/division hosting the event:
NCAR, EOL, ISF
Affiliation or organization:
Thursday, September 4, 2014 - 3:30pm

Sylwester Arabas
University of Warsaw
Poland

Two newly developed reusable software components applicable to atmospheric modelling will be introduced during the talk. The two projects named libmpdata++ and libcloudph++ are implemented as C++ libraries and are released as free and open-source software. Both are designed with maintainability, researchers productivity and result reproducibility as priorities.

The libmpdata++ is an implementation of a family of advective transport solvers based on the Multidimensional Positive Definite Advection Transport Algorithm (MPDATA). It covers the basic second-order-accurate formulation of MPDATA, its third-order variant, the infinite-gauge option for variable-sign fields, and a flux-corrected transport extension to guarantee non-oscillatory solutions. In the current release, the solvers offer integration in up to three spatial dimensions and parallelisation through domain decomposition using shared memory. The second library - libcloudph++ - is a collection of algorithms for representing cloud microphysics in numerical models. It is intended for models of different dimensionality and complexity, ranging from simple zero-dimensional parcel frameworks to complex cloud-resolving (e.g. large-eddy) simulations. In the current release, the library covers three warm-rain schemes: a single-moment bulk scheme, a double-moment scheme and a particle-based scheme featuring the ``Super Droplet'' Monte-Carlo coalescence algorithm. The particle-based scheme is implemented for execution on both CPU[s] and GPU.

Simulations of aerosol-cloud interactions performed using a model based on libmpdata++ and libcloudph++ will be presented.

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

Thursday, 4 September 2014, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Main Auditorium, Room 1022

Presenter(s):
Sylwester Arabas
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022

Posted by Michelle Menard (menard@ucar.edu) at x8189
Lab/division hosting the event:
NCAR, NESL, MMM
Affiliation or organization:
Thursday, September 4, 2014 - 3:30pm

In the mass-weighted isentropic zonal mean (MIM), the meridional circulation reveals the
strong extratropical direct (ETD) circulation. Its complete lower boundary value formulation
allows us to analyze the angular momentum balance and energy conversions associated with
the ETD circulation. The ETD circulation indicates the generation of the polar cold air mass at
higher latitudes and “zonal mean” cold outbreaks at mid-latitudes.


The isentropic analysis is extended to geographical distributions of polar cold air mass, its
horizontal fluxes and its diabatic change below a designated potential temperature. In the NH
winter, the polar cold air mass below q=280K has two distinct main streams: the East Asian
stream and the North American stream. The EA stream grows over the northern part of the
Eurasian continent, flows eastward, turns down toward East Asia, and disappears over the
North Pacific Ocean. The NA stream grows over the Arctic Ocean, flows toward the eastern
coast of North America, and disappears over the North Atlantic Ocean. Concerning the EA
stream, an analysis is made of temporal variations of synoptic forcing to induce cold air
outbreaks.


Finally, the polar cold air mass amounts below q=280K is compared between the NH and SH
winters. The results are analyzed using a two box model composed of the genesis and loss
box. The difference in the polar cold air mass is attributed to the residence time in the
genesis.

Presenter(s):
Dr. Toshiki Iwasaki
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Main Seminar Room

Posted by Gaylynn Potemkin (potemkin@ucar.edu) at x1618
Lab/division hosting the event:
NCAR, CGD
Affiliation or organization:
Monday, September 8, 2014 - 12:00pm

Please plan to attend this brown bag brainstorming session to discuss content and ideas for the new NCAR climate exhibit, which we will be developing over the next year. Bring your great ideas for how we can share information about climate science and climate change with our visitors in this new exhibit.

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

Posted by Becca Hatheway (hatheway@ucar.edu) at x2597
Lab/division hosting the event:
UCAR Community Programs, Spark: UCAR Science Education
Tuesday, September 9, 2014 - 11:00am

As global anthropogenic emissions of greenhouse gases continue to rise, there is
an increasing risk of serious disruptions in ecosystems and society due to global
warming. As a consequence, research on climate engineering (CE) is receiving
growing attention, also among climate scientists (e.g., IPCC AR5). But, even basic
CE research using Earth System Models (ESMs) raises a series of ethical questions
that need to be considered. Also, any CE technique carries a risk of causing serious
side effects, e.g., through disruptions of the hydrological cycle.

Climate engineering can be divided into Greenhouse Gas Removal (GGR) and
Radiation Management (RM). RM here refers to deliberate modifications of either
incoming solar radiation or outgoing terrestrial radiation. We will start by
reviewing the basic principles of proposed RM techniques – stratospheric sulfur
injections, marine sky brightening, cirrus cloud thinning, desert brightening. We
review some robust results concerning precipitation changes that have recently
emerged from multi-model ESM experiments within the Geoengineering Model
Intercomparison Project (GeoMIP). We then demonstrate that the precipitation
changes depend strongly on which RM technique is applied. We show how that
finding can be explained from atmospheric energy budget considerations.

Presenter(s):
Jón Egill Kristjánsson
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Main Seminar Room

Posted by Gaylynn Potemkin (potemkin@ucar.edu) at x1618
Lab/division hosting the event:
NCAR, CGD
Affiliation or organization:
Monday, September 15, 2014 - 12:00pm

Please plan to attend this brown bag brainstorming session to discuss content and ideas for the new NCAR climate exhibit, which we will be developing over the next year. Bring your great ideas for how we can share information about climate science and climate change with our visitors in this new exhibit.

Presenter(s):
Becca Hatheway
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1001

Posted by Becca Hatheway (hatheway@ucar.edu) at x2597
Lab/division hosting the event:
UCAR Community Programs, Spark: UCAR Science Education