Staff Notes Daily Calendar Events

Tuesday, March 17, 2015 - 11:00am

The radiative forcing from aviation is investigated by using a comprehensive general circulation model in the present (2006) and the future (2050). Global flight distance is projected to increase by a factor of 4 between 2006 and 2050. However, simulated contrail cirrus radiative forcing can increase by a factor of 7, implying that contrail radiative forcing in 2050 is still a small perturbation and far from being saturated.

There is a negative radiative forcing induced by the indirect effect of aviation sulfate aerosols on liquid clouds that increases by a factor of 4 in 2050, and continues to result in a net cooling when all aviation emissions are taken into account. Aviation sulfates emitted at cruise altitude can be transported down to the lowest troposphere where the aerosol concentration is thus increased, thus increasing the cloud drop number concentration and persistence of low-level clouds. Aviation black carbon aerosols produce a negligible forcing.

Presenter(s):
Jack Chen
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, March 9, 2015 - 10:00am

Date/Time:    March 9, 10am-12pm                   
Location: FL1-EOL Atrium

What diversity efforts are going on in UCAR/NCAR?  What is the future of diversity at UCAR/NCAR?
Who are the groups involved in promoting diversity? Stop by to learn more. 

Food and drink will be provided at this special event.

Invited Speakers: 

Carolyn Brinkworth, NCAR Director of Diversity, Education and Outreach
Maria Isquierdo, UCAR Human Resources
Members of Comunidad LatinA de NCAR (CLAN)

Moderated by:

Astrid Maute/Women Organizing Research and Leading Science (WORLS)
Vidal Salazar/Comunidad LatinA de NCAR (CLAN)

Hosted by:  NCAR Diversity Committee, Asian Circle, WORLS, and CLAN

https://ncar.ucar.edu/diversity-committee/diversity-groups-at-ncar

Presenter(s):
Carolyn Brinkworth (NCAR/DEO), Maria Isquierdo (UCAR/HR)
Type of event:
No event type category
Building:
FL1
Room:
EOL Atrium

Posted by Astrid Maute (maute@ucar.edu) at x1539
Lab/division hosting the event:
NCAR, Diversity Talks
Affiliation or organization:
Friday, May 1, 2015 - 11:00am

Local non-profits will visit to promote opportunities for employees and their families to volunteer in our community.

Presenter(s):
EAC
Type of event:
Public Outreach
Building:
FL2
Room:
1001, 1002, 1022, cafeteria atrium

Posted by Jo Zoetewey (zoetewey@ucar.edu) at x2709
Lab/division hosting the event:
UCAR
Affiliation or organization:
Tuesday, March 3, 2015 - 3:30pm

Development of low-cost laser remote sensor for high vertical resolution and continuous measurements of atmospheric water vapor

Scott Spuler

Remote Sensing Facility
Earth Observing Laboratory

The distribution of water vapor influences dynamical and physical processes that drive weather phenomena, general circulation patterns, radiative transfer, and the global water cycle. Terrestrial boundary layers can be especially complex given the large amplitude of diurnal cycles and surface exchange complexities. A better understanding of the spatial and temporal distribution of water vapor is required to support research, and to improve high impact weather forecasts of quantitative precipitation and damaging winds.

While surface observations abound, vertical profiles of water vapor are largely limited to radiosonde data, which are far too sparse, temporally and spatially, to adequately serve planetary boundary layer research. Laser remote sensing instruments are capable of high vertical resolution and continuous measurements; however, they are traditionally expensive devices to develop and operate. The instrument plus its operational cost is especially relevant since multiple devices – a network of profilers – are required to obtain adequate horizontal spatial resolution. Research applications generally require short term deployments of a regional scale network, whereas National Weather Service and related national forecasts require national networks. For example, in the continental USA, high-resolution vertical profiles of humidity at roughly 400 locations are required. Therefore, a new generation of ‘lower cost’ laser remote sensors – capable of safely, accurately, continuously, and autonomously measuring water vapor in the lower troposphere with high vertical resolution – are needed to lower the barrier to investment.

This seminar discusses the development and testing of a next generation laser remote profiler for water vapor which has the potential to enable a regional and national scale network. The electrically-pumped semiconductor-based laser transmitter is inherently low-maintenance, low-cost, and designed to be eye-safe at the exit port. It has the characteristics necessary for the differential absorption lidar technique; rapid frequency agility with good spectral purity, and when combined with ultra-narrowband multistage optical filters in the receiver, the system provides continuous profiles of water vapor with complete coverage – including periods of bright clouds – from 300 m above ground level to 4 km (or cloud base, whichever comes first) with 150 m nominal vertical resolution and 1 minute temporal resolution. Results from the initial field test in 2014, which includes inter-comparisons with radiosondes and an infrared radiometer, will be discussed. This ‘lower cost’ lidar design may be a significant step towards improving our understanding of the distribution of atmospheric water vapor.

Tuesday, 3 March 2015, 3:30PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg. 2 Large Auditorium (Rm 1022)

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

Presenter(s):
Scott Spuler
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, RSF
Affiliation or organization:
Tuesday, March 10, 2015 - 11:00am

The Madden-Julian oscillation is the dominant mode of tropical intraseasonal variability, but its dynamics remain poorly understood. In this talk I will argue that the MJO is a large-scale example of convective self-aggregation. Non-rotating simulations with globally uniform boundary conditions using the super-parameterized CAM show that convection self-organizes into large (~4000km) clusters surrounded by dry regions. A moist static energy budget indicates the aggregation is driven by diabatic feedbacks, particularly cloud-longwave interaction. When rotation is restored, the model simulates a robust MJO, and mechanism denial experiments confirm the importance of longwave heating to both aggregation and the MJO. Non-rotating simulations using a conventional model with a weak MJO show a much weaker tendency to aggregate.

Small-scale aggregation in cloud-resolving models has been found to occur more readily at high temperatures, suggesting a similar dependence for the MJO. Two sets of warming experiments appear to confirm this idea, with large increases in MJO activity in response to increased SST. Moist static energy budgets suggest the stronger MJO is driven by vertical MSE advection, which becomes increasingly destabilizing at high temperatures.

Presenter(s):
Nathan Arnold
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, March 9, 2015 - 12:00pm
Abstract:

Earth's ionosphere presents a threat to human activities such as satellite positioning and timing, radio communications and surveillance. Nowcasts and forecasts of the ionosphere could help mitigate these damaging effects. Recent advances in the field of ionospheric imaging and new storm-time ionospheric forecasting techniques are presented here. The approach combines Total Electron Content (TEC) measurements with an ensemble of coupled thermosphere-ionosphere models to produce short-term forecasts during a storm. A review of ionospheric physics will also be given. The relationship between data assimilation and forecasting is explored with reference to the physics of the thermosphere-ionosphere system. An important conclusion of this work is that thermospheric composition can be inferred from measurements of ionospheric Total Electron Content (TEC). Future directions, including the inference of Solar and geomagnetic drivers and coupling with lower-atmospheric models will be discussed. 

Presenter(s):
Alex Chartier
Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
Damon Room

Posted by Carolyn Mueller (cmueller@ucar.edu) at x2491
Lab/division hosting the event:
NCAR, CISL, IMAGe
Wednesday, March 11, 2015 - 3:30pm

Speaker:  Jenny Sun, Scientist, RAL, HAP
                
Date:       March 11, 2015    
Time:       3:30pm
Place:       FL 2 – Rm 1022

Abstract:

The great Colorado flood that occurred during the second week of September 2013 was an unprecedented event causing loss of life and significant property damage. While the rainfall and flooding covered a large area of northern Colorado over a one-week period, three episodes of heavy rainfall deluged the Front Range of the Rocky Mountains with the most intense episode centered in Boulder County the night of 11 September. The large-scale event brought abundant moisture from the Gulf of Mexico which is believed to be the source of the record amount of rainfall. Locally heavy rainfall, however, was driven by mesoscale processes.  This study will examine the formation mechanisms of these processes on the night of 11 September using high-resolution analyses from the Variational Doppler Radar Analysis System (VDRAS). VDRAS performs fine-scale analyses by assimilating observations from several WSR-88D radars along the Front Range region and surface networks using a 4-dimensional data assimilation technique. Results suggest that, in addition to the large-scale forcing over the Rocky Mountains, the terrain of the Palmer Divide south of Denver and the Cheyenne Ridge north of Boulder played an important role in the formation of the mesoscale heavy rainfall system.

This seminar will be Webcast - Webcast link 
http://www.fin.ucar.edu/it/mms/fl-live.htm

Presenter(s):
Jenny Sun
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022

Posted by Marybeth Zarlingo (zarlingo@ucar.edu) at x2751
Lab/division hosting the event:
NCAR, RAL, HAP
Affiliation or organization:
Friday, March 6, 2015 - 9:00am

UCAR FY15 Health & Benefits Fair
Friday, March 6, 2015
9:00 am - 1:00 pm
CG1-Auditorium
No registration required

Health Fair events include:  Blood Screening Results and Private Consultations; Blood Pressure Screening, Full Blood Chemistry, PSA Prostate Cancer Screening; Optional Blood Screening Screenings; Pulmonary Screening; Bone Density Screening; Body Mass Analysis; Skin Cancer Screening; Vision/Hearing Screening; Ergonomics; Child and Elder Care Resources; Benefits Information; Chair Massage; Health Information Booths, Refreshments, Giveaways; Prizes; and much, much more!

UCAR offers these events as a service and participation is voluntary.  UCAR does not recommend or endorse any products, services or resources associated with these events. For more information, visit UCAR's Health & Benefits Fair website.

Here's to your good health from your friends on the Wellness Advisory Committee (WAC).

Presenter(s):
Health Promotions Management
Type of event:
Wellness/Benefits
Building:
CG1
Room:
Auditorium

Posted by Cheryl Cristanelli (cherylc@ucar.edu) at x8708
Lab/division hosting the event:
UCAR, F&A
Affiliation or organization:
Thursday, March 5, 2015 - 3:30pm

Mesoscale and Microscale Meteorology/Cloud Physics Across Scales Seminar

Wojciech W. Grabowski
National Center for Atmospheric Research
Boulder, Colorado

Formation and growth of cloud and precipitation particles (“cloud microphysics”) affect cloud dynamics and such macroscopic cloud field properties as the mean surface rainfall, cloud cover, and liquid/ice water paths. Traditional approaches to investigate the impacts rely on parallel simulations with different microphysical schemes or with the same scheme with different parameters. Such methodologies are not reliable because of the natural variability of the cloud field that is affected by the feedback between cloud microphysics and dynamics. We developed a novel modeling methodology to assess the impact of cloud microphysics on cloud dynamics and on simulated macroscopic cloud field characteristics. The main idea is to use two sets of thermodynamic variables driven by two microphysical schemes (or by the same scheme with different parameters), with one set coupled to the dynamics and driving the simulation, and the other set piggybacking the simulation, that is, responding to the simulated flow but not affecting it. We will discuss application of this methodology to cloud field simulations of shallow and deep convection. We will show that the methodology allows assessing the impact of cloud microphysics on cloud field properties with unprecedented accuracy. By switching the sets (i.e., the set driving the simulation becomes the piggybacking one, and vice versa), the impact on cloud dynamics can be isolated from purely microphysical effects. We will show that the new methodology documents a rather insignificant impact of the assumed cloud droplet concentration on convective dynamics for the case of scattered unorganized deep convection. These results cast doubt on the dynamic basis of the deep-convection invigoration in polluted environments.

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

Recorded seminar link can be viewed here:
https://www.mmm.ucar.edu/events/seminars

Thursday, 5 March 2015, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Main Auditorium, Room 1022

Presenter(s):
Wojciech W. Grabowski
Type of event:
Seminar/Symposium
Building:
FL2
Room:
1022

Posted by Michelle Menard (menard@ucar.edu) at x8189
Lab/division hosting the event:
NCAR, MMM
Affiliation or organization: