Staff Notes Daily Calendar Events

Tuesday, December 17, 2019 - 11:00am

Title: Fire, Climate and Humans: A Combustive Combination

Speaker: Natalie Kehrwald, USGS

Date: Tuesday 17 December, 2019

Time: 11 am - 12 pm

*Refreshments at 10:45*

Location: Mesa Lab, Main Seminar Room, ML - 132

Abstact: Humans have accidentally and purposefully been lighting fires for at least one million years. As the past one million years encompasses multiple glacial-interglacial cycles with accompanying vegetation changes, climate has dominated the fire history over this time period, even with the contributions of humans. However, over the past 5000 years, human activity can overwhelm the contribution of climate to regional fire activity. Ice cores from northern Greenland (NEEM; 77°27'N; 51°3.6'W), demonstrate a peak in fire activity centered around ~2500 yr BP. This centennial-scale peak in fire activity is determined from the specific biomarkers levoglucosan, mannosan, and galactosan, which can only be produced by cellulose combustion. Fire data from the JSBACH-Spitfire model over the past 5000 years demonstrates that a climate-only scenario would not increase biomass burning in high northern latitudes for the past 5000 years, while NEEM ice core and regional pollen records demonstrate both increased fire activity and land use change that may be ascribed to human activity. New Zealand sediment cores demonstrate a “burn and bolt” strategy, where small bands of humans were able to deforest ~40% of the South Island within a single century. The arrival of the Māori to New Zealand ~800 yr BP introduced fire to a region with essentially no natural biomass burning. Here, we use fecal sterols in lake sediments to determine when people were in an individual watershed, and establish that the increased presence of Māori in an area corresponds with intensified fire activity. Peaks in fecal sterols and biomass burning occur at a single location for approximately two decades. Fire activity and human presence both drop to almost background levels after this initial burning period but then peak in other regional watersheds, demonstrating the migration of groups of people and associated biomass burning. This human-caused increase in New Zealand fire activity is quantifiable in locations as far away as the EPICA Dome C ice core in East Antarctica (75°06'S; 123°21'E). Due to the specificity of these biomarkers, levoglucosan and its isomers can help differentiate between the deposition of fire aerosols versus fossil fuel combustion products on to the surface of glaciers such as the Juneau Icefield (58° 35' N; 134° 29'W). This combination of specific biomarkers, other proxy data, and model output can help determine the relative impact of humans versus climate factors on regional fire activity.

For more information contact Tracy Baker, tbaker@ucar.edu, 303-497-1366

Type of event:
Seminar/Symposium
Building:
Mesa Lab
Room:
ML-132

Posted by Tracy Baker (tbaker@ucar.edu) at x1366
Hosting lab/division or program:
CGD
Will this event be webcast?
Yes - ML-Main Seminar Room - https://www.ucar.edu/live
Wednesday, January 8, 2020 - 1:00pm

DTC Seminar - Ensemble Post-Processing Using Random Forests

Eric Loken, University of Oklahoma

Wednesday, January 8, 2020 |1:00 – 2:00 PM | FL2 – 1001

Ensembles are important forecast tools because they provide users with uncertainty information. However, ensembles frequently suffer from systematic biases, forecast displacement errors, under-dispersion, and/or sub-optimal reliability. For some areas of prediction, such as severe weather, even convection-allowing ensembles may not be able to explicitly simulate the field of interest (e.g., severe hail or tornadoes), making skillful probabilistic forecasts more difficult to produce. Machine learning techniques, such as the random forest (RF), can improve ensemble-based forecasts during post-processing by non-linearly relating ensemble forecast variables to observed weather.

In this talk, it is demonstrated that a RF can improve next-day (12-36 h) ensemble-derived probabilistic precipitation and severe weather forecasts over the contiguous United States. Unlike previous studies, RFs herein use temporally-aggregated grid-point based ensemble forecasts as predictors. RF forecasts are shown to outperform skillful baselines, such as Gaussian smoothing of raw ensemble probabilities and (for severe weather) updraft helicity-based proxies. Remarkably, RF probabilistic severe weather forecasts derived from Storm Scale Ensemble of Opportunity (SSEO) output also outperform corresponding Storm Prediction Center human forecasts. Overall, results suggest that RFs represent valuable ensemble post-processing tools that enhance forecast reliability and resolution while reducing displacement errors. The RF approach performs best for convection-parameterizing ensembles and more common weather events. It also benefits severe weather forecasts more than precipitation forecasts, presumably since severe weather cannot be explicitly simulated. Promisingly, the RF technique is inexpensive to run in real-time (after training) and requires less than a year of training data to attain a high degree of skill.

 

 

Type of event:
Seminar/Symposium
Building:
FL2
Room:
1001

Posted by Jenny Bolton (jbolton@ucar.edu) at x2852
Hosting lab/division or program:
DTC
Will this event be webcast?
Wednesday, December 18, 2019 - 2:00pm

Rocket Induced High Altitude Acoustic Waves

Presented is a study of rocket induced infrasonic waves that propagate vertically in the thermosphere.  Observations of plasma displacements, changes in radio wave propagation direction and changes in received signal strength are made with a vertical incidence high frequency ionospheric radar.  The primary objectives of this research is to understand the speed at which the infrasonic waves propagate, how the atmosphere behaves in the presence of infrasonic waves and how radio propagation is effected by infrasonic waves.

Rocket-induced infrasonic waves can be reliably detected in the lower thermosphere, they propagate near the adiabatic speed of sound in the lower atmosphere and accelerate rapidly as they approach the altitude of peak plasma density in the ionosphere.  These infrasonic waves are observed to reduce radio wave absorption in the D-region of the ionosphere, modulate the radio wave propagation path when they are near the E-region peak, and modulate both the radio wave propagation path and absorption when they are in the F-region.  In the F-region they are also found to cause geomagnetic pulsations in the form of shear Alfven waves, and cause range variations in ionosonde echoes which can result in ionogram deformations.

Type of event:
Seminar/Symposium
Building:
CG1
Room:
2126

Posted by Sheryl Shapiro (sheryls@ucar.edu) at x1567
Hosting lab/division or program:
HAO
Will this event be webcast?
Tuesday, December 17, 2019 - 9:00am

Every month, a TIAA representative is on-site to meet with employees on an individual basis to answer questions about the TIAA retirement plan and provide guidance with retirement portfolios.

Session with Rhett Belcher:

12/17/2019 – FL2-1002

Register Today: Click here to schedule an appointment with TIAA in December or call their Scheduling and Service Group phone reservation center at: 1-800-732-8353.

These sessions are in high demand, so if you have to miss your appointment, be sure to contact TIAA as soon as possible so they can fill your time slot.

Type of event:
Wellness/Benefits
Building:
FL2
Room:
1002

Posted by Laurie Carr (lcarr@ucar.edu) at x8702
Hosting lab/division or program:
Human Resources
Will this event be webcast?
No
Tuesday, January 7, 2020 - 6:00pm

UCAR Game Night is a recurring event for UCAR/NCAR staff and their family members.  It is currently running every other Tuesday night.  It is a time to come together, have fun, chat and play games.

Game nights will be scheduled using Google Calendar and this group will comprise the invite list as well as be the conduit for various information. The location of Game Nights will rotate between FL2, CG1, and ML cafeterias. Join the Google Group.

UCAR Game Night Policy Information: 

  • UCAR Staff and their family members and friends are welcome at UCAR Game Night. Friends and Family are escorted by a member of UCAR staff at all times.
  • No Alcohol at UCAR Game Nights.
  • No Gambling for real money or other tangible assets. (Some board games include gambling as part of their mechanics and is for “in-game” assets. This is allowed.)
  • You may bring your own food.  It is your responsibility to clean up after yourself.  Please also be respectful of the games and aware of food residue that may be on your hands.
  • Please no open top beverage containers on game tables.
  • You are allowed and encouraged to bring games of your own.
  • UCAR is not responsible for loss or damage of your personal game.
  • Please be aware of the appropriateness of a game you may bring for a workplace event.  (As an example, we would not consider Cards Against Humanity appropriate for the workplace)
  • Have fun!

Posted by Ellen Thomas (ellent@ucar.edu) at x2604
Hosting lab/division or program:
EAC - Employee Activities Committee
Tuesday, January 21, 2020 - 6:00pm

UCAR Game Night is a recurring event for UCAR/NCAR staff and their family members.  It is currently running every other Tuesday night.  It is a time to come together, have fun, chat and play games.

Game nights will be scheduled using Google Calendar and this group will comprise the invite list as well as be the conduit for various information. The location of Game Nights will rotate between FL2, CG1, and ML cafeterias. Join the Google Group.

UCAR Game Night Policy Information: 

  • UCAR Staff and their family members and friends are welcome at UCAR Game Night. Friends and Family are escorted by a member of UCAR staff at all times.
  • No Alcohol at UCAR Game Nights.
  • No Gambling for real money or other tangible assets. (Some board games include gambling as part of their mechanics and is for “in-game” assets. This is allowed.)
  • You may bring your own food.  It is your responsibility to clean up after yourself.  Please also be respectful of the games and aware of food residue that may be on your hands.
  • Please no open top beverage containers on game tables.
  • You are allowed and encouraged to bring games of your own.
  • UCAR is not responsible for loss or damage of your personal game.
  • Please be aware of the appropriateness of a game you may bring for a workplace event.  (As an example, we would not consider Cards Against Humanity appropriate for the workplace)
  • Have fun!

Posted by Ellen Thomas (ellent@ucar.edu) at x2604
Hosting lab/division or program:
EAC - Employee Activities Committee
Tuesday, February 4, 2020 - 6:00pm

UCAR Game Night is a recurring event for UCAR/NCAR staff and their family members.  It is currently running every other Tuesday night.  It is a time to come together, have fun, chat and play games.

Game nights will be scheduled using Google Calendar and this group will comprise the invite list as well as be the conduit for various information. The location of Game Nights will rotate between FL2, CG1, and ML cafeterias. Join the Google Group.

UCAR Game Night Policy Information: 

  • UCAR Staff and their family members and friends are welcome at UCAR Game Night. Friends and Family are escorted by a member of UCAR staff at all times.
  • No Alcohol at UCAR Game Nights.
  • No Gambling for real money or other tangible assets. (Some board games include gambling as part of their mechanics and is for “in-game” assets. This is allowed.)
  • You may bring your own food.  It is your responsibility to clean up after yourself.  Please also be respectful of the games and aware of food residue that may be on your hands.
  • Please no open top beverage containers on game tables.
  • You are allowed and encouraged to bring games of your own.
  • UCAR is not responsible for loss or damage of your personal game.
  • Please be aware of the appropriateness of a game you may bring for a workplace event.  (As an example, we would not consider Cards Against Humanity appropriate for the workplace)
  • Have fun!

Posted by Ellen Thomas (ellent@ucar.edu) at x2604
Hosting lab/division or program:
EAC - Employee Activities Committee
Tuesday, February 18, 2020 - 6:00pm

UCAR Game Night is a recurring event for UCAR/NCAR staff and their family members.  It is currently running every other Tuesday night.  It is a time to come together, have fun, chat and play games.

Game nights will be scheduled using Google Calendar and this group will comprise the invite list as well as be the conduit for various information. The location of Game Nights will rotate between FL2, CG1, and ML cafeterias. Join the Google Group.

UCAR Game Night Policy Information: 

  • UCAR Staff and their family members and friends are welcome at UCAR Game Night. Friends and Family are escorted by a member of UCAR staff at all times.
  • No Alcohol at UCAR Game Nights.
  • No Gambling for real money or other tangible assets. (Some board games include gambling as part of their mechanics and is for “in-game” assets. This is allowed.)
  • You may bring your own food.  It is your responsibility to clean up after yourself.  Please also be respectful of the games and aware of food residue that may be on your hands.
  • Please no open top beverage containers on game tables.
  • You are allowed and encouraged to bring games of your own.
  • UCAR is not responsible for loss or damage of your personal game.
  • Please be aware of the appropriateness of a game you may bring for a workplace event.  (As an example, we would not consider Cards Against Humanity appropriate for the workplace)
  • Have fun!

Posted by Ellen Thomas (ellent@ucar.edu) at x2604
Hosting lab/division or program:
EAC - Employee Activities Committee
Tuesday, March 3, 2020 - 6:00pm

UCAR Game Night is a recurring event for UCAR/NCAR staff and their family members.  It is currently running every other Tuesday night.  It is a time to come together, have fun, chat and play games.

Game nights will be scheduled using Google Calendar and this group will comprise the invite list as well as be the conduit for various information. The location of Game Nights will rotate between FL2, CG1, and ML cafeterias. Join the Google Group.

UCAR Game Night Policy Information: 

  • UCAR Staff and their family members and friends are welcome at UCAR Game Night. Friends and Family are escorted by a member of UCAR staff at all times.
  • No Alcohol at UCAR Game Nights.
  • No Gambling for real money or other tangible assets. (Some board games include gambling as part of their mechanics and is for “in-game” assets. This is allowed.)
  • You may bring your own food.  It is your responsibility to clean up after yourself.  Please also be respectful of the games and aware of food residue that may be on your hands.
  • Please no open top beverage containers on game tables.
  • You are allowed and encouraged to bring games of your own.
  • UCAR is not responsible for loss or damage of your personal game.
  • Please be aware of the appropriateness of a game you may bring for a workplace event.  (As an example, we would not consider Cards Against Humanity appropriate for the workplace)
  • Have fun!

Posted by Ellen Thomas (ellent@ucar.edu) at x2604
Hosting lab/division or program:
EAC - Employee Activities Committee

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