Staff Notes Daily Announcements

Progress and Prospects of Advanced Radar Refractivity Retrieval 

Ya-Chien Feng
McGill University 

Radar refractivity is a proxy for two dimensional near-surface moisture fields and can be retrieved within about a 50-km radius of radars. This technique is based on the temporal phase variation from ground targets as an indication of the refractivity change along the radar beam path. Refractivity is most sensitive to moisture variations near the ground. High temporal and spatial resolution refractivity maps have been previously used to study the spatial variation of near-surface moisture associated with convection evolution and boundary layer processes, as well as for assimilation in numerical weather prediction models to improve quantitative precipitation forecasting skills. However, data quality concerns regarding the representativeness of the refractivity maps, simplified assumptions of the retrieval method, and unknown error quantification have limited the applications in recent years. This presentation will introduce recent progress in the development of radar refractivity retrieval algorithms. Three-dimensional refractivity information is provided, consisting of a horizontal map at a given height above the terrain and the averaged refractivity profile over the data coverage. The temporal evolution of the refractivity profile captures the diurnal mixing conditions within the lowest levels of the atmosphere. The observational bias and error of the retrieved refractivity fields are quantified based on an improved understanding of the fundamental characteristics of ground targets and the uncertainties of the phase measurements as well as the retrieval. The knowledge of the error of the retrieved product is essential both for data assimilation and future technique improvements. The operational WSR-88D radar network may someday implement the advanced refractivity retrieval technique. This could advance the understanding of the moisture distribution associated with heterogeneous land surfaces, such as urban-rural contrast, and it might help improve the initialization of near-surface thermodynamic conditions for models at various resolutions.

Semiar will be webcast at:

Tuesday 02, May, 2017 3:30 PM
NCAR Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Large Auditorium (RM1022)

Posted by Meghan Stell at ext. 2043,

Friday, April 28, 2017 to Tuesday, May 2, 2017

Air Quality in the Northern Colorado Front Range: FRAPPÉ and DISCOVER-AQ Campaigns

Gabi Pfister

Two large air quality studies involving four aircraft and extensive ground based measurements were conducted in the Northern Colorado Front Range in the summer of 2014: the NCAR/NSF/State of Colorado Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) and the 4th deployment of the NASA DISCOVER-AQ. The immensely rich data set from these campaigns is analyzed to characterize the driver of high ozone pollution in the Front Range. This is a complex task given the large variety of emission sources (urban emissions with the addition of a rapidly expanding oil and natural gas sector, industry and power generation units as well as animal feedlots), the complex topography and the influence of upwind pollution and poses a large challenge to atmospheric models. 

Detailed chemical and meteorological observations during these five weeks were collected from a range of platforms including aircraft, surface sites, mobile vans, lidars, wind profilers, ozone sondes and satellites. All these have different coverage in time and space and measure different sets of parameters. In order to fully exploit the data set, there is a need and an opportunity for statistical techniques to optimally integrate the different data sets and develop ways to efficiently and conclusively compare to model output.

Wednesday, May 31st, 2017

12:00pm - 1:00pm

Mesa Lab, Chapman Room 

(Bring your lunch)

Posted by Michelle Patton at ext. 1253,

Thursday, April 27, 2017 to Wednesday, May 31, 2017

These new acquisitions will be displayed at each NCAR Library location for one week, first at FL Library and then at ML Library. If you have questions regarding the items or want to suggest additions to the library collection, please contact the NCAR Library at or ext. 8505.

Atribution of Extreme Weather Events in the Context of Climate Change
Publisher: National Academies of Science Engineering and Medicine
Location: FL Library
Call Number: QC 981.8 .C53 N38 2016

Spectral and High Order Methods for Partial Differential Equations, ICOSAHOM 2014
Editors: Barth and Others
Publisher: Springer
Location: ML Library
Call Number: QA 377 .I583 2014

R for Data Science
Authors:: Wickham and Grolemund
Publisher: O'Reilly
Location: ML Library
Call Number: QA 276.45 .R3 W53 2016

Early Humans
Author: Nicholas Ashton
Publisher: William Collins
Location: FL Library
Call Number: GF 551 .A829 2017

Astronomical Almanac for the Year 2018
Publisher: Nautical Almanac Office
Location: FL Library
Call Number: REF QB 8 .U6 A77 2018


Posted by NCAR Library at ext. 8505,

Thursday, April 27, 2017 to Wednesday, May 3, 2017

F&A will be hosting a walk-in support session for staff who have questions about the new cellular devices policy and procedures or need assistance with completing the associated forms for transfers and changes. The session will be as follows:

  • FL2-1001 – May 2 – 10:30 am-12:00 noon

Contact: Katrina Kiefer,, x2135.

Posted by Rebecca Swisher at ext. 8609,

Thursday, April 27, 2017 to Tuesday, May 2, 2017

Gravity waves in the global 7-km GEOS-5 Nature Run
Dr. Laura Holt
NorthWest Research Associates

Gravity waves are important drivers of atmospheric motion on both local and global-scales, from the upper troposphere to the thermosphere and ionosphere. However, most global climate models are too coarse to resolve the full spectrum of gravity waves and use gravity wave drag parameterizations to approximate the effects of gravity waves on the circulation. These parameterizations are a large source of uncertainty in models, in part because we do not yet have a global understanding of gravity wave properties and their sources from observations to constrain parameterizations. As computational power increases, atmospheric general circulation models are able to resolve smaller and smaller-scale waves, reducing, but not (yet) eliminating, the need for parameterizations. High-resolution models can also provide guidance for gravity wave drag parameterizations where observations are lacking through investigation of the modeled small-scale waves, their sources, and how they interact with the large-scale circulation. This talk will explore some of the aspects of the resolved small-scale waves in the global 7-km horizontal resolution Goddard Earth Observing System model (GEOS-5) Nature Run. In particular, the talk will focus on the wave driving of the quasi-biennial oscillation in the tropics and nonorographic gravity waves and sources related to convection and frontogenesis in the Southern Hemisphere winter.

Monday, May 1, 2017
3:30 p.m.
Refreshments 3:15 p.m.
NCAR Foothills Laboratory, FL2-1022, Large Auditorium

Live webcast:


Posted by Caitlyn Quinn at ext. 1308,

Wednesday, April 26, 2017 to Monday, May 1, 2017

Register now to join a free National Academies of Sciences, Engineering, and Medicine webinar to explore the themes discussed at the workshop Antarctic Sea Ice Variability in the Southern Ocean-Climate System.

May 4, 2017
2:00 PM EDT - 3:00 PM EDT / noon - 1:00 PM MDT

The workshop focused on the potential mechanisms driving increases in the extent and concentration of the sea ice surrounding Antarctic from the late 1970s until 2015—increases that were not reproduced by climate models, and that came despite the overall warming of the global climate and the region (summarized in the Workshop Proceedings).

The webinar will feature presentations from the chair of the workshop planning committee, Julienne Stroeve of the University of Colorado, Boulder, and from committee members Marika Holland of the National Center for Atmospheric Research, Boulder, and Marilyn Raphael of the University of California, Los Angeles.

Please register to attend:

Posted by Zhenya Gallon at ext. 8607,

Wednesday, April 26, 2017 to Thursday, May 4, 2017

Posted by Annette Lampert at ext. 8719,

Tuesday, April 25, 2017 to Friday, May 5, 2017

News clips at a glance: April 15 – 21 

Total: ~ 60

Summary: A potpourri of topics attracted the media's attention, including atmospheric wave patterns, snowpack, weather models, and geoengineering. President Donald Trump signed bipartisan legislation to improve weather forecasting and research, a bill UCAR provided extensive information about to Congress.

Notable clips:

Legislation to Improve Weather Forecasting (UCAR):
Trump Signs Monumental Weather Bill Into Law to Help Forecasting, Researching Capabilities Across Weather Enterprise

Atmospheric Waves and Weather (Haiyan Teng, Grant Branstator, CGD):
California's Recent Weather Extremes: A Planetary-Scale Pattern of Atmospheric Waves May be Responsible for the State's Droughts and Floods
(Physics Today)

Climate Change and Snowmelt (Keith Musselman, RAL):
Scientists Look to Colorado to Improve Snowpack Science in a Warming Climate
(KMGH-TV, Channel 7 Denver, ABC affiliate)

Unifying Weather Forecasts and Climate Models (NCAR):
Take that Europe: Computer Modeler Aims to Give U.S. Lead in Weather Predictions
(Science Magazine, mentions NCAR's MPAS model)

Geoengineering (Kevin Trenberth, CGD):
Everything You Need to Know About Geoengineering
(Popular Science)

Heat's Impact Amid Changing Climate (Caspar Ammann, RAL):
Hundreds of Millions of Poor Menaced by 'Silent Killer': Heat
(Times of Oman/Thomson Reuters Foundation Ammann quoted, story also cites NCAR heat-impact estimates)

Climate and Rising Sea Levels (Claudia Tebaldi, CGD):
Climate Experts Release Latest Science on Sea Level Rise Projections

Design of Mesa Lab (NCAR):
A Portrait of I.M. Pei at (Nearly) 100
(New York magazine)

Social media highlights:

NCAR scientist Kevin Trenberth talked climate change on Facebook Live with Mike Nelson of KMGH-TV, Channel 7, Denver. The 20-minute interview has attracted nearly 14,000 views so far. Paul Douglas featured the Facebook Live interview in his weather blog in the Minneapolis Star-Tribune newspaper. 

Posted by Jeff Smith at ext. 2679,

Monday, April 24, 2017 to Friday, April 28, 2017

WHO:  All staff who travel internationally

WHAT:  Don’t travel with data that is not needed for your trip. Don’t take export controlled or other sensitive or controlled data on international travel if it is not required and authorized.

WHY:  U.S. customs officials are authorized to search or retain electronic devices, including digital cameras, cell phones, media players, disk drives, flash drives, tablet devices, and laptops, even without probable cause, to look for violation of export control regulations as well as other laws and regulations. To prepare for this possibility:

  • Don’t carry data you don’t want others to see: medical records, research data files that cannot be published, financial information, photos, etc.
  • Before you travel, back up any data that you don’t want to lose.
  • Consider taking a minimal device (clean laptop) equipped with only ordinary, recognizable software and minimal data so any search can be fast.

CONTACT:  For further guidance view or download “International Travel with Devices and Data”, contact, or your ECC (Export Compliance Coordinator).


Posted by Rebecca Swisher at ext. 8609,

Monday, April 24, 2017 to Friday, April 28, 2017

TIAA Individual Counseling Sessions for May 2017

Center Green 1 – Board Room 3150
Tuesday, May 2, 2017 from 8:00am - 4:30pm
Click here to schedule appointment with Julie Marshall 05/02 @ Univ Corp of Atmospheric Research

Foothills Lab 2 – Room 1002 
Thursday, May 18, 2017 from 9:00am - 4:00pm 
Click here to schedule appointment with Julie Marshall 05/18 @ Univ Corp of Atmospheric Research

Sign Up Today:
To schedule a counseling session: Click the above link 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.

Posted by Alyssa Fronk at ext. 8710,

Monday, April 24, 2017 to Thursday, May 18, 2017