2016 CIRA Seminars
Everybody has heard about climate change or global warming, and most people can link this change to the forcing elements of either carbon dioxide or greenhouse gases.
To understand Earth's climate and weather, you must understand clouds on scales ranging from the characteristic size of water molecules (a few Angstroms) to synoptic and global circulations (hundreds to thousands of kilometers). Large scale forcing drives processes at the scale of single water droplets and ice crystals while microscale processes feed back and affect the larger scales. In this talk I will span the first six orders of magnitude in that cascade.
2015 CIRA Seminars
Mercury (Hg) is a bioaccumulative neurotoxin that is emitted to the atmosphere from both natural and anthropogenic sources. Once in the atmosphere, chemistry and transport are fundamental in determining the introduction of Hg to terrestrial and aquatic ecosystems. While gaseous elemental mercury (Hg(0)) may remain in the atmosphere for months, chemical conversion to the more soluble oxidized form (Hg(II)) facilitates atmospheric deposition.
A critical aspect of human-induced climate change is how it will affect regional hydroclimate around the world. To leading order, the increased ability of the atmosphere to hold moisture as it warms, intensifies moisture transports, making sub-tropical dry regions drier and mid- to high latitude wet regions wetter. But regional changes in hydroclimate will also depend on how the atmospheric circulation responds to warming.
The Dominica Experiment (DOMEX) took place in the eastern Caribbean in the spring of 2011 with 21 research flights of the University of Wyoming King Air (UWKA) aircraft. The goal was an improved understanding of the physics of convective orographic precipitation in the tropics. The UWKA measured upstream and downstream airflow properties as well as the convective clouds and precipitation over the island of Dominica.
Stratospheric water vapor plays an important role in global climate, stratospheric chemistry and polar ozone destruction. Observations of water vapor in the stratosphere and most importantly in the tropical tropopause region are important tools to study trends and processes of stratospheric water vapor.
AMSR2 was launched in 2012 and provides the follow-on to AMSR-E launched in 2002. These two sensors form the basis of a climate data record of microwave-derived global sea surface temperature using the 6 GHz channel. For an accurate determination of variability over this time period, it is essential the sensors be intercalibrated. Due to the sensitivity of microwave brightness temperature to sea surface temperature, an accuracy of 0.5 deg C in sea surface temperature would require an intercalibration of 0.25 K. However, comparisons of AMSR2 to AMSR-E have found inconsistencies of more t
Increased recognition of the deep value of continuous recordings of Earth’s seismic wavefield has led to the discovery of a bestiary of new seismogenic processes as well as to the development of powerful new analysis methods. I will summarize representative historic and recent results from research arising from long-duration signals in areas of research that lie outside of the realm of traditional earthquake/monitoring-based seismology.
Permafrost is permanently frozen ground covering 24% of the northern hemisphere land surface and contains 1100 Gt of carbon in the form of frozen organic matter. Temperatures in the high northern latitudes are increasing twice as fast as the global average. As temperatures continue to increase and the permafrost begins to thaw, the organic matter will also thaw. Once thawed, the organic matter will decay, releasing carbon dioxide (CO2) and methane (CH4) into the atmosphere.
Anthropogenic influence on the composition of the atmosphere has caused harm to human health, shifts in climate, and perturbations to ecosystems. Assessing the relative influence of specific sources on various air quality and climate endpoints enables evaluation of tradeoffs between emissions reduction strategies and technological pathways to meeting environmental goals. The adjoint of a model calculates the relative importance of many model parameters on select endpoints with analytical accuracy.
The effects of the tropical Pacific El Nino-Southern Oscillation (ENSO) phenomenon are communicated to the rest of the globe via atmospheric teleconnections. Traditionally, ENSO teleconnections have been viewed as tropospheric phenomena, propagating to higher latitudes as Rossby waves. Recent studies, however, suggest an influence of the stratosphere on extratropical ENSO teleconnections. The primary modes of variability in the stratosphere are sudden stratospheric warmings (SSWs) and the tropical quasi-biennial oscillation (QBO).
Recent field observations from the Profiling of Winter Storms (PLOWS) campaign suggest that cloud-top precipitation generating cells (GCs) are ubiquitous in the warm-frontal and comma-head regions of midlatitude winter cyclones. The presence of fall streaks emanating from the GCs, and their persistence either to the surface or until merging into precipitation bands suggests that GCs are a critical component of the precipitation process in these cyclones. Accordingly, an understanding of the dynamics and thermodynamics that control their development and maintenance is needed.
Hosted by the FORT Collins Atmospheric ScientisTs (FORTCAST) AMS local chapter and the American Association for Aerosol Research (AAAR) CSU chapter.
How do people think about environmental problems like climate change, and why do some people feel concerned or take action? Despite large consensus among the scientific community, many individuals deny that climate change is happening or that it is a serious issue. Although there are many possible reasons why people disengage from the issue, a common link is that they do not feel personally and psychologically connected to the impacts of climate change.
Natural gas, crude oil, and natural gas liquids are major fuel sources in the US, and extraction of these resources has been rising substantially since the mid 2000’s. This activity is associated with a range of possible environmental issues, including air quality impacts on local, regional, and global scales. Field observations of air chemistry are crucial in order to understand the extent and causes of these issues, and to develop mitigation strategies.
Next generation air measurements (NGAM) is an EPA term for the rapidly advancing field of air pollutant sensor technologies, data integration concepts, and associated geospatial modeling strategies. Ranging from personal sensors to satellite remote sensing, future NGAM systems promise revolutionary new capability for air quality and exposure science. NGAM tools may be particularly useful in understanding emissions from fugitive and area sources of air pollution and greenhouses gases.
The natural causes of global, regional, and local climate variations and changes are important, but the human influences are also significant. However, the Intergovernmental Panel on Climate Change ( IPCC) and other climate assessments have too narrowly focused on CO2 and a few other greenhouse gases in altering local, regional and global climate and their effects on multi-decadal predictability. Also, climate is much more than just global warming.
In the central and eastern U.S., as well as other continental locations at midlatitudes around the world, warm-season heavy precipitation is most frequent at night.
What: 5–10 min intros by individual CIRA members
Who: Don Hillger, John Knaff, Dan Lindsey, Steve Miller, Matt Rogers, Jenny Hand, Karina Apodaca
Why: provide overview of some current research within CIRA
Why2 : pizza and socializing after (in Weather Lab)
Light snowfall often falls over mountains long after deep frontal disturbances have passed. We use high-resolution profiling radar observations over Colorado and Wyoming, as well as numerical simulations, to explore mechanisms of such persistent precipitation from rather shallow clouds. These clouds are often convective, in which case they tend to deposit relatively more snow on the lee side of mountains, compared to stratiform clouds. Strong winds are often present and the associated boundary-layer turbulence itself may enhance snowfall in mixedphase clouds.
Soot, the by-product of combustion, that smoky, black crap from chimneys, power plants and the inside of the tail pipe of my roadster, what scientist would ever bother to study soot? As a “particle physicist”, that’s what I do, and I find that soot has mysteries and beauties that can entertain any curiosity.
Thunderstorms are interesting from an atmospheric chemistry perspective because their convective outflow regions produce ozone in the upper troposphere, where ozone is radiatively active as a greenhouse gas. The ozone production comes about because the convective outflow contains an abundance of ozone precursors: hydrogen oxides (HOx) radicals and their precursors, as well as nitrogen oxides (NOx). Boundary layer air, rich in hydrocarbons, other HOx precursors, and NOx, is rapidly transported from the surface to the upper troposphere by deep convection.
Thunderstorms and lightning pose a safety risk to personnel working outdoors. Airport and airline operators, therefore, employ safety procedures that include observations and warnings of the onset and duration of lightning hazards. Ramp closures are needed to ensure the safety of outdoor personnel servicing gate-side aircraft. Yet halting outdoor work delays air traffic and can cause ripple effects beyond the impacted airport.
In the 1950s, pioneering scientists used the new technology of vertically pointing radar to discover that the warm frontal and occluded sectors of winter cyclones were commonly topped by convective “generating cells” that produced snow streamers that merged and were organized by shear to produce linear bands.