Major Events

No meetings, workshops, or other special events are currently announced.

+ Past Meetings & Workshops

Other Upcoming Events

Following are upcoming seminars, workshops and other events of interest to GISS staff and our research partners. Please note that due to security regulations, these presentations are not open to the general public.

Friday, Aug. 5, 2016
9:00 a.m. to 5:00 p.m.
CCRI PowerPoint Research Symposium
Contact: Matt Pearce
Wednesday, Aug. 17, 2016
11:00 a.m. to 12:30 p.m.
Special Seminar
Topic: Cloud Microphysical Responses to Electric Charges Due to Atmospheric Ionization: Observations, Simulations, and Parameterization
Speaker: Brian Tinsley (University of Texas)
Abstract: Read More
Contact: Ann Fridlind

Special Seminar
Speaker: Brian Tinsley (University of Texas)
Title: Cloud Microphysical Responses to Electric Charges Due to Atmospheric Ionization: Observations, Simulations, and Parameterization

Abstract: The discrepancy between observed rates of production of ice in mixed phase clouds and the rates calculated from observed concentrations of ice-forming nuclei concentrations has been a puzzle since Hobbs and Rangno pointed it out in 1985. Contact ice nucleation rates from standard microphysical schemes are not great enough, nor are rates of collection of ice-forming-nuclei in updrafts, since the net phoretic forces are repulsive for condensing droplets. Atmospheric ionization is ubiquitous, forming bipolar (i.e., of both signs) charged nuclei within clouds, and largely unipolar charged nuclei at cloud boundaries, due to the flow of current in the global electric circuit. Effects of charges on scavenging of nuclei were explored by Pruppacher and students, and now with much faster computers we have constructed a trajectory model of scavenging, with Monte-Carlo simulation of diffusion. This simulates the effect of charge and phoretic forces and weight and flow fields on scavenging for a wide range of particle and droplet sizes and charges and ambient relative humidities. For larger nuclei, electro-scavenging increases the collection rates irrespective of charge sign, and in updrafts particles can be collected below the freezing level as a source for immersion nuclei when droplets rise above it, as well as being collected for contact nucleation there. For smaller nuclei electro-anti-scavenging in unipolar environments decreases the rates of collection, affecting CCN concentrations and size distributions. We have parameterized the results, for incorporation in cloud models, to test whether the effects of charge are large enough to explain the long-standing discrepancy.

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Thursday, Sep. 15, 2016
11:00 a.m. to 12:30 p.m.
Climate Center Lecture
Speaker: Stephen Meyers (University of Wisconsin)
Abstract: Read More
Contact: Allegra N. LeGrande

Climate Center Lecture
Speaker: Stephen Meyers (University of Wisconsin)

Abstract: Climate Center (LDEO/GISS) Lecture

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Friday, Oct. 7, 2016
11:00 a.m. to 12:30 p.m.
Friday Seminar
Speaker: Michael Previdi (LDEO)
Abstract: Read More
Contact: Darren Engwirda

Friday Seminar
Speaker: Michael Previdi (LDEO)
Title: TBA

Abstract: TBA

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This event listing was last updated 2016-07-20.

Seminars & Colloquia

Most seminars at NASA GISS are held during the academic year, September through May.

Formal seminar presentations by visiting scientists are held many Fridays at 11:00 a.m.

Informal lunchtime presentations by GISS staff take place on Wednesdays at 1:00 p.m. about twice per month.

Other special seminars occur from time to time as visitors' schedules permit.

Security Note

Regulations require that visitors arrange in advance for a building pass. All persons attending a NASA GISS seminar or colloquium should contact the event host at least two business days in advance of the event for assistance. Please include your affiliation in your e-mail.

Special arrangements must be made for persons who are not U.S. citizens or U.S. permanent residents. Such persons should contact the event host at least seven business days in advance of visiting GISS.

Effective July 21, 2014, implementation of Phase II of the Real-ID Act (2005) restricts the use of state ID from non-compliant states (including New York) as an acceptable form of identification for federal facilities such as NASA GISS. If you have scheduled a visit to GISS and only have a standard driver's license from a non-compliant state, please be sure to bring a second form of ID (passport, military ID, etc.).