Sunday, September 30, 2007
Sunday, September 23, 2007
UN/Austria/ESA Symposium on “Space Tools and Solutions for Monitoring the Atmosphere in Support of Sustainable Development”: My Experience
The symposium was a good combination of invited talks, participant presentations and hands-on training workshop. Invited talks covered several important areas including overview of earth observations, satellite applications for atmospheric monitoring, global and regional initiatives, air quality (ozone and particulate matter), climate change and weather.
Hands-on training on satellite tools for air quality monitoring was informative and every single participant experienced handing of satellite data and I am very sure they enjoyed it immensely. The training used four different case studies of heavy aerosol events when particulate matter air quality on the surface was very poor in the region. Case studies covered two recent biomass burning events, one dust storm and one with a mixture of urban pollution and smoke from fires. The participants from the symposium were divided into groups of 3-4 people and each group was provided with a laptop computer. After initial introduction on monitoring air pollution from satellite observations, each group analyzed one case study. Air quality analysis includes identifying different features such as aerosols, clouds, water, land etc in the satellite images, quantifying aerosol loading using aerosol optical thickness, observations on local meteorological conditions and back trajectory analysis to track air mass in and out from the regions of interest. One of the most important parts of this exercise was to obtain different data sets and images from freely available online resources. Every group liked this part and learnt simple solutions to address specific air quality events using satellite imagery. Finally, participants used the tools that they learnt in the workshop to identify air quality color codes in their city or region of interest.
I really enjoyed the entire training session and discussed many different issued related to air quality in different parts of the world. The last day of the symposium was used to identify different problem associated with air quality research and monitoring of air pollution in the participant's country or region. There were several recommendations made by two working groups on air quality monitoring network, data sharing, and policy related issues to the United Nations.
Evening receptions and tours within Graz city were wonderful and served as a time of relaxation after the busy working days for all participants.
Finally, I would like to congratulate and thank all the people who were directly or indirectly involved in organizing such a great successful symposium.
More details about the symposium can be found out on following web link
http://www.unoosa.org/oosa/SAP/act2007/graz/index.html
(Pawan Gupta)
The University of Alabama in Huntsville
Huntsville, AL, USA
P.S: The participants were eager to know the various resources that are available to them on the internet for various data sources. Here are a list if some websites that will be useful.
GIOVANNI: MODIS, MISR, TOMS, OMI aerosol daily and monthly data can be obtained and visualize online using various options available.
MODIS Atmosphere: Details description on MODIS atmospheric products such as aerosols, clouds, water vapor and atmospheric profiles. This is very good site to learn about data, algorithms and updates on publications.
MODIS Rapid Response System: True-color, photo-like imagery and false-color imagery are available within a few hours of being collected by MODIS.
NASA Visible Earth: This is good catalog for different Earth’s images from NASA.
International Air Quality: This site is hosted on USEPA webpage, which provides link to available online resources for international air quality monitoring.
IDEA: This site provides surface and satellite assessment of particulate matter air quality over United States.
NRL Aerosol Page: This site provides model forecasts of various aerosol fields for global regions. This site also maintain very good list of links related to atmospheric aerosol research.
Posted by Pawan Gupta at 11:15 PM 0 comments
Labels: conference, pawan
Monday, September 17, 2007
History of Aerosol Science
The first time my interest in aerosol science picked up was when I learnt about nuclear winter -- a phenomena which refers to possible climatic impact of all-out nuclear war. What really fascinated me was the idea that if one wants to control climate or weather in predictive manner, aerosols are going to be the best tool; for a reason that they have relatively short life-time giving control over their introduction and removal in the atmosphere. Well! this is not the subject of today's post. Thinking of my own interests in this field led me to think about history of aerosol science. Couple of years before I read Spencer Weart's "The Discovery of Global Warming". I am fascinated by its content and writing style. Experience was not less than reading suspense thriller. Later on, I come across a comment that book is weighted toward contributions of American scientists than European scientists. I do not know the truth as my knowledge in the history of climate science is limited. But if asked Weart's book is my first recommendation.
Thursday, September 6, 2007
Treating Dust As A Spherical Particle: Good/Bad Assumption?
Figure above shows the relative difference of calculated settling velocity between ellipsoidal and spherical particles {Δu∞ = 100% × [u∞ (λ) − u∞ (λ = 1)]/u∞ (λ = 1)}. For example, the settling velocity of particles of 2 μm diameter increases respectively around 50%, 100%, and 165% for aspect ratios of 2, 4, and 10. The relative difference decreases with increasing particle size. For particles of 10 μm, the settling velocity increase for ellipsoids is around 30–40%, with little difference shown for aspect ratios of 1–10. On the other hand, a 40% decrease of settling velocity for ellipsoids is apparent at around 40–50 μm for the aspect ratio of 10.
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