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<p class="HTMLBody" align="center" style="text-align:center;line-height:115%"><b><u><span style="font-size:26.0pt;line-height:115%;font-family:"Monotype Corsiva"">Meteorology Seminar<o:p></o:p></span></u></b></p>
<p class="HTMLBody" align="center" style="text-align:center;line-height:115%"><b><span style="font-size:28.0pt;line-height:115%;font-family:"Monotype Corsiva"">Jason Ducker</span></b><span style="font-size:28.0pt;line-height:115%;font-family:"Monotype Corsiva""><o:p></o:p></span></p>
<p class="HTMLBody" align="center" style="text-align:center"><span style="font-size:28.0pt;font-family:"Monotype Corsiva"">PhD Meteorology Candidate<o:p></o:p></span></p>
<p class="HTMLBody"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="doublespacedcaps" align="left" style="text-align:left;line-height:normal">
<b><u><span style="font-size:14.0pt">Title</span></u>:</b> <b><span style="font-family:"Calibri",sans-serif;color:black">Developing new datasets to </span></b><b><span style="font-size:11.5pt;font-family:"Calibri",sans-serif;color:black">evaluate</span></b><b><span style="font-family:"Calibri",sans-serif;color:black"> tropospheric
photochemistry and the effects of ozone uptake in the biosphere</span></b><span style="font-size:14.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><u><span style="font-size:14.0pt">Major Professor</span></u></b><b><span style="font-size:14.0pt">: Dr. Christopher Holmes</span></b><b><u><span style="font-size:14.0pt;font-family:"Times",serif"><o:p></o:p></span></u></b></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><u><span style="font-size:14.0pt">Date</span></u></b><b><span style="font-size:14.0pt">:</span></b><span style="font-size:14.0pt"> November 4, 2019
<b><u>Time</u>: 1:00 PM</b></span><span style="font-size:14.0pt;font-family:"Times New Roman",serif"><o:p></o:p></span></p>
<p class="HTMLBody"><b><o:p> </o:p></b></p>
<p class="HTMLBody"><b><u><span style="font-size:14.0pt">Location</span></u></b><b><span style="font-size:14.0pt">:
</span></b><span style="font-size:14.0pt">Werner A. Baum Seminar Room (353 Love Building)<b><o:p></o:p></b></span></p>
<p class="MsoNormal"><b>(Please join us for refreshments served outside room 353 Love @ 12:30 PM)</b><b><span style="font-size:12.0pt"><o:p></o:p></span></b></p>
<p class="MsoNormal" align="center" style="text-align:center"><b>ABSTRACT<o:p></o:p></b></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-family:"Times New Roman",serif">In the presence of water vapor, photolysis of tropospheric ozone (O<sub>3</sub>) produces the hydroxyl radical (OH), which is a strong oxidant that directly and
indirectly controls a host of greenhouse gases and air pollutants. When tropospheric O<sub>3</sub> reaches the surface, its oxidative effects perturb plant transpiration and photosynthesis. Although these effects have been included in climate and air quality
models, there are limited observational datasets to constrain key aspects of atmospheric photochemistry and O<sub>3</sub> deposition on regional to global scales. This dissertation develops and uses two new datasets to better understand the ozone photochemistry
and impacts. <o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-family:"Times New Roman",serif">Photolysis, the breaking of chemical bonds by sunlight, is the engine for reactive</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">atmospheric chemistry. It controls production of atmopsheric oxidants,</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">especially O</span><sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">3</span></sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">and OH, which then influence the lifetimes of other</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">air pollutants and climate forcing agents. Global chemistry and climate models</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">differ in their estimates of these photolysis rates and there hasnt been</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">datasets capable of discriminating amongst different models. Here, we integrate</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">satellite-retrivals of clouds and aerosols into a photolysis code and produce a</span><span lang="MR" style="font-family:"Adobe Devanagari",serif"> 3-</span><span style="font-family:"Times New Roman",serif">D
global photolysis dataset called Sat-J. We show that Sat-J is tightly</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">correlated with in-situ measurements of photolysis rates from airborne</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">chemistry campaigns, with errors (4-</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">20%)
</span><span style="font-family:"Times New Roman",serif">mainly attributed to</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">differences in cloud sampling and surface albedo characteristics.</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">By comparing regional, not necessarily collocated, averages of aircraft data, SatJ, and a chemistry model (GEOS-Chem); we demonstrate that SatJ provides a representative climatology of photolysis rates
across the globe and can serve as a benchmark for photochemistry models.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-family:"Times New Roman",serif">Using surface micrometeorological fluxes and surface O<sub>3</sub> monitoring networks, we also develop and evaluate a method to estimate O<sub>3</sub> deposition
and stomatal O<sub>3</sub> uptake across networks of eddy covariance flux tower sites where O<sub>3</sub> concentrations and O<sub>3</sub> fluxes have not been measured. This method, called SynFlux, reproduces the variability in daily stomatal O<sub>3</sub>
uptake at sites with O<sub>3</sub> flux measurements, with a modest bias (21% or less) attributed to gridded O<sub>3</sub> concentrations. Across</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">SynFlux sites, we highlight environmental factors controlling spatial patterns</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">in O</span><sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">3</span></sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">deposition and showed that previous O</span><sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">3</span></sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">concentration-based metrics for plant damages did not correlate with SynFlux O</span><sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">3</span></sub><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">uptake, which is a better predictor for plant damage than ambient concentration</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif">in air.</span><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span><span style="font-family:"Times New Roman",serif"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-family:"Times New Roman",serif">SynFlux</span><b><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span></b><span style="font-family:"Times New Roman",serif">has</span><b><span lang="MR" style="font-family:"Adobe Devanagari",serif">
</span></b><span style="font-family:"Times New Roman",serif">dramatically expanded the available data on surface O<sub>3</sub> deposition, which can now be used for performing ecosystem impact studies across a species and climates in the US and Europe. Past
controlled experiments involving single plant species have shown that O<sub>3</sub> uptake can degrade water-use efficiency (WUE), which is the ratio of carbon uptake in photosynthesis (GPP) to water loss in plant transpiration (T). Using SynFlux sites, we
can quantify this effect for whole ecosystems under natural environmental variability, which has not been previously studied. Across 74 SynFlux sites, we find a significant negative relationship (–0.02% per
</span><!--[if gte msEquation 12]><m:oMath><i><span style='font-family:"Cambria Math",serif'><m:r>μ</m:r></span></i></m:oMath><![endif]--><![if !msEquation]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;position:relative;top:2.5pt;mso-text-raise:-2.5pt;mso-fareast-language:EN-US"><img width="8" height="17" style="width:.0833in;height:.177in" id="_x0000_i1025" src="cid:image001.png@01D58D77.CFC4BF20"></span><![endif]><span style="font-family:"Times New Roman",serif">mol
m<sup>-2</sup> d<sup>-1</sup>) between daily cumulative O<sub>3</sub> uptake (CUO) and WUE anomalies, with the largest impacts occurring at forest sites. Past controlled studies of selected individual species also observed a similar O<sub>3</sub> reduction
of WUE over the growing season, indicating a consistent response to O<sub>3</sub> across multiple species with an ecosystem. When we analyze the relationships between daily CUO and GPP or T anomalies, we also find that CUO degrades GPP and increases T over
the growing season. We postulate that O<sub>3</sub> degrades WUE through O<sub>3</sub> non-stomatal biochemical factors, which result in a reduction of GPP or an increase in T. Our SynFlux results here provide climate models the ability to incorporate O<sub>3</sub>-dose
response relationships between O<sub>3</sub> uptake and ecosystem carbon and water vapor fluxes across ecosystems that have not previously been studied.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Shel McGuire<o:p></o:p></p>
<p class="MsoNormal">Florida State University<o:p></o:p></p>
<p class="MsoNormal">Academic Program Specialist<o:p></o:p></p>
<p class="MsoNormal">Department of Earth, Ocean, & Atmospheric Science<o:p></o:p></p>
<p class="MsoNormal">1017 Academic Way, 410 Love Building (Meteorology)<o:p></o:p></p>
<p class="MsoNormal">Tallahassee, FL 32306<o:p></o:p></p>
<p class="MsoNormal">850-644-8582<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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