<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none"><!--P{margin-top:0;margin-bottom:0;} p
{margin-top:0;
margin-bottom:0}--></style>
</head>
<body dir="ltr" style="font-size:12pt;color:#000000;background-color:#FFFFFF;font-family:Calibri,Arial,Helvetica,sans-serif;">
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-GB">Hi all, </span><span style="font-size:12.0pt"></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; text-align:right; line-height:normal" align="right">
<span style="font-size:12.0pt"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-GB">Next week it’s time for a MISU theme seminar “Earth in Space”.
<br>
</span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-GB">William Ball, researcher at ETH </span>
<span style="font-size:12.0pt" lang="EN-US">Zürich,</span><span style="font-size:12.0pt" lang="EN-GB"> will talk about the evidence for a continued ozone layer reduction.</span><span style="font-size:12.0pt" lang="EN-US"></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"> <img name="null" title="seminar8.jpg" class="" style="display:inline; margin:5px; width:157px" src="https://ebox.su.se/owa/service.svc/s/GetFileAttachment?id=AAMkAGJhYmMyZDU2LTVhNGItNGUyYy04Yzc2LWI4YjBlMmU0MzA2YQBGAAAAAAD%2BgwkLLqRSR5Ocj74yqr3gBwCBEoH%2F179CTIKfn9NqpzdkAAAAK8TkAAC%2BmzFX4U17Q48pX%2Borw05sAAKWuCVOAAABEgAQAPwIquB6dgpGvuVvBVsl2mo%3D&X-OWA-CANARY=8ANKHKOxKkGrtLkMTlX0IUiu5_6FsdUIIGqYjZHEBSzUBVxFQMNoj_f2g7wntdAZTxcHDGtRm6M."></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-GB"> </span><span style="font-size:12.0pt" lang="EN-US"></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<strong><span style="font-size:12.0pt" lang="EN-US">Name</span></strong><span style="font-size:12.0pt" lang="EN-US"><br>
<a href="http://www.iac.ethz.ch/people-iac/person-detail.html?persid=221373" target="_blank"><span style="color:blue">William Ball</span></a><br>
Institute for Atmospheric and Climate Science, ETH Zürich, Switzerland<br>
<br>
<strong>Title</strong><br>
Evidence for continued ozone layer reduction<br>
<br>
<strong>Time and place</strong><br>
Tuesday May 8th, 11.15<br>
Rossbysalen C609, Arrhenius Laboratory, 6th floor<br>
<br>
<strong>Abstract</strong><br>
Stratospheric ozone protects life from harmful ultraviolet radiation. The Montreal Protocol, enacted to prevent ozone depletion from human activity, halted declines in column-integrated ozone in the 1990s; the upper stratosphere is recovering, but lower stratospheric
trends are unknown. </span></p>
<p class="MsoNormal" style="line-height:normal"><span style="font-size:12.0pt" lang="EN-US">To accurately estimate decadal trends in stratospheric ozone requires combining observations from multiple instruments. However, trends between composites disagree due
to data-artefacts that remain after merging data together. We developed a new methodology to account for the artefacts using only the data itself in addition to prior knowledge about ozone variability and known problems during instrument operation. Furthermore,
we use dynamical linear modelling (DLM), a Bayesian multiple linear regression, to estimate robust trends. </span></p>
<p class="MsoNormal" style="line-height:normal"><span style="font-size:12.0pt" lang="EN-US">As a result of building confidence in the data, we find clear evidence that lower stratospheric ozone continues to decline, preventing total ozone recovery. This result
contradicts expectations and, with no clear understanding of why this trend has emerged, implies that the problem of ozone depletion is not yet fully resolved. The decline may have an impact future estimates of ozone layer recovery and future surface levels
of ultraviolet radiation.</span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><br>
<strong>Welcome!<br>
</strong></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><strong><br>
</strong></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><strong><br>
</strong></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><strong><br>
</strong></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US">Kind regards,<br>
</span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US">Lena Frey<br>
</span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><strong><br>
</strong></span></p>
<p class="MsoNormal" style="margin-bottom:0cm; margin-bottom:.0001pt; line-height:normal">
<span style="font-size:12.0pt" lang="EN-US"><strong><br>
</strong></span><span style="font-size:12.0pt" lang="EN-US"></span><span style="font-size:12.0pt"></span></p>
<p><br>
</p>
<div id="Signature">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font face="Arial"><font size="2"><font color="808080">Lena Frey, PhD student
<br>
Department of Meteorology<br>
Stockholm University, Sweden<br>
Phone: +46-(0)8-162<font color="808080">40</font>7</font><br>
</font><br>
</font></div>
</div>
</div>
</div>
</body>
</html>