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GCOE-ARS特別セミナー
GCOE-ARS Special Seminar

 

We will hold the Special GCOE-ARS Seminar with the following contents. We welcome all interested Staffs and Graduate School Students (especially those who have registered to GCOE-ARS course).

 

日時/Date: 2012年5月9日(Wed)13:00-14:30
April 13, 2012 [Fri]
場所/Place: 京都大学 吉田キャンパス(北部構内)
理学部1号館5階 563号室
Kyoto University, Yoshida Campus, Room# 563, Faculty of Science Bldg. #1

 

演題/Title:

Applications of Lagrangian modeling to atmospheric composition problems

 

講師/Name of the speaker

Dr. Ignacio PISSO (Research Institute for Global Change/JAMSTEC)

 

要旨/Summary:

The calculation of Lagrangian trajectories advected by meteorological winds provides a modeling tool suited to assess both backward and forward modeling problems of atmospheric composition.

 

As an example of forward modeling involving large ranges of spatio-temporal scales, we present a trajectory-based estimates of Ozone Depletion Potentials (ODPs) for very short-lived halogenated source gases as a function of surface emission location. The ODPs are determined by the fraction of source gas and its degradation products which reach the stratosphere, depending primarily on tropospheric transport and chemistry, and the effect of the resulting reactive halogen in the stratosphere, which is determined by stratospheric transport and chemistry, in particular by stratospheric residence time. Reflecting the different timescales and physico-chemical processes in the troposphere and stratosphere, the estimates are based on calculation of separate ensembles of trajectories for the troposphere and stratosphere. A methodology is described by which information from the two ensembles can be combined to give the ODPs. The estimated ODPs show strong geographical and seasonal variation, particularly within the tropics. These first estimates show larger ODPs for certain emission regions, particularly South Asia in NH Summer, than have typically been reported by previous studies for emissions distributed over land in within broad latitudinal bands.

 

Lagrangian methodologies allow also to exploit high resolution in situ measurements. As an example of backward trajectory modeling and in order to constrain regional emissions of carbon dioxide (CO2), we use a Lagrangian methodology based on diffusive backward trajectory tracer reconstructions. We use aircraft, tall tower and ground sites for CO2 data collected nearby the CO2 hot spot of the Tokyo Bay Area during the CONTRAIL campaign, from the MRI/JMA Tsukuba tall tower and from the World Data Centre for Greenhouse Gases (WDCGG). We calculated Bayesian inversions based on EDGAR 4 and CDIAC a priori fluxes. Estimated fluxes for the Tokyo Bay Area for the analyzed period between 2005 and 2009 range between 4.80×10-7 and 3.45×10-6kgCO2m2s-1 with significant time variations. Significant differences in retrieved fluxes of up to 21 % were found when CONTRAIL measurements were added to the dataset. No significant trend was found in the time series of spatially averaged retrieved fluxes.

 

ポスター(PDF)

問い合わせ先/Contact: GCOE-ARS事務局 secretariat@ars.gcoe.kyoto‐u.ac.jp

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