Increasing synoptic scale variability in atmospheric CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; at Hateruma Island associated with increasing East-Asian emissions

Y Tohjima,H Mukai,P K Patra,S Hashimoto

doi:10.5194/acp-10-453-2010

Abstract

Abstract. In-situ observations of atmospheric CO2 and CH4 at Hateruma Island (24.05° N, 123.80° E, 47 m a.s.l), Japan shows large synoptic scale variations during a 6-month period from November to April, when the sampled air is predominantly of continental origin due to the Asian winter monsoon. Synoptic scale variations are extracted from the daily averaged values for the years between 1996 and 2007, along with the annual standard deviations (σCO2 and σCH4 for CO2 and CH4, respectively) for the relevant 6-month period. During this 6-month period the absolute mixing ratios of CO2 and CH4 at Hateruma are also elevated compared to those at two sites in the central North Pacific Ocean. The temporal change in σCO2 shows a systematic increase over the 12-year period, with elevated excursions in 1998 and 2003; there is no clear increase in σCH4. We also find that the σCO2/σCH4 ratio increases gradually from 1996 to 2002 and rapidly after 2002 without any extreme deviations that characterised σCO2. The σCO2/σCH4 ratio correlates closely with the recent rapid increase in fossil carbon emissions from China, as indicated in the Carbon Dioxide Information Analysis Center (CDIAC) database. This methodology can be applied to multiple chemical tracers of sufficient lifetime, for tracking overall changes in regional emissions.

Highlights

The increase in carbon dioxide (CO2) emissions from fossil fuel consumption, cement manufacturing and decomposition of biomass and soil organic matter associated with land-use changes has contributed to the observed rise in atmospheric CO2 since the industrial revolution (Marland et al, 2007; Houghton, 2003)
The levels of CO2 and CH4 mixing ratios at Hateruma Island (HAT) are greater than those at Mauna Loa (MLO) during the period of our analysis (November– April). This gradient in mixing ratio between HAT and MLO is caused by the high continental emissions and the prevailing northwesterly winds across East Asia, compared to the tropics of the North Pacific Ocean
El Nino events alter wind and radiation (outgoing long-wave readiation (OLR), for example) patterns (Trenberth, 1997), causing anomalous transport and anomalous enhancement of CO2 and CH4 mixing ratios in the source region that could explain the enhanced variability in CO2 and CH4 at HAT observed in 1998 and 2003

Summary

Introduction

The increase in carbon dioxide (CO2) emissions from fossil fuel consumption, cement manufacturing and decomposition of biomass and soil organic matter associated with land-use changes has contributed to the observed rise in atmospheric CO2 since the industrial revolution (Marland et al, 2007; Houghton, 2003). Despite international discussions to reduce greenhouse gas emissions, global CO2 emissions from fossil fuel consumption and cement manufacturing derived from the CDIAC database (Marland et al, 2007) show an unprecedented accelerated growth during the period 2002–2006. This rapid emission growth has been attributed to the accelerating emissions from the developing countries, especially China (Raupach et al, 2007; Gregg et al, 2008). The ratio of CO2 and CH4 SSVs is used to construct a conservative tracer for tracking emission changes over the source regions

Data and methods

Results

70 Korea x 5

Discussion