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The Tohoku earthquake of 11 March 2011, with moment magnitude Mw= 9.0, and subsequent tsunami caused catastrophic structural damage in east Japan. Using high‐frequency atmospheric monitoring data, we show that emissions of halocarbons, potent greenhouse gases and stratospheric ozone‐depleting substances, dramatically increased shortly after the earthquake and that annual emissions were significantly higher in 2011 than in other years. We estimate that the sum of earthquake‐related emissions of the six studied halocarbon species (CFC‐11, HCFC‐22, HCFC‐141b, HFC‐134a, HFC‐32, and SF6) was 6.6 (5.2–8.0) Gg, which is equivalent to ozone depletion potential‐weighted emissions of 1.3 (1.1–1.6) Gg with a global warming potential equivalent to 19.2 (15.8–22.5) Tg of carbon dioxide. These extraordinary halocarbon emissions are likely due to destruction of building components containing halocarbons, such as air conditioners, foam insulation, and electrical equipment. High‐frequency measurements of halocarbon have been made in JapanThese data combined with model suggest large Japanese emissions in 2011The extraordinary halocarbon emissions are likely due to the Tohoku earthquake

We elucidated multiyear variations of sea surface dissolved inorganic carbon (DIC) concentrations in the North Pacific from 2002 to 2008 by using monthly DIC maps derived from partial pressure CO2observations. The Pacific Decadal Oscillation (PDO) was related to an east‐west seesaw pattern in the North Pacific DIC anomaly field. In the western North Pacific, DIC concentrations were relatively high from mid‐2002 to mid‐2005 and low after late 2007 compared with climatological values, and in the eastern North Pacific the opposite change was observed. Changes of the forcing factors associated with the PDO could explain the DIC east‐west seesaw pattern: horizontal advection, freshwater fluxes and vertical mixing in most regions, CO2fluxes south of 40°N, and biological production in the subarctic. PDO induces DIC east‐west seesaw pattern in the North PacificChanges of environmental variables can explain the DIC pattern

We produced 84 monthly maps of sea surface dissolved inorganic carbon (DIC) concentration for the North Pacific from 2002 to 2008. The estimated DIC concentration agrees well with DIC concentration observed from research vessels at fixed time series stations (root‐mean‐square error of 10.2 μmol kg−1). The spatial distribution of 7 year annual mean DIC concentration corresponds to the sea surface salinity distribution and ocean circulation. We explored DIC seasonal variation by categorizing the North Pacific into 10 areal clusters. DIC decrease from March to July was captured: more than 120 μmol kg−1in the northwest, but less than 40 μmol kg−1in the subtropics. After subtracting the effects of air‐sea CO2flux and salinity change, the residual DIC decrease from March to July can be considered as net community production (NCP): more than 14 mmolC m−2d−1in the boundary region between the subtropics and the subarctic extending from east coast of Japan to the date line, more than 8 mmolC m−2d−1in the coastal region of the subarctic, and 4–8 mmolC m−2d−1in the offshore region of the subarctic. The NCP corresponds well to 20–30% of the satellite‐derived net primary production. Monthly maps of sea surface DIC are produced in the North PacificAnnual mean DIC distribution corresponds to salinity and ocean circulationDIC decrease from winter to summer indicates net community production

Environmental contextAtmospheric carbon monoxide greatly affects the abundance of environmentally important gases, including methane, hydrochlorofluorocarbons and tropospheric ozone. We present evidence for episodes of CO pollution over the tropical Pacific Ocean resulting from intensive biomass burning in South-east Asia and Northern Australia during the 2006 El Niño year. We discuss the locations of the CO emissions and their long-range transport.AbstractBiomass burning is often associated with climate oscillations. For example, biomass burning in South-east Asia is strongly linked to El Niño–southern oscillation activity. During October and November of the 2006 El Niño year, a substantial increase in CO mixing ratios was detected over the Western tropical Pacific Ocean by shipboard observations routinely operated between Japan and Australia and New Zealand. Combining in-situ measurements, satellite observations, and an air trajectory model simulation, two high CO episodes were identified originating from biomass burning in Borneo, Sumatra, New Guinea, and Northern Australia. Between 15°N and the Equator, marked CO enhancements were encountered associated with a significant correlation between CO and CO2and between CO and O3. The ΔCO/ΔCO2ratio observed in the fire plume was considerably high (171ppbvppmv-1), suggesting substantial contributions from peat soil burning in Indonesia. In contrast, the ΔO3/ΔCO ratio was only 0.05ppbvppbv-1, indicating that net photochemical production of O3in the plume was negligible during long-range transport in the lower troposphere over the Western tropical North Pacific.

The observation network of atmospheric radon-222 (222Rn) concentration established in East Asia region is introduced, and the characteristics of the observations at two continental sites Beijing and Seoul and three remote sites Cape Ochiishi, Hachijo Is. and Hateruma Is. are discussed in this paper. Higher levels of 222Rn concentrations with typical diurnal variation with early morning maxima were observed on the continent, and lower levels with no diurnal variation at remote islands. Seasonal variations with summer minima and winter maxima were commonly obtained at all five observatories, and they suggested contribution of 222Rn originated from the continent to atmospheric 222Rn over the remote islands isolated in the ocean. A backward trajectory analysis showed clear relationship between variation in wind field and in 222Rn concentration at Hachijo Is., and proved availability of the observation for analysis of atmospheric transport in East Asia.

A three-dimensional Eulerian numerical model for 222Rn and its decay products coupled with a mesoscale meteorological model has been developed and applied to the reproduction of the daily and monthly variations of 222Rn concentration, the monthly variation of 210Pb deposition in Japan and the temporal variation of gamma dose rate after the cold front passage in the coastal area of the Japan Sea for the verification of model capability. The results are as follows: (1) The model reproduced the monthly variation of surface 222Rn concentration in remote islands, but underestimated inland concentration due to a coarse vertical resolution near the surface of the model. (2) The model reproduced the seasonal variation of the observed and the long-term yearly averaged 210Pb depositions as long as precipitations are predicted precisely. (3) The model reproduced the rise of gamma dose rate in precipitation accompanied by the cold front passage. In particular, 222Rn decay products in melted snow and graupel contributed the rise of gamma dose rate.

In-depth knowledge of global and regional carbon budget is required for effective policymaking to mitigate the global climate change. However, Asian carbon budget shows large uncertainty due to both lack of sufficient observations and detailed understanding of the existing CO2observations. A regional air quality model (WRF–CO2) is set up for simulating atmospheric CO2variations over the greater Asia region (68–124°E, 2°S–45°N) for the period 2010–2012. The WRF–CO2simulations are compared with observations from nine sites and a global Atmospheric Chemistry Transport Model (ACTM). The comparisons suggest WRF–CO2simulation is able to capture large scale features in the observed variabilities, with varied ability at fine scales depending on representation of surface fluxes and meteorology around the observation sites. Analysis of CO2signals from individual flux components suggests that ocean flux has least contribution to the CO2variation (<10%). Four sites (Mt. Waliguan, Nainital, Cape Rama and Lulin) show dominance of biospheric flux over fossil flux to the CO2variation (>80%). CO2mixing ratios are found to be maximum in northern hemisphere (NH) winter over East Asia, while they are maximum in NH spring over Indian subcontinent. Observed peak-to-trough seasonal amplitude is lowest (4.5 ppm) for the site Bukit Koto Tabang, Indonesia and highest (29.5 ppm) for Shangdianzi in China. Statistical analysis from monthly mean CO2time series shows that correlation coefficient and normalised standard deviation with observations, are generally equal or better for the WRF–CO2than the coarser resolution ACTM. Study of synoptic scale CO2variations shows that the WRF–CO2is able to better resolve daytime signatures than those in the night. Year-to-year CO2variations of seasonal cycle amplitude is highest (~5 ppm) at Nainital, India compared to all other sites.

Inorganic and organic arsenic compounds in nature are methylated by biological action and released into the air, forming trimethylar-sine and dimethylarsine1–5. These compounds are oxidized in the air to dimethylarsinic acid and trimethylarsineoxide6and exist as particles7,8. In this study, we examine seasonal variations of methylarsenic compounds in airborne particulate matter to try to understand the characteristics of the methylation of arsenic in nature. In summer a high concentration of dimethyl and trimethyl forms of arsenic was observed, while in winter the levels were very low. This seasonal variation can be attributed to the different temperatures of the environment during these seasons. The activation energy of methylation of arsenic was estimated to be ∼12 kcal mol−1from Arrhenius plots and can be used to predict the behaviour of these methylarsenic compounds, which are considered to form an important portion of the arsenic present in airborne particulate matter.

We present a data set of atmospheric potential oxygen (APO = O2+ 1.1 × CO2) based on the atmospheric O2/N2and CO2measurements of flask samples collected at two monitoring stations in Japan and on commercial cargo ships sailing between Japan and U.S./Canada and Australia/New Zealand. Since APO is invariant with respect to the terrestrial biotic exchange, its variation mainly reflects the spatiotemporal distribution in the air‐to‐sea gas exchange. From the observed APO for the years 2002–2008, we find: (1) elevated annual mean values near the equator, (2) elevated annual mean values and large seasonal amplitudes in the northwestern North Pacific, and (3) a deep trough of low annual mean values at latitudes 20–40°N in the Western Pacific. In addition, latitudinal distributions in the timing of the observed seasonal maximum and minimum show asymmetric patterns across the equator. Comparing these observations with a series of simulated APO generated in the NIES99 atmospheric transport model driven by a set of climatological oceanic O2and CO2flux fields, we find a good agreement except for the observed deep trough at the midlatitude. Simulations with different transport mechanisms and fluxes reveal that the seasonal covariation between oceanic O2flux and atmospheric transport contribute significantly to the observed APO variations in the northern North Pacific; also the seasonal variation in the meridional transport affects the latitudinal difference in the seasonal cycle. The observed latitudinal gradient of the annual mean APO in the Southern Hemisphere is better reproduced by the model based on the recently revised ocean CO2flux distribution than that based on the previous CO2flux distribution. The observed APO trough at 36°N in the Western Pacific is about 10 per meg lower than the simulation with the more recent pCO2data, suggesting the existence of additional APO sinks in that latitudinal region. Indeed, a model simulation performed with an additional ocean O2sink flux of about 30 Tmol yr−1within the region (30–50°N, 120–180°E) reproduces considerably well the observed APO trough. Highly precise distribution of APO in the Western Pacific was investigatedAir‐sea CO2 and O2 exchange fluxes in the Pacific region were examinedContributions of atmospheric transport to APO variations were examined