Stratospheric profiles of the mean age of air estimated from cryogenic air samples acquired during a field campaign over Indonesia, the Coordinated Upper-Troposphere-to-Stratosphere Balloon ...Experiment in Biak, were investigated using the boundary impulse evolving response (BIER) method and Lagrangian backward trajectories, with the aid of an atmospheric general circulation model-based chemistry transport model (ACTM). The ACTM provides realistic meteorological fields at 1-hour intervals by nudging toward the European Centre for Medium- Range Weather Forecasts Reanalysis-Interim. Since the BIER method is capable of taking unresolved diffusive processes into account, while the Lagrangian method can distinguish the pathways the air parcels took before reaching the sample site, the application of the two methods to the common transport field simulated by the ACTM is useful in assessing the CO2- and SF6-derived mean ages. The reliability of the simulated transport field has been verified by the reproducibility of the observed CO2, SF6, and water vapor profiles using the Lagrangian method. The profile of CO2 age is reproduced reasonably well by the Lagrangian method with a small young bias being consistent with the termination of trajectories in finite length of time, whereas the BIER method overestimates the CO2 age above the altitude of 25 km, possibly due to high diffusivity in the transport model. In contrast, the SF6 age is only reproducible in the lower stratosphere, and far exceeds the estimates from the Lagrangian method above the altitude of 25 km. As air parcels of mesospheric origin are excluded in the Lagrangian age estimation, this discrepancy, together with the fact that the observed SF6 mole fractions are much lower than the trajectory-derived values in this height region, supports the idea that the stratospheric air samples are mixed with SF6-depleted mesospheric air, leading to overestimation of the mean age.
As colour vision deficiency (CVD) is hereditary and incurable, it is widely known that people with CVD do not need treatment, but rather appropriate social accommodation. Regardless, some ...practitioners of complementary and alternative medicine have attempted to treat CVD. By investigating the rhetorical strategies of these therapists who allegedly treated CVD in Japan in the 1970s and 1980s, this study analyses how they justified treating CVD despite the widespread prevalence of social accommodation. These therapists argued that treatment alone could remove the 'dirty' vision of people with CVD, even though it was clear that any trouble because of CVD can be mitigated through social accommodation. This finding has implications for understanding the history of the emancipation of people with CVD, enhancing the disability rights movement to refute the medical model that discounts the effects of social accommodation, and identifying how it demarcates itself from social accommodation.
People with colour vision deficiency find it hard to recognise the difference between colours such as red and green. They have faced some restrictions in education and employment because of their different eyesight.
They need appropriate social accommodation, including icons, symbols, and appropriate colour schemes, that decrease the difficulties from having colour vision deficiency without treatment.
However, therapists of complementary and alternative medicine have tried to treat colour vision deficiency, especially in Japan, even when social accommodations were available.
By analysing the discourse among the therapists, this study examines how this treatment was justified. The results show that the therapists argued that eyesight of people with colour vision deficiency was 'dirty' and can be improved, not by social accommodations, but by treatment.
This study is important because the findings reveal how to refute cure-oriented discourse, which stigmatises impairments to justify treatment.
Accurate estimates of the carbon dioxide (CO
2
) fluxes at the earth’s surface are imperative for comprehending the carbon cycle mechanisms and providing reliable global warming predictions. ...Furthermore, they can also provide valuable science-based information that will be helpful in reducing human-induced CO
2
emissions. Inverse analysis is a prominent method of quantitatively estimating spatiotemporal variations in CO
2
fluxes; however, it involves a certain level of uncertainty and requires technical refinement, specifically to improve the horizontal resolution so that local fluxes can be compared with other estimates made at the regional or national level. In this study, a novel set of inversion schemes was incorporated into a state-of-the-art inverse analysis system named NISMON-CO
2
. The introduced schemes include a grid conversion, observational weighting, and anisotropic prior error covariance, the details of which are described. Moreover, pseudo-observation experiments were performed to examine the effect of the new schemes and to assess the reliability of NISMON-CO
2
for long-term analysis with practical inhomogeneous observations. The experiment results evidently demonstrate the advantages of the grid conversion scheme for high-resolution flux estimates (1° × 1°), with notable improvements being achieved through the observational weighting and anisotropic prior error covariance. Furthermore, the estimated seasonal and interannual variations in regional CO
2
fluxes were confirmed to be reliable, although some potential bias in terms of global land–ocean partitioning was observed. Thus, these results are useful for interpreting the flux variations that result from real-observation inverse analysis by NISMON-CO
2
ver. 2021.1.
Systematic measurements of the atmospheric Ar∕N2
ratio have been made at ground-based stations in Japan and Antarctica since
2012. Clear seasonal cycles of the Ar∕N2 ratio with summertime maxima
were ...found at middle- to high-latitude stations, with seasonal amplitudes
increasing with increasing latitude. Eight years of the observed Ar∕N2
ratio at Tsukuba (TKB) and Hateruma (HAT), Japan, showed interannual
variations in phase with the observed variations in the global ocean heat
content (OHC). We calculated secularly increasing trends of 0.75 ± 0.30
and 0.89 ± 0.60 per meg per year from the Ar∕N2 ratio observed at
TKB and HAT, respectively, although these trend values are influenced by
large interannual variations. In order to examine the possibility of the
secular trend in the surface Ar∕N2 ratio being modified significantly
by the gravitational separation in the stratosphere, two-dimensional model
simulations were carried out by arbitrarily modifying the mass stream
function in the model to simulate either a weakening or an enhancement of
the Brewer–Dobson circulation (BDC). The secular trend of the Ar∕N2
ratio at TKB, corrected for gravitational separation under the assumption of
weakening (enhancement) of BDC simulated by the 2-D model, was 0.60 ± 0.30 (0.88 ± 0.30) per meg per year. By using a conversion factor of
3.5 × 10−23 per meg per joule by assuming a one-box ocean with a temperature
of 3.5 ∘C, average OHC increase rates of 17.1 ± 8.6 ZJ yr−1 and 25.1 ± 8.6 ZJ yr−1 for the period 2012–2019 were
estimated from the corrected secular trends of the Ar∕N2 ratio for the
weakened- and enhanced-BDC conditions, respectively. Both OHC increase
rates from the uncorrected- and weakened-BDC secular trends of the Ar∕N2
ratio are consistent with 12.2 ± 1.2 ZJ yr−1 reported by ocean
temperature measurements, while that from the enhanced-BDC is outside of the
range of the uncertainties. Although the effect of the actual atmospheric
circulation on the Ar∕N2 ratio is still unclear and longer-term
observations are needed to reduce uncertainty of the secular trend of the
surface Ar∕N2 ratio, the analytical results obtained in the present
study imply that the surface Ar∕N2 ratio is an important tracer for
detecting spatiotemporally integrated changes in OHC and BDC.
The accuracy of chemical tracer simulations by atmospheric general circulation model (AGCM)-based chemistry-transport models (ACTMs) depends on the quality of AGCM transport properties, even when the ...meteorology is nudged towards the reanalysis fields. Here we show that significant improvements in tracer distribution are achieved when hybrid vertical coordinate is implemented in MIROC4.0 AGCM, compared to its predecessors AGCM5.7b based on sigma coordinate. Only explicitly resolved gravity waves are propagated into the stratosphere in MIROC4-ACTM. The MIROC4-ACTM produces “age-of-air” up to about 5 years in the tropical upper stratosphere (∼1 hPa) and about 6 years in the polar middle stratosphere (∼10 hPa), in agreement with observational estimates. Comparisons of MIROC4-ACTM simulation with observed sulphur hexafluoride (SF6) in the troposphere also show remarkable improvements over the AGCM57b-ACTM simulation. MIROC4-ACTM is characterized by weaker convective mass flux and thus older age of air in the tropical troposphere, relative to AGCM57b-ACTM. The role of convective transport on tracer simulations is depicted using vertical cross-sections of 222Rn (radon) distributions. Both the ACTM versions show similar results when compared with 222Rn measurements at remote sites. All aspects of tracer transport in MIROC4-ACTM is promising for inverse modelling of greenhouse gases sources and sinks at reduced bias.
Temporal variations of atmospheric radon-222 (222Rn) observed at four Japan Meteorological Agency stations in Japan by the Meteorological Research Institute were analyzed using an online Global ...Spectral Atmosphere Model-Transport Model (GSAM-TM). Monthly and diurnal variations and a series of synoptic high-222Rn events were extracted from 5 years to 12 years of 222Rn observations during 2007–2019. Observed seasonal patterns of winter maxima and summer minima, driven mainly by monsoons, were well reproduced by the GSAM-TM based on existing 222Rn emission inventories, but their absolute values were generally underestimated, indicating that our understanding of 222Rn emission processes in East Asia is lacking. The high-resolution model (∼ 60 km mesh) demonstrated that observed consecutive high-222Rn peaks at several-hour timescales were caused by two 222Rn streams from different regions and were not well resolved by the low-resolution model (∼ 200 km mesh). GSAM-TM simulations indicate that such cold-front-driven events are sometimes accompanied by complicated three-dimensional atmospheric structures such as stratospheric intrusion over the front, significantly affecting distributions of atmospheric components. A new calculation approach using hourly 222Rn values normalized to daily means was used to analyze the diurnal 222Rn cycle, allowing diurnal cycles in winter to be extracted from 222Rn data that are highly variable due to sporadic continental 222Rn outflows, which tend to obscure the diurnal variations. Normalized diurnal cycles of 222Rn in winter are consistent between observations and model simulations, and seem to be driven mainly by diurnal variations of planetary boundary layer height (PBLH). These results indicate that 222Rn in the near-surface atmosphere, transported from remote source regions, could vary diurnally by up to 10 % of the daily mean mainly owing to local PBLH variations, even without significant local 222Rn emissions.
This study assessed historical changes in emissions of nitrous oxide (N
2
O), a potent greenhouse gas and stratospheric ozone-depleting substance, from the soils of East Asia to the atmosphere. A ...process-based terrestrial ecosystem model (VISIT) was used to simulate the nitrogen cycle and associated N
2
O emissions as a function of climate, land use, atmospheric deposition, and agricultural inputs from 1901 to 2016. The mean regional N
2
O emission rate in the 2000s was estimated to be 2.03 Tg N
2
O year
−1
(1.29 Tg N year
−1
; approximately one-third from natural ecosystems and two-thirds from croplands), more than triple the rate in 1901. A sensitivity analysis suggested that the increase of N
2
O emissions was primarily attributable to the increase of agricultural inputs from fertilizer and manure. The simulated N
2
O emissions showed a clear seasonal cycle and interannual variability, primarily in response to meteorological conditions and nitrogen inputs. The spatial pattern of the simulated N
2
O emissions revealed hot spots in agricultural areas of China, South Korea, and Japan. The average N
2
O emission factor (emission per unit nitrogen input) was estimated to be 1.38%, a value comparable to previous estimates. These biogeochemical modeling results will facilitate identifying ways to mitigate global warming and manage agricultural practices in this region.
A terrestrial ecosystem model, called the Vegetation Integrative Simulator for Trace gases model (VISIT), which fully integrates biogeochemical carbon and nitrogen cycles, was developed to simulate ...atmosphere-ecosystem exchanges of greenhouse gases (CO₂, CH₄, and N₂O), and to determine the global warming potential (GWP) taking into account the radiative forcing effect of each gas. The model was then applied to a cool-temperate deciduous broad-leaved forest in Takayama, central Japan (36°08′N, 137°25′E, 1420 m above sea level). Simulations were conducted at a daily time step from 1948 to 2008, using time-series meteorological and nitrogen deposition data. VISIT accurately captured the carbon and nitrogen cycles of this typical Japanese forest, as validated by tower and chamber flux measurements. During the last 10 years of the simulation, the model estimated that the forest was a net greenhouse gas sink, having a GWP equivalent of 1025.7 g CO₂ m⁻² y⁻¹, most of which (1016.9 g CO₂ m⁻² y⁻¹) was accounted for by net CO₂ sequestration into forest biomass regrowth. CH₄ oxidation by the forest soil made a small contribution to the net sink (11.9 g CO₂-eq. m⁻² y⁻¹), whereas N₂O emissions were a very small source (3.2 g CO₂-eq. m⁻² y⁻¹), as expected for a volcanic soil in a humid climate. Analysis of the sensitivity of GWP to changes in temperature, precipitation, and nitrogen deposition indicated that warming temperatures would decrease the size of the sink, mainly as a result of increased CO₂ release due to increased ecosystem respiration.
Methane (CH4) plays important roles in atmospheric chemistry and short-term forcing of climate. A clear understanding of atmospheric CH4’s budget of emissions and losses is required to aid ...sustainable management of Earth’s future environment. We used an atmospheric chemistry-transport model (JAMSTEC’s ACTM) for simulating atmospheric CH4. A global inverse modeling system has been developed for estimating CH4 emissions from 53 land regions for 2002-2012 using measurements at 39 sites. An ensemble of 7 inversions is performed by varying a priori emissions. Global net CH4 emissions varied between 505-509 and 524-545 Tg yr-1 during 2002-2006 and 2008-2012, respectively (ranges based on 7 inversion cases), with a step like increase in 2007 in agreement with atmospheric measurements. The inversion system did not account for interannual variations in OH radicals reacting with CH4 in the atmosphere. Our results suggest that the recent update of the EDGAR inventory (version 4.2FT2010) overestimated the global total emissions by at least 25 Tg yr-1 in 2010. The increase in CH4 emission since 2004 originated in the tropical and southern hemisphere regions, coinciding with an increase in non-dairy cattle stocks by ∼10 % from 2002 (with 1056 million heads) to 2012, leading to ∼10 Tg yr-1 increase in emissions from enteric fermentation. All 7 ensemble cases robustly estimated the interannual variations in emissions, but poorly constrained the seasonal cycle amplitude or phase consistently for all regions due to the sparse observational network. Forward simulation results using both a priori and a posteriori emissions are compared with independent aircraft measurements for validation. Based on the results of the comparison, we reject the upper limit (545 Tg yr-1) of global total emissions as 14 Tg yr-1 too high during 2008-2012, which allows us to further conclude that the increase in CH4 emissions over the East Asia (mainly China) region was 7-8 Tg yr-1 between the 2002-2006 and 2008-2012 periods, contrary to 1-17 Tg yr-1 in the a priori emissions.
The powerful El Niño event of 2015-2016 - the third most intense since the 1950s - has exerted a large impact on the Earth's natural climate system. The column-averaged CO2 dry-air mole fraction ...(XCO2) observations from satellites and ground based networks are analyzed together with in situ observations for the period of September 2014 to October 2016. From the differences between satellite (OCO-2) observations and simulations using an atmospheric chemistry-transport model, we estimate that, relative to the mean annual fluxes for 2014, the most recent El Niño has contributed to an excess CO2 emission from the Earth's surface (land+ocean) to the atmosphere in the range of 2.4+/-0.2 PgC (1 Pg = 10(exp 15) g) over the period of July 2015 to June 2016. The excess CO2 flux is resulted primarily from reduction in vegetation uptake due to drought, and to a lesser degree from increased biomass burning. It is about the half of the CO2 flux anomaly (range: 4.4-6.7 PgC) estimated for the 1997/1998 El Niño. The annual total sink is estimated to be 3.9+/-0.2 PgC for the assumed fossil fuel emission of 10.1 PgC. The major uncertainty in attribution arise from error in anthropogenic emission trends, satellite data and atmospheric transport.
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