Ben-Jei Tsuang

The Madden‐Julian Oscillation in a warmer world

Global warmings impact on the Madden-Julian Oscillation (MJO) is assessed using one of the few models capable in reproducing its key features. In a warmer climate predicted for the end of the century, the MJO increases in amplitude (by ~30%) and frequency, showing a more circumglobal propagation tendency. The MJO spatial extent becomes enhanced, deeper, and more zonally extended but meridionally confined. A stronger vertical tilting structure in diabatic heating, moisture, and convergence fields is seen. Our findings indicate that these changes result from an intensification of the frictional wave-conditional instability of the second kind mechanism via the coupling of dynamical and thermodynamic response to the warming. The warming and moistening of the mean state contribute to the enhanced deep convective heating, driving a stronger-forced Kelvin wave-like perturbation. This reinforces the frictional low-level convergence, leading to larger shallow convective heating and therefore to a faster development and enhancement of the deep convection in the MJO.

Model structure and land parameter identification: An inverse problem approach

[1] Model structures for the parameterization of energy and water exchanges between the atmosphere and the land are explored, and the parameters are identified. Minimizing the root-meansquare error (RMSE) of the calculated air temperature is used as the objective function. Eight parameters are determined within 14 iterations over two urban sites in a subtropical island. The identified values of these parameters can be compared with those listed in the literature. The results show that (1) a proper choice of canopy resistance is important in determining the mean temperature; (2) using a scheme to calculate stomatal resistance from vegetated areas shows improvements in simulating the diurnalvariations of the temperature, decreasing the RMSE by0.4K; (3) using a scheme to accommodate the effect of evaporation from skin reservoirs during rain events shows improvements in determining the temperature immediately after the rain, decreasing the RMSE by 0.1 K; (4) while incorporating a soil-moisture availability function does not show improvement in the model performanceunless anextra water table variable isadded, which decreases the RMSE by 0.03 K. Incorporating all of the above model structures, the calculated hourly air temperature has a correlation coefficient of as high as 0.97 with a RMSE of 1.4 K. INDEXTERMS: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 1818 Hydrology: Evapotranspiration; 1833 Hydrology: Hydroclimatology; 3307 Meteorology and Atmospheric Dynamics: Boundary layer processes; 3322 Meteorology and Atmospheric Dynamics: Land/atmosphere interactions; KEYWORDS: inverse problem, parameter identification, Taipei, Hualien, evapotranspiration, land surface processes

Quantification on source/receptor relationship of primary pollutants and secondary aerosols from ground sources. Part II. Model description and case study

A Circuit Trajectory transfer-coefficient model (CTx) is developed in this study based on the parameterization presentedin a companion paper (Tsuang et al., Atmos. Environ., in this issue). CTx was testedby applying it to Metropolitan Taipei for the entire year 1998. The model was calibrated in January and verified throughout the year. The results indicate that the correlation coefficients (r) for daily concentrations of CO, NOx ,S O 2 ,P M 2.5 andPM 10 were 0.75, 0.69, 0.39, 0.55 and0.55, respectively, with biases of the means ranging from 0% to 20% d uring the verification period. According to contour plots of contributed concentrations to the city, ‘‘teleconnections’’ between source emissions and their contributions to the city can be identified. In addition, the model captures most of the dust episodes except during the periods of Asian dust storms. The sensitivity analysis shows that the calculated PM10 concentration is most sensitive to its dry deposition velocity as well as its emission rate. A more thorough study on the deposition velocity of PM2.5 is suggested. r 2002 Elsevier Science Ltd. All rights reserved.

Application of circuit model for Taipei City PM10 simulation

This study simulated PM10 concentrations in Taipei City from September 1990 to June 1992, by using a circuit model developed by Tsuang and Chao. Simulation results demonstrated that the scheme performs better than a box model. The correlation coefficient between observed and predicted values was 0.61 with a standard error of 60 μg m-3. The mean treatment score of successful predictions of high PM10 concentrations (exceeding 125 μg m-3) was 58%. Fine particulates were found to be the major contributor toward hazardous air quality, under a stable, low wind speed and rainless atmosphere. In addition, the ill-mixed factor was found to be zero. The circuit model is close to a box model equation under an unstable atmosphere where the mixing height is much higher than the surface layer.

Quantification on the source/receptor relationship of primary pollutants and secondary aerosols by a Gaussian plume trajectory model: Part III—Asian dust-storm periods

Characteristics of pollutants at heights in the top of the Planetary Boundary Layer (PBL) are collected and used in a local-scale model. A subsidence mechanism is developed to quantify the concentration fraction from the top PBL to simulate PM concentration during Asian dust-storm (ADS) periods. The results show that using the data measured at a mountain station, which is very vulnerable to ADS, as the top boundary conditions for the air quality model can capture all the PM2.5 episodes due to local sources and ADS events, at a low-altitude urban station. The correlation coefficient (r2) of daily PM2.5−10 concentration has increased from 0.17 to 0.62 by incorporating the subsidence mechanism, and that of PM2.5 increases as well. The model results of nitrate, sulfate and ammonium aerosol in fine radii can be compared with observations. According to our analysis, five out of eight PM2.5 or PM10 episode days occurred on ADS days in the past 4 years (1999–2002). During ADS episodes in 2000, 12% of PM2.5 and 53% of PM2.5−10 were from ADS dust. In addition, two dry deposition algorithms are evaluated; the algorithm of Seinfeld and Pandis (Atmospheric Chemistry and Physics from Air Pollution to Climate Change, Wiley, New York, 1998, 1057pp.) is suggested in this case study.

Development of a circuit model to describe the advection-diffusion equation for air pollution

A circuit model for calculating pollutant concentration from an area source is derived. This model includes various loss, production and transfer terms and can be used by grid modellers seeking to build a more sophisticated description of the PBL. After analysis of exchange/removal processes operating in the PBL by using the circuit model, we find that the near ground steady-state concentration is close to max(q0l2ule, Cb) where q0 is emission rate, l the length of an area source, u wind speed, le an effective mixing length, and Cb upwind concentration. The value of q0l2ule increases proportionally with the length of an area source and inversely with wind speed until it reaches q0Vd during rainless time and q0Λle during raining time. Vd is dry deposition rate, and A scavenging coefficient. The worst air quality occurs under stable atmosphere with low wind speed and rainless conditions. However, it might take more than a day to reach such a high concentration in a stable atmosphere.

Adult atopic dermatitis and exposure to air pollutants—a nationwide population-based study

BACKGROUND There is a trend toward an increased worldwide prevalence of allergic diseases. It is speculated that industrialization with resultant air pollution plays a role. However, there are sparse epidemiologic data on the relation between air pollution and atopic dermatitis (AD) in adults. OBJECTIVE To investigate the relation between exposure to air pollutants and adult AD in a cross-sectional study based on data from the National Health Insurance Research Database in Taiwan. METHODS We identified 1,023 adult patients with AD and 4,092 age- and sex-matched controls without allergic diseases in 2011. Using data from 71 Environmental Protection Agency monitoring stations across Taiwan, levels of exposure to air pollutants were determined by the location of a subjects place of residence. Multivariate logistic regression analysis, adjusted for age, sex, levels of urbanization, and family income, was performed. RESULTS We found an association between particulate matter <2.5 μm in diameter or the Pollutant Standards Index (the highest sub-index of the concentrations of 5 main air pollutants after transformation) and the development of adult AD. The adjusted odds ratios were 1.05 (95% confidence interval 1.02-1.08) and 1.02 (95% confidence interval 1.01-1.03), respectively. CONCLUSION These results demonstrated that air pollution, represented by particulate matter <2.5 μm in diameter or the Pollutant Standards Index, was modestly associated with the development of AD in adults.

Tropical SST forcing on the anomalous WNP subtropical high during July–August 2010 and the record-high SST in the tropical Atlantic

Abstract In summer of 2010, the western North Pacific subtropical high (WNPSH) was extremely strong and exhibited unusual westward extension, which resulted in record-breaking warmth in Japan and considerably below-normal and westward-shifted tropical cyclone activity in the western North Pacific (WNP). Although a moderate La Niña occurred, the sea surface temperature (SST) in the northern Indian Ocean (NIO) and tropical Atlantic (TA) was considerably high. In this study, we argued that the La Niña cold SST alone was not sufficient to maintain the strong WNPSH of 2010, and that the unusually warm SSTs in the NIO and TA markedly contributed to the enhancement and westward shift of the WNPSH in the boreal summer of that year. We focused on the effects of sea surface temperature anomalies in the tropical Atlantic (TA-SSTAs), which have been seldom explored and are poorly understood compared with the effects of SSTAs in the tropical Pacific and NIO. The warm TA-SST forced a westward-extending overturning circulation, with a sinking branch over the central Pacific Ocean, which produced a remote response similar to the La Niña condition and enhanced the WNPSH. The warm TA-SST also induced the cyclonic anomaly in the tropical eastern North Pacific, a distinct phenomenon not observed in a canonical La Niña event. Furthermore, we demonstrated that the anomalous near-surface circulation associated with the negative North Atlantic Oscillation might play a more dominant role than that of the 2009 El Niño in inducing the record-high SST in the TA in 2010.

Cumulative body burdens of polycyclic aromatic hydrocarbons associated with estrogen bioactivation in pregnant women: protein adducts as biomarkers of exposure.

The objective of this research was to simultaneously analyze protein adducts of quinonoid metabolites of naphthalene and endogenous estrogen in serum albumin (Alb) derived from healthy pregnant women in Taiwan and to explore the correlations among them. The isomeric forms of cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) as well as estrogen quinones, including estrogen-2,3-quinones (E2-2,3-Q) and estrogen-3,4-quinones (E2-3,4-Q), are characterized after adduct cleavage. Results showed that the median levels of cysteinyl adducts of 1,2-NPQ and 1,4-NPQ on serum albumin were 249-390 and 16.0–24.8 pmol g−1, respectively. Logged levels of 1,2-NPQ-Alb were correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001). Cysteinyl adducts of E2-2,3-Q-1-S-Alb, E2-2,3-Q-4-S-Alb, and E2-3,4-Q-2-S-Alb were detected in all subjects with median levels at 275-435, 162-288, and 197-254 pmol g−1, respectively. We also found a positive relationship between logged levels of E2-2,3-Q-4-S-Alb and those of E2-3,4-Q-2-S-Alb (r = 0.770, P < 0.001).We noticed that median levels of E2-2,3-Q-derived adducts (E2-2,3-Q-1-S-Alb plus E2-2,3-Q-4-S-Alb) in pregnant women were greater than those of E2-3,4-Q-2-S-Alb (∼2–3-fold). Taken together, this evidence lends further support to the theme that cumulative concentration of E2-3,4-Q is a significant predictor of the risk of breast cancer. Furthermore, we noticed that levels of 1,2-NPQ-Alb are positively associated with levels of E2-3,4-Q-2-S-Alb (r = 0.522, P < 0.001) and those of E2-2,3-Q-4-S-Alb (r = 0.484, P < 0.001). Overall, this evidence suggests that environmental exposure to polycyclic aromatic hydrocarbons may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen in humans.

Investigation of the cumulative body burden of estrogen-3,4-quinone in breast cancer patients and controls using albumin adducts as biomarkers

Both 17β-estradiol-2,3-quinone (E2-2,3-Q) and 17β-estradiol-3,4-quinone (E2-3,4-Q) are reactive metabolites of estrogen. Elevation of E2-3,4-Q to E2-2,3-Q ratio is thought to be an important indicator of estrogen-induced carcinogenesis. Our current study compared the cumulative body burden of these estrogen quinones in serum samples taken from Taiwanese women with breast cancer (n=152) vs healthy controls (n=75) by using albumin (Alb) adducts as biomarkers. Results clearly demonstrated the presence of cysteinyl adducts of E2-2,3-Q-4-S-Alb and E2-3,4-Q-2-S-Alb in all study population at levels ranging from 61.7-1330 to 66.6-1,590 pmol/g, respectively. Correlation coefficient between E2-2,3-Q-4-S-Alb and E2-3,4-Q-2-S-Alb was 0.610 for controls and 0.767 for breast cancer patients (p<0.001). We also noticed that in premenopausal subjects with body mass index (BMI) less than 27, background levels of E2-3,4-Q-2-S-Alb was inversely proportional to BMI with about 25% increase in E2-3,4-Q-2-S-Alb per 5 kg/m(2) decrease in BMI (p<0.001). In addition, we confirmed that mean levels of E2-3,4-Q-2-S-Alb in breast cancer patients were ∼5-fold greater than in those of controls (p<0.001). Overall, this evidence suggests that disparity in estrogen disposition and the subsequent elevation of cumulative body burden of E2-3,4-Q may play a role in the development of breast cancer.