Jiang F.,Nanjing University |
Zhou P.,Meteorological Bureau |
Liu Q.,Hong Kong Polytechnic University |
Wang T.,Nanjing University |
And 2 more authors.
Journal of Atmospheric Chemistry | Year: 2012
In this study, we investigate the springtime O3 formation over East China (April 2008) using the Weather Research and Forecasting Model with Chemistry (WRF/Chem). A simple process analysis scheme is added to WRF/Chem, which could calculate the contributions of photochemical and physical processes to O3 formation. WRF/Chem calculates the hourly 3-D O3 mixing ratios, photochemical O3 production rates (CPR) and physical processes contribution rates (PCR) on a two nested domain system, with inner domain focusing on East China. Model evaluation shows that the modeled results agree relatively well with the observations. On the ground level, the high O3 mixing ratios (>45 ppbv) are located over Fujian and Jiangxi provinces. The O3 levels over the Yangtze River Delta (YRD) and northern Jiangsu are low (<30 ppbv). The distribution patterns of CPR and PCR over East China reveal that the high O3 mixing ratios over Jiangxi and Fujian are caused by both local photochemical generation and regional transport, while the O3 concentrations over the YRD region are transported and diffused from surrounding areas. In addition, the contributions of biogenic and anthropogenic emissions as well as the regional transport from domain's upstream regions are discussed. On average, the biogenic and anthropogenic emissions account for 2.6 and 4.5 ppbv of daytime mean O 3 mixing ratios in East China, respectively. © 2012 Springer Science+Business Media Dordrecht. Source
Mu Z.J.,Chongqing Three Gorges University |
Mu Z.J.,Southwest University |
Mu Z.J.,Source Point |
Huang A.Y.,Southwest University |
And 10 more authors.
Journal of Soil Science and Plant Nutrition | Year: 2013
Vegetable fields in China are characterized with intensive fertilization and cultivation, and their net effect on the global warming deserves attention. Greenhouse gas fluxes were thus measured, using a static closed chamber method, over approximately 18 months in two typical subtropical vegetable fields with different soil types and contrasting soil properties. Five consecutive crops were planted in one field and four in the other. Intensive fertilization consistently stimulated soil N2O emission, while imposed complicated impact on soil respiration with CO2 emission enhanced in one field and suppressed in the other field. The fertilizer-induced N2O emission factors (EFs) varied with individual crop phases and averaged 1.4 to 3.1% across the whole sampling period for different fields. The interaction of soil temperature and moisture could explain about 58% of the seasonal variation in the EFs. All the soils under different vegetable cropping systems were net sources of atmospheric radiative forcing and the net global warming potential over the entire study period ranged from 1,786 to 3,569 g CO2 equivalence m-2 for fertilized soils with net CO2 emission contributing 53 to 67% and N2O emission occupying the remaining 33 to 47%. © 2013 Chilean Society of Soil Science. Source
Lee X.,Nanjing University of Information Science and Technology |
Lee X.,Yale University |
Liu S.,Nanjing University of Information Science and Technology |
Xiao W.,Nanjing University of Information Science and Technology |
And 12 more authors.
Bulletin of the American Meteorological Society | Year: 2014
An eddy covariance (EC) network on Lake Taihu, a large and shallow lake in southeastern China, was reported. The network consists of five lake sites, representing different biological attributes, pollution status, and wind, wave patterns, and a land site near the lake shore. The data collected at Lake Taihu have been used to improve the lake model in NCAR's Community Land Model (CLM) system. Tests of the model for deep lakes reveal that the eddy thermal diffusivity given by the model is 1-2 orders of magnitude too low. It was found that for Lake Taihu the diffusivity should be adjusted downward by 92% in order for the model to reproduce successfully the observed diurnal variations in the lake surface temperature. The small eddy diffusivity suggests that unresolved vertical eddy motions are weak or absent at this large and shallow lake. Source
Sun X.,Health and Family Planning Commission |
Sun Q.,U.S. Center for Disease Control and Prevention |
Zhou X.,U.S. Center for Disease Control and Prevention |
Li X.,U.S. Center for Disease Control and Prevention |
And 3 more authors.
Science of the Total Environment | Year: 2014
Background: In 2013 southeast China suffered from an unusual high temperature, which had broken the heat records in the past 141. years. Few studies have examined the impact of heat waves on mortality in Asia. Objective: To estimate the impact of the heat wave in 2013 on mortality among the registered permanent residence population and identify susceptible subpopulations in Pudong New Area. Methods: To model the relationship between the maximum temperature and mortality, a quasi-poisson generalized additive model was applied using data from 1 January 2008 to 15 June 2013. Extrapolating the model the estimated daily expected number of deaths was calculated over the period of 16 June 2013 to 15 September 2013. Results: There were four heat waves in 2013, causing 167 (95% CI: 46-280) excess deaths in all-cause mortality, corresponding to an excess mortality of 10.51%. After the first two heat waves, the cumulative excess death counts gradually reduced to the level before the start of the heat waves. In contrast, the cumulative excess death numbers increased rapidly during the last two heat waves, without decreasing after the heat waves. Females (male: 10.43%, female: 11.79%) and people aged ≥ 80 years old (excess deaths were 129 (95% CI: 47-203) and excess mortality was 16.64%) were strongly affected by the heat waves. The excess mortalities of cardiovascular and respiratory disease were 22.34% and 20.68% respectively, which were higher than that of all-cause deaths. Conclusions: The 2013 heat wave had a significant impact on mortality even after the considered "mortality displacement". Females and people aged ≥. 80. years old were significantly vulnerable to the heat waves. The observed excess mortalities of cardiovascular and respiratory disease were higher than all-cause deaths. These results could provide scientific evidences for policy makers to frame heat wave-related prevention measures, which may help in reducing the mortality. © 2014 Elsevier B.V. Source
Wang Y.,Chinese Academy of Meteorological Sciences |
Qin J.,Meteorological Bureau |
Zhu L.,State Oceanic Administration
Advances in Meteorology | Year: 2015
Using station precipitation and reanalysis data, we examined the evolution of the large-scale circulations associated with the heavy rainfall event that occurred around July 21, 2012 (721 heavy rainfall). This study focuses on a role that the large-scale circulations named "the Okhotsk-Japan (OKJ) circulation pattern" played in causing the heavy rainfall case. We found that the 721 heavy rainfall occurred under a background of the OKJ circulation that persisted for about 10 days. However, the pattern was different from the normal OKJ circulation, for this circulation pattern accompanied a blocking high between the Ural Mountains and the Baikal Lake. This difference resulted from the seasonal change of the basic flow. The related Rossby wave propagated eastward during the persisting period of the dominated OKJ pattern. This caused the development of a low-pressure system around the Baikal Lake and the weakening of a ridge around the Okhotsk Sea. The slow evolution of the OKJ circulation created a favorable environment for the moisture transport to northern China, assisting in the generation of the 721 heavy rainfall. © 2015 Yafei Wang et al. Source