Response of photosynthesis, morphology and growth of Hedysarum mongolicum seedlings to simulated precipitation change in Maowusu sandland

Response patters were investigated for seedlings of Hedysarum mongolicum, a dominant shrub in Maowusu sandland, to the simulated precipitation change by artificially controlling water supply at four levels. Plant growth characters, in terms of branch number and length, leaf number and area, and biomass, increased while water supply increased. However, the effect of water supply on leaf photosynthetic rate was not significant. Root/shoot biomass ratio significantly decreased with the increase of water supply, which was considered adaptive distribution of biomass investments in the different water supply. Water supply obviously affected branching patter. Branch section number, branch number and length of the same section enhanced as water supply increased. Branch number and length were clearly positive correlation with total and aboveground biomass in four water supply treatments. Branch character fully showed plant growth.

Changes of Precipitation Infiltration Recharge in the Circumstances of Coal Mining Subsidence in the Shen-Dong Coal Field,China

Coal mining subsidence is a universal environmental-geological problem in mining areas. By selecting the Shen-Dong coal mining subsidence area as the research field, this paper studies the changes in precipitation infiltration recharge in the circumstances of coal mining subsidence by means of field geological investigation and laboratory simulation experiments, which is expected to provide a scientific basis for eco-environmental restoration in the mining area. The results indicate that at the unstable stage of subsidence, three types of subsidence in the Shen-Dong mining area have positive effects on the precipitation infiltration recharge, and the type of full-thickness bedrock subsidence has the greatest influence. In the stable stage of subsidence, the precipitation infiltration process after long- term drought and the moisture migration in the aeration zone undergo three different stages： evaporation-infiltration before precipitation, infiltration-upward infiltration-infiltration during precipitation and evaporation-infiltration after precipitation. During a heavy rainfall infiltration process, the wetting front movement in fine sand, coarse sand and dualistic structure of fine-coarse sand consists of two stages： the stage of wetting front movement during precipitation, in which the wetting front movement distance has linear relationship with the depth, and the stage of wetting front movement after precipitation, in which the wetting front movement distance has the power function relationship with the depth. The wetting front movement velocity is influenced by the rainfall amount and the lithology in the aeration zone. However, as the depth increases, the movement velocity will decay exponentially.

Numerical Simulation on the Rainout-Removal of Sulfur Dioxide and Acidification of Precipitation from Stratiform Clouds

The rainout-removal of SO2 and the acidification of precipitation from stratiform clouds are simulated using a one-dimensional, time-dependent model, parameterized microphysically in which dissolution and dissociation of gaseous SO2 and H2O2, and oxidation reaction in aqueous phase are taken into account. The effects of dynamic factors, including updraft flow and turbulent transport, and the concentration of gaseous SO2 and H2O2 being transported into the clouds on pH value of the precipitation, the conversion rate S(Ⅳ)-S(Ⅵ) and the wet deposition rate of SO2 are discussed.

A simulation of winter wheat crop responses to irrigation management using CERES-Wheat model in the North China Plain

To improve efficiency in the use of water resources in water-limited environments such as the North China Plain（NCP）, where winter wheat is a major and groundwater-consuming crop, the application of water-saving irrigation strategies must be considered as a method for the sustainable development of water resources. The initial objective of this study was to evaluate and validate the ability of the CERES-Wheat model simulation to predict the winter wheat grain yield, biomass yield and water use efficiency（WUE） responses to different irrigation management methods in the NCP. The results from evaluation and validation analyses were compared to observed data from 8 field experiments, and the results indicated that the model can accurately predict these parameters. The modified CERES-Wheat model was then used to simulate the development and growth of winter wheat under different irrigation treatments ranging from rainfed to four irrigation applications（full irrigation） using historical weather data from crop seasons over 33 years（1981–2014）. The data were classified into three types according to seasonal precipitation： 〈100 mm, 100–140 mm, and 〉140 mm. Our results showed that the grain and biomass yield, harvest index（HI） and WUE responses to irrigation management were influenced by precipitation among years, whereby yield increased with higher precipitation. Scenario simulation analysis also showed that two irrigation applications of 75 mm each at the jointing stage and anthesis stage（T3） resulted in the highest grain yield and WUE among the irrigation treatments. Meanwhile, productivity in this treatment remained stable through different precipitation levels among years. One irrigation at the jointing stage（T1） improved grain yield compared to the rainfed treatment and resulted in yield values near those of T3, especially when precipitation was higher. These results indicate that T3 is the most suitable irrigation strategy under variable precipitation regimes for stable yield of winter wheat with maximum water savings in the NCP. The application of one irrigation at the jointing stage may also serve as an alternative irrigation strategy for further reducing irrigation for sustainable water resources management in this area.

Obtaining More Information about Precipitation Biases over East Asia from Hourly-Scale Evaluation of Model Simulation

The hourly summer precipitation simulations over East Asia by the Chinese Academy of Meteorological Science Climate System Model(CAMS-CSM)high-resolution Atmospheric Model Intercomparison Project(AMIP)runs(T255,~50 km)were evaluated based on the merged hourly precipitation product released by the China Meteorological Administration(CMA).The results show that the simulation biases are closely related to the topography,with the precipitation amount and frequency overestimated(underestimated),and duration of precipitation events being longer(shorter),over the western high-altitude(eastern plain)regions of China.Six regions with large discrepancies were further analyzed.In terms of the frequency-intensity structure,the overestimation of precipitation frequency is mainly due to the excessive simulated weak precipitation over the four regions with positive biases:the southern edge of the Tibetan Plateau(STP),the northeastern edge of the Tibetan Plateau(NETP),the eastern periphery of the Tibetan Plateau(EPTP),and the mountainous area of North China(NCM);while the underestimation of frequency is mainly due to the insufficient precipitation with moderate intensity over the two regions with negative biases:lower reaches of the Yangtze River(LYR)and the South China coast(SCC).Based on the duration-diurnal structure analysis,two kinds of precipitation events with different natures can be distinguished.The long-duration night to early morning precipitation events have a significant contribution to the precipitation amount biases for all the six key regions,and this kind of precipitation mainly affects the precipitation diurnal variation over the mountainous areas or steep terrain.Although the short-duration afternoon precipitation events only have a greater contribution to the precipitation amount biases over the SCC region,this kind of precipitation affects the diurnal variation over the NCM region and the two key regions with negative biases.Such a detailed hourly-scale evaluation is helpful for enriching the understanding of simulation biases and to further improve model performance.

NUMERICAL SIMULATIONS OF EFFECTS OF LAND SURFACE PROCESSES ON CLIMATE——IMPLEMENTING OF SSiB IN IAP/LASG AGCM AND ITS PERFORMANCE

This is an investigation of exchanges of energy and water between the atmosphere and the vegetated continents,and the impact of and mechanisms for land surface-atmosphere interactions on hydrological cycle and general circulation by implementing the Simplified Simple Biosphere (SSiB)model in a modified version of IAP/LASG global spectral general model(L9R15 AGCM). This study reveals that the SSiB model produces a better partitioning of the land surface heat and moisture fluxes and its diurnal variations,and also gives the transport of energy and water among atmosphere,vegetation and soil explicitly and realistically.Thus the coupled SSiB-AGCM runs lead to the more conspicuous improvement in the simulated circulation,precipitation,mean water vapor content and its transport.particularly in the Asian monsoon region in the real world than CTL-AGCM runs.It is also pointed out that both the implementation of land surface parameterizations and the variations in land surface into the GOALS model have greatly improved hydrological balance over continents and have a significant impact on the simulated climate. particularly over the massive continents. Improved precipitation recycling model was employed to verify the mechanisms for land surface hydrology parameterizations on hydrological cycle and precipitation climatology in AGCM. It can be argued that the recycling precipitation rate is significantly reduced,particularly in the arid and semi-arid region of the boreal summer hemisphere,coincident with remarkable reduction in evapotranspiration over the continental area.Therefore the coupled SSiB-AGCM runs reduce the bias of too much precipitation over land surface in most AGCMs,thereby bringing the simulated precipitation closer to observations in many continental regions of the world than CTL-AGCM runs.

Development of a computational tool for materials design

An integrated modeling tool coupling thermo- dynamic calculation and kinetic simulation of multicom- ponent alloys is developed under the framework of integrated computational materials engineering. On the basis of PandatTM software for multicomponent phase diagram calculation, the new tool is designed in an inte- grated workspace and is targeted to understand the com- position-processing-structure-property relationships of multicomponent systems. In particular, the phase diagram calculation module is used to understand the phase stability under the given conditions. The calculated phase equilib- rium information, such as phase composition and chemical driving force, provides input for the kinetic simulation. In this paper, the design of the modeling tool will be pre- sented and the calculation examples from the different modules will also be demonstrated.