A Quick Report on a Dynamical Downscaling Simulation over China Using the Nested Model

This paper describes a dynamical downscaling simulation over China using the nested model system,which consists of the modified Weather Research and Forecasting Model(WRF)nested with the NCAR Community Atmosphere Model(CAM).Results show that dynamical downscaling is of great value in improving the model simulation of regional climatic characteristics.WRF simulates regional detailed temperature features better than CAM.With the spatial correlation coefficient between the observation and the simulation increasing from 0.54 for CAM to 0.79 for WRF,the improvement in precipitation simulation is more perceptible with WRF.Furthermore,the WRF simulation corrects the spatial bias of the precipitation in the CAM simulation.

Effects of Spatial Aggregation on Forest Landscape Model Simulation in Northeastern China

Issues of scale and aggregation become important when large range of space and time scales is considered in landscape models.However,identifying appropriate levels of aggregation to accurately represent the processes and components of ecological systems is challenging.A raster-based spatially explicit forest landscape model,LANDIS,was used to study the effects of spatial aggregation on simulated spatial pattern and ecological process in Youhao Forest Bureau of the Small Khingan Mountain in Northeastern China.The model was tested over 500 simulation years with systematically increased levels of spatial aggregation.The results show that spatial aggregation significantly influences the simulation of fire disturbance,species abundance,and spatial pattern.Simulated fire regime was relatively insensitive to grain size between 30.m and 270.m in the region.Spatial aggregation from 300.m to 480.m dramatically decreased fire return interval(FRI) and increased mean fire size.Generally,species abundance and its aggregation index(AI) remained higher level over simulation years at the fine-grained level of spatial aggregation than at coarser grains.In addition,the simulated forest dynamics was more realistic at finer grains.These results suggest that appropriate levels of spatial aggregation for the model should not be larger than 270m.

NUMERICAL STUDY OF INFLUENCE OF THE SSTA IN WESTERN PACIFIC WARM POOL ON RAINFALL IN THE FIRST FLOOD PERIOD IN SOUTH CHINA

A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is analyzed. According to the negative correlation between rainfall in the first flood period in South China (FFSC) and sea surface temperature anomalies (SSTA) in a key region in western Pacific warm pool (West Region), two sensitive experiments are designed to investigate the effects of the latter on the former and the possible physical mechanism is discussed. It is found that in cold water (warm water) years, the rainfall in South China (SC) is far more (less) than normal, while the rainfall in the middle and low reaches of the Yangtze River is relatively less (more). The best correlative area of precipitation is located in Guangdong Province. It matches the diagnostic result well. The effect of SSTA on precipitation of FFSC is realized through the abnormality of atmospheric circulation and tested by a P-σnine-layer regional climate model. Moreover, the simulated result of the P-σmodel is basically coincident with that of the CCM3.

Quantificational analysis and simulation of Technical Barriers to Trade with two country model

The Technical Barriers to Trade （TBT） is an important problem faced to the export of China. Based on the number differences of TBT notifications between countries, we propose the concept and computational method of the technical barrier coefficient. By means of price-production and price-demand functions, a trade model with a developed country and a developing country is designed. The available trade policies such as technical barriers, tariffs and export subsidies are simulated and analyzed. According to the simulation results, several trade strategies to come over technical barriers are suggested. These suggestions were provided to several export enterprises for their export strategy design.

论1998年印度核试验中的中国因素

1998年,印度连续进行了5次核试验。毫无疑问,在国际社会普遍要求防止核扩散,反对核试验和要求核裁军的大环境里,印度逆流而行公开进行核试验的原因是多方面的,本文将探究其中涉及到的中国因素。本文认为,印度进行公开核试验既有防范中国的意图,又有模仿中国的想法。另外,印度巧打中国牌为自己开脱罪行也是本文探讨的中国因素之一。

Soil Respiration of Biologically-Crusted Soils in Response to Simulated Precipitation Pulses in the Tengger Desert, Northern China

Soil respiration(SR) is a major process of carbon loss from dryland soils, and it is closely linked to precipitation which often occurs as a discrete episodic event. However, knowledge on the dynamic patterns of SR of biologically-crusted soils in response to precipitation pulses remains limited. In this study, we investigated CO_2 emissions from a moss-crusted soil(MCS) and a cyanobacterialichen-crusted soil(CLCS) after 2, 4, 8, 16, and 32 mm precipitation during the dry season in the Tengger Desert, northern China.Results showed that 2 h after precipitation, the SR rates of both MCS and CLCS increased up to 18-fold compared with those before rewetting, and then gradually declined to background levels; the decrease was faster at lower precipitation amount and slower at higher precipitation amount. The peak and average SR rates over the first 2 h in MCS increased with increasing precipitation amount, but did not vary in CLCS. Total CO_2 emission during the experiment(72 h) ranged from 1.35 to 5.67 g C m-2 in MCS, and from 1.11 to3.19 g Cm^(-2) in CLCS. Peak and average SR rates, as well as total carbon loss, were greater in MCS than in CLCS. Soil respiration rates of both MCS and CLCS were logarithmically correlated with gravimetric soil water content. Comparisons of SR among different precipitation events, together with the analysis of long-term precipitation data, suggest that small-size precipitation events have the potential for large short-term carbon losses, and that biological soil crusts might significantly contribute to soil CO_2 emission in the water-limited desert ecosystem.

Monitoring air pollution in China from geostationary satellite： A synthetic study using simulated observations

We simulated geostationary satellite observations to assess the potential for high spatial-and temporal-resolution monitoring of air pollution in China with a focus on tropospheric ozone(O_3), nitrogen dioxide(NO_2), sulfur dioxide(SO_2), and formaldehyde(HCHO). Based on the capabilities and parameters of the payloads onboard sun-synchronous satellites, we simulated the observed spectrum based on a radiative transfer model using a geostationary satellite model. According to optimal estimation theory, we analyzed the sensitivities and retrieval uncertainties of the main parameters of the instrument for the target trace gases. Considering the retrieval error requirements of each trace gas, we determined the major instrument parameter values(e.g., observation channel, spectral resolution, and signal-to-noise ratio). To evaluate these values, retrieval simulation was performed based on the three-dimensional distribution of the atmospheric components over China using an atmospheric chemical transportation model. As many as 90% of the experiments met the retrieval requirements for all target gases. The retrieval precision of total-column and stratospheric O_3 was 2%. In addition, effective retrieval of all trace gases could be achieved at solar zenith angles larger than 70°. Therefore, the geostationary satellite observation and instrument parameters provided herein can be used in air pollution monitoring in China. This study offers a theoretical basis and simulation tool for improving the design of instruments onboard geostationary satellites.

SYSTEM SIMULATION AND RELIABILITY ASSESSMENT OF CHINESE CARBON SEQUESTRATION MARKET

This study builds a simulation of Chinese carbon sequestration market(CSM) based on the Swarm platform and complex adaptive system(CAS) theory.The simulation results represent that the total assets and profits of the carbon sequestration project(CSP) buyer and seller are steadily on the increase in the carbon trading maxket.The market regulatory efficiency is determined by the market investment and the improvement of regulation policy.Furthermore,the real sample simulation of Sichuan Daduhe Forest CSP demonstrates that the profit of CSP traded in the CSM is higher than the profit from the transactions of outside exchange.It implies that establishing CSM is an effective way to improve the CSP business for investors and a positive action to response to global warming as well.Finally,this study applies an Analytic Hierarchy Process-Fuzzy Comprehensive Evaluation(AHPFCE) approach to evaluate the reliability of CSM simulation.It concludes that the CSM simulation is "more creditable",which indicates that the CSM simulation results can be used as a proxy to observe the market uncertainties.