A Sensitivity Study of IAP AGCM to Radiation Changes: Climate Simulation of 125kyr and 115kyr before Present

The IAP AGCM was used to simulate the climate of 125kyr and 115kyr before present. We analysed the results and then studied the sensitivity of the model to the changes of radiation distribution induced by orbital parameter changes. The reasonability of the results was also discussed.

Interannual Changes of Land Surface Radiation Components in Loess Plateau and Their Responses to Climate Change

In this paper,land surface observation data at semi-arid climate and environmental observation station（ SACOL station） of Lanzhou University during 2006- 2012 and the data of Yuzhong meteorological station were used to analyze the responses of land surface radiation budget components to climate fluctuation,study the interannual variability of surface albedo,and discuss the feedback of various land surface process parameters on the interannual fluctuations of temperature and precipitation in Loess Plateau. According to the type of precipitation in Loess Plateau,the year was divided into winter and summer in order to get more significant interannual variability and correlation. The results showed that the trends of temperature and precipitation during 2006- 2012 were consistent with the warming and drying total trend in recent years in Loess Plateau. Shallow surface soil moisture and temperature showed a good response to temperature and precipitation,and the annual variation of summer half year had greater impact on the trend in the whole year. Incident solar radiation increase was major reason for climate warming in the Loess Plateau region.The combined effect of climatic factors was the reason for the change of surface albedo. Through the distinguish inquiry by winter and summer data,it was obtained that most correlations between summer radiation components and climatic factors have been improved,and partial correlations between winter radiation components and climatic factors have been increased.

Changes in Lymphocyte Reactivity to ModulatoryFactors Following Low DoseIonizing Radiation

Catecholamines (CA) and corticosterone (CS) exerted modulatory effect on the proliferative activity of splenic and thymic lymphocytes in response to mitogenic stimulation in vilro. Epinephrine (E) and norepinephrine (NE) potentiated proliferation in concentrations above 1 and 10 nmol/L, respectively, while CS showed a biphasic effect, stimulating proliferation at concentrations below 0.1 nmol/L and suppressing proliferation at concentrations above 10 nmol/L. Combination of CS with E, NE or both in an ineffective concentration of each (0.1 nmol/L ) showed stimulatory effect on the proliferative response of both splenic and thymic lympliocytes to Con A. Whole-body irradiation (WBI) of mice with 75 mGy incIeased the reactivity of splenic and thymic lymphocytes to Con A. It is reported for the first time in the present paper that the proliferative reactivity of splenic and thymic lymphocytes from low dose irradiated mice could be further increased in the presence of suboptimal concentrations of CS and E as well as suboptimal concentrations of phorbol myristate acetate (PMA ) and A23187. These findings may have significance in the mechanism of immunologic stimulation after low dose WBI

Efficiency Improvement of PV Generation System by Using Improved P ＆ O Method of MPPT

The conventional P ＆ O （perturb-and-observe） method, which is the most widely used as MPPT （maximum power point tracking） control, has the problem of low efficiency and unstable operation when solar radiation changes drastically. Aiming at this problem, this paper improves the conventional P ＆ O method to reduce the bad effect of solar radiation by shortening the sampling interval of PV module＇s output power while keeping the operating period unchanged. Experiments are conducted to study efficiency gains of improved method when solar radiation changes drastically. The result shows that, by this method, the efficiency of MPPT control can be increased 17% in average when PV module simulator is used and 20% at maximum when actual PV module is used, compared with the conventional P ＆ O method.

INFLUENCES OF DIURNAL CHANGE OF SOLAR RADIATION ON SIMULATED PROPERTIES OF SUMMER MONSOON

Comparative experiments with and without the diurnal change of solar radiation are made in this paper by use of an air-sea coupled 7-layer primitive equation modeling system in a zonal domain between 60°S and 60°N.The results show that the quasi-stationary patterns of the mean monsoon circulations are not evidently affected by the diurnal change of solar radiation.The main influences may come from the land-sea distribution and the orography.However,the inclusion of the diurnal change of solar radiation into the model system may improve the intensities of the simulated monsoon circulations both at the high and the low levels.It can influence the distributive pattern of precipitation to a larger extent.Without the diurnal change,precipitation in the interior of land would decrease and in the coastal regions it would increase.The changes of the soil temperature and the soil moisture are fairly correspondent to that of precipitation.The areas with increasing precipitation and the areas with decreasing precipitation are distributed in the wave form.As to the influences on the monsoon development,the results indicate that the diurnal change of solar radiation can speed up the development of the monsoon in the early stage.Therefore,the inclusion of the diurnal change of solar radiation can make the model equilibrium state to reach earlier.

Trends of the sunshine duration and diffuse radiation percentage on sunny days in urban agglomerations of China during 1960–2005

The long-term observational data of sunshine duration（SD） and diffuse radiation percentage（defined as diffuse solar radiation/total solar radiation, DRP） on sunny days during 1960–2005 were analyzed in 7 urban agglomerations and the whole of China. The results show that the sunny sunshine duration（SSD） has decreased significantly except at a few stations over northwestern China in the past 46 years. An obvious decrease of the SSD is found in eastern China, with the trend coefficients lower than-0.8. Accompanied by the SSD decline, the sunny diffuse radiation percentage（SDRP） in most stations shows obvious increasing trends during the 46 years. The averaged SDRP over China has increased 2.33%per decade, while the averaged SSD shows a decrease of-0.13 hr/day per decade. The correlation coefficient between SDRP and SSD is-0.88. SSD decreased over urban agglomerations（small to large city clusters） in the past 46 years, especially in large cities and medium cities, due to the strong anthropogenic activities and air pollution represented by aerosol option depth（AOD） and tropospheric column NO2（Tro NO2）. On the regional scale, SSD has an opposite trend from SDRP during 1960 to 2005, and the variation trends of regional mean values of SSD and SDRP in southeastern China are more pronounced than those in northwestern China.

Analysis of the Initial Stage Intracloud Lightning Using the Pulse Location Technique Based on the Fast Electric Field Change

Academy of Sciences,Beijing 100029 2 Lanzhou University,Lanzhou 730000 3 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences,Lanzhou 730000 4 Nanjing University of Information Science＆Technology,Nanjing 210044 Using both fast and slow electric field change sensors and field mill,multi-station observations on lightning flashes over China inland plateau areas were conducted during the summer of 2004.All of the stations were synchronized by GPS with a time-resolution of±50 ns.Using the different time of arrival（DTOA）and based on the fast electric field change sensor,a lightning radiation location technique was developed.Radiation pulses in the initial stages of five intracloud（IC）lightning discharges which occurred on 20 August were analyzed.The results indicate that the technique developed could effectively locate the lightning radiation sources.Furthermore,the lightning discharges were compared with the Doppler radar data.The results show that the radiation sources were well associated with the storm development.When the storm was at the mature stage with an echo top of about 10.9 km,the radiation sources ranged from 5.2 to 8.3 km above mean sea level;when the storm gradually became weaker,with echo top of about 7.9 km,the radiation sources ranged from 3.0 to 5.9 km.In particular,one of the IC lightning discharges ranged from 3.0 to 4.9 km during the dissipation stage of the storm.The results also indicate that the radiation sources were closely associated with the high reflectivity region（25–50 dBZ）of the storm,which,to some extent,demonstrates the reliability of the location results,thereby showing that multi-station observations of fast electric field change sensors could be a useful tool for monitoring the storm development.Location errors from radiation sources were also compared with the radar data and the results of a simple simulation.It was found that the errors were getting smaller when the radiation sources approached the center of the detection network, and vice versa.Compared with the limited experimental observations,the simulation results were found capable of effectively reflecting the location errors.