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.

Characterization of fruit development and kernel component variation in candlenut （Aleurite moluccana）

Candlenut （Aleurites moluccana） is an important woody oil plant in the tropi-cal and subtropical regions. In the present study, characteristics of fruit development and changes of kernel components in candlenut during its fruiting season were investigated. It indicate that in southern China the growth and development period of candlenut fruit is from March to September. The period of rapid fruit growth occurs in late March to mid-May. Proteins and fats of mature nuts are accumulated in a critical period during the mid to late fruit development cycle. The optimal period for harvest is mid-August to late September. During fruit development, seed moisture content showed a trend of gradual decrease; it dropped from the initial 96.1% at the early stages of development to 16.9% at maturity. Sol-uble protein and sugar content showed a gradual increase during the initial and mid devel-opment period; it peaked in July and then decreased gradually. Starch content showed a rapid increase and accumulation during the initial and mid development period; it peaked in June, and then rapidly dropped. However, fat content increased continuously as the fruit developed and matured, and the maximum rate of lipid accumulation occurred in the mid-dle stage of fruit development. The preliminary conclusion of this study laid a foundation for making full use of candlenut fruit, especially as biofuels.

Geochemical weathering of aeolian sand and its palaeoclimatic implications in the Mu Us Desert,northern China,since the Late Holocene

In the semi-arid and arid regions of northern China,geochemical behavior of the aeolian deposit is closely related to climatic and environmental changes,which was used to reconstruct the past history of environmental evolution and possibly forcing mechanisms.However,the related result was still scarce due to the lack of detailed geochemical analysis results in the desert sediments.In the present study,we systematically analyzed the geochemical components and parameters of the paleo-aeolian sand dune and modern mobile sand deposits in the Mu Us Desert and discuss the climatic variation inferred from the paleo-aeolian sand dune during the past 4.2 ka BP.The results indicated that （1） geochemical composition of the sandy deposits were dominated by SiO_2,Al_2O_3 and Na_2O and the deposits probably originated from the widespread upper continental crust （UCC） and were formed by long-term weathering,transport and re-deposition;（2） these sandy deposits were subjected to weaker weathering or uneven weathering under cold and dry conditions,and had highly similar material sources and degrees of weathering and leaching in general;and （3） the direct OSL （Optically Stimulated Luminescence） dating ages and geochemical parameters from the palaeosol-aeolian sand dune indicated that the regional climate change experienced several typically cold and warm intervals.These intervals are 4.2,2.8 ka BP and Little Ice Age and Medieval Warm Period,which probably attributed to periodic variations of the Asian summer monsoonal strength and cold events of the northern Atlantic Ocean in low and high latitudes of the Northern Hemisphere.Our results suggest that the development of the sand dune in the Mu Us Desert provided a suitable archive for understanding the past local climatic change,which is linked to the global climatic change.