Interannual variations of the air-sea carbon dioxide exchange in the different regions of the Pacific Ocean

Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by climatological monthly mean physical data and the climate-change run that is forced by interannually varying monthly mean physical data. Climatological monthly winds are used in both runs to calculate the coefficient of air-sea CO2 exchange. The analysis through the differences between the two runs shows that in the tropical Pacific the variation of export production induced by interannual variations of the physical fields is negatively correlated with that of the air-sea CO2 flux, while there is no correlation or a weak positive correlation in the subtropical North and South Pacific. It indicates that the variation of the physical fields can modulate the variation of the air-sea CO2 flux in converse ways in the tropical Pacific by changing the direct transport and biochemical process. Under the interannually varying monthly mean forcing, the simulated EOF 1 of the air-sea CO2 flux is basically consistent with that of sea surface temperature （SST） in the tropical Pacific, but contrary in the two subtropical Pacific Ocean. The correlation coefficient between the regionally integrated air-sea CO2 flux and area-mean SST shows that when the air-sea CO2 flux lags SST by about 5 months, the positive coefficient in the three regions is largest, indicating that in the tropical Pacific or on the longer time scale in the three regions, physical processes control the fiux-SST relationship.

Ensemble Simulation of Land Evapotranspiration in China Based on a Multi-Forcing and Multi-Model Approach

In order to reduce the uncertainty of offline land surface model （LSM） simulations of land evapotranspiration （ET）, we used ensemble simulations based on three meteorological forcing datasets [Princeton, ITPCAS （Institute of Tibetan Plateau Research, Chinese Academy of Sciences）, Qian] and four LSMs （BATS, VIC, CLM3.0 and CLM3.5）, to explore the trends and spatiotemporal characteristics of ET, as well as the spatiotemporal pattern of ET in response to climate factors over China's Mainland during 1982-2007. The results showed that various simulations of each member and their arithmetic mean （EnsAVlean） could capture the spatial distribution and seasonal pattern of ET sufficiently well, where they exhibited more significant spatial and seasonal variation in the ET compared with observation-based ET estimates （Obs_MTE）. For the mean annual ET, we found that the BATS forced by Princeton forcing overestimated the annual mean ET compared with Obs_MTE for most of the basins in China, whereas the VIC forced by Princeton forcing showed underestimations. By contrast, the Ens_Mean was closer to Obs_MTE, although the results were underestimated over Southeast China. Furthermore, both the Obs_MTE and Ens_Mean exhibited a significant increasing trend during 1982-98; whereas after 1998, when the last big EI Nifio event occurred, the Ens_Mean tended to decrease significantly between 1999 and 2007, although the change was not significant for Obs_MTE. Changes in air temperature and shortwave radiation played key roles in the long-term variation in ET over the humid area of China, but precipitation mainly controlled the long-term variation in ET in arid and semi-arid areas of China.

Plants regeneration from protoplast and their genetic variation in foxtail millet

Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann’t be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M1,M2 and M3 media successively and altering these media compo-sitions.The loosened calli can be selected from the regulation and used for protoplast isolationsuccessfully.Rate of protoplast division in KM8P medium was 12.3—33.5%.Calli derivedthrough protoplast division are loose and cann’t be used directly for plan regeneration because ofits soft physical structure.When they were subcultured in N6—1,N6—2,N6—3 and N6—4 media,in which the media compositions were changed,the compact calli were obtained and 129 plantletswere regenerated from them.101 plants,which grew to maturity after transplanting the plantletsinto field,exhibited sterility in some degree.Most of the subsequent lines derived from the regen-erated plants were sterile and only two lines could get normal reproduction.

Effects of input method and display mode of situation map on early warning aircraft reconnaissance task performance with different information complexities

Early Warning Aircraft(EWA)are the main force for air detection and its Human-Machine Interface(HMI)should be designed to support task efficiency and safety.With the appli-cation of advanced input method and interface design in EWA,little is known about their actual usability in terms of human factors and ergonomics.The aim of this study was to investigate the effects of the input method and display mode of the situation map on EWA reconnaissance task performance with different information complexities.Eighteen participants attended a three-factor within-subject design experiment with input method(touch screen and mouse),display mode of the situation map(color and grayscale),and information complexity(high and low)as the inde-pendent variables.Participant behavior performance,subjective workload,heart rate/heart rate variability,and eye movements were recorded as the dependent variables.The results suggest that a touch screen requires greater task completion time and has greater physical demands than mouse operation;however,it also facilitates information processing by reducing the average fixation time.Color mode significantly decreases saccade counts compared to grayscale mode and is considered more appropriate for target search tasks as it induces less visual search load.High information complexity produces significant negative effects on behavior performance and subjective workload.It also has significant interaction effects with input method on fixation and saccade counts.The findings have implications in the optimization design of Human–Machine Interface for EWA task systems.

Quantitative identification and the evolution characteristics of production–living–ecological space in the mountainous area:From the perspective of multifunctional land

Developed here is an integrated framework for identifying production–living–ecological space(PLES)quantitatively at grid scale from the perspective of multifunction land use,and 25 compound space types are classified to highlight the multiple functions of PLES.As a typical mountainous city in northern Hebei province,Zhangjiakou is used as a case study,and the results show that more than 80%of the land space in Zhangjiakou has remarkable triple functionality.The living-dominated space and the production-dominated space are distributed mainly in the valleys of the Yanghe,Sanggan,and Huliu rivers and have obvious spatial consistency,while the ecological-dominated space is concentrated mostly at the eastern Yanshan Mountains and southern Taihang Mountains and complements the other two types of space.The former two are spatially fragmented,while the latter has been expanding to the periphery over time.From 1990 to 2015,the ecological-dominated space has increased the most by 1555.02 km^(2),while the living-dominated space has increased the least by 816.79 km^(2).The types of PLES are more diverse in the medium and low mountains and the areas with gentle slope,and the influencing factors include natural ecological environment,socioeconomic development,human consumption demand,and institutional policies.Therefore,these findings can mitigate conflicts among PLES in mountainous and similar areas,and promote the balanced development of land space.

On the Enigma of Nb-Ta and Zr-Hf Fractionation——A Critical Review

Elemental ratios Zr/Hf and Nb/Ta are expected to be constant and of chondritic value （-36.30 and -17.57, respectively） in mantle and mantle-derived rocks. Studies in recent years have shown, however, that these two ratios do vary in some of these rocks. For example, MORB-like seamount lavas from flanks of the East Pacific Rise （EPR） show a correlated Zr/Hf （-25-50） and Nb/Ta （-9-18） variation. These two ratios are also correlated with ratios of more incompatible over less incompatible elements （e.g., La/Sm, Rb/Cs, Th/U, Nb/U, Sm/Yb） and with radiogenic isotope ratios （e.g., 87 Sr/86Sr, 143Nd/144Nd）. Furthermore, abyssal peridotites, which are melting residues for MORB, also show a huge correlated variation between Zr/Hf （-2.5-335） and Nb/Ta （-1-170）. All these observations plus a correlated variation between Zr/Hf （-22-48） and Nb/Ta （-10-23） in lunar rocks are consistent with the Zr-Hf and Nb-Ta fractionation being of magmatic origin. This contrasts with the common view that geochemical processes cannot readily fractionate them. As charges and ionic radii are the principal factors in the general theory of elemental fractionation, this theory cannot explain the fractionation of these two element pairs with the same charges （i.e., 5＋ for Nb and Ta, and 4＋ for Zr and Hf） and essentially the same ionic size （i.e., RNb/RTa=1.000, Rzr/RHf=1.006 to -1.026 for coordination numbers of 6, 7, 8 and 12）. We explore the possibilities of other factors and processes （e.g., mass-dependent fractionation during magmatism） that may cause the observed Nb-Ta and Zr-Hf fractionation. We emphasize that understanding the correlated Nb-Ta and Zr-Hf fractionation ＂known＂ to take place during magmatism is fundamental for improved understanding of elemental fractionations through other earth processes in various tectonic environments, including the origin and evolution of continental crust, which has a characteristic subchondritic Nb/Ta value of -11-12.