摘要：The virtual globe is the default visualization for Digital earth applications,but it can only show one half of the *** article introduces user-adjustable,on-the-fly projection of georeferenced raster images for web mapping and web GIS *** technique allows users to center a map on arbitrary locations,while still seeing the entire earth *** web mapping libraries can apply map projection transformations to vector data in the browser,but they do not currently support the projection of raster images at interactive frame *** use the cross-platform WebGL(Web Graphics Library)graphics pipeline for hardware-accelerated projection of raster data in web *** algorithmic techniques–inverse per-fragment projection,and combined forward per-triangle and inverse per-fragment projection–for georeferenced raster imagery are *** resulting raster maps combine the ease of use and flexibility of interactive virtual globes with the ability to show the entire *** adjustable projection of raster imagery allows users to observe global phenomena that are difficult to visualize on virtual globes or traditional maps with static projections.

摘要：A streamfunction projection method called gravest empirical mode(GEM) is applied to the hydrographic section at 137°E to filter out eddy noises in the western North Pacific and derive quantitative ensemble-average water mass properties in the North Equatorial Current region. The GEM fields capture more than 80% of total property variances in the thermocline layer. The core layer structures of key water masses, including the North Pacific Tropical Water(NPTW) and the North Pacific Intermediate Water(NPIW), are examined with a definition of water mass boundary based on property gradient. It shows that a tongue of maximal root-mean-square(RMS) residual exists in the upper half of NPIW for all water properties. These subsurface RMS tongues appear to be close to sharp property gradients. It is the first time a GEM diagnosis is applied to nutrient data, which reveals a drastic difference of N/P reaction rate ratio above and below the maximal-nutrient core at 1250 m. Additionally, a GEM velocity reconstruction successfully produces the North Equatorial Undercurrent(NEUC), demonstrating the stable thermal-wind nature of this newly-discovered current.

摘要：A study of coccolith assemblages from a box core from the central South Yellow Sea（SYS） was performed revealing fluctuations on their relative abundance（%） that can be related to climatic and hydrographic changes over the last 230 years（1780–2011）. Total coccolith abundances ranged from 7.0 to 55.1×10^6 coccoliths·g^-1sediment. Although the abundance of different species varied widely throughout the core, seven taxa dominated the assemblage. Among these species, Gephyrocapsa oceanica was the most dominant species, and it showed an average percentage of 50.1%. The pattern of G. oceanica（eutrophic species） was opposite to that of the combined percentage of Braarudosphaera bigelowii and Umbilicosphaera sibogae（both oligotrophic species）, indicating that in the Yellow Sea（YS）, the distribution pattern of G. oceanica might be characteristic of nutrient *** patterns between G. oceanica and the Siberian High were observed on an inter-decadal time scale,indicating that the East Asian Winter Monsoon（EAWM） may be an important driver of ecological changes in the YS. When the EAWM prevails, both the Yellow Sea Coastal Current（YSCC） and Yellow Sea Warm Current（YSWC）strengthen, and the increasing nutrient availability and warmer water brought by the strengthened YSWC favor eutrophic and warm-water coccolithophore species, such as G. oceanica. This likely mechanism demonstrates that coccolith assemblages can be used as benign and reliable proxy for climate change and surface oceanography.

摘要：Based on coral proxies we reconstructed the western Pacific warm pool sea surface temperature (SST) since 1644 AD. High-frequency reconstructions are based on eight high-pass filtered coral series and raw reconstructions are derived from eight unfiltered coral series, respectively. Validation and comparison with other SST/temperature series show that the reconstructed warm pool SST is highly reliable. The leading periods of warm pool SST are ～2.1, ～2.3, ～2.9, ～3.6, ～3.8, and 80.7-year during the last ～360 years. The warm pool SST exhibits some obvious long-term trends: an upward trend of 0.04°C per century for the period of 1644–1825, while a decreasing trend of 0.24°C per century for the period of 1826–1885, and then a remarkable warming trend of 0.28°C per century taking place between 1886 and 2006. Especially, the SST shows the strongest trend of 0.67°C increase per century during the last 50 years, a warming unprecedented since 1644 AD. On interannual timescale, the connections between ENSO and the warm pool SST are robust during the reconstruction period. There are significant correlations between the warm pool SST and summer precipitation of the Yellow River basin and Huaihe River basin; the correlation coefficients are ?0.44 in reconstruction period (1880–1949 AD) and ?0.46 in instrumental period (1950–2005 AD) respectively. This relationship is also found between flood-drought index and the warm pool SST during the past 360 years, and their correlation coefficients are ?0.20 in reconstruction period and ?0.46 in instrumental period respectively, significant at the 0.01 level. On interdecadal timescale, this connection is more robust, and the correlation coefficient of the low-pass filtered components is ?0.42 during the whole period (1644–2000 AD). When the warm pool is warmer than normal, the precipitation is usually below the normal in the Yellow River and Huaihe River basin. On the contrary, when the warm pool is colder than the normal, there may be more

摘要：Sedimentary pigments are useful proxy indicators of phytoplankton biomass, community structure, primary productivity and human influence in lacustrine and oceanic ecosystems. Pigments are relatively labile due to their complex chemical structures, which makes the extraction and analysis of sedimentary pigments challenging. In addition, it is important to select appropriate methods to study sedimentary pigments in regions which lack previous investigations. In this study, we adopted the L9（34） orthogonal design to develop methods of extraction and HPLC （high performance liquid chromatography） analysis of sedimentary pigments at two lakes on the Tibetan Plateau： meromictic lake-Dagze Co and dimictic lake-Jiang Co. The orthogonal design comprises 9 combinations of various parameters for extraction and HPLC analysis. The results show that the type and volume of solvent are the most important factors for pigment extraction, and the mobile phase and column selection are the most important for HPLC analysis. For the study sites, we found that the best methods to extract sedimentary pigments are as follows： the use of a mixture of acetone：methanol：water （80： 15：5, v：v：v） as the extraction solvent; sol- vent/sample ratio of 10 mL/g; sonication for 30 s and standing extraction for 6 h. The best methods for HPLC analysis are as follows： Zorbax Eclipse plus C8 column with mobile phase A, methanol：acetonitrile：0.25 M aqueous pyridine （50： 25：25, v ： v ： v） and mobile phase B, methanol： acetonitrile： acetone （20： 60： 20, v： v： v）; pH of mobile phase A adjusted to 6 with acetic acid; and HPLC column temperature maintained at 40~C. The study provides an experimental basis for future investigations of past changes in primary productivity and the response of lake ecosystems to climate change and human activities on the Tibetan Plateau.

摘要：In order to enter effective parameters of rock mass in a numerical model,the relationships between mechanical parameters of rock and rock mass were obtained by an inversion method and an orthogonal test,given our measurements of the maximum heights of two failure zones in the Longdong coal mine. Using the maximum heights of the caving zone and the water-conducting fractured zone as test indices the modulus of elasticity,the Poisson ratio,cohesion and tension strength as test factors and different values of reduction enhancement factors as test levels,an orthogonal test was designed to obtain an optimum simulation *** the analysis of different values of reduction enhancement factors which affect the test indices,an optimum factor combination for modification of parameters could be *** using modified parameters in our numerical simulation,the maximum heights of the caving zone and the water-conducting fractured zone in the extensive Xiyi area were determined as 15.06 m and 36.92 *** values were almost the same as those obtained by similar material simulation（8.5 m and 37.0 m）and empirical prediction（8.4 m and 34.4 m）.These results indicate that the modification of parameters is a rational method.

摘要：This paper extends the dimension-reduced projection four-dimensional variational assimilation method(DRP-4DVar) by adding a nonlinear correction process,thereby forming the DRP-4DVar with a nonlinear correction, which shall hereafter be referred to as the NC-DRP-4DVar. A preliminary test is conducted using the Lorenz-96 model in one single-window experiment and several multiple-window experiments. The results of the single-window experiment show that compared with the adjoint-based traditional 4DVar, the final convergence of the cost function for the NC-DRP-4DVar is almost the same as that using the traditional 4DVar, but with much less computation. Furthermore, the 30-window assimilation experiments demonstrate that the NC-DRP-4DVar can alleviate the linearity approximation error and reduce the root mean square error significantly.

摘要：Conditional nonlinear optimal perturbation(CNOP) is an extension of the linear singular vector technique in the nonlinear *** represents the initial perturbation that is subjected to a given physical constraint,and results in the largest nonlinear evolution at the prediction ***-type errors play an important role in the predictability of weather and ***,when calculating CNOP in a complicated numerical model,we need the gradient of the objective function with respect to the initial perturbations to provide the descent direction for searching the phase *** adjoint technique is widely used to calculate the gradient of the objective ***,it is difficult and cumbersome to construct the adjoint model of a complicated numerical model,which imposes a limitation on the application of *** on previous research,this study proposes a new ensemble projection algorithm based on singular vector decomposition(SVD).The new algorithm avoids the localization procedure of previous ensemble projection algorithms,and overcomes the uncertainty caused by choosing the localization radius *** new algorithm is applied to calculate the CNOP in an intermediate forecasting *** results show that the CNOP obtained by the new ensemble-based algorithm can effectively approximate that calculated by the adjoint algorithm,and retains the general spatial characteristics of the ***,the new SVD-based ensemble projection algorithm proposed in this study is an effective method of approximating the CNOP.

摘要：Observations show that Arctic sea ice has been dramatically declined,and the surface temperature in Arctic region is dramatically increasing since *** the end of 2020,the summer sea ice extent had been decreased by more than 50%comparing with the area in the late *** increasing rate of surface atmospheric and oceanic temperature was about 2-3 times faster than that of the global average(Meredith et al.,2019).Arctic is experiencing rapid change.

摘要：Many rock avalanches were triggered by the Wenchuan earthquake on May 12, 2008 in southwest China. Protection galleries covered with a single soil layer are usually used to protect against rockfall. Since one-layer protection galleries do not have sufficient buffer capacity, a two-layered absorbing system has been designed. This study aims to find whether an expanded poly-styrol （EPS） cushion, which is used in the soil-covered protection galleries for shock absorption, could be positioned under dynamic loadings. The dynamic impacts of the two-layered absorbing system under the conditions of rock avalanches are numerically simulated through a 2D discrete dement method. By selecting reasonable parameters, a series of numerical experiments were conducted to find the best combination for the two- layered absorbing system. The values of the EPS layer area as a percentage of the total area were set as 0% （Sl）, 22~ （S2）, and 70% （$3）. 22~ of the area of the EPS layer was found to be a reasonable value, and experiments were conducted to find the best position of the EPS layer in the two-layered absorbing system. The numerical results yield useful conclusions regarding the interaction between the impacting avalanches and the two-layered absorbing system. The soil layer can absorb the shock energy effectively and S2 （0.4-m thick EPS cushion covered with soil layer） is the most efficient combination, which can reduce the impact force, compared with the other combinations.