The SORCE Science Data System

The SORCE Science Data System produces total solar irradiance (TSI) and spectral solar irradiance (SSI) data products on a daily basis, which are formulated using measurements from the four primary instruments onboard the SORCE spacecraft. The Science Data System utilizes raw spacecraft and instrument telemetry, calibration data, and other ancillary information to produce and distribute a variety of data products that have been corrected for all known instrumental and operational effects. SORCE benefits from a highly optimized object-oriented data processing system in which all data are stored in a commercial relational database system, and the software itself determines the versions of data products at run-time. This unique capability facilitates optimized data storage and CPU utilization during reprocessing activities by requiring only new data versions to be generated and stored. This paper provides an overview of the SORCE data processing system, details its design, implementation, and operation, and provides details on how to access SORCE science data products.     

A nonparametric view of generalized covariances for kriging

Fitting trend and error covariance structure iteratively leads to bias in the estimated error variogram. Use of generalized increments overcomes this bias. Certain generalized increments yield difference equations in the variogram which permit graphical checking of the model. These equations extend to the case where errors are intrinsic random functions of order k, k=1, 2, ..., and an unbiased nonparametric graphical approach for investigating the generalized covariance function is developed. Hence, parametric models for the generalized covariance produced by BLUEPACK-3D or other methods may be assessed. Methods are illustrated on a set of coal ash data and a set of soil pH data.     

Pleistocene aeolianites at Cape Spencer,South Australia; record of a vanished inner neritic cool‐water carbonate factory

Aeolianites are integral components of many modern and ancient carbonate depositional systems. Southern Australia contains some of the most impressive and extensive late Cenozoic aeolianites in the modern world. Pleistocene aeolianites on Yorke Peninsula are sculpted into imposing seacliffs up to 60 m high and comprise two distinct imposing complexes of the Late Pleistocene Bridgewater Formation. The lower aeolianite complex, which forms the bulk of the cliffs, is a series of stacked palaeodunes and intervening palaeosols. The diagenetic low Mg‐calcite sediment particles are mostly bivalves, echinoids, bryozoans and small benthic foraminifera. This association is similar to sediments forming offshore today on the adjacent shelf in a warm‐temperate ocean. By contrast, the upper aeolianite complex is a series of mineralogically metastable biofragmental carbonates in a succession of stacked lenticular palaeodunes with impressive interbedded calcretes and palaeosols. Bivalves, geniculate coralline algae and benthic foraminifera, together with sparse peloids and ooids, dominate sediment grains. Fragments of large benthic foraminifera including Marginopora vertebralis, a photosymbiont‐bearing protist, are particularly conspicuous. Palaeocean temperatures are interpreted as having been sub‐tropical, somewhat warmer than offshore carbonate factories in the region today. The older aeolianite complex is tentatively correlated with Marine Isotope Stage 11, whereas the upper complex is equivalent to Marine Isotope Stage 5e. Marine Isotope Stage 5e deposits exposed elsewhere in southern Australia (Glanville Formation) are distinctive with a subtropical biota, including Marginopora vertebralis. Thus, in this example, palaeodune sediment faithfully records the nature of the adjacent inner neritic carbonate factory. By inference, aeolianites are potential repositories of information about the nature of long‐vanished marine systems that have been removed due to erosion, tectonic obliteration or are inaccessible in the subsurface. Such information includes not only the nature of marine environments themselves but also palaeoceanography.     

Impact of an 0.2 km3 Rock Avalanche on Lake Eibsee (Bavarian Alps,Germany) – Part I: Reconstruction of the paleolake and Effects of the Impact

Rock avalanches destroy and reshape landscapes in only a few minutes and are among the most hazardous processes on Earth. The surface morphology of rock avalanche deposits and the interaction with the underlying material are crucial for runout properties and reach. Water within the travel path is displaced, producing large impact waves and reducing friction, leading to long runouts. We hypothesize that the 0.2 km³ Holocene Eibsee rock avalanche from Mount Zugspitze in the Bavarian Alps overran and destroyed Paleolake Eibsee and left a unique sedimentological legacy of processes active during the landslide. We captured 9.5 km of electrical resistivity tomography (ERT) profiles across the rock avalanche deposits, with up to 120 m penetration depth and more than 34 000 datum points. The ERT profiles reveal up to ~50 m thick landslide debris, locally covering up to ~30 m of rock debris with entrained fine-grained sediments on top of isolated remnants of decametre-wide paleolake sediments. The ERT profiles allow us to infer processes involved in the interaction of the rock avalanche with bedrock, lake sediments, and morainal sediments, including shearing, bulging, and bulldozing. Complementary data from drilling, a gravel pit exposure, laboratory tests, and geomorphic features were used for ERT calibration. Sediments overrun by the rock avalanche show water-escape structures. Based on all of these datasets, we reconstructed both position and size of the paleolake prior to the catastrophic event. Our reconstruction of the event contributes to process an understanding of the rock avalanche and future modelling and hazard assessment. Here we show how integrated geomorphic, geophysical, and sedimentological approaches can provide detailed insights into the impact of a rock avalanche on a lake. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd     

Ensemble properties of comets in the Sloan Digital Sky Survey

We present the ensemble properties of 31 comets (27 resolved and 4 unresolved) observed by the Sloan Digital Sky Survey (SDSS). This sample of comets represents about 1 comet per 10 million SDSS photometric objects. Five-band (u, g, r, i, z) photometry is used to determine the comets’ colors, sizes, surface brightness profiles, and rates of dust production in terms of the Afρ formalism. We find that the cumulative luminosity function for the Jupiter Family Comets in our sample is well fit by a power law of the form N(<H) ∝ 10^{(0.49±0.05)H} for H < 18, with evidence of a much shallower fit N(<H) ∝ 10^{(0.19±0.03)H} for the faint (14.5 < H < 18) comets. The resolved comets show an extremely narrow distribution of colors (0.57 ± 0.05 in g ? r for example), which are statistically indistinguishable from that of the Jupiter Trojans. Further, there is no evidence of correlation between color and physical, dynamical, or observational parameters for the observed comets.     

云南哈播斑岩铜(-钼-金)矿床流体包裹体研究

哈播斑岩Cu-(Mo-Au)矿床产于哀牢山富碱斑岩带的南段,形成于青藏高原后碰撞阶段构造转换环境,属于陆-陆碰撞型斑岩矿床.根据脉体的交切关系,确定哈播矿床各种脉的演化序列为早期石英脉→石英-黄铜矿脉→石英辉钼矿脉.脉中流体包裹体的岩相学、显微测温和激光拉曼光谱分析等研究结果显示,各期脉中均有富气相包裹体、富液相包裹体和含子矿物多相包裹体,各种包裹体的气相均含有CO2、SO2、H2O等气体.各期脉中多种包裹体并存并具有相似的均一温度范围,富液相包裹体均一温度149～427℃,盐度ω(NaCleq)6.0％～15.0％;富气相包裹体均一温度205～405℃,盐度ω(NaCleq) 3.4％～19.0％;含子矿物多相包裹体均一温度305～516℃,盐度w(NaCleq) 33.5％～61.0％.哈播矿床的初始成矿流体由稳定共存、不混溶的低盐度流体和高盐度流体组成,高盐度流体是哈播矿床成矿元素迁移的主要载体.成矿流体在400℃左右发生“二次沸腾”、分相,温度下降和挥发分持续逃逸可能是Cu-Au成矿的诱因.Mo元素在成矿流体多次沸腾、分相过程中,持续优先分配进入高盐度流体中而逐步富集;温度下降,使含钼硫化物在流体中溶解度降低、沉淀,形成石英-辉钼矿±黄铜矿脉.     

Aeolianites reveal Pleistocene marine history of Bermuda

Bermuda is a reef atoll along the northern edge of Caribbean coral province. Although investigated by seismic and some shallow drilling, the Pleistocene marine depositional geohistory is poorly constrained. Islands along the southern rim are built by tropical calcareous aeolianites that range in age from Holocene to early Pleistocene (ca 880 kyr). These dunes are composed of particles that were derived from adjacent Pleistocene marine environments at the time of formation. Thus, the aeolianites should contain a record of marine deposition through the Early to Late Pleistocene. Carbonate grains from all aeolian deposits can, via Ward cluster analysis, be separated into two distinct groups: (i) a Halimeda‐rich group; and (ii) a crustose coralline‐rich group. Distribution of these two groups is interpreted to broadly reflect low‐energy (lagoonal) and high‐energy marginal reef (coralline algae and cup‐reef) environments, respectively. Unlike the beach sources, coral particles are perplexingly absent in the aeolianites. This conundrum is interpreted to partly reflect the domal nature of Bermudan corals, which are not incorporated into aeolian deposits due to their relatively large size. Aeolianites from Marine Isotope Stages 7, 9 and 11 record sediments produced in adjacent shallow marine settings that were similar to those present today. The spatially consistent sediment trends are not, however, present in aeolianites from Marine Isotope Stage 5E, where the aeolian bioclastic components are uniformly rich in Halimeda along both southern and northern shores. Such a distribution, where coralline‐rich sediments would be expected, suggests an extrinsic oceanographic control, interpreted herein to be elevated seawater temperature brought in by the Gulf Stream. This interpretation is consistent with palaeozoological studies of Bermuda, as well as North America, the Mediterranean, Japan and Western Australia.     

Meteorological analysis of the tornado in Ciudad Acuña,Coahuila State,Mexico, on May 25, 2015

Extreme meteorological conditions favor the development of severe storms and tornadoes that may have largely impacts on the population despite its relatively short life. Tornadic severe storms have been documented around the World. In Mexico (MEX), the study of the occurrence of tornadoes and severe storms is relatively new. In this research, we have selected an event of severe tornadic storm in Ciudad Acuña, Mexico. The storm was driven by a frontal system moving southward from USA converging with a warmer moist air flux from the Gulf of Mexico. The tornado strikes on the Northeast of Mexico, in Coahuila State, on May 25, 2015. Imagery of infrared channel from GOES 13 satellite and the presence of a hook echo in radar data of May 25, 2015, indicate a supercell structure. The maximum values of radial velocity were about ?20 and 15 m s^?1. In this study, the WRF model was used in order to simulate the mesoscale meteorological conditions of the tornado. Model simulations capture atmospheric features observed in Doppler radar. The simulated storm-relative helicity values were between 400 and 500 m² s^?2. The simulated convective available potential energy values were of 3000 J kg^?1. These values were higher than values for convective storms, located over the region of Ciudad Acuña in Mexico and Del Rio in USA. The supercell was a result of high humidity and temperature gradients, conditioned by frontal activity and moisture flux intensifications from the Gulf of Mexico.