Mission description and in-flight operations of ERBE instruments on ERBS, NOAA 9, and NOAA 10 spacecraft

Instruments of the Earth Radiation Budget Experiment (ERBE) are operating on three different Earth-orbiting spacecraft. The Earth Radiation Budget Satellite (ERBS) is operated by NASA, and NOAA 9 and NOAA 10 weather satellites are operated by the National Oceanic and Atmospheric Administration (NOAA). This paper is the second in a series that describes the ERBE mission, and data processing and validation procedures. This paper describes the spacecraft and instrument operations for the second full year of in-orbit operations, which extend from February 1986 through January 1987. Validation and archival of radiation measurements made by ERBE instruments during this second year of operation were completed in July 1991. This period includes the only time, November 1986 through January 1987, during which all ERBE instruments aboard the ERBE, NOAA 9, and NOAA 10 spacecraft were simultaneously operational. This paper covers normal and special operations of the spacecraft and instruments, operational anomalies, and the responses of the instruments to in-orbit and seasonal variations in the solar environment

Magnetic phase diagram of the frustrated S=1/2 chain magnet LiCu_2O_2

We present the results of the magnetization and dielectric constant measurements on untwinned single crystal samples of the frustrated S=1/2 chain cuprate LiCu_2O_2. Novel magnetic phase transitions were observed. A spin flop transition of the spiral spin plane was observed for the field orientations H||a,b. The second magnetic transition was observed at H~15 T for all three principal field directions. This high field magnetic phase is discussed as a collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic chain system

Recommendations for reporting ion mobility Mass Spectrometry measurements

Here we present a guide to ion mobility mass spectrometry experiments, which covers both linear and nonlinear methods: what is measured, how the measurements are done, and how to report the results, including the uncertainties of mobility and collision cross section values. The guide aims to clarify some possibly confusing concepts, and the reporting recommendations should help researchers, authors and reviewers to contribute comprehensive reports, so that the ion mobility data can be reused more confidently. Starting from the concept of the definition of the measurand, we emphasize that (i) mobility values (K0) depend intrinsically on ion structure, the nature of the bath gas, temperature, and E/N; (ii) ion mobility does not measure molecular surfaces directly, but collision cross section (CCS) values are derived from mobility values using a physical model; (iii) methods relying on calibration are empirical (and thus may provide method‐dependent results) only if the gas nature, temperature or E/N cannot match those of the primary method. Our analysis highlights the urgency of a community effort toward establishing primary standards and reference materials for ion mobility, and provides recommendations to do so. © 2019 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc

Three-dimensional mapping reveals scale-dependent dynamics in biogenic reef habitat structure

Habitat structure influences a broad range of ecological interactions and ecosystem functions across biomes. To understand and effectively manage dynamic ecosystems, we need detailed information about habitat properties and how they vary across spatial and temporal scales. Measuring and monitoring variation in three-dimensional (3D) habitat structure has traditionally been challenging, despite recognition of its importance to ecological processes. Modern 3D mapping technologies present opportunities to characterize spatial and temporal variation in habitat structure at a range of ecologically relevant scales. Biogenic reefs are structurally complex and dynamic habitats, in which structure has a pivotal influence on ecosystem biodiversity, function and resilience. For the first time, we characterized spatial and temporal dynamics in the 3D structure of intertidal Sabellaria alveolata biogenic reef across scales. We used drone-derived structure-from-motion photogrammetry and terrestrial laser scanning to characterize reef structural variation at mm-to-cm resolutions at a habitat scale (~35 000 m2) over 1 year, and at a plot scale (2500 m2) over 5 years (2014–2019, 6-month intervals). We found that most of the variation in reef emergence above the substrate, accretion rate and erosion rate was explained by a combination of systematic trends with shore height and positive spatial autocorrelation up to the scale of colonies (1.5 m) or small patches (up to 4 m). We identified previously undocumented temporal patterns in intertidal S. alveolata reef accretion and erosion, specifically groups of rapidly accreting, short-lived colonies and slow-accreting, long-lived colonies. We showed that these highly dynamic colony-scale structural changes compensate for each other, resulting in seemingly stable reef habitat structure over larger spatial and temporal scales. These patterns could only be detected with the use of modern 3D mapping technologies, demonstrating their potential to enhance our understanding of ecosystem dynamics across scales

Deployable-erectable trade study for space station truss structures

The results of a trade study on truss structures for constructing the space station are presented. Although this study was conducted for the reference gravity gradient space station, the results are generally applicable to other configurations. The four truss approaches for constructing the space station considered in this paper were the 9 foot single fold deployable, the 15 foot erectable, the 10 foot double fold tetrahedral, and the 15 foot PACTRUSS. The primary rational for considering a 9 foot single-fold deployable truss (9 foot is the largest uncollapsed cross-section that will fit in the Shuttle cargo bay) is that of ease of initial on-orbit construction and preintegration of utility lines and subsystems. The primary rational for considering the 15 foot erectable truss is that the truss bay size will accommodate Shuttle size payloads and growth of the initial station in any dimension is a simple extension of the initial construction process. The primary rational for considering the double-fold 10 foot tetrahedral truss is that a relatively large amount of truss structure can be deployed from a single Shuttle flight to provide a large number of nodal attachments which present a pegboard for attaching a wide variety of payloads. The 15 foot double-fold PACTRUSS was developed to incorporate the best features of the erectable truss and the tetrahedral truss

The Threat of Multiâ Year Drought in Western Amazonia

Recent â onceâ inâ aâ centuryâ Amazonian droughts highlight the impacts of drought and climate change on this region’s vegetation, carbon storage, water cycling, biodiversity, land use, and economy. The latest climate model simulations suggest this region will experience worsening future drought. However, the instrumental record is too short to quantify the range of background drought variability, or to evaluate extended drought risk in climate models. To overcome these limitations, we generated a new, highly resolved lake record of hydroclimatic variability within the western Amazon Basin. We find that Amazonia has regularly experienced multiâ year droughts over the last millennium. Our results indicate that current climate model simulations likely underestimate the background risk of multiâ year Amazonian drought. These findings illustrate that the future sustainability of the Amazonian forest and its many services may require management strategies that consider the likelihood of multiâ year droughts superimposed on a continued warming trend.Plain Language SummaryThe Amazon basin recently experienced multiple â onceâ inâ aâ centuryâ droughts that impacted the region’s water cycle, economy, vegetation, and carbon storage. However, the instrumental record in this region tends to be too short to determine if these droughts are abnormal in a longâ term context. Paleoclimate data can extend drought records that help water and land managers plan for these events in the face of climate change. To provide additional information about preâ instrumental drought, here we present results from a new paleoclimate lake record based on sediments we recovered from Lake Limón in the Peruvian Amazon. We find that concentrations of elements in the Lake Limón sediment cores are likely recording past changes in rainfall variability. We use this elemental variability to generate a new, millennialâ length record of drought for the western Amazon. We show that this region has experienced multiâ year droughts at least twice a century over the last â ¼1,400 years. The frequency and severity of these paleoclimateâ inferred droughts may exceed most climate model and instrumentalâ era drought risk estimates. Our findings illustrate that the future sustainability of the Amazonian forest and its many ecosystem services may require management strategies that consider the likelihood of multiâ year droughts in addition to continued warming.Key PointsWe present results from a highâ resolution paleoclimate record of hydroclimatic variability in western AmazoniaOur paleoclimate record suggests western Amazonia has regularly experienced multiâ year drought over the last millenniumEarth system model simulations may underestimate the background risk of multiâ year western Amazonian droughtPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146272/1/wrcr23386_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146272/2/wrcr23386.pd

Excavations at the Early Caddo Period Mound Pond Site (41HS12) in Harrison County, Texas

This publication summarizes major archaeological findings from the July 1977 excavations at the Mound Pond site (41HS12), in the Pineywoods of Harrison County, Texas. The site lies on the south, or right, bank of Big Cypress Creek in the upper reaches of Caddo Lake, approximately 4 km north of the village of Uncertain. The Mound Pond Site was recorded by Dr. E. Mott Davis (The University of Texas at Austin) in the 1950s, during the time that he was conducting investigations at nearby Lake O’ the Pines Reservoir. Early in 1977, Forrest Murphey, of Marshall, Texas, approached Glenn Goode about assisting in a test excavation of the large mound at the site. Mr. Murphey (now deceased) had been informed that the landowners intended to build a house on the site, and that the mound would be leveled to make a flat surface. Forrest was a knowledgeable avocational archaeologist of the region, having worked for several years with Dr. Clarence H. Webb and others at the Resch site on Potters Creek south of Marshall, Texas. In preparation for this undertaking, Goode conducted a file and library search at the Texas Archeological Research Laboratory (TARL) at the University of Texas at Austin, and discussed with Dr. Dee Ann Story (director of TARL) the feasibility of attempting such an effort. It was agreed that given the circumstances of impending destruction, an attempt to learn as much as possible in the three weeks available should be made. With Murphey and Goode being the only individuals committed to the entire project, and with no money to hire a crew, they turned to both the avocational and professional communities for assistance. East Texas residents David C. (Dave) Brown of Texarkana Junior College, and Rodney Still, of Kilgore, devoted significant time and expertise to the project. Dave had considerable archaeological experience in East Texas, having worked on several projects for Southern Methodist University in the 1960s. In 1974, Rodney had worked with Goode and the Texas Highway Department at the Marshall Powder Mill excavations, and he was keenly interested in all aspects of Caddo and moundbuilder archaeology