Explore the vast range of titles available.

In a warming climate, net mass loss from perennial snow and ice (PSI) contributes a temporary source of unsustainable streamflow. However, the role of topography and wind in mediating the streamflow patterns of deglaciating watersheds is unknown. We compare lidar surveys of seasonal snow and PSI elevation change for five adjacent watersheds in the Wind River Range, Wyoming (WRR). Between 2019 and 2023, net mass loss from PSI is equivalent to ∼ 10 %–36 % of August–September streamflow. Across 338 manually classified PSI features >0.01 km2, glaciers contribute 68 % of the total mass loss, perennial snowfields contribute 8 %, rock glaciers contribute 1 %, buried ice contributes 6 %, and the remaining 17 % derives from semi-annual snowfields and small snow patches. Surprisingly, watersheds with more area-normalized seasonal snow produce less late-summer streamflow (r=-0.60), but this correlation is positive (r=0.88) considering only deep snow storage (SWE > 2 m). Most deep snow (87 %) is associated with topography that is conducive to wind drift formation. Deep seasonal snow limits the mass loss contribution of PSI features in topographic refugia. We show that watersheds with favorable topography exhibit deeper seasonal snow, more abundant PSI features (and hence greater mass loss in a warming climate), and elevated late-summer streamflow. As a result of deep seasonal snow, watersheds with the most abundant PSI would still produce 45 %–78 % more late-summer streamflow than nearby watersheds in a counterfactual scenario with zero net mass loss. Similar interrelationships may be applicable to mountain environments globally.

The Moon Mineralogy Mapper (M3), a high‐resolution, high‐precision imaging spectrometer, flew on board India's Chandrayaan‐1 Mission from October 2008 through August 2009. This paper describes some of the spatial sampling aspects of the instrument, the planned mission, and the mission as flown. We also outline the content and context of the resulting Level 1B spatial products that form part of the M3 archive. While designed and planned to operate for 2 years in a 100 km lunar orbit, M3 was able to meet its lunar coverage requirements despite the shortened mission; an increase of the orbit altitude to 200 km; and several relevant problems with spacecraft attitude, timing, and ephemeris. The unexpected spacecraft issues required us to invent a novel two‐step approach for selenolocation. Leveraging newly available Lunar Reconnaissance Orbiter‐Lunar Orbiter Laser Altimeter (LOLA) topography and an improved spacecraft ephemeris, we have created a method that permits us to bootstrap spacecraft attitude estimates from the image data themselves. This process performs a nonlinear optimization to honor a set of data‐derived image‐to‐image tie points and image‐to‐LOLA control points. Error analysis of the final results suggests we have converged to a selenolocation result that has image‐to‐image root‐mean‐square (RMS) errors less than 200 m and image‐to‐LOLA RMS errors less than 450 m, despite using data‐derived spacecraft attitude results. The Level 1B products include the lunar coordinates resulting from this inversion process and 10 relevant observational geometry parameters that fully characterize the ray tracing geometry on a pixel‐by‐pixel basis. Key Points Moon Mineralogy Mapper spatial characteristics Selenodesy results for M3 mapping M3 Level 1B archive product description

Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts.

This paper briefly describes the methods available for collection, atmospheric and geometric correction, and processing of hyperspectral imagery. Discussion of data capture concentrates on logistics of integrating image acquisition with field data collection. Atmospheric correction is required to use the imagery with reference spectra from field and laboratory sensors; a variety of methods for atmospheric correction are described. Geometric correction is required for integration of the image data and derived products with other geographic information. A description of methods for single and multiple feature identification is provided. These all focus on the analysis of the spectral description of surface materials provided by hyperspectral imagery; methods for multiple feature identification take advantage of high spectral dimensionality of the imagery to identify sub-pixel components. A role for spatial analysis combined with spectral analysis in interpretation of environmental features is identified.

We examined the lunar swirls using data from the Moon Mineralogy Mapper (M3). The improved spectral and spatial resolution of M3 over previous spectral imaging data facilitates distinction of subtle spectral differences, and provides new information about the nature of these enigmatic features. We characterized spectral features of the swirls, interswirl regions (dark lanes), and surrounding terrain for each of three focus regions: Reiner Gamma, Gerasimovich, and Mare Ingenii. We used Principle Component Analysis to identify spectrally distinct surfaces at each focus region, and characterize the spectral features that distinguish them. We compared spectra from small, recent impact craters with the mature soils into which they penetrated to examine differences in maturation trends on‐ and off‐swirl. Fresh, on‐swirl crater spectra are higher albedo, exhibit a wider range in albedos and have well‐preserved mafic absorption features compared with fresh off‐swirl craters. Albedoand mafic absorptions are still evident in undisturbed, on‐swirl surface soils, suggesting the maturation process is retarded. The spectral continuum is more concave compared with off‐swirl spectra; a result of the limited spectral reddening being mostly constrained to wavelengths less than ∼1500 nm. Off‐swirl spectra show very little reddening or change in continuum shape across the entire M3 spectral range. Off‐swirl spectra are dark, have attenuated absorption features, and the narrow range in off‐swirl albedos suggests off‐swirl regions mature rapidly. Spectral parameter maps depicting the relative OH surface abundance for each of our three swirl focus regions were created using the depth of the hydroxyl absorption feature at 2.82 μm. For each of the studied regions, the 2.82 μm absorption feature is significantly weaker on‐swirl than off‐swirl, indicating the swirls are depleted in OH relative to their surroundings. The spectral characteristics of the swirls and adjacent terrains from all three focus regions support the hypothesis that the magnetic anomalies deflect solar wind ions away from the swirls and onto off‐swirl surfaces. Nanophase iron (npFe0) is largely responsible for the spectral characteristics we attribute to space weathering and maturation, and is created by vaporization/deposition by micrometeorite impacts and sputtering/reduction by solar wind ions. On the swirls, the decreased proton flux slows the spectral effects of space weathering (relative to nonswirl regions) by limiting the npFe0 production mechanism almost exclusively to micrometeoroid impact vaporization/deposition. Immediately adjacent to the swirls, maturation is accelerated by the increased flux of protons deflected from the swirls. Key Points The swirls are depleted in OH relative to their surroundings On‐swirl spectral maturation is retarded and is accelerated off‐swirl Our results suport deflection of solar wind ions by the magnetic anomalies

The Moon Mineralogy Mapper (M³) is a NASA-supported guest instrument on ISRO's remote sensing mission to Moon, Chandrayaan-1. The M³ is an imaging spectrometer that operates from the visible into the near-infrared (0.42–3.0 μm) where highly diagnostic mineral absorption bands occur. Over the course of the mission M³ will provide low resolution spectroscopic data for the entire lunar surface at 140 m/pixel (86 spectral channels) to be used as a base-map and high spectral resolution science data (80 m/pixel; 260 spectral channels) for 25–50% of the surface. The detailed mineral assessment of different lunar terrains provided by M³ is principal information needed for understanding the geologic evolution of the lunar crust and lays the foundation for focused future in-depth exploration of the Moon.

Lunar geochemical groups such as Mg suite, ferroan anorthosite, and alkali suite rocks are difficult to distinguish from orbit because they are defined by both modal mineralogy and elemental composition of their constituent minerals. While modal mineralogy can be modeled, only specific minerals or elements can be directly detected. At near‐infrared (NIR) wavelengths, pyroxenes are among the most spectrally distinctive minerals, and their absorption bands are sensitive to structure and composition. Pyroxenes thus provide important clues to distinguish these geochemical groups and to understand lunar crustal evolution. Using Moon Mineralogy Mapper data, we search for lithologies dominated by strong low‐calcium pyroxene (LCP) signatures. We compare the NIR absorptions of 20 LCPs to a suite of synthetic pyroxenes to determine which lunar pyroxenes appear magnesian enough to be candidate Mg suite norites. We detail three prominent regions of LCP (1) in South Pole–Aitken Basin (SPA), (2) south of Mare Frigoris, and (3) north of Mare Frigoris. The absorption band positions suggest that the LCPs north of Mare Frigoris and those in SPA are compositionally similar to one another and of ∼Mg50–75, implying that the mafic material excavated by the SPA impact was relatively iron‐rich. Modified Gaussian modeling results suggest that the Apollo basin may have tapped different composition material than is exposed in much of SPA. The LCPs located in the highlands south of Mare Frigoris exhibit absorption bands at short wavelengths consistent with Mg > ∼80. The coincidence of these Mg‐rich LCPs with the thorium measured by Lunar Prospector make them good candidates for KREEP‐related Mg suite pyroxenes. Key Points Global survey of exposures of lunar norites Compositional analysis of freshest exposed norites High‐Mg norites in Apollo Basin and around Mare Imbrium

The Moon Mineralogy Mapper (M3) provided the first global hyperspectral data of the lunar surface in 85 bands from 460 to 2980 nm. The Clementine mission provided the first global multispectral maps the lunar surface in 11 spectral bands across the ultraviolet‐visible (UV‐VIS) and near‐infrared (NIR). In an effort to understand how M3 improves our ability to analyze and interpret lunar data, we compare M3 spectra with those from Clementine's UV‐VIS and NIR cameras. The Clementine mission provided the first global multispectral maps the lunar surface in 11 spectral bands across the UV‐VIS and NIR. We have found that M3 reflectance values are lower across all wavelengths compared with albedos from both of Clementine's UV‐VIS and NIR cameras. M3 spectra show the Moon to be redder, that is, have a steeper continuum slope, than indicated by Clementine. The 1 μm absorption band depths may be comparable between the instruments, but Clementine data consistently exhibit shallower 2 μm band depths than M3. Absorption band minimums are difficult to compare due to the significantly different spectral resolutions. Key Points Comparing lunar surface spectral data Comparing performance of two lunar orbiter instruments Preparing community to use new lunar spectral data

When the private freight railroads desperately wanted out of the passenger rail business, Congress saw the need for a single national passenger rail service provider with a passion to improve passenger rail service that could operate an interconnected network of routes. Thus, Amtrak began operations in 1971 and then took ownership much of the Northeast Corridor in 1976. To the surprise of many, and despite chronic underfunding, they've trade a go of it. In 2011, Amtrak is celebrating 40 years as America's Railroad. Since 2000, Amtrak ridership is up by 36% and they have set annual ridership records in seven of the last eight fiscal years. This year they will exceed 30 million passengers for the first time ever. Over the years they have been the leader in regular passenger and high speed rail, and continue to be so today by providing their extensive knowledge and experience to state partners and commuter agencies throughout the country.