Radar climatology of Gauhati airport and its neighbourhood

Radar observations at Gauhati Airport for the period of51 months from March 1960 to October 1967 (excluding 1966) form the basis of this climatological study. Monthly and seasonal distribution of the precipitation echoes. With respect to their areal coverage hail been studied. The diurnal variation of the areal coverage by the precipitation echoes during the different periods of a day in a month has also been studied.

Resolving Io’s Volcanoes from a Mutual Event Observation at the Large Binocular Telescope

Unraveling the geological processes ongoing at Io’s numerous sites of active volcanism requires high spatial resolution to, for example, measure the areal coverage of lava flows or identify the presence of multiple emitting regions within a single volcanic center. In de Kleer et al. (2017) we described observations with the Large Binocular Telescope during an occultation of Io by Europa at ∼6:17 UT on 2015 March 8 and presented a map of the temperature distribution within Loki Patera derived from these data. Here we present emission maps of three other volcanic centers derived from the same observation: Pillan Patera, Kurdalagon Patera, and the vicinity of Ulgen Patera/PV59/N Lerna Regio. The emission is localized by the light curves and resolved into multiple distinct emitting regions in two of the cases. Both Pillan and Kurdalagon Paterae had undergone eruptions in the months prior to our observations, and the location and intensity of the emission are interpreted in the context of the temporal evolution of these eruptions observed from other facilities. The emission from Kurdalagon Patera is resolved into two distinct emitting regions separated by only a few degrees in latitude that were unresolved by Keck observations from the same month.

Coordinate binding of images for designing phototrangulation

The technology of the schemes development automation for areal coverage with aerial and space photography materials is proposed. Within its framework, a method for automatic coordinate referencing of images on the Earth’s ellipsoid surface with the subsequent determination of nomenclature sheets of topographic maps on a composite table was substantiated and implemented. The proposed method is based on the algorithms for calculating the azimuths and lengths of lines connecting the projections of the photographing points (inverse geodetic problem) and the coordinates of the images corner points’ projections (direct geodetic problem). The formulas for solving the geodetic tasks of the images coordinate referencing over long distances are obtained as a result of transforming and integrating the equations of geodetic lines described by the Claireau equation though F. Bessel’s method. It can be used when planning and performing aerial and space surveys, as well as to determine the cartographic base in order to select the starting points for photogrammetric condensation of the geodetic network. The technology is focused on the automation of phototriangulation technical design procedures and is good for linking images to the corresponding sections of electronic and digital maps.

Automatic image referencing in satellite surveying

The method of coordinate referencing of remote sensing materials in the process of satellite surveying is proposed in this paper. The method provides automatic determination of position of the survey routes and images in the routes on the surface of the Earth ellipsoid with their subsequent displaying on the nomenclature sheets of topographic maps on the composite table. The method provides for fully automatic development of a scheme of areal coverage with survey materials in the presence of data on the coordinates of photographing points obtained at the moments of exposure. The algorithm can be used to link images to the corresponding areas of electronic and digital maps.

Estimating Area Coverage and Volume of Hot Lava by Integrating Multiple Satellite Remote Sensing Techniques

<p>Monitoring the regions that are prone to natural hazards is essential in disaster management, since early warnings can be issued. Airborne and space-borne remote sensing techniques are cost-effective in accomplishing the task. Estimating the area and volume of erupted lava can help researchers understand the volcanic processes and impact on land use and land cover. In this study, we developed a new algorithm to estimate areal coverage and volume of exposed hot lava by integrating the space-borne Interferometric Synthetic Aperture Radar (InSAR), thermal infrared, and Normalized Vegetation Distribution Index (NDVI) techniques. We applied this algorithm to the eruption of the East Rift Zone (ERZ) of the Kilauea volcano took place between May and August 2018 and estimated the areal coverage and volume of lava erupted. We compared the results of InSAR to those derived from airborne Light Detection and Ranging (LiDAR), and found that although air-borne LiDAR provides data with higher resolution and accuracy, InSAR is almost as good as LiDAR in monitoring deformed areas and has larger spatial and temporal coverage.</p>

The River Corridor's Evolving Connectivity of Lotic and Lentic Waters

River corridors supply a substantial proportion of the fresh water for societal and ecological needs. Individual functions of flowing (lotic) streams and rivers and ponded (lentic) waterbodies such as lakes and reservoirs are well-studied, but their collective functions are not as well understood. Here we bring together nationally consistent river corridor datasets to characterize the contributions of lotic and lentic features and to estimate changes over the past centuries. High-resolution datasets describing waterbodies across 10 million kilometers of the conterminous U.S. (CONUS) river network were classified by waterbody type and origin (historic vs. human-made or intensively managed), surface areal coverage, and degree of connectivity as estimated by a change in water residence timescale in river corridors. Four centuries of human disturbance drove large swings in river corridor makeup, with a transition toward more lotic systems caused by beaver extirpation and abandonment of waterwheel mill ponds by end of the nineteenth century. The twentieth century saw a vast expansion (49%) in river corridor areal coverage resulting from construction and management of small ponds and reservoirs for drinking water, hydropower, irrigation and livestock watering, and stormwater control. Water residence timescale in river corridors doubled or quadrupled over large areas, and more in specific locations, during the twentieth century as a result of the increased coverage of reservoirs and managed small ponds. Although reservoirs and lakes now dominate river corridor surface areas, we found that the growing number of small ponds impacts a greater proportion of network length through their influence on headwater streams where most water and chemical runoff enters the river corridor. We close with an agenda for integrated modeling of the physical, biogeochemical, and ecological drivers of river corridor functions, trajectories of change, and management opportunities.

Diversity and distribution of landscape types in Norway

Norwegian landscapes are changing at an increasingly rapid rate, and systematically structured information about observable landscape variation is required for knowledge-based management of landscape diversity. Here we present the first version of a complete, area-covering, evidence-based landscape-type map of Norway, simultaneously addressing geo-ecological, bio-ecological and land-use related variation at the landscape level. We do so by applying map algebra operations on publicly available geographical data sets with full areal coverage for Norway. The type system used in the mapping is supported by systematically structured empirical evidence. We present the results of the mapping procedure, including the geographical distribution and descriptive statistics (abundance and areal coverage) for each of the identified landscape types. We identify nine major landscape types based on coarse-scale landform variation and, within the six inland and coastal major types, 284 minor landscape types are defined based on the composition of geo-ecological, bio-ecological, and land use-related landscape properties. The results provide new insights into the geography of Norwegian marine, coastal and inland landscapes. We discuss potential errors, uncertainties and limitations of the landscape-type maps, and address the potential value of this new tool for research, management and planning purposes.

Global Survey of Precipitation Properties Observed during Tropical Cyclogenesis and Their Differences Compared to Nondeveloping Disturbances

This study evaluates precipitation properties involved in tropical cyclogenesis by analyzing a multiyear, global database of passive microwave overpasses of the pregenesis stage of developing disturbances and nondeveloping disturbances. Precipitation statistics are quantified using brightness temperature proxies from the 85–91-GHz channels of multiple spaceborne sensors, as well as retrieved rain rates. Proxies focus on the overall raining area, areal coverage of deep convection, and the proximity of precipitation to the disturbance center. Of interest are the differences in those proxies for developing versus nondeveloping disturbances, how the properties evolve during the pregenesis stage, and how they differ globally. The results indicate that, of all of the proxies examined, the total raining area and rain volume near the circulation center are the most useful precipitation-related predictors for genesis. The areal coverage of deep convection also differentiates developing from nondeveloping disturbances and, similar to the total raining area, generally also increases during the pregenesis stage, particularly within a day of genesis. As the threshold convective intensity is increased, pregenesis cases are less distinguishable from nondeveloping disturbances. Relative to the western Pacific and Indian Oceans, the Atlantic and eastern North Pacific Oceans have less precipitation and deep convection observed during genesis and the smallest differences between developing and nondeveloping disturbances. This suggests that the total raining area and areal coverage of deep convection associated with tropical disturbances are better predictors of tropical cyclogenesis fate in the Pacific and Indian Oceans than in the Atlantic and eastern North Pacific.