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The societal impacts of flash floods are more significant than any other weather-related hazard. They are often manifested in the form of damage to infrastructure, flooding of roadways and bridges, creating deadly hazards to motorists and inundation of crops and pasture. Some of these hazards can be anticipated and thus mitigated given effective warning systems. This study describes the tools proposed over recent decades in the USA to predict flash flooding and evaluates them using a common observational data set. Design recommendations for flash-flood forecasting systems are provided, taking into account today's availability of high-resolution rainfall data at scales commensurate with flash flooding, their archives, spatial data sets to describe physiographic properties, and ever-increasing computational resources.Editor D. Koutsoyiannis; Guest editor R.J. MooreCitation Gourley, J.J., Flamig, Z.L., Hong, Y., and Howard, K.W., 2014. Evaluation of past, present and future tools for radar-based flash-flood prediction in the USA. Hydrological Sciences Journal, 59 (7), 1377–1389. http://dx.doi.org/10.1080/02626667.2014.919391 [ABSTRACT FROM AUTHOR]

Little is known about air traffic controllers' preferred maneuvers to resolve conflicts between pairs of aircraft, despite the topic's importance of to the planned NextGen system. We analyzed 256 cases of conflict resolution maneuvering from radar track data from 5 U.S. air traffic control centers. Our results show the influences of conflict geometries on controllers' maneuver choices. [ABSTRACT FROM AUTHOR]

The temporal and spatial variability of sea-ice radar signatures in the Southern Ocean during late winter, spring and early summer from QuikSCAT data is presented. We observe a circumpolar and broad band of sea-ice close to the marginal ice zone that is characterized by very high radar backscatter. This feature is explained through detailed in situ observations of snow and sea-ice properties as well as in relation to meteorological conditions, which were derived from US National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data. Our results indicate that high backscatter regions are caused by metamorphous snow, which forms through re-freezing after short-term melt events. This process is connected with the episodic passes of low-pressure systems entraining warmer air from the north. South of the Antarctic Circumpolar Trough, sea-ice is not affected by this influence and shows spatially homogenous microwave signatures with low backscatter. [ABSTRACT FROM AUTHOR]

A modified scattering model-based speckle filter (SMBSF) based on the spatial proximity principle was applied to the analysis of phased array type L-band synthetic aperture radar (PALSAR) polarimetric data in the coastal environment of North Carolina, USA. The modified filter preserved polarimetric characteristics and further reduced speckle noise qualitatively and quantitatively. Classification accuracy using the SAR data filtered by the modified filter was improved, especially for the forest class. [ABSTRACT FROM AUTHOR]

The transfer of position responsibility between controllers is accomplished with a position relief briefing (PRB) conducted using standards and a checklist developed by the Federal Aviation Administration. In this study, expert judges indicated the items on the checklist that were referenced in briefings from 5 terminal radar approach controls. Briefings were short and routinely included information on only a subset of checklist items, often only traffic, and often in an order not consistent with the checklist. We explored different models to explain the PRB structure and the partial, unordered use of the checklist. We propose a working model of air traffic control shift change that assumes that controllers convey information from memory and only sometimes use the physical checklist to conduct the briefing. [ABSTRACT FROM AUTHOR]

The shuttle radar topography mission (SRTM), was flow on the space shuttle Endeavour in February 2000, with the objective of acquiring a digital elevation model of all land between 60° north latitude and 56° south latitude, using interferometric synthetic aperture radar (InSAR) techniques. The SRTM data are distributed at horizontal resolution of 1 arc-second (∼30 m) for areas within the USA and at 3 arc-second (∼90 m) resolution for the rest of the world. A resolution of 90 m can be considered suitable for the small or medium-scale analysis, but it is too coarse for more detailed purposes. One alternative is to interpolate the SRTM data at a finer resolution; it will not increase the level of detail of the original digital elevation model (DEM), but it will lead to a surface where there is the coherence of angular properties (i.e. slope, aspect) between neighbouring pixels, which is an important characteristic when dealing with terrain analysis. This work intents to show how the proper adjustment of variogram and kriging parameters, namely the nugget effect and the maximum distance within which values are used in interpolation, can be set to achieve quality results on resampling SRTM data from 3” to 1”. We present for a test area in western USA, which includes different adjustment schemes (changes in nugget effect value and in the interpolation radius) and comparisons with the original 1” model of the area, with the national elevation dataset (NED) DEMs, and with other interpolation methods (splines and inverse distance weighted (IDW)). The basic concepts for using kriging to resample terrain data are: (i) working only with the immediate neighbourhood of the predicted point, due to the high spatial correlation of the topographic surface and omnidirectional behaviour of variogram in short distances; (ii) adding a very small random variation to the coordinates of the points prior to interpolation, to avoid punctual artifacts generated by predicted points with the same location than original data points and; (iii) using a small value of nugget effect, to avoid smoothing that can obliterate terrain features. Drainages derived from the surfaces interpolated by kriging and by splines have a good agreement with streams derived from the 1” NED, with correct identification of watersheds, even though a few differences occur in the positions of some rivers in flat areas. Although the 1” surfaces resampled by kriging and splines are very similar, we consider the results produced by kriging as superior, since the spline-interpolated surface still presented some noise and linear artifacts, which were removed by kriging. [ABSTRACT FROM AUTHOR]

The article focuses on the establishment by the U.S. of radar bases in the Czech Republic, which were strongly opposed by the public despite approval by the government. The U.S. opened official negotiations with the Czech Republic and Poland over the establishment of the bases in January 2007. However, reports revealed that negotiations had already started as early as May 2002. A Communist youth organization was able to collect around 90,000 signatures opposing the establishment of the bases. Information about the arguments in support of the petition initiative is provided.

The capability to retrieve cloud base heights was developed under the US National Polar‐orbiting Operational Environmental Satellite System (NPOESS) programme as one of 27 data products to be created from data collected by the Visible Infrared Imager Radiometer Suite (VIIRS). First launch of the VIIRS sensor, which is the high‐resolution Earth imager of the NPOESS programme, comes on National Aeronautics & Space Administration's (NASA) NPOESS Preparatory Project (NPP). In preparation for this launch, extensive testing of the VIIRS cloud algorithms was completed to verify that product performance will satisfy system requirements before the cloud algorithms were hosted in the NPOESS ground processing centre. The approach taken to retrieve cloud base height converts cloud optical properties into a geometric thickness which is then subtracted from the cloud top height. Performance of the cloud base height algorithms has been verified recently using MODIS data, together with temporarily and spatial coincident observations of cloud thickness values made with the millimetre cloud radar operated at the US Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains site in Oklahoma. Of particular significance is the clear demonstration that both cloud optical properties and cloud base heights are retrieved accurately during night‐time conditions with the VIIRS algorithms, since neither of these products is currently produced by the NASA EOS programme. Based upon these analyses, the VIIRS cloud algorithms are expected to satisfy NPOESS requirements, making VIIRS the first operational satellite sensor capable of retrieving three‐dimensional cloud fields. [ABSTRACT FROM AUTHOR]

In this study the utility of NASA's Shuttle Imaging Radar-C (SIR-C) data are evaluated for wetland mapping and monitoring. The fully polarimetric L- and C-band data are used in hierarchical analysis and maximum likelihood classification techniques. Each map produced is compared with the Environmental Protection Agency's Multi Resolution Land Characteristics classification for pixelto-pixel accuracy assessment. Results show that both L- and C- band are necessary for detection of flooding beneath vegetated canopies. HH-polarization is found in this study and others to be better than VV for wetland discrimination. The cross-polarizations (HV or VH) are needed for discrimination of woody versus herbaceous vegetation. [ABSTRACT FROM AUTHOR]

Provides information on a cloud that appeared in the skies around Washington, D.C. on April 26, 2005. Impact of the clouds on U.S. President George W. Bush and Vice President Dick Cheney; Action taken by security teams regarding an alert from the radar of the U.S. Customs and Border Protection.

Reports on an experimental animal detection system in Yellowstone National Park designed to eliminate animal-vehicle collisions along a stretch of U.S. Highway 191. How bison, elk, deer and moose cause a break in a radar beam to trigger flashing lights on signs to warn drivers of the possible presence of wildlife; System designed by Sensor Technologies and Systems, Inc., and the Western Transportation Institute at Montana State University.