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This study aims to quantify the portion of the Earth's outgoing radiation that is attributable to tropical cyclones (TCs). To accomplish this, we have developed a method that starts with an image processing algorithm which labels cloud pixels associated with a TC, based on the time series of brightness temperature images and best-track data. The labels attributable to the TC are then combined with radiation data to obtain the TC-related radiation throughout its lifetime. Preliminary results are shown for the North Atlantic Ocean in 2012 and 2013: In 2012, the average TC shortwave and longwave radiation contributed 0.039 PW (or 0.35%) and 0.099 PW (or 0.34%), respectively, to the total regional radiation; In 2013, the contribution due tot TCs decreased to 0.022 PW (or 0.19%) for SW, and 0.059 PW (or 0.20%) for LW radiation.

Based on 12 years (2004-2015) of GOES-East satellite infrared (IR) imagery over the North Atlantic basin, the diurnal cycle of the tropical cyclone (TC) Deviation Angle Variation (DAV) value is analysed, and a backward 24-hr time average DAV is selected to filter the noise in the DAV-TC intensity estimation. The effect of satellite observation angle on the DAV-TC intensity estimation is analysed in theory, in a case study, and in the longer-term statistics. Based on these results, an improvement to the DAV-TC intensity estimation is presented and evaluated in this study. The results show that, after taking the observation angle into account, the new DAV-TC intensity estimation is shown to produce smaller errors and higher correlations than the previous versions, especially for major hurricanes.

Collected sources for the different types of visualizations used in the field of polarization imaging are not extensive. Here, we survey and review the different visualization techniques in passive polarimetric imaging. Analysis of the methods is done by applying various concepts from the field of visualization. We provide recommendations for choosing a visualization based on the data structure, spatial frequency, and analysis goals.

For high-power electromagnetic (HPEM) applications at high-repetition rate, conventional microwave inverters based on pulse transformers are not practical. At high-repetition rates, the magnetic materials used in the inductive coupling saturate. In this paper, we present an alternate concept for an inverter based on the technology used for ultrawideband baluns which provides isolation through capacitive coupling. Design of the device is discussed through numerical modeling, and two implementations are built and demonstrated: a circuit element version and a transmission line version. The devices are demonstrated at charge voltages of 6 kV and repetition rates up to 100 Hz, with excellent performance between 20 MHz and 2.5 GHz. The circuit element device has a rise time of 445 ps with an insertion loss of less than 3 dB, while the transmission line device has a rise time of 240 ps with an insertion loss of less than 2 dB for most frequencies. The inverter is demonstrated as part of the feed network for a hyperband HPEM antenna with a differential input.

Most channeled polarimeters modulate the intensity in a single independent domain such as space, time, or wavenumber. Recently we proposed and modeled a concept for a system modulated simultaneously in space and time [Opt. Lett. 43, 2768 – 2771 (2018)] and demonstrated that superior performance could be obtained by trading off spatial and temporal bandwidth in the system. Here we present results from a prototype realization of such a system and demonstrate quantitatively that the spatial modulation transfer function of the imager can be improved by choosing the appropriate modulation strategy for a given scene spatial and temporal bandwidth. We demonstrate that a hybrid modulation system can achieve the high spatial frequency performance of a time modulated system for static scenes, or it can achieve the high temporal frequency performance of a spatially modulated system for rapidly varying scenes, and it can out perform both systems for scenes with intermediate bandwidth in both domains. Moreover, the physical system implementation is essentially the same for each system type, which in principle allows the reconstruction strategy to be selected in real-time by choosing the appropriate reconstruction filters.

In this paper, we present the first in-depth analysis of the bandwidth tradeoffs, error performance, and noise resiliency of full-Stokes micropolarizer array (MPA) designs. By applying our Fourier domain tools that provide a systematic way for arranging information carriers and allocating bandwidth, we develop a number of new full-Stokes MPA layouts and compare them to the existing full-Stokes MPAs in the literature, all of which use 2 × 2 pixel unit cells to build the MPA. We compare the reconstruction accuracy afforded by these traditional designs with the generalized 2 × L family of MPAs, a 3 × 3 tiling, as well as a 2 × 2 × 3 layout that uses multiple snapshots and trades off temporal resolution for spatial resolution. Of those systems, the hybrid spatiotemporally modulated 2 × 2 × 3 MPA provisions the most bandwidth and provides the highest reconstruction accuracy, while the modified 2 × L family remains the best performing single-snapshot MPA. Additionally, we study the degradation of reconstruction accuracy under the presence of systematic error in MPA fabrication. We find that reducing the amount of correlated error is by far the largest factor in ensuring robust performance.