edu.ucar.opensky::articles:43157 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T17:56:12.280910 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.net/ark:/85065/d7bk1hrj Ocean surface retracking in tropical cyclones with the KaIA airborne radar altimeter 2025-02-01T00:00:00Z publication https://n2t.net/ark:/85065/d7bk1hrj https://doi.org/10.1109/JSTARS.2025.3542635 Bjorland, C. M. author Jelenak, Zorana author Sapp, J. W. author Shoup, C. G. author Isom, B. M. author Chang, P. S. author Carswell, J. author UCAR/NCAR - Library publisher <p><span style="-webkit-text-stroke-width:0px;background-color:rgb(255, 255, 255);color:rgb(51, 51, 51);display:inline !important;float:none;font-family:&quot;HelveticaNeue Regular&quot;, sans-serif;font-size:18px;font-style:normal;font-variant-caps:normal;font-variant-ligatures:normal;font-weight:400;letter-spacing:normal;orphans:2;text-align:start;text-decoration-color:initial;text-decoration-style:initial;text-decoration-thickness:initial;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;">KaIA is an airborne Ka-band radar altimeter capable of centimetric range resolution and near real-time significant wave height retrievals. Beginning in 2019, KaIA has been installed on National Oceanic and Atmospheric Administration (NOAA) WP-3D Hurricane Hunter aircraft to collect data in Atlantic tropical cyclones during the hurricane season, and extratropical cyclones during the winter storm season. This article details recent retracker algorithm innovations that address specific difficulties with airborne altimetry in extreme weather. Our two most significant contributions to retracker algorithm development are: 1) a higher-order expansion of the classic Brown (1977) altimetry waveform to accommodate off-nadir pointing angles up to 3.25</span><span class="MathJax" style="-webkit-text-stroke-width:0px;background-color:rgb(255, 255, 255);border-width:0px;box-sizing:border-box;color:rgb(51, 51, 51);direction:ltr;display:inline;float:none;font-family:&quot;HelveticaNeue Regular&quot;, sans-serif;font-size-adjust:none;font-size:18px;font-style:normal;font-variant-caps:normal;font-variant-ligatures:normal;font-weight:400;letter-spacing:normal;line-height:normal;margin:0px;max-height:none;max-width:none;min-height:0px;min-width:0px;orphans:2;overflow-wrap:normal;padding:0px;text-align:left;text-decoration-color:initial;text-decoration-style:initial;text-decoration-thickness:initial;text-indent:0px;text-transform:none;white-space:nowrap;widows:2;word-spacing:0px;" id="MathJax-Element-113-Frame" tabindex="0"><nobr style="border-width:0px;box-sizing:border-box;line-height:normal;margin:0px;max-height:none;max-width:none;min-height:0px;min-width:0px;padding:0px;text-decoration:none;transition:none;vertical-align:0px;white-space:nowrap !important;"><span class="math" style="border-width:0px;box-sizing:content-box;display:inline-block;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;width:0.507em;" id="MathJax-Span-2843"><span style="border-width:0px;box-sizing:content-box;display:inline-block;font-size:21.78px;height:0px;line-height:normal;margin:0px;padding:0px;position:relative;text-decoration:none;transition:none;vertical-align:0px;width:0.416em;"><span style="border-width:0px;box-sizing:content-box;clip:rect(1.38em, 1000.42em, 2.344em, -999.998em);display:inline;left:0em;line-height:normal;margin:0px;padding:0px;position:absolute;text-decoration:none;top:-2.202em;transition:none;vertical-align:0px;"><span class="mrow" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2844"><span class="msubsup" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2845"><span style="border-width:0px;box-sizing:content-box;display:inline-block;height:0px;line-height:normal;margin:0px;padding:0px;position:relative;text-decoration:none;transition:none;vertical-align:0px;width:0.416em;"><span style="border-width:0px;box-sizing:content-box;clip:rect(3.859em, 1000em, 4.135em, -999.998em);display:inline;left:0em;line-height:normal;margin:0px;padding:0px;position:absolute;text-decoration:none;top:-3.992em;transition:none;vertical-align:0px;"><span class="texatom" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2846"><span class="mrow" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2847"></span></span><span style="border-width:0px;box-sizing:content-box;display:inline-block;height:3.997em;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;width:0px;"></span></span><span style="border-width:0px;box-sizing:content-box;display:inline;left:0em;line-height:normal;margin:0px;padding:0px;position:absolute;text-decoration:none;top:-4.36em;transition:none;vertical-align:0px;"><span class="texatom" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2848"><span class="mrow" style="border-width:0px;box-sizing:content-box;display:inline;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2849"><span class="mo" style="border-width:0px;box-sizing:content-box;display:inline;font-family:MathJax_Main;font-size:15.3985px;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;" id="MathJax-Span-2850">∘</span></span></span><span style="border-width:0px;box-sizing:content-box;display:inline-block;height:3.997em;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;width:0px;"></span></span></span></span></span><span style="border-width:0px;box-sizing:content-box;display:inline-block;height:2.206em;line-height:normal;margin:0px;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:0px;width:0px;"></span></span></span><span style="border-bottom-style:initial;border-color:initial;border-image:initial;border-left-style:solid;border-right-style:initial;border-top-style:initial;border-width:0px;box-sizing:content-box;display:inline-block;height:0.947em;line-height:normal;margin:0px;overflow:hidden;padding:0px;position:static;text-decoration:none;transition:none;vertical-align:-0.053em;width:0px;"></span></span></nobr></span><span style="-webkit-text-stroke-width:0px;background-color:rgb(255, 255, 255);color:rgb(51, 51, 51);display:inline !important;float:none;font-family:&quot;HelveticaNeue Regular&quot;, sans-serif;font-size:18px;font-style:normal;font-variant-caps:normal;font-variant-ligatures:normal;font-weight:400;letter-spacing:normal;orphans:2;text-align:start;text-decoration-color:initial;text-decoration-style:initial;text-decoration-thickness:initial;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;">; 2) a GPS stabilization algorithm to enable along-track averaging while aircraft altitude is changing unpredictably. Comparisons against coincident measurements and modeled data are presented to validate algorithm improvements and document KaIA's performance throughout the 2021-2023 hurricane seasons. We measure less than 0.1 m bias in significant wave height retrievals relative to coincident satellite altimeters.</span></p> UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication <span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</span> None eng geoscientificInformation