{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T04:30:30Z","timestamp":1772253030685,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2019,11,22]],"date-time":"2019-11-22T00:00:00Z","timestamp":1574380800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In this paper, we present a framework to study the spatial structure of noctilucent clouds formed by ice particles in the upper atmosphere at mid and high latitudes during summer. We studied noctilucent cloud activity in optical images taken from three different locations and under different atmospheric conditions. In order to identify and distinguish noctilucent cloud activity from other objects in the scene, we employed linear discriminant analysis (LDA) with feature vectors ranging from simple metrics to higher-order local autocorrelation (HLAC), and histogram of oriented gradients (HOG). Finally, we propose a convolutional neural networks (CNN)-based method for the detection of noctilucent clouds. The results clearly indicate that the CNN-based approach outperforms the LDA-based methods used in this article. Furthermore, we outline suggestions for future research directions to establish a framework that can be used for synchronizing the optical observations from ground-based camera systems with echoes measured with radar systems like EISCAT in order to obtain independent additional information on the ice clouds.<\/jats:p>","DOI":"10.3390\/rs11232743","type":"journal-article","created":{"date-parts":[[2019,11,22]],"date-time":"2019-11-22T09:02:52Z","timestamp":1574413372000},"page":"2743","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Towards a Framework for Noctilucent Cloud Analysis"],"prefix":"10.3390","volume":"11","author":[{"given":"Puneet","family":"Sharma","sequence":"first","affiliation":[{"name":"Department of Automation &amp; Process Engineering (IAP), The Arctic University of Norway, 9037 Troms\u00f8, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Dalin","sequence":"additional","affiliation":[{"name":"The Swedish Institute of Space Physics, SE-98128 Kiruna, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2805-3265","authenticated-orcid":false,"given":"Ingrid","family":"Mann","sequence":"additional","affiliation":[{"name":"Department of Physics and Technology, The Arctic University of Norway, 9037 Troms\u00f8, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2841","DOI":"10.5194\/angeo-24-2841-2006","article-title":"Comparison of long-term Moscow and Danish NLC observations: Statistical results","volume":"24","author":"Dalin","year":"2006","journal-title":"Ann. Geophys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6681","DOI":"10.1029\/2018GL077719","article-title":"On the Anthropogenic Impact on Long-Term Evolution of Noctilucent Clouds","volume":"45","author":"Berger","year":"2018","journal-title":"Geophys. Res. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1090","DOI":"10.1016\/j.jastp.2010.07.004","article-title":"Observations of noctilucent clouds from Lithuania","volume":"72","author":"Dubietis","year":"2010","journal-title":"J. Atmos. Sol. -Terr. Phys."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1243","DOI":"10.5194\/angeo-26-1243-2008","article-title":"Noctilucent clouds observed from the UK and Denmark\u2014Trends and variations over 43 years","volume":"26","author":"Kirkwood","year":"2008","journal-title":"Ann. Geophys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1880-5981-66-98","article-title":"Noctilucent clouds observed from the ground: sensitivity to mesospheric parameters and long-term time series","volume":"66","author":"Pertsev","year":"2014","journal-title":"Earth Planets Space"},{"key":"ref_6","first-page":"8","article-title":"North American Noctilucent Cloud Observations in 1964\u201377 and 1988\u20132014: Analysis and Comparisons","volume":"110","author":"Zalcik","year":"2016","journal-title":"J. R. Astron. Soc. Can."},{"key":"ref_7","first-page":"148","article-title":"In Search of Trends in Noctilucent Cloud Incidence from the La Ronge Flight Service Station (55N 105W)","volume":"108","author":"Zalcik","year":"2014","journal-title":"J. R. Astron. Soc. Can"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3238","DOI":"10.1002\/2013JD021017","article-title":"Analysis of northern midlatitude noctilucent cloud occurrences using satellite data and modeling","volume":"119","author":"Russell","year":"2014","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2383","DOI":"10.1002\/2015JD024439","article-title":"Decadal variability in PMCs and implications for changing temperature and water vapor in the upper mesosphere","volume":"121","author":"Hervig","year":"2016","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"11271","DOI":"10.1002\/2016JA023080","article-title":"First wind shear observation in PMSE with the tristatic EISCAT VHF radar","volume":"121","author":"Mann","year":"2016","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2001RG000106","article-title":"Gravity wave dynamics and effects in the middle atmosphere","volume":"41","author":"Fritts","year":"2003","journal-title":"Rev. Geophys."},{"key":"ref_12","first-page":"9135","article-title":"Thermal structure of the Arctic summer mesosphere","volume":"104","year":"1999","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"19161","DOI":"10.1029\/96JD01213","article-title":"First simultaneous and common volume observations of noctilucent clouds and polar mesosphere summer echoes by lidar and radar","volume":"101","author":"Nussbaumer","year":"1996","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2601","DOI":"10.5194\/acp-4-2601-2004","article-title":"Polar mesosphere summer echoes (PMSE): Review of observations and current understanding","volume":"4","author":"Rapp","year":"2004","journal-title":"Atmos. Chem. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Schwartz, M.J., Lambert, A., Manney, G.L., Read, W.G., Livesey, N.J., Froidevaux, L., Ao, C.O., Bernath, P.F., Boone, C.D., and Cofield, R.E. (2008). Validation of the Aura Microwave Limb Sounder temperature and geopotential height measurements. J. Geophys. Res. Atmos., 113.","DOI":"10.1029\/2007JD008783"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1106","DOI":"10.1109\/TGRS.2006.864366","article-title":"Early validation analyses of atmospheric profiles from EOS MLS on the aura Satellite","volume":"44","author":"Froidevaux","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Gadsden, M., and Schr\u00f6der, W. (1989). Noctilucent Clouds (Physics and Chemistry in Space), Springer. [1st ed.].","DOI":"10.1007\/978-3-642-48626-5"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e201900005","DOI":"10.1002\/ctpp.201900005","article-title":"Radar studies of ionospheric dusty plasma phenomena","volume":"59","author":"Mann","year":"2019","journal-title":"Contrib. Plasma Phys."},{"key":"ref_19","unstructured":"Association, E.S. (2011). EISCAT European Incoherent Scatter Scientific Association Annual Report 2011, EISCAT Scientific Association."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Leyser, B.T., and Wong, A.Y. (2009). Powerful electromagnetic waves for active environmental research in geospace. Rev. Geophys., 47.","DOI":"10.1029\/2007RG000235"},{"key":"ref_21","unstructured":"Theodoridis, S., and Koutroumbas, K. (2008). Pattern Recognition, Academic Press. [4th ed.]."},{"key":"ref_22","unstructured":"Mika, S., Ratsch, G., Weston, J., Scholkopf, B., and Mullers, K.R. (1999, January 25). Fisher discriminant analysis with kernels. Proceedings of the Neural Networks for Signal Processing IX: Proceedings of the 1999 IEEE Signal Processing Society Workshop (Cat. No.98TH8468), Madison, WI, USA."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/j.2517-6161.1948.tb00008.x","article-title":"The Utilization of Multiple Measurements in Problems of Biological Classification","volume":"10","author":"Rao","year":"1948","journal-title":"J. R. Stat. Soc."},{"key":"ref_24","unstructured":"Nomoto, N., Shinohara, Y., Shiraki, T., Kobayashi, T., and Otsu, N. (2005, January 16\u201318). A New Scheme for Image Recognition Using Higher-Order Local Autocorrelation and Factor Analysis. Proceedings of the MVA2005 IAPR Conference on Machine Vision Applications, Tsukuba, Japan."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Uehara, K., Sakanashi, H., Nosato, H., Murakawa, M., Miyamoto, H., and Nakamura, R. (2017, January 5\u20138). Object detection of satellite images using multi-channel higher-order local autocorrelation. Proceedings of the IEEE International Conference on Systems, Man, and Cybernetics (SMC), Banff, AB, Canada.","DOI":"10.1109\/SMC.2017.8122799"},{"key":"ref_26","unstructured":"Dalal, N., and Triggs, B. (2017, January 20\u201326). Histograms of oriented gradients for human detection. Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR\u201905), San Diego, CA, USA."},{"key":"ref_27","unstructured":"Goodfellow, I., Bengio, Y., and Courville, A. (2016). Deep Learning, MIT Press."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.acha.2015.12.005","article-title":"Neural network with unbounded activation functions is universal approximator","volume":"43","author":"Sonoda","year":"2017","journal-title":"Appl. Comput. Harmon. Anal."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.zemedi.2018.11.002","article-title":"An overview of deep learning in medical imaging focusing on MRI","volume":"29","author":"Lundervold","year":"2019","journal-title":"Z. Med. Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1016\/S0893-6080(05)80131-5","article-title":"Multilayer feedforward networks with a nonpolynomial activation function can approximate any function","volume":"6","author":"Leshno","year":"1993","journal-title":"Neural Netw."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Long, J., Shelhamer, E., and Darrell, T. (2015, January 7\u201312). Fully convolutional networks for semantic segmentation. Proceedings of the 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Boston, MA, USA.","DOI":"10.1109\/CVPR.2015.7298965"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"11093","DOI":"10.1109\/ACCESS.2019.2891970","article-title":"Semi-Supervised Learning With Deep Embedded Clustering for Image Classification and Segmentation","volume":"7","author":"Enguehard","year":"2019","journal-title":"IEEE Access"},{"key":"ref_33","first-page":"75","article-title":"Eiscat_3d: A next-generation European radar system for upper-atmosphere and geospace research","volume":"2010","author":"Wannberg","year":"2010","journal-title":"Ursi Radio Sci. Bull."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/23\/2743\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:36:36Z","timestamp":1760189796000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/23\/2743"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,11,22]]},"references-count":33,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2019,12]]}},"alternative-id":["rs11232743"],"URL":"https:\/\/doi.org\/10.3390\/rs11232743","relation":{"has-preprint":[{"id-type":"doi","id":"10.20944\/preprints201910.0061.v1","asserted-by":"object"}]},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,11,22]]}}}