Browsing by Author "Valladares, C."
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Item Restricted Global equatorial plasma bubble occurrence during the 2015 St. Patrick's Day storm(American Geophysical Union, 2016-01-18) Carter, B. A.; Yizengaw, E.; Pradipta, R.; Retterer, J. M.; Groves, K.; Valladares, C.; Caton, R.; Bridgwood, C.; Norman, R.; Zhang, K.An analysis of the occurrence of equatorial plasma bubbles (EPBs) around the world during the 2015 St. Patrick's Day geomagnetic storm is presented. A network of 12 Global Positioning System receivers spanning from South America to Southeast Asia was used, in addition to colocated VHF receivers at three stations and four nearby ionosondes. The suppression of postsunset EPBs was observed across most longitudes over 2 days. The EPB observations were compared to calculations of the linear Rayleigh‐Taylor growth rate using coupled thermosphere‐ionosphere modeling, which successfully modeled the transition of favorable EPB growth from postsunset to postmidnight hours during the storm. The mechanisms behind the growth of postmidnight EPBs during this storm were investigated. While the latter stages of postmidnight EPB growth were found to be dominated by disturbance dynamo effects, the initial stages of postmidnight EPB growth close to local midnight were found to be controlled by the higher altitudes of the plasma (i.e., the gravity term). Modeling and observations revealed that during the storm the ionospheric plasma was redistributed to higher altitudes in the low‐latitude region, which made the plasma more susceptible to Rayleigh‐Taylor growth prior to the dominance of the disturbance dynamo in the eventual generation of postmidnight EPBs.Item Open Access Ionospheric disturbances associated with stratospheric sudden warmings(Instituto Geofísico del Perú, 2009) Goncharenko, L.; Coster, A.; Rideout, W.; Chau Chong Shing, Jorge Luis; Valladares, C.Diapositivas presentadas en: CEDAR Workshop 2009 del 28 de junio al 2 de julio de 2009 en Santa Fe, Nuevo México, USA.Item Open Access The LISN database: description and initial results(Instituto Geofísico del Perú, 2009) De la Jara, César; Chau Chong Shing, Jorge Luis; Espinoza, J. C.; Veliz, Oscar; Valladares, C.; Bullet, T.The heavy volume of data that GPS, ionosondes and magnetometers are continuously collecting is stored in the LISN server and managed using a set of rules that are intended to provide an efficiently way to manipulate the large data sets and also implement an adequate method to systematically transform all this information into knowledge. LISN integrates multiple data sources and should provide security, integrity and availability in a multi-user environment. Data from the remote stations arrives to the server continuously and is stored, processed and distributed. This data is easily available and in some cases freely accessible to the community promoting research and encouraging collaboration between users.