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Analysis of northern midlatitude noctilucent cloud occurrences using satellite data and modeling
Author(s) -
Russell James M.,
Rong Pingping,
Hervig Mark E.,
Siskind David E.,
Stevens Michael H.,
Bailey Scott M.,
Gumbel Jörg
Publication year - 2014
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd021017
Subject(s) - middle latitudes , satellite , latitude , environmental science , atmospheric sciences , climatology , cloud top , meteorology , geology , geography , geodesy , physics , astronomy
Motivated by numerous ground‐based noctilucent cloud (NLC) sightings at latitudes as low as ~40°N in recent years, we have conducted a study to determine if there have been any systematic NLC increases in the midnorthern latitudes. This question is addressed through investigating both the measured and modeled polar mesospheric cloud (PMC) occurrence frequencies. Temperature measured by the SABER instrument on the TIMED satellite over the 2002–2011 time period and a 7 year water vapor climatology developed from the data measured by the MLS instrument on the Aura satellite for the 2005–2011 period are used to simulate midlatitude PMCs. PMCs measured by the OSIRIS instrument on the Odin satellite and the SHIMMER instrument on the STPSat‐1 satellite are used to extensively validate the model‐generated PMC results. After validating the model against the PMC data, the model results were used to examine changes in the PMCs at midlatitudes between 2002 and 2011. The results show a statistically significant increase in the number of PMCs each season in the latitude range 40°N–55°N for the 10 year period examined. Increases in cloud frequency appear to be driven by the corresponding temperature decreases over the same time period. During this time, solar activity decreased from an active to a quiet period, which might have been partially responsible for the temperature decrease over this time period.