TY - JOUR
T1 - Seasonal Dependence of Geomagnetic Active-Time Northern High-Latitude Upper Thermospheric Winds
AU - Dhadly, Manbharat S.
AU - Emmert, John T.
AU - Drob, Douglas P.
AU - Conde, Mark G.
AU - Doornbos, Eelco
AU - Shepherd, Gordon G.
AU - Makela, Jonathan J.
AU - Wu, Qian
AU - Nieciejewski, Richard J.
AU - Ridley, Aaron J.
N1 - Funding Information:
This study was supported by NASA's Heliophysics Supporting Research Program (grant NNH16AC381). This work was conducted while Manbharat Singh Dhadly held a National Research Council's Research Associateship at Naval Research Laboratory, Washington, DC. Kp and F 10.7 indexes are available at NASA OMNIWeb data explorer (https://omniweb.gsfc.nasa.gov/). Poker Flat and Toolik Lake SDI data are available at http://sdiserver.gi.alaska.edu/sdiweb/index.asp. WINDII Level 2 data are available from Gordon Shepherd (gordon@yorku.ca). GOCE data can be obtained from https://earth.esa.int/web/guest/missions/esa-operational-missions/goce/goce-%20thermospheric-data. All other data sets can be obtained from the Madrigal database at http://cedar.openmadrigal.org/cgi-bin/accessData.cgi. Poker Flat and Toolik Lake SDI operations (during the observing periods included in this manuscript) were supported by the National Science Foundation through grants AGS1243476, AGS1140075, and AGS0821431. Resolute Bay data were supported by the National Science Foundation through grant AGS1339918. Data collection for the Urbana and Peach Mountain FPIs was supported by the National Science Foundation through grants AGS 1452291 and ATM1452097.
Publisher Copyright:
©2017. American Geophysical Union. All Rights Reserved.
PY - 2018/1
Y1 - 2018/1
N2 - This study is focused on improving the poorly understood seasonal dependence of northern high-latitude F region thermospheric winds under active geomagnetic conditions. The gaps in our understanding of the dynamic high-latitude thermosphere are largely due to the sparseness of thermospheric wind measurements. With current observational facilities, it is infeasible to construct a synoptic picture of thermospheric winds, but enough data with wide spatial and temporal coverage have accumulated to construct a meaningful statistical analysis. We use long-term data from eight ground-based and two space-based instruments to derive climatological wind patterns as a function of magnetic local time, magnetic latitude, and season. These diverse data sets possess different geometries and different spatial and solar activity coverage. The major challenge is to combine these disparate data sets into a coherent picture while overcoming the sampling limitations and biases among them. In our previous study (focused on quiet time winds), we found bias in the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) cross-track winds. Here we empirically quantify the GOCE bias and use it as a correction profile for removing apparent bias before empirical wind formulation. The assimilated wind patterns exhibit all major characteristics of high-latitude neutral circulation. The latitudinal extent of duskside circulation expands almost 10∘ from winter to summer. The dawnside circulation subsides from winter to summer. Disturbance winds derived from geomagnetic active and quiet winds show strong seasonal and latitudinal variability. Comparisons between wind patterns derived here and Disturbance Wind Model (DWM07) (which have no seasonal dependence) suggest that DWM07 is skewed toward summertime conditions.
AB - This study is focused on improving the poorly understood seasonal dependence of northern high-latitude F region thermospheric winds under active geomagnetic conditions. The gaps in our understanding of the dynamic high-latitude thermosphere are largely due to the sparseness of thermospheric wind measurements. With current observational facilities, it is infeasible to construct a synoptic picture of thermospheric winds, but enough data with wide spatial and temporal coverage have accumulated to construct a meaningful statistical analysis. We use long-term data from eight ground-based and two space-based instruments to derive climatological wind patterns as a function of magnetic local time, magnetic latitude, and season. These diverse data sets possess different geometries and different spatial and solar activity coverage. The major challenge is to combine these disparate data sets into a coherent picture while overcoming the sampling limitations and biases among them. In our previous study (focused on quiet time winds), we found bias in the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) cross-track winds. Here we empirically quantify the GOCE bias and use it as a correction profile for removing apparent bias before empirical wind formulation. The assimilated wind patterns exhibit all major characteristics of high-latitude neutral circulation. The latitudinal extent of duskside circulation expands almost 10∘ from winter to summer. The dawnside circulation subsides from winter to summer. Disturbance winds derived from geomagnetic active and quiet winds show strong seasonal and latitudinal variability. Comparisons between wind patterns derived here and Disturbance Wind Model (DWM07) (which have no seasonal dependence) suggest that DWM07 is skewed toward summertime conditions.
KW - F region neutral winds
KW - data assimilation
KW - geomagnetic active-time thermospheric winds
KW - high-latitude thermosphere
KW - ion-neutral coupling
KW - seasonal climatology
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U2 - 10.1002/2017JA024715
DO - 10.1002/2017JA024715
M3 - Article
AN - SCOPUS:85042270556
VL - 123
SP - 739
EP - 754
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9380
IS - 1
ER -