Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere
Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In An...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20110007352 2023-05-15T15:05:54+02:00 Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere Strahan, S. E. Krosschell, J. C. Douglass, A. R. Allen, D. R. Manney, G. L. Trueblood, J. Unclassified, Unlimited, Publicly available [2010] application/pdf http://hdl.handle.net/2060/20110007352 unknown Document ID: 20110007352 http://hdl.handle.net/2060/20110007352 Copyright, Distribution as joint owner in the copyright CASI Meteorology and Climatology 2010 ftnasantrs 2019-07-21T06:30:33Z Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from approximately 580 to 1100 K (approximately 25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N2O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the VanLeer Icosahedral Triangular Advection isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at approximately 70-90 deg N, marked with elevated N2O. GMI, Replay, and VITA all reliably simulted the spin-up of the FrIAC, although the GMI and Replay peak N2O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7th and 14th of April. The VITA and Replay simulations transported the N2O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical hear during the anticyclonic phase, and it thereby protected the embedded N20 anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N2O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with time-scales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N2O anomaly similar to NILS well into August. The VITA simulation also captured the horizontal structure of the FrIAC during this phase, but VITA eventually developed fine-scale N2O structure not observed in MLS data. Other/Unknown Material Arctic NASA Technical Reports Server (NTRS) Arctic Nils ENVELOPE(48.017,48.017,-68.067,-68.067) Merra ENVELOPE(12.615,12.615,65.816,65.816) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Meteorology and Climatology |
spellingShingle |
Meteorology and Climatology Strahan, S. E. Krosschell, J. C. Douglass, A. R. Allen, D. R. Manney, G. L. Trueblood, J. Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
topic_facet |
Meteorology and Climatology |
description |
Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from approximately 580 to 1100 K (approximately 25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N2O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the VanLeer Icosahedral Triangular Advection isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at approximately 70-90 deg N, marked with elevated N2O. GMI, Replay, and VITA all reliably simulted the spin-up of the FrIAC, although the GMI and Replay peak N2O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7th and 14th of April. The VITA and Replay simulations transported the N2O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical hear during the anticyclonic phase, and it thereby protected the embedded N20 anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N2O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with time-scales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N2O anomaly similar to NILS well into August. The VITA simulation also captured the horizontal structure of the FrIAC during this phase, but VITA eventually developed fine-scale N2O structure not observed in MLS data. |
author |
Strahan, S. E. Krosschell, J. C. Douglass, A. R. Allen, D. R. Manney, G. L. Trueblood, J. |
author_facet |
Strahan, S. E. Krosschell, J. C. Douglass, A. R. Allen, D. R. Manney, G. L. Trueblood, J. |
author_sort |
Strahan, S. E. |
title |
Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
title_short |
Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
title_full |
Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
title_fullStr |
Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
title_full_unstemmed |
Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere |
title_sort |
modeling the frozen-in anticyclone in the 2005 arctic summer stratosphere |
publishDate |
2010 |
url |
http://hdl.handle.net/2060/20110007352 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(48.017,48.017,-68.067,-68.067) ENVELOPE(12.615,12.615,65.816,65.816) |
geographic |
Arctic Nils Merra |
geographic_facet |
Arctic Nils Merra |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
CASI |
op_relation |
Document ID: 20110007352 http://hdl.handle.net/2060/20110007352 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766337598355144704 |