Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean

Work was completed on the height tendency diagnoses of two extratropical cyclones that occurred upstream from the blocking event studied previously. One developed explosively over water 60 to 36 hours before the block first appeared, while the second developed explosively over the southeastern Unite...

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Main Authors: Knabb, Richard D., Lupo, Anthony R., Uhl, Mary A., Smith, Phillip J., Lamberty, Gregory L.
Format: Other/Unknown Material
Language:unknown
Published: 1990
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Online Access:http://hdl.handle.net/2060/19910007200
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spelling ftnasantrs:oai:casi.ntrs.nasa.gov:19910007200 2023-05-15T17:36:34+02:00 Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean Knabb, Richard D. Lupo, Anthony R. Uhl, Mary A. Smith, Phillip J. Lamberty, Gregory L. Unclassified, Unlimited, Publicly available Oct 1, 1990 application/pdf http://hdl.handle.net/2060/19910007200 unknown Document ID: 19910007200 Accession ID: 91N16513 http://hdl.handle.net/2060/19910007200 No Copyright CASI METEOROLOGY AND CLIMATOLOGY NASA, Marshall Space Flight Center, NASA(MSFC FY90 Global Scale Atmospheric Processes Research Program Review; p 45-46 1990 ftnasantrs 2015-03-15T05:21:24Z Work was completed on the height tendency diagnoses of two extratropical cyclones that occurred upstream from the blocking event studied previously. One developed explosively over water 60 to 36 hours before the block first appeared, while the second developed explosively over the southeastern United States during the time of block formation. In both cases, both vorticity and temperature advection were consistently important forcing mechanisms. This is in contrast to the block itself, in which vorticity advection was easily the dominant forcing mechanism. Latent heat release was also significant, accounting for about 50 percent of the total height falls in the cyclone below 850 mb. Estimates of latent heat release were greatly enhanced by coupling parameterized estimates with values derived from GOES IR data using an algorithm developed by Marshall's F. R. Robertson. Among the difficulties encountered in this work was the identification of an appropriate lower boundary condition for the solution of the height tendency equation. The zero value currently used tends to yield underestimates of the lower troposphere height tendencies. To address this problem a new diagnostic technique was developed in cooperation with Dr. Peter Zwack of the University of Quebec at Montreal. Based on an equation Dr. Zwack had previously developed (the Zwack-Okossi development equation), researchers now have a relationship that is completely consistent with the height tendency equation and provides estimates of lower boundary geostrophic vorticity or height tendencies. Finally, comparison of the SAT (satellite data) and NOSAT (no satellite data) analyses is progressing well. The present focus is on both the new diagnostic technique and the SAT/NOSAT comparisons. The former is being tested on the southeastern United States cyclone case previously mentioned and compared with the height tendency diagnoses already completed. The latter are being examined for the blocking case described in the publications cited in this summary. In addition to obtaining statistics that will allow general comparison of the two analyses, it will be possible to determine whether conclusions about the dynamics of the block development are influenced by the analysis set used. Other/Unknown Material North Atlantic NASA Technical Reports Server (NTRS)
institution Open Polar
collection NASA Technical Reports Server (NTRS)
op_collection_id ftnasantrs
language unknown
topic METEOROLOGY AND CLIMATOLOGY
spellingShingle METEOROLOGY AND CLIMATOLOGY
Knabb, Richard D.
Lupo, Anthony R.
Uhl, Mary A.
Smith, Phillip J.
Lamberty, Gregory L.
Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
topic_facet METEOROLOGY AND CLIMATOLOGY
description Work was completed on the height tendency diagnoses of two extratropical cyclones that occurred upstream from the blocking event studied previously. One developed explosively over water 60 to 36 hours before the block first appeared, while the second developed explosively over the southeastern United States during the time of block formation. In both cases, both vorticity and temperature advection were consistently important forcing mechanisms. This is in contrast to the block itself, in which vorticity advection was easily the dominant forcing mechanism. Latent heat release was also significant, accounting for about 50 percent of the total height falls in the cyclone below 850 mb. Estimates of latent heat release were greatly enhanced by coupling parameterized estimates with values derived from GOES IR data using an algorithm developed by Marshall's F. R. Robertson. Among the difficulties encountered in this work was the identification of an appropriate lower boundary condition for the solution of the height tendency equation. The zero value currently used tends to yield underestimates of the lower troposphere height tendencies. To address this problem a new diagnostic technique was developed in cooperation with Dr. Peter Zwack of the University of Quebec at Montreal. Based on an equation Dr. Zwack had previously developed (the Zwack-Okossi development equation), researchers now have a relationship that is completely consistent with the height tendency equation and provides estimates of lower boundary geostrophic vorticity or height tendencies. Finally, comparison of the SAT (satellite data) and NOSAT (no satellite data) analyses is progressing well. The present focus is on both the new diagnostic technique and the SAT/NOSAT comparisons. The former is being tested on the southeastern United States cyclone case previously mentioned and compared with the height tendency diagnoses already completed. The latter are being examined for the blocking case described in the publications cited in this summary. In addition to obtaining statistics that will allow general comparison of the two analyses, it will be possible to determine whether conclusions about the dynamics of the block development are influenced by the analysis set used.
format Other/Unknown Material
author Knabb, Richard D.
Lupo, Anthony R.
Uhl, Mary A.
Smith, Phillip J.
Lamberty, Gregory L.
author_facet Knabb, Richard D.
Lupo, Anthony R.
Uhl, Mary A.
Smith, Phillip J.
Lamberty, Gregory L.
author_sort Knabb, Richard D.
title Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
title_short Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
title_full Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
title_fullStr Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
title_full_unstemmed Synoptic/planetary-scale interactions and blocking over the North Atlantic Ocean
title_sort synoptic/planetary-scale interactions and blocking over the north atlantic ocean
publishDate 1990
url http://hdl.handle.net/2060/19910007200
op_coverage Unclassified, Unlimited, Publicly available
genre North Atlantic
genre_facet North Atlantic
op_source CASI
op_relation Document ID: 19910007200
Accession ID: 91N16513
http://hdl.handle.net/2060/19910007200
op_rights No Copyright
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