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The global impact of satellite-deriv...

Santek, David A.

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The global impact of satellite-derived polar winds on model forecasts.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	The global impact of satellite-derived polar winds on model forecasts./
Author:	Santek, David A.
Description:	114 p.
Notes:	Adviser: Steven A. Ackerman.
Contained By:	Dissertation Abstracts International68-08B.
Subject:	Atmospheric Sciences. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3278852
ISBN:	9780549196020

The global impact of satellite-derived polar winds on model forecasts.
Santek, David A.

The global impact of satellite-derived polar winds on model forecasts. - 114 p.

Adviser: Steven A. Ackerman.

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2007.

The use of Atmospheric Motion Vectors (AMVs) in Numerical Weather Prediction (NWP) models continues to be an important source of information in data sparse regions. These AMVs are derived from a time-sequence of images from geostationary and polar orbiting satellites. NWP centers have documented positive impact on model forecasts not only in regions where the AMVs are measured, but elsewhere as well. One example is the positive impact that the Moderate Resolution Imaging Spectroradiometer (MODIS) polar winds have on forecasts in the middle and subtropical latitudes, especially in 3 to 5 day forecasts and forecast bust situations. The MODIS winds are only derived poleward of 65° latitude. What are possible explanations for this global impact? This study investigates the hypothesis that the assimilation of polar winds modifies the flow in high latitudes near the polar jet stream and that this effect propagates to lower latitudes in extended forecasts.

ISBN: 9780549196020Subjects--Topical Terms:

1019179
Atmospheric Sciences.

The global impact of satellite-derived polar winds on model forecasts.
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020 $a 9780549196020
035 $a (UMI)AAI3278852
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100 1 $a Santek, David A. $3 1266237
245 1 4 $a The global impact of satellite-derived polar winds on model forecasts.
300 $a 114 p.
500 $a Adviser: Steven A. Ackerman.
500 $a Source: Dissertation Abstracts International, Volume: 68-08, Section: B, page: 5078.
502 $a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2007.
520 $a The use of Atmospheric Motion Vectors (AMVs) in Numerical Weather Prediction (NWP) models continues to be an important source of information in data sparse regions. These AMVs are derived from a time-sequence of images from geostationary and polar orbiting satellites. NWP centers have documented positive impact on model forecasts not only in regions where the AMVs are measured, but elsewhere as well. One example is the positive impact that the Moderate Resolution Imaging Spectroradiometer (MODIS) polar winds have on forecasts in the middle and subtropical latitudes, especially in 3 to 5 day forecasts and forecast bust situations. The MODIS winds are only derived poleward of 65° latitude. What are possible explanations for this global impact? This study investigates the hypothesis that the assimilation of polar winds modifies the flow in high latitudes near the polar jet stream and that this effect propagates to lower latitudes in extended forecasts.
520 $a Using a pre-operational version of the National Centers for Environmental Prediction's (NCEP) Global Forecast System (GFS), a side-by-side experiment was run for a six week period during the late summer of 2004, with and without the MODIS polar winds. Five forecast cases within this period were examined to determine how winds in the polar regions affect the wind and geopotential height fields in the jet stream region, resulting in changes in wave propagation speed.
520 $a From the five cases examined, it was determined that the addition of the polar winds modifies the mass balance in synoptic-scale waves near the polar jet streams, more consistently in data void regions. This change in mass balance is evident in differences in the ageostrophic wind, which has an effect on the speed and amplitude of baroclinic waves that extends from the jet stream into lower latitudes in later forecast times. These results reveal the substantial impact that polar-only observations have on the predictability of global weather systems.
590 $a School code: 0262.
650 4 $a Atmospheric Sciences. $3 1019179
690 $a 0725
710 2 $a The University of Wisconsin - Madison. $3 626640
773 0 $t Dissertation Abstracts International $g 68-08B.
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790 1 0 $a Ackerman, Steven A., $e advisor
791 $a Ph.D.
792 $a 2007
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