CGMS-41 NOAA-WP-27
08 July 2013
Agenda Item: WGII/6
Discussed in WGII
NOAA’S PARTICIPATION IN THE 2ND ATMOSPHERIC MOTION VECTOR (AMV)
INTER-COMPARISON STUDY
In response to CGMS-40 Action 40.22
This paper summarizes NOAA’s participation in the second AMV inter-comparison study
being undertaken by the IWWG.
CGMS-41 NOAA-WP-27
08 July 2013
NOAA’s Participation in the 2nd Atmospheric Motion Vector (AMV)
Inter-Comparison Study
1
1
Jaime Daniels1, Wayne Bresky2, Steve Wanzong3 , and Chris Velden3
NOAA/NESDIS, Center for Satellite Applications and Research (STAR), USA
2
IMSG, Inc, USA
3
Cooperative Institute for Meteorological Satellite Studies (CIMSS)/
University of Wisconsin, USA
INTRODUCTION
A first “AMV inter-comparison study” was conducted between the years 2007 and 2009,
where the main objective was to compare the operational AMV algorithms of all satellite
wind producers, including the corresponding height assignments for cloudy AMVs, using a
common dataset of MSG/SEVIRI images and ancillary data. The study assessed how the data
from the various AMV producers inter-compared in terms of global coverage, speed and
direction. Several lessons were learned from this study that helped to refine the test strategies
and objectives for a second “AMV inter-comparison study”.
A work plan for a second “AMV inter-comparison study” was developed by the IWWG cochairs and discussed at the 11th International Winds Workshop (CGMS-39-EUMETSATWP-28). Discussions were generally focused on the common datasets to be used and the
specific tests to be performed with each dataset.
At CGMS-40, Action Item 40.22 was conceived: “CGMS members that have committed to
participate in the second AMV derivation inter-comparison project are invited to carry out the
study on the basis of the guidance provided by IWWG and the Meteosat data set provided by
EUMETSAT. All CGMS members to report on preliminary results at CGMS-41. Final
results should be presented at IWW12 in 2014.” CGMS-41-EUM-WP-07 describes the 2nd
AMV Intercomparison Study in more detail.
The purpose of this working paper is to summarize NOAA’s participation and contribution to
the second AMV inter-comparison study being undertaken by the IWWG.
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NOAA’s CONTRIBUTION
NOAA successfully generated all of the requested AMV datasets from the common datasets
for this study. EUMETSAT prepared the common satellite and ancillary datasets needed for
the study. An image triplet of Meteosat-9 images taken on the 17 September 2012 at 12:00,
12:15 and 12:30 UTC serves as the common satellite dataset.
Dataset 1: Full-disk MSG 10.8 image triplet, where each image in the triplet is the same, but
artificially shifted by a known amount: 4 pixels west, 2 pixels south for image 2; 8 pixels
west, 4 pixels south for image 3. The displacement between consecutive images, is therefore
the same in both cases.
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CGMS-41 NOAA-WP-27
08 July 2013
Dataset 2: Full-disk MSG 6.3, 7.2, 10.8, 12.0 and 13.4 image triplets, where each image is
different.
Figure 1 shows an example of wind barbs (left) for NOAA’s AMVs generated for Dataset 1
described above. As illustrated, all of the AMVs show displacements to the southwest as a
result of the artificial displacement imparted in the image triplet data. Of interest is the fact
that the AMV speeds (right) at the sub-satellite point equal 14.9 m/s which is the expected
wind speed given the imparted displacement.
Figure 1. Wind barbs (left) and contoured wind speeds (right) for AMVs generated from
Meteosat-9/SEVIRI long-wave infrared 10.8um image triplet corresponding to Dataset 1 of
the 2nd AMV Intercomparison Study.
All of the AMV datasets generated by NOAA were provided to NWC-SAF/AEMET who is
leading the analysis of the AMV datasets collected from all of the study participants.
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SUMMARY
NOAA is pleased to partake in the 2nd AMV Intercomparison Study that is being undertaken
by the IWWG. NOAA has generated the required AMV test datasets using its latest AMV
algorithm developed for GOES-R and looks forward to participating in discussions with other
CGMS members at IWW12 who also participated in this study about the intercomparison
results.
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