Article
 

Estimation of Time-Averaged Surface Divergence and Vorticity from Satellite Ocean Vector Winds

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/z890s011x

Descriptions

Attribute NameValues
Creator
Abstract
  • Two methods of computing the time-mean divergence and vorticity from satellite vector winds in rain-free (RF) and all-weather (AW) conditions are investigated. Consequences of removing rain-contaminated winds on the mean divergence and vorticity depend strongly on the order in which the time-average and spatial derivative operations are applied. Taking derivatives first and averages second (DFAS_RF) incorporates only those RF winds measured at the same time into the spatial derivatives. While preferable mathematically, this produces mean fields biased relative to their AW counterparts because of the exclusion of convergence and cyclonic vorticity often associated with rain. Conversely, taking averages first and derivatives second (AFDS_RF) incorporates all RF winds into the time-mean spatial derivatives, even those not measured coincidentally. While questionable, the AFDS_RF divergence and vorticity surprisingly appears qualitatively consistent with the AW means, despite using only RF winds. The analysis addresses whether the AFDS_RF method accurately estimates the AW mean divergence and vorticity.Model simulations indicate that the critical distinction between these two methods is the inclusion of typically convergent and cyclonic winds bordering rain patches in the AFDS_RF method. While this additional information removes some of the sampling bias in the DFAS_RF method, it is shown that the AFDS_RF method nonetheless provides only marginal estimates of the mean AW divergence and vorticity given sufficient time averaging and spatial smoothing. Use of the AFDS_RF method is thus not recommended.
  • C-2013 ASCAT data are produced by Remote Sensing Systems and sponsored by the NASA Ocean Vector Winds Science Team. The JPL version 3 QuikSCAT dataset (https://podaac.jpl.nasa.gov/dataset/QSCAT_LEVEL_2B_OWV_COMP_12) was obtained via the PO.DAAC web portal and was processed by the SeaWinds Processing and Analysis Center (SeaPAC).
  • This is the publisher’s final pdf. The published article is copyrighted by American Meteorological Society and can be found at: https://www2.ametsoc.org/ams/index.cfm/publications/journals/journal-of-climate/
  • Keywords: North Atlantic Ocean, Satellite observations, Error analysis, Mesoscale models, Marine boundary layer
Resource Type
DOI
Date Available
Date Issued
Citation
  • O’Neill, L. W., Haack, T., & Durland, T. (2015). Estimation of Time-Averaged Surface Divergence and Vorticity from Satellite Ocean Vector Winds. Journal of Climate, 28(19), 7596-7620. doi:10.1175/JCLI-D-15-0119.1
Journal Title
Journal Volume
  • 28
Journal Issue/Number
  • 19
Rights Statement
Funding Statement (additional comments about funding)
  • This work was supported by NASA Grants NNX11AF31G and NNX10AO93G for funding of NASA's Ocean Vector Winds Science Team activities.
Publisher
Peer Reviewed
Language
Replaces

Relationships

Parents:

This work has no parents.

Items

Thumbnail Title Date Uploaded Visibility Actions
file details ONeillLarryCEOASEstimationTimeAverage.pdf 2017-10-27 Public Download