Directivity of wind vectors derived from the ERS-1/AMI scatterometer

Naoto Ebuchi, Hans C Graber

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Directional distribution of the wind vectors observed by the ERS-1 active microwave instrument (AMI) scatterometer over the global oceans is investigated to examine effects of errors in the geophysical model function used to retrieve the wind vectors from backscattering measurements. Three scatterometer data products, together with wind data derived from two operational meteorological analysis models, are analyzed and compared with each other for a period of 2 months. Frequency distributions of the wind directions relative to the midbeam looking direction are calculated in bins of 10°. It is found that scatterometer-derived wind vectors may exhibit systematic directional preference relative to the antenna beams in comparison with those of the model winds. This artificial directivity is considered to be caused by imperfections in the model function used to retrieve the wind vectors. Dependencies of the directional distributions on incidence angle and wind speed are also discussed for each data products. The distribution of wind directions is very sensitive to the errors in the model function and can be used as an effective measure of self-consistency to validate the model function and retrieved wind vectors.

Original languageEnglish (US)
Pages (from-to)7787-7797
Number of pages11
JournalJournal of Geophysical Research C: Oceans
Volume103
Issue number3334
StatePublished - 1998

Fingerprint

ERS-1 (ESA satellite)
scatterometers
scatterometer
directivity
Microwaves
microwaves
data products
wind direction
global ocean
microwave
ERS
frequency distribution
antenna
wind velocity
Bins
Backscattering
backscattering
oceans
antennas
incidence

ASJC Scopus subject areas

  • Oceanography
  • Astronomy and Astrophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Geophysics
  • Geochemistry and Petrology

Cite this

Directivity of wind vectors derived from the ERS-1/AMI scatterometer. / Ebuchi, Naoto; Graber, Hans C.

In: Journal of Geophysical Research C: Oceans, Vol. 103, No. 3334, 1998, p. 7787-7797.

Research output: Contribution to journalArticle

@article{b37715cc20e147458a06255d0cbd5192,
title = "Directivity of wind vectors derived from the ERS-1/AMI scatterometer",
abstract = "Directional distribution of the wind vectors observed by the ERS-1 active microwave instrument (AMI) scatterometer over the global oceans is investigated to examine effects of errors in the geophysical model function used to retrieve the wind vectors from backscattering measurements. Three scatterometer data products, together with wind data derived from two operational meteorological analysis models, are analyzed and compared with each other for a period of 2 months. Frequency distributions of the wind directions relative to the midbeam looking direction are calculated in bins of 10°. It is found that scatterometer-derived wind vectors may exhibit systematic directional preference relative to the antenna beams in comparison with those of the model winds. This artificial directivity is considered to be caused by imperfections in the model function used to retrieve the wind vectors. Dependencies of the directional distributions on incidence angle and wind speed are also discussed for each data products. The distribution of wind directions is very sensitive to the errors in the model function and can be used as an effective measure of self-consistency to validate the model function and retrieved wind vectors.",
author = "Naoto Ebuchi and Graber, {Hans C}",
year = "1998",
language = "English (US)",
volume = "103",
pages = "7787--7797",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
publisher = "Wiley-Blackwell",
number = "3334",

}

TY - JOUR

T1 - Directivity of wind vectors derived from the ERS-1/AMI scatterometer

AU - Ebuchi, Naoto

AU - Graber, Hans C

PY - 1998

Y1 - 1998

N2 - Directional distribution of the wind vectors observed by the ERS-1 active microwave instrument (AMI) scatterometer over the global oceans is investigated to examine effects of errors in the geophysical model function used to retrieve the wind vectors from backscattering measurements. Three scatterometer data products, together with wind data derived from two operational meteorological analysis models, are analyzed and compared with each other for a period of 2 months. Frequency distributions of the wind directions relative to the midbeam looking direction are calculated in bins of 10°. It is found that scatterometer-derived wind vectors may exhibit systematic directional preference relative to the antenna beams in comparison with those of the model winds. This artificial directivity is considered to be caused by imperfections in the model function used to retrieve the wind vectors. Dependencies of the directional distributions on incidence angle and wind speed are also discussed for each data products. The distribution of wind directions is very sensitive to the errors in the model function and can be used as an effective measure of self-consistency to validate the model function and retrieved wind vectors.

AB - Directional distribution of the wind vectors observed by the ERS-1 active microwave instrument (AMI) scatterometer over the global oceans is investigated to examine effects of errors in the geophysical model function used to retrieve the wind vectors from backscattering measurements. Three scatterometer data products, together with wind data derived from two operational meteorological analysis models, are analyzed and compared with each other for a period of 2 months. Frequency distributions of the wind directions relative to the midbeam looking direction are calculated in bins of 10°. It is found that scatterometer-derived wind vectors may exhibit systematic directional preference relative to the antenna beams in comparison with those of the model winds. This artificial directivity is considered to be caused by imperfections in the model function used to retrieve the wind vectors. Dependencies of the directional distributions on incidence angle and wind speed are also discussed for each data products. The distribution of wind directions is very sensitive to the errors in the model function and can be used as an effective measure of self-consistency to validate the model function and retrieved wind vectors.

UR - http://www.scopus.com/inward/record.url?scp=0032522013&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032522013&partnerID=8YFLogxK

M3 - Article

VL - 103

SP - 7787

EP - 7797

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 3334

ER -