Journal ArticleDOI
Sea State Impacts on Wind Speed Retrievals From C-Band Radars
TLDR
Analysis of data from advanced scatterometer (ASCAT) aboard MetOp-A and the advanced synthetic aperture radar (ASAR) aboard Envisat against the in situ buoy wind speeds finds that the sea state dominates the wind speed errors and these trends increase with the significant wave height.Abstract:
Scatterometers, a proven technology, provide ocean wind speeds and directions that are essential in operational forecasts, monitoring of the climate, and scientific applications. While the missions and geophysical model functions are performing well, challenges remain. We analyze data from advanced scatterometer (ASCAT) aboard MetOp-A and the advanced synthetic aperture radar (ASAR) aboard Envisat, both of which operate in the C-band, against the in situ buoy wind speeds. We observe large variability in the wind speed residuals. Through analysis of these residuals, we find that they are related to sea state effects and atmospheric stability. The sea state dependence created by low-frequency swells is more pronounced for the lower incidence angles in ASCAT. In ASAR with a fixed angle of $23^{\circ }$ , the sea state dominates the wind speed errors and these trends increase with the significant wave height. We observe that wind speeds from ASAR and ASCAT have a close resemblance, which helps us to extrapolate our findings. The synergy between the two technologies can be further exploited to improve wind speed retrievals. Future scatterometer missions, such as the next MetOp, will operate with the wider range of incidence angles (including lower angles) to increase their coverage together, have higher spatial resolution, and obtain measurements closer to the coasts. In these cases, high-resolution SAR data can aide in the understanding of the radar response.read more
Citations
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Journal ArticleDOI
Scientific Developments and the EPS-SG Scatterometer
Ad Stoffelen,Signe Aaboe,Jean-Christophe Calvet,James Cotton,Giovanna de Chiara,Julia Figa Saldana,Alexis Mouche,Marcos Portabella,Klaus Scipal,Wolfgang Wagner +9 more
TL;DR: The SCA instrument innovations are well set to provide timely benefits in all the main application areas of the scatterometer and can be expected to contribute to new and more sophisticated meteorological, oceanographic, land, sea ice, and climate services in the forthcoming SCA era.
Journal ArticleDOI
ERAstar: A High-Resolution Ocean Forcing Product
TL;DR: A new forcing product, ERA*, is developed by means of a geolocated scatterometer-based correction applied to the European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis or ERA-interim (hereafter referred to as ERAi), which successfully corrects for local wind vector biases present in the ERAi output globally.
Journal ArticleDOI
Retrieval of Sea Surface Wind Speeds from Gaofen-3 Full Polarimetric Data
TL;DR: In this article, the sea surface wind speed (SSWS) retrieval from Gaofen-3 (GF-3) quad-polarization stripmap (QPS) data in vertical-vertical (VV), horizontal-horizontal (HH), and vertical-orthogonal (VH) polarizations is investigated in detail based on 3170 scenes acquired from October 2016 to May 2018.
Journal ArticleDOI
Calibration of the Copolarized Backscattering Measurements From Gaofen-3 Synthetic Aperture Radar Wave Mode Imagery
TL;DR: Verification against the independent scatterometer-derived winds shows that after NWP-based ocean recalibration, the accuracy of wind speed retrieval from GF-3 wave mode imagery could reach the wind speed estimation performance using the state of theart of SAR data.
Journal ArticleDOI
Improving Altimeter Wind Speed Retrievals Using Ocean Wave Parameters
Haoyu Jiang,Hao Zheng,Lin Mu +2 more
TL;DR: Major wave heights and mean wave periods are effective in correcting U10 retrievals, probably due to the tilting modulation of long-waves on the sea surface, and the atmospheric instability can lead to errors on extrapolated buoy U10.
References
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Journal ArticleDOI
The influence of atmospheric stratification on scatterometer winds
TL;DR: In this paper, the importance of atmospheric stability effects for the analysis of scatterometer data is studied, and a variational analysis procedure for the scatterometers data, which adjusts both the near-surface velocity and temperature, is developed.
Journal ArticleDOI
Wind stress measurements from the QuikSCAT‐SeaWinds scatterometer tandem mission and the impact on an ocean model
TL;DR: In this paper, the authors examined diurnal signals captured by the QuikSCAT-SeaWinds scatterometer tandem mission (April-October 2003) and their impact on ocean model simulation and found that the impact of diurnal wind on model sea surface temperature (SST) is significantly larger with scatterometer than with NCEP winds because of stronger vertical mixing caused by the twice-daily scatterometer wind.
Journal ArticleDOI
In Situ and Satellite Evaluation of Air–Sea Flux Variation near Ocean Temperature Gradients
TL;DR: In this article, the authors used measurements of ocean-atmosphere coupling across persistent mesoscale sea surface temperature (SST) gradients to examine the controls of atmospheric stability, pressure gradient force, and heat flux that are considered central to oft-observed coupling between wind and SST.
Proceedings ArticleDOI
The relationship between radar backscatter cross section and ocean wave parameters at low incidence angles
TL;DR: Using collocated data set of Tropical Rainfall Mapping Mission (TRMM) precipitation radar (PR) and buoy wind and wave measurements, the relationship between the Ku-band radar backscatter cross section, radar incidence angle, buoy measured near surface wind speed in 10m (U10), significant wave height (SWH), wave steepness (℘), and wave age (β) is studied.