A Two-Dimensional Variational Analysis Method for NSCAT Ambiguity Removal: Methodology, Sensitivity, and Tuning

Hoffman, Ross N.; Leidner, S. Mark; Henderson, John M.; Atlas, Robert; Ardizzone, J.; Bloom, S. C.

doi:10.1175/1520-0426(2003)20<585:atdvam>2.0.co;2

Cited by 59 publications

(67 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The VAM [1] that was previously used for the assimilation of SSM/I wind speeds has been enhanced for the assimilation of data from multiple platforms at high resolution. In previous work we treated SSM/I wind speed data as a special type of scatterometer data.…”

Section: Methodsmentioning

confidence: 99%

“…(See Figure 1 for the temporal extent of the data sets analyzed in this work.) We previously described a variational analysis method (VAM) [1] that was used to combine wind speeds derived from the DMSP SSM/I satellites into a consistent global analysis at 1 x 1 degree resolution [2]. Under the NASA funded REASoN project, this work was significantly expanded.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

<title>Application of satellite surface wind data to ocean wind analysis</title>

2008

View full text Add to dashboard Cite

A new set of cross-calibrated, multi-satellite ocean surface wind data is described. The principal data set covers the global ocean for the period beginning in 1987 with six-hour and 25-km resolution, and is produced by combining all ocean surface wind speed observations from SSM/I, AMSR-E, and TMI, and all ocean surface wind vector observations from QuikSCAT and SeaWinds. An enhanced variational analysis method (VAM) performs quality control and combines these data with available conventional ship and buoy data and ECMWF analyses. The VAM analyses fit the data used very closely and contain small-scale structures not present in operational analyses. Comparisons with withheld WindSat observations are also shown to be very good. These data sets should be extremely useful to atmospheric and oceanic research, and to air-sea interaction studies.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

<title>Application of satellite surface wind data to ocean wind analysis</title>

2008

View full text Add to dashboard Cite

show abstract

“…[Results for the radius of maximum wind were found for winds of 34 kt (17.5 m s 21 ), 50 kt (25.7 m s 21 ), and 64 kt (32.9 m s 21 ) by Mueller et al (2006), Kossin et al (2007, IR-based), and Demuth et al (2004Demuth et al ( , 2006 and Bessho et al (2006, both AMSUbased)]. In addition, algorithms have been developed to obtain both wind speed and direction from the early European Remote Sensing (ERS)-½ scatterometer (Quilfen et al 1998), the National Aeronautics and Space Administration (NASA) Scatterometer (NSCAT; Polito et al 2000), the QuikSCAT satellite (Hoffman et al 2003), and the Advanced Scatterometer (ASCAT) from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).…”

Section: Introductionmentioning

confidence: 99%

Initial Maintenance of Tropical Cyclone Size in the Western North Pacific

Lee

Cheung

Fang

et al. 2010

Monthly Weather Review

View full text Add to dashboard Cite

A tropical cyclone (TC) size parameter, which is defined here as the radius of 15 m s 21 near-surface wind speed (R15), is calculated for 145 TCs in the western North Pacific during 2000-05 based on QuikSCAT oceanic winds. For the 73 TCs that intensified to typhoon intensity during their lifetimes, the 33% and 67% respective percentiles of R15 at tropical storm intensity and at typhoon intensity are used to categorize small, medium, and large TCs. Whereas many of the small TCs form from an easterly wave synoptic pattern, the monsoon-related formation patterns are favorable for forming medium to large TCs. Most of these 73 TCs stay in the same size category during intensification, which implies specific physical mechanisms for maintaining TC size in the basin. The 18 persistently large TCs from the tropical storm to the typhoon stage mostly have northwestward or north-northwestward tracks, while the 16 persistently small TCs either move westwardnorthwestward in lower latitudes or develop at higher latitudes with various track types. For the large TCs, strong low-level southwesterly winds exist in the outer core region south of the TC center throughout the intensification period. The small TCs are more influenced by the subtropical high during intensification. The conclusion is that it is the low-level environment that determines the difference between large and small size storms during the early intensification period in the western North Pacific.

show abstract

“…The addition of vorticity constraints on wind vectors was first developed by Hoffman [1984] to remove the ambiguity of the Seasate-A Satellite Scatterometer (SASS) winds. It was also employed by Legler et al [1989], Stoffelen and Anderson [1997], Hoffman et al [2003], and Atlas et al [1996,2011] in their studies.…”

Section: Methodsmentioning

confidence: 99%

Insights on the OAFlux ocean surface vector wind analysis merged from scatterometers and passive microwave radiometers (1987 onward)

Jin

2014

JGR Oceans

View full text Add to dashboard Cite

A high-resolution global daily analysis of ocean surface vector winds (1987 onward) was developed by the Objectively Analyzed air-sea Fluxes (OAFlux) project. This study addressed the issues related to the development of the time series through objective synthesis of 12 satellite sensors (two scatterometers and 10 passive microwave radiometers) using a least-variance linear statistical estimation. The issues include the rationale that supports the multisensor synthesis, the methodology and strategy that were developed, the challenges that were encountered, and the comparison of the synthesized daily mean fields with reference to scatterometers and atmospheric reanalyses. The synthesis was established on the bases that the low and moderate winds (<15 m s 21 ) constitute 98% of global daily wind fields, and they are the range of winds that are retrieved with best quality and consistency by both scatterometers and radiometers. Yet, challenges are presented in situations of synoptic weather systems due mainly to three factors: (i) the lack of radiometer retrievals in rain conditions, (ii) the inability to fill in the data voids caused by eliminating rainflagged QuikSCAT wind vector cells, and (iii) the persistent differences between QuikSCAT and ASCAT high winds. The study showed that the daily mean surface winds can be confidently constructed from merging scatterometers with radiometers over the global oceans, except for the regions influenced by synoptic weather storms. The uncertainties in present scatterometer and radiometer observations under high winds and rain conditions lead to uncertainties in the synthesized synoptic structures.

show abstract

A Two-Dimensional Variational Analysis Method for NSCAT Ambiguity Removal: Methodology, Sensitivity, and Tuning

Cited by 59 publications

References 51 publications

<title>Application of satellite surface wind data to ocean wind analysis</title>

<title>Application of satellite surface wind data to ocean wind analysis</title>

Initial Maintenance of Tropical Cyclone Size in the Western North Pacific

Insights on the OAFlux ocean surface vector wind analysis merged from scatterometers and passive microwave radiometers (1987 onward)

Contact Info

Product

Resources

About