Real-time Targeted Observing Guidance :
Adjoint-Derived Sensitivity Steering Vector (ADSSV)

provided by Typhoon Dynamics Research Center, Department of Atmospheric Science, National Taiwan University

Active Tropical Cyclones

Currently no ADSSV product for active tropical cyclones.


Western Pacific

- 2012 Season

- 2011 Season

- 2010 Season

- 2009 Season

- 2008 Season

- 2007 Season


- 2007 Season

Product Description

This website is a (experimental) real-time targeted observing guidance, providing ADSSV figures for most of (but not all) tropical cyclones over the western North Pacific and Atlantic. ADSSV is a method based on the adjoint sensitivity to identify the sensitive areas at the observing time with respect to the typhoon steering flow at the verifying time.

The product is calculated by the MM5 adjoint model system using the NECP forecast as the initial and boundary condition. The observing time (To) and the verifying time (Tv) are 48 and 96 hours after the initial time (Ti), respectively. The dashed box represents the verifying area. The solid typhoon symbol shows the typhoon center at the observation time and the following MM5 forecast typhoon track is indicated by the empty typhoon symbols.

At a given point, the magnitude of the ADSSV, which has been normalized by the maximum value of the domain, shows the sensitivities of the typhoon steering flow to the vorticity field at the observing time. Meanwhile, the direction of the ADSSV shows the direction toward which the steering flow would increase with respect to a vorticity perturbation placed at that point.

More details of ADSSV can be found in Wu et al. (2007, JAS)

Related Links

- ETKF Products

- NRL SV Products

- JMA SV Products

- DLM Wind Variance Products

- Dropwindsonde Observations for Typhoon Surveillance near the TAiwan Region (DOTSTAR)