Current version: PenWP v2.0, December 2015

The Pencil Beam Wind Processor (PenWP) is a software package written mainly in Fortran 90 with some parts written in C for handling data from the SeaWinds (on QuikSCAT or ADEOS-II), OSCAT (on Oceansat-2), HSCAT (on HY-2A) and RapidScat (on the International Space Station) scatterometer instruments.

PenWP is intended to be a generic wind processor for Ku-band pencil beam scatterometer data. It will be adapted to handle data from future instruments like the OSCAT successor ScatSAT (from ISRO) once they become available.

PenWP generates surface winds based on pencil beam radar backscatter data. It allows performing the ambiguity removal with the Two-dimensional Variational Ambiguity Removal (2DVAR) method and it supports the Multiple Solution Scheme (MSS).

The output of PenWP consists of wind vectors which represent surface winds within the ground swath of the scatterometer.

Input of PenWP is Normalized Radar Cross Section (NRCS) data (in BUFR format – conversion tools from HDF5 are provided in the package). Output is written using the SeaWinds BUFR template or the KNMI BUFR template with generic wind section.

Apart from the scatterometer input data, PenWP needs Numerical Weather Prediction (NWP) model winds as a first guess for the Ambiguity Removal step. These data need to be provided in GRIB edition 1 or 2.

Documentation is available here.

If you have any questions concerning PenWP, please contact the NWP SAF helpdesk.