1

A new set of tools for all altimetry users

J. Benveniste (ESA), N. Picot (CNES), V. Rosmorduc (CLS) et al.

2

Basic Radar Altimetry Toolbox & Tutorial

• A Joint project between ESA and CNES• Statements:

– 16 years of altimetry available and at least as many data formats as satellites,– A growing number of non-expert users of the data,– Scientists also need easy-to-use data products and tools!

• Basic Radar Altimetry Toolbox (BRAT)– Data reading, processing and visualisation – All altimetry data from official data centres since ERS-1 (1991)

• Radar Altimetry Tutorial (RAT) – A tutorial describing altimetry, for the users– technique, applications and missions – Products fact sheets and data use cases

• Available on the web (http://www.altimetry.info, http://earth.esa.int/brat/), or on DVD

3

BRAT Data import & export

• Output NetCDF

• Ascii dump possible

• Image export (png, tif, jpg, bmp)

ERS-1 ERS-2

Topex/Poseidon

GFO

Jason-1

Envisat

Cryosat

Sensor data

Along-track

Gridded data

4

Radar Altimetry Tutorial• Applications

– Geodesy & solid Earth– Ocean– Ice– Climate– Weather– Hydrology & land– Coastal

• Data use cases• Altimetry

– How it works– Data flow– Future improvements

• Altimetry missions– Past missions– Current missions– Future missions

• Products– Data– Software– Documentation– Toolbox

http://www.altimetry.info http://earth.esa.int/brat/

5

Basic Radar Altimetry Toolbox software

• Windows & Linux• Open source

Data read & processed:• From several satellites

ERS-1 and 2, Topex/Poseidon, Geosat Follow-on, Jason-1, Envisat, and the future Cryosat missions.

• From several data centres ESA, Aviso, JPL/PoDaac, Noaa

• Of several processing levelsfrom Sensor Geophysical Data Record to gridded merged data

• Present version: v1.0.2

6

Software accessible at different levels

Data reading

.exe files

GUI

core functions (available from C, Fortran, Matlab, IDL APIs)

Select, compute and visualise data using command line mode with parameter files

Graphical User Interface (GUI):use the toolbox through a windowed interface

7

Formulas: saving expressions and selections

• Formulas are combinations of data fields and functions (including arithmetic operators, + - / *)

• Use: – as a ‘data expression’: to compute a combination of data fields (e.g.

Sea Surface Height)– or as a data selection: to do a complex selection on the data fields

• Pre-defined formulas can be used (Sea Surface Height, Sea Level Anomalies, ocean data editing for all satellite GDRs are built-in)

• User-made formulas can be saved and re-used in either the same workspace, or imported in another one Formulas can be exchanged between users

8

Maps (different projections)

Data visualisation

Curves

9

Data quick-look & visualisation

10

Data visualisation

11

Statistics

Mean Sea Level Anomalies for November

1997

+ Minimum, Maximum

12

Hurricane KatrinaJason-1 & T/P Envisat GFO

13

Southern swell, May 2007

Jason-1 OSDR, 12 May 2007

14

Ocean variability (SLA standard deviation over 15 years)

15

Sea level anomaly seasonal variationsAutumn Spring

Summer Winter

+ 15 cm- 15

16

Zoom

Kinetic Energy on 17 August 2005

17

For more information

www.altimetry.info with a mirror on

earth.esa.int/brat/