News

18.04.2019 07:24 Age: 158 days

[Saral/AltiKa] Data information

Category: Operational news

 

Dear SARAL/Altika users,

 Please take note of the disclaimer below :

 SARAL/AltiKa satellite encounters since 3rd of February 2019 some issues affecting the nadir pointing accuracy. ISRO Operational Team in charge of the platform is doing many efforts to fix the issues and to recover a nominal mission as soon as possible.  

The availability and the quality of data measurements is degraded from time to time. Nevertheless, Cnes, EUMETSAT and ISRO have decided to continue the dissemination of the near real time and off-line products;  Therefore, before using the data, Users are invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²; otherwise standard quality flags may be used.

 

GDR cycle 126 (31 December 2018-04 February 2019 is just released today. It covers the beginning of the degraded period and you are encouraged to read the associated Cal/Val report available on AVISO+. In brief, during this cycle mispointing is quite larger than usual from pass 962 (03/02/2019 06:21:18 ) due to this attitude deviation. Hence a higher percentage of rejected measurements (up to  80%) is observed starting at pass 962. The attitude deviation also explains the higher percentage of missing measurements Users are advised not to use data with off_nadir_angle > 0.09deg².