English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Within the framework of sea-level rise projections, there is a strong need\udfor hindcast validation of the evolution of polar ice sheets in a way that\udtightly matches observational records (from radar, gravity, and altimetry\udobservations mainly). However, the computational requirements for making\udhindcast reconstructions possible are severe and rely mainly on the\udevaluation of the adjoint state of transient ice-flow models. Here, we look\udat the computation of adjoints in the context of the NASA/JPL/UCI Ice Sheet\udSystem Model (ISSM), written in C++ and designed for parallel execution with\udMPI. We present the adaptations required in the way the software is designed\udand written, but also generic adaptations in the tools facilitating the\udadjoint computations. We concentrate on the use of operator overloading\udcoupled with the AdjoinableMPI library to achieve the adjoint computation of\udthe ISSM. We present a comprehensive approach to (1) carry out type changing\udthrough the ISSM, hence facilitating operator overloading, (2) bind to\udexternal solvers such as MUMPS and GSL-LU, and (3) handle MPI-based\udparallelism to scale the capability. We demonstrate the success of the\udapproach by computing sensitivities of hindcast metrics such as the misfit to\udobserved records of surface altimetry on the northeastern Greenland Ice\udStream, or the misfit to observed records of surface velocities on Upernavik\udGlacier, central West Greenland. We also provide metrics for the scalability\udof the approach, and the expected performance. This approach has the\udpotential to enable a new generation of hindcast-validated projections that\udmake full use of the wealth of datasets currently being collected, or already\udcollected, in Greenland and Antarctica

An approach to computing discrete adjoints for MPI-parallelized models applied to Ice Sheet System Model 4.11