At the Wegener Center of the University of Graz (WEGC) we employ the unique SI-traceable data from GNSS radio occultation (RO), available since 2001 and scheduled long-term into the future, to monitor the fundamental thermodynamic state of the atmosphere as determined by air density, pressure, temperature, and tropospheric water vapor, which are fundamental variables for tracking climate change and in fact fundamental to all weather and climate processes.
In a cornerstone endeavor at WEGC over 2013 to 2016, supported also by many international partner groups and funded mainly by the ASAP-9 to ASAP-11 programmes and ESA, we establish a novel Reference Occultation Processing System (rOPS). The rOPS monitors the atmosphere by SI-traced atmospheric profiling with integrated uncertainty propagation, for providing benchmark-quality reference RO data for cal/val and climate, complementary to near-real-time data for weather prediction (NWP).
The Radio Occultation Meteorology Satellite Application Facility (ROM SAF), part of the SAF Network of EUMETSAT and entering the next five-years Continuous Development and Operations Phase # 3 (CDOP-3) by March 2017, generates operational GNSS RO data for assimilation into numerical weather prediction (NWP) systems, re-processed climate data records (CDRs), a software package for RO processing (ROPP) and NWP applications, as well as operational monitoring of RO data streams. Its research and development activities are primarily geared towards developing new GNSS RO data products and improving existing products.
With the proposed ATROMSAF1 project WEGC and ROM SAF now aim to join forces and to enter a phase of intensified R&D partnership via a Federated Activity under CDOP-3 to foster high-quality RO data processing and climate applications, with the initial ATROMSAF1 goals jointly selected from high-priority GNSS RO advancement fields as follows:
- cross-evaluation between rOPS and ROM SAF/ROPP Level 2 data products from bending angles (L2a processing input) towards atmospheric profiles (L2b processing output), for close analysis of structural uncertainty, with one dedicated focus on non-spherical effects, benefitting from the co-estimation of systematic and random uncertainties by the rOPS;
- consistency evaluation of ROM SAF/ROPP re-processing climate data records over 2001 to 2016 by WEGC's rOPS, including ROM SAF's Obs4MIPs data records for the climate model community as well as the RO-CLIM data records by international RO centers, with a focus to identify, assess, understand and potentially mitigate remaining inconsistencies.
We expect this ATROMSAF1 work, which will be complemented by a EUMETSAT Visiting scientist activity on correction of residual ionospheric errors from ionospheric asymmetry, to be of substantial benefit both for improving ROM SAF's operational NWP and climate products as well as WEGC's rOPS towards further enhanced uncertainty quantification and reliability of its climate reference RO data.