GRWG Web Meeting 2025-05-09

GSICS Microwave Radiometer Technology and Instrument Pre-Launch Testing and Post-Launch Characterization (TT) Focus Group Meeting

Agenda

1. Recommendation of SRF netCDF convention
2. Ed Kim (NASA) - NEON/SMBA Draft Requirements

Attendees

Jon Mittaz (U Reading)

Juyang Hu (CMA)

Karsten Fennig (DWD)

Shengli Wu (CMA)

Tiger Yang (U Maryland, NASA)

Tim Hewison (EUMETSAT)

Dazhen Gu (NIST) - Chair

Ed Kim (NASA)

Summary

Tim provided a summary of the GSICS annual meeting. Meeting minutes are available on GSICS wiki site (https://gsics.atmos.umd.edu/bin/view/Development/AnnualEP2025). Shenli’s MW report is also available (https://gsics.atmos.umd.edu/pub/Development/AnnualEP2025/13g%20GRWG%20MW%20Report_FIS.pptx).

We focused on the discussion of spectral response function (SRF) in NetCDF convention. An Overleaf document is started and most team members have access to edit and contribute to the document.

Dazhen talked about the background information and GSICS recommended improvements (see meeting slides for details)

Ed commented: SRF superseded the convention box-car response function and provided actual spectral shape of the receiver transfer function. This is supposed to benefit weather models.

SRF is publicly available for weather community.

Calibration can be done depending on receiver backend detection, either analog or digital.

Tiger commented: frequency needs to be vacuum corrected due to the variation of the speed of light. Ed commented: It only applies to certain cases, for example the filter is constructed by dielectrics which electromagnetic properties depend on the conditions of air and vacuum.

Ed commented about the normalization of the SRF. No unified way to specify the maximum. No common convention is available. Noise floor may be an important parameter but it is not included in the SRF information.

Ed also mentioned an ISO document “Calibration Requirements for Passive Microwave Sensors”. This may be relevant to some works pursued by GSICS focus groups.

Ed presented a talk about SMBA, the microwave part of new NOAA mission NEON. SMBA will replace ATMS and starts early launch in 2030 and ends its term in 2050. There will be ten years of overlap between ATMS and SMBA. Three fundamental instrument requirements: 1) Hyperspectral sounding, 2) RFI detection, 3) Intercalibration. Commercial builders will bid the contract set by NOAA. The bidding process is expected to start later 2025.

Ed provided SAM link to SMBA draft (https://sam.gov/opp/34f2e39ac9c0458aa90cb6e02ac2ef96/view).

We didn’t have time to discuss the action items due to limited members left after meeting running overtime. Dazhen will reach out to individuals for making progress of the SRF NetCDF document.