date: 2026-07-07T12:16:17Z pdf:PDFVersion: 1.7 pdf:docinfo:title: Filling Satellite Microwave Observation Gaps via Generative Synthesis xmp:CreatorTool: LaTeX with hyperref access_permission:can_print_degraded: true subject: Polar-orbiting microwave radiometers provide indispensable all-weather measurements of the atmospheric state, yet revisit intervals of many hours leave critical gaps during rapidly evolving weather events. To address this limitation, we developed MIDAS (Microwave Inference via Diffusion Across Satellites), a probabilistic framework that estimates microwave brightness temperature (BT) fields across the geostationary full-disk domain from infrared observations at 10 min intervals. This study focuses on the five Microwave Humidity Sounder-2 (MWHS-2) humidity-sounding channels near 183 GHz, which provide vertically resolved water vapor information. MIDAS achieves relative errors below 0.5% for the majority of cases, with a channel-averaged mean absolute error of 1.15 K, outperforming a deterministic U-Net baseline (1.43 K). Beyond per-sample evaluation, MIDAS reproduces large-scale climatological patterns across the full-disk domain over a three-month summer period, consistent with Radiative Transfer for TOVS?Scattering (RTTOV-SCATT) simulations. In deep convective scenes where reconstruction is most difficult, the ensemble spread naturally tracks reconstruction difficulty, providing a built-in indicator of prediction confidence. Notably, MIDAS incorporates real-time polar-orbiting observations as physical constraints via a merge-sampling mechanism, reducing ensemble RMSE by over 20% and improving probabilistic calibration by more than 30%. Proof-of-concept assimilation experiments for two high-impact weather cases show that MIDAS-generated fields yield forecast improvements comparable to those from real satellite observations, reducing tropical cyclone track errors from approximately 110 km to 40 km and improving heavy precipitation forecasts at extreme rainfall thresholds where direct infrared assimilation shows no benefit. Overall, our framework demonstrates the potential of generative models to supplement sparse observational coverage and provide physically plausible microwave humidity fields for downstream applications. dc:format: application/pdf; version=1.7 pdf:docinfo:creator_tool: LaTeX with hyperref access_permission:fill_in_form: true pdf:encrypted: false dc:title: Filling Satellite Microwave Observation Gaps via Generative Synthesis modified: 2026-07-07T12:16:17Z cp:subject: Polar-orbiting microwave radiometers provide indispensable all-weather measurements of the atmospheric state, yet revisit intervals of many hours leave critical gaps during rapidly evolving weather events. To address this limitation, we developed MIDAS (Microwave Inference via Diffusion Across Satellites), a probabilistic framework that estimates microwave brightness temperature (BT) fields across the geostationary full-disk domain from infrared observations at 10 min intervals. This study focuses on the five Microwave Humidity Sounder-2 (MWHS-2) humidity-sounding channels near 183 GHz, which provide vertically resolved water vapor information. MIDAS achieves relative errors below 0.5% for the majority of cases, with a channel-averaged mean absolute error of 1.15 K, outperforming a deterministic U-Net baseline (1.43 K). Beyond per-sample evaluation, MIDAS reproduces large-scale climatological patterns across the full-disk domain over a three-month summer period, consistent with Radiative Transfer for TOVS?Scattering (RTTOV-SCATT) simulations. In deep convective scenes where reconstruction is most difficult, the ensemble spread naturally tracks reconstruction difficulty, providing a built-in indicator of prediction confidence. Notably, MIDAS incorporates real-time polar-orbiting observations as physical constraints via a merge-sampling mechanism, reducing ensemble RMSE by over 20% and improving probabilistic calibration by more than 30%. Proof-of-concept assimilation experiments for two high-impact weather cases show that MIDAS-generated fields yield forecast improvements comparable to those from real satellite observations, reducing tropical cyclone track errors from approximately 110 km to 40 km and improving heavy precipitation forecasts at extreme rainfall thresholds where direct infrared assimilation shows no benefit. Overall, our framework demonstrates the potential of generative models to supplement sparse observational coverage and provide physically plausible microwave humidity fields for downstream applications. pdf:docinfo:subject: Polar-orbiting microwave radiometers provide indispensable all-weather measurements of the atmospheric state, yet revisit intervals of many hours leave critical gaps during rapidly evolving weather events. To address this limitation, we developed MIDAS (Microwave Inference via Diffusion Across Satellites), a probabilistic framework that estimates microwave brightness temperature (BT) fields across the geostationary full-disk domain from infrared observations at 10 min intervals. This study focuses on the five Microwave Humidity Sounder-2 (MWHS-2) humidity-sounding channels near 183 GHz, which provide vertically resolved water vapor information. MIDAS achieves relative errors below 0.5% for the majority of cases, with a channel-averaged mean absolute error of 1.15 K, outperforming a deterministic U-Net baseline (1.43 K). Beyond per-sample evaluation, MIDAS reproduces large-scale climatological patterns across the full-disk domain over a three-month summer period, consistent with Radiative Transfer for TOVS?Scattering (RTTOV-SCATT) simulations. In deep convective scenes where reconstruction is most difficult, the ensemble spread naturally tracks reconstruction difficulty, providing a built-in indicator of prediction confidence. Notably, MIDAS incorporates real-time polar-orbiting observations as physical constraints via a merge-sampling mechanism, reducing ensemble RMSE by over 20% and improving probabilistic calibration by more than 30%. Proof-of-concept assimilation experiments for two high-impact weather cases show that MIDAS-generated fields yield forecast improvements comparable to those from real satellite observations, reducing tropical cyclone track errors from approximately 110 km to 40 km and improving heavy precipitation forecasts at extreme rainfall thresholds where direct infrared assimilation shows no benefit. Overall, our framework demonstrates the potential of generative models to supplement sparse observational coverage and provide physically plausible microwave humidity fields for downstream applications. pdf:docinfo:creator: Han Du, Baoxiang Pan, Fan Ping, Jin Xu, Congyi Nai, Sencan Sun, Jie Chao, Jingnan Wang, Shangshang Yang, Xi Chen, Jingyuan Li, Jiahua Mao, Lei Yin, Yupeng Li and Ziniu Xiao PTEX.Fullbanner: This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023) kpathsea version 6.3.5 meta:author: Han Du, Baoxiang Pan, Fan Ping, Jin Xu, Congyi Nai, Sencan Sun, Jie Chao, Jingnan Wang, Shangshang Yang, Xi Chen, Jingyuan Li, Jiahua Mao, Lei Yin, Yupeng Li and Ziniu Xiao trapped: False meta:creation-date: 2026-07-07T12:08:27Z created: 2026-07-07T12:08:27Z access_permission:extract_for_accessibility: true Creation-Date: 2026-07-07T12:08:27Z Author: Han Du, Baoxiang Pan, Fan Ping, Jin Xu, Congyi Nai, Sencan Sun, Jie Chao, Jingnan Wang, Shangshang Yang, Xi Chen, Jingyuan Li, Jiahua Mao, Lei Yin, Yupeng Li and Ziniu Xiao producer: pdfTeX-1.40.25; modified using OpenPDF 1.4.2 pdf:docinfo:producer: pdfTeX-1.40.25; modified using OpenPDF 1.4.2 pdf:unmappedUnicodeCharsPerPage: 0 Keywords: microwave radiometer; generative model; cross-platform synthesis; observation gap-filling; assimilation access_permission:modify_annotations: true dc:creator: Han Du, Baoxiang Pan, Fan Ping, Jin Xu, Congyi Nai, Sencan Sun, Jie Chao, Jingnan Wang, Shangshang Yang, Xi Chen, Jingyuan Li, Jiahua Mao, Lei Yin, Yupeng Li and Ziniu Xiao dcterms:created: 2026-07-07T12:08:27Z Last-Modified: 2026-07-07T12:16:17Z dcterms:modified: 2026-07-07T12:16:17Z title: Filling Satellite Microwave Observation Gaps via Generative Synthesis Last-Save-Date: 2026-07-07T12:16:17Z pdf:docinfo:keywords: microwave radiometer; generative model; cross-platform synthesis; observation gap-filling; assimilation pdf:docinfo:modified: 2026-07-07T12:16:17Z meta:save-date: 2026-07-07T12:16:17Z pdf:docinfo:custom:PTEX.Fullbanner: This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023) kpathsea version 6.3.5 Content-Type: application/pdf X-Parsed-By: org.apache.tika.parser.DefaultParser creator: Han Du, Baoxiang Pan, Fan Ping, Jin Xu, Congyi Nai, Sencan Sun, Jie Chao, Jingnan Wang, Shangshang Yang, Xi Chen, Jingyuan Li, Jiahua Mao, Lei Yin, Yupeng Li and Ziniu Xiao dc:subject: microwave radiometer; generative model; cross-platform synthesis; observation gap-filling; assimilation access_permission:assemble_document: true xmpTPg:NPages: 37 pdf:charsPerPage: 3155 access_permission:extract_content: true access_permission:can_print: true pdf:docinfo:trapped: False meta:keyword: microwave radiometer; generative model; cross-platform synthesis; observation gap-filling; assimilation access_permission:can_modify: true pdf:docinfo:created: 2026-07-07T12:08:27Z