Clear-sky temperature and water vapor retrievals utilizing collocated microwave and infrared hyperspectrometers
Bibliographic record
Abstract
Accurately monitoring atmospheric temperature and water vapor profiles with high spatial and temporal resolutions is crucial for weather forecasting and climate research. Hyperspectral radiance measurements offer a promising opportunity to retrieve these profiles due to the distinct absorption features of various atmospheric compositions.Three clear-sky field campaigns were conducted in Ottawa to collect collocated hyperspectral measurements from two sophisticated instruments: the High Spectral Resolution Airborne Microwave Sounder (HiSRAMS) and the Atmospheric Emitted Radiance Interferometer (AERI). HiSRAMS operates within the microwave oxygen band (49.6-58.3 GHz) and microwave water vapor band (175.9-184.6 GHz), while AERI operates in the infrared spectral range (520-1800 cm-1). Both instruments possess high spectral resolution, enabling the detection of subtle changes in temperature and water vapor profiles. Radiosonde measurements were simultaneously taken during each field campaign to serve as the truth for this study.Initially, we performed a simultaneous assessment of the radiometric accuracy of HiSRAMS and AERI through radiative closure tests. A persistent warm radiance bias was detected in AERI observations in the window band. Correcting this bias improved radiative closure within the same band. HiSRAMS observations, when directed towards the nadir, displayed a smaller brightness temperature bias compared to zenith observations. We diagnosed and compared the radiometric accuracy of both instruments based on the relationship between radiometric bias and optical depth. HiSRAMS exhibited similar radiometric accuracy to AERI in nadir-pointing measurements but demonstrated comparatively poorer accuracy in zenith-pointing measurements, necessitating further characterization.Subsequently, clear-sky temperature and water vapor concentration profiles were successfully retrieved from collocated HiSRAMS flight measurements and AERI ground measurements. These retrieved profiles were validated against radiosonde measurements, demonstrating good agreement. When both instruments were positioned on the ground for zenith-pointing measurements, infrared hyperspectral measurements provided higher information content and better vertical resolution for temperature and water vapor retrievals compared to microwave hyperspectral measurements. Combining airborne nadir-pointing microwave measurements and ground-based zenith-pointing infrared measurements, termed the “sandwich” sounding approach, exhibited increased information content and reduced retrieval uncertainty for temperature and water vapor concentrations across all retrieval levels.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".