{"id":"c07db58b-0f7f-4bd7-b131-8f320d705378","arxiv_id":"2412.03586","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"A BBCEAS system with a spectrograph detects glyoxal at 10 ppt, while a cheaper rotating bandpass filter and photomultiplier detects it at 600 ppt.","lead":"This paper compares two ways to detect the trace gas glyoxal using cavity-enhanced absorption spectroscopy: a sensitive spectrograph and CCD setup, and a cheaper rotating bandpass filter with a photomultiplier tube. The spectrograph method reached 10 parts per trillion in one minute, while the cheaper method reached 600 parts per trillion in two minutes.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Off-band retrieval (Eq. 5) assumes zero methylglyoxal absorption at 458 nm, contradicting the paper's own §2.2 and §3.1.2; NO2 and CHOCHO concentrations are therefore biased.","rationale":"The central empirical claim is the detection limits for glyoxal by two detection schemes. The spectrograph/CCD result is plausible and supported by fit residuals, but the interferometer/PMT retrieval rests on Eq. (5) requiring a clean off-band window at 458 nm. The paper itself contradicts this: §2.2 says methylglyoxal affects the 453–458 nm window, and §3.1.2 estimates 1/30 of the interferometer CHOCHO signal could be methylglyoxal. This internal inconsistency is the most load-bearing concern because it directly biases the NO2 and CHOCHO retrievals used for the interferometer detection limit. However, the reader's CONDITIONAL verdict is appropriate: the paper acknowledges the interference, the effect is estimated as ~1/30, and the proof-of-concept status is not overthrown. No evidence of fraud or fabrication; the raw data link exists but lacks file-level identifiers. I recommend no change to the verdict.","tokens_in":17806,"tokens_out":2568,"duration_ms":21268,"concrete_test":"Use the methylglyoxal absorption cross-section from the cited Meller et al. (1991) reference, integrated over the off-band window (456.5–459.95 nm), and the methylglyoxal concentrations independently retrieved by the spectrograph/CCD in the same experiment, to recompute the NO2 and CHOCHO retrievals from Eqs. (4)–(6). If the CHOCHO concentrations shift by more than the paper's own 1/30 estimate (i.e., >3%) during the CHOCHO steps where methylglyoxal is present, the off-band assumption in Eq. (5) is quantitatively significant. Alternatively, add a known methylglyoxal standard to the cavity with zero glyoxal and check whether the interferometer reports a spurious glyoxal signal.","verdict_should_be":"UNCHANGED","load_bearing_attack":"Equation (5) (Section 2.3.2) retrieves NO2 from the 458 nm off-band extinction by asserting that both CHOCHO and methylglyoxal have zero absorption at that wavelength. This is internally contradicted: Section 2.2 states methylglyoxal 'impacts the 453–458 nm transmission window more substantially than the 457–459 nm window,' so the off-band window at 456.5–459.95 nm partially overlaps the 453–458 nm region, and Section 3.1.2 estimates that roughly 1/30 of the measured CHOCHO signal in the interferometer setup could be methylglyoxal. If methylglyoxal absorbs at 458 nm, the NO2 concentration from Eq. (5) is overestimated, and substituting that NO2 into Eq. (6) over-subtracts NO2 from the 455.5 nm extinction, biasing the CHOCHO retrieval. The paper states corrections 'can be applied' but Eq. (5) does not include the methylglyoxal term and no corrected retrieval is shown. This does not invalidate the proof-of-concept, but it makes the interferometer concentration scale conditional and the stated 600 ppt detection limit unverified in the presence of methylglyoxal.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper compares two detection schemes for broadband cavity-enhanced absorption spectroscopy (BBCEAS) of glyoxal: a spectrograph/CCD system, which spectrally fits CHOCHO, methylglyoxal, and NO2 over a broad wavelength range, and a rotating bandpass interferometer/PMT system, which alternates between an on-band (453.15–457.5 nm) and an off-band (456.5–459.95 nm) window and retrieves NO2 from the off-band extinction and CHOCHO from the on-band extinction after subtracting the NO2 contribution. The reported 1-minute 1-sigma detection limits for the spectrograph system are 10 ppt CHOCHO, 34 ppt methylglyoxal, and 22 ppt NO2; for the interferometer system the 2-minute 1-sigma detection limits are 600 ppt CHOCHO and 900 ppt NO2, with methylglyoxal below the detection limit. The authors frame the interferometer system as a proof-of-concept for a cost-effective, etalon-based on/off band detector coupled to a high-finesse cavity.","tokens_in":17955,"tokens_out":4668,"duration_ms":42182,"significance":"If the results hold, the paper provides a useful empirical comparison of two BBCEAS detector architectures and demonstrates that a simple rotating bandpass filter can extract glyoxal and NO2 concentrations with sub-ppb detection limits. The spectrograph/CCD detection limits are competitive with previous BBCEAS glyoxal instruments, and the interferometer approach is potentially cheaper and less data-intensive. The paper is explicitly a proof-of-concept, and the comparison of the two systems on the same gas stream is a valuable feature. The data availability statement and the use of literature absorption cross-sections are positive elements, though no analysis code is provided. The principal weaknesses are an internal inconsistency in the off-band assumption for methylglyoxal and the absence of a described detection-limit calculation, both of which affect the quantitative claims for the interferometer system.","major_comments":[{"comment":"Equation (5) assumes that at 458 nm both CHOCHO and methylglyoxal have zero absorption, so all off-band extinction is attributed to NO2. This contradicts the paper's own statements: §2.2 says methylglyoxal 'impacts the 453–458 nm transmission window more substantially than the 457–459 nm window,' and §3.1.2 estimates that roughly 1/30 of the interferometer CHOCHO signal could be attributed to methylglyoxal. Because the off-band window (456.5–459.95 nm) overlaps the 453–458 nm region, methylglyoxal absorption at 458 nm is not negligible. This would cause Eq. (5) to overestimate NO2, and since that NO2 is substituted into Eq. (6), the CHOCHO retrieval would be biased low. The paper mentions that corrections 'can be applied' but does not show a corrected retrieval or quantify the bias. The stated 600 ppt detection limit for the interferometer system is therefore not verified in the presence of methylglyoxal. I ask the authors to either include a methylglyoxal term in Eq. (5) (using the spectrograph-derived methylglyoxal concentrations) or to demonstrate quantitatively that the interference is negligible at 458 nm for the reported experiments.","section":"2.3.2, Eq. (5) and §2.2, §3.1.2"},{"comment":"The detection limits are central quantitative claims, but the paper never states how they are computed. For example, the 1-minute 1-sigma detection limit of 10 ppt for CHOCHO with the spectrograph and the 2-minute 1-sigma limit of 600 ppt with the interferometer are reported without defining whether they are the standard deviation of the retrieved concentration during zero-air sampling, an Allan deviation, the 3-sigma fit residual, or some other statistic. Without this information the results are not reproducible, and it is not clear whether the reported values are limits of detection in the usual sense or merely precision metrics. Please specify the exact calculation, the number of replicates or spectra used, and whether the interferometer limit accounts for the methylglyoxal interference discussed in the previous comment.","section":"3.1.1 and 3.1.2"},{"comment":"There are several ambiguities and apparent errors in the interferometer data-processing equations. Equation (4) includes a term [CHOCHO] σ_CHOCHO 485 nm, but the equation is written for 458 nm; the subscript '485 nm' appears to be a typo, and the term is dropped in Eq. (5) with the justification that CHOCHO has zero contribution at 458 nm. This is confusing. In addition, the text introducing Eq. (6) states that 'the NO2 concentration from the BBCEAS is substituted in,' which is ambiguous: it could refer to the NO2 retrieved from Eq. (5) using the interferometer's off-band data, or to the NO2 retrieved independently from the spectrograph. If the latter is intended, then the interferometer CHOCHO retrieval is not independent and the comparison in Figure 8 becomes partly circular. Please clarify the provenance of the NO2 concentration used in Eq. (6), and correct the wavelength subscripts consistently (455 nm vs. 455.5 nm).","section":"2.3.2, Eqs. (4) and (6)"},{"comment":"The paper does not provide an independent calibration or reference standard for the gas-phase glyoxal concentrations produced by the bubbler from the 40% w/w aqueous solution. The spectrograph retrievals rely entirely on literature absorption cross-sections, so the absolute concentration scale is not externally validated. This is acceptable for a proof-of-concept detection-limit study, but the inter-comparison between the two detectors in Figure 8 is then only a relative comparison. The authors should state this limitation explicitly and, if possible, quantify the expected uncertainty in the absolute concentration scale (e.g., from the purity of the commercial CHOCHO solution and the bubbler vapor pressure).","section":"Section 3.1.2"}],"minor_comments":[{"comment":"The caption reads 'interferometer/CCD data,' but the detector is a PMT, not a CCD; this should be corrected to 'interferometer/PMT data.'","section":"Figure 7 caption"},{"comment":"The text says the CHOCHO data are 'unprocessed' but then describes rolling-boxcar and two-minute-average smoothing; please rephrase to distinguish the raw PMT trace from the smoothed concentration traces.","section":"§3.1.2"},{"comment":"The statement that both interferometer bandpass positions (centered near 455.5 nm and 458 nm) fall within the water-vapor absorption bands of 440–450 nm and 466–476 nm appears inconsistent: 455.5 nm is outside the first band and 458 nm is outside both bands. Please check the wavelength ranges and clarify.","section":"§3.1.2"},{"comment":"The text contains a typo: 'CHOHCO' should be 'CHOCHO' in the sentence about compounds with sharp drops in absorption cross-sections.","section":"Conclusions"},{"comment":"Reference [21] states a slant column density of '6.23 × 1015 molecules·cm2'; the exponent on cm should presumably be −2. Please correct.","section":"Introduction"},{"comment":"Reference [1] is cited as a U.S. EPA substance registry entry for ethanedial; please confirm this is the appropriate source for the atmospheric-chemistry claim about glyoxal as a biogenic indicator, and consider citing a peer-reviewed review instead.","section":"References"}],"recommendation":"major_revision","confidential_remarks":"The spectrograph/CCD part of the paper is solid and the detection limits are competitive, but the novel interferometer retrieval has an internal inconsistency that affects the validity of the reported CHOCHO concentrations and the 600 ppt detection limit. The authors must fix Eq. (5) to account for methylglyoxal or demonstrate that its contribution at 458 nm is truly negligible for their gas stream. They also need to provide a precise description of how detection limits were calculated. These are fixable within the manuscript's scope, so I recommend major revision rather than rejection. I would also encourage the editor to verify that the data availability link is functional and contains the processed concentration time series, as the reproducibility of the central comparison depends on it."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Colleague,\n\nThis paper reports two things: a best-in-class BBCEAS glyoxal detection limit of 10 ppt (1 min, 1 sigma) with a spectrograph/CCD, and a proof-of-concept for replacing the spectrograph with a rotating bandpass filter (interferometer) and PMT. The 10 ppt number is a real improvement over the cited prior BBCEAS values of 19–30 ppt, and the head-to-head comparison of the two detectors is useful for anyone building low-cost field sensors. The etalon-based on/off band coupling is new in this cavity configuration, even if the rotating filter and dual-window ideas exist elsewhere.\n\nThe spectrograph results look credible. The fitted extinction residuals are low and unstructured, the concentration time series track the expected step changes, and the retrieval uses literature cross-sections plus a polynomial baseline with no other free parameters. That part is solid.\n\nThe soft spots are concentrated in the interferometer retrieval. Equation (5) retrieves NO2 from the 458 nm off-band extinction by asserting that glyoxal and methylglyoxal have zero absorption there. But Section 2.2 says methylglyoxal impacts the 453–458 nm transmission window, and Section 3.1.2 later estimates that roughly 1/30 of the measured CHOCHO signal could be methylglyoxal. That is an internal inconsistency. If methylglyoxal absorbs at 458 nm, the NO2 from Eq. (5) is biased high, and that propagates into the CHOCHO retrieval via Eq. (6). The paper says corrections can be applied, but no corrected retrieval is shown. For a proof-of-concept this is not fatal, but it means the interferometer concentration scale and the stated 600 ppt limit are conditional on the off-band window being clean. Also, the detection limit calculation method is not described at all—how the 1-sigma values were computed is unspecified. There is no independent calibration of the bubbler-generated glyoxal concentrations, and no raw data or code accompanies the paper; the data archive link lacks file-level identifiers.\n\nOverall, the central empirical comparison holds up. The spectrograph channel is well characterized, and the interferometer channel, despite the retrieval issue, trends correctly in the time series. The paper is honest about its limitations. Who is it for? People in atmospheric instrumentation and trace gas sensing, especially those thinking about cheap, field-deployable glyoxal monitors. It deserves a serious referee rather than desk rejection; the referee should focus on the retrieval inconsistency and the missing detection limit methodology.\n\nRecommendation: send it to peer review, with a request for clarification on the methylglyoxal interference and a proper description of the detection limit derivation.","headline":"A useful instrument comparison with a genuine 10 ppt spectrograph detection limit, but the interferometer retrieval has an unresolved methylglyoxal interference that makes its concentration scale conditional.","tokens_in":18581,"tokens_out":2064,"would_cite":false,"duration_ms":19406,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Broadband cavity-enhanced absorption spectroscopy read out by a spectrograph detects gas-phase glyoxal at 10 parts per trillion in one minute, while an interferometer-and-photomultiplier readout reaches 600 parts per trillion.","keywords":["glyoxal","broadband cavity-enhanced absorption spectroscopy","BBCEAS","interferometer","on-band/off-band detection","nitrogen dioxide","methylglyoxal","atmospheric trace gas detection"],"falsifier":"Flow a known concentration of pure methylglyoxal through the cavity while glyoxal is absent and $\\mathrm{NO_2}$ is held at a fixed, known level, then retrieve $\\mathrm{NO_2}$ from the off-band window centered at 458 nm: if the retrieved $\\mathrm{NO_2}$ exceeds the known value, methylglyoxal is absorbing off-band and the two-window retrieval is biased.","tokens_in":17543,"feed_emoji":"🔬","tokens_out":10437,"duration_ms":82437,"temperature":0.7,"pith_summary":"This paper is a proof-of-concept demonstration that a single high-finesse optical cavity can detect gas-phase glyoxal two ways: read out by a spectrograph plus CCD, or read out by a rotating bandpass interferometer plus photomultiplier tube. The spectrograph version achieves a 1 min $1\\sigma$ detection limit of $2.5\\times10^8$ molecules cm$^{-3}$ (10 ppt) for glyoxal, with methylglyoxal at 34 ppt and $\\mathrm{NO_2}$ at 22 ppt. The interferometer version, which is cheaper and produces far less data, achieves a 2 min $1\\sigma$ glyoxal detection limit of $1.5\\times10^{10}$ molecules cm$^{-3}$ (600 ppt) and an $\\mathrm{NO_2}$ limit of 900 ppt, with methylglyoxal below detection. The authors argue that the two-window on-band/off-band scheme is general enough to be pointed at other species with sharp absorption features. This matters because glyoxal is a marker for biogenic emissions and biomass burning, and a lower-cost field instrument would make such measurements more accessible.","feed_headline":"Glyoxal sensor reaches 10 ppt; cheaper readout hits 600 ppt","feed_subtitle":"A rotating filter and photomultiplier track ambient and biomass-burning glyoxal at a fraction of spectrograph cost.","key_machinery":"The load-bearing element is a 92.5 cm high-finesse cavity whose mirrors reach a reflectivity of 0.99985 at 455 nm, with the transmitted light split between two readouts. The spectrograph readout performs full spectral fitting of absorption cross-sections by nonlinear least squares. The interferometer readout uses a rotating bandpass filter, effectively a Fabry-Perot etalon, to alternate between an on-band window centered at 455.5 nm and an off-band window centered at 458 nm; a photomultiplier tube records each window's intensity. The off-band extinction is assigned entirely to $\\mathrm{NO_2}$ by $\\epsilon_{458} = [\\mathrm{NO_2}]\\,\\sigma_{\\mathrm{NO_2},458}$, and then the on-band equation $\\epsilon_{455.5} = [\\mathrm{CHOCHO}]\\,\\sigma_{\\mathrm{CHOCHO},455.5} + [\\mathrm{NO_2}]\\,\\sigma_{\\mathrm{NO_2},455.5}$ is solved for glyoxal.","core_discovery":"On the authors' own terms, the central discovery is that coupling a BBCEAS cavity to a rotating bandpass interferometer and photomultiplier can recover glyoxal concentrations from two spectral windows, one overlapping the glyoxal absorption band near 455.5 nm and one where glyoxal absorption is minimal near 458 nm, with the off-band window used to retrieve $\\mathrm{NO_2}$ and the on-band window then solved for glyoxal. The spectrograph/CCD channel achieves a 1 min $1\\sigma$ glyoxal detection limit of $2.5\\times10^8$ molecules cm$^{-3}$ (10 ppt); the interferometer/PMT channel achieves a 2 min $1\\sigma$ glyoxal detection limit of $1.5\\times10^{10}$ molecules cm$^{-3}$ (600 ppt) and an $\\mathrm{NO_2}$ limit of 900 ppt. The two-minute-averaged interferometer traces for glyoxal and $\\mathrm{NO_2}$ reproduce the trends seen with the spectrograph, which the authors take as evidence that the cheaper readout can track ambient glyoxal, while methylglyoxal remained below the interferometer's detection limit.","pith_inferences":["If a second photomultiplier were added so the on-band and off-band windows were read simultaneously, the square-wave duty cycle would disappear and the interferometer channel's time resolution would roughly double.","Because the paper estimates that about 1/30 of the interferometer glyoxal signal could be methylglyoxal, real wildfire-plume measurements would need a methylglyoxal correction or an additional window to avoid a systematic glyoxal overestimate.","The claim that the off-band window is clean at 458 nm can be tested directly by flowing pure methylglyoxal through the cavity; a nonzero extinction there would require replacing Equation (5) with a multi-species retrieval.","The noise sources the authors list for the interferometer channel (photon-counter readout, F-matching, and LED photon budget) are equipment choices, so the 600 ppt limit is probably an equipment floor rather than a fundamental one."],"forward_implications":["A spectrograph-based BBCEAS can push 1 min glyoxal detection down to 10 ppt, placing it at or below the detection limits reported for earlier LED-CE-DOAS and BBCEAS instruments.","The interferometer/PMT path, with a 2 min glyoxal limit of 600 ppt and an $\\mathrm{NO_2}$ limit of 900 ppt, is sufficient for ambient and biomass-burning plume measurements while avoiding the cost and data volume of a spectrograph.","Because the dual-window scheme subtracts extinction common to both windows, broadband absorbers such as aerosol can be treated as a direct intensity correction; the paper's simulated aerosol correction varies by less than 1% between the on-band and off-band windows.","Scanning more than two interferometer windows would allow low-resolution fitting of absorption cross-sections, which the authors suggest could aid species identification and reduce interferences.","The same on/off-band logic should transfer to other molecules with a sharp drop in absorption cross-section, such as formaldehyde, if the two windows are placed where only the target species absorbs."],"supporting_citations":[{"why":"Supplies the LED-CE-DOAS calibration approach, the Rayleigh-scattering reflectivity determination, and the $\\lambda^{-1.5}$ aerosol extinction scaling used in the dual-window correction.","marker":"[24]"},{"why":"Supplies the BBCEAS nonlinear least-squares fitting of absorption cross-sections and a prior glyoxal detection-limit benchmark the spectrograph channel builds on.","marker":"[26]"},{"why":"Justifies that an incoherent broadband source always couples some cavity modes and that transmitted light carries no mode structure, underpinning the cavity's stable operation.","marker":"[33]"},{"why":"Provides the incoherent broadband cavity-enhanced absorption spectroscopy data-processing framework the spectrometer channel follows.","marker":"[36]"},{"why":"Reports the earlier BBCEAS system whose reflectivity and extinction equations are reused in this instrument's processing.","marker":"[37]"},{"why":"Provides the high-resolution glyoxal absorption cross-sections used to fit and retrieve glyoxal concentrations.","marker":"[39]"},{"why":"Provides methylglyoxal absorption cross-sections used for its retrieval and for estimating its interference in the interferometer channel.","marker":"[40]"},{"why":"Provides the $\\mathrm{NO_2}$ visible absorption cross-sections used in both retrieval schemes.","marker":"[41]"},{"why":"Supplies the uncertainty estimates for glyoxal, methylglyoxal, and $\\mathrm{NO_2}$ cross-sections that set the error budget in the analysis.","marker":"[42]"},{"why":"Demonstrates dual-wavelength dual-cavity $\\mathrm{NO_2}$ detection in the presence of aerosol, supporting the two-window broadband-absorber cancellation logic.","marker":"[43]"}],"fun_headline_variants":["Glyoxal at 10 ppt via CCD, 600 ppt via interferometer","Cheaper glyoxal readout trades sensitivity: 600 ppt vs 10 ppt","Interferometer-based glyoxal sensor reaches 600 ppt, CCD hits 10","Two glyoxal detectors: spectrograph wins sensitivity, PMT wins cost"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The retrieval rests on the assumption that at 458 nm both glyoxal and methylglyoxal have exactly zero absorption, so all measured off-band extinction is $\\mathrm{NO_2}$; the paper's own discussion of methylglyoxal's influence on the 453-458 nm window and its estimate that about 1/30 of the interferometer glyoxal signal could be methylglyoxal show this assumption is not fully satisfied.","fun_headline_variants_meta":{"raw":{"variants":["Glyoxal at 10 ppt via CCD, 600 ppt via interferometer","Cheaper glyoxal readout trades sensitivity: 600 ppt vs 10 ppt","Interferometer-based glyoxal sensor reaches 600 ppt, CCD hits 10","Two glyoxal detectors: spectrograph wins sensitivity, PMT wins cost"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000265,"raw_usage":{"total_tokens":1699,"prompt_tokens":1127,"completion_tokens":572,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":743,"completion_tokens_details":{"reasoning_tokens":483}},"tokens_in":743,"tokens_out":572,"duration_ms":5583,"temperature":1.0,"reasoning_tokens":483,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T12:43:29.517514+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Flow a known concentration of pure methylglyoxal through the cavity while glyoxal is absent and $\\mathrm{NO_2}$ is held at a fixed, known level, then retrieve $\\mathrm{NO_2}$ from the off-band window centered at 458 nm: if the retrieved $\\mathrm{NO_2}$ exceeds the known value, methylglyoxal is absorbing off-band and the two-window retrieval is biased.","supporting_citations":[{"cited_title":"Inherent calibration of a blue LED-CE-DOAS instrument to measure iodine oxide, glyoxal, methyl glyoxal, nitrogen dioxide, water vapour and aerosol extinction in open cavity mode","cited_arxiv_id":null,"evidence_quote":"Supplies the LED-CE-DOAS calibration approach, the Rayleigh-scattering reflectivity determination, and the $\\lambda^{-1.5}$ aerosol extinction scaling used in the dual-window correction."},{"cited_title":"Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer","cited_arxiv_id":null,"evidence_quote":"Supplies the BBCEAS nonlinear least-squares fitting of absorption cross-sections and a prior glyoxal detection-limit benchmark the spectrograph channel builds on."},{"cited_title":"The superposition principle and cavity ring-down spectroscopy","cited_arxiv_id":null,"evidence_quote":"Justifies that an incoherent broadband source always couples some cavity modes and that transmitted light carries no mode structure, underpinning the cavity's stable operation."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Provides the incoherent broadband cavity-enhanced absorption spectroscopy data-processing framework the spectrometer channel follows."},{"cited_title":"Detection of Sulfur Dioxide by Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS)","cited_arxiv_id":null,"evidence_quote":"Reports the earlier BBCEAS system whose reflectivity and extinction equations are reused in this instrument's processing."},{"cited_title":"High-resolution absorption cross-section of glyoxal in the UV-vis and IR spectral ranges","cited_arxiv_id":null,"evidence_quote":"Provides the high-resolution glyoxal absorption cross-sections used to fit and retrieve glyoxal concentrations."},{"cited_title":"The UV-visible absorption-spectrum of methylglyoxal.J","cited_arxiv_id":null,"evidence_quote":"Provides methylglyoxal absorption cross-sections used for its retrieval and for estimating its interference in the interferometer channel."},{"cited_title":"High-resolution Fourier transform measurement of the NO 2 visible and near-infrared absorption cross sections: Temperature and pressure effects","cited_arxiv_id":null,"evidence_quote":"Provides the $\\mathrm{NO_2}$ visible absorption cross-sections used in both retrieval schemes."},{"cited_title":"Instrument intercomparison of glyoxal, methyl glyoxal and NO2 under simulated atmospheric conditions","cited_arxiv_id":null,"evidence_quote":"Supplies the uncertainty estimates for glyoxal, methylglyoxal, and $\\mathrm{NO_2}$ cross-sections that set the error budget in the analysis."},{"cited_title":"Dual-wavelength dual-cavity spectrometer for NO2 detection in the presence of aerosol interference","cited_arxiv_id":null,"evidence_quote":"Demonstrates dual-wavelength dual-cavity $\\mathrm{NO_2}$ detection in the presence of aerosol, supporting the two-window broadband-absorber cancellation logic."}],"review_version":1}