{"id":"3c72833b-90d4-4cf9-ae5f-6cfd099b234d","arxiv_id":"2606.17544","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"CST on Dopplergrams yields horizontal velocity fields with 73% global and 80% local correlation to CST on intensity images for 30-min averages.","lead":"This paper tests whether coherent structure tracking can extract solar surface horizontal flows from Dopplergrams as reliably as from intensity images. A generalist might read it to see if Doppler data alone can expand measurements of solar convection and flows.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.3","headline":"73% GCC between Doppler- and intensity-derived flows falls short of demonstrating equivalent confidence; contamination from vertical velocities remains unquantified.","rationale":"The reader's weakest assumption directly identifies the contamination risk; the reported 73% correlation supplies concrete evidence that this risk is material and has not been ruled out by the presented numbers.","tokens_in":1788,"tokens_out":310,"duration_ms":24692,"concrete_test":"For the 30-min averaged fields, compute the pixel-wise RMS difference between the Doppler-CST and intensity-CST velocity vectors; compare this RMS to the RMS difference obtained by applying CST to two independent 30-min intensity sequences separated by 15 min. If the Doppler-intensity RMS exceeds the temporal-variability RMS by more than 20%, the claim of equivalent confidence is not supported.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim requires that CST applied to Dopplergrams produces horizontal velocity fields whose reliability matches intensity-based CST. The abstract reports a global Pearson correlation of only 73% (30 min average) and 72% for divergence, with further reduction in active regions and for the curl component. These values indicate systematic differences whose origin (vertical-velocity contamination of the Doppler pattern, magnetic effects, or differing noise properties) is not isolated. Because the paper offers no independent error budget or comparison against a ground-truth flow (beyond the simulation case), the moderate correlation alone does not establish that the two pipelines can be used with equal confidence.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The manuscript applies the Coherent Structure Tracking (CST) technique to solar Dopplergrams from SDO/HMI and a numerical simulation of granulation, comparing the derived horizontal velocity fields and their derivatives (divergence and curl) to those obtained from continuum intensity images. It reports Pearson global correlation coefficients (GCC) of ~73% for velocity fields and ~72% for divergence over 30-minute averages (higher locally near disk center), with values increasing for longer averaging windows and slightly decreasing in more active regions, concluding that CST on Dopplergrams achieves comparable reliability.","tokens_in":1907,"tokens_out":517,"duration_ms":29198,"significance":"If the moderate correlations can be shown to arise from understood and correctable effects rather than fundamental limitations, the work would enable the use of Doppler data for high-resolution flow tracking, complementing intensity-based methods and potentially improving measurements in varied solar conditions. The inclusion of a numerical simulation validation, where high correlation is reported between intensity and vertical velocity maps, is a positive aspect demonstrating internal consistency in controlled conditions.","major_comments":[{"comment":"Abstract: The central claim that CST applied to Dopplergrams yields horizontal velocity fields 'with the same level of confidence' as intensity-based CST is not borne out by the reported GCC of 73% (30 min average) and 72% for divergence; these values imply ~27-28% unexplained variance, and the manuscript does not isolate or quantify contributions from vertical velocities contaminating the Doppler granulation pattern or from differing noise properties.","section":"Abstract"},{"comment":"Abstract: No error bars, uncertainty estimates, or details on data exclusion criteria (e.g., for magnetic regions or limb effects) are provided for the correlation coefficients, making it difficult to assess the statistical significance of the reported differences between active and quiet Sun or between components (velocity, divergence, curl).","section":"Abstract"}],"minor_comments":[{"comment":"The abstract refers to 'a relatively less active Sun' and 'magnetically more active Sun' without quantitative metrics such as average magnetic field strength or sunspot number for the selected periods.","section":null},{"comment":"Spearman's and Kendall's coefficients are mentioned as following a similar trend but no specific values are given, which would aid comparison to the Pearson results.","section":null}],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for their thoughtful comments on our manuscript. We address each major comment below and indicate where revisions will be made to improve clarity and provide additional statistical information.","responses":[{"response":"We acknowledge that the phrase 'same level of confidence' may overstate the case given the reported correlations of approximately 73%. We will revise the abstract to describe the results as achieving 'comparable reliability', aligning with the manuscript's conclusion section. The numerical simulation shows high correlation between CST on intensity and vertical velocity maps, supporting that the Doppler granulation pattern enables reliable horizontal flow tracking. While we do not provide a detailed decomposition of the unexplained variance into vertical velocity effects and noise, the overall correlations and the simulation validation indicate the method's viability. We will add a brief discussion of these potential sources in the revised text.","revision_made":"partial","referee_comment":"[Abstract] Abstract: The central claim that CST applied to Dopplergrams yields horizontal velocity fields 'with the same level of confidence' as intensity-based CST is not borne out by the reported GCC of 73% (30 min average) and 72% for divergence; these values imply ~27-28% unexplained variance, and the manuscript does not isolate or quantify contributions from vertical velocities contaminating the Doppler granulation pattern or from differing noise properties."},{"response":"We agree that including uncertainty estimates and details on data selection would strengthen the manuscript. In the revision, we will provide error bars on the correlation coefficients (e.g., using bootstrap methods or standard errors), specify the criteria used for excluding or masking magnetic regions, and discuss any considerations for limb effects in the data analysis.","revision_made":"yes","referee_comment":"[Abstract] Abstract: No error bars, uncertainty estimates, or details on data exclusion criteria (e.g., for magnetic regions or limb effects) are provided for the correlation coefficients, making it difficult to assess the statistical significance of the reported differences between active and quiet Sun or between components (velocity, divergence, curl)."}],"tokens_in":1499,"tokens_out":474,"duration_ms":35875,"standing_objections":["Complete isolation and quantitative decomposition of the contributions from vertical velocity contamination and noise properties to the ~27% unexplained variance in the correlations."]},"desk_editor":{"model":"grok-4.3","letter":"The main thing to know is that this paper quantifies CST applied to HMI Dopplergrams and finds Pearson correlations of 73% globally (80% locally near center) with the usual intensity-image results for 30-minute averages, rising with longer windows but dropping in active regions. The simulation case shows higher agreement, which is the cleanest part of the work.\n\nWhat is actually new is the direct side-by-side run on real solar data plus the simulation, with separate checks on divergence and curl. They report both global and local coefficients and note the trends with time averaging and magnetic activity. That empirical comparison had not been done at this level in the cited literature.\n\nThe soft spots sit in the strength of the central claim. 73% is only moderate agreement, and the paper offers no error budget, no isolation of vertical-velocity leakage into the Doppler pattern, and no independent ground-truth flows beyond the simulation. The curl component is noisier, as expected, and the match weakens where magnetic fields are present. These gaps make the \"same level of confidence\" phrasing hard to support from the numbers shown.\n\nThe paper is a narrow methods note for solar physicists who already use CST on intensity data and want to know whether Dopplergrams are a viable substitute. It is competent and the comparisons are reproducible from the data sources given, so it deserves a serious referee even though the interpretation needs tightening.","headline":"CST on Dopplergrams correlates at 73% globally with intensity-based flows, a useful check but not evidence they deliver the same reliability.","tokens_in":2340,"tokens_out":356,"would_cite":false,"duration_ms":22747,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"Coherent structure tracking applied to solar Dopplergrams yields horizontal velocity fields matching those from intensity images.","keywords":["coherent structure tracking","solar granulation","Dopplergrams","horizontal velocity fields","SDO/HMI","solar surface flows","granular proper motion"],"falsifier":"Finding global correlation coefficients below 50 percent between CST velocity fields from Dopplergrams and from intensity images on a new independent dataset or during a strongly magnetic period would falsify the claim of equivalent reliability.","tokens_in":2698,"feed_emoji":"☀️","tokens_out":675,"duration_ms":21343,"temperature":0.7,"pith_summary":"The paper tests whether Coherent Structure Tracking, which follows the motion of granules to map flows across the Sun's surface, works as reliably on Doppler velocity maps as on the usual continuum intensity images. By running CST on both types of data from SDO/HMI observations and from a numerical simulation of granulation, the authors measure global and local correlations between the resulting velocity fields, their divergence, and their curl. Correlations reach 73 percent globally and 80 percent locally near disk center for 30-minute averages on a quiet Sun, rising with longer averaging times and falling only modestly in more active regions. This opens an alternative data source for surface flow measurements since Dopplergrams are already collected routinely.","feed_headline":"Dopplergrams match intensity for solar flow tracking","feed_subtitle":"CST on Doppler maps gives 73 percent global correlation with intensity-derived velocity fields for 30-minute averages.","key_machinery":"Coherent Structure Tracking (CST), the method that follows proper motions of granular structures visible in images or maps to recover horizontal flow vectors.","core_discovery":"CST applied to Dopplergrams produces horizontal velocity fields whose Pearson global correlation coefficient with intensity-derived fields is about 73 percent for 30-minute averages, with local correlation near disk center at 80 percent for velocity and 84 percent for divergence. The same comparison on a numerical simulation of granulation shows high agreement, and the correlation coefficients improve steadily as the time window increases while decreasing slightly in regions containing sunspots or emerging pores.","pith_inferences":["Doppler-based CST could supply flow maps in spectral lines or instruments where continuum intensity granulation is weak or unavailable.","Combined Doppler and intensity CST might help isolate true horizontal motions from projection or vertical-velocity artifacts.","Routine use on Doppler data could support continuous surface-flow monitoring for studies of solar convection and magnetic flux transport."],"forward_implications":["Horizontal velocity fields from Doppler CST agree with intensity CST at 73 percent global correlation for 30-minute averages.","Divergence fields reach 72 percent global and 84 percent local correlation near disk center.","Correlation values rise as the averaging time window lengthens.","Agreement remains high but decreases modestly in the presence of sunspots or emerging pores.","CST on simulated intensity and vertical-velocity maps also produces closely matching horizontal flows."],"fun_headline_variants":["CST tracks solar flows on Dopplergrams with 73 percent global match","Dopplergram CST yields 80 percent local correlation near disk center","Correlation coefficients increase with longer CST time windows","Active regions reduce CST correlation slightly on solar Doppler maps","Simulation confirms high CST agreement between Doppler and intensity maps"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"Granulation patterns in Dopplergrams move in ways that directly reflect horizontal flows without large contamination from vertical velocities or magnetic effects.","fun_headline_variants_meta":{"raw":{"variants":["CST tracks solar flows on Dopplergrams with 73 percent global match","Dopplergram CST yields 80 percent local correlation near disk center","Correlation coefficients increase with longer CST time windows","Active regions reduce CST correlation slightly on solar Doppler maps","Simulation confirms high CST agreement between Doppler and intensity maps"]},"model":"grok-4.3","cost_usd":0.004875,"raw_usage":{"total_tokens":2442,"prompt_tokens":769,"num_sources_used":0,"completion_tokens":70,"cost_in_usd_ticks":48749500,"prompt_tokens_details":{"text_tokens":769,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":1603,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":769,"tokens_out":70,"duration_ms":15344,"temperature":1.0,"reasoning_tokens":1603,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-26T23:24:28.421828+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"Finding global correlation coefficients below 50 percent between CST velocity fields from Dopplergrams and from intensity images on a new independent dataset or during a strongly magnetic period would falsify the claim of equivalent reliability.","supporting_citations":[],"review_version":1}