Hygroscopicity and CCN Activity of Water‐Soluble Extracts From the Arctic Aerosols in Winter to Early Summer
Bibliographic record
Abstract
Abstract The hygroscopicity and cloud condensation nuclei (CCN) activity of water‐soluble extracts from Arctic lower tropospheric aerosols during winter to summer were investigated under sub‐ and super‐saturated conditions, with chemical composition and air mass origin. The κ values from the hygroscopic growth factor at 80%–90% relative humidity (κHTDMA) during winter, spring, and summer were 0.34 ± 0.06, 0.41 ± 0.05, and 0.25 ± 0.02, respectively, whereas those derived from CCN activation diameter at 0.29%–0.59% supersaturation (κCCNC) were 0.42 ± 0.03, 0.43 ± 0.05, and 0.34 ± 0.11, respectively. The hygroscopicity and CCN activity showed clear seasonal variations following changes in composition that are linked to natural, anthropogenic, and biogenic sources. During winter and spring, κ was high when highly hygroscopic components such as sea salts, sulfate, and highly‐oxidized/aged particles were dominant due to long‐range atmospheric transport and photochemical reactions. In contrast, κ was significantly lower in summer when water‐insoluble (22%) and water‐soluble organic matter (OM) (17%) were dominated with high biogenic activity associated with ice‐edge zones. The κCCNC and κHTDMA values agreed well within 8% and the surface tension agreed with that of pure water within 10%. The κ for OM (κOM) estimated from chemical composition during spring and summer was on average 0.04 ± 0.06 (up to ∼0.17). This result suggests that highly hygroscopic components such as sea salt and sulfate mainly controlled particle hygroscopicity and CCN activity in winter, but water‐soluble OM could also contribute in spring and summer.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".