{
  "abstract": "Nocturnal cold-air pools can trap heat and pollutants in basin cities, but tropical basins are seldom monitored. We assessed deep surface-based night-time inversions over the Malang basin, East Java, Indonesia, from 2003–2025 MODIS Terra and Aqua night-time land surface temperature (LST), using the difference ΔT between a slope band (900–1300 m; mean 1079 m) and the rural basin floor (≤ 600 m; mean 449 m). Of 8395 nights, 2017 had sufficient clear-sky coverage. The slope band was colder than the floor on 98 % of clear nights (median ΔT −3.1 °C, against −4.1 °C for a standard atmosphere). ΔT > 0 occurred on 1.7 % of clear nights (35 nights; 95 % confidence interval 1.3–2.4 %) and on 1.3–2.2 % under a view-angle limit, removal of valley-floor pixels from the slope band and a fixed-pixel anomaly index, with median ΔT changing by less than 0.3 °C. Night-to-night variation in ΔT was not reproduced by the two overpasses about three hours apart (Spearman ρ = 0.05 on 351 shared nights), implying a per-overpass error of about 1 °C, as large as the night-to-night spread. A noise-only model accounts for the nights with ΔT > 0 observed by Terra alone or by both sensors, but not for those observed by Aqua alone (29 observed, 3–14 expected, a lower bound because the error estimate comes from the clearest nights), which include all 14 nights with ΔT > 1 °C. These nights were cloudy at ~22:30 and clear at ~01:30, wetter than average, and had an anomalously cold floor (median −4.5 °C) beneath near-normal slopes, consistent with post-rain cold pools, fog or residual cloud. After season adjustment, nights with ΔT > 0 were not calmer by ERA5-Land wind and only weakly wetter. Their frequency rose after 2015 in the Aqua record only. The night-time surface urban heat island was 0.9 °C and did not affect the result. At the MODIS overpass times and 1 km scale, slopes 630 m above the floor rarely out-warm it; MODIS LST constrains the climatology of this contrast but does not identify individual inversion nights.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "name": "Ryan Andri Wijaya"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/eqb7ga2e2s0yv.bib",
  "cited_by": 0,
  "doi": "10.31223/x5p222",
  "fulltext_url": null,
  "id": "eqb7ga2e2s0yv",
  "issns": [],
  "landing_url": "https://eartharxiv.org/repository/view/15346/",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/legalcode",
  "metadata_licence": null,
  "native_subjects": [
    [
      "bepress",
      "Atmospheric Sciences"
    ],
    [
      "bepress",
      "ERA5-Land"
    ],
    [
      "bepress",
      "Indonesia"
    ],
    [
      "bepress",
      "MODIS land surface temperature"
    ],
    [
      "bepress",
      "Meteorology"
    ],
    [
      "bepress",
      "cold-air pool"
    ],
    [
      "bepress",
      "retrieval uncertainty"
    ],
    [
      "bepress",
      "surface urban heat island"
    ],
    [
      "bepress",
      "temperature inversion"
    ],
    [
      "openalex",
      "2305|Urban Heat Island Mitigation"
    ]
  ],
  "openalex": "W7218644857",
  "pdf_url": "https://eartharxiv.org/repository/object/15346/download/26603/",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-03",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/eqb7ga2e2s0yv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:42Z",
      "native_id": "15346",
      "source": "eartharxiv",
      "url": "https://eartharxiv.org/repository/view/15346/"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "bepress:Atmospheric Sciences",
      "subfield": "atmospheric"
    }
  ],
  "title": "Slopes rarely out-warm the floor a 2003–2025 MODIS assessment of deep surface-based night-time inversions over the Malang basin, East Java",
  "title_text": "Slopes rarely out-warm the floor a 2003–2025 MODIS assessment of deep surface-based night-time inversions over the Malang basin, East Java",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:42Z",
  "url": "https://research.draconitic.com/paper/eqb7ga2e2s0yv",
  "venue": "EarthArXiv",
  "versions": []
}