La collecte de données sur le formaldéhyde de niveau 3 fournit des informations sur les gaz à l'état de traces sur une grille régulière couvrant le champ d'observation TEMPO pour les observations TEMPO nominales. Les fichiers de niveau 3 sont obtenus en combinant les informations de tous les fichiers de niveau 2 constituant un cycle d'analyse TEMPO est-ouest. Les rasters contiennent des informations sur les colonnes verticales de formaldéhyde, les données auxiliaires utilisées dans les calculs du facteur de masse d'air et les corrections de secteur de référence ou de suppression des bandes, ainsi que les indicateurs de qualité de récupération.
L'algorithme de re-gridding utilise une approche pondérée par zone.
Une version de cet ensemble de données avec des filtres de qualité appliqués est disponible sous NASA/TEMPO/HCHO_L3_QA.
Somme des zones de chevauchement des pixels de niveau 2. Représente le facteur de pondération pour chaque cellule de la grille, indiquant la fraction de la zone de la cellule de la grille avec des données valides.
vertical_column
molécules/cm^2
mètres
Colonne verticale HCHO
vertical_column_uncertainty
molécules/cm^2
mètres
Incertitude de la colonne verticale de HCHO
main_data_quality_flag
Sans dimension
mètres
Indicateur principal de qualité des données. Fournit une évaluation globale de la qualité des données
num_vertical_column_samples
Sans dimension
mètres
Nombre d'échantillons de colonnes verticales
min_vertical_column_sample
molécules/cm^2
mètres
Exemple de colonne verticale la plus petite
max_vertical_column_sample
molécules/cm^2
mètres
Exemple de colonne verticale la plus grande
solar_zenith_angle
deg
mètres
Angle zénithal solaire au centre du pixel
viewing_zenith_angle
deg
mètres
Angle zénithal de vue au centre du pixel
relative_azimuth_angle
deg
mètres
Angle azimutal relatif au centre du pixel
surface_pressure
hPa
mètres
Pression de surface
terrain_height
m
mètres
Hauteur du terrain
snow_ice_fraction
Sans dimension
mètres
Fraction de la zone de pixels recouverte de neige et/ou de glace
fitted_slant_column
molécules/cm^2
mètres
Colonne inclinée ajustée HCHO
fitted_slant_column_uncertainty
molécules/cm^2
mètres
Incertitude de la colonne inclinée ajustée de HCHO
albedo
Sans dimension
mètres
Albédo de surface
amf
Sans dimension
mètres
Facteur de masse d'air HCHO
eff_cloud_fraction
Sans dimension
mètres
Fraction nuageuse effective
amf_cloud_fraction
Sans dimension
mètres
Fraction de rayonnement nuageux pour le calcul de l'AMF
NASA/LARC/SD/ASDC. (s.d.). TEMPO gridded HCHO vertical columns V03
(PROVISIONAL) [Ensemble de données]. NASA Langley
Atmospheric Science Data Center DAAC.
Extrait de https://doi.org/10.5067/IS-40e/TEMPO/HCHO_L3.003
La collecte de données de niveau 3 sur le formaldéhyde fournit des informations sur les gaz à l'état de traces sur une grille régulière couvrant le champ de vision de TEMPO pour les observations nominales de TEMPO. Les fichiers de niveau 3 sont obtenus en combinant les informations de tous les fichiers de niveau 2 constituant un cycle d'analyse TEMPO est-ouest. Les rasters contiennent des informations sur les colonnes verticales de formaldéhyde, les données auxiliaires…
[null,null,[],[],[],null,["Dataset Availability\n: 2023-08-01T00:00:00Z--2025-09-05T12:26:52Z\n\nDataset Provider\n:\n\n\n [NASA ASDC](https://asdc.larc.nasa.gov/)\n\nTags\n:\n[air-quality](/earth-engine/datasets/tags/air-quality) [formaldehyde](/earth-engine/datasets/tags/formaldehyde) [nasa](/earth-engine/datasets/tags/nasa) [pollution](/earth-engine/datasets/tags/pollution) [satellite-imagery](/earth-engine/datasets/tags/satellite-imagery) [tropomi](/earth-engine/datasets/tags/tropomi) \n\nDescription \nFormaldehyde Level 3 collection provides trace gas information on a\nregular grid covering the TEMPO field of regard for nominal TEMPO\nobservations. Level 3 files are derived by combining information from\nall Level 2 files constituting a TEMPO East-West scan cycle. The\nrasters contain information on formaldehyde vertical columns,\nancillary data used in air mass factor calculations and reference sector\nor de-striping corrections, and retrieval quality flags.\nThe re-gridding algorithm uses an area-weighted approach.\n\n- A version of this dataset with QA filters applied is available as [NASA/TEMPO/HCHO_L3_QA](/earth-engine/datasets/catalog/NASA_TEMPO_HCHO_L3_QA)\n- [General Documentation](https://asdc.larc.nasa.gov/documents/tempo/guide/TEMPO_Level-2-3_trace_gas_clouds_user_guide_V1.2.pdf)\n\nBands\n\n\n**Pixel Size**\n\n2226 meters\n\n**Bands**\n\n| Name | Units | Pixel Size | Description |\n|-----------------------------------|-----------------|------------|--------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `weight` | km\\^2 | meters | Sum of Level 2 pixel overlap areas. Represents the weighting factor for each grid cell, indicating the fraction of the grid cell area with valid data. |\n| `vertical_column` | molecules/cm\\^2 | meters | HCHO vertical column |\n| `vertical_column_uncertainty` | molecules/cm\\^2 | meters | HCHO vertical column uncertainty |\n| `main_data_quality_flag` | Dimensionless | meters | Main data quality flag. Provides an overall assessment of the data quality |\n| `num_vertical_column_samples` | Dimensionless | meters | Number of vertical column samples |\n| `min_vertical_column_sample` | molecules/cm\\^2 | meters | Smallest vertical column sample |\n| `max_vertical_column_sample` | molecules/cm\\^2 | meters | Largest vertical column sample |\n| `solar_zenith_angle` | deg | meters | Solar zenith angle at pixel center |\n| `viewing_zenith_angle` | deg | meters | Viewing zenith angle at pixel center |\n| `relative_azimuth_angle` | deg | meters | Relative azimuth angle at pixel center |\n| `surface_pressure` | hPa | meters | Surface pressure |\n| `terrain_height` | m | meters | Terrain height |\n| `snow_ice_fraction` | Dimensionless | meters | Fraction of pixel area covered by snow and/or ice |\n| `fitted_slant_column` | molecules/cm\\^2 | meters | HCHO fitted slant column |\n| `fitted_slant_column_uncertainty` | molecules/cm\\^2 | meters | HCHO fitted slant column uncertainty |\n| `albedo` | Dimensionless | meters | Surface albedo |\n| `amf` | Dimensionless | meters | HCHO air mass factor |\n| `eff_cloud_fraction` | Dimensionless | meters | Effective cloud fraction |\n| `amf_cloud_fraction` | Dimensionless | meters | Cloud radiance fraction for AMF calculation |\n| `amf_cloud_pressure` | hPa | meters | Cloud pressure for AMF calculation |\n\n**main_data_quality_flag Class Table**\n\n| Value | Color | Description |\n|-------|-------|-------------|\n| 0 | None | good |\n| 1 | None | suspect |\n| 2 | None | bad |\n\nTerms of Use\n\n**Terms of Use**\n\nThis dataset is in the public domain and is available\nwithout restriction on use and distribution. See [NASA's\nEarth Science Data \\& Information Policy](https://www.earthdata.nasa.gov/engage/open-data-services-and-software/data-and-information-policy)\nfor additional information.\n\nCitations \nCitations:\n\n- NASA/LARC/SD/ASDC. (n.d.). TEMPO gridded HCHO vertical columns V03\n (PROVISIONAL) \\[Data set\\]. NASA Langley\n Atmospheric Science Data Center DAAC.\n Retrieved from https://doi.org/10.5067/IS-40e/TEMPO/HCHO_L3.003\n\nDOIs\n\n- \u003chttps://doi.org/10.5067/IS-40e/TEMPO/HCHO_L3.003\u003e\n\nExplore with Earth Engine **Important:** Earth Engine is a platform for petabyte-scale scientific analysis and visualization of geospatial datasets, both for public benefit and for business and government users. Earth Engine is free to use for research, education, and nonprofit use. To get started, please [register for Earth Engine access.](https://console.cloud.google.com/earth-engine)\n\nCode Editor (JavaScript) \n\n```javascript\nvar collection = ee.ImageCollection('NASA/TEMPO/HCHO_L3')\n .filterDate('2024-04-01', '2024-04-05')\n\nvar visParams = {\n min: 0,\n max: 1.5e16,\n bands: ['vertical_column'],\n palette: [\n '000080', '0000D9', '4000FF', '8000FF', '0080FF',\n '00D9FF', '80FFFF', 'FF8080', 'D90000', '800000'\n ]\n};\nMap.setCenter(-95.06, 42.02, 3)\nMap.addLayer(collection, visParams, 'HCHO vertical column')\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/NASA/NASA_TEMPO_HCHO_L3) \n[TEMPO gridded HCHO vertical columns V03](/earth-engine/datasets/catalog/NASA_TEMPO_HCHO_L3) \nFormaldehyde Level 3 collection provides trace gas information on a regular grid covering the TEMPO field of regard for nominal TEMPO observations. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle. The rasters contain information on formaldehyde vertical columns, ancillary ... \nNASA/TEMPO/HCHO_L3, air-quality,formaldehyde,nasa,pollution,satellite-imagery,tropomi \n2023-08-01T00:00:00Z/2025-09-05T12:26:52Z \n-90 -180 90 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [https://doi.org/10.5067/IS-40e/TEMPO/HCHO_L3.003](https://doi.org/https://asdc.larc.nasa.gov/)\n- [https://doi.org/10.5067/IS-40e/TEMPO/HCHO_L3.003](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/NASA_TEMPO_HCHO_L3)"]]
