O produto da versão noturna 1 (VNP21A1N) de temperatura e emissividade da superfície terrestre (LST&E) do Visible Infrared Imaging Radiometer Suite (VIIRS) da NASA Suomi National Polar-Orbiting Partnership (Suomi NPP) é compilado diariamente com base em produtos intermediários em grade de nível 2 (L2G) noturnos.
O processo L2G mapeia os grânulos de faixa diária do VNP21 em uma grade sinusoidal do MODIS e armazena todas as observações que se sobrepõem a uma célula em grade para uma determinada noite. O algoritmo VNP21A1 classifica todas essas observações para cada célula e estima o valor final de LST como uma média de todas as observações sem nuvens que têm boas precisões de LST. Somente observações com cobertura maior que um determinado limite (15%) são consideradas para essa média.
Controle de qualidade diário para LST e emissividade
Máscara de bits para QC
Bits 0-1: flags obrigatórias de controle de qualidade
0: Pixel produzido, boa qualidade, não são necessárias mais informações de QA
1: Pixel produzido, mas com qualidade não confiável
2: Pixel não produzido devido à nuvem
3: O Pixel não foi produzido por motivos diferentes da nuvem
Bits 2 a 3: flag de qualidade dos dados
0: boa qualidade dos dados das bandas L1B 14, 15 e 16
1: pixel ausente
2: Calibragem razoável
3: Calibragem ruim, processamento do TES ignorado
Bits 4 a 5: flag de nuvem
0: sem nuvens
1: cirro fino
2: Pixel a 2 pixels da nuvem mais próxima
3: pixels nublados
Bits 6 a 7: iterações
0: Convergência lenta
1: Nominal
2: Nominal
3: rápida
Bits 8-9: opacidade atmosférica
0: ≥3 (ar quente e úmido ou terra fria)
1: 0,2 - 0,3 (valor nominal)
2: 0,1 - 0,2 (valor nominal)
3: <0, 1 (pixel seco ou de alta altitude)
Bits 10-11: MMD
0: >0,15 (a maioria das rochas de silicato)
1: 0,1 a 0,15 (rochas, areia, alguns solos)
2: 0,03 a 0,1 (principalmente solos, pixel misto)
3: <0,03 (vegetação, neve, água, gelo, alguns solos)
Bits 12-13: acurácia de emissividade
0: >0,02 (desempenho ruim)
1: 0,015 a 0,02 (desempenho marginal)
2: 0,01 a 0,015 (boa performance)
3: <0,01 (excelente performance)
Bits 14-15: acurácia de LST
0: >2K (desempenho ruim)
1: 1,5 a 2 mil (desempenho marginal)
2: 1 a 1,5 mil (boa performance)
3: <1K (Excelente performance)
Emis_14
metros
Emissividade diária do M14
Emis_15
metros
Emissividade diária de M15
Emis_16
metros
Emissividade diária do M16
View_Angle
graus
metros
Ver o ângulo zenital de LST
View_Time
h
metros
Horário da observação de LST
Termos de Uso
Termos de Uso
Os dados da NASA do LP DAAC são de livre acesso. No entanto, quando um autor publica esses dados ou trabalhos baseados neles, é necessário citar os conjuntos de dados no texto da publicação e incluir uma referência a eles na lista de referências.
O produto da versão noturna 1 de temperatura e emissividade da superfície terrestre (LST&E, na sigla em inglês) do Visible Infrared Imaging Radiometer Suite (VIIRS) da Suomi National Polar-Orbiting Partnership (Suomi NPP) da NASA (VNP21A1N) é compilado diariamente com base em produtos intermediários de nível 2 (L2G) em grade noturnos. O processo L2G mapeia os grânulos de faixa diários do VNP21 em uma grade sinusoidal do MODIS…
[null,null,[],[[["\u003cp\u003eThe NASA VIIRS VNP21A1N dataset provides daily nighttime land surface temperature and emissivity data at a 1km resolution.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset is derived from the Suomi NPP satellite and covers the period from January 19, 2012, to December 10, 2024.\u003c/p\u003e\n"],["\u003cp\u003eLand surface temperature is estimated by averaging cloud-free observations with good LST accuracies, using only observations with coverage greater than 15%.\u003c/p\u003e\n"],["\u003cp\u003eAlongside temperature, the dataset includes quality control information, emissivity bands, view angle, and view time.\u003c/p\u003e\n"],["\u003cp\u003eUsers are requested to cite the dataset and associated documentation when publishing results based on this data.\u003c/p\u003e\n"]]],[],null,["Dataset Availability\n: 2012-01-19T00:00:00Z--2025-08-30T00:00:00Z\n\nDataset Provider\n:\n\n\n [NASA LP DAAC at the USGS EROS Center](https://doi.org/10.5067/VIIRS/VNP21A1N.002)\n\nCadence\n: 1 Day\n\nTags\n:\n[climate](/earth-engine/datasets/tags/climate) [daily](/earth-engine/datasets/tags/daily) [land](/earth-engine/datasets/tags/land) [nasa](/earth-engine/datasets/tags/nasa) [night](/earth-engine/datasets/tags/night) [noaa](/earth-engine/datasets/tags/noaa) [surface](/earth-engine/datasets/tags/surface) [temperature](/earth-engine/datasets/tags/temperature) [viirs](/earth-engine/datasets/tags/viirs) \n\nDescription \nThe NASA Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible\nInfrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and\nEmissivity (LST\\&E) Night Version 1 product (VNP21A1N) is compiled daily\nfrom nighttime Level 2 Gridded (L2G) intermediate products.\n\nThe L2G process maps the daily VNP21 swath granules onto a sinusoidal MODIS\ngrid and stores all observations overlapping a gridded cell for a given\nnight. The VNP21A1 algorithm sorts through all these observations for each\ncell and estimates the final LST value as an average from all cloud-free\nobservations that have good LST accuracies. Only observations having\nobservation coverage more than a certain threshold (15%) are considered for\nthis averaging.\n\nDocumentation:\n\n- [User's Guide](https://lpdaac.usgs.gov/documents/429/VNP21_User_Guide_V1.pdf)\n\n- [Algorithm Theoretical Basis Document (ATBD)](https://lpdaac.usgs.gov/documents/1332/VNP21_ATBD_V1.pdf)\n\n- [General Documentation](https://lpdaac.usgs.gov/products/vnp21a1nv002/)\n\n- [Land Product Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/browse?sensor=VIIRS&sat=SNPP)\n\nBands\n\n\n**Pixel Size**\n\n1000 meters\n\n**Bands**\n\n| Name | Units | Pixel Size | Description |\n|--------------|-------|------------|----------------------------------------------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|\n| `LST_1KM` | K | meters | Daily 1 km Land Surface Temperature. |\n| `QC` | | meters | Daily Quality control for LST and emissivity |\n| Bitmask for QC - Bits 0-1: Mandatory QA flags - 0: Pixel produced, good quality, no further QA info necessary - 1: Pixel produced but unreliable quality - 2: Pixel not produced due to cloud - 3: Pixel not produced due to reasons other than cloud - Bits 2-3: Data quality flag - 0: Good data quality of L1B bands 14, 15, 16 - 1: Missing pixel - 2: Fairly calibrated - 3: Poorly calibrated, TES processing skipped - Bits 4-5: Cloud Flag - 0: Cloud-free - 1: Thin cirrus - 2: Pixel within 2 pixels of nearest cloud - 3: Cloudy pixels - Bits 6-7: Iterations - 0: Slow convergence - 1: Nominal - 2: Nominal - 3: Fast - Bits 8-9: Atmospheric Opacity - 0: ≥3 (Warm, humid air; or cold land) - 1: 0.2 - 0.3 (Nominal value) - 2: 0.1 - 0.2 (Nominal value) - 3: \\\u003c0.1 (Dry, or high altitude pixel) - Bits 10-11: MMD - 0: \\\u003e0.15 (Most silicate rocks) - 1: 0.1 - 0.15 (Rocks, sand, some soils) - 2: 0.03 - 0.1 (Mostly soils, mixed pixel) - 3: \\\u003c0.03 (Vegetation, snow, water, ice, some soils) - Bits 12-13: Emissivity accuracy - 0: \\\u003e0.02 (Poor performance) - 1: 0.015 - 0.02 (Marginal performance) - 2: 0.01 - 0.015 (Good performance) - 3: \\\u003c0.01 (Excellent performance) - Bits 14-15: LST accuracy - 0: \\\u003e2K (Poor performance) - 1: 1.5 - 2K (Marginal performance) - 2: 1 - 1.5K (Good performance) - 3: \\\u003c1K (Excellent performance) ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||\n| `Emis_14` | | meters | Daily M14 emissivity |\n| `Emis_15` | | meters | Daily M15 emissivity |\n| `Emis_16` | | meters | Daily M16 emissivity |\n| `View_Angle` | deg | meters | View zenith angle of LST |\n| `View_Time` | h | meters | Time of LST observation |\n\nTerms of Use\n\n**Terms of Use**\n\nLP DAAC NASA data are freely accessible; however, when an author\npublishes these data or works based on the data, it is requested that the\nauthor cite the datasets within the text of the publication and include a\nreference to them in the reference list.\n\nCitations \nCitations:\n\n- Please visit [LP DAAC 'Citing Our Data' page](https://lpdaac.usgs.gov/citing_our_data)\n for information on citing LP DAAC datasets.\n\nDOIs\n\n- \u003chttps://doi.org/10.5067/VIIRS/VNP21A1N.002\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 dataset = ee.ImageCollection('NASA/VIIRS/002/VNP21A1N')\n .filter(ee.Filter.date('2022-11-01', '2022-12-01'));\n\nvar visualization = {\n bands: ['LST_1KM'],\n min: [150],\n max: [300],\n palette: [\n 'a50026',\n 'd73027',\n 'f46d43',\n 'fdae61',\n 'fee08b',\n 'ffffbf',\n 'd9ef8b',\n 'a6d96a',\n '66bd63',\n '1a9850',\n '006837',\n ]\n};\nMap.setCenter(41.2, 38.84, 3);\nMap.addLayer(dataset, visualization, 'LST');\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/NASA/NASA_VIIRS_002_VNP21A1N) \n[VNP21A1N.002: Night Land Surface Temperature and Emissivity Daily 1km](/earth-engine/datasets/catalog/NASA_VIIRS_002_VNP21A1N) \nThe NASA Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and Emissivity (LST\\&E) Night Version 1 product (VNP21A1N) is compiled daily from nighttime Level 2 Gridded (L2G) intermediate products. The L2G process maps the daily VNP21 swath granules onto a sinusoidal MODIS grid ... \nNASA/VIIRS/002/VNP21A1N, climate,daily,land,nasa,night,noaa,surface,temperature,viirs \n2012-01-19T00:00:00Z/2025-08-30T00:00:00Z \n-90 -180 90 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [https://doi.org/10.5067/VIIRS/VNP21A1N.002](https://doi.org/https://doi.org/10.5067/VIIRS/VNP21A1N.002)\n- [https://doi.org/10.5067/VIIRS/VNP21A1N.002](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/NASA_VIIRS_002_VNP21A1N)"]]
