El conjunto de datos MYD21A1D se produce a diario a partir de productos intermedios de LST en formato de cuadrícula de nivel 2 (L2G) durante el día, con una resolución espacial de 1,000 metros. El proceso de L2G asigna los gránulos diarios de la franja de MOD21 a una cuadrícula sinusoidal de MODIS y almacena todas las observaciones que se encuentran sobre una celda de la cuadrícula para un día determinado. El algoritmo MOD21A1 clasifica estas observaciones para cada celda y estima el valor final del LST como un promedio de todas las observaciones que no tienen nubes y tienen buenas precisiones de LST y E. El promedio diurno se pondera según la cobertura de observación de esa celda. Solo se consideran las observaciones que tienen una cobertura de observación superior a un umbral del 15%. El producto MYD21A1D contiene el LST calculado, así como el control de calidad, las tres bandas de emisividad, el ángulo cenital de visualización y la hora de observación.
El conjunto de datos MYD21A1D se produce diariamente a partir de productos intermedios de LST en formato de cuadrícula de nivel 2 (L2G) diurnos con una resolución espacial de 1,000 metros. El proceso de L2G asigna los gránulos diarios de la franja MOD21 a una cuadrícula sinusoidal de MODIS y almacena todas las observaciones que se encuentran sobre una celda de la cuadrícula para un día determinado. El…
[null,null,[],[[["\u003cp\u003eMYD21A1D provides daily land surface temperature (LST) and emissivity data at a 1,000-meter resolution, derived from NASA's Aqua satellite.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset covers the globe and includes quality control flags for cloud cover, atmospheric conditions, and data accuracy.\u003c/p\u003e\n"],["\u003cp\u003eLST values are calculated as a weighted average of cloud-free observations within each grid cell.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset is freely available for use, sale, and redistribution through the LP DAAC.\u003c/p\u003e\n"],["\u003cp\u003eUsers can access and analyze MYD21A1D data using Google Earth Engine.\u003c/p\u003e\n"]]],["The MYD21A1D dataset, provided by NASA LP DAAC at the USGS EROS Center, contains daily land surface temperature (LST) and emissivity data from 2000-02-24 to 2025-02-20. Data is derived from MODIS observations, gridded to 1km resolution. The dataset calculates LST by averaging cloud-free observations with good accuracy, weighted by observation coverage. Available bands include LST, quality control, three emissivity bands, view zenith angle, and observation time. It is accessible through Google Earth Engine.\n"],null,["Dataset Availability\n: 2000-02-24T00:00:00Z--2025-08-27T00:00:00Z\n\nDataset Provider\n:\n\n\n [NASA LP DAAC at the USGS EROS Center](https://doi.org/10.5067/MODIS/MYD21A1D.061)\n\nCadence\n: 1 Day\n\nTags\n:\n[aqua](/earth-engine/datasets/tags/aqua) [climate](/earth-engine/datasets/tags/climate) [daily](/earth-engine/datasets/tags/daily) [emissivity](/earth-engine/datasets/tags/emissivity) [global](/earth-engine/datasets/tags/global) [lst](/earth-engine/datasets/tags/lst) [nasa](/earth-engine/datasets/tags/nasa) [surface-temperature](/earth-engine/datasets/tags/surface-temperature) [usgs](/earth-engine/datasets/tags/usgs) \n\nDescription \nThe MYD21A1D dataset is produced daily from daytime Level 2 Gridded (L2G)\nintermediate LST products at a spatial resolution of 1,000 meters. The L2G\nprocess maps the daily MOD21 swath granules onto a sinusoidal MODIS grid and\nstores all observations falling over a gridded cell for a given day. The\nMOD21A1 algorithm sorts through these observations for each cell and\nestimates the final LST value as an average from all observations that are\ncloud free and have good LST\\&E accuracies. The daytime average is weighted\nby the observation coverage for that cell. Only observations having an\nobservation coverage greater than a 15% threshold are considered. The\nMYD21A1D product contains the calculated LST as well as quality control, the\nthree emissivity bands, view zenith angle, and time of observation.\n\nDocumentation:\n\n- [User's Guide](https://lpdaac.usgs.gov/documents/1398/MOD21_User_Guide_V61.pdf)\n\n- [Algorithm Theoretical Basis Document (ATBD)](https://lpdaac.usgs.gov/documents/1399/MOD21_ATBD.pdf)\n\n- [General Documentation](https://ladsweb.modaps.eosdis.nasa.gov/filespec/MODIS/61/MYD21A1D)\n\nBands\n\n\n**Pixel Size**\n\n1000 meters\n\n**Bands**\n\n| Name | Units | Min | Max | Pixel Size | Description |\n|--------------|-------|------|-------|------------|---------------------------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|\n| `LST_1KM` | K | 7500 | 65535 | meters | Land Surface Temperature |\n| `QC` | | | | meters | Quality Control |\n| Bitmask for QC - Bits 0-1: Mandatory QA flags - 0: Pixel produced, good quality, no further QA info necessary - 1: Pixel produced, nominal 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 29, 31, 32 - 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 pixel - Bits 6-7: TES Iterations - 0: =7 (Slow convergence) - 1: 6 (Nominal) - 2: 5 (Nominal) - 3: \\\u003c5 (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: Min-Max Difference(MMD). Difference between minimum and maximum emissivity for bands 29, 31, 32 - 0: 0.15 (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) - Bits 12-13: Emissivity accuracy - 0: 0.02 (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: 2 K (Poor performance) - 1: 1.5 - 2 K (Marginal performance) - 2: 1 - 1.5 K (Good performance) - 3: \\\u003c1 K (Excellent performance) ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||\n| `Emis_29` | | 0 | 255 | meters | Band 29 emissivity |\n| `Emis_31` | | 1 | 255 | meters | Band 31 emissivity |\n| `Emis_32` | | 1 | 255 | meters | Band 32 emissivity |\n| `View_Angle` | deg | 0 | 130 | meters | MODIS view zenith angle |\n| `View_Time` | h | 0 | 240 | meters | Time of MODIS observation |\n\nTerms of Use\n\n**Terms of Use**\n\nMODIS data and products acquired through the LP DAAC\nhave no restrictions on subsequent use, sale, or redistribution.\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/MODIS/MYD21A1D.061\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('MODIS/061/MYD21A1D')\n .filter(ee.Filter.date('2018-01-01', '2018-05-01'));\nvar landSurfaceTemperature = dataset.select('LST_1KM');\nvar landSurfaceTemperatureVis = {\n min: 216.0,\n max: 348.0,\n palette: [\n '040274', '040281', '0502a3', '0502b8', '0502ce', '0502e6',\n '0602ff', '235cb1', '307ef3', '269db1', '30c8e2', '32d3ef',\n '3be285', '3ff38f', '86e26f', '3ae237', 'b5e22e', 'd6e21f',\n 'fff705', 'ffd611', 'ffb613', 'ff8b13', 'ff6e08', 'ff500d',\n 'ff0000', 'de0101', 'c21301', 'a71001', '911003'\n ],\n};\nMap.setCenter(6.746, 46.529, 2);\nMap.addLayer(\n landSurfaceTemperature, landSurfaceTemperatureVis,\n 'Land Surface Temperature');\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/MODIS/MODIS_061_MYD21A1D) \n[MYD21A1D.061 Aqua Land Surface Temperature and 3-Band Emissivity Daily Global 1km](/earth-engine/datasets/catalog/MODIS_061_MYD21A1D) \nThe MYD21A1D dataset is produced daily from daytime Level 2 Gridded (L2G) intermediate LST products at a spatial resolution of 1,000 meters. The L2G process maps the daily MOD21 swath granules onto a sinusoidal MODIS grid and stores all observations falling over a gridded cell for a given day. The ... \nMODIS/061/MYD21A1D, aqua,climate,daily,emissivity,global,lst,nasa,surface-temperature,usgs \n2000-02-24T00:00:00Z/2025-08-27T00:00:00Z \n-90 -180 90 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [https://doi.org/10.5067/MODIS/MYD21A1D.061](https://doi.org/https://doi.org/10.5067/MODIS/MYD21A1D.061)\n- [https://doi.org/10.5067/MODIS/MYD21A1D.061](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/MODIS_061_MYD21A1D)"]]
