Das Dataset MYD21A1N wird täglich aus LST-Zwischenprodukten (Level 2 Gridded,L2G) für die Nacht mit einer räumlichen Auflösung von 1.000 Metern erstellt. Im L2G-Prozess werden die täglichen MOD21-Swath-Granulen auf ein sinusförmiges MODIS-Raster abgebildet und alle Beobachtungen, die an einem bestimmten Tag in eine Rasterzelle fallen, werden gespeichert. Der MOD21A1-Algorithmus sortiert diese Beobachtungen für jede Zelle und schätzt den endgültigen LST-Wert als Durchschnitt aller Beobachtungen, die wolkenfrei sind und eine gute LST&E-Genauigkeit aufweisen. Der Durchschnitt für die Nacht wird nach der Beobachtungsabdeckung für diese Zelle gewichtet. Es werden nur Beobachtungen mit einer Beobachtungsabdeckung über einem Grenzwert von 15% berücksichtigt. Das Produkt MYD21A1N enthält die berechnete LST sowie die Qualitätskontrolle, die drei Emissivitätsbänder, den Zenitwinkel und die Beobachtungszeit.
2. Pixel innerhalb von 2 Pixeln der nächsten Wolke
3: Bewölktes Pixel
Bits 6–7: TES-Iteration
0:
=7 (langsame Konvergenz)
1: 6 (nominal)
2: 5 (nominal)
3: <5 (schnell)
Bits 8–9: Atmosphärische Trübung
0:
=3 (warme, feuchte Luft oder kaltes Land)
1: 0,2–0,3 (Nominalwert)
2: 0,1–0,2 (Nominalwert)
3: <0, 1 (trocken oder Pixel in großer Höhe)
Bits 10–11: Min-Max-Differenz(MMD). Differenz zwischen minimaler und maximaler Emissivität für die Bänder 29, 31 und 32
0: 0,15 (Die meisten Silikatgesteine)
1: 0,1–0,15 (Felsen, Sand, einige Böden)
2: 0,03–0,1 (hauptsächlich Böden, Mischpixel)
3: <0,03 (Vegetation, Schnee, Wasser, Eis)
Bits 12–13: Emissionsgradgenauigkeit
0:
0,02 (schlechte Leistung)
1: 0,015–0,02 (grenzwertige Leistung)
2: 0,01–0,015 (gute Leistung)
3: <0,01 (hervorragende Leistung)
Bits 14–15: LST-Genauigkeit
0:
2 K (schlechte Leistung)
1: 1,5–2 K (grenzwertige Leistung)
2: 1–1,5 K (gute Leistung)
3: <1.000 (hervorragende Leistung)
Emis_29
0
255
Meter
Emissivität von Band 29
Emis_31
1
255
Meter
Emissivität von Band 31
Emis_32
1
255
Meter
Emissivität von Band 32
View_Angle
Grad
0
130
Meter
MODIS-Zenitwinkel
View_Time
h
0
240
Meter
Zeit der MODIS-Beobachtung
Nutzungsbedingungen
Nutzungsbedingungen
Für MODIS-Daten und ‑Produkte, die über das LP DAAC bezogen werden, gelten keine Einschränkungen hinsichtlich der weiteren Verwendung, des Verkaufs oder der Weitergabe.
Das Dataset MYD21A1N wird täglich aus L2G-Zwischenprodukten (Level 2 Gridded) für die nächtliche LST mit einer räumlichen Auflösung von 1.000 Metern erstellt. Beim L2G-Prozess werden die täglichen MOD21-Swath-Granulen auf ein sinusförmiges MODIS-Raster abgebildet und alle Beobachtungen, die an einem bestimmten Tag in eine Rasterzelle fallen, werden gespeichert. Die …
[null,null,[],[[["\u003cp\u003eMYD21A1N provides daily nighttime land surface temperature (LST) and emissivity data at a 1,000 meter resolution, derived from the MODIS sensor on the Aqua satellite.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset includes quality control information, view zenith angle, and observation time, allowing for detailed analysis and filtering.\u003c/p\u003e\n"],["\u003cp\u003eLST values are estimated as an average from cloud-free observations with good accuracies, weighted by observation coverage.\u003c/p\u003e\n"],["\u003cp\u003eData is available from 2000-02-24 to 2024-12-10 and is freely accessible for use, sale, and redistribution through the LP DAAC.\u003c/p\u003e\n"],["\u003cp\u003eUsers can explore and analyze the dataset using Google Earth Engine, with code examples and documentation provided.\u003c/p\u003e\n"]]],[],null,["Dataset Availability\n: 2000-02-24T00:00:00Z--2025-09-05T00:00:00Z\n\nDataset Provider\n:\n\n\n [NASA LP DAAC at the USGS EROS Center](https://doi.org/10.5067/MODIS/MYD21A1N.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 MYD21A1N dataset is produced daily from nighttime 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 nighttime average is weighted\nby the observation coverage for that cell. Only observations having an\nobservation coverage greater than a 15% threshold are considered. The\nMYD21A1N 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/MYD21A1N)\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/MYD21A1N.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/MYD21A1N')\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_MYD21A1N) \n[MYD21A1N.061 Aqua Land Surface Temperature and 3-Band Emissivity Daily Global 1km](/earth-engine/datasets/catalog/MODIS_061_MYD21A1N) \nThe MYD21A1N dataset is produced daily from nighttime 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/MYD21A1N, aqua,climate,daily,emissivity,global,lst,nasa,surface-temperature,usgs \n2000-02-24T00:00:00Z/2025-09-05T00:00:00Z \n-90 -180 90 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [https://doi.org/10.5067/MODIS/MYD21A1N.061](https://doi.org/https://doi.org/10.5067/MODIS/MYD21A1N.061)\n- [https://doi.org/10.5067/MODIS/MYD21A1N.061](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/MODIS_061_MYD21A1N)"]]
