MOD21A1N veri kümesi,gece saatlerinde 1.000 metre uzamsal çözünürlükte ara LST ürünleri olan 2. Seviye Izgara (L2G) ürünlerinden günlük olarak üretilir. L2G
işlemi, günlük MOD21 şerit granüllerini sinüs şeklinde bir MODIS ızgarasına eşler ve
belirli bir günde ızgaralı bir hücreye düşen tüm gözlemleri depolar. MOD21A1 algoritması, her hücre için bu gözlemleri sıralar ve bulutsuz olan ve iyi LST&E doğruluğuna sahip tüm gözlemlerin ortalaması olarak nihai LST değerini tahmin eder. Gece ortalaması, ilgili hücrenin gözlem kapsamına göre ağırlıklandırılır. Yalnızca% 15 eşiğinden daha yüksek gözlem kapsamına sahip gözlemler dikkate alınır. MOD21A1N ürünü, kalite kontrolünün yanı sıra hesaplanmış LST'yi, üç emisyon bandını, görüntüleme zenit açısını ve gözlem zamanını içerir.
0: Pixel tarafından üretilmiş, iyi kalitede, başka kalite kontrol bilgisi gerekmiyor
1: Pixel tarafından üretilmiş, nominal kalite.
2: Bulut nedeniyle Pixel üretilmedi
3: Pixel, bulut dışındaki nedenlerle üretilmedi
Bit 2-3: Veri kalitesi işareti
0: L1B bantları 29, 31, 32'nin iyi veri kalitesi
1: Eksik piksel
2: Oldukça iyi kalibre edilmiş
3: Kötü kalibre edilmiş, TES işleme atlandı
4-5. bitler: Bulut İşareti
0: Cloud ücretsiz
1: İnce sirüs
2: En yakın bulutun 2 piksel içindeki Pixel
3: Bulutlu piksel
6-7. bitler: TES İterasyonları
0:
=7 (Yavaş yakınsama)
1: 6 (Nominal)
2: 5 (Nominal)
3: <5 (Hızlı)
8-9. bitler: Atmosferik Opaklık
0:
=3 (Sıcak, nemli hava veya soğuk kara)
1: 0,2 - 0,3 (Nominal değer)
2: 0,1 - 0,2 (Nominal değer)
3: <0, 1 (Kuru veya yüksek rakımlı piksel)
10-11. bitler: Min-Maks Farkı(MMD). 29, 31, 32 bantları için minimum ve maksimum emisyon arasındaki fark
0: 0,15 (Çoğu silikat kayası)
1: 0,1 - 0,15 (Kayalar, kum, bazı topraklar)
2: 0,03 - 0,1 (Çoğunlukla toprak, karışık piksel)
3: <0,03 (Bitki örtüsü, kar, su, buz)
Bit 12-13: Emisyon oranı doğruluğu
0:
0,02 (Düşük performans)
1: 0,015 - 0,02 (Sınırlı performans)
2: 0,01 - 0,015 (İyi performans)
3: <0,01 (Mükemmel performans)
14-15. bitler: LST doğruluğu
0:
2 K (Kötü performans)
1: 1,5 - 2 K (Marjinal performans)
2: 1 - 1,5 K (İyi performans)
3: <1 K (Mükemmel performans)
Emis_29
0
255
metre
29. bant emisyon oranı
Emis_31
1
255
metre
Bant 31 emisyon oranı
Emis_32
1
255
metre
32 bant emisyon oranı
View_Angle
drc
0
130
metre
MODIS görüntüleme zenit açısı
View_Time
sa.
0
240
metre
MODIS gözlem zamanı
Kullanım Şartları
Kullanım Şartları
LP DAAC aracılığıyla edinilen MODIS verileri ve ürünleri, sonraki kullanım, satış veya yeniden dağıtım açısından herhangi bir kısıtlamaya tabi değildir.
MOD21A1N veri kümesi,1.000 metre uzamsal çözünürlükte gece saatlerinde elde edilen 2. Seviye Kare Bölümlere Ayrılmış (L2G) ara LST ürünlerinden günlük olarak üretilir. L2G işlemi, günlük MOD21 şerit granüllerini sinüs şeklinde bir MODIS ızgarasına eşler ve belirli bir günde ızgaralı bir hücreye düşen tüm gözlemleri depolar. …
[null,null,[],[[["\u003cp\u003eMOD21A1N provides daily nighttime land surface temperature (LST) and emissivity data at a 1,000-meter resolution globally.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset is derived from MODIS Terra observations, averaging cloud-free, quality-assured LST measurements for each cell.\u003c/p\u003e\n"],["\u003cp\u003eIt includes quality control flags, emissivity bands, view zenith angle, and observation time for data validation and analysis.\u003c/p\u003e\n"],["\u003cp\u003eData is available from February 24, 2000, to December 10, 2024, and can be accessed through NASA's LP DAAC and Google Earth Engine.\u003c/p\u003e\n"],["\u003cp\u003eMODIS data and products acquired through the LP DAAC have no restrictions on subsequent use, sale, or redistribution.\u003c/p\u003e\n"]]],[],null,["Dataset Availability\n: 2000-02-24T00:00:00Z--2025-08-31T00:00:00Z\n\nDataset Provider\n:\n\n\n [NASA LP DAAC at the USGS EROS Center](https://doi.org/10.5067/MODIS/MOD21A1N.061)\n\nCadence\n: 1 Day\n\nTags\n:\n[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) [terra](/earth-engine/datasets/tags/terra) [usgs](/earth-engine/datasets/tags/usgs) \n\nDescription \nThe MOD21A1N 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\nMOD21A1N 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/MOD21A1N)\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/MOD21A1N.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/MOD21A1N')\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_MOD21A1N) \n[MOD21A1N.061 Terra Land Surface Temperature and 3-Band Emissivity Daily Global 1km](/earth-engine/datasets/catalog/MODIS_061_MOD21A1N) \nThe MOD21A1N 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/MOD21A1N, climate,daily,emissivity,global,lst,nasa,surface-temperature,terra,usgs \n2000-02-24T00:00:00Z/2025-08-31T00:00:00Z \n-90 -180 90 180 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [https://doi.org/10.5067/MODIS/MOD21A1N.061](https://doi.org/https://doi.org/10.5067/MODIS/MOD21A1N.061)\n- [https://doi.org/10.5067/MODIS/MOD21A1N.061](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/MODIS_061_MOD21A1N)"]]
