MOD21A1N 데이터 세트는 1,000미터의 공간 해상도로 야간 레벨 2 그리드 (L2G) 중간 LST 제품에서 매일 생성됩니다. L2G 프로세스는 일일 MOD21 스와스 과립을 사인파 MODIS 그리드에 매핑하고 주어진 날짜의 그리드 셀에 속하는 모든 관측치를 저장합니다. MOD21A1 알고리즘은 각 셀에 대해 이러한 관측치를 분류하고 구름이 없고 LST&E 정확도가 우수한 모든 관측치의 평균으로 최종 LST 값을 추정합니다. 야간 평균은 해당 셀의 관측 범위에 따라 가중치가 부여됩니다. 관측 범위가 15% 기준점보다 큰 관측치만 고려됩니다. MOD21A1N 제품에는 계산된 LST와 품질 관리, 3개의 방사율 대역, 시야각, 관측 시간이 포함됩니다.
MOD21A1N 데이터 세트는 1,000m의 공간 해상도로 야간 레벨 2 그리드 (L2G) 중간 LST 제품에서 매일 생성됩니다. L2G 프로세스는 일일 MOD21 스와스 과립을 사인파 MODIS 그리드에 매핑하고 주어진 날짜의 그리드 셀에 속하는 모든 관측치를 저장합니다. …
[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)"]]
