MODIS Land Surface Temperature Download

Search and download MODIS LST products from NASA LAADS DAAC with Earthdata authentication.

Overview

MODIS Land Surface Temperature (LST) products provide per-pixel land surface temperature with 1km spatial resolution. This skill supports both Terra (MOD) and Aqua (MYD) satellite products at daily and 8-day composite intervals.

Products

Product	Satellite	Temporal	Resolution
MOD11A1	Terra	Daily	1km
MOD11A2	Terra	8-day	1km
MYD11A1	Aqua	Daily	1km
MYD11A2	Aqua	8-day	1km

Features

• Day and night LST: separate daytime and nighttime temperature layers
• Quality control: includes QC bands for quality filtering
• Search by date range and bbox: find available granules
• GeoTIFF output: standard georeferenced raster format
• Earthdata authentication: secure access to NASA data
• Fallback URL listing: shows download URLs even without credentials

Authentication

NASA Earthdata requires a free account. To configure:

1. Register at https://urs.earthdata.nasa.gov/
2. Set environment variables:

   export EARTHDATA_USERNAME="your_username"
   export EARTHDATA_PASSWORD="your_password"
   

3. Or use the configure command:

   python scripts\modis_lst_download.py configure --username your_username
   

Usage

# Search for available LST data
python scripts\modis_lst_download.py search \
  --product MOD11A1 \
  --start 2023-06-01 --end 2023-06-30 \
  --bbox 116.0 39.5 116.8 40.2

# Download daily LST (requires Earthdata auth)
python scripts\modis_lst_download.py download \
  --product MOD11A1 \
  --start 2023-07-01 --end 2023-07-01 \
  --bbox 116.0 39.5 116.8 40.2 \
  --output ./lst_data/ --layers LST_Day_1km,QC_Day

# Download 8-day composite
python scripts\modis_lst_download.py download \
  --product MOD11A2 \
  --start 2023-07-01 --end 2023-07-08 \
  --bbox 73 18 135 54 \
  --output ./china_lst/

# List download URLs without downloading
python scripts\modis_lst_download.py download \
  --product MYD11A1 \
  --start 2023-08-01 --end 2023-08-01 \
  --bbox 116.0 39.5 116.8 40.2 \
  --list-only

Parameters

• --product: MOD11A1, MOD11A2, MYD11A1, or MYD11A2
• --start/--end: Date range (YYYY-MM-DD)
• --bbox: Bounding box as west south east north
• --output: Output directory
• --layers: Comma-separated layer names (LST_Day_1km, LST_Night_1km, QC_Day, QC_Night)
• --list-only: Only list download URLs, do not download
• --username: Earthdata username (or set EARTHDATA_USERNAME env var)

Installation

# Install dependencies
pip install requests>=2.28.0 tqdm

# Or install from requirements.txt
pip install -r scripts/requirements.txt

Data Source

• API: NASA LAADS DAAC (https://ladsweb.modaps.eosdis.nasa.gov/)
• Search API: CMR (Common Metadata Repository) via CMR-STAC
• License: Public Domain (NASA open data)
• Rate Limit: No strict limit; recommended max 10 requests/minute
• CRS: Sinusoidal (MODIS native projection)
• Temporal coverage: Terra from 2000-02-24; Aqua from 2002-07-04
• Data latency: ~2 weeks for standard products

Product Citations

• MOD11A1: Wan, Z., S. Hook, and G. Hulley, 2015. MOD11A1 MODIS/Terra Land Surface Temperature/Emissivity Daily L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC.
• MOD11A2: Wan, Z., S. Hook, and G. Hulley, 2015. MOD11A2 MODIS/Terra Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC.
• MYD11A1: Wan, Z., S. Hook, and G. Hulley, 2015. MYD11A1 MODIS/Aqua Land Surface Temperature/Emissivity Daily L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC.
• MYD11A2: Wan, Z., S. Hook, and G. Hulley, 2015. MYD11A2 MODIS/Aqua Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC.

Citation Format

@misc{wan2015mod11a2,
  title={MOD11A2 MODIS/Terra Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006},
  author={Wan, Z. and Hook, S. and Hulley, G.},
  journal={NASA EOSDIS Land Processes DAAC},
  year={2015},
  doi={10.5067/MODIS/MOD11A2.006}
}

LST Scale Factor

• Raw values: Integer DN (Digital Number)
• Conversion: Multiply by 0.02 to get temperature in Kelvin
• To Celsius: T(°C) = DN × 0.02 - 273.15
• Example: DN 15000 → 300.00 K → 26.85°C

QC Band Interpretation

Bits	Field	Values
0-1	Quality flag	0=good quality, 1=other quality, 2=cloud contaminated, 3=not produced
2-3	Emissivity error flag	0=≤0.01, 1=≤0.02, 2=≤0.04, 3=>0.04
4-5	LST error flag	0=≤1K, 1=≤2K, 2=≤3K, 3=>3K

Cloud filtering: Keep only pixels where bits 0-1 = 0 (good quality).

8-Day Compositing Algorithm

MOD11A2 composites daily LST values over 8 days using:

• Cloud-free preference: Pixels with no cloud contamination are prioritized.
• Maximum temperature: For overlapping observations, the highest quality LST value is retained.
• QC-driven: Only pixels passing QC checks are included in the composite.

Visualization

• Temperature maps: Load GeoTIFF in QGIS with single-band pseudocolor, apply color ramp (blue→red).
• Time series: Stack multiple dates and plot with matplotlib.
• QC overlay: Use QC band to mask unreliable pixels before visualization.

Troubleshooting

Error	Cause	Solution
ConnectionError	Network issue or API down	Check internet connection, retry in 1 minute
HTTP 429	Rate limit exceeded	Wait 60 seconds before retrying
HTTP 404	Invalid parameters or date range	Check parameter names and date format
ValueError: bbox	Invalid bounding box	Ensure format is west,south,east,north
Empty output	No data for query region/time	Try different date range or check coordinates
ModuleNotFoundError	Missing dependency	Run pip install requests tqdm
401 Unauthorized	Earthdata auth failed	Check EARTHDATA_USERNAME/PASSWORD or run configure

---

Advanced Usage

Batch Time Series Download

# Download every month for a year
for month in $(seq -w 1 12); do
  python scripts\modis_lst_download.py download     --product MOD11A1 --bbox 116 39.5 117 40.2     --start 2023-${month}-01 --end 2023-${month}-28     --output lst_2023_${month}.tif
  sleep 2
done

CI/CD Integration (GitHub Actions)

# .github/workflows/update-modis-lst.yml
name: Update MODIS LST
on:
  schedule:
    - cron: '0 12 * * *'  # Daily
jobs:
  download:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.11'
      - run: pip install requests
      - env:
          EARTHDATA_USERNAME: ${{ secrets.EARTHDATA_USER }}
          EARTHDATA_PASSWORD: ${{ secrets.EARTHDATA_PASS }}
        run: |
          python scripts\modis_lst_download.py download \
            --product MOD11A1 --bbox 116 39.5 117 40.2 \
            --start $(date -d '3 days ago' +%Y-%m-%d) \
            --end $(date +%Y-%m-%d) \
            --output data/lst_latest.tif

LST Conversion & QC

import rasterio
import numpy as np
with rasterio.open('lst.tif') as src:
    raw = src.read(1)
    # Convert DN to Celsius: scale factor 0.02, offset 273.15
    lst_celsius = raw * 0.02 - 273.15
    # QC: use QC band bits 0-1, keep only value 0 (good quality)

PostgreSQL/PostGIS Raster Import

raster2pgsql -s 4326 -I -C lst.tif public.lst_raster | psql -d gis_db

Performance Tips

• Use --list-only first to preview URLs, then download in parallel
• Add sleep 2 between requests to avoid NASA rate limits
• For time series analysis, prefer MOD11A2 (8-day composite) over MOD11A1 to reduce cloud contamination

---

中文说明

从 NASA LAADS DAAC 搜索和下载 MODIS 地表温度（LST）产品。支持 Terra 和 Aqua 卫星的逐日和 8 天合成产品。

产品列表

产品	卫星	时间分辨率	空间分辨率
MOD11A1	Terra	逐日	1km
MOD11A2	Terra	8天合成	1km
MYD11A1	Aqua	逐日	1km
MYD11A2	Aqua	8天合成	1km

核心功能

• 昼夜地表温度：分别获取白天和夜间温度图层
• 质量控制：包含 QC 波段用于质量过滤
• 按日期范围和区域搜索：查找可用数据
• GeoTIFF 输出：标准地理参考栅格格式
• Earthdata 认证：安全访问 NASA 数据
• URL 列表回退：无认证时仍可列出下载链接

认证说明

NASA Earthdata 需要免费账号。配置方法：

1. 在 https://urs.earthdata.nasa.gov/ 注册
2. 设置环境变量：

   set EARTHDATA_USERNAME=your_username
   set EARTHDATA_PASSWORD=your_password
   

3. 或使用 configure 命令：

   python scripts\modis_lst_download.py configure --username your_username
   

使用示例

# 搜索可用 LST 数据
python scripts\modis_lst_download.py search \
  --product MOD11A1 \
  --start 2023-06-01 --end 2023-06-30 \
  --bbox 116.0 39.5 116.8 40.2

# 下载逐日 LST（需要 Earthdata 认证）
python scripts\modis_lst_download.py download \
  --product MOD11A1 \
  --start 2023-07-01 --end 2023-07-01 \
  --bbox 116.0 39.5 116.8 40.2 \
  --output ./lst_data/ --layers LST_Day_1km,QC_Day

# 下载 8 天合成产品
python scripts\modis_lst_download.py download \
  --product MOD11A2 \
  --start 2023-07-01 --end 2023-07-08 \
  --bbox 73 18 135 54 \
  --output ./china_lst/

# 仅列出下载 URL 不下载
python scripts\modis_lst_download.py download \
  --product MYD11A1 \
  --start 2023-08-01 --end 2023-08-01 \
  --bbox 116.0 39.5 116.8 40.2 \
  --list-only

数据来源

• API: NASA LAADS DAAC (https://ladsweb.modaps.eosdis.nasa.gov/)
• 搜索 API: CMR (Common Metadata Repository) via CMR-STAC
• 许可证: 公共领域（NASA 开放数据）
• 引用: Wan, Z., S. Hook, and G. Hulley, 2015. MOD11A2 MODIS/Terra Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V006. NASA EOSDIS Land Processes DAAC.