Calculate Temperature Using Landsat 8 PDF

Professional TIRS Land Surface Temperature (LST) Correction Tool

Parameter	Band 10 (Typical)	Band 11 (Typical)	Description
Radiance Mult (ML)	0.0003342	0.0003342	Scaling factor for radiance conversion
Radiance Add (AL)	0.1	0.1	Offset factor for radiance conversion
K1 Constant	774.8853	480.8883	Thermal conversion constant (W/m²·sr·µm)
K2 Constant	1321.0789	1201.1442	Thermal conversion constant (Kelvin)

Note: Always verify constants from the specific metadata (MTL) file provided with your Landsat 8 image package.

What is Calculate Temperature Using Landsat 8 PDF?

The process to calculate temperature using landsat 8 pdf involves a series of physical and mathematical conversions to transform raw satellite data into meaningful environmental measurements. Landsat 8 carries the Thermal Infrared Sensor (TIRS), which captures Earth’s heat radiation in two specific spectral bands: Band 10 and Band 11.

Researchers, urban planners, and environmental scientists use this method to monitor urban heat islands, agricultural health, and volcanic activity. A common misconception is that the “Digital Number” (DN) directly represents temperature. In reality, the DN is just a raw data count that must be corrected for atmospheric effects and surface emissivity to calculate temperature using landsat 8 pdf correctly.

Calculate Temperature Using Landsat 8 PDF Formula and Mathematical Explanation

To accurately calculate temperature using landsat 8 pdf, you must follow these three critical steps:

Step 1: Top of Atmosphere (TOA) Radiance

First, we convert the Digital Number (DN) to spectral radiance (L_λ). The formula is:

L_λ = M_L * Q_cal + A_L

Step 2: Brightness Temperature (BT)

Next, we convert the radiance into Brightness Temperature (the temperature of a black body) in Kelvin:

BT = K₂ / ln( (K₁ / L_λ) + 1 )

Step 3: Land Surface Temperature (LST)

Finally, we adjust for the emissivity of the surface to find the true LST:

LST = BT / (1 + (λ * BT / ρ) * ln(ε))

Variable	Meaning	Unit	Typical Range
Qcal	Digital Number (DN)	Unitless	0 – 65,535
Lλ	Spectral Radiance	W/(m²·sr·µm)	0.1 – 22.0
BT	Brightness Temperature	Kelvin	200 – 350 K
ε	Emissivity	Fraction	0.92 – 0.99

Practical Examples (Real-World Use Cases)

Example 1: Urban Asphalt in Summer

Suppose you have a pixel in a downtown area with a DN of 42,000. Using standard Band 10 constants (ML=0.0003342, AL=0.1, K1=774.88, K2=1321.07) and an emissivity of 0.95 for asphalt:

• TOA Radiance: (0.0003342 * 42000) + 0.1 = 14.136
• BT (Kelvin): 1321.07 / ln(774.88 / 14.136 + 1) = 328.45 K
• LST (°C): Approx 56.4°C

This reveals the intense heat absorption of urban surfaces compared to surrounding rural areas.

Example 2: Forest Canopy Monitoring

For a dense forest with a DN of 32,000 and emissivity of 0.98:

• TOA Radiance: 10.794
• BT (Kelvin): 309.82 K
• LST (°C): Approx 37.1°C

How to Use This Calculate Temperature Using Landsat 8 PDF Calculator

1. Open the MTL file: Locate the text metadata file that came with your Landsat download.
2. Find Constants: Search for RADIANCE_MULT_BAND_10 and K1_CONSTANT_BAND_10.
3. Input DN: Use a GIS tool (like QGIS or ArcGIS) to find the DN value of the specific pixel you want to analyze.
4. Set Emissivity: Choose an appropriate value based on land cover (0.98 for vegetation, 0.92 for sand).
5. Analyze Results: The calculator instantly provides LST in Celsius.

Key Factors That Affect Calculate Temperature Using Landsat 8 PDF Results

• Atmospheric Conditions: Water vapor and aerosols can distort the thermal signal before it reaches the sensor.
• Sensor Calibration: Landsat 8 TIRS had “stray light” issues in the early mission phase; using the latest USGS-calibrated metadata is essential.
• Land Cover Type: Different materials emit heat differently. A forest at 30°C looks different to the sensor than water at 30°C.
• Band Choice: Band 10 is generally preferred over Band 11 due to lower calibration uncertainty in earlier collections.
• Time of Day: Landsat 8 is sun-synchronous, usually passing at ~10:00 AM local time, meaning it misses peak daily heat.
• Pixel Size: TIRS has a 100m resolution (resampled to 30m), meaning small objects like individual buildings are “averaged” with their surroundings.

Frequently Asked Questions (FAQ)

Why does the Landsat 8 PDF recommend Band 10 over Band 11?

Band 10 is considered more stable and has fewer issues with stray light compared to Band 11, though split-window algorithms use both for higher accuracy.

Can I use this for Landsat 7 or 9?

The math is similar, but the constants (K1, K2, ML, AL) are unique to each satellite’s sensor. Always check the specific MTL file.

What is a typical emissivity for water?

Clean water is very efficient at emitting thermal energy, usually assigned a value of 0.98 to 0.99.

Why is my temperature result over 100°C?

Verify your DN value. High DN values (near 65535) represent extreme heat. Also, check if your Radiance Additive and Multiplier are correct.

Is the Brightness Temperature the same as the ground temperature?

No. Brightness Temperature assumes the Earth is a perfect “black body.” LST correction accounts for the reality that surfaces are “grey bodies” with emissivity < 1.

Where can I find the Landsat 8 MTL file?

It is downloaded as a text file (ending in _MTL.txt) alongside your .TIF image files from USGS EarthExplorer.

What is the wavelength of Landsat 8 Band 10?

The central wavelength for Band 10 is approximately 10.8 micrometers (µm).

Does this calculator handle cloud cover?

No. Thermal sensors cannot see through clouds. Pixels with cloud cover will show the temperature of the cloud tops, which is much colder than the ground.

Related Tools and Internal Resources

• Satellite Data Analysis Pro – Advanced processing for multi-spectral imagery.
• NDVI Vegetation Index Calculator – Determine land cover health to estimate emissivity.
• Atmospheric Correction Guide – How to remove water vapor effects from satellite data.
• Urban Heat Island Modeler – Specific workflows for urban thermal studies.
• GIS Metadata Reader – Extract ML and AL values automatically from MTL files.
• Remote Sensing Formulas PDF – A collection of essential physics equations for Earth observation.