Landsat 8 Land Surface Temperature (LST) Calculator
Your expert tool to calculate temperature using Landsat 8 data.
LST Calculator
Metadata Values
Results
LST vs. NDVI
This chart illustrates the relationship between Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI).
Variable Explanations
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Band 10 (DN) | Digital Number for Thermal Band | – | 20000 – 40000 |
| Band 4 (DN) | Digital Number for Red Band | – | 5000 – 25000 |
| Band 5 (DN) | Digital Number for NIR Band | – | 10000 – 30000 |
| BT | Brightness Temperature | °C | -20 – 50 |
| NDVI | Normalized Difference Vegetation Index | – | -1 – 1 |
| LSE | Land Surface Emissivity | – | 0.9 – 1.0 |
| LST | Land Surface Temperature | °C | -20 – 50 |
What is Land Surface Temperature (LST)?
Land Surface Temperature (LST) is the radiative skin temperature of the land surface. It’s a measure of how hot the Earth’s surface would feel to the touch. LST is a critical variable in environmental and climate studies, influencing weather patterns, the water cycle, and the energy balance of the planet. While often related, LST is distinct from air temperature, which is what weather forecasts typically report. LST can be significantly higher or lower than the air temperature depending on factors like solar radiation, land cover, and soil moisture.
Anyone involved in urban planning, agriculture, forestry, hydrology, and climate change research can benefit from understanding LST. For example, urban planners use LST to identify and mitigate urban heat islands, while farmers use it to monitor crop health and water stress. A common misconception is that LST is the same as air temperature. However, LST can be much more variable, changing rapidly with sunlight and surface conditions.
Land Surface Temperature Formula and Mathematical Explanation
Calculating Land Surface Temperature from Landsat 8 data involves a series of steps and formulas. Here’s a breakdown of the process:
- Top of Atmosphere (TOA) Spectral Radiance: The first step is to convert the digital numbers (DN) from the thermal band (Band 10) into spectral radiance.
L = ML * Qcal + ALWhere L is the TOA spectral radiance, ML is the radiance multiplicative scaling factor, Qcal is the Band 10 DN value, and AL is the radiance additive scaling factor.
- Brightness Temperature (BT): The spectral radiance is then converted to brightness temperature in Celsius.
BT = (K2 / (ln(K1 / L) + 1)) - 273.15Where BT is the brightness temperature, K1 and K2 are thermal conversion constants, and L is the TOA spectral radiance.
- Normalized Difference Vegetation Index (NDVI): NDVI is calculated to estimate the amount of vegetation, which affects emissivity.
NDVI = (Band 5 - Band 4) / (Band 5 + Band 4) - Proportion of Vegetation (Pv): This is derived from NDVI to further quantify vegetation cover.
Pv = ((NDVI - NDVI_min) / (NDVI_max - NDVI_min))^2 - Land Surface Emissivity (LSE): Emissivity is calculated based on the proportion of vegetation.
LSE = 0.004 * Pv + 0.986 - Land Surface Temperature (LST): Finally, LST is calculated by correcting the brightness temperature for emissivity.
LST = (BT / (1 + (0.00115 * BT / 1.4388) * ln(LSE)))
Practical Examples
Example 1: Urban Area
An urban area with low vegetation will have a low NDVI and consequently a lower emissivity. This leads to a higher calculated LST. For instance, a pixel over an asphalt parking lot might have a low NDVI, resulting in a high LST, contributing to the urban heat island effect.
Example 2: Forested Area
A dense forest will have a high NDVI and a higher emissivity. This results in a lower LST compared to a nearby urban area under the same weather conditions. The vegetation helps to cool the surface through evapotranspiration. Our calculate temperature using landsat 8 pdf calculator can help you explore these differences.
How to Use This Land Surface Temperature Calculator
To use this calculator, you’ll need data from a Landsat 8 image, which can be downloaded from the USGS EarthExplorer. The necessary values (Band 10, Band 4, and Band 5 DNs, as well as the metadata constants) can be found in the downloaded files. Enter these values into the calculator to get the Land Surface Temperature and intermediate values. This tool to calculate temperature using landsat 8 pdf is a powerful way to understand your local environment.
Key Factors That Affect Land Surface Temperature Results
- Land Cover: Urban areas, bare soil, and water bodies have different LSTs.
- Vegetation: The amount and health of vegetation significantly impact LST.
- Soil Moisture: Wet soils have lower LSTs than dry soils.
- Solar Radiation: The amount of sunlight directly affects LST.
- Topography: The slope and aspect of the land can influence LST.
- Season and Time of Day: LST varies throughout the day and year.
Frequently Asked Questions (FAQ)
What is the difference between Land Surface Temperature and air temperature?
LST is the temperature of the ground, while air temperature is the temperature of the air above the ground. LST can be much more variable.
Why is Land Surface Temperature important?
LST is a key indicator of the Earth’s energy balance and is used in a wide range of applications, from climate modeling to agriculture. Understanding how to calculate temperature using landsat 8 pdf can provide valuable insights.
What is Landsat 8?
Landsat 8 is a satellite that provides images of the Earth’s surface. It has several sensors that capture data in different wavelengths, which can be used to calculate LST and other environmental variables.
Where can I get Landsat 8 data?
You can download Landsat 8 data for free from the USGS EarthExplorer website.
What is NDVI?
NDVI stands for Normalized Difference Vegetation Index. It is a measure of the amount of live vegetation in an area.
What is Land Surface Emissivity?
Emissivity is the measure of an object’s ability to emit thermal energy. It is an important factor in calculating LST.
What are the limitations of this calculation?
The accuracy of the LST calculation depends on the quality of the input data and the accuracy of the metadata values. Atmospheric conditions can also affect the results. This calculator provides a good estimate but for highly accurate scientific research, more complex atmospheric correction models may be needed.
Can I calculate temperature using landsat 8 pdf for historical dates?
Yes, you can use historical Landsat 8 data to calculate LST for past dates. The satellite has been in operation since 2013.
Related Tools and Internal Resources
- Albedo Calculator: Calculate the albedo of a surface.
- Vegetation Index Calculator: Calculate various vegetation indices.
- Urban Heat Island Calculator: Analyze the urban heat island effect in your city.
- Drought Monitor: Track drought conditions in your region.
- Soil Moisture Calculator: Estimate soil moisture levels.
- Evapotranspiration Calculator: Calculate the rate of evapotranspiration.