Agriculture and controlled environments
Leaf Temperature
叶片温度
Leaf temperature is the temperature of a leaf surface or tissue at a stated measurement location and time.
- Abbreviations
- Tleaf
- Aliases
- canopy leaf temperature
QUANTITY, SYMBOL AND UNIT
Quantity / objectLeaf temperature
SymbolT_leaf
SI°Cdegree Celsius
SIKkelvin
Definition
Leaf temperature is the temperature of a leaf surface or tissue at a stated measurement location and time.
It can differ from surrounding air temperature because radiation, transpiration, convection and plant water status affect the leaf energy balance. That difference changes the saturation vapour pressure at the leaf and therefore the leaf-to-air vapour-pressure gradient.
Relations and distinctions
Leaf and air temperature
Air temperature is measured in the surrounding air; leaf temperature belongs to the plant surface and can be higher or lower under the same room condition.
Leaf temperature and VPD
Leaf temperature is an input to leaf-based VPD. It is not itself a measure of humidity or plant water stress.
Engineering meaning
- Use representative leaf temperature when a leaf-based VPD or transpiration interpretation is needed.
- Record light, airflow, crop layer, sensor field of view and time when comparing leaf-temperature measurements.
Common misconceptions
MisconceptionLeaf temperature is always equal to the dry-bulb temperature shown by the room sensor.
Accurate explanationRadiation, convection and transpiration can create a meaningful leaf-to-air temperature difference.
Application boundaries
- One infrared spot may not represent a complete canopy, especially with mixed leaves, structure and background in the field of view.
- Leaf temperature alone cannot prescribe irrigation, dehumidification capacity or a crop-safe VPD target.
Supporting sources
-
Food and Agriculture Organization of the United Nations / SRC-FAO-LEAF-TEMP-VPD
The Effects of Elevated CO2 and Temperature Change on Transpiration and Crop Water Use ↗
/ Sections discussing leaf temperature, vapour-pressure gradient and transpiration
Supports: Leaf temperature can differ from air temperature; The leaf-to-air vapour-pressure gradient depends on leaf temperature; Transpiration and energy balance affect leaf temperature
Maintenance record
Leaf Temperature
- Maintained by
- Yakeclimate Engineering Team
- Authoritative sources verified
- August 3, 2026
- Terminology checked
- August 3, 2026
- Last updated
- August 3, 2026
- Term ID
- EKS-HUM-086