Microclimate at Harvard Forest HEM, LPH and EMS Towers since 2005

Microclimatic data are collected continuously within footprint areas of the flux
towers in order to (1) understand relationships between climatic and microclimatic
conditions and carbon dioxide and water vapor exchange between forest and atmosphere, (2)
to develop predictive models for the exchange rates of these gases, based on microclimate
data, (3) detect long-term trends in climate and microclimate at the sites and (4)
determine whether the response of carbon dioxide and water vapor exchange processes to
climate or microclimate is changing over time. The primary climatic and microclimatic
variables measured at these sites include: above-canopy photosynthetically active
radiation (PAR), forest understory PAR at 1 m height, total net radiation exchange
measured above the forest canopy, air temperature and relative humidity above the forest
canopy, forest understory air temperature at 20 cm and 1 m above ground level (shielded
but not ventilated thermocouple sensors, used only to estimate nighttime understory air
temperature), soil temperature at 10 cm depth, and soil moisture.