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.