• Effects of clouds on carbon uptake by forests

      We have observed enhanced carbon uptake by trees on afternoons when cumulus clouds are present. We are exploring whether this effect is due to heat stress on those afternoons which are cloud-free, or whether some other reason explains this phenomenon.

• Phenology and Clouds

      Forests directly influence the atmosphere through the release of water vapor (transpiration). This water vapor may condense and form clouds. In this way, trees continually modify the environment. In particular, in deciduous forests in spring, there is a shift in the energy balance from a situation where most of the sun's energy is converted into heat, to one where water vapor release is more important. This effect is detectable in the climatic record.

• Multispectral Reflectance Measurements

      The amount of light reflected by forests varies by wavelength of light. The reflectance in certain wavelengths is partly determined by the physiological state of the trees. We are measuring the reflected light in several wavebands at Harvard forest in order to determine if data from satellites (which also measure reflected light) can be used to detect subtle changes in forest function.

• Water Balance of Forests

      We are studying the amount of total water vapor given off by trees in a forest compared to that which comes directly from the soil, or from under story plants. We are interested in the factors which determine how much water is given off, and how much carbon is taken up for a given amount of water given off.

• Energy Exchange in Curing Concrete

      In cooperation with the state Department of Transportation, and Dr. Richard Plawsky of RPI, we are studying the factors that influence the curing of concrete in bridges, and the energy transfer that takes place as curing occurs. We have studied three newly-poured bridges so far, the most recent, during June, 1998, on I-87 where it crosses the Kayaderosseras Creek.

• LBA

In the Large-Scale Bioshpere-Atmosphere Experiment in Amazonia, there are three sites (primary forest, logged forest, and pasture) to measure turbulent fluxes of heat, moisture, and CO₂ in the Santarem region.  A major focus will be to determine how carbon fluxes are influenced by natural and human-induced landscape inhomogeneities.  Scales of inhomogeneities addressed range from the river-land contrast, the pasture-forest contrast, and the gap-closed canopy contrast inside the forest.  Special attention will go to understanding how changes in agricultural practices in the Amazon alter carbon exchanges in cleared areas. 

• NIGEC/HF/DrainoHF

At Harvard Forest, we are conducting a program of careful analysis of existing data, continued operation of instruments now in the field, and measured deployment of new sensors.  We designed and deployed a unique subcanopy network of wind, temperature and CO₂ sensors.  Boundary layer observations are being used to estimate surface CO₂ and water vapor fluxes.  Historical climate and streamflow data are acquired and analyzed in concert with the direct flux measurements.

• DOT Project

Our plan was that when the data were available in real-time, SUNYA would begin research related to natural and artificial surface state prediction for the local area. SUNYA would have sought input from NWS staff in the development of the models which will be one-dimensional energy balance models that determine surface temperatures and state (i.e., wet, dry, icy, snowy) by determining the exchange of energy between the surface, the atmosphere above it, and the ground below it. The idea was to apply the models to both natural surfaces such as fields and to artificial surfaces such as roads gaining valuable insight into the differences between the energy balances of different surfaces. 

• Hydrology

In the extensive deciduous forests of the eastern U.S., the onset of evapotranspiration in spring represents a widespread land cover change. The abrupt change in evapotranspiration withdraws some of the groundwater that feeds the streams, leading to a widespread reduction in streamflow. We examine seasonal variations in streamflow recession (the decline in streamflow following rainfall) and the evapotranspiration-driven diurnal streamflow cycle observed in small watersheds.

• HVAMS

  This proposed investigation of the Hudson Valley, New York intends to examine how local topography and land use patterns affect boundary layer dynamics under predominantly fair-weather conditions.  To identify the physical processes responsible for the development of local winds, we propose to integrate separate information from existing surface and upper air weather observing stations into a single database, facilitating analysis of valley phenomena.