A5087392163- Plant Water Relations and Carbon Dynamics
- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Atmospheric aerosols and clouds
- Remote Sensing in Agriculture
- Wind and Air Flow Studies
- Geography and Environmental Studies
- Plant responses to elevated CO2
- Environmental and biological studies
- Atmospheric chemistry and aerosols
- Forest ecology and management
- Fire effects on ecosystems
- Tree-ring climate responses
- Fluid Dynamics and Turbulent Flows
- Precipitation Measurement and Analysis
- Aeolian processes and effects
- Cryospheric studies and observations
- Tropical and Extratropical Cyclones Research
- Atmospheric Ozone and Climate
- Forest Management and Policy
- Remote Sensing and LiDAR Applications
- Climate change and permafrost
- Concrete and Cement Materials Research
- Concrete Properties and Behavior
Albany State University
2008-2024
University at Albany, State University of New York
2014-2024
State University of New York
1993-2024
The Graduate Center, CUNY
2023
CUNY Advanced Science Research Center
2023
NSF National Center for Atmospheric Research
1983-2020
New York State Department of Environmental Conservation
2020
San Jose State University
2020
University of California, Irvine
2020
Simpson Weather Associates (United States)
2019
Net uptake of carbon dioxide (CO 2 ) measured by eddy covariance in a 60- to 80-year-old forest averaged 2.0 ± 0.4 megagrams per hectare year during 1993 2000, with interannual variations exceeding 50%. Biometry indicated storage 1.6 over 8 years, 60% live biomass and the balance coarse woody debris soils, confirming eddy-covariance results. Weather seasonal climate (e.g., growing-season length or cloudiness) regulated fluctuations uptake. Legacies prior disturbance management, especially...
We analyzed 13 years (1992−2004) of CO 2 flux data, biometry, and meteorology from a mixed deciduous forest in central Massachusetts. Annual net uptake ranged 1.0 to 4.7 Mg‐C ha −1 yr , with an average 2.5 . Uptake rates increased systematically, nearly doubling over the period despite age 75–110 years; there were parallel increases midsummer photosynthetic capacity at high light level (21.5−31.5 μ mole m −2 s ), woody biomass (101−115 1993−2005, mostly due growth one species, red oak), peak...
The goal of the Boreal Ecosystem‐Atmosphere Study (BOREAS) is to improve our understanding interactions between boreal forest biome and atmosphere in order clarify their roles global change. This overview paper describes science background motivations for BOREAS experimental design operations 1994 1996 field years. findings 83 papers this journal special issue are reviewed. In section 7, important scientific results project date summarized future research directions identified.
Measurements of vertical fluxes for CO 2 and O 3 were made at a level 10 m above the canopy Amazon forest during wet season, using eddy correlation techniques. Vertical profiles recorded continuously from to soil surface, floor respiration was measured enclosures. Nocturnal by ecosystem averaged 2.57 kgC/ha/h, with about 85% floor. During daytime, taken up mean rate 4.4 kgC/ha/h. Net uptake carbon dioxide increased solar flux 0.015 (kgC/ha/h)/(W −2 ), corresponding fixation 0.0076 moles per...
During the growing season, nighttime ecosystem respiration emits 30–100% of daytime net photosynthetic uptake carbon, and therefore measurements rates understanding its control by environment are important for exchange. Ecosystem can be measured at night eddy covariance methods, but data may not reliable because low turbulence or other methodological problems. We used relationships between woody tissue, foliage, soil temperature, with temperature records collected on site to estimate six...
Abstract Eddy covariance flux observations at a deciduous temperate forest site (83 days) and boreal (21 are analyzed for midday periods (1100–1400 LT). Approximate stationarity of the time series is demonstrated, ensemble-averaged roughness sublayer cospectra presented. Spectral cospectral forms in more peaked than those found an inertial sublayer. They exhibit similar dependent on (z − d)/(h d), where d displacement height h canopy height. The inertial-layer spectral recovered when made...
CHUVA, meaning “rain” in Portuguese, is the acronym for Cloud Processes of Main Precipitation Systems Brazil: A Contribution to Cloud-Resolving Modeling and Global Measurement (GPM). The CHUVA project has conducted five field campaigns; sixth last campaign will be held Manaus 2014. primary scientific objective contribute understanding cloud processes, which represent one least understood components weather climate system. campaigns were designed investigate specific tropical regimes. first...
Summary The impact of increases in drought frequency on the Amazon forest's composition, structure and functioning remain uncertain. We used a process‐ individual‐based ecosystem model ( ED 2) to quantify vulnerability increased recurrence. generated meteorologically realistic, drier‐than‐observed rainfall scenarios for two forest sites, Paracou (wetter) Tapajós (drier), evaluate impacts more frequent droughts biomass, composition. wet site was insensitive tested scenarios, whereas at dry...
We present 5 years of NO y and O 3 eddy flux concentration measurements x at Harvard Forest (1990–1994), a mixed deciduous forest in central Massachusetts, 2 months data for spruce woodland near Schefferville, Quebec, during the NASA ABLE3B/Northern Wetlands Study (1990). Mean midday values net dry from atmosphere to canopy were 3.4 3.2 μmole m −2 hr −1 summer winter, respectively, 0.5 Schefferville summer. Nighttime 1.3, 2.0, 0.15 , respectively. For 1990–1994, annual deposition nitrogen...
Temperate deciduous forests exhibit dramatic seasonal changes in surface exchange properties following on the leaf area index. Nearly continuous measurements of turbulent and radiative fluxes above below canopy a red oak forest central Massachusetts have been ongoing since summer 1991. Several trends are obvious. Global solar albedo photosynthetically active radiation (PAR) both good indicators spring emergence autumnal defoliation canopy. The decreases throughout summer, change attributed...
At the time of leaf emergence in deciduous forests, markedly enhanced evapotranspiration leads to a rapid drop Bowen ratio. A small fraction this surface flux alteration converges into boundary layer, and can be detected mean temperature humidity daily increments at surface. simple technique is presented for identifying response climate data extracting series date spring onset “spring intensity,” measure energy budget partition change spring. tendency ratio B′ found from changes increment...
An analysis of boundary layer cumulus clouds and their impact on land surface–atmosphere exchange is presented. Seasonal trends indicate that in response to increasing insolation sensible heat flux, both the mixed-layer height (zi) lifting condensation level (LCL) peak (∼1250 1700 m) just before growing season commences. With commencement transpiration, Bowen ratio falls abruptly infusion additional moisture into layer, zi LCL decrease. By late spring, cloud frequency increases sharply, as...
On clear nights with appreciable radiative cooling, rates of change mean quantities observed in the first 1 or 2 h after sunset are many times larger than they subsequently until sunrise. These variations include large temperature drops, specific humidity increases, and abrupt wind speed decay. The early evening transition (EET) is dominated by vertical surface flux convergence as turbulent mixing layer becomes confined to a shallow stable near surface. Effects heterogeneities enhanced...
Exchanges of methane and carbon dioxide between the atmosphere Arctic tundra were measured continuously near Bethel, Alaska (61°05.41'N 162°00.92'W), for 5 weeks during July August 1988. Fluxes obtained directly using eddy correlation at 12‐m altitude, concentrations sequentially eight altitudes 0 12 m. A prototype differential infrared absorption instrument based on a Zeeman‐split HeNe laser was used determination flame ionization detector total hydrocarbons (THC). Methane found to account...
The budgets of O 3 , NO x (NO+NO 2 ), reactive nitrogen (NO y and acetic acid in the 0–6 km column over western Alaska summer are examined by photochemical modeling aircraft ground‐based measurements from Arctic Boundary Layer Expedition (ABLE 3A). It is found that concentrations region regulated mainly input stratosphere, losses comparable magnitude photochemistry deposition. (10–50 ppt) sufficiently high to slow down loss appreciably relative a ‐free atmosphere; if no were present,...
Abstract We describe the salient features of a field study whose goals are to quantify vertical distribution plant-emitted hydrocarbons and their contribution aerosol cloud condensation nuclei production above central Amazonian rain forest. Using observing systems deployed on 50-m meteorological tower, complemented with tethered balloon deployments, aerosols was determined under different boundary layer thermodynamic states. The forest emits sufficient reactive hydrocarbons, such as isoprene...
Fluxes of carbon dioxide, water vapor, sensible heat, and momentum obtained over the boreal forest from Twin Otter aircraft six tower‐based systems are compared. These measurements were collected as part Boreal Ecosystem‐Atmosphere Study (BOREAS) during three intensive field campaigns between May 25 September 17, 1994. The representativeness BOREAS is discussed. Even though net radiation aircraft‐ agreed well, in general, tended to observe larger latent heat smaller fluxes than towers. CO 2...
We have observed a number of events that lead to nocturnal turbulent mixing between the Amazon rain forest and atmosphere. Two mechanisms weaken stable thermal inversion at canopy top are identified with release carbon dioxide concurrent heat flux into moisture out canopy. In first mechanism, abrupt onset cloudiness interrupts radiative cooling, leading period lowered Richardson enhanced heat, moisture, fluxes. Significant exchange atmosphere can also occur even on totally clear nights. On...
Measurements carried out over the rain forest of central Amazonia during NASA Amazon Boundary Layer Experiment (ABLE 2A) are used to examine structure and growth atmospheric mixed layer. Fluxes sensible latent heat were measured at top canopy, measurements temperature, moisture, horizontal wind made in above layer by means a tethered balloon, rawinsonde, aircraft. The mixing grows rapidly 5–8 cm s −1 soon after sunrise mean maximum height 1200 m 1300 local standard time (LST). Mixed heights...