An increase in anthropogenic activities since the industrial revolution, primarily due to burning of fossil fuels and changes in land cover, has resulted in a steady increase in the global mean atmospheric CO2 concentrations. While there is unequivocal scientific evidence on global warming and its multidimensional impacts on natural and...
With the recent advent of commercial laser absorption spectrometers, field studies measuring stable isotope ratios of hydrogen and oxygen in water vapor have proliferated. These pioneering analyses have provided invaluable feedback about best strategies for optimizing instrumental accuracy, yet questions still remain about instrument performance and calibration approaches for multi-year...
The isotopic composition of water vapour provides integrated perspectives on the hydrological histories of air masses and has been widely used for tracing physical processes in hydrological and climatic studies. Over the last two decades, the infrared laser spectroscopy technique has been used to measure the isotopic composition of water...
This report details ocean water salinity and stable isotope measurements (deuterium (D) and 18O) in water collected from April 17 2018 to April 21 2018 in the coastal waters of Oregon, USA. Measurements were made from surface, ship flow-through, and CTD rosette bottle samples collected as part of a student-led...
The topics in this dissertation are centered around the way that trees respond to environmental stress in the climates where they occur. Though forests across the planet are expected to experience change in local climate due to historic and ongoing anthropogenic greenhouse gas emissions, the effects of climate change will...
The diurnal variability and the environmental conditions that support the moisture resurgence of MJO events observed during the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY)/DYNAMO campaign in October–December 2011 are investigated using in situ observations and the cloud-resolving fully air–ocean–wave Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS). Spectral density and...
Spatial climate datasets of 1981–2010 long-term mean monthly average dew point and minimum and maximum vapor pressure deficit were developed for the conterminous United States at 30-arcsec (~800m) resolution. Interpolation of long-term averages (twelve monthly values per variable) was performed using PRISM (Parameter-elevation Relationships on Independent Slopes Model). Surface stations...
Severe droughts occurred in the western United States during recent decades, and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on...
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) max-
imum tree height, and (c) leaf: sapwood area ratio plotted against
the average growing-year
Uncertainties in general circulation model (GCM) representations of marine boundary layer (MBL) shallow cloud cover contribute substantially to the spread in model predictions of future climate. Further uncertainties in GCM output arise from an incomplete understanding of cloud-aerosol interactions. For example, the Fifth Assessment Report from the Intergovernmental Panel on...
Ice cores are considered the gold standard for recording past climate and biogeochemical changes. However, gas records derived from ice core analysis have until now been largely limited to centennial and longer timescales because sufficient temporal resolution and analytical precision have been lacking, except during rare times when atmospheric concentrations...