Open Access. Powered by Scholars. Published by Universities.®
Oceanography and Atmospheric Sciences and Meteorology Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Climate change (3)
- China (2)
- Climate change, future climate (2)
- Paleoclimate (2)
- Biomarker (1)
-
- Carbon dioxide (1)
- Caves and Karst (1)
- Central America (1)
- Dynamic land ecosystem model (DLEM) (1)
- Forest ecosystem (1)
- Future climate (1)
- Geochemistry and Climatology (1)
- Global warming (1)
- Global warming potential (1)
- Hydrogeology (1)
- Lake sediments (1)
- Lake sediments, biogeochemistry (1)
- Lofted (1)
- Methane (1)
- Mexico (1)
- Net carbon exchange (NCE) (1)
- Net primary production (NPP) (1)
- Nitrous oxide (1)
- Norway (1)
- Ozone (O3) (1)
- Paleoclimatology (1)
- Regional climate model (1)
Articles 1 - 9 of 9
Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology
The Effects Of Evapotranspiration Upon Recharge Using The Stable Isotopes Of Oxygen And Hydrogen In The Carbonate Aquifers Of The Cumberland Plateau In Southeast Kentucky, Lee J. Florea
Lee J Florea, PhD, P.G.
In this brief manuscript, we consider the variation of the stable isotopes of oxygen, δ18O, and hydrogen, δ2H, in samples collected during 2010 and 2011 from precipitation and shallow groundwater along the Cumberland Plateau of southeast Kentucky. These data from the 1,900-ha Redmond Creek karst aquifer lend insight into the source and timing of recharge to shallow groundwater in the epigenic karst of the U.S midcontinent. Specifically, we find that only 43% of precipitation remains as potential recharge after accounting for evapotranspiration, and 85% of this potential recharge occurs during only four two-week sampling periods. The isotopic composition of precipitation …
Net Exchanges Of Co2, Ch4, And N2o Between China's Terrestrial Ecosystems And The Atmosphere And Their Contributions To Global Climate Warming, Hanqin Tian, Xiaofeng Xu, Chaoqun (Crystal) Lu, Mingliang Liu, Wei Ren, Guangsheng Chen, Jerry Melillo, Jiyuan Liu
Net Exchanges Of Co2, Ch4, And N2o Between China's Terrestrial Ecosystems And The Atmosphere And Their Contributions To Global Climate Warming, Hanqin Tian, Xiaofeng Xu, Chaoqun (Crystal) Lu, Mingliang Liu, Wei Ren, Guangsheng Chen, Jerry Melillo, Jiyuan Liu
Chaoqun (Crystal) Lu
China's terrestrial ecosystems have been recognized as an atmospheric CO2 sink; however, it is uncertain whether this sink can alleviate global warming given the fluxes of CH4 and N2O. In this study, we used a process-based ecosystem model driven by multiple environmental factors to examine the net warming potential resulting from net exchanges of CO2, CH4, and N2O between China's terrestrial ecosystems and the atmosphere during 1961–2005. In the past 45 years, China's terrestrial ecosystems were found to sequestrate CO2 at a rate of 179.3 Tg C yr−1 with a 95% confidence range of (62.0 Tg C yr−1, 264.9 Tg …
Impacts Of Tropospheric Ozone And Climate Change On Net Primary Productivity And Net Carbon Exchange Of China's Forest Ecosystems, Wei Ren, Hanqin Tian, Bo Tao, Arthur Chappelka, Ge Sun, Chaoqun (Crystal) Lu, Mingliang Liu, Guangsheng Chen, Xiaofeng Xu
Impacts Of Tropospheric Ozone And Climate Change On Net Primary Productivity And Net Carbon Exchange Of China's Forest Ecosystems, Wei Ren, Hanqin Tian, Bo Tao, Arthur Chappelka, Ge Sun, Chaoqun (Crystal) Lu, Mingliang Liu, Guangsheng Chen, Xiaofeng Xu
Chaoqun (Crystal) Lu
We investigated how ozone pollution and climate change/variability have interactively affected net primary productivity (NPP) and net carbon exchange (NCE) across China's forest ecosystem in the past half century. Using the dynamic land ecosystem model (DLEM) in conjunction with 10-km-resolution gridded historical data sets (tropospheric O3 concentrations, climate variability/change, and other environmental factors such as land-cover/land-use change (LCLUC), increasing CO2 and nitrogen deposition), we conducted nine simulation experiments to: (1) investigate the temporo-spatial patterns of NPP and NCE in China's forest ecosystems from 1961–2005; and (2) quantify the effects of tropospheric O3 pollution alone or in combination with climate variability …
The Effect Of Zonally Asymmetric Ozone Heating On The Northern Hemisphere Winter Polar Stratosphere, J. P. Mccormack, T. R. Nathan, E. C. Cordero
The Effect Of Zonally Asymmetric Ozone Heating On The Northern Hemisphere Winter Polar Stratosphere, J. P. Mccormack, T. R. Nathan, E. C. Cordero
Eugene C. Cordero
[1] Previous modeling studies have found significant differences in winter extratropical stratospheric temperatures depending on the presence or absence of zonally asymmetric ozone heating (ZAOH), yet the physical mechanism causing these differences has not been fully explained. The present study describes the effect of ZAOH on the dynamics of the Northern Hemisphere extratropical stratosphere using an ensemble of free-running atmospheric general circulation model simulations over the 1 December - 31 March period. We find that the simulations including ZAOH produce a significantly warmer and weaker stratospheric polar vortex in mid-February due to more frequent major stratospheric sudden warmings compared to …
Climate Change In Central America And Mexico: Regional Climate Model Validation And Climate Change Projections, Ambarish V. Karmalkar, Raymond S. Bradley, Henry F. Diaz
Climate Change In Central America And Mexico: Regional Climate Model Validation And Climate Change Projections, Ambarish V. Karmalkar, Raymond S. Bradley, Henry F. Diaz
Raymond S Bradley
Central America has high biodiversity, it harbors high-value ecosystems and it’s important to provide regional climate change information to assist in adaptation and mitigation work in the region. Here we study climate change projections for Central America and Mexico using a regional climate model. The model evaluation shows its success in simulating spatial and temporal variability of temperature and precipitation and also in capturing regional climate features such as the bimodal annual cycle of precipitation and the Caribbean low-level jet. A variety of climate regimes within the model domain are also better identified in the regional model simulation due to …
Where Do We Stand On Global Warming?, Raymond S. Bradley
Where Do We Stand On Global Warming?, Raymond S. Bradley
Raymond S Bradley
Global temperatures have risen by ~0.8°C since the end of the 19th century. This increase has not been linear, as there have been periods when temperatures were stable for short periods before rising once again. The reasons for these changes in the rate of temperature rise are related to anthropogenic factors (sulphate aerosol pollution versus greenhouse gas inputs to the atmosphere) as well as to natural factors (volcanic eruptions, solar irradiance variations, El Ni.o/Southern Oscillation [ENSO] fluctuations, etc). Over the last decade or so, temperatures have not risen at the same rate as in previous decades, and this has led …
Natural Archives, Changing Climates, Raymond S. Bradley
Natural Archives, Changing Climates, Raymond S. Bradley
Raymond S Bradley
Climatic changes have occurred throughout human history, but instrumental measurements do not provide us with a very long perspective on climate variations. In many regions, instrumental records only extend back a century or two. To understand the longer-term variability of the climate system, we rely on natural archives— sediments, ice caps, peat bogs, cave deposits, banded corals and tree rings—in which a record of past changes in climate has been preserved. They are a treasure trove of the climatic and environmental history of the planet and provide information about factors that may have caused the climate to change, such as …
High-Resolution Paleoclimatology, Raymond S. Bradley
High-Resolution Paleoclimatology, Raymond S. Bradley
Raymond S Bradley
High resolution paleoclimatology involves studies of natural archives as proxies for past climate variations at a temporal scale that is comparable to that of instrumental data. In practice, this generally means annually resolved records, from tree rings, ice cores, banded corals, laminated speleothems and varved sediments. New analytical techniques offer many unexplored avenues of research in high resolution paleoclimatology. However, critical issues involving accuracy of the chronology, reproducibility of the record, frequency response to forcing and other factors, and calibration of the proxies remain. Studies of proxies at high resolution provide opportunities to examine the frequency and magnitude of extreme …
A Multi-Proxy Approach To Assessing Isolation Basin Stratigraphy From The Lofoten Islands, Norway, Nicholas L. Balascio, Zhaohui Zhang, Raymond S. Bradley, Bianca B. Perren, Svein-Olaf Dahl, Jostein Bakke
A Multi-Proxy Approach To Assessing Isolation Basin Stratigraphy From The Lofoten Islands, Norway, Nicholas L. Balascio, Zhaohui Zhang, Raymond S. Bradley, Bianca B. Perren, Svein-Olaf Dahl, Jostein Bakke
Raymond S Bradley
This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, bulk organic matter properties, molecular biomarkers, diatom assemblages, and elemental profiles acquired by scanning X-ray fluorescence. These characteristics of the sediment reflect detailed changes in salinity and water column conditions as the lake was progressively …