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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Climate Change In The Northeastern Us: Regional Climate Model Validation And Climate Change Projections, Fangxing Fan, Raymond S. Bradley, Michael A. Rawlins
Climate Change In The Northeastern Us: Regional Climate Model Validation And Climate Change Projections, Fangxing Fan, Raymond S. Bradley, Michael A. Rawlins
Raymond S Bradley
A high resolution regional climate model (RCM) is used to simulate climate of the recent past and to project future climate change across the northeastern US. Different types of uncertainties in climate simulations are examined by driving the RCM with different boundary data, applying different emissions scenarios, and running an ensemble of simulations with different initial conditions. Empirical orthogonal functions analysis and K-means clustering analysis are applied to divide the northeastern US region into four climatologically different zones based on the surface air temperature (SAT) and precipitation variability. The RCM simulations tend to overestimate SAT, especially over the northern part …
Climatic Changes In Mountain Regions Of The American Cordillera And The Tropics: Historical Changes And Future Outlook, Henry F. Diaz, Raymond S. Bradley, Liang Ning
Climatic Changes In Mountain Regions Of The American Cordillera And The Tropics: Historical Changes And Future Outlook, Henry F. Diaz, Raymond S. Bradley, Liang Ning
Raymond S Bradley
We review some recent work regarding climatic changes in selected mountain regions, with particular attention to the tropics and the American Cordillera. Key aspects of climatic variability and trends in these regions are the amplification of surface warming trends with height, and the strong modulation of tempera¬ture trends by tropical sea surface temperature, largely controlled by changes in El Niño–Southern Oscillation on multiple time scales. Corollary aspects of these climate trends include the increase in a critical plant growth temperature threshold, a rise in the freezing level surface, and the possibility of enhanced subtropical drying. Anthropogenic global warming projections indicate …
What Can We Learn From Past Warm Climates?, Raymond S. Bradley
What Can We Learn From Past Warm Climates?, Raymond S. Bradley
Raymond S Bradley
With limited political action to control fossil fuel use and associated greenhouse gas emissions, there is increasing emphasis on preparing for inevitable climate changes. But what changes should the world plan for? Model simulations provide some guidance about expected future climate scenarios, but we can also learn from past experience. Although there are no episodes in the past that are strictly comparable to the future, which is a world in which climate is modulated by human activities, there were warm periods in the past which resulted from other forcing factors. There are some lessons we can learn from paleoclimate records …
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 …
Threats To Water Supplies In The Tropical Andes, Raymond S. Bradley, Mathias Vuille, Henry F. Diaz, Walter Vergara
Threats To Water Supplies In The Tropical Andes, Raymond S. Bradley, Mathias Vuille, Henry F. Diaz, Walter Vergara
Raymond S Bradley
Climate models predict that greenhouse warming will cause temperatures to rise faster at higher than at lower altitudes. In the tropical Andes, glaciers may soon disappear, with potentially grave consequences for water supplies.
The Recent Climate Record: What It Can And Cannot Tell Us, Thomas R. Karl, J. Dan Tarpley, Robert G. Quayle, Henry F. Diaz, David A. Robinson, Raymond S. Bradley
The Recent Climate Record: What It Can And Cannot Tell Us, Thomas R. Karl, J. Dan Tarpley, Robert G. Quayle, Henry F. Diaz, David A. Robinson, Raymond S. Bradley
Raymond S Bradley
While a great deal of climate data have been gathered over the past hundred years, there remains a number of problems limiting our ability to fully utilize these data in reconstructing the climate of the past century. This is particularly true for research demanding high precision and/or detailed local or regional-scale climate analyses. In this review we consider our ability to quantify climate change with respect to near-surface air temperature (measured 1.25-2 m above ground), sea surface temperature, .precipitation, snow cover, sea ice, and vegetation measured from space and the Earth's surface. Among the data issues we discuss are calibration, …