Steven Hostetler, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 82
Atmospheric transmission of North Atlantic Heinrich events
We model the response of the climate system during Heinrich event 2 (H2) by employing an atmospheric general circulation model, using boundary conditions based on the concept of a “canonical” Heinrich event. The canonical event is initialized with a full-height Laurentide ice sheet (LIS) and CLIMAP sea surface temperatures (SSTs), followed by lowering of the LIS, then warming of North Atlantic SST
Authors
S. W. Hostetler, P.U. Clark, P. J. Bartlein, A.C. Mix, N.J. Pisias
Simulating the water balance of the Aral Sea with a coupled regional climate-lake model
Before coupled atmosphere-lake models can be used to study the response of large lake systems to climatic forcings, we must first evaluate how well they simulate the water balance and associated lake atmosphere interactions under present-day conditions. We evaluate the hydrology simulated by a lake model coupled to NCAR's regional climate model (RegCM2) in a study of the Aral Sea. The meteorologic
Authors
E.E. Small, L.C. Sloan, S. Hostetler, F. Giorgi
Foraminiferal faunal estimates of paleotemperature: Circumventing the no-analog problem yields cool ice age tropics
The sensitivity of the tropics to climate change, particularly the amplitude of glacial-to-interglacial changes in sea surface temperature (SST), is one of the great controversies in paleoclimatology. Here we reassess faunal estimates of ice age SSTs, focusing on the problem of no-analog planktonic foraminiferal assemblages in the equatorial oceans that confounds both classical transfer function a
Authors
A.C. Mix, A.E. Morey, N. G. Pisias, S. W. Hostetler
Response of North American freshwater lakes to simulated future climates
We apply a physically based lake model to assess the response of North American lakes to future climate conditions as portrayed by the transient trace-gas simulations conducted with the Max Planck Institute (ECHAM4) and the Canadian Climate Center (CGCM1) atmosphere-ocean general circulation models (A/OGCMs). To quantify spatial patterns of lake responses (temperature, mixing, ice cover, evaporati
Authors
S. W. Hostetler, E.E. Small
Reassessment of ice-age cooling of the tropical ocean and atmosphere
The CLIMAP project's reconstruction of past sea surface temperature inferred limited ice-age cooling in the tropical oceans. This conclusion has been controversial, however, because of the greater cooling indicated by other terrestrial and ocean proxy data. A new faunal sea surface temperature reconstruction, calibrated using the variation of foraminiferal species through time, better represents i
Authors
S. W. Hostetler, A.C. Mix
A strategy for assessing potential future changes in climate, hydrology, and vegetation in the Western United States
Historical and geological data indicate that significant changes can occur in the Earth's climate on time scales ranging from years to millennia. In addition to natural climatic change, climatic changes may occur in the near future due to increased concentrations of carbon dioxide and other trace gases in the atmosphere that are the result of human activities. International research efforts using
Authors
Robert Stephen Thompson, Steven W. Hostetler, Patrick J. Bartlein, Katherine H. Anderson
Modelling lake behaviour: how can we use mechanistic models to further our understanding of the response of lakes to climate change?
No abstract available.
Authors
P. J. Bartlein, L. Bengtsson, S. P. Harrison, S. Hostetler, K. Hsü, B. Qin, J. Vassiljev
Sensitivity of aquatic ecosystems to climatic and anthropogenic changes: The basin and range, American Southwest and Mexico
Variability and unpredictability are characteristics of the aquatic ecosystems, hydrological patterns and climate of the largely dryland region that encompasses the Basin and Range, American Southwest and western Mexico. Neither hydrological nor climatological models for the region are sufficiently developed to describe the magnitude or direction of change in response to increased carbon dioxide;
Authors
N. B. Grimm, A. Chacon, Clifford N. Dahm, S. W. Hostetler, O.T. Lind, P.L. Starkweather, W.W. Wurtsbaugh
Assessment of climate change and freshwater ecosystems of the Rocky Mountains, USA and Canada
The Rocky Mountains in the USA and Canada encompass the interior cordillera of western North America, from the southern Yukon to northern New Mexico. Annual weather patterns are cold in winter and mild in summer. Precipitation has high seasonal and interannual variation and may differ by an order of magnitude between geographically close locales, depending on slope, aspect and local climatic and o
Authors
F. Richard Hauer, Jill Baron, K. Campbell, K.D. Fausch, S. W. Hostetler, G.H. Leavesley, P.R. Leavitt, Diane M. McKnight, J. A. Stanford
Climatic controls of western U.S. glaciers at the last glacial maximum
We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net mass balance of late-Pleistocene mountain glaciers in this region of diverse topog
Authors
S. W. Hostetler, P.U. Clark
The California current of the last glacial maximum: reconstruction at 42°N based on multiple proxies
Multiple paleoceanographic proxies in a zonal transect across the California Current near 42°N record modern and last glacial maximum (LGM) thermal and nutrient gradients. The offshore thermal gradient, derived from foraminiferal species assemblages and oxygen isotope data, was similar at the LGM to that at present (warmer offshore), but average temperatures were 3.3° ±1.5°C colder. Observed gradi
Authors
Joseph D. Ortiz, Alan C. Mix, Steven W. Hostetler, Michaele Kashgarian
Science and Products
Filter Total Items: 82
Atmospheric transmission of North Atlantic Heinrich events
We model the response of the climate system during Heinrich event 2 (H2) by employing an atmospheric general circulation model, using boundary conditions based on the concept of a “canonical” Heinrich event. The canonical event is initialized with a full-height Laurentide ice sheet (LIS) and CLIMAP sea surface temperatures (SSTs), followed by lowering of the LIS, then warming of North Atlantic SST
Authors
S. W. Hostetler, P.U. Clark, P. J. Bartlein, A.C. Mix, N.J. Pisias
Simulating the water balance of the Aral Sea with a coupled regional climate-lake model
Before coupled atmosphere-lake models can be used to study the response of large lake systems to climatic forcings, we must first evaluate how well they simulate the water balance and associated lake atmosphere interactions under present-day conditions. We evaluate the hydrology simulated by a lake model coupled to NCAR's regional climate model (RegCM2) in a study of the Aral Sea. The meteorologic
Authors
E.E. Small, L.C. Sloan, S. Hostetler, F. Giorgi
Foraminiferal faunal estimates of paleotemperature: Circumventing the no-analog problem yields cool ice age tropics
The sensitivity of the tropics to climate change, particularly the amplitude of glacial-to-interglacial changes in sea surface temperature (SST), is one of the great controversies in paleoclimatology. Here we reassess faunal estimates of ice age SSTs, focusing on the problem of no-analog planktonic foraminiferal assemblages in the equatorial oceans that confounds both classical transfer function a
Authors
A.C. Mix, A.E. Morey, N. G. Pisias, S. W. Hostetler
Response of North American freshwater lakes to simulated future climates
We apply a physically based lake model to assess the response of North American lakes to future climate conditions as portrayed by the transient trace-gas simulations conducted with the Max Planck Institute (ECHAM4) and the Canadian Climate Center (CGCM1) atmosphere-ocean general circulation models (A/OGCMs). To quantify spatial patterns of lake responses (temperature, mixing, ice cover, evaporati
Authors
S. W. Hostetler, E.E. Small
Reassessment of ice-age cooling of the tropical ocean and atmosphere
The CLIMAP project's reconstruction of past sea surface temperature inferred limited ice-age cooling in the tropical oceans. This conclusion has been controversial, however, because of the greater cooling indicated by other terrestrial and ocean proxy data. A new faunal sea surface temperature reconstruction, calibrated using the variation of foraminiferal species through time, better represents i
Authors
S. W. Hostetler, A.C. Mix
A strategy for assessing potential future changes in climate, hydrology, and vegetation in the Western United States
Historical and geological data indicate that significant changes can occur in the Earth's climate on time scales ranging from years to millennia. In addition to natural climatic change, climatic changes may occur in the near future due to increased concentrations of carbon dioxide and other trace gases in the atmosphere that are the result of human activities. International research efforts using
Authors
Robert Stephen Thompson, Steven W. Hostetler, Patrick J. Bartlein, Katherine H. Anderson
Modelling lake behaviour: how can we use mechanistic models to further our understanding of the response of lakes to climate change?
No abstract available.
Authors
P. J. Bartlein, L. Bengtsson, S. P. Harrison, S. Hostetler, K. Hsü, B. Qin, J. Vassiljev
Sensitivity of aquatic ecosystems to climatic and anthropogenic changes: The basin and range, American Southwest and Mexico
Variability and unpredictability are characteristics of the aquatic ecosystems, hydrological patterns and climate of the largely dryland region that encompasses the Basin and Range, American Southwest and western Mexico. Neither hydrological nor climatological models for the region are sufficiently developed to describe the magnitude or direction of change in response to increased carbon dioxide;
Authors
N. B. Grimm, A. Chacon, Clifford N. Dahm, S. W. Hostetler, O.T. Lind, P.L. Starkweather, W.W. Wurtsbaugh
Assessment of climate change and freshwater ecosystems of the Rocky Mountains, USA and Canada
The Rocky Mountains in the USA and Canada encompass the interior cordillera of western North America, from the southern Yukon to northern New Mexico. Annual weather patterns are cold in winter and mild in summer. Precipitation has high seasonal and interannual variation and may differ by an order of magnitude between geographically close locales, depending on slope, aspect and local climatic and o
Authors
F. Richard Hauer, Jill Baron, K. Campbell, K.D. Fausch, S. W. Hostetler, G.H. Leavesley, P.R. Leavitt, Diane M. McKnight, J. A. Stanford
Climatic controls of western U.S. glaciers at the last glacial maximum
We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net mass balance of late-Pleistocene mountain glaciers in this region of diverse topog
Authors
S. W. Hostetler, P.U. Clark
The California current of the last glacial maximum: reconstruction at 42°N based on multiple proxies
Multiple paleoceanographic proxies in a zonal transect across the California Current near 42°N record modern and last glacial maximum (LGM) thermal and nutrient gradients. The offshore thermal gradient, derived from foraminiferal species assemblages and oxygen isotope data, was similar at the LGM to that at present (warmer offshore), but average temperatures were 3.3° ±1.5°C colder. Observed gradi
Authors
Joseph D. Ortiz, Alan C. Mix, Steven W. Hostetler, Michaele Kashgarian