Filters: Tags: Paleoclimatology (X)8 results (6ms)
This data set collects, from peer-reviewed research, values of sea surface temperature (SST) that occurred at various sites across the Earth during a brief period of the mid-Piacenzian
A key feature of anticipated 21st century droughts in Southwest North America is the concurrence of elevated temperatures and increased aridity. Instrumental records and paleoclimatic evidence for past prolonged drought in the Southwest that coincide with elevated temperatures can be assessed to provide insights on temperature-drought relations and to develop worst-case scenarios for the future. In particular, during the medieval period, âˆ¼AD 900-1300, the Northern Hemisphere experienced temperatures warmer than all but the most recent decades. Paleoclimatic and model data indicate increased temperatures in western North America of approximately 1 Â°C over the long-term mean. This was a period of extensive...
The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. These data are provided as digital representations of mid Pliocene boundary conditions stored in NetCDF format for use with climate models.
Data release for Assessing the Uncertainties in Climatic Estimates Based on Vegetation Assemblages: Examples from Modern Vegetation Assemblages in the American Southwest
This data release includes climatic variables and associated descriptive material created for the purpose of assessing uncertainties associated with climatic estimates based on vegetation assemblages (Thompson and others, 2021). The data are from the interior of the western United States, including all of Arizona, and portions of California, Colorado, Nevada, New Mexico, Texas, and Utah. The data are observed, interpolated, and estimated values for the mean temperature of the coldest month (MTCO, degrees C), mean temperature of the warmest month (MTWA, degrees C), and mean annual total precipitation (MAP, mm).
Data Release for Holocene Paleohydrology from alpine lake sediment, Emerald Lake, Wasatch Plateau of central Utah, USA
Holocene sediments at Emerald Lake in central Utah (3090 m a.s.l), document the paleohydroclimatic history of the western Upper Colorado River headwater region. Multi-proxy analyses of sediment composition, mineralogy, and stable isotopes of carbonate (d18O and d13C) show changes in effective moisture for the past ca. 10,000 years at millennial to decadal timescales. Emerald Lake originated as a shallow closed-basin cirque pond during the early Holocene. By ca. 7000 cal yr BP, higher lake levels and carbonate d18O values indicate rising effective moisture and higher proportions of summer precipitation continued at least until ca. 5500 cal yr BP when a landslide entered the lake margin. Between ca. 4500 and 2400...
Tree-ring footprint of joint hydrologic drought in Sacramento and Upper Colorado river basins, western USA
Growing and changing demands on water supply, along with natural climate variability and possible anthropogenically induced climate change, make water resource management and planning increasingly challenging, particularly in arid regions. Instrumental climate and gaged streamflow records provide just a snapshop of recent natural hydrologic variability. In this paper, we use tree-ring-based annual streamflow reconstructions for the Sacramento River in California and the Blue River in western Colorado to analyze the temporal and spatial variability of widespread drought simultaneously affecting both basins over the past five centuries. Stability of joint-drought episodes and the covariation of reconstructed flows...
Projected future vegetation changes for the Northwest United States and Southwest Canada at a fine spatial resolution using a dynamic global vegetation model
Future climate change may significantly alter the distributions of many plant taxa. The effects of climate change may be particularly large in mountainous regions where climate can vary significantly with elevation. Understanding potential future vegetation changes in these regions requires methods that can resolve vegetation responses to climate change at fine spatial resolutions. This research was projected using three models: cgcm31, hadley, and current. We used LPJ, a dynamic global vegetation model, to assess potential future vegetation changes for a large topographically complex area of the northwest United States and southwest Canada (38.0–58.0°N latitude by 136.6–103.0°W longitude). LPJ is a process-based...
Integrated loessite-paleokarst depositional system, early Pennsylvanian Molas Formation, Paradox Basin, southwestern Colorado, U.S.A.
Mississippian paleokarst served as a dust trap for the oldest known Paleozoic loessite in North America. The early Pennsylvanian Molas Formation consists of loessite facies (sorted, angular, coarse-grained quartz siltstone), infiltration facies (loess redeposited as cave sediments within paleokarst features of the underlying Mississippian Leadville Limestone), colluvium facies (loess infiltrated into colluvium surrounding paleokarst towers) and fluvial facies (siltstone-rich, fluvial channel and floodplain deposits with paleosols). The depositional system evolved from an initial phase of infiltration and colluvium facies that were spatially and temporally related to the paleokarst surface, to loessite facies that...