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Temporal Changes In The Observed Relationship Between Cloud Cover And Surface Air Temperature, Bomin Sun, Pavel Ya. Groisman, Raymond S. Bradley, Frank T. Keimig
Temporal Changes In The Observed Relationship Between Cloud Cover And Surface Air Temperature, Bomin Sun, Pavel Ya. Groisman, Raymond S. Bradley, Frank T. Keimig
Raymond S Bradley
The relationship between cloud cover and near-surface air temperature and its decadal changes are examined using the hourly synoptic data for the past four to six decades from five regions of the Northern Hemisphere: Canada, the United States, the former Soviet Union, China, and tropical islands of the western Pacific. The authors define the normalized cloud cover–surface air temperature relationship, NOCET or dT/dCL, as a temperature anomaly with a unit (one-tenth) deviation of total cloud cover from its average value. Then mean monthly NOCET time series (night- and daytime, separately) are area-averaged and parameterized as functions of surface air humidity …
Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, Mathias Yuille, Raymond S. Bradley
Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, Mathias Yuille, Raymond S. Bradley
Raymond S Bradley
Mean annual temperature trends in the tropical Andes were determined over the last six decades ( 1939-1998), to investigate the apparent inconsistency between the observed glacier retreat and the reported slight cooling trend in the lower tropical troposphere after 1979. Our results indicate that temperature in the tropical Andes has increased by 0. 10° - 0. I l °C/decade since 1939. The rate of warming has more than tripled over the last 25 years (0.32° - 0.34 °C/decade) and the last two years of the series, associated with the 1997/98 El Nino, were the warmest of the last six decades. …
Global Temperature Patterns In Past Centuries: An Interactive Presentation, Michael E. Mann, Ed Gille, Raymond S. Bradley, Malcolm K. Hughes, Jonathan Overpeck, Frank T. Keimig, Wendy Gross
Global Temperature Patterns In Past Centuries: An Interactive Presentation, Michael E. Mann, Ed Gille, Raymond S. Bradley, Malcolm K. Hughes, Jonathan Overpeck, Frank T. Keimig, Wendy Gross
Raymond S Bradley
The recent availability of global networks of annual or seasonal resolution proxy data, combined with the few long instrumental and historical climate records available during the past few centuries, make it possible now to reconstruct annual and seasonal spatial patterns of temperature variation, as well as hemispheric, global-mean, and regional temperature trends, several centuries back in time. Reconstructions of large-scale global or hemispheric trends during centuries past can place the instrumental assessments of climate during the twentieth century in a longer-term perspective and provide more robust evidence regarding the roles of potential climate forcings over time. The reconstructed spatial patterns …
Interannual Climate Variability In The Central Andes And Its Relation To Tropical Pacific And Atlantic Forcing, M. Vuille, Raymond S. Bradley, F. T. Keimig
Interannual Climate Variability In The Central Andes And Its Relation To Tropical Pacific And Atlantic Forcing, M. Vuille, Raymond S. Bradley, F. T. Keimig
Raymond S Bradley
The main spatiotemporal modes of interannual temperature and austral summer (DJF) precipitation variability in the Central Andes are identified based on a two-way principal component analysis (PCA) of 30-year (1961–1990) monthly station data and related to contemporaneous tropical Pacific and Atlantic sea surface temperature anomalies (SSTAs). In addition, various meteorological fields, based on National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP/NCAR) reanalysis, NOAA-Outgoing Longwave Radiation (OLR) and station data, are analyzed during periods of strong positive and negative SSTA and the respective composites tested for local significance using a Student's t-test approach. Temperature variability in the …
Detection And Attribution Oj Recent Climate Change: A Status Report, Raymond S. Bradley, Malcolm K. Hughes, Michael E. Mann
Detection And Attribution Oj Recent Climate Change: A Status Report, Raymond S. Bradley, Malcolm K. Hughes, Michael E. Mann
Raymond S Bradley
Barnett et al. (1999) provide an excellent review of progress in model-based detection and attribution during the past few years. Unfortunately, the section on "Paleoclimate proxies" is flawed. We cannot agree that "OUl' best estimates of natural variability will come from CGCMs" or that "paleoproxy data have serious shortcomings that preclude their use for this purpose." On the contrary. we believe that paleoclimate data provide the on(y prospect for realistically estimating the envelope of natural climate variability and validating model simulations. Here we point out several issues that lead to erroneous conclusions in their paper.
Streamflow And Suspended Sediment Transfer To Lake Sophia, Cornwallis Island, Nunavut, Canada, Carsten Braun, Douglas R. Hardy, Raymond S. Bradley, Michael J. Retelle
Streamflow And Suspended Sediment Transfer To Lake Sophia, Cornwallis Island, Nunavut, Canada, Carsten Braun, Douglas R. Hardy, Raymond S. Bradley, Michael J. Retelle
Raymond S Bradley
To ascertain the climatic controls on sediment transport to Lake Sophia, Comwallis Island, Nunavut, Canada, we made detailed hydrological and meteorological measurements in the Sophia River watershed through the 1994 melt season. Streamflow and suspended sediment transport are limited, on an annual time scale, by the supply of snow and sediment in the watershed. Suspended sediment yield from the watershed was only 0.46 t k:m-2, which is lower than any previously published yield for a stream in the High Arctic. Snowmelt rgnoff accounted for 88% of the annual suspended sediment load, whereas 6 and 9% were transported in response to …
Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, M. Vuille, Raymond S. Bradley
Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, M. Vuille, Raymond S. Bradley
Raymond S Bradley
Mean annual temperature trends in the tropical Andes were determined over the last six decades (1939–1998), to investigate the apparent inconsistency between the observed glacier retreat and the reported slight cooling trend in the lower tropical troposphere after 1979. Our results indicate that temperature in the tropical Andes has increased by 0.10°–0.11°C/decade since 1939. The rate of warming has more than tripled over the last 25 years (0.32°–0.34°C/decade) and the last two years of the series, associated with the 1997/98 El Niño, were the warmest of the last six decades. Temperature trends vary with altitude and show a generally reduced …